The Largest Independent Automotive Information Resourse
Monday, August 10, 2009
Valve Mechanism
A valve mechanism is a group of components that
opens and closes the intake and exhaust valves in
the cylinder head at the appropriate timing.
Crankshaft
Timing sprocket
Timing chain
Intake camshaft
Intake valve
Exhaust camshaft
Exhaust valve
* The diagram shows a VVT-i system valve
mechanism.
Intake stroke
Exhaust stroke
Compression stroke
Combustion stroke
Hybrid vehicle
This type of vehicle is equipped with different types
of motive power, such as a gasoline engine and an
electric motor. Because the gasoline engine
generates electricity, this type of vehicle does not
require an external source for recharging the
battery. System of wheel driver uses 270V, on the
other hand, other electric 12V.
For example, during start- off, it uses an electric
motor that produces high power despite a low
speed. When the vehicle picks up speed, it
operates the gasoline engine that is more efficient
at higher speeds. By making the best use of both
types of motive force in this manner, it is effective
in reducing exhaust emission and improving fuel
economy.
Fuel cell hybrid vehicle (FCHV)
This electric vehicle uses the electric energy that is
created when the hydrogen fuel reacts with the
oxygen in the air to form water. Because it emits
only water, this is considered to be the ultimate
form of low- pollution vehicle, and is anticipated to
become the motive power for the next generation.
• The diagram indicates Toyota fuel cell hybrid
system.
Power control unit
Electric motor
Fuel cell stack
Hydrogen storage system
Secondary battery
Electric vehicle (EV)
This vehicle uses the power of the batteries to
operate the electric motor. Instead of using fuel, the
batteries require recharging. It offers many
advantages, including zero emissions and low
noise during operation. System of wheel drive uses
290V, on the other hand, other electric 12V.
• The diagram indicates Toyota EV system.
Power control unit
Electric motor
Battery
Diesel engine vehicle
Classification by Drive Method
Vehicles can be classified by the position of the
engine and drive wheels, and the number of drive
wheels.
FF (Front-engine, Front-drive)
Because a FF vehicle does not have a propeller
shaft, a spacious interior can be realized, thus
achieving excellent comfort.
FR (Front-engine, Rear-drive)
Because a FR vehicle has a good weight
balance, it excels in controllability and stability.
MR (Midship-engine, Rear-drive)
Because a MR vehicle has a good weight
balance on the front and rear axles, it excels in
controllability.
4WD (4-Wheels Drive)
Because a 4WD vehicle drives with four
wheels, it can operate under poor conditions in
a stable manner. Its weight is greater than that
of other types of vehicles.
Gasoline engine vehicle
This type of vehicle runs on an engine that uses
gasoline fuel. Because gasoline engines produce
high power yet come in a compact package, they
are widely used in passenger vehicles.
Similar engines are also used on the CNG engine,
the LPG engine and alcohol engine, which use
different types of fuel.
CNG: Compressed Natural Gas
LPG: Liquefied Petroleum Gas
Engine
Fuel tank (gasoline)
Tuesday, August 4, 2009
Master Cylinder
The master cylinder displaces hydraulic brake fluid under pressure to the rest of the brake system. When the brake pedal is depressed, the push rod moves the primary piston forward in the cylinder. The hydraulic pressure created and the force of the primary piston spring moves the secondary piston forward. When the forward movement of the pistons causes their primary cups to cover the bypass holes, hydraulic pressure builds up and is transmitted to the wheel cylinders. When the pedal retracts, the pistons allow fluid from the reservoir to fill the chamber if needed. Special sensors within the master cylinder are used to monitor the level of the fluid in the reservoir, and to alert the driver if a pressure imbalance develops. The standard dual master cylinder gives the front and rear brakes separate hydraulic systems. If a brake fluid leak occurs in one system, the other system will still operate, making it possible to stop the car.
FUEL SUPPLY
The internal-combustion engine is powered by the burning of a precise mixture of liquefied fuel and air in the cylinders’ combustion chambers. Fuel is stored in a tank until it is needed, then pumped to a carburetor or, in newer cars, to a fuel-injection system.
The carburetor controls the mixture of gas and air that travels to the engine. It mixes fuel with air at the head of a pipe, called the intake manifold, leading to the cylinders. A vacuum created by the downward strokes of pistons draws air through the carburetor and intake manifold. Inside the carburetor, the airflow transforms drops of fuel into a fine mist, or vapor. The intake manifold delivers the fuel vapor to the cylinders, where it is ignited.
All new cars produced today are equipped with fuel injection systems instead of carburetors. Fuel injectors spray carefully calibrated bursts of fuel mist into cylinders either at or near openings to the combustion chambers. Since the exact quantity of gas needed is injected into the cylinders, fuel injection is more precise, easier to adjust, and more consistent than a carburetor, delivering better efficiency, gas mileage, engine responsiveness, and pollution control. Fuel-injection systems vary widely, but most are operated or managed electronically.
High-performance automobiles are often fitted with air-compressing equipment that increases an engine’s output. By increasing the air and fuel flow to the engine, these features produce greater horsepower. Superchargers are compressors powered by the crankshaft. Turbochargers are turbine-powered compressors run by pressurized exhaust gas.
Fuel-Injection System: The fuel-injection system replaces the carburetor in most new vehicles to provide a more efficient fuel delivery system. Electronic sensors respond to varying engine speeds and driving conditions by changing the ratio of fuel to air. The sensors send a fine mist of fuel from the fuel supply through a fuel-injection nozzle into a combustion chamber, where it is mixed with air. The mixture of fuel and air triggers ignition.© Microsoft Corporation. All
ENGINE.
The basic components of an internal-combustion engine are the engine block, cylinder head, cylinders, pistons, valves, crankshaft, and camshaft. The lower part of the engine, called the engine block, houses the cylinders, pistons, and crankshaft. The components of other engine systems bolt or attach to the engine block. The block is manufactured with internal passageways for lubricants and coolant. Engine blocks are made of cast iron or aluminum alloy and formed with a set of round cylinders.
The upper part of the engine is the cylinder head. Bolted to the top of the block, it seals the tops of the cylinders. Pistons compress air and fuel against the cylinder head prior to ignition. The top of the piston forms the floor of the combustion chamber. A rod connects the bottom of the piston to the crankshaft. Lubricated bearings enable both ends of the connecting rod to pivot, transferring the piston’s vertical motion into the crankshaft’s rotational force, or torque. The pistons’ motion rotates the crankshaft at speeds ranging from about 600 to thousands of revolutions per minute (rpm), depending on how much fuel is delivered to the cylinders.
Fuel vapor enters and exhaust gases leave the combustion chamber through openings in the cylinder head controlled by valves. The typical engine valve is a metal shaft with a disk at one end fitted to block the opening. The other end of the shaft is mechanically linked to a camshaft, a round rod with odd-shaped lobes located inside the engine block or in the cylinder head. Inlet valves open to allow fuel to enter the combustion chambers. Outlet valves open to let exhaust gases out.
A gear wheel, belt, or chain links the camshaft to the crankshaft. When the crankshaft forces the camshaft to turn, lobes on the camshaft cause valves to open and close at precise moments in the engine’s cycle. When fuel vapor ignites, the intake and outlet valves close tightly to direct the force of the explosion downward on the piston.
Crash/Safety Features
What actually happens in a collision? The first part of that answer is that there are two collisions. The first collision occurs when the vehicle runs into another object. The second collision is when the occupant(s) hit the inside of the car. Neither a seat belt nor an air bag can do anything about the first collision, but they can be a great help to you in the second collision. They can minimize the impact between you and the interior of the car. Safety belt use is more than a personal right. Injuries and fatalities resulting from motor vehicle accidents are reflected in the rising costs of auto and health insurance, and costs to employers in the form of lost days at work. The taxpayer also loses by having to support emergency medical response teams and social programs for the disabled. Excuses, excuses! 1. "Seat belts are too uncomfortable." Of course, in a car accident -- without your seat belt -- you would smash into the steering column, slam into the dashboard, or crash through the windshield. This too, can be very uncomfortable. 2. "Seat belts wrinkle my clothes." Sometimes. Sitting also wrinkles clothes. Wearing clothes wrinkles clothes. Flying through a windshield REALLY wrinkles clothes. 3. "Only nerds wear seat belts." Really? It turns out that -- without seat belts -- nerds, jocks, cheerleaders, "A" students and average students would all fly through the windshield at the same rate. 4. "I'm a good driver." Nice as that is, good drivers can get hit by bad drivers, drunk drivers, or other good drivers with mechanical failures. Very few people intend to have accidents. 5. "Seat belts restrict my freedom of movement." This is true. Without your seat belt, you have all the freedom in the world -- to crash into your windshield, to slam into your car's interior, or to be thrown from your car and slide along the pavement. Freedom is great. 6. "It's too embarrassing to ask friends to use their seat belts." In 1984, 46,000 people died in car accidents. That same year, not one person died of embarrassment. Safety in car design was recognized as being important even in the earliest cars. In recent years, however, it has become a fundamental subject in its own right. Active safety measures have been designed to reduce the likelihood of a car being involved in an accident in the first place, while passive safety measures assume that a collision is inevitable and then aim to reduce the severity of the injuries to the road users involved. Until the late 1800's the British had a 2 mph speed limit for cars. There was an excellent reason for this. It was also required, for safety's sake, that each car carry two passengers with a third person walking in front. The job of the third person was to walk in front of the car to warn everyone that it was coming!
Brake Bands
A brake band is made of steel, and has a friction lining. One end of the band is attached a servo actuating rod. A servo actuating rod is a hydraulic piston (a cylinder with a piston inside it) that is open at one end to allow oil to flow in. The piston is normally in the released position because it's kept that way by a spring. However, when pressurized oil is sent to the cylinder, the oil forces the piston forward. This causes the brake band to tighten, and this locks the brake.
BRAKE
Brakes enable the driver to slow or stop the moving vehicle. The first automobile brakes were much like those on horse-drawn wagons. By pulling a lever, the driver pressed a block of wood, leather, or metal, known as the shoe, against the wheel rims. With sufficient pressure, friction between the wheel and the brake shoe caused the vehicle to slow down or stop. Another method was to use a lever to clamp a strap or brake shoes tightly around the driveshaft.
A brake system with shoes that pressed against the inside of a drum fitted to the wheel, called drum brakes, appeared in 1903. Since the drum and wheel rotate together, friction applied by the shoes inside the drum slowed or stopped the wheel. Cotton and leather shoe coverings, or linings, were replaced by asbestos after 1908, greatly extending the life of the brake mechanism. Hydraulically assisted braking was introduced in the 1920s. Disk brakes, in which friction pads clamp down on both sides of a disk attached to the axle, were in use by the 1950s.
An antilock braking system (ABS) uses a computer, sensors, and a hydraulic pump to stop the automobile’s forward motion without locking the wheels and putting the vehicle into a skid. Introduced in the 1980s, ABS helps the driver maintain better control over the car during emergency stops and while braking on slippery surfaces.
Automobiles are also equipped with a hand-operated brake used for emergencies and to securely park the car, especially on uneven terrain. Pulling on a lever or pushing down on a foot pedal sets the brake.
Disc and Drum Brakes Disc and drum brakes create friction to slow the wheels of a motor vehicle. When a driver presses on the brake pedal of a vehicle, brake lines filled with fluid transmit the force to the brakes. In a disc brake, the fluid pushes the brake pads in the caliper against the rotor, slowing the wheel. In a drum brake, the fluid pushes small pistons in the brake cylinder against the hinged brake shoes. The shoes pivot outward and press against a drum attached to the wheel to slow the wheel.
A brake system with shoes that pressed against the inside of a drum fitted to the wheel, called drum brakes, appeared in 1903. Since the drum and wheel rotate together, friction applied by the shoes inside the drum slowed or stopped the wheel. Cotton and leather shoe coverings, or linings, were replaced by asbestos after 1908, greatly extending the life of the brake mechanism. Hydraulically assisted braking was introduced in the 1920s. Disk brakes, in which friction pads clamp down on both sides of a disk attached to the axle, were in use by the 1950s.
An antilock braking system (ABS) uses a computer, sensors, and a hydraulic pump to stop the automobile’s forward motion without locking the wheels and putting the vehicle into a skid. Introduced in the 1980s, ABS helps the driver maintain better control over the car during emergency stops and while braking on slippery surfaces.
Automobiles are also equipped with a hand-operated brake used for emergencies and to securely park the car, especially on uneven terrain. Pulling on a lever or pushing down on a foot pedal sets the brake.
Disc and Drum Brakes Disc and drum brakes create friction to slow the wheels of a motor vehicle. When a driver presses on the brake pedal of a vehicle, brake lines filled with fluid transmit the force to the brakes. In a disc brake, the fluid pushes the brake pads in the caliper against the rotor, slowing the wheel. In a drum brake, the fluid pushes small pistons in the brake cylinder against the hinged brake shoes. The shoes pivot outward and press against a drum attached to the wheel to slow the wheel.
Bleeder Valves
Since the brake system is filled with fluid, it must be occasionally "bled" or the old fluid released in order to install new fluid. It is also occasionally necessary to remove air bubbles that get into the system if any of the parts are changed. Disc brakes, drum brakes and all hydraulic brakes have bleeder valves next to the slave pistons. These are opened when the system is being bled and brake fluid flows out as well as air bubbles. When the brake fluid is coming out without any air bubbles, the mechanic seals the bleeder valve and tops off the brake fluid reservoir. Bleeder valves can also be found on the side of the reservoir. These are used for the same purpose; getting air bubbles out of the master cylinder assembly. If you have air bubbles in your fluid, your pedal will feel softer than normal, and braking power will be reduced, so it is a good idea to have your brakes bled and the fluid changed according to your owner's manual.
Air Compressor.
Air Compressor, also air pump, machine that decreases the volume and increases the pressure of a quantity of air by mechanical means. Air thus compressed possesses great potential energy, because when the external pressure is removed, the air expands rapidly. The controlled expansive force of compressed air is used in many ways and provides the motive force for air motors and tools, including pneumatic hammers, air drills, sandblasting machines, and paint sprayers. See Compressed Air.
Air compressors are of two general types: reciprocating and rotating. In a reciprocating, or displacement, compressor which is used to produce high pressures, the air is compressed by the action of a piston in a cylinder. When the piston moves to the right, air flows into the cylinder through the intake valve; when the piston moves to the left, the air is compressed and forced through an output-control valve into a reservoir or storage tank.
A rotating air compressor used for low and medium pressures, usually consists of a bladed wheel or impeller that spins inside a closed circular housing. Air is drawn in at the center of the wheel and accelerated by the centrifugal force of the spinning blades. The energy of the moving air is then converted into pressure in the diffuser, and the compressed air is forced out through a narrow passage to the storage tank.
As air is compressed it is also heated. Air molecules tend to collide more often with each other in a smaller space, and the energy produced by these collisions is evident as heat. This heat is undesirable in the compression process, so the air may be cooled on the way to the reservoir by circulating air or water. For high-pressure compressed air, several stages of compression may be employed, with the air being further compressed in each cylinder and cooled before each stage.
also Heating, Ventilating, and Air Conditioning; Heat Transfer; Pump.
TWO-STROKE ENGINES
By suitable design it is possible to operate an Otto-cycle or diesel as a two-stroke or two-cycle engine with a power stroke every other stroke of the piston instead of once every four strokes. The power of a two-stroke engine is usually double that of a four-stroke engine of comparable size.
The general principle of the two-stroke engine is to shorten the periods in which fuel is introduced to the combustion chamber and in which the spent gases are exhausted to a small fraction of the duration of a stroke instead of allowing each of these operations to occupy a full stroke. In the simplest type of two-stroke engine, the poppet valves are replaced by sleeve valves or ports (openings in the cylinder wall that are uncovered by the piston at the end of its outward travel). In the two-stroke cycle, the fuel mixture or air is introduced through the intake port when the piston is fully withdrawn from the cylinder. The compression stroke follows, and the charge is ignited when the piston reaches the end of this stroke. The piston then moves outward on the power stroke, uncovering the exhaust port and permitting the gases to escape from the combustion chamber.
The general principle of the two-stroke engine is to shorten the periods in which fuel is introduced to the combustion chamber and in which the spent gases are exhausted to a small fraction of the duration of a stroke instead of allowing each of these operations to occupy a full stroke. In the simplest type of two-stroke engine, the poppet valves are replaced by sleeve valves or ports (openings in the cylinder wall that are uncovered by the piston at the end of its outward travel). In the two-stroke cycle, the fuel mixture or air is introduced through the intake port when the piston is fully withdrawn from the cylinder. The compression stroke follows, and the charge is ignited when the piston reaches the end of this stroke. The piston then moves outward on the power stroke, uncovering the exhaust port and permitting the gases to escape from the combustion chamber.
Monday, August 3, 2009
Turbo Charger How It Works
The turbocharger is bolted to the exhaust manifold of the engine. The exhaust from the cylinders spins the turbine, which works like a gas turbine engine. The turbine is connected by a shaft to the compressor, which is located between the air filter and the intake manifold. The compressor pressurizes the air going into the pistons.
The exhaust from the cylinders passes through the turbine blades, causing the turbine to spin. The more exhaust that goes through the blades, the faster they spin.
On the other end of the shaft that the turbine is attached to, the compressor pumps air into the cylinders. The compressor is a type of centrifugal pump -- it draws air in at the center of its blades and flings it outward as it spins.
In order to handle speeds of up to 150,000 rpm, the turbine shaft has to be supported very carefully. Most bearings would explode at speeds like this, so most turbochargers use a fluid bearing. This type of bearing supports the shaft on a thin layer of oil that is constantly pumped around the shaft. This serves two purposes: It cools the shaft and some of the other turbocharger parts, and it allows the shaft to spin without much friction.
There are many tradeoffs involved in designing a turbocharger for an engine. In the next section, we'll look at some of these compromises and see how they affect performance.
Valve Seals
The valve seal is a unit that goes over the end of the valve stem. It keeps excess oil from getting between the valve guide and the valve stem.
Shocking Developments
The first electric-powered road vehicle is believed to have been built in Scotland about 1839 by Robert Anderson, but it, along with others within the next several years, were generally unsuccessful. The steamer had to wait for a boiler to build up pressure and was very noisy besides. The concept of an electrical engine that could start immediately and run quietly was very attractive at that time. There were disadvantages, however. Electric batteries were heavy, bulky, unreliable, and needed recharging after a short run. In 1880, there was a general improvement in the development of longer-lasting batteries. There still existed, however, excessive weight and bulk of the batteries and a need for frequent rechargings, although electric cabs appeared on the streets of London in the late 1800s. Steamers and electric vehicles gained only restricted acceptance on the continent as well. In France, the electric had a shining, brief hour of public acclaim when Camille Jenatzy, driving a Jeantaud electric, pushed the cigar-shaped vehicle to a record of sixty miles per hour on April 29, 1899. The high-speed run, however, burned out the specially fabricated batteries and the interest in electrics died almost as soon as the cheers of the attending public. It was in America that steamers and electric cars gained their most sustained measure of success. Eventually twenty different U.S. car companies would produce electrics; and in the peak of popularity, 1912, nearly 35,000 were operating on American roads. But even America could not shake the limitations of the bulky batteries and the short ranges between recharging. Steamers were actually more popular. More than 100 American plants were making steamers, the most famous of which were the Stanley brothers factory in Newton, Massachusetts. The "Stanley Steamer" had the affectionate nickname, "The Flying Teapot," and with good reason. In 1906, a Stanley Steamer was clocked at 127.6 miles per hour on the sands of Ormond Beach, Florida. In spite of this, the steamers, along with the electrics, were only living on borrowed time. Experiments were being made on an automobile powered by a gasoline-fueled, internal-combustion engine, and the steamers and electrics would not survive the impact of the coming collision. Internal-combustion automobiles did not just burst forth on the scene all of a sudden to crowd the electrics and steamers off the road. The theories of internal-combustion engines had been on the way ever since 1860, when Etienne Lenoir applied to the authorities in Paris for a patent on his invention, an internal-combustion engine powered by coal gas. Two years later, Lenoir hooked his engine to a carriage, and, although it was crude, it worked. It worked so poorly and so slowly (about one mile an hour), however, that he became discouraged and abandoned his efforts. In 1864, a resourceful Austrian in Vienna, Siegfried Marcus, built a one-cylinder engine that incorporated a crude carburetor and a magneto arrangement to create successive small explosions that applied alternating pressure against the piston within the cylinder. Bolting his engine to a cart, Siegfried geared the piston to the rear wheels, and while a strong assistant lifted the rear of the cart off the ground, Siegfried started the engine. The wheels began to turn and continued to turn with each successive "pop." Marcus signaled the assistant to lower the cart and watched it burp along for about 500 feet before it ran out of fuel. Ten years later, he built the new, improved version of his motorcar, and then, mysteriously washed his hands of the entire thing, saying it was a waste of time. (The second model, which is preserved in an Austrian museum, was refurbished and taken for a test run in Vienna in 1950. It reached a top speed of ten miles per hour on level ground.) Although Lenoir and Marcus did not have the grit and determination to pursue their enterprises, they made some valuable contributions to the theory of internal-combustion engines. It would be overstating the case to credit them with the creation of the internal-combustion automobile, however.
Semiconductors and Diodes
Semiconductors are made from material somewhere between the ranges of conductors and nonconductors. Semiconductors, basically, are designed to do one of three things: (1) stop the flow of electrons, (2) start the flow of electrons, or (3) control the amount of electron flow. A semiconductor diode is a two-element solid state electronic device. It contains what is termed a "P" type material connected to a piece of "N" material. The union of the "P" and "N" materials forms a PN junction with two connections. The "anode" is connected to the P material; the "cathode" is connected to the N material. A diode is, in effect, a one-way valve. It will conduct current in one direction and remain non conductive in the reverse direction. When current flows through the diode, it is said to be "forward biased." When current flow is blocked by the diode, it is "reverse biased." When a diode is reverse biased, there is an extremely small current flow; actually, the current flow is said to be "negligible." When the P and N are fused together to form a diode, it can be placed in a circuit. The P material is connected to the positive side of the battery and the N material is connected to the negative side of the battery. Connected in this manner, current will flow. If connected in the reverse manner, current will not flow.
Worm and Tapered Peg Steering
The manual worm and tapered peg steering gear has a three-turn worm gear at the lower end of the steering shaft supported by ball bearing assemblies. The pitman shaft has a lever end with a tapered peg that rides in the worm grooves. When the movement of the steering wheel revolves the worm gear, it causes the tapered peg to follow the worm gear grooves. Movement of the peg moves the lever on the pitman shaft which in turn moves the pitman arm and the steering linkage.
Worm Gear
A "worm gear" is a shaft with very coarse thread, which is designed to operate or drive another gear or a portion of a gear. The special shape of the gear allows the rotation direction to be turned when the gears engage with minimal friction. An example is found inside the steering box, where the steering shaft turns a worm gear that is screwed into a large nut. The nut moves back and forth on friction-reducing ball bearings, which are continuously recirculated by dropping into the nut's bored channels and emerging at the opposite side. Power to move the nut comes from pressurized fluid entering from a pump through rotary valves that open in response to the steering wheel. The worm gear engages the cross shaft through a roller or by a tapered pin.
Wires and Cables
Wires and cables are conductors of electricity. Usually, they are made of annealed copper and are used to carry electricity to the various electrical devices and equipment on passenger cars and trucks. Wires and cables must be the right size for the application and must have proper insulation. If the wire or cable is too small in cross section or too long for its size, its resistance will be too great and valuable voltage will be lost. This will then result in poor operation of the electrical device in the connecting circuit. Wire size and length determines the resistance of the wire. Wire and cable sizes are expressed by a gauge number, which indicates the cross-sectional area of the conductor. The cross-sectional area of the wires is given in metric size or circular mils. The diameter is given in decimals of an inch. A circular mil is a unit of area equal to the area of a circle one mil in diameter. A mil is a length unit equal to .001 inches. The larger the diameter of the wire or cable, the smaller the gauge size number. Cables are made of several strands of wire. The cross-sectional area is equal to the circular mil area of a single strand times the number of strands. Special gauges are available for measuring the gauge size of wires and cables. Many multi-purpose electrician's pliers feature wire size holes for stripping, cutting, and crimping operations. When comparing cables, consider that the external diameter of insulated wire or cable has nothing to do with its current-carrying capacity. Thick insulation will make a small gauge wire look much larger. It is important that only the size of the metal conductors are compared.
Windshield Wipers
There are three types of motors that can be used for windshield wipers. The permanent "magnet" motor has two ceramic magnets that are cemented to the field frame and does not use field windings. It needs less energy than the other types of motor design, but the switch must be wired in series, creating many areas of resistance. The "shunt wound" motor provides a very consistent speed, but doesn't provide much torque upon starting. The "compound" motor wiper has a strong starting torque and provides consistent speed, but it is the most expensive. Most cars have an intermittent wiper system, which permits the driver to select a delayed wipe that operates only every few seconds. A representative wiper/washer unit is the wiper assembly, which incorporates a depressed park system that places the wiper blades below the hood line in the parked position. The relay control uses a relay coil, relay armature, and switch assembly. It controls starting and stopping of the wiper through a latching mechanism. An electric washer pump is mounted on the gear box section of the wiper. It is driven by the wiper unit gear assembly.
Windshield Washers
All cars use an electric pump-operated windshield washer with a positive displacement washer pump. On some, the motor is placed in the washer reservoir, while on others, it is driven by a wiper motor. When the pump is attached to the wiper motor, the four lobe cam starts a spring-loaded follower, but the pump does not operate all the time that the wiper motor is running. This is because the pumping mechanism is locked out and pumping action occurs. A plunger is pulled toward the coil, allowing the ratchet pawl to engage the ratchet wheel, which begins to rotate, one tooth at a time. Each lobe of the cam starts the follower. The follower moves the piston actuator plate and piston away from the valve assembly and compresses the piston spring, creating a vacuum in the pump cylinder through the intake valve. As the high point of each cam lobe passes the follower, the piston spring expands, forcing the piston toward the valves. This pressurizes the washer solution so it flows out the exhaust valves to the spray nozzles.
Windshield
Up until 1935 many cars had hinged windshields that could be folded on the hood of the car or opened up. Today, most windshields are stationary. They are fixed in place with a weather-strip made of rubber. The strip has a groove on the inside and a groove on the outside. The inside groove holds the glass; the outside groove holds the metal rim of the windshield opening in place. The glass "floats" in a plastic sealant that is spread out between the edge of the glass and the frame of the windshield. Windshields are made of laminated safety plate glass, which is a sandwich of glass and clear plastic. The plastic acts as a soft, protective barrier, keeping the glass in place, if it is struck during a collision. The glass sticks to the plastic to eliminate glass from flying around the interior and injuring someone. Safety glass for windscreens was one of the first passive safety devices introduced into cars in the 1930s, but its use remains a controversial question. North America and Scandinavia favor a laminated glass, which consists of two sheets of annealed glass, separated by a layer of transparent plastic. The rest of Europe and Japan favor toughened glass because it is cheaper. This type is a single sheet of glass which is heat strengthened, and which on impact fractures into small cubic fragments without very sharp edges. In recent years, laminated glass has been improved by changes in the properties of the plastic interlayer. Research has demonstrated that this new laminated glass is about 4 times safer than toughened glass, but because it is more expensive, controversy continues as to whether or not toughened glass windscreens should be banned by legislative action and replaced by laminated glass. Recent developments have combined the benefits of both laminated and toughened material in that a laminated construction is used, but the sheet next to the inside of the car is made of toughened glass.
Window Winding Mechanisms
There are two types of window winding mechanisms; hand cranked and power. Hand cranks work two ways. With "window winders," the crank turns a "sector gear" that pivots a pair of arms. The arms raise the "window carrier" and the glass. Some cars have fixed glazing in the rear doors so that the window cannot go up or down. The other type of window crank is a tape mechanism. It winds up a ladder-like tape made of plastic links. The plastic links are wound on to or off a spool to raise or lower the glass. The tape mechanism was introduced in 1980 GM cars. It saves weight and space. Its parts will not corrode when rainwater gets into the door, and it needs no lubrication. First introduced in 1946, power windows use a small electric motor inside the door. The motor turns the crank that raises the window. Door and vent windows are made of laminated "safety" plate glass, which is a sandwich of glass and clear plastic. The plastic acts as a soft, protective barrier, keeping the glass in place, if it is struck during a collision. The glass sticks to the plastic even when shattered.
Why Is It Called An "Automobile"?
First let us consider the name, "automobile." Now, a "car" could have been called anything and, sometimes, it is. Oliver Evans applied for a U.S. patent in Philadelphia in 1792 on a steam land carriage, which he called the "oruktor amphibolos!" We could have been strapped with that name forever, if it weren't for more reasonable individuals working on the same concept. Martini was a 14th Century Italian painter, who had been trained in engineering. He designed (on paper) a man-propelled carriage, mounted on four wheels. Each wheel was powered by a hand-turned capstan arrangement. Gearing was also provided to transmit the rotation of each capstan to the wheel below. It may have looked good on paper, but the four turners of the capstans couldn't have kept it up for long before they fell over with exhaustion. It is lucky for us that Martini did not name his invention after himself, as many inventors do. If he had, and the word had survived to the present, it might be a little confusing. If we were offered a "Martini," we might not know whether to drive it or drink it! (Representatives of MADD and SADD would probably tell us to park it!) We could be reading headlines like: ORUKTOR ACCIDENT TAKES THREE LIVES or UNITED MARTINI WORKERS ON STRIKE. The really historical (and fortunate) aspect of Martini's design is the name that he gave it: "automobile," from the Greek word, "auto," (self) and the Latin word, "mobils," (moving). "Car," on the other hand, comes from an ancient Celtic word, "carrus," meaning cart or wagon. George B. Selden, an attorney in Rochester, New York, applied for, and finally received, a patent for a "road machine" in 1879. The Duryea brothers (1895) called their products "motor wagons." In 1896, Henry Ford introduced an experimental car labeled the "Quadricycle." Newspapers used words like autometon, motor-vique, oleo locomotive, autokenetic, buggyaut, motor carriage, autobaine, automotor horse, diamote, motorig, mocole, and, of course, the horseless carriage. In 1895, H. H. Kohlsaat, publisher of the Chicago Times-Herald, offered a $500.00 prize for the best name for the motorized vehicles of the day. The judges picked "motorcycle" as the winner. "Quadricycle" was a favorite, as was "petrocar." The word "automobile" wasn't even in the running! But in 1897, The New York Times prophesied, "...the new mechanical wagon with the awful name -- automobile...has come to stay..." Many of the words that are associated with automobiles are derived from the French; i.e, garage, chauffeur, limousine, and chassis are just some examples.
Where Did The Idea Come From?
No one person can be credited for the invention of the automobile that you are driving today. It has developed bit by bit from the ideas, imagination, fantasy, and tinkering of hundreds of individuals through hundreds of years. In the 13th-century, the English philosopher-scientist, Roger Bacon, said that "cars can be made so that without animals they will move with unbelievable rapidity." Oh, Roger, if you only knew! Bacon was positive that these vehicles had existed in ancient times, but he didn't know what propelled them. The Greeks apparently had their own Olympic assembly line. In the "Iliad," Haephestus (the Roman "Vulcan"), was the god of fire and invention. When he had time off from making thunder bolts and beautiful jewelry for the vain goddesses, he built three-wheeled vehicles, which moved from place to place under their own power. Homer says they were "self-moved, obedient to the gods," and would Homer lie? The really remarkable thing about this is that even as far back as the Homeric era (8th-9th (?) century B.C.), man had already imagined automobiles. The motorized vehicle is, indeed, a prime example of creeping development; i.e., invention through slow accumulation of bits and pieces over a time so long that it is hard to pin down its origin. Thomas Russell Ybarra, in this century, wrote rhyming doggerel which pointed to the automobile as a Roman invention. Those who care to can point to two 15th-century Italians: Francesco di Giorgio Martini (whose concept has been presented in another section) and Leonardi Da Vinci. Da Vinci conceived an armor-plated war vehicle, the propulsion system of which is much like that of Martini's. This particular concept of Da Vinci did not contribute anything of value, not even a name, as did Martini's. The important thing to remember is the automobile is not some recent idea that popped up in the 19th-century, or the 18th, or even the 14th. It is a creation that has charmed imagination and inventiveness before man was able to conceive how to make it go. Perhaps that is why Homer placed it in the hands of the gods.
When The Car Doesn't Work
BEFORE a car needs repairs, the owner should check the car's manual to see if maintenance is needed. Failure to care for the car, and ignoring the initial warning signs (funny noises, problems that "fix themselves", etc) will produce more extensive and costly damage in the long run. I. Starting Problems Problems encountered in starting are usually due to the condition of the battery (clicking noises, no sound or slow grinding). These problems can often be solved by jump starting or charging the battery. If there is no response after trying these cures, it will probably be necessary to get experienced help or have your car inspected and serviced by a professional. II. Moving Problems 1. Problems with the engine hesitating, cutting out, being weak, or having difficulty with the idling should all be carefully inspected by an experienced mechanic. Overheating may be due to a need for additional coolant in the radiator or a need to unload excess weight (as when pulling a trailer). Turn off all accessories; i.e., the air conditioner. If this doesn't help, get professional help. 2. Transmission problems should always be inspected for repair or adjustment by a professional mechanic. If the car is driveable, drive slowly and carefully to the nearest service facility. If in doubt about driving the car, call a tow truck. III. Stopping Problems: When the brakes fail to hold, or if they squeal, grab or drag, they should be inspected and cared for at a specialized brake shop. When the problem is due to worn tires, the tires should be replaced at once before damaging other, more expensive elements of the car.
Wheels
Wheels come in many different designs and usually fall into two categories: stamped sheet metal and machine castings. Some wheels are a combination of the two. Usually cast alloy wheels are higher priced, but have greater strength than stamped sheet metal wheels. Stamped sheet metal wheels are the most common, because they are less expensive to produce and are adequate for most uses. Some cars have wire wheels which consist of three basic components; inner rings, outer rings, and a series of spokes which connect the two. Cast aluminum wheels are very popular, magnesium wheels are also popular. Both are popular because they are light-weight and strong.
Wheelbase Balance
Another important factor when locating axles and spindles for wheel balance is the wheelbase measurement. Wheelbase is the distance between the center of the front wheel and center of the rear wheel. This distance (left front to left rear, right front to right rear with wheels in the straight ahead position) must be exactly the same on each side for proper weight balance. Correct wheelbase contributes to the ability of the car's rear wheel to follow directly in line with the front wheels (called "track"). Shorter wheelbases allow sharper turning radiuses, and longer wheelbases give a smoother ride and increased stability.
Wheel Well
The wheel well is either plastic or metal. Metal wheel wells are usually part of the body shell. Metal wheel wells strengthen the structure of the car because of their shape, and because they are strongly welded to the body shell. Most rear wheel wells are made of metal. Wheel wells are coated with a rock-proof, rubberized coating underneath, in order to prevent the rocks kicked up by the wheels from damaging the metal and making a lot of noise when they hit. Often the front wheel wells are made of plastic. This is because it is harder to mount the engine with the front wheel wells in place. Plastic wheel wells can be removed, and make it easier to mount the engine during the manufacturing of the car.
Wheel Lugs
Wheel lugs are the large bolts that go through the wheel rim and secure it to the wheel hub. They are pressed into the hub from the inboard side so they cannot pull out when tightened. The Lug nuts thread onto the wheel lugs, clamping the wheel rim between the hub and lug nuts. It is extremely important that the wheel lug nuts are securely tightened! If they are not -- your wheel will come off! Over- tightening is also a bad idea; it can prevent you from being able to change a flat tire.
Wheel Balance and Unbalance
It is important to check to see that the wheel and tire assemblies are in balance before aligning the vehicle. "Static" balance is the equal distribution of weight around the wheel and tire assembly. "Dynamic" balance is the equal distribution of weight on each side of the vertical centerline of the wheel and tire assembly. "Unbalance" (or imbalance) exists when the weight is distributed unequally around the horizontal axis of the wheel and tire assembly. Unbalance can exist in the tire, wheel, brake drum or rotor, or even in the hub. It also occurs in any combination of these components. Unbalance can be detected with the aid of special equipment, which usually indicates the proper location for wheel weights to restore the proper balance. Even with regular maintenance, however, uneven tire wear can result from drivers' habits, such as side wear from excessive cornering speeds. To counteract uneven wear that leads to unbalance, the tire industry recommends that tires should be rotated every six to eight thousand miles.
Wheel Alignment
Aligning a vehicle's front wheels is the job of balancing the steering angles with the physical forces being exerted. The steering angles are; caster, camber, toe-in, steering axis inclination, and toe-out on turns. The physical forces are gravity, momentum, friction, and centrifugal force. Since so many factors are involved in front wheel alignment, it is also called front end alignment, steering alignment, steering balance, or steering geometry. Alignment is more than just adjusting the angularity of the front wheels. With steadily increasing production of front wheel drive vehicles with independent rear suspension, four wheel alignment is often required. For ideal wheel alignment, certain conditions would have to be met. Both front tires will be the same brand, size, and type. Each will have the same degree of tread wear, and be inflated with the same pressure. Each wheel is properly and equally adjusted for angularity, each tire will maintain the same area of tread contact on a smooth road surface. Obviously, it is impossible to maintain all these requirements. The steering control rods are used to adjust toe-in and toe-out. The upper and/or lower control arms are adjusted to affect the camber angle. Caster is usually not adjustable. With all the weight balance factors to be checked out and corrected, it is obvious that wheel alignment is more than just an adjustment of the steering angles. The whole theory of wheel alignment revolves around balanced weight distribution on the wheels and proper tire tread contact with the road surface while the vehicle is in motion.
Wheel (Slave) Cylinder
The wheel cylinder, also called the brake cylinder or slave cylinder, is a cylinder in which movable piston(s) convert hydraulic fluid pressure into mechanical force. The piston(s) within the cylinder move the brake shoes or pads against the braking surface of the drum or rotor. There is one cylinder (or more in some systems) for each wheel. The cylinder is usually made up of a single-bore cylinder casting, an internal compression spring, two pistons, two rubber cups or seals, two rubber boots to prevent entry of dirt and water, and a bleeder screw (valve). In drum type brakes, the wheel cylinder is fitted with push rods that extend from the outer side of each piston through a rubber boot, where they bear against the toe end of each brake shoe. In disc brakes, the wheel cylinder is part of the caliper. As the brake pedal is depressed, it moves pistons within the master cylinder, forcing hydraulic brake fluid through the brake lines and into cylinders at each wheel. The fluid under pressure causes the wheel cylinders' pistons to move, which forces the shoes or pads against the brake drums or rotors. Two-way pressure is applied when the wheel cylinder is activated. Brake fluid enters the center of the cylinder, forcing the pistons apart. Pushrods at the piston ends then apply equal pressure to the brake shoes. A return spring pulls the pistons together when pressure is released.
Weight Balance on The Springs
The springs control the up-and-down motion of the car and so, the height of the car above the road. If one or more of the springs is collapsed or broken, it causes an unbalanced distribution of weight. This unbalance creates a lopsided appearance, puts an added strain on the related parts, and changes the angularity of the front wheels. This condition may also occur when the load is distributed unequally. In fact, anything that changes the ratio of weight on the springs will have a definite bearing on the alignment angles and on the area of tire-to-road contact. This can wear tires unevenly, making it necessary to replace them prematurely.
Water Pump
Water pumps come in many designs, but most include a rotating impeller, which forces the coolant through the engine block. In most rear wheel drive cars, the fan is installed on the end of the water pump shaft. Many water pumps have a spring-loaded seal to avoid leakage of water around the pump shaft. Modern pumps are fitted with pre-packed ball bearings, which are sealed at each end to eliminate the need for lubrication. Impeller type water pumps must turn rapidly to be efficient, and worn or loose drive belts can permit slippage which is not easily detected.
Water (Coolant) Jackets
When our bodies feel cold, we put on a jacket. Our car engines wear permanent jackets for the opposite reason-- to keep cool! The water jacket is a collection of passages within the block and head. These passages let the coolant circulate around the "hot spots" (valve seats and guides, cylinder walls, combustion chamber, etc.) in order to cool them off. The engine block is actually manufactured in one piece with the water jackets cast into the block and cylinder head. At normal operating temperature, the water pump forces the coolant through the head gasket openings and on into the water jackets in the cylinder head. It flows around in there, cooling everything off by absorbing the heat. After doing its thing, the coolant flows through the upper hose to the radiator where it releases the heat. Then, the water pump sends it back down into the engine's water jackets to continue the cooling process. On the sides of the engine are "freeze" or "expansion" plugs, which are sheet metal plugs pressed into a series of holes in the block. These are designed to hold the pressure of the cooling system, but to pop out if the coolant in the block ever freezes.
Wankel Rotor
The rotor within a rotary engine consists of three basic parts. One is the rotor itself which has cavities in it that serve as compression chambers. The second part consists of seals; these are strips of metal mounted at each point of the rotor. The third principal component of the rotor is the ring gear. The ring gear engages the fixed gear that is mounted to the side of the engine block. Since the fixed gear and the ring gear are engaged as the rotor rotates, a flip-flopping motion of the rotor (much like a hula-hoop) is caused as it goes around the fixed gear. Within the rotor is the eccentric shaft that turns independently of both the rotor and the fixed gear. This serves basically the same purpose as the crankshaft of an engine, and it works in much the same way. As the rotor is flipped around the fixed gear, it turns the eccentric shaft at half the rotor's rotating speed. Due to the imperfect nature of the seals on the rotor as compared to the rings on a piston engine, rotary engines tend to pollute more than piston engines. However, with the development of new seal technology, improvements are being made in this area.
Voltage Regulator
The alternator produces the electricity needed to charge the battery and to operate electrical equipment. Its output, however, continues to rise as its speed increases, so the charging system must be provided with a voltage regulator. Voltage regulators are in their third phase of development. First, there were electromagnetic voltage regulators, which were used in both dc and alternator charging systems. Then came electronic voltage regulators, which are still used in most late model applications. They are solid state devices, which did away with wire-wound coils, contact points, and bimetallic hinges. They appear to be more reliable, durable, and less affected by temperature change. Now, in some cars, the voltage regulator function has become part of the engine computer control system. Regardless of the kind, the voltage regulator controls voltage and current output of the alternator by automatically cutting resistance in or out of the field circuit to keep it in a safe value. Varying the resistance alters the amount of current passing through the field. When the battery becomes fully charged, the resistance is cut into the field circuit and the charging rate is decreased. Electromagnetic regulators, which are used on many dc generator charging systems, consist of three elements: cutout relay, current regulator, and voltage regulator. Others may use a cutout relay and a step-voltage control unit or a cutout relay with a vibrating voltage regulator or a combination of the cutout relay with a current-voltage unit. In electromagnetic regulators, the voltage regulator unit limits voltage output by controlling the amount of current applied to the rotating field. The field relay on these regulators connects the alternator field windings and voltage regulator windings directly to the battery. The conventional cutout relay unit has been eliminated by the diodes in the alternator. The current regulator has also been eliminated by the current-limiting characteristic of the alternator design. Basically, in a transistorized or an electronic regulator, the transistor is switched on and off to control the alternator field current. The frequency of switching depends on the alternator speed and accessory load, with the possibility that the on-off cycle may be repeated as often as 7000 times per second. The transistorized units have a voltage limiter adjustment. The electronic units are factory calibrated and sealed. They are also nonadjustable. When the ignition switch is turned off, the solid state relay circuit turns off the output stage, and turns off all current flow through the regulator. With that, there is no current drain on the battery. The field current overprotection stage protects the regulator against damage that could be caused by a "short" in the field circuit. Voltage regulator units have been replaced by functions with two engine computer modules on some late model Chrysler Corporation applications. The regulator functions are shared by circuits in the power and logic modules in the engine spark control computer. It is claimed that this prevents the possibility of "blowing" computer circuits if a charging system terminal is accidentally grounded. In operation, the field is turned on by a driver in the power module. The logic module also checks battery temperature as a means of determining and controlling alternator output voltage to control the amount of current allowed to pass through the alternator field windings.
Venturi
"Barrel" is a popular term for the carburetor throat. There is one venturi in each throat. A two-barrel carburetor has a primary venturi for part-load running and a secondary venturi for full-throttle; a four-barrel carburetor has two primary and two secondary venturis. The venturi tube is important in carburetion. A "venturi" is a tube with a restricted section. When liquid or air passes through the venturi tube, the speed of flow is increased at the restriction, and air pressure is decreased, creating an "increase in vacuum" (a reduction in ambient pressure). This causes fuel to be drawn into the barrel. The venturi action is used to keep the correct air-fuel ratio throughout the range of speeds and loads of the engine.
Variations in Resistance
The height of the fuel in a tank causes the sending unit to send variations in resistance, which changes the current to the dash unit coil so the pointer indicates the amount of fuel available.
Vapor Lock
Vapor lock is a condition in which fuel boils in the fuel system, forming bubbles which retard or stop flow of fuel to the carburetor.
Vane" Power Steering Pump
Several types of power steering pumps are in use. The "vane" pump uses a rotor with six to ten vanes which rotate in an elliptical pump ring. Fluid trapped between the vanes is forced out under pressure as the vanes move from the long diameter of the pump ring to the short diameter.
Valves
The valve's job is to open and close the valve ports. If the ports were always open, the fuel exploded in the combustion chamber would leave through the ports. The explosion has to be kept in the combustion chamber to push the piston down. The valves are set up to open and close at exactly the right moment. One lets the fuel mixture in and closes. After the fuel explodes and pushes the piston down, the other valve lets the exhaust out.
Valve Springs
The valve springs keep the valves closed tightly against their seats until the valve is opened by the cam. After the cam turns (releasing pressure), the valve springs close the valves.
Valve Ports
Valve ports are openings in the cylinder head. Intake ports let the fuel mixture into the cylinder head, and exhaust ports let the exhaust out.
Valve Lifter (Tappet)
The valve lifter is the unit that makes contact with the valve stem and the camshaft. It rides on the camshaft. When the cam lobes push it upwards, it opens the valve. The engine oil comes into the lifter body under pressure. It passes through a little opening at the bottom of an inner piston to a cavity underneath the piston. The oil forces the piston upward until it contacts the push rod. When the cam raises the valve lifter, the pressure is placed on the inner piston which tries to push the oil back through the little opening. It can't do this, because the opening is sealed by a small check valve. When the cam goes upward, the lifter solidifies and lifts the valve. Then, when the cam goes down, the lifter is pushed down by the push rod. It adjusts automatically to remove clearances.
Valve Guides
The valves are usually held in an upright position by the valve stem. The valve stem is the long straight side of the valve, like the stem of a flower. Holes are bored in the cylinder head for the valve stems. Worn valve guides allow oil to enter the combustion chamber and cause blue smoke in the exhaust.
Valve Cover
The valve cover covers the valve train. The valve train consists of rocker arms, valve springs, push rods, lifters and cam (in an overhead cam engine). The valve cover can be removed to adjust the valves. Oil is pumped up through the pushrods and dispersed underneath the valve cover, which keeps the rocker arms lubricated. Holes are located in various places in the engine head so that the oil recirculates back down to the oil pan. For this reason, the valve cover must be oil-tight; it is often the source of oil leaks. The valve cover is often distorted on older cars, because at some point the valve cover screws were over-tightened, bending the valve cover. This happens because the valve cover is made of very thin sheet metal and cannot withstand the force of an over-tightened bolt. One way to determine if your valve cover is bent is to remove the gasket and put the valve cover back on to the cylinder head. When the valve cover and cylinder head come into contact, the cover should sit flat. If it rocks, it is bent. Cast aluminum valve covers cannot be straightened, they need to be replaced. Sheet metal valve covers can be straightened. A symptom of a bent or leaking valve cover is a pinching of the valve cover gasket. This means that the gasket is sealing one area and not sealing another area. This condition produces a leak; oil could be leaking down the side of the engine. Some valve covers are hard to access, because they are covered with other engine parts. Chronic valve cover leakage can sometimes be fixed by using two gaskets glued together instead of using just one.
Vacuum from the Engine
Engine intake manifold vacuum is used for the braking effort in vacuum assisted power brakes. When you push the brake pedal down, the vacuum control valve lets the vacuum into one section of the booster unit. The atmospheric pressure moves a piston or diaphragm to provide the additional braking action.
Vacuum Valve (Vacuum Control Valve)
A power brake unit is made to take advantage of the vacuum the car's engine produces. A vacuum control valve allows vacuum from the engine into one side of the piston, and keeps normal atmospheric pressure on the other side. It is placed between the brake and the master cylinder piston.
Vacuum System (Importance of)
Engines run on a vacuum system. A vacuum exists in an area where the pressure is lower than the atmosphere outside of it. Reducing the pressure inside of something causes suction. For example, when you drink soda through a straw, the atmospheric pressure in the air pushes down on your soda and pushes it up into your mouth. The same principal applies to your engine. When the piston travels down in the cylinder it lowers the atmospheric pressure in the cylinder and forms a vacuum. This vacuum is used to draw in the air and fuel mixture for combustion. The vacuum created in your engine not only pulls the fuel into the combustion chamber, it also serves many other functions. The running engine causes the carburetor and the intake manifold to produce "vacuum power," which is harnessed for the operation of several other devices. Vacuum is used in the ignition-distributor vacuum-advance mechanism. At part throttle, the vacuum causes the spark to give thinner mixtures more time to burn. The positive crankcase ventilating system (PCV) uses the vacuum to remove vapor and exhaust gases from the crankcase. The vapor recovery system uses the vacuum to trap fuel from the carburetor float bowl and fuel tank in a canister. Starting the engine causes the vacuum port in the canister to pull fresh air into the canister to clean out the trapped fuel vapor. Vacuum from the intake manifold creates the heated air system that helps to warm up your carburetor when it's cold. The EGR valve (exhaust-gas recirculation system) works, because of vacuum, to reduce pollutants produced by the engine. Many air conditioning systems use the vacuum from the intake manifold to open and close air-conditioner doors to produce the heated air and cooled air required inside your vehicle. Intake manifold vacuum also is used for the braking effort in power brakes. When you push the brake pedal down, a valve lets the vacuum into one section of the power-brake unit. The atmospheric pressure moves a piston or diaphragm to provide the braking action.
Vacuum Pump
Several fuel pumps have a vacuum booster section that operates the windshield wipers at an almost constant speed. The fuel section then functions in the same way as ordinary fuel pumps. One difference is that the rotation of the camshaft eccentric in the vacuum pump also operates the vacuum booster section by actuating the pump arm, which pushes a link and the bellows diaphragm assembly upward, expelling air in the upper chamber through its exhaust valve out into the intake manifold. On the return stroke of the pump arm, the diaphragm spring moves the bellows diaphragm down, producing a suction in the vacuum chamber. The suction opens the intake valve of the vacuum section and draws air through the inlet pipe from the windshield wipers. When the wipers are not operating, the intake manifold suction (vacuum) holds the diaphragm up against the diaphragm spring pressure so that the diaphragm does not function with every stroke of the pump arm. When the vacuum is greater than the suction produced by the pump, the air flows from the windshield wiper through the inlet valve and vacuum chamber of the pump and out the exhaust valve outlet to the manifold, leaving the vacuum section inoperative. With high suction in the intake manifold, the operation of the wiper will be the same as if the pump were not installed. When the suction is low, as when the engine is accelerated or operating at high speed, the suction of the pump is greater than that in the manifold and the vacuum section operates the wipers at a constant speed. Some pumps have the vacuum section located in the bottom of the pump instead of in the top, but the operation is basically the same.
Vacuum Hoses and Motors
Vacuum lines are a series of hoses, or tubing, to the intake manifold. These hoses supply vacuum to various components of the engine, such as the emissions control system. Most air conditioning systems have vacuum motors to open and close the doors on the air conditioning ducts. A vacuum motor is just a small diaphragm with connecting rods to activate the valves of the system. They have the advantages of simplicity and quietness.
V-Belt (Fan Belt)
The fan (drive) belt wedges neatly into the different pulley grooves. The belt uses the tension and friction to turn the auxiliary devices. The fan belt is usually V-shaped, so it is also called a V-belt. The fan belt friction comes from the sides of the belt and the sides of the pulley grooves to transmit power from one pulley to the other through the belt. Since the sides of the belt are used for transmission of power, the sides have very large surface areas. The reason that the belt does not slip is because of the wedging action of the belt as it curves into the pulley grooves. Because your belts are so essential to so many parts of your engine, it is a very good idea to periodically check their condition. Check for cracking, splitting, or fraying, especially before summer. Also, check the tightness of the belt and have it adjusted according to your owner's manual specifications. Belts have a tendency to loosen with use. On the other hand, you don't want the belt to be too tight, or it will put too much pressure on the accessory bearings and cause them to die an early death. If a belt is over three years old, have it replaced even if it looks good.
Ups and Downs in Automotive Progress
As early as 1600, the Dutch, no strangers to wind power, had built a wind-powered, sail-mounted carriage. These carriages were reported to hold several passengers and move at speeds as high as twenty miles per hour. These tests were abandoned in favor of small windmills built onto the carriage, with mill vanes geared to the wheels. In either case, whether equipped with sails or windmills, they never caught on; mostly because they could not move except on the whim of a breeze. However, they were probably the first real land vehicles to move under power, other than that of animal or human muscle. While the Dutch dreamed in terms of the wind, others were thinking of other means of propulsion. In the 1700s, a Frenchman, Jacques de Vaucanson (no relation to the Roman god, Vulcan), built a vehicle which was powered by an engine based on the workings of a clock. What he neglected to calculate was that any clock which was capable of moving a vehicle with passengers would have to outweigh the load it was carrying. Even winding such a clock motor would take great time and greater effort than it was worth. Inventors in England, France, Germany and other countries worked on the idea of a compressed-air engine, but they were unable to find the solution to self-propulsion in this means. However, in their efforts, they contributed significant individual elements to the picture; elements like valves, pistons, cylinders, and connecting rods, and an emerging idea of how each of these elements related to the other. The first invention that can truly and logically be called an "automobile" was a heavy, three-wheeled, steam-driven, clumsy vehicle built in 1769 by Captain Nicolas-Joseph Cugnot, a French Army engineer. (Cugat was actually born in Switzerland, but the French don't want to hear about it.) This mechanism was slow, ponderous, and only moved by fits and starts. In tests, it carried four passengers at a slow pace - a little over two miles per hour - and had to stop every twenty minutes to build a fresh head of steam. It was, however, a self-powered, steerable, wheeled, people transporter, thereby demonstrating that the idea of mobilization was workable. Unhappily, Cugot's superiors were not men of vision and failed to appreciate the potential of his creation. To show him how they really felt, they disallowed him any funds for further development and transferred him to other duties. Since they had paid good money for this contraption, however, they preserved the vehicle, and it can still be seen in the Paris museum, where it is displayed with proper national pride. In the meantime, Great Britain, who believed themselves to be the masters of steam, had begun to believe that they could put this same steam on wheels. It was probably natural that they believed this; Thomas Savery, an English engineer, had given the world its first steam engine in 1698. This engine was crude (by our standards), inefficient, and blew up at intervals. Thomas Newcomen, an English blacksmith in 1711, turned out a better, less dangerous version of the engine. Then, in 1679, James Watt, a Scottish instrument maker, had patented a truly improved steam engine that became widely used in British mills, mines, and factories. Sir Isaac Newton, in 1680, conceived of the idea of a carriage propelled by a "rearwardly directed jet of steam." (It didn't amount to much at the time, but Sir Isaac's concept has become the means of rearwardly directed jets to provide the thrust for rockets to probe space.) Then, in 1801, an engineer in Cornwall, Richard Trevithick, built a road steamer, which was first tested in a Christmas Eve snowfall. Two years later, he built an improved model with drive wheels ten feet in diameter, which proved to be capable of sustained, reliable performance at speeds up to twelve miles per hour. Others were also working on steam propulsion in Germany, Denmark, Sweden, France, and the United States. The Evans vehicle, the "oruktor amphibolos" referred to earlier, was thirty feet long and weighed fifteen tons. It was really intended for dredging the harbor and was the world's first amphibious conveyance. On it first run in 1804, it clanked along on huge iron wheels, frightening Philadelphia onlookers out of their skivvies, before entering the Schuylkill River, where its propulsive energy was converted to a stern paddle wheel. Another American inventor, Richard Dudgeon, was experimenting with steam-mobiles. One was destroyed in a fire in 1858 in the famous Crystal Palace in New York City; another, built about ten years later, was banned from the streets by the civic leaders. Britain actually was where the steamers made their greatest impact. By the 1830s, they had set up a limited network which provided both passenger and freight service to a handful of cities. The public was awed, amused, and sometimes bitter. Some complained that the road steamers were noisy, which they were; and some complained that they were dangerous, which was occasionally true. But, as is natural, the loudest complaints came from vested interests, horse-drawn vehicles and railroads, who were afraid of losing business. Because of the pressure, in 1865, the British Parliament adopted the "Red Flag Act," which limited steamers to a speed of four miles an hour on the open road and to two miles an hour in the city. It required a crew of three men: one walking sixty yards ahead, with a red flag by day and a lantern at night, to warn of the vehicle's approach. Stymied by these restrictions, several British engineers turned their thoughts and attention to electricity as a promising alternative to steam. One can imagine that the automobile may have progressed very differently if not for these restrictions. It takes courage to effect revolutionary changes of any kind, and there were some formidable tinkerers in the horse-drawn carriage, nineteenth century; men like William Murdock, William Henry James, William Symington, Sir Goldsworthy Gurney and Walter Hancock, Charles Dallery, Etienne Lenoir, Amedee Bollee-Pere, Siegfried Marcus, Thomas Blanchard, William Janes, Nathan Read, Apollos Kinsey, Sylvester Roper, Carl Benz, and Gottlieb Daimler.
Upper and Lower Ball Joints
The upper and lower ball joints allow the spindle to rotate when steered, and move vertically to absorb road bumps at the same time. They are constructed of an inner ball which is bolted to the spindle, and a socket, which is bolted to the control arm. They are lubricated to prevent wear through their grease fittings.
Upper Return Spring
The pressure from the upper return spring forces the brake shoes back away from the drum, and forces the brake fluid back against the check valve when the brake is released.
Turbocharger Impeller
The impeller is a wheel like device with a series of curved fins or vanes. As the impeller whirls, the air is drawn in at the center and thrown off at the rim; the air is then forced into the passage at increased pressure. The impeller shaft connects the impeller with the turbine.
Turbocharger
A turbocharger, or supercharger, can boost engine power up to 40%%. The idea is to force the delivery of more air-fuel mixture to the cylinders and get more power from the engine. A turbocharger is a supercharger that operates on exhaust gas from the engine. Although turbochargers and superchargers perform the same function, the turbocharger is driven by exhaust gases, while the supercharger is driven by belts and gears. The turbocharger has a turbine and a compressor, and requires less power to be driven than a supercharger. The pressure of the hot exhaust gases cause the turbine to spin. Since the turbine is mounted on the same shaft as the compressor, the compressor is forced to spin at the same time, drawing 50%% more air into the cylinders than is drawn in without the turbocharger. This creates more power when the air-fuel mixture explodes. A turbocharged engine's compression ratio must be lowered by using a lower compression piston, since an excessive amount of pressure will wear on the piston, connecting rods, and crankshaft, and destroy the engine. All of these parts then, as well as the transmission, must be strengthened on a turbocharged engine or it will be torn apart by the increased horsepower.
Tubeless Tires
The tubeless tire is designed so that the air is sealed within the rim of the wheel and the tire casing. When an inner tube is used in the tire casing, the air is contained within the tube, while the casing is mainly used to protect the tube and provide traction. A tubeless tire is composed of a carcass, sidewall, and tread.
Tread of A Tire
The "tread" is the portion of the tire that comes in contact with the road. Treads are grooved traction surfaces around the circumference of the tire. The grooves and ribs formed during the manufacturing process are carefully engineered to provide good traction on wet and dry roads, control when cornering, minimum distortion at high speeds, reduced rolling resistance, and increased wear resistance. The sidewall and tread material is applied after the plies have been arranged and vulcanized in place. The tread and tire are designed to place the full width of the tread on the road when the tire is properly inflated. The variety of tread patterns is very broad. In fact, one publisher has produced a tread pattern identification guide that illustrates over 3000 patterns.
Tread Width in Wheel Balance
Tread width is a key measurement with respect to weight balance and rear wheel track. Tread width is the distance between the center points of the left tire tread and right tire tread as they come in contact with the road. While the front and rear wheels may have different tread widths, each front wheel must be the same distance from the centerline of the frame and each rear wheel must be the same distance from the centerline. This parallel relationship establishes a balance between the front and rear, and between the right and left. While this balance may not mean true equal weight at these points, it does mean that a balanced distribution of weight and stress has been acquired for the proper setting of front wheel angles.
Tread Wear Indicators
Tread wear indicators molded into modern tires serve as visual proof that the tire tread is approaching worn-out condition. These 1/2 inch indicators are located in several positions around the circumference of the tire. As long as the tread grooves are at least 1/16 deep, the grooves are unbroken. When tread depth reaches that point, the tread wear indicators will appear as solid strips across the tire. These strips interrupt tread continuity and are clearly visible upon inspection. The tire should be replaced when this occurs.
Transmission Tunnel
The transmission tunnel is a cone-shaped formation in the front of the floor pan. Its shape duplicates the transmission, but it is a little bit bigger and provides about two inches of clearance around the transmission. You won't find the transmission tunnel in front wheel drive cars, because the transmission is on the side of the engine completely under the hood. Only rear-wheel drive cars have transmission tunnels. A manual transmission tunnel has a hole in it to allow the shift linkage to be worked from inside the car. The shifter linkage goes through the transmission tunnel. A rubber boot on the shifter linkage stops dirt, dust and exhaust fumes from entering the passenger compartment. The rubber boot is mounted onto the transmission tunnel and fastened securely around the gearshift linkage. This arrangement is not necessary with an automatic transmission, because the shift linkage does not usually go through the transmission tunnel. The shift linkage in automatic transmission usually goes in front of the firewall from the base of the steering column.
Transmission Oil
The transmission needs lubrication to keep all of the gears and shafts running smoothly. This is accomplished by partially filling the transmission housing with thick transmission gear oil. When the gear gears spin, they fling the fluid around and lubricate all of the parts. Oil seals at the front and rear stop the fluid from leaking out of the housing. Fluid levels should be checked when you change your oil, or if you notice difficulties or differences in shifting. This can indicate that the level of fluid might be low.
Transmission Housing
The transmission housing is metal casting which is shaped to accommodate the gears within the transmission. On one end it has a flange that is bolted on to the back end of the clutch. On the other end, it has a seal where the output shaft protrudes going to the drive shaft.
Transmission Gears
Most cars have from three to five forward gears, and one reverse gear. The transmission changes the ratio of the engine speed and the wheels by connecting gears in various combinations. If a gear with 10 teeth is driving a gear with 20 teeth, the drive would be said to have a 2:1 ratio. First gear connects the engine power to the drive wheels via a pair of reduction gear sets, which gives increased power and reduced wheelspeed when the car is beginning to move. This means the engine is turning much faster than the output shaft, typically around a 4:1 ratio. Intermediate speeds are delivered by changing the gear ratio closer to 1:1. Final drive is usually accomplished by directly linking the input and output shafts, giving a 1:1 gear ratio. Using a moveable set of different sized gears, it's possible to get several degrees of torque output. The differential pinion, driven by the drive shaft, turns the ring gear, which acts like a single speed transmission. This further reduces RPM's and increases torque by a set ratio. Gears work exactly like levers. A small gear driving a larger one gives an increase in torque, and a decrease in speed, and vise-versa. Transmission gears are heat-treated, high quality steel. They have smooth, hard teeth, cut on precision machinery while red hot. There are many types of gear teeth, but most transmissions use spur and helical gears. Most of the gears are the helical type, because they last longer and are more quiet than spur gears. There has to be enough room (a few thousandths of an inch) between the gear teeth for lubrication, expansion, and any irregularities in size.
Transmission Fluid Dip Stick
The transmission fluid dip stick is a long metal rod that goes into the transmission. The purpose of the dip stick is to check how much transmission fluid is in the transmission. The dip stick is held in a tube; the end of the tube extends into the transmission. It has measurement markings on it. If you pull it out, you can see whether you have enough transmission fluid, or whether you need more by the level of fluid on the markings. Most manual transmissions do not have dipsticks, instead they use a filler hole which is at the same level as the correct oil level. When the oil is topped up or refilled, the mechanic simply adds oil until the filler hole's level is reached.
Transmission Fluid Cooler
As it is possible for the transmission fluid in automatic transmissions to overheat, causing reduction in performance and transmission damage, a transmission fluid cooler is a must. Manual transmissions (with the exception of racing car type vehicles) do not generally need transmission fluid coolers. The transmission fluid cooler is either a "borrowed" section of the engine's coolant radiator, or a separately mounted little tube with fins. The fluid is forced to flow through one of these arrangements, and consequently, cooled. Tube Type Transmission Fluid Cooler The tube type of transmission fluid cooler is usually located in the radiator's end cap. Because of its location it is immersed in and cooled by the engine's coolant. Then, when the transmission fluid passes through it, the fluid is cooled. Two metal tubes, called the transmission cooler lines, are attached to the outlet tank of the radiator and carry the fluid between the transmission and the fluid cooler. Auxiliary Transmission Fluid Cooler Vehicles that are factory equipped with packages for towing often also come equipped with an auxiliary fluid cooler. This cooler is mounted in front of the radiator and connected with the trans- mission. The auxiliary cooler is like a small engine coolant radiator. Both types of transmission fluid coolers ask the engine cooling system to do a bigger job; the tube type transfers the heat to the coolant. The auxiliary type, since it is mounted in front of the radiator, warms the air before it passes through the radiator.
Transmission Fluid
Transmission fluid is a special kind of oil used only for transmissions. It circulates through and lubricates the gears. Check your car's owner's manual for the type to use. No other type of oil should ever be used in your transmission.
Transistors and Resistors
A transistor is a solid state device used to switch and/or amplify the flow of electrons in a circuit. A typical automotive switching application would be a transistorized ignition system in which the transistor switches the primary system off and on. An amplifying application could be in a stereo system where a radio signal needed strengthening. A transistor is a three-element device made of two semiconductor materials. The three elements are called "emitter," "base," and "collector." The outer two elements (collector and emitter) are made of the same material; the other element (base) is different. Each has a conductor attached. The materials used are labeled for their properties: "P" for positive, meaning a lack of electrons. It has "holes" ready to receive electrons. "N" is for negative, which means the materials has a surplus of electrons. The movement of a free electron from atom to atom leaves a hole in the atom it left. This hole is quickly filled by another free electron. As this movement is transmitted throughout the conductor, an electric current is created from the negative to the positive. At the same time, the "hole" has been moved backward in the conductor as one free electron after another takes its place in a sort of chain reaction. "Hole flow" is from positive to negative. Current flow in a transistor, then, may be either electron movement or hole flow, depending on the type of material, and this determines the type of transistor it is as well. In most 12 volt systems, a resistor is connected in series with the primary circuit of the ignition coil. During the cranking period, the resistor is cut out of the circuit so that full voltage is applied to the coil. This insures a strong spark during cranking, and quicker starting is provided. The starting circuit is designed so that as long as the starter motor is in use, full battery voltage is applied to the coil. When the starter is not cranking, the resistance wire is cut into the circuit to reduce the voltage applied to the coil. If the engine starts when the ignition switch is turned on, but stops when the switch is released to the run position, it can indicate that a resistor is bad and should be replaced. At no time should the resistor be bypassed out of the circuit, as that would supply constant battery voltage and burn out the coil. The resistor and resistor wires should always be checked when the breaker points are burned, or when the ignition coil is bad.
Torsion Bars
Torsion bar suspension uses the flexibility of a steel bar or tube, twisting lengthwise to provide spring action. Instead of the flexing action of a leaf spring, or the compressing-and-extending action of a coil spring, the torsion bar twists to exert resistance against up-and-down movement. Two rods of spring steel are used in this type of suspension. One end of the bar is fixed solidly to a part of the frame behind the wheel; the other is attached to the lower control arm. As the arm rises and falls with wheel movement, the bar twists and absorbs more of the road shocks before they can reach the body of the car. The bar untwists when the pressure is released, just like a spring rebounding after being compressed. Adjusting the torsion bars controls the height of the front end of the vehicle. The adjusting bolts are located at the torsion bar anchors in the front crossmember. The inner ends of the lower control arms are bolted to the crossmember and pivot through a bushing.
Torque Converter
The torque converter is a type of fluid coupling between the engine and the gearbox to even out speed changes. The torque converter also multiplies engine torque. The torque converter is used as a clutch to send the power (torque) from the engine to the transmission input shaft. It has three parts; an impeller connected to the engine's crankshaft, a turbine to turn the turbine shaft which is connected to the gears, and a stator between the two. The torque converter is filled with transmission fluid that is moved by the impeller blades. The stator's vanes catch the oil thrown off from the impeller, and use it to move the turbine's blades. When the impeller spins above a certain speed, the turbine spins, driven by the impeller. In some designs, the torque converter locks the impeller and the turbine together when at highway speeds, which increases efficiency.
Topic Explanation
Auto Insight contains more information in greater detail then any other auto program on the market. Auto Insight is the program of choice for people who know cars (Motor Week, Motor Trend, Popular Hot Rodding, Popular Mechanics, etc). Over 1900 parts of the car are identified and explained. The product ships with BOTH Windows and DOS versions included. This section of the program covers special interest topics. The topics covered in Auto Insight are listed as they appear in the product, but only the below section are fully enabled in this demo version: The Environment (Topic Section) Cooling System Cooling System Diagram Radiator Engine System V8 Engine Spark Plugs Valve Train Carburetor and Intake Manifold AC/Heat System Anti-Lock Brakes Positraction Differential
Toe-in and Toe-Out Tread Wear
Important in the ease of steering the car is the correct setting of toe-in. Toe-in is a term used to specify the amount (in fractions of an inch) that the front wheels are closer together in front that at the rear, when measured at hub height. Precision testing equipment and careful measurement and correction will prevent any slipping or scuffing action between the tires and the road. If toe-in is incorrect, the tires will be dragged along the road, scuffing and featheredging the treadribs. Changes in road or load conditions will affect more than one steering angle, and uneven tread wear patterns will result. Changes in road or load conditions will affect more than one steering angle, and uneven tread wear patterns will result. Also, toe-in will change when other angular adjustments are made. Because of this, front wheel toe-in should be measured first and uneven tread wear patterns corrected last on all wheel alignment jobs. Toe-out Tread Wear It is obvious that driving conditions make it impossible to keep the front wheels parallel at all times. Regardless of how accurately the front wheels are positioned for straight ahead driving, they could be out of their correct relative positions on turns. Considering that the outside wheel is approximately five feet farther away from the point about which the car is turning, it must turn at a lesser angle and travel in a greater circle than the inside wheel. This condition is called toe-out turns, which means that each front wheel requires a separate turning radius to keep the inside tire from slipping and scuffing on turns. Toe-out turns is the relationship between the front wheels which allows them to turn about a common center. To accomplish this, the steering arms are designed to angle several degrees inside of the parallel position. The exact amount depends on the tread and wheelbase of the car and on the arrangement of the steering control linkage. Unless toe-out is aligned correctly, the tires will have a scrubbing action on the road surface. This will produce a featheredge on the outer edges of the tread ribs.
Tires on Racing Cars
Car tires are more than just cushions for the wheels. They also give the car a good grip on slippery roads and keep it from sliding about when braking and cornering. The tread patterns running all around the tire have thin cuts in the rubber to sponge up surface water, and zigzag channels to pump the water out behind as the car rolls forward. On a wet road, a tire has to move more than one gallon (5 liters) of water a second to give needed grip. On perfectly dry roads, the treads are not needed. A smooth tire gives the greatest possible area of contact with the road, but if smooth tires are used on wet roads, the film of water builds up in front of the tires and underneath them and actually lifts them off the road surface, a condition known as "hydroplaning." In this situation, the driver will lose control of the car. Most cars have to function in all types of weather, so their tires must have tread, but racing cars make very few outings a year. If the track is dry, they run on smooth tires, called "slicks," to get the best grip on the roads. The extra wide tires and wheels give more grip than the average car, but in wet weather, the racer must change to treaded tires.
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