Start-up method for a vehicle with a hybrid propulsion system

A start-up method for heating a selective catalytic reduction (SCR) module in a hybrid propulsion system of a vehicle, said system comprising an electric motor operatively connected to an internal combustion engine producing exhaust gas, said electric motor and said internal combustion engine being operable to power said vehicle, and said internal combustion engine being in fluid communication with an exhaust aftertreatment system (EATS) having an exhaust passage and comprising the SCR module, said SCR module being disposed in said exhaust passage downstream of said engine and said electric motor, comprising the steps of:

• operating the engine in a start-up mode with a torque restriction on the engine, allowing the SCR module to convert NOx emission;
• performing a high pressure exhaust gas recirculation (EGR) of exhaust gases transported in the exhaust passage downstream of the engine, while further comprising terminating the high pressure EGR;
• supplying a surplus amount of a reducing agent to the exhaust gas at a position between the engine and the SCR module, the surplus amount of the reducing agent being larger than a required amount of reducing agent for converting the NOx emission from the engine;
• heating said SCR module to a working temperature;
• terminating the start-up mode including switching from said high pressure EGR to a low pressure EGR, while changing from supplying the surplus amount of the reducing agent to the required amount of reducing agent for converting NOx emission from the engine, thereby terminating the torque restriction on the engine and the supply of the surplus amount of the reducing agent.