SAE International Application of Model-Based Development to Engine Restart Vibration After Idling Stop 2017-01-1053

Idling stop systems are being increasingly adopted in conventional engine vehicles as well as hybrid electric vehicles to increase fuel efficiency. When the engine starts, body vibration occurs that is caused by the rigid body eigenvalues of the power plant during initial combustion. Engine restart vibration after an idling stop is caused by the input force from the transmission, and the reaction force from the drive shaft as well as the input force from the engine. This phenomenon occurs frequently when the engine is restarted from the idling stop, the vibration is increasingly annoying to passengers. Usually, the vehicle development process is carried out in accordance with the V process. The V process divides the vehicle development process into two stages. The first stage is called the vehicle design stage to determine the characteristic. The second stage is called the vehicle verification stage to verify the performance. However, we have no prediction techniques in the design stage for engine restart vibration. Therefore, engine restart vibration can only be verified in the verification stage. A technique that can predict the system and parts characteristics at the design stage is needed in recent development processes. This study develops a prediction technique for restart vibration with in-cylinder pressure prediction that can determine the required system and parts characteristics by applying model-based development from the vehicle design stage. Furthermore, this study develops a method that can properly evaluate restart vibration in order to refine the directions and frequencies of the vibration to be measured.