Abstract: Supply of fuel is stopped when fuel pressure sensed by a pressure sensor provided upstream of a regulator is at a predetermined value or less to avoid abnormal combustion caused by improper adjustment of air/fuel ratio. Even slight variation of the fuel pressure is sensed by monitoring the fuel pressure in an interval after closing a fuel shut-off valve once opened to re-opening of it. In addition, an abnormal state in the fuel system is detected by comparing an accumulated value of amount of injected fuel and an estimated value of fuel consumption in the tank. Furthermore, the peak current value of the fuel injection valve is controlled so that, when the engine at a low temperature is started, lift load of the injection valve is larger than sticking force of the injection valve, thereby preventing such situation where the injection valve is frozen so that it cannot supply fuel to the engine. In this case, the engine can be smoothly started by simultaneously controlling the valve open time.

Abstract: A fuel supply mechanism for a gas combustion engine has a tank filled with a gas fuel, a fuel injector having a fuel injection valve mounted on the gas combustion engine, a pipe for supplying the gas fuel from the tank to the fuel injector, a gas fuel cutoff valve in the pipe for cutting off the gas fuel flowing through the pipe, a gas fuel state detector for detecting a state of the gas fuel, and a control unit responsive to a detected signal from the gas fuel state detector for controlling the gas fuel cutoff valve and the fuel injection valve.

Abstract: An internal combustion engine intake device having a high-speed intake passage for high-speed operation and a low-speed intake passage for a low-speed operation of the engine. Each high- and low-speed intake passage is connected to an intake port and valve hole of each cylinder of the engine. An intake box is connected to the upstream ends of the high- and low-speed intake passages and has in inlet coupled to a throttle body having a throttle valve operable in response to throttle operation by the driver. Control valves are disposed in each high- and low-speed intake passage for individually controlling the flow passage areas and the valves are operated to provide the optimum intake air flow.