High pressure fuel pump for internal combustion engine
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorsHiroshi Hasegawa, Takeo Yoshida
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Abstract
A high pressure pump for an engine fuel injection system, wherein the pump has a plurality of positive displacement pumping devices that are operating so that their delivery cycles overlap and so that the instantaneous speed of the pumping devices during their delivery strokes is constant so as to minimize pressure variations in the system and avoid the necessity of having the pump being driven in synchronized relationship to the engine output shaft. This permits the use of a variable speed drive so that the pump can be driven at speed ratios depending upon engine demand and/or eliminates the necessity for positive drives to maintain synchronization. A number of embodiments showing different pump configurations are disclosed.
Claims31
A pump for a fuel injection system, comprising a plurality of positive displacement pumping devices for pumping fuel to a fuel delivery system supplying at least one fuel injector, each movable in a cycle through a suction phase during which fuel is drawn into said pumping device and a delivery phase during which fuel is pumped by said pumping device, drive means for driving said pumping devices, said drive means and said pumping devices being interrelated so that the pumping strokes of said pumping devices overlap each other, at least two of said pumping devices are always in a delivery phase, and the sum of the instantaneous speed of the pumping devices during the pumping strokes is constant.
A fuel injection system for an internal combustion engine having an output shaft, a fuel injector, a high pressure positive displacement fuel pump for pumping fuel to said fuel injector, and a variable speed transmission for driving said fuel pump from said engine output shaft without controlling the timing relationship between said engine output shaft and said high pressure fuel pump.
Dependencies are inferred from the claim text.