Design of CVT-Based Hybrid Passenger Cars

In this paper, the hybridization of a small passenger car equipped with a continuously variable transmission (CVT) is investigated. Designing a hybrid drive train is a multiobjective design problem. The main design objectives are fuel consumption, emissions, and performance. However, it is difficult to find a global optimal integral design solution due to the interdependence of design choices (parameters) regarding the drive-train topology, component sizes, component technologies, and control strategy, as well as the unknown sensitivity of the design objectives to the design parameters. In this paper, a parametric optimization procedure is presented to solve the design problem, where the main design objective is fuel consumption. The effects of parameter variation on fuel consumption have been investigated. Furthermore, a reduced hybrid drive-train model is introduced, with which the effects of design parameter variation is very quickly studied with an average error of less than 1.6%.