14. Auto Information

Question 1

What is a vehicle chassis?

Answer 1

A vehicle’s chassis keeps all its systems and components together. It accommodates the frame, gearbox, engine, axles, and every other system. Think of the chassis as a vehicle’s skeleton, because without it, the vehicle is just a heap of parts sitting on the ground.

Question 2

What is the frame of a chassis?

Answer 2

The frame is the main structure of the chassis, like the backbone. the frame supports the vehicle’s body and all its mechanical components as well as the weight of passengers and cargo inside. It has a lot of other jobs, too: It deals with the torsional and vertical twisting caused by driving over uneven surfaces, torque from the engine and transmission, and tensile forces from starting, acceleration, and stopping.

Question 3

What is the difference between unibody construction and body-on-frame construction?

Answer 3

Most modern cars and trucks feature unibody construction, which means the chassis (including the frame) and body are integrated into one piece. On the other hand, older cars and most modern trucks feature body-on-frame construction, using two separate components for body and frame.

Question 4

Explain the four-stroke cycle.

Answer 4

1. Intake stroke: The intake valve opens as the connecting rod pulls the piston down from its TDC position, creating a vacuum that sucks the air-fuel mix into the cylinder. the piston goes to the BDC position. the intake valve closes, sealing the air-fuel mixture inside the combustion chamber portion of the cylinder.
2. Compression stroke: The connecting rod pushes the piston up, compressing the air-fuel mixture inside the combustion chamber. This compression builds up energy because it excites the molecules and generate heat. the flywheel helps compress the charge (the volume of compressed air-fuel mixture trapped inside the combustion chamber). The mixture ignites through chemical reaction — combustion — when the piston is almost back at TDC and a spark plug releases a spark. The spark heats the gases in the combustion chamber even more, which causes an explosion of energy.
3. Combustion stroke: The explosion forces the piston down. Because the intake and exhaust valves are still closed, the explosion pushes down on the connecting rod, turning the crankshaft; the crankshaft turns the flywheel, which keeps the engine going.
4. Exhaust stroke: The exhaust valve opens as the connecting rod moves the piston back up, pushing out the leftover gases from the explosion. At this point, their energy is spent. The valves are timed, of course, using push rods attached to camshaft. Complete expulsion of the exhaust prepares the engine to repeat the intake stroke.

Question 5

What is TDC and BDC? Differentiate.

Answer 5

The piston has two distinct positions: top dead center, or TDC, and bottom dead center, or BDC.

Question 6

What are the 11 common components of internal combustion engines?

Answer 6

1. Pistons: A piston is a cylindrical object with a solid crown at the top. One piston moves up and down in each cylinder.
2. Piston rings: Piston rings seal the piston to the cylinder. They prevent gases from leaking out. Similarly, oil rings stop engine oil from getting into the combustion chamber.
3. Cylinders: A cylinder houses a piston and other components. It’s where the piston and the air-fuel mixture work together to transfer energy.
4. Cylinder head: A cylinder head is the part of the cylinder located above the piston. It’s where you find the combustion chamber as well as the intake and exhaust valves and ports.
5. Combustion chamber: A combustion chamber is inside the cylinder head, right above the piston. the air-fuel mixture combusts inside the chamber.
6. Intake valves: An intake valve lets the air-fuel mix enter the combustion chamber after the combustion.
7. Exhaust valves: The exhaust valves let waste gases exit the combustion chamber after combustion.
8. Crankshaft: The crankshaft turns a piston’s up-and-down motion into a rotary motion (like a crank).
9. Camshaft: A camshaft is what opens and closes the intake and exhaust valves. It turns at half the speed of the crankshaft.
10. Wrist pins: A wrist pin connects the piston to the connecting rod.
11. Connecting rods: A connecting rod connects each piston and wrist pin assembly to the crankshaft.

Question 7

Name the blanks within this figure of a four-stroke engine.

Answer 7

Question 8

What is a tachometer?

Answer 8

An instrument measuring revolution per minute [rpm] on your dashboard).

Question 9

What is the difference between carburetors and fuel injectors?

Answer 9

1. Carburetors: Carburetors are used on most older cars (those made before the early 1990s) to mix the fuel and air mechanically. As air moves quickly through the carburetor, it creates a vacuum, which draws more and more fuel into the mixture. While no major car manufacturers currently use carburetors, some manufacturers build motorcycles with them.
2. Fuel injectors: Fuel injectors replaced carburetors on newer cars to perform the air-fuel mixture function. (Fuel injectors have been around since the late 1950s.) The fuel injector acts as the fuel-dispensing nozzle. It injects liquid fuel directly into the engine’s air stream. In almost all cases, this requires an external pump.

^{All mass-produced cars today use an electronic fuel injection system, or EFI, which receives commands from the powertrain control module PCM computer. The PCM receives information from the sensors in the fuel, air, and exhaust system, and from that information it determines how much fuel the engine needs to operate at optimum levels.}

Question 10

What is the throttle and the accelerator? Synthesize it.

Answer 10

A throttle is mechanically connected to the carburetor or electronically connected to the EFI computer. Advancing (opening) the throttle causes more fuel to be transferred to the carburetor or the fuel injectors. The accelerator (gas pedal) is connected to the throttle by electrical connections and — in older vehicles — mechanical linkages. The harder you push on the gas pedal, the farther the throttle is advanced (opened). Thus, more fuel is transported to the carburetor or fuel injectors.

Question 11

What is the difference between a car with fewer cylinders and a car with more cylinders?

Answer 11

Engines with more cylinders can combust more fuel, which creates more movement to turn the crankshaft — and more power to move the vehicle. Engine with fewer cylinders tend to be more efficient, but they’re usually less powerful than engines with more cylinders are. Generally, you have to trade power for efficiency when you buy a vehicle with an internal combustion engine.

Question 12

What are the three types of common cylinder arrangements?

Answer 12

1. In-Line
2. V-Type
3. Horizontally Opposed

Question 13

WHat is a diesel engine?

Answer 13

Diesel engines, also called compression ignition engines, are internal combustion engines, but they’re little simpler than standard gasoline engines. Many of the vehicles you’ll use in the military are diesel-powered. Diesel engines don’t rely in a spark to ignite the fuel. Instead, the engine injects fuel right into the combustion chamber of a cylinder, where the air is so compressed (and hot) that it ignites without a spark. Glow plugs assist in heating the air, but they don’t produce an electrical spark.

Question 14

Explain the octane ratings.

Answer 14

Octane ratings measure gasoline’s ability to resist engine knock, a rattling or pinging sound that results from premature ignition of the compressed air-fuel mixture in one or more cylinders. Most gas stations offer three octane grades: regular (usually 87 octane), midgrade (usually 89 octane), and premium (usually 91, 92, or 93). By federal law, the ratings must be posted on bright yellow stickers on each gasoline pump.

The octane rating correlates to how much the gasoline can be compressed before it ignites spontaneously. When gasoline ignites this way, instead of by the spark of a spark plug, the engine begins knocking. That’s not a good thing because early ignition can cause engine damage over time.

But don’t be fooled — that doesn’t mean using higher octane gas is better. In most cases, using higher octane gasoline than your owner’s manual recommends offers absolutely no benefit. It won’t make your car perform better, go faster, get better mileage, or run cleaner. The only time you may need to switch to a higher-octane level is if your car engine knocks when you use the recommended fuel. This happens to a small percentage of cars. buying higher octane gasoline can be a waste of money, too. Premium gas can cost at least 30 to 40 cents per gallon more than regular gas does. That can add up to hundreds of dollars a year in unnecessary spending.

Question 15

How can you tell if you’re using the right octane level?

Answer 15

Read your owner’s manual and listen to your car’s engine. If it does not knock when you use the recommended octane, you’re probably using the right grade of gasoline.

Question 16

Describe EVs.

Answer 16

EVs aka. electric vehicles are a lot like their gasoline — and diesel-powered counterparts, but they have one or more electric motors that take power from a large (and very heavy) battery. Some electric vehicles have a smaller electric motor at each wheel, which eliminates the need for a transmission, drive shaft, and axles, ultimately, making them simpler than other types of engines. On-board computers control the amount of electricity sent to each motor for precise performance. Because they use electric motors, EVs have instant torque at their wheels and can reach high speeds very quickly.

Question 17

Describe hybrid vehicles.

Answer 17

Hybrid vehicles use widely available gasoline or diesel fuel to help power electric motors. A small gasoline or diesel engine powers the vehicle and a generator; the generator provides electricity to the vehicle’s electric motors. Sometimes the vehicle stores energy in a small batter bank, which allows it to run purely as an electric vehicle for a short time. Hybrids were originally designed for efficiency, and they’re becoming increasingly popular — you’ll even find them in some military applications.

Question 18

The battery powers an electrical motor that starts the engine when you turn the key or push the ignition button. What is the name of this electrical motor that starts the engine?

Answer 18

This motor is called a starter.

Question 19

What is an alternator?

Answer 19

An alternator sends an electric current back to the battery, keeping it charged, and powers the electronics on your car when the engine is running.

Question 20

What is the ignition system?

Answer 20

The ignition system supplies a high-voltage current to the spark plugs to ignite the fuel mixture in the cylinders. The system takes the 12-volt current from the battery, steps it up to about 20,000 volts, and then sends the current to the spark plugs.

Question 21

Synthesize the concept of coil, distributor, breaker points and condenser.

Answer 21

In older cars, and diesel engines, this increase of voltage is accomplished by means of a device called a coil, which uses electromagnetic induction to step up the voltage. The current then passes through an electrical/mechanical switching device called a distributor. A rotating shaft and a switch within the distributor, called breaker points, route the current through wires to the spark plugs. A condenser absorbs excess current and protects the breaker points from damage by the high-voltage surge. The distributor and other devices control the timing of the spark-plug discharges.

Question 22

In your car, without a cooling system…

Answer 22

the engine would melt, and you’d have to use your LPCs to get around (that’s your leather personnel carriers, or combat boots.

Question 23

Most modern internal combustion engines are liquid-cooled. How does this kind of cooling system work?

Answer 23

A water pump pushes liquid coolant through water jackets, which surround the parts of the engine that reach the highest temperatures. The coolant picks up heat and carries it through the engine’s radiator, where the heat disperses when the coolant is exposed to outside air.

Question 24

Why does the water in a liquid cooled cooling system does not boil?

Answer 24

the water in the system is mixed with coolant (antifreeze), which raises the boiling point of water (which keeps the water from boiling away) and lowers its freezing point (which keeps the system from freezing up during cold weather).

Question 25

A standard lubrication system includes the following: Synthesize.

Answer 25

1. Oil pump: The oil pump pushes the motor oil through the engine. Usually, the camshaft controls the oil pump.
2. Oil galleries: Oil galleries are pathways that oil takes through the engine.
3. Oil pan: The oil pan is the reservoir where all the oil pools. It’s at the bottom of the engine.
4. Pickup tube and screen: The pickup tube sends oil into the pump, and the screen filters out solid materials that could clog up the system.
5. Oil filter: The oil filter cleans out the contaminants before the oil gets circulated back through the engine.

Question 26

What does the exhaust system do?

Answer 26

The byproducts of combustion and other engine functions have to go somewhere, and they have to be able to escape the engine freely. The exhaust system manages all of an engine’s byproducts.

Question 27

The exhaust system manages all of an engine’s byproducts by using what components? Define each.

Answer 27

• Exhaust manifold: The manifold connects to the exhaust ports on the cylinder head, where combustion takes place.
• Catalytic converter: The catalytic converter contains a honeycomb-like set of passageways or small ceramic beads coated with catalysts that create chemical reactions. These chemical reactions transform the most toxic compounds in exhaust to less-harmful compounds, like carbon dioxide and water.
• Muffler: The muffler provides a place for gases to expand (quietly) because it’s made from sound-absorbing material.
• Tailpipe: The tailpipe is the exit door for exhaust.

Question 28

What does the emission-control system do?

Answer 28

Exhaust systems are not the only systems that deal with emissions. Think of the engine as a giant cigarette and the emissions-control system as a filter. The exhaust from automobiles contains pollutants, including carbon monoxide. These pollutants are a result of the combustion process (or they’re partially combusted or unburned fuel). To prevent these pollutants from poisoning the atmosphere, manufacturers place emission-control system on cars.

Question 29

What does the emissions-control system include to prevent these pollutants from poisoning the atmosphere?

Answer 29

• Positive-crankcase ventilation: An old method (still in use) that forces unspent or partially spent fuel back into the cylinder so the fuel can burn.
• Air-injection system: System that forces air into the engine’s exhaust system to reuse unburned or partially burned fuel before the fuel comes out the exhaust pipe.
• Catalytic converter: Oxidizes hydrocarbons and carbon monoxide into water vapor and carbon dioxide (the same thing people exhale); doesn’t control other types of pollutants such as nitrogen oxides.
• Exhaust-gas-recirculation system: Helps control nitrogen-oxide emissions by forcing some of the gases back into the cylinders.

Question 30

What is the job of the drive system?

Answer 30

Having a working engine is all fine and dandy, but the power of the engine still has to be transferred to the wheels to make them move. This is the job of the drive system.

Question 31

Synthesize the concept of drivetrain systems, axles, universal joint, and drive shaft.

Answer 31

Cars have drivetrain systems that run on axles. The axle is the shaft on which the wheels revolve. The universal joint allows the axle to move up and down without breaking the drive shaft. The drive shaft is the connecting component that carries torque and transmits rotation.

Question 32

Axle shafts turn the wheels. The wheels on vehicle turn in three different ways, what are those 3? Differentiate.

Answer 32

1. Rear-wheel drive: The rear wheels push the car. The drive shaft extends from the transmission to the rear axle.
2. Front-wheel drive: The front wheels pull the car. The drive shaft extends from the transmission to the front axle.
3. All-wheel drive (four-wheel drive): All wheels push and pull the car at the same time. The drive shaft extends from the transmission to both axles.

Question 33

Four-wheel vehicles typically have locking differentials, these differentials are…

Answer 33

The handy mechanical components that allow powered wheels to turn at different speeds.

Question 34

The drive system also includes transmission, what is this kind of transmission do?

Answer 34

The transmission changes the speed of the engine in relation to the speed of the rear wheels (in rear-wheel drive) the front wheels (in front-wheel drive), or all the wheels (in four -wheel or all-wheel drive). Vehicles have two types of transmissions: automatic or manual (stick shift).

Question 35

The drive systems’ transmission consists of several gears that allow the driver to control the amount of torque used. What are those? differentiate.

Answer 35

The transmission consists of several gears that allow the driver to control the amount of torque used. When the terrain is difficult (for example, steep) the wheels need more torque (the force that produces rotation) in order to move. You need less torque when you’re driving on slippery surfaces to help prevent your wheels from spinning. the transmission increases torque as needed. In an automatic transmission, the torque change is automatic thanks to a torque converter. In a manual transmission, the driver shifts the gears by compressing the clutch, which disconnects the engine from the drive shafts, and moving the gear shift inside the car by hand. Changing to a different gear (torque) requires temporarily disconnecting the engine. The clutch also allows the engine to run when the car isn’t moving.

Question 36

What the suspension and steering systems’ job?

Answer 36

The suspension system, steering system, and tires, with some help from on-board computers, lets you control the vehicle.

Question 37

What does the suspension system do?

Answer 37

The suspension system maximizes friction between the tires and the road surface by keeping the two in contact as much as possible, which gives a driver the ability to handle the car well.

Question 38

What are the most important parts of a suspension system?

Answer 38

• Struts: Struts supports the weight of the vehicle and keep it from collapsing to the ground. Typically, a strut has an attached spring that helps the vehicle adapt to irregularities in the road.
• Shock absorbers: Also simply called shocks, these handy gadgets are part of the struts in modern cars. They consist of a piston inside a hydraulic fluid-filled, sealed tube. When the tire hits a bump (or anything else), it pushes up the piston inside the tube instead of jolting the vehicle’s chassis.
• Tires: The tires are a vehicle’s first — and hopefully only — contact with the road. The air inside the tires helps with stability and handling. The rubber creates traction caused by friction.
• Springs: Springs hold the chassis up and work with the shocks to let the wheels move up and down smoothly.
• Steering knuckle: The steering knuckle is the connection point between a tie rod and a wheel, and it’s the point that controls where the wheel turns.
• Control arms: Also called A-arms, these long, metal pieces connect to the steering knuckle with ball joints and keep it vertical when the wheels move up and down. You find and upper and a lower arm on each steering knuckle.
• Tie rods: Tie rods transfer force from the steering linkage or steering rack to the steering knuckle, which causes a wheel to turn.

Question 39

What are the two steering systems most car use?

Answer 39

Rack-and-pinion or Pitman arm steering. Both of these types of steering are often power assisted, which makes turning the steering wheel and getting a response from the vehicle’s wheels easier.

Question 40

Why shouldn’t you use the brake very too much?

Answer 40

Each wheel has a break that applies friction to the wheel to stop its rotation. The friction takes motion energy and turns it into heat energy (which is why you shouldn’t ride your brakes — they’ll overheat and degrade).

Question 41

All types of brake system share several components. What are those? Synthesize.

Answer 41

First, the brake pedal provides the connection between the driver and the braking mechanism. That master cylinder is just on the other side of the brake pedal, and its job is to push brake fluid through brake lines that operate the brake assemblies at the wheels. (That fluid comes from — and goes back to — the fluid reservoir, which sits on top of the master cylinder). What happens next depends on the types of brakes.

Question 42

What are the two common types of brakes?

Answer 42

1. Drum brakes: In a drum brake, the lines are connected to a hydraulic cylinder on each wheel. This cylinder contains pistons that move outward and force two brake shoes against the metal drum that rotates with the wheel.
2. Disc brakes: In a disc-brake system, the master cylinder forces a caliper containing a piston or pistons, with brake pads on each side, to squeeze against a rotor disc in each wheel, thus, stopping your car by using fluid and pressure on both sides of the rotor.

Question 43

Describe the magic of ABS?

Answer 43

In the modern world of cars, most vehicles are equipped with an antilock brake system (ABS). The ABS is a four–wheel system (usually) that prevents the wheels from locking up. The system does this by automatically adjusting the brake pressure during an emergency stop. This enables the driver to maintain steering control and to stop in the shortest possible distance under most conditions.

The theory behind ABS is simple. If your car isn’t equipped with ABS and you have to stop quickly, your wheels simply stop turning when you hit the brakes. If your tires don’t have much traction on the road, your car may continue forward in a skid even though the wheels are locked. You don’t stop as quickly as you would with ABS, and you won’t be able to steer. However, with ABS, your wheels are slowed to a stop as quickly as possible, without locking up, which give you much better control during an emergency stop situation.