| 摘要 |
A dual fuel internal combustion engine which burns in a combustion chamber 16 a main charge of a gaseous fuel, for example natural gas, propane or methane, and air mixture, combustion of the main charge initiated by igniting gasoline injected directly into the combustion chamber, the liquid fuel being ignited by a spark plug 18. The gasoline may create a stratified charge. The gaseous fuel is preferably introduced by port injection so that a homogeneously premixed, preferably lean, gaseous fuel-air mixture is provided, wherein the air may be pressurised by a supercharger. Hot exhaust gases may be reintroduced into the combustion chamber, through simultaneous opening of intake and exhaust valves, so as to promote auto ignition of the gaseous fuel-air mixture. The engine may be a four-stroke or two-stroke engine. A method of operation is also claimed. The engine enables reliable ignition of a lean mixture of gaseous fuel and air without the need for a high compression ratio. |
