In order to optimize the speed characteristics of a diesel engine during the loading process

the boost pressure change characteristics of a marine medium speed diesel engine with high pressure air injection at the end of the turbocharger compressor blade were studied. According to the dynamic characteristics of the diesel engine’s unbalanced torque

a speed control strategy of air-fuel ratio matching in the diesel engine transient loading process was proposed using improved PID control method which was suitable for the time-lag characteristics of the diesel engine. Experimental results show that the control strategy of air-fuel ratio matching of the diesel engine with high pressure air injection at the end of the turbocharger compressor blade can optimize the transient speed regulation from 4.9% to 3.8%

and the speed recovery time from 3.1 s to 2.0 s during the loading process of the diesel engine at the 0% to 50% load

while at the 50% to 100% load

the transient speed regulation can be optimized from 2.9% to 2.3%

and the speed recovery time from 2.4 s to 1.8 s.