Study on low temperature starting strategy for high power density diesel engines

During low-temperature starting, the high viscosity and poor fluidity of diesel engine lubricating oil make it difficult to be timely replenished to the friction pair, leading to the problems of starting difficulties and wear during cold starting. To address this issue, this study completed a simulation verification work through a bench test, and carried out a transient simulation of lubricating system oil filling in the range of 1–5 s starting time and −20°C to 80°C lubricating oil temperature to obtain the transient filling characteristics of the lubrication system oil path and the friction characteristics of the bearing. The results show that extending the starting time can effectively reduce the average dry sliding speed of the bearing, thereby reducing the frictional wear of the critical friction pairs during starting; when the oil temperature is between 20°C and 30°C, the average dry sliding speed of the bearing is low and the dry sliding distance is the shortest. The research results of this study are conducive to in-depth analysis of the lubrication oil filling mechanism during cold starting, and to determine a reasonable cold starting strategy from the perspective of lubrication.