CRANK SHAFT SESNSOR (SIEMENS SYSTEM)
The sensor with its two legs links to the ECU, which can send instantaneous Engine RPM as a pseudo-sinusoidal waveform information to the ECU. This sensor is positioned just above the head of the flywheel gear wheels. The end part of this sensitive induction sensor, which has a permanent magnet unit and a coil, is a few millimeters away from the flywheel gear wheels, which is slightly ahead of the main flywheel of the engine. This flywheel includes 60 regular gear wheels which two of them has been removed. At the time when the flywheel is rotating, each gear wheel passes through the sensor and produces a pseudo-sinusoidal pulse at the sensor which is finally sent to the ECU so the first thing that sensor declares to the ECU is the flywheel movement, which is usually caused by the automobile start. This point is the only subscription point between the automobile start process and engine injector system, and in general there is no direct relationship between them. During the flywheel rotation, when the two cleared gear wheels connected to the end of the sensor, both of number 1 and 4 pistons approach to dead point and since no signal is sent at this moment, thus the ECU by realizing the situation and activating coils and injectors, orders to spark and fuel injection and also after 180 degrees, when the piston number 2 and 3 approaches to dead point, the same action is done for them.
Visual pattern for CRANK SHAFT SENSOR (SIEMENS SYSTEM)
While removing two gear wheels instead of one more attention should be paid. Considering 60 gears, if two gears are removed the difference will be 12 degrees, it means that the ECU takes the signal 12 degrees before dead point while the static evolution of automobiles are about 8 to 10 degrees.
There are two types of gear wheels on the flywheel, which one row is to engage with the starter and the other row is to activate the Crank Shaft Sensor.
CRANK SHAFT SENSOR (SIEMENS SYSTEM) Tasks:
- Declaring the move of the flywheel to the ECU.
- Declaring the high dead point to the ECU.
- Declaring Engine RPM to rotameter by the ECU.
- Providing a static evacuation to the ECU.
CRANK SHAFT SENSOR (SIEMENS SYSTEM) Problems:
- Not working the vehicle due to the failure to send signals to the ECU for fuel injection.
- Incorrect display of engine RPM when the automobile is on.
- Create CUT OFF mode before reaching the engine RPM to the red line.
- Static or non-moving rotameter from a specific engine RPM.
Note: In vehicles which have Cam Shaft Sensor, If the Crank Shaft Sensor fails, the engine RPM does not go up from 3.5-4.5