Cylinder wall fuel injection system for cross-scavenged, two-cycle

Abstract

A cross-scavenged, two-cycle internal combustion engine has a low-pressure, cylinder wall fuel injection system that is practical for multi-cylinder marine engines. It also reduces the amount of unburned hydrocarbons in exhaust emissions when compared to a conventional carbureted two-cycle, cross-scavenged engine. The fuel injectors are mounted through the cylinder walls so that the fuel spray contacts a deflector on the piston crown. The fuel vaporizes upon contact, and scavenging air flow from the deflector towards the spark plug electrode convects the vaporized fuel towards the spark plug electrode, thereby reducing the likelihood of short circuiting of unburned fuel through the exhaust port before the exhaust port closes and compression begins. All fuel is injected into the piston cavity before the exhaust port closes. In a multi-cylinder engine, all of the fuel injectors are mounted to have parallel spray axes and coplanar top ends, thus allowing the use of a straight fuel rail and convenient mounting techniques. Low-pressure fuel (e.g., 36 to 100 psi) is provided to the fuel rail and to the injectors, and the operation of the fuel injectors is controlled by an electronic control unit. Two fuel injectors can be provided for each cylinder to provide additional fuel injection capabilities. Various systems are disclosed for supplying pressurized fuel to the fuel rail.