MECHANICAL SUPERCHARGED ENGINE WITH VARIABLE COMPRESSION RATIO DEVICE

摘要

PURPOSE:To prevent an engine from knocking as well as to aim at improvement in its output, by varying a compression ratio according to respective cases of supercharging and nonsupercharging, and making the compression ratio higher at the time of the nonsupercharging, improving a rate of fuel consumption, while also varying the compression ratio according to supercharging pressure at the time of the supercharging. CONSTITUTION:In an engine 1 where a mechanical supercharger 3 is installed in a suction passage 2, there is provided with a compression ratio variable device 10 as adjoined to a combustion chamber 9, and it is so constituted to do, for example, a variable displacement piston 11 is driven by a servomotor 12 in a step manner. And, the said device 10 is controlled by a control computer 13, while each signal of an engine speed and a suction air quantity out of each of sensors 14, 15 and 20 is inputted into this control computer 13. At this time, making the control computer 13 have such a control function that makes a compression ratio lower than the off time when the supercharger 3 is on, while afterward, makes the compression ratio the lower the larger in supercharging pressure.