一种改善船用柴油机性能的热力循环

A thermodynamic cycle for improving performance of marine diesel engine

为了改善涡轮增压柴油机的性能,本文提出了一种向缸内喷射不同工质的热力循环,建立了该循环的数学模型,推导了性能指标的计算式,给出了各种喷射参数与性能指标的关系,从理论上证明了该循环的性能得到了改善。研究表明,当柴油机的负荷较高时喷射液态工质,可以降低机械负荷和热负荷,减少NOx的排放;负荷较低时喷射气态助燃剂,可提高增压压力,改善低负荷性能。这种循环有助于提高压缩比,从而进一步改善涡轮增压柴油机的性能,较适用于船用高增压柴油机。

This study proposed a thermodynamic cycle in which different kinds of working substances are injected in a cylinder in order to improve performance of turbocharged diesel engines. The cycle mathematical model was presented and formulae of the cycle performance indices were derived. Relations between all the injection parameters and the performance indices were given. The theoretical analysis proves that the cycle performance is improved. The study shows that liquid working substance injection can decrease mechanical loads, heat load and NOx at higher loads of turbocharged diesel engine, and that gaseous supporting combustion substance injection can increase boost pressure and can improve lower-load performance at lower load conditions. In this cycle, compression ratio of turbocharged diesel engine may be increased so that the performance can be improved further. The cycle is comparatively suitable for high-degree supercharged marine diesel engines.