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根据柴油机燃烧过程中气缸内压力的变化计算燃烧放热率可以对燃烧过程有一个总 体了解，使有可能进一步改进机器的性能。但是这种计算的工作量很大，而且已有的计 算方法都没有准确地计入燃烧过程中气缸充量分子量的变化。本文所提出的方法利用电 子计算机快速的特点，用逐次接近反复迭代比较精确地计入了燃烧过程中充量分子量的 变化。计算结果表明，用不计分子量变化的方法所得到的放热率最大值可能有－１０％的 误差。 本文还根据气缸充量热量变化规律提出一个估计燃烧终点的方法，因而便于比较不 同工况的燃烧情况。这种方法所估计的燃烧终点误差在６°～８°曲轴转角范围内。此外， 文中也对做为计算基础的压力变化过程常见的测量误差（例如压力另线漂移和压力记录 角度滞后等）可能带来的计算误差进行了一些讨论。
Calculating the heat release rate from the change in cylinder pressure during combustion of the diesel engine gives a general idea of the combustion process and makes it possible to further improve the performance of the machine. However, this calculation is very heavy workload, and the existing calculation methods do not accurately account for changes in the cylinder charge molecular weight during combustion. The proposed method utilizes the fast character of electronic computers and accurately approximates the change of charge molecular weight during the combustion process by approaching repeated iterations one after another. The calculation results show that there is a -10% error in the maximum heat release rate obtained by the method without considering the molecular weight change. In this paper, a method of estimating the end of combustion is proposed according to the law of cylinder charge heat, which makes it easier to compare the combustion conditions of different working conditions. The estimated end-of-combustion error for this method is within the crank angle range of 6 ° to 8 °. In addition, some calculation errors that may be caused by measurement errors (such as pressure line drift and pressure recording angle lag, etc.) that are common to the pressure change process based on calculation are also discussed in this paper.