Reciprocating plunger type fuel injection pump having electromagnetically operated control port

Claim 2

A pump for supplying pressurized fluiD which comprises: a pump housing having a pumping chamber that has an inlet port, a relief port, an injection port communicating with said engine, and means for receiving a fluid, said fluid receiving means communicating with said inlet port, said relief port and said pumping chamber; means for keeping said injection port closed below a first predetermined pressure in said pumping chamber; means for periodically pressurizing the fluid in said chamber to cause fluid entering said pumping chamber through said inlet port to periodically flow out of said pumping chamber through said relief port; and electromechanical valve means operative to open and close said relief port at predetermined intervals in response to at least one operating parameter of said engine, said electromechanical valve means including a solenoid valve having a core that has a first portion having an axial cross-sectional area that matches the configuration and size of said relief port and a second portion having a second axial cross-sectional area that is smaller than the relief port, said solenoid core mounted for axially reciprocating movement in said relief port so that in one position said first portion of said solenoid core closes said relief port and in a second position said second portion of said solenoid core opens said relief port, said solenoid core mounted so that neither end thereof terminates within said pumping chamber whereby the axial movement of said solenoid core that opens and closes said relief port is not biased by pressurized fluid within said pumping chamber, whereby each time said relief port closes, the fluid pressure in said pumping chamber attains the first predetermined pressure at which said injection port opens, whereby pressurized fluid flows from said injection port.

Claim 3

The pump as recited in claim 1 wherein said means for pressurizing fluid in said pumping chamber comprises: a piston mounted for reciprocating movement within said pump housing, said piston operable to periodically open and close said inlet port and thereby periodically apply pressure to said fluid in said pumping chamber as said plunger reciprocates, whereby when said relief port is open, fluid is pumped through said relief port and when said relief port is closed, fluid is pumped through said injection port.

Claim 4

The pump as recited in claim 2 wherein said solenoid core is mounted transverse to said pump piston.

Claim 5

The pump as recited in claim 1 wherein said solenoid core is mounted transverse to a wall of said pumping chamber so that said plunger extends into said chamber through said relief port.

Claim 6

The pump as recited in claim 2 wherein said solenoid core is mounted transverse to a wall of said pumping chamber so that said plunger extends into said chamber through said relief port.

Claim 7

A fuel injection system for an internal combustion engine of the type having a cam shaft, the system comprising: a pump housing having a pumping chamber that has an inlet port, a relief port and an injection port, said injection port communicating with said engine; means for supplying fuel to said pumping chamber through said inlet port; means for closing said injection port, said closing means including biasing means for keeping said injection port closed until a predetermined fuel pressure is attained in said pumping chamber; means responsive to the rotation of said engine cam shaft for periodically pressurizing the fuel in said chamber whereby the fuel in said chamber periodically flows out of said pumping chamber through said relief port; and electromechanical valve means operative to open and close said relief port at predetermined intervals in response to at least one operating parameter of said engine whereby each time said relief port is closed the fuel pressure in said pressure chamber attains the predetermined pressure level at which said injection port opens, thereby injecting fuel into said engine, and each time said relief port is open, said injection porT is closed, said electromechanical valve means is a solenoid valve having a plunger that has a first portion having an axial cross-sectional area that matches the configuration and size of said relief port and a second portion having a second axial cross-sectional area that is smaller than the relief port, said plunger mounted for axially reciprocating movement in said relief port so that in one position said first portion of said plunger closes said relief port and in a second position said second portion of said plunger opens said relief port, said solenoid core mounted so that neither end thereof terminates within said pumping chamber whereby the axial movement of said solenoid core that opens and closes said relief port is not biased by pressurized fluid within said pumping chamber.

Claim 8

A fuel injection system for an internal combustion engine of the type having a cam shaft, the system comprising: a pump housing having a pumping chamber that has an inlet port, a relief port and an injection port, said injection port communicating with said engine; means for supplying fuel to said pumping chamber through said inlet port; means for closing said injection port, said closing means including biasing means for keeping said injection port closed until a predetermined fuel pressure is attained in said pumping chamber; means responsive to the rotation of said engine cam shaft for periodically pressurizing the fuel in said chamber whereby the fuel in said chamber periodically flows out of said pumping chamber through said relief port; and electromechanical valve means operative to open and close said relief port at predetermined intervals in response to at least one operating parameter of said engine whereby each time said relief port is closed the fuel pressure in said pressure chamber attains the predetermined pressure level at which said injection port opens, thereby injecting fuel into said engine, and each time said relief port is open, said injection porT is closed, said electromechanical valve means is a solenoid valve having a plunger that has a first portion having an axial cross-sectional area that matches the configuration and size of said relief port and a second portion having a second axial cross-sectional area that is smaller than the relief port, said plunger mounted for axially reciprocating movement in said relief port so that in one position said first portion of said plunger closes said relief port and in a second position said second portion of said plunger opens said relief port, said solenoid core mounted so that neither end thereof terminates within said pumping chamber whereby the axial movement of said solenoid core that opens and closes said relief port is not biased by pressurized fluid within said pumping chamber.