Abstract:

The electro-hydraulic variable valve actuation (VVA) system ensures variable valve timing and lift, and expends a lot of energy. To improve the energy efficiency of VVA, this paper introduces an energy recovery system (ERS). An accumulator was used to store the surplus, otherwise wasted energy of the discharged oil from the cylinder, so the accumulated pressure of this accumulator was guaranteed the lower energy consumption of the main pump. The valve timing and lift was optimized in GT-power model to achieve the minimum Basic Specific Fuel Consumption (BSFC) of the engine with this VVA system. The results show that the addition of ERS adjusts the timing and lift of the valve flexibly and decreases the VVA energy consumption with a 7% - 11% of engine power increasing and a 6% - 9% of economy increasing.

Key words: engine, energy recovery system (ERS), variable valve actuation (VVA), brake specific fuel consumption (BSFC), GT-power model