Combustion engine with fuel injection system, and a spray valve fo r such an engine

Claim 1

Fuel system for a combustion engine having a cylinder with an air inlet passage comprising a fuel spray valve having a fuel injection nozzle for spraying fuel into the cylinder air inlet passage and having a fuel spray valve passage leading to the nozzle, means for mounting the fuel spray valve to position the nozzle to open into the cylinder air inlet passage adjacent the cylinder, a fuel pump for providing fuel under pressure to the fuel spray valve passage to be sprayed from the fuel spray valve nozzle, and a fuel heating device connectable to an electrical power supply and disposed adjacent to the valve to be energized for heating the fuel to enhance finer spraying thereof by the fuel spray valve nozzle, the fuel heating device comprising means defining a spiral fuel flow path of selected length connected to and coaxial with the fuel spray valve passage to dispose said selected length of fuel flow path closely adjacent to the fuel spray valve passage, and a fuel heating element comprising a thermistor of a ceramic material of positive temperature coefficient of resistivity arranged to heat said selected length of the spiral fuel flow path to transfer heat to the fuel flowing in the spiral fuel flow path throughout said selected length of the spiral fuel flow path to substantially heat the fuel at a location closely adjacent to the fuel spray valve passage to enhance vaporizing of fuel being sprayed from the valve nozzle.