PURPOSE: To prevent an engine with a supercharger from becoming inoperative state at the abnormal time in a titled device having main and auxiliary suction gas systems by operating a device for stopping a reverse flow from a mixture gas combustion chamber to the auxiliary system when the abnormality of the auxiliary system is detected at the decrease of supercharged pressure.
CONSTITUTION: In a suction gas device having a main suction gas system 2 which supplies new gas through a main suction gas port 4 opened at a combustion chamber 3 and an auxiliary suction gas system 5 which supplied supercharged gas through an auxiliary suction gas port 6 for operating a supercharger 18 by energizing an electromagnetic clutch 26 when a load is higher than the set load, and abnormality detector 34 which detects the decrease in the supercharged pressure in the supercharging zone due to the abnormality in the system 5 is provided. This detector 34 is composed of an abnormality discriminator 36 which inputs the outputs of an opening sensor 32 of a main throttle valve 10 and a pressure sensor 37. When the abnormality is detected, a signal is applied to a reverse flow stopper 35, thereby opening a sub throttle valve 20 in an auxiliary suction gas passage 19.
SATOU HARUHIKO
OKIMOTO HARUO
SAKURAI SHIGERU
