Crankshaft Sensor: Notes

The crankshaft sensor is a primary input to the EMS2000. It is used to determine the speed and position of the engine crankshaft. The sensor is a Hall Effect device. This provides a digital electrical signal that is created as the reluctor ring targets pass the sensor. The reluctor ring tooth pattern consists of 58 targets and a space of two missing teeth grouped together (6° tooth intervals). As the engine rotates the sensor output enables the EMS2000 to determine the crankshaft position and speed.

The missing teeth are essential for correct engine operation. They are used by the EMS2000 as an angular reference point. This information is used to determine:

• Fuel management
• Misfire detection
• RPM

Fig 1: Crankshaft Sensor

Courtesy of BMW OF NORTH AMERICA, INC.

Fig 2: Crankshaft tone Wheel

Courtesy of BMW OF NORTH AMERICA, INC.

Fig 3: Normal Crank Signal Waveform

Courtesy of BMW OF NORTH AMERICA, INC.

Fig 4: Engine Misfire Waveform

Courtesy of BMW OF NORTH AMERICA, INC.