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Difficulty: MediumFuel and Air Intake Systems

Which sensor in an electronic fuel injection system directly measures the volume and density of incoming air entering the intake manifold?

  1. A
    Throttle position sensor
  2. Mass airflow sensorAnswer
  3. C
    Oxygen sensor
  4. D
    Camshaft position sensor

Answer

The mass airflow sensor directly measures the amount and density of air entering the engine intake.
The mass airflow sensor is positioned in the intake air tract between the air cleaner and the throttle plate to directly calculate the mass flow rate of air entering the engine, allowing the engine control computer to deliver the proper fuel injector pulse width.

Step-by-Step Solution

1
Identify the primary function required by the engine control module to determine fuel injection quantity.
The engine control module needs accurate measurement of incoming intake air mass to maintain the correct stoichiometric ratio.
Air density changes with temperature and pressure, requiring real-time intake measurement.
2
Evaluate the role of each sensor in the intake and engine control systems.
The mass airflow sensor is placed between the air filter and throttle body specifically to measure the mass flow rate of incoming air.
Other sensors measure valve angle, rotational timing, or post-combustion exhaust gases rather than incoming air volume.

Key Concept

Mass Airflow (MAF) Sensor Operation in Fuel and Air Intake Systems
Estimated Time:50s
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Topics

Fuel and Air Intake Systems

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