EP0307947A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Variable discharge high pressure pump
Assignee: Denso Corp
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Filing: 1988-09-16
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Granted: —
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Expires: 2008-09-16
Abstract
Abstract A variable discharge high pressure pump (7) for pumping a fuel into a common rail (4) of a common rail type fuel injection system has a plunger (15) reciprocable in a cylinder bore and a pumping chamber (16) defined between and end face of the plunger and the inner peripheral surface of the cylinder bore. A solenoid valve (30) has a valve member (38) movable into an open position in which the valve member is moved out of engagement with an associated valve seat (37) into the pumping chamber when the solenoid valve is deenergized. When the solenoid valve is energized, the valve member is moved into a closed position in which the fuel pressure in the pumping chamber acts on the valve member to urge the same into engagement with the valve seat. The plunger (15) is of a simple cylinderical structure free from any lead formed therein.
Inventors
- 👤 Masahiko Miyaki
- 👤 Hiroyasu Daiichi Shinwa Ryo 1 Kanamori
- 👤 Yoshihisa Yamamoto
- 👤 Hiroyuki Kano
- 👤 Mikio Kumano
- 👤 Shigeyuki 113 Azanakaichi Kondoh
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 23:04
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/30; F02D41/38; F02D41/3809; F02D41/3836; F02D41/3845; F02D41/3827; F02M; F02M59/00; F02M59/20; F02M59/36; F02M59/366; F02M59/44; F02M59/46; F02M59/466; F02M63/00; F02M63/02; F02M63/0225; F02B; F02B3/00; F02B3/06; F02D2200/00; F02D2200/02; F02D2200/06; F02D2200/0602; F02D2250/00; F02D2250/31
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
254 words
A variable discharge high pressure pump (7) for use with a common rail type fuel injection system for an internal combustion engine (1), said system including a common rail (4) for accumulating a fuel pressure therein, said pump including: a cylinder (14) formed therein with at least one cylinder bore; a plunger (15) reciprocally received in said cylinder bore and having an end face cooperating with an inner peripheral surface of said cylinder bore to define a pumping chamber (16); a forward stroking movement of said plunger into said pumping chamber pressurizing a quantity of a fuel therein and discharging the thus pressurized fuel from said pumping chamber into said common rail; a solenoid valve (30) including a valve member (38) associated with said pumping chamber and defining a low pressure passage (31) adapted to be communicated with said pumping chamber; said valve member being opened outwardly from said solenoid valve into said pumping chamber when said solenoid valve is deenergized to allow said pumping chamber to be communicated with said low pressure passage, said valve member being closed when said solenoid valve is energized to interrupt the communication between said pumping chamber and said low pressure passage so that the pressurization of the fuel in said pumping chamber by said plunger is commenced; said valve member being disposed to receive from the pressurized fuel in said pumping chamber a force which urges said valve member toward the closed position; and said plunger being of a column-like structure free from any lead formed therein.
Claim 2
Dependent Claim
254 words
A variable discharge high pressure pump (7) for use with a common rail type fuel injection system for an internal combustion engine (1), said system including a common rail (4) for accumulating a fuel pressure therein, said pump including: a cylinder (14) formed therein with at least one cylinder bore; a plunger (15) reciprocally received in said cylinder bore and having an end face cooperating with an inner peripheral surface of said cylinder bore to define a pumping chamber (16); a forward stroking movement of said plunger into said pumping chamber pressurizing a quantity of a fuel therein and discharging the thus pressurized fuel from said pumping chamber into said common rail; a solenoid valve (30) including a valve member (38) associated with said pumping chamber and defining a low pressure passage (31) adapted to be communicated with said pumping chamber; said valve member being opened outwardly from said solenoid valve into said pumping chamber when said solenoid valve is deenergized to allow said pumping chamber to be communicated with said low pressure passage, said valve member being closed when said solenoid valve is energized to interrupt the communication between said pumping chamber and said low pressure passage so that the pressurization of the fuel in said pumping chamber by said plunger is commenced; said valve member being disposed to receive from the pressurized fuel in said pumping chamber a force which urges said valve member toward the closed position; and said plunger being of a column-like structure free from any lead formed therein.
Claim 3
Dependent Claim
61 words
A high pressure pump according to Claim 1, further including a cam shaft (12) adapted to be rotated a 1/2 rotation per rotation of said engine and a cam (13) for reciprocally driving the plunger, said cam being of a shape having a plurality of cam lobes so that said plunger is driven two times per rotation of said cam shaft.
Claim 4
Dependent Claim
48 words
A high pressure pump according to Claim 1, wherein, each time when the valve member (38) is closed, the solenoid valve (30) is electrically energized for a time period (T E ) longer than a response time (T O ) required for the closing of said valve member.
Claim 5
Dependent Claim
72 words
A high pressure pump according to Claim 1, wherein said cylinder has formed therein a fuel chamber (19) communicated with said low pressure passage (31) in said solenoid valve and a fuel inlet (28) provided with a restriction orifice (42b) through which the fuel is supplied into said fuel chamber from a low pressure fuel source (8, 9) said restriction orifice restricting the flow of the fuel therethrough to a predetermined rate.
Claim 6
Dependent Claim
15 words
A high pressure pump according to Claim 1, wherein said plunger (15) is substantially cylindrical.
Claim 7
Dependent Claim
40 words
A high pressure pump according to Claim 1, wherein said solenoid valve (30) is controlled by an electronic control unit (40) responsive to signals representing an engine load, an engine speed and a fuel pressure in said common rail (4).
Claim 8
Dependent Claim
160 words
A high pressure pump according to Claim 1, wherein said common rail is adapted to accumulate a high pressure of fuel to be injected into a Diesel engine (1), the solenoid valve (30) is adapted to be controlled by an electronic control unit (40) and operated in dependence on a discharge-commencement timing determined by said electronic control unit based on an operating condition of said Diesel engine and the pressure in said common rail, the control being such that, in the case where the discharge-commencement timing determined based on the engine operating condition and the common rail pressure is earlier than a discharge-commencement timing so predetermined as to assure a maximum discharge of the pump (7), said electronic control unit (40) controls the solonoid valve (30) to restrict the discharge-commencement timing based on the engine operating condition and said common rail pressure to said predetermined discharge-commencement timing until the operating condition of said Diesel engine reaches a rated operating condition.
Claim 9
Dependent Claim
88 words
A high pressure pump according to Claim 7, wherein said electronic control unit (40) determines the quantity of the fuel to be discharged by the pump such that, when the operating condition of said Diesel engine (1) is changed from the rated operating condition to a high speed operating condition, the quantity of fuel discharged per unit of time is limited so as not to raise the common rail pressure beyond a critical limit of the mechanical strength of a fuel supply circuit including said common rail (4).
Claim 10
Dependent Claim
75 words
A high pressure pump according to Claim 7, wherein said cylinder (14) has formed therein a fuel chamber (19) communicated with said low pressure passage (31) in said solenoid valve and fuel inlet (28) provided with a restriction orifice (42b) through which the fuel is supplied into said fuel chamber from a low pressure fuel source (8, 9), said restriction orifice being operative to limit the flow of the fuel therethrough to a predetermined rate.
Claim 11
Dependent Claim
66 words
A high pressure pump according to Claim 1, further including a cam (13) rotated by the engine (1) to reciprocally drive said plunger (15), said cam having a cam profile so shaped that the cam speed is low in an initial stage of a forward stroking movement of said plunger (15) and is high in a late stage of the forward stroking movement of said plunger.
References Cited (Backward Citations)
No citation records indexed.
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