Simulation Study On The Performance Of Two-Stroke Engine Brake

In recent years,China's road transportation has developed rapidly.The annual sales of heavy trucks have increased year by year,and the problem about safety has become more serious.When a truck is going downhill,service brake should not be used frequently in case of danger.Because the temperature rises rapidly and the brake performance decreases significantly.Engine brake can generate brake power continuously,reduce the frequency of using service brake,improve the downhill speed,and ensure the safety of truck and personnel.Therefore,engine brake has become a research focus.This paper describes the working principles and realization processes of engine drag,exhaust brake,bleeder brake,decompression brake,combustion brake and two-stroke brake,and establishes the mathematical model of the working principle of two-stroke brake.Taking a 15.3L supercharged intercooled diesel engine as the research model,the simulation model of two-stroke brake was established by using GT-Power software,and the accuracy of the model was verified.Firstly,the effects of engine speed and valve operating parameters on the brake power of two-stroke brake were studied,and valve operating parameters were optimized according to the trend of brake power.The results show that the brake power of two-stroke brake improve with increase of engine speed;there are the optimal valve operating parameters at the same engine speed;the optimal valve operating parameters change regularly with increase of engine speed.Secondly,the effects of geometric compression ratio and turbocharger efficiency on the brake power of two-stroke brake were studied.The results show that the brake power improve with increase of geometric compression ratio and turbocharger efficiency.Finally,the brake power of combined two-stroke and exhaust brake was studied,and the brake power of different kinds of engine brake were compared.This paper shows that the brake power generated by two-stroke brake is high,which can provide sufficient brake power for a truck.