| 摘要 |
PURPOSE:To improve thermal efficiency by providing a subchamber opened to a combustion chamber, mounting a subchamber valve to an opening of this subchamber, opening the subchamber valve in an intermediate period of a compression stroke, and closing the subchamber valve in the end of the compression stroke or in the beginning of an explosion stroke. CONSTITUTION:A subchamber 10 is formed in an engine 1 to open a subchamber port l0a to a combustion chamber 14. A subchamber valve 11 is arranged in the subchamber port 10a opened and closed. Close timing of this subchamber valve 11 is set to ABDC160deg equal to the ignition timing so that the valve is opened about 70deg before this close timing. Thus by opening/closing the subchamber valve 11 in a compression stroke, a mixture in the combustion chamber 4 is partly confined cooled in the subchamber 10 to replace partly a mixture in the combustion chamber 4 with this cooled mixture in the next compression stroke. Accordingly, a temperature in a cylinder is decreased to improve thermal efficiency. |
