船用中速柴油机加载过程油气匹配控制策略研究

Study on the Air-Fuel Ratio Matching Strategy of a Marine Medium Speed Diesel Engine during its Loading Process

根据柴油机加载过程转速调节受增压空气压力抑制的特点,研究了船用中速柴油机瞬态加载过程用压气机叶片端高压空气喷射方式进行补气的增压压力变化特性,并根据柴油机力矩不均衡产生的动态变化特点,结合适应柴油机时滞特性的比例-积分-微分(PID)控制方法,形成了柴油机瞬态加载过程油气匹配的调速控制策略。经某船用中速柴油机台架试验验证证实,采用加载过程压气机叶片端高压空气喷射方式进行补气的油气匹配控制策略,使柴油机0%~50%负荷加载过程瞬态调速率从4.9%优化至3.8%,稳定时间从3.1s优化至2.0s;50%~100%负荷加载过程瞬态调速率从2.9%优化至2.3%,稳定时间从2.4s优化至1.8s。

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.