Question 1

Combustion chamber

Accepted Answer

The area within the engine where the combustion of fuel and air takes place.

Question 2

Compression ratio

Accepted Answer

The ratio of the volume in the cylinder when the piston is at the bottom of its stroke to the volume when the piston is at the top of its stroke.

Question 3

Cylinder liner

Accepted Answer

A cylindrical sleeve that fits into the cylinder block, providing a smooth surface for the piston to move.

Question 4

Exhaust gas recirculation (EGR)

Accepted Answer

A system that recirculates a portion of exhaust gases back into the engine intake to reduce emissions.

Question 5

Fuel injection pump

Accepted Answer

A device that delivers fuel at high pressure to the fuel injectors.

Question 6

Glow plug

Accepted Answer

A heating element used to heat the air inside the combustion chamber for easier cold starts.

Question 7

Injection timing

Accepted Answer

The precise moment when fuel is injected into the combustion chamber.

Question 8

Intercooler

Accepted Answer

A device that cools the compressed air before it enters the engine to increase air density and improve performance.

Question 9

Manifold pressure sensor

Accepted Answer

A sensor that measures the pressure of the intake manifold.

Question 10

Nitrogen oxide (NOx)

Accepted Answer

A pollutant produced during combustion, which contributes to smog and acid rain.

Question 11

Oil cooler

Accepted Answer

A device that cools the engine oil to prevent overheating.

Question 12

Piston rings

Accepted Answer

Rings fitted around the piston to provide a seal and prevent the escape of combustion gases.

Question 13

Positive crankcase ventilation (PCV)

Accepted Answer

A system that recirculates blow-by gases from the crankcase back into the intake manifold.

Question 14

Power stroke

Accepted Answer

The phase of the four-stroke engine cycle where combustion of fuel and air produces power.

Question 15

Precombustion chamber

Accepted Answer

A small chamber within the main combustion chamber where fuel is introduced for more efficient combustion.

Question 16

Retarder

Accepted Answer

A device used to slow down a vehicle by absorbing and dissipating kinetic energy.

Question 17

Scavenging

Accepted Answer

The process of purging the exhaust gases from the combustion chamber during the exhaust stroke.

Question 18

Thermostat

Accepted Answer

A temperature-sensitive valve that regulates the flow of coolant through the engine.

Question 19

Torque converter

Accepted Answer

A fluid coupling that transmits power from the engine to the transmission.

Question 20

Turbocharger

Accepted Answer

A device that increases the density of air entering the engine by compressing it with a turbine driven by exhaust gases.

Question 21

Valve overlap

Accepted Answer

The period of time when both the intake and exhaust valves are partially open during the engine cycle.

Question 22

Variable geometry turbocharger (VGT)

Accepted Answer

A turbocharger with adjustable vanes that optimize boost pressure based on engine speed and load.

Question 23

Water separator

Accepted Answer

A device used to remove water and contaminants from the fuel before it reaches the engine.

Question 24

Air-to-air charge cooler

Accepted Answer

An intercooler that cools the compressed air using ambient air before it enters the engine.

Question 25

Camshaft

Accepted Answer

A rotating shaft with eccentric lobes that actuate the opening and closing of the engine's valves.

Question 26

Cold start advance

Accepted Answer

The additional fuel injection timing advance used during cold starts to aid combustion.

Question 27

Crankcase breather

Accepted Answer

A device that allows gases to escape from the crankcase while preventing the entry of debris.

Question 28

Cylinder head

Accepted Answer

The top part of the engine block that contains the combustion chambers and valve train.

Question 29

Diesel oxidation catalyst (DOC)

Accepted Answer

A device that reduces harmful emissions by promoting the oxidation of pollutants.

Question 30

Engine brake

Accepted Answer

A device that uses engine compression to slow down a vehicle, often used in heavy-duty applications.

Question 31

Fuel rack

Accepted Answer

A mechanical device that controls the amount of fuel injected into the cylinders.

Question 32

Glow plug control module

Accepted Answer

An electronic module that controls the operation of the glow plugs.

Question 33

Injection pump timing

Accepted Answer

The timing at which the fuel injection pump delivers fuel to the injectors for combustion.

Question 34

Injector sleeve

Accepted Answer

A protective sleeve that surrounds the fuel injector and seals it within the cylinder head.

Question 35

Intake manifold

Accepted Answer

A system of passages that distribute air or air-fuel mixture to the engine cylinders.

Question 36

Knock sensor

Accepted Answer

A sensor that detects engine knock or detonation and adjusts engine timing accordingly.

Question 37

Oil pressure regulator

Accepted Answer

A device that regulates the oil pressure within the engine to ensure proper lubrication.

Question 38

Piston cooling jets

Accepted Answer

Small passages that direct oil to spray onto the underside of the piston, helping to dissipate heat.

Question 39

Positive displacement pump

Accepted Answer

A pump that delivers a fixed volume of fluid per revolution, such as a fuel or oil pump.

Question 40

Primary fuel filter

Accepted Answer

A filter located between the fuel tank and the fuel injection pump, removing contaminants from the fuel.

Question 41

Secondary air injection (SAI)

Accepted Answer

A system that introduces fresh air into the exhaust stream to facilitate the oxidation of pollutants.

Question 42

Supercharger

Accepted Answer

A device that forces additional air into the engine, increasing power output.

Question 43

Throttle position sensor (TPS)

Accepted Answer

A sensor that measures the position of the throttle plate to determine engine load.

Question 44

Timing belt

Accepted Answer

A belt that connects the crankshaft and camshaft(s), ensuring synchronization of their rotation.

Question 45

Turbo-compound engine

Accepted Answer

An engine that recovers waste energy from the exhaust gases using a turbine to drive the crankshaft.

Question 46

Variable valve timing (VVT)

Accepted Answer

A system that adjusts the timing of the intake and/or exhaust valves for optimal engine performance.

Question 47

Water pump

Accepted Answer

A pump that circulates coolant throughout the engine to maintain proper operating temperature.

Question 48

Camshaft position sensor (CMP)

Accepted Answer

A sensor that detects the position of the camshaft(s) to synchronize fuel injection and ignition timing.

Question 49

Compression brake

Accepted Answer

A device that utilizes engine compression to provide braking force, commonly known as a "Jake brake."

Question 50

Diesel particulate filter (DPF)

Accepted Answer

A device that captures and traps particulate matter from diesel exhaust, reducing emissions.

Question 51

Engine control module (ECM)

Accepted Answer

The main electronic control unit that manages engine operation and performance.

Question 52

Variable geometry intake (VGI)

Accepted Answer

An intake system that adjusts the length and/or diameter of the intake manifold for improved airflow and torque at different engine speeds.

ASE Medium-Heavy Truck Certification: T2 Diesel Engines Flashcards