| 摘要 |
<p>PURPOSE:To utilize blow-down energy in exhaust gas so effectively as well as to improve the extent of supercharging efficiency at the time of low-speed running, by dividing an exhaust passage at each cylinder into two parts, one for low speed use and the other for high speed use, and opening either of these exhaust passages at early timing. CONSTITUTION:An engine E consisting of plural cylinders #1-#4 is provided with a turbosupercharger 9 which couples a blower 6 installed alongside of a suction passage 5 with a turbine 7 to be driven by exhaust gas flowing down inside an exhaust passage 10 through a turbine output shaft 8. In this case, an exhaust passage of these cylinders #1-#4 is divided into two parts 10P and 10S for low-speed and high speed each, forming these exhaust passages 10P and 10S in two scroll chambers 7P and 7S of the turbine 7. Then, an exhaust valve opening or closing a low-speed exhaust port 12P, where the low speed exhaust passage 10P is interconnected, is opened as early as the specified timing as compared with the open timing of an exhaust valve opening or closing the high-speed exhaust port 12S where the high-speed exhaust passage 19S is interconnected.</p> |
