14 June 2000
Westport Innovations Inc. announced that it was granted its seventh US patent relating to fuel systems for low-emissions, high-compression dual fuel diesel engines. The patent #6,073,862, titled “Gaseous And Liquid Fuel Injector”, reveals a design of a hydraulically actuated dual fuel injector for injecting controlled quantities of two fuels into an internal combustion diesel engine.
The first two applications of this patented injector technology have been for two engines manufactured by Cummins. The engines under development are for on-road, Class 8 heavy-duty trucks and for high-horsepower applications such as electric power generation. Westport retains all rights to the injector technology, which it developed under two separate agreements with Cummins.
The patented injector incorporates two electronically governed actuators, for opening and closing control valves, one for natural gas fuel and one for diesel ignition pilot. An earlier Westport patent covered fuel injectors using only one actuator, to control the flow of both natural gas fuel and ignition pilot. The addition of a second actuator allows Westport to more effectively optimize the performance and emissions of the natural gas engine while minimizing the amount of diesel pilot.
Also covered by the new patent is a new method for controlling the opening and closing of the injection valves. In its previous engine program, Westport relied on injector-mounted mechanical actuation. Westport has now introduced common rail design features. Common rail technology with electronic control permits better fuel economy and lower emissions than current technologies.
Westport has been developing a high pressure direct injection (HPDI) dual fuel technology, which is intended to lower emissions while retaining diesel's power, performance and fuel economy characteristics. In the engine cylinder, the natural gas is ignited by a separate, prior injection of a small amount of diesel fuel. The diesel pilot and the natural gas fuel are both introduced through the same injector.