Selection of Different Strategies of Exhaust Gas Thermal Management for Optimum Fuel Economy

To tackle the problem arising due to emissions and to reduce them, complex after-treatment system is used. For efficient working of the after-treatment system it must operate at enough high temperature even at low loads for better conversion efficiency. Also, there is different temperature requirements for different catalyst used in SCR (Selective catalyst reduction) system. For this, various on engine strategies are implemented on modern diesel engines such as multiple fuel injection, late fuel injection, high fuel injection pressure and exhaust gas recirculation. Thermal management of exhaust gasses is an operating condition which must be triggered when there is need of elevated temperatures for efficient functioning of the after-treatment system. Thermal management includes SCR thermal management and regeneration. The rise in the exhaust gas temperature can be obtained by operating air handling units such as exhaust throttle valve, air throttle valve, variable geometry turbocharger, etc. Less work has been done on exhaust gas thermal management considering BSFC (Brake specific fuel consumption). The research paper gives idea about different exhaust gas thermal management strategies that can be used which will give better BSFC. The different experiments include multiple pulse injection (2 pulse, 3 pulse and 4 pulse), thermal management with exhaust throttle valve actuation, thermal management by varying rail pressure and start of injection for achieving required exhaust gas temperature.