Optimal engine torque management for reducing driveline clunk using time-dependent metamodels

Abstract

Driveline clunk negatively affects the perceived vehicle quality and must be minimised. This is usually achieved using engine torque management which must be balanced against throttle response. In practice, the engine torque rate of rise is calibrated manually. This paper describes a methodology for calibrating the engine torque to minimise the clunk disturbance, while still meeting throttle response constraints. Using a set of engine torque profiles and the corresponding turbine speed responses, a time-dependent metamodel is created using principal component analysis and kriging. The metamodel predicts the turbine speed response due to any engine torque profile and is used in a subsequent optimisation to minimise a clunk disturbance measure while still meeting the throttle response target. The optimal engine torque profile and corresponding turbine speed were successfully validated experimentally. We reduced the clunk disturbance by 33% while improving the throttle response by 11%.