Abstract: A first fuel injection pulse width is provided based on engine operating conditions. The amount of fuel is necessary for one combustion stroke of the engine at one time. A second fuel injection pulse width is provided based on engine operating conditions so as to inject at one time an amount of fuel for two combustion strokes of the engine. The first fuel injection pulse width is compared with a minimum value. The first fuel injection pulse width is selected when the first fuel injection pulse width is larger than the minimum value, and otherwise, the second fuel injection pulse width is selected when the first fuel injection pulse width is smaller than the minimum value. Fuel is injected at the selected injection pulse.

Abstract: The internal combustion engine has a battery and a magneto for an ignition system of the engine. The magneto has a charge coil and a source coil for generating a first alternating current and a second alternating current, respectively. The alternating current is rectified and the rectified current is supplied to the battery for charging. The second alternating current is supplied to electric loads to be operated by the engine.

Abstract: A snowmobile has an upper hood having a plurality of air intakes, an engine provided downstream of the air intakes, and an air box having an air cleaner and communicating with an inlet port of the engine. An electronic control unit is disposed in a case which is secured to an upper wall of the air box. A deflector is disposed between the air intakes and the case so as to deflect intake air from the case.

Abstract: An engine start control system wherein the engine is restarted after the engine is scavenged without supplying of fuel from a fuel injection valve by cranking only when the engine almost stops as well as when a driver wants to scavenge. The driver's intention to scavenge a combustion chamber of the engine is detected by a control switch which the driver can turn on or off or an opening degree of a throttle valve in an intake passage when the opening degree is equal to or exceeds a predetermined value.

Abstract: An ignition device intermittently produces an ignition voltage in synchronism with speed of an engine. A fuel injection control is provided for operating a fuel injector for injecting fuel. A fuel pump for supplying fuel to the fuel injector is stopped at a time after the ignition and fuel injection stop, thereby keeping fuel pressure in a fuel supply passage.

Abstract: A motor vehicle has a continuously variable belt-drive transmission having a clutch means which engages when speed of an engine is higher than a clutch engaging speed. A plurality of basic pulse widths for injecting fuel are stored in a memory arranged in accordance with the engine speed and opening degree of a throttle valve. Some of the basic pulse widths in a speed range lower than the clutch engaging engine speed are increased for acceleration of the engine. One of the basic pulse widths is retrieved in accordance with the actual engine speed and the throttle valve opening degree, and a fuel injection pulse width is calculated based on the retrieved basic pulse width.

Abstract: A crankcase temperature sensor is provided for detecting temperature of a crankcase. A low speed basic injection pulse width is provided based on the detected crankcase temperature for low engine speed. An ordinary fuel injection pulse width is provided in accordance with engine operating conditions for ordinary engine operating condition. A comparator is provided for comparing the low speed injection pulse width and the ordinary fuel injection pulse width with each other. A larger injection pulse width is determined for injecting fuel.

Abstract: A two-cycle engine has an lubricating system for lubricating rubbing parts in a crankcase. A fuel injector is provided on a wall of an intake passage for injecting fuel toward an intake port of the engine. An oil injecting port is formed in the wall of the intake passage, and the fuel injector is provided for injecting fuel toward the port so as to mix with the lubricating oil.