Analytical method to evaluate fuel consumption of hybrid electric vehicles at balanced energy content of the electric storage devices

Innovative analytically based method to calculate corrected fuel consumption of parallel and series hybrid electric vehicles (HEVs) at balanced energy content of the electric storage devices is proposed and validated in the paper. The proposed analytical method is generally applicable and features highly accurate corrected fuel consumption results. It enables calculation of the corrected fuel consumption out of a single fuel consumption test run in a single analytic post-processing step. An additional fuel consumption test run might be needed to obtain highly accurate results if ratio of the energy content deviation of the electric storage devices to the energy used for vehicle propulsion over the test cycle is high. Proposed method enables consideration of non-linear energy flow changes and non-linear HEV component efficiency changes caused by the energy management strategy or by the component characteristics. The method therefore features highly accurate results out of the minimum number of fuel consumption test runs and thus optimizes workload for development or optimization of HEVs. The input data of the method are characteristic energy flows and efficiencies that are derived from the energy flows on selected energy paths of HEVs.