内燃机低碳清洁燃烧是提高能源利用率和降低排放的重要途径，天然气和甲醇协同燃烧在内燃机上的应用是实现低碳清洁燃烧的有效途径。本项目通过开发缸内直喷甲醇、进气道喷射天然气的双燃料发动机电控系统，对双燃料发动机性能、燃烧和排放展开多参数耦合性实验研究。通过天然气和甲醇的复合喷射调控，形成火花塞区域局部富甲醇，燃烧室壁附近富天然气的混合气分层分布，阐明缸内直喷甲醇对加快天然气的燃烧速度、降低热负荷、抑制爆震的机理。研究天然气和甲醇混合气的基础燃烧特性（层流火焰速度和着火延迟期）并获得骨架机理。基于骨架机理通过数值模拟的方法研究甲醇喷射量、喷射压力、喷射正时等参数对混合气的形成、火核的生成、火焰的传播、污染物的生成及稀燃能力拓展的作用规律。阐明缸内分层下的天然气和甲醇的协同燃烧机理，为发动机台架燃烧现象的解释提供支撑，也为高效率低污染点燃式发动机燃烧调控提供基础数据、方案优化和技术路径。

Low carbon and clean combustion is key route to increase energy utilization efficiency and decrease emissions of engines, while the application of natural gas and methanol mixture in internal combustion engine is an effective approach to realize this task. This project will experimentally study the performance, combustion and emission characteristics of natural gas/methanol dual-fuel engine based on a methanol direct-injection and natural gas port-injection electronic control system. Through regulating the injection of natural gas and methanol, rich methanol mixture will be formed near the area of spark plug, rich natural gas mixture will be formed near the combustion chamber wall. The effects of burning velocity acceleration, heat reduction, and knock suppression will be quantitatively analyzed. A skeleton mechanism of natural gas and methanol mixture will be developed based on studying the basic combustion characteristics (laminar flame speed and ignition delay) of the mixtures. The effects of methanol injection quality, injection pressure and injection timing on mixture formation, nuclei formation and propagation, emission formation, as well as lean burn capability will be studied by numerical simulation. The collaborative combustion of natural gas and methanol under various methanol injection, flow and stratification will be quantitatively evaluated. The research not only can provide support for explaining the experimental results, but also can provide the database, optimization and technological route for engine combustion.