Fuel and Air Mixture Control: Master Engine Performance and Emissions

Question 1

Which of the following is NOT a primary function of the engine management system (EMS) in controlling the fuel and air mixture?

Accepted Answer

Measuring crankshaft position

Answer

Adjusting fuel injector pulse width

Answer

Monitoring oxygen sensor signals

Answer

Controlling EGR valve operation

Question 2

Which type of fuel injection system utilizes a high-pressure pump to deliver fuel directly into the combustion chamber?

Accepted Answer

Direct fuel injection

Answer

Port fuel injection

Answer

Throttle body injection

Answer

Multi-point fuel injection

Question 3

What is the fundamental role of an air-fuel ratio sensor?

Accepted Answer

Monitoring exhaust gas oxygen content

Answer

Measuring exhaust gas temperature

Answer

Adjusting spark plug timing

Answer

Controlling fuel flow into the engine

Question 4

Identify the option that is NOT classified as an emission control device:

Accepted Answer

Turbocharger

Answer

Catalytic converter

Answer

Exhaust gas recirculation valve

Answer

Diesel particulate filter

Question 5

For a gasoline engine, what is the optimal air-fuel ratio?

Accepted Answer

14.7:1

Answer

10.5:1

Answer

12.5:1

Answer

16:1

Question 6

Which sensor provides the engine management system with information about the engine's crankshaft position?

Accepted Answer

Crank position sensor

Answer

Cam position sensor

Answer

Knock sensor

Answer

Oxygen sensor

Question 7

What is the primary function of a fuel pressure regulator?

Accepted Answer

Maintaining stable fuel pressure in the fuel system

Answer

Preventing fuel leaks into the engine

Answer

Regulating fuel flow into fuel injectors

Answer

Filtering impurities from fuel

Question 8

What is the purpose of a MAP (manifold absolute pressure) sensor?

Accepted Answer

Measuring absolute pressure of the intake air

Answer

Measuring intake air temperature

Answer

Controlling fuel flow into the engine

Answer

Monitoring oxygen content in the exhaust gas

Question 9

Which option is NOT a factor influencing the air-fuel ratio?

Accepted Answer

Brake pedal position

Answer

Engine speed

Answer

Engine load

Answer

Ambient temperature

Question 10

Describe the role of the ECM (engine control module) in fuel and air mixture control.

Accepted Answer

Analyzing sensor data and adjusting fuel injection parameters

Answer

Monitoring the performance of the fuel system

Answer

Controlling the operation of the ignition system

Answer

Regulating the temperature of the engine

Question 11

What is the primary function of an air-fuel ratio sensor?

Accepted Answer

To measure the oxygen content in the exhaust gas

Answer

To control the amount of fuel injected

Answer

To regulate the engine's ignition timing

Answer

To monitor the temperature of the engine

Question 12

Which of the following is an emission control device?

Accepted Answer

Catalytic converter

Answer

Oxygen sensor

Answer

Mass airflow sensor

Answer

Fuel injector

Question 13

What is the ideal stoichiometric air-fuel ratio for a gasoline engine?

Accepted Answer

14.7:1

Answer

10:1

Answer

16:1

Answer

20:1

Question 14

What is the primary function of a manifold absolute pressure (MAP) sensor?

Accepted Answer

To measure the pressure in the intake manifold

Answer

To calculate the engine's air mass flow rate

Answer

To determine the engine's vacuum

Answer

To control the fuel injector duration

Question 15

Which of the following is an example of a closed-loop fuel control system?

Accepted Answer

Throttle body injection with oxygen sensor feedback

Answer

Carburetor

Answer

Port fuel injection with mass airflow sensor control

Answer

Direct injection with knock sensor monitoring

Question 16

What is the main purpose of a fuel pressure regulator?

Accepted Answer

To maintain a constant fuel pressure in the fuel rail

Answer

To control the flow rate of fuel to the injectors

Answer

To prevent fuel leakage from the fuel system

Answer

To regulate the fuel temperature

Question 17

What is the primary objective of fuel and air mixture control in an internal combustion engine?

Accepted Answer

To optimize engine performance and minimize emissions

Answer

To ensure complete combustion of the fuel

Answer

To prevent engine damage

Answer

To reduce fuel consumption

Question 18

Which sensor measures the oxygen content in the exhaust, providing feedback to the engine management system to adjust the air-fuel ratio?

Accepted Answer

Oxygen sensor

Answer

Knock sensor

Answer

Throttle position sensor

Question 19

Which of the following is **not** a type of fuel injection system typically used in modern vehicles?

Accepted Answer

Carburetor

Answer

Port fuel injection

Answer

Direct fuel injection

Answer

Throttle body injection

Question 20

The air-fuel ratio sensor is primarily responsible for:

Accepted Answer

Measuring the oxygen content in the exhaust gases

Answer

Adjusting the timing of the spark plugs

Answer

Controlling the fuel injector pulse width

Answer

Monitoring the temperature of the catalytic converter

Question 21

Which of the following is **not** considered an emission control device?

Accepted Answer

Fuel injector

Answer

Catalytic converter

Answer

Oxygen sensor

Answer

Exhaust gas recirculation system

Question 22

The ideal stoichiometric air-fuel ratio for gasoline engines is approximately:

Accepted Answer

14.7:1

Answer

12:1

Answer

16:1

Answer

18:1

Question 23

The primary purpose of an oxygen sensor in an engine management system is to:

Accepted Answer

Measure the oxygen content in the exhaust gases

Answer

Control the fuel injector pulse width

Answer

Monitor the temperature of the catalytic converter

Answer

Adjust the timing of the spark plugs

Question 24

Which of the following is **not** a factor that can affect the air-fuel ratio in an internal combustion engine?

Accepted Answer

Tire pressure

Answer

Engine load

Answer

Engine speed

Answer

Ambient temperature

Question 25

In modern engines with electronic fuel injection, what is the main purpose of knock sensors?

Accepted Answer

Detect engine knock and adjust ignition timing to prevent damage

Answer

Measure air-fuel ratio and adjust fuel delivery

Answer

Monitor engine temperature and activate cooling fans

Answer

Detect misfires and disable spark plugs

Question 26

What environmental problem can be caused by an engine's fuel and air mixture being out of balance?

Accepted Answer

Higher greenhouse gas emissions

Answer

Better fuel efficiency

Answer

Increased engine power

Question 27

When troubleshooting fuel and air mixture control system issues, what is the main purpose of using a scan tool?

Accepted Answer

Monitoring live data and system parameters

Answer

Resetting the engine control module

Answer

Performing component activation tests

Answer

Reprogramming the engine control unit

Question 28

Which of the following is **not** a type of fuel injection system used in automotive engines?

Accepted Answer

Carburetion

Answer

Throttle body injection (TBI)

Answer

Multi-port fuel injection (MPFI)

Answer

Direct injection (DI)

Question 29

What is the primary function of an air-fuel ratio sensor in an automotive engine management system?

Accepted Answer

To control the air-fuel mixture delivered to the engine

Answer

To measure the amount of unburned fuel in the exhaust

Answer

To detect engine misfires

Answer

To measure the temperature of the intake air

Question 30

Which of the following is a common emission control device used in gasoline-powered vehicles to reduce harmful emissions?

Accepted Answer

Catalytic converter

Answer

Particulate filter

Answer

Nitrogen oxide (NOx) trap

Answer

Diesel particulate filter (DPF)

Question 31

What is the stoichiometric air-fuel ratio for a typical gasoline engine?

Accepted Answer

14.7:1

Answer

10.5:1

Answer

12.5:1

Answer

16:1

Question 32

What is the purpose of a fuel pressure regulator in an automotive fuel system?

Accepted Answer

To maintain a constant fuel pressure in the fuel rail

Answer

To control the amount of fuel delivered to the injectors

Answer

To prevent fuel vapor lock

Answer

To filter impurities from the fuel

Question 33

Which of the following sensors is primarily used to detect engine knock in modern vehicles?

Accepted Answer

Knock sensor

Answer

Oxygen sensor

Answer

Mass airflow sensor

Answer

Manifold absolute pressure (MAP) sensor

Question 34

Which fuel injection system injects fuel directly into the combustion chamber?

Accepted Answer

Direct injection

Answer

Port fuel injection

Answer

Throttle body injection

Answer

Multiport fuel injection

Question 35

What is the primary purpose of an air-fuel ratio sensor?

Accepted Answer

Measure the oxygen content in the exhaust gas

Answer

Control the duration of fuel injection

Answer

Monitor the ignition timing

Answer

Detect engine misfires

Question 36

Which emission control device is designed to reduce nitrogen oxide emissions?

Accepted Answer

SCR system

Answer

Catalytic converter

Answer

Particulate filter

Answer

EGR valve

Question 37

What is the stoichiometric air-fuel ratio for a gasoline engine?

Accepted Answer

14.7:1

Answer

12.5:1

Answer

16:1

Answer

18:1

Question 38

Which sensor provides the engine control module with information about engine load?

Accepted Answer

Throttle position sensor

Answer

Mass airflow sensor

Answer

Knock sensor

Answer

Oxygen sensor

Question 39

What is the primary function of a fuel pressure regulator?

Accepted Answer

Maintain a constant fuel pressure in the fuel rail

Answer

Control the fuel flow rate

Answer

Prevent fuel starvation

Answer

Protect the fuel system from overpressure

Question 40

Which type of fuel injector is most commonly used in modern gasoline engines?

Accepted Answer

Poppet-type injector

Answer

Pintle-type injector

Answer

Hydraulic injector

Answer

Mechanical injector

Question 41

Which component is responsible for controlling the timing of ignition?

Accepted Answer

Engine Control Module (ECM)

Answer

Distributor

Answer

Ignition coil

Answer

Knock sensor

Question 42

What is the primary function of the throttle body in fuel and air mixture control?

Accepted Answer

Controls airflow into the engine

Answer

Injects fuel into the intake manifold

Answer

Monitors engine speed

Answer

Adjusts the spark timing

Question 43

Which component is not a part of a fuel injection system in an automobile engine?

Accepted Answer

Air Filter

Answer

Fuel Injector

Answer

Fuel Pump

Answer

Fuel Rail

Question 44

What is the main purpose of the fuel trim system in an engine management system?

Accepted Answer

Optimizes fuel delivery to maintain the ideal air-fuel ratio.

Answer

Turns off fuel injectors when the engine is idling.

Answer

Adjusts ignition timing to account for fuel quality differences.

Answer

Monitors oxygen levels in the exhaust gases.

Question 45

Which type of fuel injection system injects fuel directly into the cylinder, near the piston?

Accepted Answer

Direct Injection

Answer

Throttle Body Injection

Answer

Carburetor

Answer

Port Injection

Question 46

What is the ideal stoichiometric air-fuel ratio for complete combustion in a gasoline engine?

Accepted Answer

14.7:1

Answer

12.5:1

Answer

16.2:1

Question 47

Which sensor measures the oxygen content in the exhaust gas to provide feedback to the engine control module (ECM)?

Accepted Answer

Oxygen Sensor

Answer

Manifold Absolute Pressure Sensor

Answer

Knock Sensor

Answer

Throttle Position Sensor

Question 48

What is the primary purpose of a catalytic converter?

Accepted Answer

Reduce harmful emissions in the exhaust gas

Answer

Increase engine power

Answer

Control ignition timing

Answer

Improve fuel efficiency

Question 49

What is the primary function of the throttle body in electronic fuel injection systems?

Accepted Answer

Regulates the amount of air entering the engine

Answer

Monitors engine speed

Answer

Injects fuel into the intake manifold

Question 50

What is the purpose of an idle air control valve?

Accepted Answer

Controls the idle speed of the engine

Answer

Adjusts the air-fuel ratio

Answer

Detects engine load

Answer

Monitors oxygen levels in the exhaust

Question 51

What is the primary role of the electronic control module (ECM) in fuel and air mixture control?

Accepted Answer

Manages fuel injection and ignition timing based on sensor inputs

Answer

Monitors engine temperature

Answer

Transmits power to the transmission

Answer

Lubricates engine components