Natural gas engines have widely been developed in the world due to the decrease of oil resources and the strictness of exhaust regulations. 由于石油资源的逐渐枯竭和排放法规的日益严格，使天然气发动机在全世界得到广泛地发展。
The results show that the selected regression model is reliable, which can provide credible data for calculation of engine waste heat utilization. 结果表明，回归模型具有较高的可信度，可为天然气发动机的废热利用提供相关数据。
