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US 4,348,998 AGranted
Fuel injection pump
AssigneeRobert Bosch GmbH
InventorGerhard Stumpp
Life of this patent
Estimating the term…
Abstract
A fuel injection pump for an internal combustion engine including a low pressure sump and a sump piston, reciprocating in a cylinder, for imparting elevated pressure to the fuel for delivery to injection valves. The pressure chamber in the pump cylinder can be opened to the sump at some adjustable point of the piston stroke to limit fuel delivery. A secondary conduit between the pressure chamber and the sump includes a flow throttle that variably restricts the return flow of fuel as adjusted by fluid pressure which is regulated by a secondary fuel control mechanism. This mechanism is subject to closed-loop control via an air flow rate meter disposed in the induction tube and also acts as a limiting stop for the baffle plate of the air flow rate meter.
Claims17
A fuel injection pump for an internal combustion engine which comprises:
- a fuel sump;
- a pump cylinder;
- a steplessly variable throttle means connecting said pump cylinder to said fuel sump, for controlling the flow of fuel from said pump cylinder to said fuel sump;
- pump intake means for admitting fuel into said pump cylinder from said fuel sump;
- pump outlet means for admitting fuel into said internal combustion engine from said pump cylinder;
- a piston movably disposed in said pump cylinder for drawing fuel from said sump into said cylinder through said pump intake means and for expelling the fuel from said cylinder under pressure through said pump outlet means and said variable throttle means, wherein said variable throttle means connects said pump cylinder to said fuel sump in a manner that cannot be disturbed by operation of said piston;
- and
- a relief valve for pressure-relieving said cylinder at a variable point of the stroke of said piston, said relief valve determining the length of the piston stroke during which fuel may be supplied to the engine, and thereby determining a maximum fuel quantity supplied to the engine when said variable throttle means is completely closed;
- and
- adjustment means connected to said variable throttle means for continuous, uninterrupted adjustment of said variable throttle means during operation of the engine, said adjustment means determining the fuel quantity supplied to the engine independently of the relief valve, up to said maximum fuel quantity.
7 more elements
A fuel injection pump for an internal combustion engine which comprises:
- a fuel sump;
- a pump cylinder;
- a steplessly variable throttle means connecting said pump cylinder to said fuel sump, for controlling the flow of fuel from said pump cylinder to said fuel sump;
- pump intake means for admitting fuel into said pump cylinder from said fuel sump;
- pump outlet means for admitting fuel into said internal combustion engine from said pump cylinder;
- a piston movably disposed in said pump cylinder for drawing fuel from said sump into said cylinder through said pump intake means and for expelling the fuel from said cylinder under pressure through said pump outlet means and said variable throttle means, therein said variable throttle means connects said pump cylinder to said fuel sump in a manner that cannot be disturbed by operation of said piston;
- a relief valve for pressure-relieving said cylinder at a variable point of the stroke of said piston;
- adjustment means connected to said variable throttle means for continuous, uninterrupted adjustment of said variable throttle means during operation of the engine;
- a metering device for metering the actual fuel quantity injected by the fuel injection pump;
- and
- a comparator device for comparing the actual fuel quantity injected by the fuel injection pump with a reference value and coupled to said adjustment means so that said variable throttle means is adjusted by said adjustment means depending on the results of the comparison, whereby the difference between the actual fuel quantity injected by the fuel injection pump and the reference value is minimized.
8 more elements
A fuel injection pump for an internal combustion engine which comprises:
- a fuel sump;
- a pump cylinder;
- a steplessly variable throttle means connecting said pump cylinder to said fuel sump, for controlling the flow of fuel from said pump cylinder to said fuel sump;
- pump intake means for admitting fuel into said pump cylinder from said fuel sump;
- pump outlet means for admitting fuel into said internal combustion engine from said pump cylinder;
- a piston movably disposed in said pump cylinder for drawing fuel from said sump into said cylinder through said pump intake means and for expelling the fuel from said cylinder under pressure through said pump outlet means and said variable throttle means, therein said variable throttle means connects said pump cylinder to said fuel sump in a manner that cannot be disturbed by operation of said piston;
- a relief valve for pressure-relieving said cylinder at a variable point of the stroke of said piston;
- adjustment means connected to said variable throttle means for continuous, uninterrupted adjustment of said variable throttle means during operation of the engine;
- a fuel reservoir in fluid communication with an inlet of said fuel sump;
- flow control means connected upstream of said inlet of said fuel sump and defining a variable metering orifice which determines a reference fuel quantity intended to flow to the sump of the fuel injection pump;
- comparator means, coupled to said adjustment means, for comparing the actual fuel quantity flowing to the sump of said fuel injection pump with said reference fuel quantity whereby said variable throttle means is adjusted by said adjustment means depending on the results of the comparison to minimize the difference between the actual fuel quantity flowing to the sump of the fuel injection pump and said reference fuel quantity;
- and
- air flow responsive means, coupled to said flow control means to vary the flow therethrough.
10 more elements
Dependencies are inferred from the claim text.