针对耦合余热回收式甲醇气辅喷射系统的甲醇-柴油双燃料发动机，首先基于能量流建立余热回收评价指标，然后根据评价指标探究气辅压力和甲醇替代率两个关键参数对甲醇燃料利用率的影响。结果表明：在气辅温度为80 ℃、甲醇替代率为40%的试验条件下，随着气辅压力的升高，甲醇燃料利用率逐渐升高。气辅压力在0.1~0.2 MPa范围内，随着气辅压力的升高，排气能量增加，使混合气吸热效率增加，甲醇从混合气吸收的能量增加，甲醇的燃料利用率从50.19%提高到95.26%。在气辅温度为80 ℃，气辅压力为0.15 MPa的试验条件下，随着甲醇替代率的升高，甲醇燃料利用率逐渐降低，在甲醇替代率为10%时甲醇燃料利用率为97.23%，在甲醇替代率为50%时其降低到62.95%。

For a methanol/diesel dual-fuel engine incorporating a waste heat recovery-coupled methanol gas-assisted injection system, waste heat recovery evaluation metrics were established according to energy flow analysis. These metrics assessed the impacts of gas-assisted pressure and methanol substitution ratio on methanol fuel utilization efficiency. The results indicate that methanol utilization efficiency increases with the rise of gas-assisted pressure at a constant gas-assisted temperature of 80 ℃ and methanol substitution ratio of 40%. Within the 0.1-0.2 MPa gas-assisted pressure range, the exhaust energy increase accompanied by the gas-assisted pressure increase leads to higher heat absorption efficiency of mixture and greater energy absorbed by methanol from the mixture. Consequently, the methanol fuel utilization rate rises from 50.19% to 95.26%. Under test conditions with a gas-assisted temperature of 80 ℃ and a gas-assisted pressure of 0.15 MPa, the methanol fuel utilization rate gradually decreases as the methanol substitution rate increases. The methanol fuel utilization rate is 97.23% when the methanol substitution rate is 10% and decreases to 62.95% when the methanol substitution rate is 50%.