The Study Of Diesel Engine Combustion Noise Assessment And Control Strategy Based On PPCI-LTC

Response to the current emission regulations,variety of diesel combustion modes are presented and applied successively,PPCI-LTC(Partially Premixed Compression IgnitionLow temperature combustion)is one focus of the researches.Although the new diesel engine combustion mode can achieve the low emission,high efficiency target,however,because this mode choose a high EGR rate,the combustion ignition delay period extened,which increases the mixed gas and combustion pressure rise rate,worsened the diesel engine combustion noise.So lead to the diesel engine can not extened to high-load operation.So in the new combustion mode,the combustion noise control research is imminent.For DI diesel engine combustion noise control strategies,pilot injection is the most effective way,and if the PPCI-LTC mode combined with pilot injection control strategies,the performance of the diesel engine can be a better condition,so the pilot injection strategy parameters optimization become a problem to be solved.This article is the research of diesel engine combustion noise assessment and control strategy based on the new mode,analyzes the mechanism of combustion noise and the pilot injection control strategy is optimized.First of all,combined with spectrum analysis of the cylinder pressure to get the result of the cylinder pressure level,for the PPCI-LTC mode combustion noise assessment,the empirical formula method of pressure rise rate has been modified and applied.Secondly,using single-cylinder engine bench in experiment under PPCI-LTC mode,measured the cylinder pressure and heat release rate data under the different pilot injection parameters,make the assessment of combustion noise,and then the accuracy of the assessment method is verified.And get the combustion noise influence law under the different pilot injection parameters of the single-cylinder engine.Thirdly,using advanced engine analysis software GT-POWER to built the single-cylinder diesel engine model,and then the accuracy and reliability of the model was proved by the experimental data.Finally,under the simulation environment comprehensive analysis of the influence of combustion noise,NOx and Soot under different pilot and main injection time,injection quantity.The best pilot injection parameters of Single-cylinder engine control is given,also get the influence law of combustion noise,NOx and Soot under different pilot injection parameters.In view ofthe multiple injection control strategy,the impact on combustion noise,NOx and Soot are compared.