คำตอบที่ 11
CRANKSHAFT POSITION SENSOR
DECRIPTION
The Crankshaft Position (CKP) sensor is located near the outer edge of the flywheel (starter ringear)
OPERATION
Engine speed and crankshaft position are provided through the CKP sensor. The sensor generates pulses that are the input sent to the Powertrain Control Module (PCM). The PCM interprets the sensor input to determine the crankshaft position. The PCM then uses this position, along with other inputs, to determine injector sequence and ignition timing.
The sensor is a hall effect device combine with an internal magnet. It is also sensitive to steel within a certain distance from it.
The flywheel/drive plate has groups of four notches at its outer edge. On 2.5L 4-cylinder engines there two sets of notches. On 4.0L 6-cylinder engines there three sets of notches.
The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM. For each engine revolution there are two groups of four pulses generated on 2.5L 4-cylinder engines. There are 3 groups of four pulses generated on 4.0L 6-cylinder engines.
The trailing edge of the fourth notch, which causes the pulse, is four degrees before top dead center (TDC) of the correspornding piston.
The engine will not operate if the PCM does not receive a CKP sensor input
