Fuel consumption and energy balance of "optimized CVT-hybrid- driveline"

Nowadays the task to diminish energy consumption and air pollution caused by road traffic occupies a key issue. One of several approaches is the hybrid driveline technology. At the Technical University Munich through a research project the "Optimized CVT-Hybrid-Powertrain" was designed and manufactured and is under investigation. This research project is run in close cooperation between university and industry (EPCOS AG, GM Powertrain Europe, ZF Friedrichshafen AG and ZF SACHS AG). The project is focused on reduction of fuel consumption at low additional cost for hybridization. The "Optimised CVT-Hybrid-Powertrain" is a full hybrid car driveline using Diesel-engine, electric motor with double layer capacitors for electric energy storage and a CVT-type transmission. Vehicle pull away is typically done by electric driving; the ic-engine is started by a fast ratio change of the CVT-transmission without additional starter. The driveline is assembled into an OPEL VECTRA vehicle for investigations on practical use and at a test rig for detailed measurement on energy flow, fuel consumption and control system behavior. Beside running the powertrain in car and on test rig investigations are also done by simulation of the hybrid system. Drivability and function of the components are shown for various situations of driving. Fuel consumption of the "Optimized CVT-Hybrid" is evaluated and discussed both for standard cycles and for specific driving courses. The energy flow through the components is analyzed and evaluated with respect to minimize energy consumption; energy losses can be detected and further saving potential can be seen.