Study On The Effect Of Different Intake Turbocharg Modes On Diesel Engine And DPF Performance

Based on China’s geographical situation and the latest implementation of China’s minzodiac emission regulations,the turbocharged diesel engine matching with the exhaust aftertreatment system can improve the diesel engine plateau adaptability and meet the emission regulations.This paper mainly studies the effects of different intake pressurization methods on the performance of diesel engine and DPF.In this paper,the characteristics of single stage supercharge diesel engine and two stage turbocharger diesel engine are compared and analyzed by building a test bench.The results show that the two stage turbocharger diesel engine has good power performance,but NO_xhigh emission,small load soot emission is higher.The diesel engine adopts the two stage turbocharger matching exhaust aftertreatment system,which has the following characteristics:intake performance,pressure rise rate,NO_x The same reduction is greater than that of single stage supercharge diesel engines.At the same time,the DPF pressure drop of two stage turbocharger diesel engine is higher than that of single turbocharged diesel engine,and the pressure drop at high altitude is higher than that at low altitude.Ash deposition has a greater effect on diesel engine performance than carbon loading.Two-stage turbocharged diesel engines have a greater impact on performance.When the single-stage pressurization is at high speed,the working state of the pressurization system is different.The overall performance of diesel engine is better with the increase of carbon load and ash component.Under the same ash deposition and carbon loading conditions,the pressure drop of a two stage turbocharger diesel engine matched with DPF is greater.The variable altitude characteristics of diesel engine and DPF were studied based on different turbocharging modes,and the structural parameters of diesel engine matching DPF were further optimized under different turbocharging modes.The results showed that the pressure drop of DPF increased with the decrease of the number of carrier mesh,and the increase rate of DPF pressure drop was faster with the increase of ash deposition and carbon load.When the ratio of inlet and outlet aperture of DPF is 1.3,the pressure drop performance is the best.A single stage supercharge diesel engine with DPF has higher collecting efficiency than a two stage turbocharger engine.According to the determined carrier structure,the effects law of carrier ratio,length-diameter ratio on diesel engine and DPF performance under different pressurization modes was further explored.The results show that the performance of diesel engines with different intake modes matching different volume DPF has no obvious effect.With the increase of carbon load and ash deposition,the lower the ratio of DPF,the faster the pressure drop rise rate.On the contrary,the stronger the ash capacity of the carrier will be.The performance of the two stage turbocharger diesel engine is more sensitive to the increase of ash loading and carbon load.With the increase of the aspect ratio of the carrier,the performance of the diesel engine is more affected,the torque has an obvious downward trend,the DPF pressure drop increases,and NO_x Reduced emissions,two stage turbocharger performance of the overall greater change.The increase of ash distribution coefficient has less effects on the small carrier with aspect ratio,stronger ash capacity,lower pressure drop and slower rise rate.There is no obvious difference in the pressure drop between different intake pressurization modes and DPF.The EGR technique is to reduce NO_x the main in-machine purification technology of emission.However,under low load and low speed conditions,diesel engine has a poor EGR introduction ability.This paper studies the EGR introduction ability of diesel engine based on the matching exhaust aftertreatment system of TST and regulated two stage turbocharger systems,and compares the performance differences between the original engine and the matching exhaust aftertreatment system.The results show that the poor ability of the two supercharging systems to introduce EGR at low speed can be improved after matching the exhaust aftertreatment system.At high speed,the EGR rate increases,the DPF pressure drop decreases,and the torque increases.At the same time,when the EGR rate is only controlled by the blade opening of high-pressure turbine,the diesel engine’s ability to introduce EGR after matching the exhaust aftertreatment system is improved.At high rotational speed,the inlet flow first increases slightly and then decreases with the opening of variable geometry turbocharger.The pressure drop of DPF increases first and then decreases with the increase of EGR rate.The pressure drop of small and high speed is higher than that of low speed.At the same EGR rate,the matching exhaust aftertreatment system diesel engine variable geometry turbocharger is more open.The smaller the variable geometry turbocharger opening is,the higher the EGR rate will be,and the worse the combustion in cylinder will be.When the opening of VGT is less than 0.4,the diesel engine economy and power performance become worse.And the exhaust loss increases.The EGR rate increased and NO_x emission decreased.The diesel engine operating characteristics of RTST matching post-processing system at varying altitude were studied.At high speed,the DPF pressure drop first increased and then decreased with the variable geometry turbocharger opening.At low speed,DPF back pressure decreases with the increase of variable geometry turbocharger opening.The torque increases first and then decreases with its opening.