Patent ID: 6113361
Filing Date: 2000-09-05
Classification: F02M

Abstract:
A fuel pump for receiving fuel from an external fuel source and discharging fuel for use by a fuel utilization device, said pump comprising:a fuel-delivery device fluidly connected to the external fuel source for receiving fuel therefrom and delivering the fuel to said fuel pump;a pump body defining a cam box;a rotary drive shaft having at least one cam attached thereto and disposed within said cam box;at least one reciprocating cam follower assembly which is disposed within said cam box and driven by said cam to provide alternating fuel-in-take and fuel-pumping phases of operation of said pump; anda fuel-pressure conversion-assembly comprising,a conversion-assembly body which defines at least one first-pressure bore, a fuel circuit fluidly connected to said fuel-delivery device to receive fuel therefrom, at least one piston bore fluidly connected to said first-pressure bore, at least one second-pressure bore in selective fluid communication with said fuel circuit and an outlet port in selective fluid communication with said second-pressure bore;at least one first-pressure pumping plunger, each of said plungers being movably disposed within one of said first-pressure bores and being driven by one of said cam follower assemblies whereby fuel is delivered into said first-pressure bore during said in-take phase of operation and pumped therefrom into said piston bore during said pumping phase of operation;a converting piston disposed for reciprocal motion within said piston bore such that said piston is driven by fuel in a first direction during said pumping phase of operation in synchronism with said first-pressure plunger;a second-pressure pumping plunger movably disposed within said at least one second-pressure bore, said second-pressure plunger being driven in said first direction and in a second opposite direction under the influence of said piston during said pumping and in-take phases of operation respectively;a resilient bias member to urge said piston in said second direction such that said piston moves in said second direction during said in-take phase of operation in synchronism with said first-pressure pumping plunger;an inlet check valve for preventing the flow of fuel from said second-pressure bore into said fuel circuit device during said pumping phase of operation and for permitting the flow of fuel into said second-pressure bore during said in-take phase of operation;an outlet port fluidly connected to said second-pressure bore for discharging fuel for use by the fuel utilization device; andan outlet check valve for preventing the flow of fuel into said second-pressure bore from said outlet port and for permitting the flow of fuel from said second-pressure bore into said outlet port during said pumping phase of operation.