| 摘要 |
PURPOSE:To reduce a constriction loss through the jet port of an auxiliary chamber and further to ensure a sufficient combustion rate to promote later stage combustion, by forming the jet port of the auxiliary chamber with several stage jet port sections, and by setting the minimum areas at the top dead centers of the jet ports sections and the angles of upper and lower parallel surfaces of the jet port sections in specific orders. CONSTITUTION:The variable jet port of an auxiliary chamber is formed such that a projecting part 10 of a piston 7 which ascends is inserted into the jet section of lower part of a nozzle section 9 in the auxiliary chamber to form a jet port. Further, gas is jetted from an auxiliary combustion chamber 2 to a main combustion chamber 1 upon compression and from the main combustion chamber 1 to the auxiliary combustion chamber 2 upon expansion with suitable speeds and directions, respectively. At this time the angles alpha, beta of jet port sections A, B and areas FJAO, FJBP are selected as alpha<beta, FJAO<=FJBO. Then, the flow area FJ from the auxiliary combustion chamber 2 to a main combustion chamber 1 is not abruptly enlarged upon descent of the piston so that a suitable constriction may be held to ensure a sufficient jet stream speed. Accordingly, the later half combustion rate is sufficiently ensured to realize a satisfactory combustion performance. |
