Method for reducing emissions and torque response delays in a hybrid electric vehicle

摘要

A method for operating an electric machine such that an electric auxiliary for an internal combustion engine is provided, wherein the internal combustion engine and the electric machine each generate a torque and drive a hybrid electric vehicle, so that a requested power by the electric machine in combination with the internal combustion engine wherein the internal combustion engine is a turbocharged engine (34), a supercharger engine (26) or a naturally aspirated engine (12), the method comprising the steps of: determining a magnitude of a vehicle operator requested power (P_dr_req); Determining a normalized air-fuel ratio lean limit (lambda_mfel) for the internal combustion engine (34, 26, 12); Determining a normalized air-fuel ratio fat limit (lambda_mfer) for the internal combustion engine (34, 26, 12); Using the normalized air-fuel ratio lean limit (lambda_mfel) and the normalized air-fuel ratio fat limit (lambda_mfer) to a minimum torque limit (Tq_cap_min_fast_e) and a maximum torque limit (Tq_cap_max_fast_e) of the internal combustion engine (34, 26, 12) determine using the torque limits (Tq_cap_min_fast_e; Tq_cap_max_fast_e) to generate a response to the engine torque request (Tq_eng_req) within two seconds following the torque request (Tq_eng_req) and engine exhaust emissions within a desired range which limits the emissions resulting from the normalized air-fuel ratio lean limit (lambda_mfel) and the normalized air-fuel ratio fat limit (lambda_mfer); Determining a minimum and a maximum electrical power limit of the electric machine; Using the size of the requested power (P_dr_req), the minimum and maximum torque limits (Tq_cap_min_fast_e; Tq_cap_max_fast_e) of the internal combustion engine (34, 26, 12), and the minimum and maximum electrical power limit of the electric machine, so that the requested power through the electric machine is provided in combination with the internal combustion engine within the desired period of time.