One Better Model of Vehicle Turbocharged Diesel Engine than VNT Turbo

摘要

In the internal combustion engine, about 25%-40% of the energy released by burned fuel is taken away by the exhaust gas. The part of the usable energy in the exhaust can be used in the turbocharged engine. So, at present, turbocharged diesel engine hasn't made full use of exhaust gas energy. The authors propose a model of the 4-stroke turbocharged diesel engine of split exhausting system. Adding a rapidly on-and-off exhaust control valve between exhaust passage and manifold in the 4-stroke turbocharged diesel engine can improve the utilization rate of the usable energy in the exhaust. By utilizing the mean effective pressure (MEP), this paper is to calculate the maximum usable energy, the energy provided by exhaust and the energy required by intake. The results gets that the new type of exhausting system can help engine to increase usage rate of the exhaust gas energy to around 20% at the rated condition compared to the existing vehicle diesel engines with VNT. In a word, the new model can decrease fuel consumption by 5% than VNT turbo at the rated condition. Compared to VNT turbo, the optimized new model can lower fuel consumption not only at the rated condition, but at the max torque condition as well. It can decrease fuel consumption by 6% at the rated condition and can decrease fuel consumption by 2.5% at the max torque condition approximately.