Which sensor measures engine speed in modern gasoline engines?

The crankshaft position sensor is the component responsible for measuring engine speed in modern gasoline engines. This sensor detects the position and rotational speed of the crankshaft, which is crucial for the engine control unit (ECU) to manage various engine functions, including fuel injection timing and ignition timing.

The crankshaft rotates at a speed proportional to the engine speed, and by monitoring this parameter, the ECU can optimize engine performance and efficiency. Accurate engine speed information is essential for smooth operation and effective emissions control.

In contrast, other sensors mentioned, such as the camshaft position sensor, play specific roles in determining the position of the camshaft and timing of the valve events, while the mass airflow sensor measures the amount of airflow entering the engine, critical for fuel-air mixture calculations. The throttle position sensor provides feedback on the position of the throttle plate, affecting air intake. However, none of these sensors directly measure the engine's rotational speed like the crankshaft position sensor does.