Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1988-10-13
1990-09-18
Miller, Carl Stuart
Internal-combustion engines
Charge forming device
Fuel injection system
123198DB, F02M 3900
Patent
active
049570846
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a fuel injection apparatus for internal combustion engines, particularly for diesel engines.
In such fuel injection apparatus, the cut-off device serves to terminate the fuel injection as suddenly as possible during the occurrence of disturbances or errors. For this purpose, it is necessary not only to stop the delivery output of the delivery pump to the suction chamber of the fuel injection pump, but also to prevent the continued delivery of fuel from the suction chamber to the injection nozzles. The latter is no longer the case when the suction chamber pressure drops below 0.2 bar absolute, since the pump element of the fuel injection pump is then no longer sufficiently filled with fuel.
In a known fuel injection apparatus (DE-A-21 45 983), the cut-off device comprises a shut-off valve, which is constructed as a disk valve, and a suction pump which are combined to form a constructional unit. The suction pump comprises a plunger displaceable in a storage space and a pressure spring which acts upon the plunger. In normal operation, a mechanical locking device holds the plunger in a sliding out position when the pressure spring is tensioned, in which sliding out position the storage volume of the storage space is virtually zero. In this position, the disk valve is held by the plunger in the open position against the force of a valve closing spring via a valve tappet When the disk valve is open, the fuel delivered by the delivery pump arrives in the space defined by the plunger, in which the plunger pressure spring is arranged and flows out into the suction chamber When a cut-off is effected, the locking device is released The plunger is displaced by the plunger pressure spring and releases the storage space. A vacuum pressure accordingly arises in the line between the cut-off device and the suction chamber which prevents additional fuel from reaching the suction chamber of the injection pump. The plunger, sliding back in the storage space, also releases the disk valve, which moves into its closing position under the action of its valve closing spring. The delivery pump is blocked by the suction chamber and delivers back into the fuel tank via an overflow valve.
SUMMARY OF THE INVENTION
The object of the invention is to provide a fast-acting cut-off device with commercially available structural component parts, such as spring-loaded accumulators, simple hydraulic valves and magnetic valve, which fast-acting switch-off device is constructed in a simple manner in terms of design, and is inexpensive to manufacture. The object of the invention is achieved by providing a cut-off device which includes an inlet valve arranged upstream of the suction chamber and a spring-loaded accumulator whose storage chamber is connected with the output of the delivery pump and whose spring chamber is connected with the suction chamber of the fuel injection pump. An electromagnetically actuated control valve located in a by-pass line connecting the output of the delivery pump with the tank, blocks the by-pass line in normal operation and opens it upon actuation of the cut-off device. The suction chamber pressure is adjusted to a defined pressure, e.g. 1 bar overpressure, by an overflow valve. The delivery pressure, which exceeds the suction chamber pressure, in this case, e.g. 2 bar overpressure, loads the spring-loaded accumulator so that its spring chamber has the lowest possible volume. When cut-off is effected, the by-pass is opened, so that the overpressure generated by the delivery pressure in the storage chamber of the spring-loaded accumulator collapses. The spring-loaded accumulator is unloaded and the increasing spring chamber volume causes a reduction of pressure in the suction chamber to less than 0.2 bar absolute in this instance, so that the delivery of fuel to the injection nozzles is interrupted suddenly. The internal combustion engine receives no more fuel and immediately turns off.
By the electromagnetic control valve being a two-way valve, the greatest va
REFERENCES:
patent: 2986881 (1961-06-01), Moore
patent: 3568646 (1971-03-01), Wehde
patent: 4296718 (1981-10-01), Baugh
patent: 4319550 (1982-03-01), Ishii
patent: 4361121 (1982-11-01), Clemens et al.
patent: 4381750 (1983-05-01), Funada
patent: 4485789 (1984-12-01), Walter
patent: 4530329 (1985-07-01), Maisch
patent: 4565170 (1986-01-01), Grieshaber et al.
patent: 4627403 (1986-12-01), Matsumura
patent: 4811710 (1989-03-01), Schmitt
Kramer Manfred
Sitter Erhard
Miller Carl Stuart
Robert & Bosch GmbH
Striker Michael J.
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