车用柴油机大小涡轮相继增压系统固定转速切换的试验研究

Experimental Research on Fixed Engine Speed Switching of Sequential Turbocharging System with Two Unequal Size Turbochargers for a Vehiclular Diesel Engine

针对某车用柴油机采用两台不同尺寸涡轮增压器的相继涡轮增压系统进行了试验研究。对柴油机分别采用大增压器、小增压器和大小增压器并联的3种方案进行外特性试验,通过分析试验结果初步确定了系统的两条固定转速切换线。对大小涡轮相继增压系统进行切换试验研究,并对切换过程中发动机转速的波动情况进行了分析,最终确定大增压器与小增压器相互切换的上下行转速分别为1380 r/min和1335 r/min,大增压器与大小两台增压器并联相互切换的上下行转速分别为1970 r/min和1955 r/min。最后,对固定转速切换的可靠性进行了试验验证。

An experiment of sequential turbocharging （STC） system with two unequal size turbochargers was conducted on a vehiclular diesel engine. The full-load performance of the diesel engine was measured when the engine was equipped with a small turbocharger, with a big turbocharger, and with both a small turbocharger and a big turbocharger respectively. Two fixed engine speeds for the STC system switching were determined, and the switching experiments of the STC system were performed. It is found that the up and down switching speeds between big turbocharger and small turbocharger are 1 380 r/min and 1 335 r/min respectively. And the up and down switching speeds between big turbocharger and two turbochargers are 1 970 r/min and 1 955 r/min. The reliabilities of the switching speeds were validated by experiments.