SUCTION CONTROLLED PUMP FOR HEUI SYSTEMS
First Claim
1. In an internal combustion engine having a hydraulically-actuated electronically-controlled fuel injection system of the type including a fuel injector valving high pressure fluid in response to commands from an ECM to timely inject a metered quantity of fuel into the engine'"'"'s combustion chamber;
- the injector in fluid communication with the outlet of a high pressure pump having an inlet in fluid communication with a low pressure pump;
the improvement comprising;
a high pressure pump having a housing and a plurality of piston bores within the housing;
a piston within each piston bore having one end in contact with a formed shaft portion rotatable relative to the housing, each piston movable in its piston bore to uncover and cover a suction opening of set area and pump fluid at its opposite end through a discharge vent opening in the cylinder;
a check valve at each discharge vent opening and each discharge vent opening in fluid communication with the pump outlet whereby the flow of fluid pumped by the pump is generally constant throughout the operating range of the pump.
1 Assignment
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Accused Products
Abstract
A HEUI system uses a fixed displacement, piston pump to provide a generally constant pump flow of high pressure hydraulic fluid over the operating speed range of the pump to minimize parasitic power drains on the engine. The piston pump includes an orificing suction slot to vary the pump displacement over the operating speed of the pump. A throttling valve at the pump inlet may be provided to starve inlet fluid feed if reduced flow to the injectors is additionally required.
12 Citations
36 Claims
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1. In an internal combustion engine having a hydraulically-actuated electronically-controlled fuel injection system of the type including a fuel injector valving high pressure fluid in response to commands from an ECM to timely inject a metered quantity of fuel into the engine'"'"'s combustion chamber;
- the injector in fluid communication with the outlet of a high pressure pump having an inlet in fluid communication with a low pressure pump;
the improvement comprising;
a high pressure pump having a housing and a plurality of piston bores within the housing;
a piston within each piston bore having one end in contact with a formed shaft portion rotatable relative to the housing, each piston movable in its piston bore to uncover and cover a suction opening of set area and pump fluid at its opposite end through a discharge vent opening in the cylinder;
a check valve at each discharge vent opening and each discharge vent opening in fluid communication with the pump outlet whereby the flow of fluid pumped by the pump is generally constant throughout the operating range of the pump. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 23, 24, 25, 26, 27)
- the injector in fluid communication with the outlet of a high pressure pump having an inlet in fluid communication with a low pressure pump;
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9. In a diesel engine equipped with hydraulically actuated electronically controlled unit fuel injectors having a high pressure pump in fluid communication with a high pressure rail connected to the injectors in turn utilizing solenoids actuated by an ECM to control valving of high pressure pump fluid within the injectors to timely and variably actuate the injectors, the improvement comprising:
a fixed displacement piston pump having a substantially constant flow over its operating range in unaltered fluid communication with said high pressure rail whereby an electronically controlled, pressure regulating valve controlling pump pressure in said high pressure rail is alleviated. - View Dependent Claims (10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 21, 22, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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14. A constant flow, fixed displacement, piston pump comprising:
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a non-rotatable housing containing a plurality of piston bores;
a rotatable shaft having a formed shaft portion;
a piston movable within each bore having one end extending through a bore end and in sliding contact with the formed shaft portion to impart movement to the piston while the piston'"'"'s opposite end is adjacent an outlet check valve at the opposite bore end;
the pump having a discharge chamber in fluid communication with all piston check valves and with the pump outlet; and
,each piston bore having a suction opening of set area in fluid communication with the pump inlet, the suction opening being sealed and opened by movement of each piston within its bore whereby fluid flow into the piston bore decreases in proportion to increases in shaft rotational speed after the operating speed of the pump has been reached.
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Specification