An Approach for the Objective Description of Vehicle Longitudinal Acceleration

A trend in vehicle propulsion of converting from power sources such as a naturally aspirated internal combustion engine to turbocharged engines (Downsizing), multi-mode combustion systems (stratified charged combustion, HCCI) or multi-power source propulsion systems such as hybrid power-trains, can be observed. The subsequent switching between these different combustion modes or power sources, and, more importantly, the incorporation of turbochargers (turbo-lag) can affect the driveability, i.e. the smoothness of torque provision during transient driving manoeuvres. So far there is a lack of methodologies that can quantify and objectively describe vehicle transient acceleration events from a driver's point of perception. Thus an approach was developed while incorporating the acceleration transducers of men, the vestibular apparatus, into a longitudinal vehicle model with a transient engine / powertrain model. Finally the interaction between boost pressure generation, generated torque, vehicle acceleration and resulting stimulus of the driver is derived. In summary, this approach can support the development of well perceived longitudinal acceleration of vehicles.