| 摘要 |
PROBLEM TO BE SOLVED: To effectively use CNG fuel remaining in delivery pipe at a time of engine stop by quickly and surely draining off the same. SOLUTION: This cylinder direct injection CNG engine is provided with a CNG fuel cylinder 12, a cylinder injection injector 17, delivery pipe 13, fuel feed pipe 14, a high pressure regulator 15, a normally open first shut off valve 16, and has a stratified lean burn operation zone. Three way catalyst 19, occlusion reduction type NOx catalyst 20 and fuel addition injector 21 are provided in an exhaust gas passage 18. A normally close second shut off valve 23 and a pressure relief control tank 24 are provided in the fuel pipe 22. The first shut off valve 16 is closed and the second shut off valve is opened at a time of stop of the CNG engine 10, CNG fuel remaining in the delivery pipe 13 is transferred to the pressure relief control tank 24 by pressure difference and is added by the fuel addition injector 21 to be used for NOx reduction. COPYRIGHT: (C)2005,JPO&NCIPI
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