Abstract: A fuel injector assembly for an internal combustion engine, including: a delivery chamber (5) located within the injector assembly (1); a mass flow rate control means (50) for controlling the mass flow rate of fuel and compressed gas supplied to the delivery chamber (5), the mass flow rate being a function of the differential pressure across the mass flow rate control means (50); and valve means (9) for selectively communicating the delivery chamber (5) to the engine to deliver fuel to the engine; wherein when the valve means (9) is opened, at least compressed gas is caused to flow thereby generating a differential pressure across the mass flow rate control means such that a controlled fuel flow is provided to the engine.

Abstract: A method of determining a purge fuel mass flow rate from a fuel vapor control system to an internal combustion engine having a compressor for delivering purge gas from the fuel vapor control system to the engine. The temperature rise of the purge gas passing through the compressor is determined. Then, a specific heat ratio of the purge gas is determined as the function of the temperature rise. The purge fuel mass flow rate is determined as a function of specific heat ratio of the purge gas.

Abstract: A method of regulating gas pressure in a dual fluid fuel injection system for an internal combustion engine having at least one delivery injector, including; determining when the gas pressure supplied to the fuel injection system is above a desired level; and opening the at least one delivery injector of the dual fluid fuel injection system for a determined duration when the gas pressure is above the desired level to allow gas to be passed through the delivery injector and thereby regulate the gas pressure of the supplied gas.

Abstract: A fuel vapor handling system for a dual fluid fuel injection system, including: a fuel supply apparatus and a gas supply apparatus for respectively supplying liquid fuel and gas-vapor mixture to at least one delivery injector of the dual fluid fuel injection system, the fuel supply apparatus including a fuel pump; and a fuel vapor control device providing a fluid communication between the fuel supply apparatus downstream of the fuel pump and the gas supply apparatus to allow fuel vapor present within the fuel supply apparatus to pass to the gas supply apparatus for subsequent delivery by the at least one delivery injector. The fuel vapor device preferably allows the pressure of the liquid fuel supplied to the at least one delivery injector to be substantially equalized with the pressure of the gas supplied to the delivery injector.

Abstract: A fluid metering pump (1) is disclosed which is operated by a source of pressurised fluid, which in the case of a pump for metering fuel, may be the crankcase (37) of a two stroke, crankcase scavenged, internal combustion engine. The metered quantity of fluid displaced by the pump (1) is a function of the pressure of the pressurised fluid and time that the pressure acts on a pumping means (15) of the pump (1). Attenuation of the pressure may be achieved, especially under idle or high engine speed conditions in the case of an engine, by a throttle (35) placed in a conduit (33) communicating an actuation chamber of the pump (1) with the source of pressurised fluid, such as the crankcase of a two stroke engine.

Abstract: A gaseous fuel direct injection fuel system for a spark ignited internal combustion engine having an inlet port for admitting combustion air into a combustion chamber of the engine, the direction injection system including at least one fuel injector for directly injecting gaseous fuel into the combustion chamber, and means for supplying gaseous fuel to the fuel injector, a quantity of gaseous fuel being injected into the combustion chamber by the fuel injector, wherein at least at some operating condition thereof, the injection of the gaseous fuel is initiated after the closing of the inlet port, and wherein the injection of the gaseous fuel is completed before the compression stroke of the engine is substantially completed.

Abstract: A method of controlling operation of an internal combustion engine over part of the load or speed operational range of the engine by the use of fluid pressure available from a source associated with the operation of the engine to effect a managed control of at least one operating parameter of the engine such as engine speed or fuel delivery including fuelling rate and timing, or ignition timing. The gas pressure is preferably derived from a source where the pressure varies in relation to variations in the engine speed and/or load or from a substantially steady pressure source, applied in a selective manner to effect the control. Preferably, the fluid pressure is a gas pressure derived from the operation of the engine.

Abstract: A direct injected internal combustion engine includes a fuel injector associated with a combustion chamber; a fuel metering device to meter fuel for delivery by the fuel injector; and a gas supply in communication with the fuel injector such that the fuel is delivered from the fuel injector to the combustion chamber entrained in a gas. The gas supply is vented to atmosphere or a combustion chamber of the engine in response to sensing of an engine operating condition indicating imminent cessation of operation of the engine. Venting may be achieved, for example, by maintaining the fuel injector open or in communication with the combustion chamber prior to the stopping of the engine on sensing of the engine operating condition which may be reduction of engine speed below a predetermined value or activation of a "stop" switch.