New Challenges For Engine Sensors In Hybrid Powertrains

Sensors in combustion engines face unique challenges in hybrid cars.

- Klaus Grambichler

Modern crankshaft sensors must differentiate between intentional rotation while the engine is running and random crankshaft movements, such as those caused by vibrations during purely electric driving. This differentiation is the only way, for example, to ensure a smooth transition when switching between the combustion engine and electric motor. And only in this way can components such as the starter and the battery be dimensioned most cost-effectively. In this article, Infineon describes corresponding algorithms in the latest XENSIV™ crankshaft sensor.

Car manufacturers across the globe are expanding their portfolio of drive systems. Even looking beyond the fuel cells and synthetic fuels of tomorrow, there is still a vast number of hybrid options spanning the gap between combustion engines and electric motors. These options range from stop-start combustion engines, where the motor shuts off for a few seconds at a red light and then does a cold start. The plug-in hybrids that can quickly drive 50 kilometres in all-electric mode before the combustion engine kicks in as the battery runs low. It could also be when the vehicle is travelling at high speed on a highway.

Two different implementations of even the most modern stop-start systems have already reached the market. In one instance, the combustion engine starts again as if it had been still for an hour and not driven. The second solution monitors the movement of the engine as it comes to a stop. When the engine starts up, the car already knows the crankshaft position and the cylinder to be fired.