Abstract: A fuel delivery system for supplying liquid gas fuel to an engine is disclosed. The fuel can be supplied solely to the engine or together with diesel fuel. The fuel delivery system includes an injector (20) for receiving the liquid gas, and for ejecting the liquid gas in vapour form to the engine E. A bubble preventing mechanism (40, 44, 48; 8, 203, 209, 208) is supplied for preventing the liquid gas from bubbling or boiling in the injector which would impair the ejection of fuel from the injector. The preventing means comprises cooling means which may use a coolant to cool the injector. In one embodiment, the coolant is in the form of bubbled vapour which is directed away from the injector (20) and enters a chamber (206) in which the injector (20) is located, so that the vapour cools the injector (20). The vapour (20) can pass to a vapour block (208) for supply to the intake air of the engine so the vapour is supplied back to the engine together with fuel ejected by the injector (20).

Abstract: A fuel delivery system for an engine is disclosed which includes an injector (20) and a housing (3) for supporting a fuel injector (20). A regulator (202, 313) is provided for regulating the pressure of fluid in the housing to maintain the pressure at about supply pressure, and the pressure downstream of the regulator at a low pressure so that fuel which passes the regulator is able to evaporate. The evaporated fuel is supplied to a heater (250) to heat the fuel, and the vapour is supplied to a vapour injector (260) for injection into the engine. The passage of the liquid petroleum gas fuel through the housing (3) cools the injector (20) to maintain the fuel in a liquid state, and therefore prevent boiling of the vapour within the injector.