The speed-density fuel-injection system uses the sensor as the primary sensor to determine base pulse width.
A. TP (throttle position)
B. MAF (mass air flow)
C. MAP (manifold absolute pressure)
D. BARO (barometric)
The correct answer and explanation is :
The correct answer is A. TP (throttle position).
Explanation:
In a speed-density fuel-injection system, the throttle position (TP) sensor plays a critical role in determining the base pulse width of the fuel injectors, which ultimately controls the amount of fuel injected into the engine. Let’s break down why this is the case:
- Throttle Position (TP) Sensor:
- The TP sensor measures the position of the throttle valve in the intake manifold. This information is critical because it indicates how much air the engine is trying to intake. The more the throttle is opened, the greater the airflow demand.
- In a speed-density system, the TP sensor provides input to the engine control unit (ECU) to calculate the fuel needs based on the amount of air being drawn into the engine. This helps the ECU adjust the fuel injection pulse width accordingly to match the engine’s air intake, thereby optimizing the air-fuel ratio for efficient combustion.
- How the System Works:
- Speed-density systems determine the amount of fuel to inject based on a combination of air pressure (MAP sensor) and engine speed, but throttle position is used as a primary input to estimate the engine’s instantaneous load. The ECU uses the TP sensor data to infer engine load and adjusts the fuel injector pulse width, ensuring that the correct amount of fuel is injected.
- The throttle position sensor allows the ECU to adjust fuel delivery more dynamically and accurately as driving conditions change. When the throttle is suddenly opened (e.g., during acceleration), the TP sensor helps the ECU quickly adjust the fuel injection, maintaining the proper air-fuel mixture.
- Other Sensors:
- B. MAF (Mass Air Flow): While MAF sensors are important in other fuel injection systems (like those using mass airflow measurements for fueling), speed-density systems typically use a combination of other sensors, such as the MAP and TP, instead of MAF.
- C. MAP (Manifold Absolute Pressure): MAP sensors measure intake manifold pressure and are also used in speed-density systems, but they do not directly control the base pulse width on their own. They assist in calculating engine load, in conjunction with the TP sensor.
- D. BARO (Barometric): BARO sensors measure atmospheric pressure, which can help correct fuel calculations for altitude changes but do not directly influence pulse width as the TP sensor does.
Thus, the Throttle Position (TP) sensor is the primary sensor used to determine the base pulse width in a speed-density fuel injection system, ensuring the right fuel-air mixture for optimal engine performance.
