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US 5,220,894 AGranted
Fuel injection pump for internal combustion engines
AssigneeRobert Bosch GmbH
InventorMax Straubel
Life of this patent
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AssigneeRobert Bosch GmbH
InventorMax Straubel
Estimating the term…
A fuel injection pump for internal combustion engines for controlling the fuel quantity with an electric closed-loop control device, which controls an electric positioner, which in turn actuates an element that determines the fuel injection quantity per pump piston supply stroke. The supply of fuel to the pump work chamber is effected via a fuel supply line, in which an adjustable throttle is disposed. The throttle is actuated in accordance with the position of a gas pedal, but it controls an increasingly larger through cross section of the fuel supply line than would correspond to the fuel metering by the closed-loop control device. A minimum through cross section is defined by a fixed throttle. With this apparatus, emergency operation if the electric control system for the fuel injection quantity fails can be attained, without the apparatus for emergency operation interfering with fuel metering by the closed-loop control device. In particular, the fixed throttle prevents racing of the engine counter to the intentions of the driver in the event that the closed-loop control system fails.
A fuel injection pump for internal combustion engines, having a housing, a cylinder (2) in said housing, a pump work chamber (4) defined by a pump piston (3) driven to reciprocate in said cylinder, a fuel supply line (8) that is made to communicate with the pump work chamber (4), a throttle (40, 140, 240, 50, 57) disposed in said supply line (8) that is arbitrarily adjustable in accordance with an intended torque output by the engine, via which throttle the pump work chamber is made to communicate with a fuel source (9) at low pressure, upon an intake stroke of the pump piston, a relief conduit (20) leading away from the pump work chamber (4), by which the fuel injection quantity communicates with a low pressure fuel source (9), by means of a control device (25, 18) controllable by an electric closed-loop control device (23) as a function of operating parameters, wherein at least a position of a gas pedal (32) is detected by the electric closed-loop control device (23) for controlling the fuel injection quantity, the adjustable throttle (40-, 140, 240, 50, 57) is movable into a position in which a minimum, constant flow cross section between the fuel source (9) and the pump work chamber (4) is maintained, and in other positions, a larger cross section of the fuel supply line (8) is always opened more than would be necessary to carry the fuel injection quantity, controlled by the electric closed-loop control device, into the pump work chamber (4) in the intake stroke of the pump piston.
Dependencies are inferred from the claim text.