Auto and Shop Information ASVAB Terms

1. What type of engine is used in automobiles?

Internal Combustion Engine.

Explanation: An internal combustion engine works by combining a high-energy fuel (such as gasoline) with an oxidizing agent (such as air). The mixture produces a hot, high-pressure gas that helps propel movement in the engine. 

2. In an internal combustion engine, the four-stroke cycle begins with which stroke?

The intake stroke.

Explanation: During the intake stroke, the piston moves from top to bottom, and the intake valve is open. The movement of the piston from top to bottom causes a low pressure vacuum, which in turn causes the air-fuel mixture through the open intake valve and into the cylinder.

3. What is the function of the water pump?

The water pump controls heat by moving coolant through the cooling system.

Explanation: It is in charge of transferring and controlling heat by circulating coolant via the cooling system.

4. What is engine coolant composed of?

50% water and 50% ethylene glycol.

Explanation: Ethylene glycol is more commonly referred to as antifreeze.

5. What is the name of the mechanism that controls the output from the alternator?

Voltage regulator.

Explanation: The voltage regulator senses increased load when electrical systems such as the headlights are turned on, and it responds by increasing the alternator’s output to meet demand.

6. What are the four components of the braking system?

Brake pedal, master cylinder, fluid reservoir, and brake lines. Explanation: The brake pedal is the connection between the driver’s foot and the master cylinder. The master cylinder is a hydraulic pump that forces fluid into the wheel cylinders when the brake pedal is touched, creating a friction that helps the vehicle slow or stop. The fluid reservoir holds the break fluid and sits on top of the master cylinder. The break lines transmit fluid from the master cylinder to the brake assemblies.

7. What is the difference between disc brakes and drum brakes?

Drum brakes feature a round drum that houses all of the working components. When the brake pedal is pushed, fluid causes two shoes inside to push against the brake drum and slow the wheel. Disc brakes feature a rotor and a caliper that houses two brake pads. When the brake pedal is activated, the brake pads clamp together on either side of the rotor. Explanation: Many manufacturers switched to disc brakes in the early 1970s because of their power and superior ability to manage heat.

8. What is the function of a catalytic converter?

The catalytic converter takes three harmful by-products of car exhaust―carbon monoxide, nitrogen oxides, and hydrocarbons―and uses a catalyst to convert them into harmless compounds.

Explanation: To comply with EPA regulations, all gasoline cars since 1975 have been equipped with catalytic converters.

9. What engine component connects the crankshaft and piston?

Connecting rod

Explanation:

The smaller end of the connecting rod connects to the piston via a wrist (piston) pin, while the larger end connects to the crankpin journal.

10. What is the name of the important property of oil that can be defined as “a resistance to flow”?

Viscosity

Explanation: The Society of Automotive Engineers (SAE) develops the standards for oil viscosity, which is expressed as a number that corresponds to the thickness of the oil. For example, SAE 10 oil has a lower viscosity (which means that it is thinner) than oil that is rated SAE 40.

11. An American Petroleum Institute (API) engine oil rating that contains the prefix “C” signifies what?

The oil should be used in diesel engines.

Explanation: An “S” rating signifies use in gasoline engines.

12. What tool would you select if you needed to measure to the thousandth of an inch?

A micrometer.

Explanation: Also called a micrometer screw gage, a micrometer typically is in the form of a caliper.

13. What tool would you select to measure an angle?

A steel square.

Explanation: A steel square is a tool that is composed of a wider arm, called the blade, and a narrower arm, called the tongue. Because steel squares are often used by carpenters, they are also called carpenter’s squares or framing squares.

14. What hammer type would be best suited for ripping up and repairing old decking?

A claw hammer.

Explanation: Claw hammers have two ends: one to drive nails in and one to help remove them. Claw hammers are well-suited for projects involving construction.

15. Which two tools would be appropriate choices for loosening fasteners?

Wrenches and sockets.

Explanation: There are several types of wrenches and sockets, each best suited for a different job. With wrenches, the longer the wrench, the more torque available to loosen a fastener.

16. What is the function of wrist pins in an internal combustion engine?

Wrist pins connect the piston to the connecting rod.

Explanation: In a car’s engine, there are many parts that work together to make the car move. One important part is called a ‘wrist pin.’ Think of it like a small metal pin that helps connect two other parts: the piston and the connecting rod. The piston moves up and down inside part of the engine called a cylinder, and this movement helps turn fuel into power that makes your car go. The connecting rod connects to both the piston and another part called the crankshaft, helping change up-and-down motion into round-and-round motion. Without wrist pins, this important connection couldn’t happen, making them really essential for your car’s engine to work properly.

17. What is the function of the radiator in a car’s cooling system?

The radiator cools the coolant by transferring heat from the coolant to the air.

Explanation: In a car, the engine gets very hot when it runs. To keep it from getting too hot, cars have a cooling system. Part of this system is called the radiator. The radiator has coolant fluid inside it that absorbs heat from the engine and then moves to the radiator. When air passes over or through the radiator (like when you’re driving), it cools down this fluid by taking away some of its heat. This cooled fluid goes back into the engine to pick up more heat and keep it at a safe temperature. Think of it like how sweating helps cool you down on a hot day; as your sweat evaporates, it takes some of your body’s heat with it.

18. What is the function of the thermostat in a car’s cooling system?

The thermostat regulates the temperature of the coolant by opening and closing the flow of coolant to the radiator.

Explanation: A car’s cooling system stops the engine from overheating. Picture the thermostat as a gate that controls when the coolant, a special liquid that picks up heat from the engine, can move. When your car’s engine begins to heat up too much, the thermostat “opens” to allow the coolant to flow to the radiator. The radiator cools this liquid down, and then it returns to the engine to pick up more heat. This process keeps the engine’s temperature just right, so your car runs well.

19. What is the purpose of oil galleries or passages in an engine?

Oil galleries or passages are channels in the engine block that direct oil to various engine components for lubrication.

Explanation: An engine needs oil so all its parts can move easily without rubbing against each other too much. Rubbing, or friction, can make the parts wear out fast and make the engine overheat. To prevent this, engines have a system that sends oil all over the inside. This system has oil galleries or passages, which are like tiny rivers inside the engine. The oil flows through these “rivers” to get to all the parts of the engine that need oil, especially where there’s a lot of metal moving against metal, like where the pistons go up and down.

20. What is the purpose of a catalytic converter in a vehicle’s exhaust system?

A catalytic converter reduces harmful emissions from the engine. Explanation: A catalytic converter is a device used in the exhaust system of a vehicle to reduce the pollution that comes out of the engine. It does this by converting harmful gases produced during combustion, such as carbon monoxide, nitrogen oxides, and hydrocarbons, into less harmful substances like carbon dioxide and water vapor. This conversion happens through a chemical reaction facilitated by a catalyst, which is a substance that speeds up a chemical reaction without being consumed by it. The catalytic converter plays a crucial role in reducing the environmental impact of a vehicle by significantly lowering the amount of harmful emissions released into the atmosphere.