Question 1

Two technicians are discussing the starting system. Technician A says that the ignition switch is part of the starting system. Technician B says that antitheft circuits are not part of the starting system. Who is correct?
A)A only
B)B only
C)Both A and B
D)Neither A nor B

Accepted Answer

Technician A is correct. The ignition switch is part of the starting system as it controls the flow of electricity to the starter when the key is turned. Technician B is incorrect as antitheft circuits can be integrated into the starting system to prevent unauthorized starting of the vehicle.

Question 2

A rotary engine uses a rotor to compress the air/fuel mixture.

Accepted Answer

A rotary engine does not have traditional pistons like a piston engine, but rather uses a rotor to compress the air/fuel mixture.

Question 3

Today's engine design is very different from the original basic engine design from the 1890's.

Accepted Answer

Over the years, engine design has gone through significant changes and innovations, incorporating advanced technologies such as fuel injection, electronic controls, variable valve timing, turbocharging, and hybrid powertrains.

Question 4

Two technicians are discussing automotive power systems. Technician A says that today's engines operate on different principles than those of the past. Technician B says that today's engine has more computerized sensors and actuators than did an entire vehicle had in the mid-1980's. Who is correct?
A)A only
B)B only
C)Both A and B
D)Neither A nor B

Accepted Answer

The answer of Two technicians are discussing automotive power systems....

Question 5

Two technicians are discussing engine sensors. Technician A says that MAP sensors measure altitude. Technician B says MAF sensors measure exhaust flow. Who is correct?
A)A only
B)B only
C)Both A and B
D)Neither A nor B

Accepted Answer

Both technicians are incorrect. MAP (Manifold Absolute Pressure) sensors measure the pressure inside the intake manifold, which is used to calculate the engine load. MAF (Mass Air Flow) sensors measure the amount of air entering the engine, which is used to calculate the fuel needed for combustion.

Question 6

The powertrain has become the most complex system in the vehicle.

Accepted Answer

Over the years, the powertrain has incorporated a variety of complex components such as engines, transmissions, batteries, electric motors, and more, making it the most intricate system in the vehicle.

Question 7

A four-stroke engine produces a power stroke for every two revolutions of the crankshaft.

Accepted Answer

A four-stroke engine requires four strokes (intake, compression, power, exhaust) to complete one cycle, which corresponds to two revolutions of the crankshaft. Therefore, there is one power stroke for every two revolutions.

Question 8

Two technicians are discussing PCV systems. Technician A says that PCV systems are connected to a port on the intake manifold. Technician B says that PCV systems prevent the fuel tank from over-pressurizing. Who is correct?
A)A only
B)B only
C)Both A and B
D)Neither A nor B

Accepted Answer

PCV (Positive Crankcase Ventilation) systems are indeed connected to a port on the intake manifold. This allows gases from the crankcase to be recirculated and burned with the fuel mixture in the combustion chamber. Technician B is incorrect as PCV systems have no direct relation to the fuel tank and their primary function is to prevent the buildup of pressure in the engine's crankcase.

Question 9

Actuators are _____.
A)the most common sensors on a vehicle
B)electrical devices that do the work commanded by the PCM
C)vehicle speed sensors
D)computer-controlled mechanical devices

Accepted Answer

Actuators are electrical devices that respond to signals sent by the Powertrain Control Module (PCM) to perform a specific task in the vehicle. They are responsible for converting the electrical signal from the PCM into mechanical or physical motion. Typical examples of actuators in a vehicle include fuel injectors, throttle actuators, and solenoids for controlling transmission shifts or engaging the air conditioning compressor. Actuators work in conjunction with sensors to help the PCM monitor and adjust various systems in the vehicle.

Question 10

Two technicians are discussing EFI systems. Technician A says that most modern EFI systems have one injector per cylinder. Technician B says that direct injection uses one central injector for the engine. Who is correct?
A)A only
B)B only
C)Both A and B
D)Neither A nor B

Accepted Answer

Most modern EFI systems do have one injector per cylinder. Technician B is incorrect as direct injection does not use one central injector for the engine, but instead has an injector for each cylinder or a central injector for each bank of cylinders.

Question 11

Two technicians are discussing engine operation. Technician A says that valve timing is critical to smooth engine operation. Technician B says that ignition timing is critical to smooth engine operation. Who is correct?
A)A only
B)B only
C)Both A and B
D)Neither A nor B

Accepted Answer

Both valve timing and ignition timing are critical to smooth engine operation. Valve timing ensures that the intake and exhaust valves open and close at the optimal times for efficient combustion and power production, while ignition timing ensures that the fuel-air mixture ignites at the optimal time for maximum power and efficiency. Incorrect valve timing or ignition timing can result in rough engine operation, decreased power, and increased emissions. Thus, both technicians are correct.

Question 12

Older vehicles use a(n)_____ catalytic converter.
A)one-way
B)two-way
C)three-way
D)four-way

Accepted Answer

Older vehicles typically use two-way catalytic converters, which only reduce carbon monoxide and hydrocarbon emissions. Three-way and four-way catalytic converters were developed later and can also reduce nitrogen oxides.

Question 13

Four-cylinder, in-line, gasoline engines are used less frequently in modern cars because of the block's weight and size.

Accepted Answer

Four-cylinder, in-line, gasoline engines are actually still commonly used in modern cars due to their efficiency and fuel economy. Their compact size and lightweight construction also make them appealing for car manufacturers.

Question 14

Pressurized oil is required to maintain a space between the rod bearing and the crankshaft.

Accepted Answer

The pressurized oil creates a film that separates the bearing and crankshaft, reducing friction and wear. Without this oil pressure, metal-to-metal contact can occur, leading to damage and potential engine failure.

Question 15

Two technicians are discussing exhaust systems. Technician A says that exhaust systems were originally designed to clean the exhaust gases. Technician B says that today's cleaner-running vehicles do not need emission devices. Who is correct?
A)A only
B)B only
C)Both A and B
D)Neither A nor B

Accepted Answer

Exhaust systems were originally designed to quiet the engine noise, not to clean exhaust gases. Modern vehicles still require emission devices to meet environmental standards, despite running cleaner than older models.

Question 16

Turbochargers use a belt drive to turn the rotors which compress the incoming air.

Accepted Answer

Turbochargers are not belt-driven; they are driven by exhaust gases from the engine.

Question 17

The charging system consists of the generator, battery, and starter.

Accepted Answer

The charging system consists of the generator (alternatively called the alternator), battery, and voltage regulator. The starter is part of the starting system, not the charging system.

Question 18

What is a characteristic of a rotary engine?
A)Turns in two directions with the stop-and-start motion of a piston
B)Has the same problem with harmful emissions as piston engines
C)Produces less horsepower with more wasted energy than a conventional reciprocating engine
D)Is more efficient producing more torque than a piston engine of the same displacement

Accepted Answer

The answer of What is a characteristic of a rotary...

Question 19

The PCM performs all necessary calculations based on input from the engine, transmission, and other sensor input.

Accepted Answer

The PCM (Powertrain Control Module) is designed to receive inputs from various sensors in the engine and transmission to control the operation of the vehicle. It performs calculations based on these inputs and adjusts various engine and transmission functions accordingly.

Question 20

The amount of air that an engine can move in one cycle is its displacement.

Accepted Answer

Displacement refers to the volume of air/fuel mixture that an engine can move in one cycle. It is commonly measured in cubic centimeters (cc) or liters (L).

Quiz 8: Powertrain Systems Operation

Two technicians are discussing the starting system. Technician A says that the ignition switch is part of the starting system. Technician B says that antitheft circuits are not part of the starting system. Who is correct?

A rotary engine uses a rotor to compress the air/fuel mixture.

Today's engine design is very different from the original basic engine design from the 1890's.

Two technicians are discussing automotive power systems. Technician A says that today's engines operate on different principles than those of the past. Technician B says that today's engine has more computerized sensors and actuators than did an entire vehicle had in the mid-1980's. Who is correct?

Two technicians are discussing engine sensors. Technician A says that MAP sensors measure altitude. Technician B says MAF sensors measure exhaust flow. Who is correct?

The powertrain has become the most complex system in the vehicle.

A four-stroke engine produces a power stroke for every two revolutions of the crankshaft.

Two technicians are discussing PCV systems. Technician A says that PCV systems are connected to a port on the intake manifold. Technician B says that PCV systems prevent the fuel tank from over-pressurizing. Who is correct?

Actuators are _____.

Two technicians are discussing EFI systems. Technician A says that most modern EFI systems have one injector per cylinder. Technician B says that direct injection uses one central injector for the engine. Who is correct?

Two technicians are discussing engine operation. Technician A says that valve timing is critical to smooth engine operation. Technician B says that ignition timing is critical to smooth engine operation. Who is correct?

Older vehicles use a(n) _____ catalytic converter.