In the current situation and upcoming government regulations, hybrid vehicles are very promising in terms of meeting fuel economy and stringent requirements of emission norms. Herein, hybridization will be mostly done with gasoline and CNG vehicles. As a normal practice, engine is switched off at the signal and again restart with engine start-stop technology. So, instances of engine start/stop are increased in hybrid vehicle in comparison with standard IC engine vehicle. In order to achieve smooth engine start, engine starting torque can be optimized by adjusting engine valve timing. As Electric Cam Phaser (ECP) meets valve timing target even before first engine combustion start, this is one of the critical technologies in reducing engine starting torque and time reaching to idle speed. This engine starting strategy also gives benefits in terms of reducing engine start emissions and improving fuel economy.
This paper describes selection of electric cam phaser for hybrid vehicle depending on specific engine starting and vehicle requirements. In addition to this, engine starting vibration is very critical, as its frequency increases due to multiple engine start/stop operation in hybrid vehicle either on traffic signal or on smooth highways. This work also shows detail understanding of engine start vibrations and ECP strategy to reduce these vibrations by optimizing engine valve timing.