Fuel injection pump

• US 4,402,290 A
• Filed: 11/10/1980
• Issued: 09/06/1983
• Est. Priority Date: 11/10/1979
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Hofer, Gerald
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): Moy, Magdalen
• Application Number:
  US06/205,136
• Time in Patent Office: 1,030 Days
• Field of Search: 123/359, 123/357, 123/387, 123/338, 123/333, 123/198 DB, 123/198 D, 123/458, 123/459, 123/DIG. 11, 123/332, 123/493
• US Class Current: 123/359
• CPC Class Codes: F02M 41/126 valves being mechanically or electrically adjustable sleeves slidably mounted on rotary piston
• CPC Class Codes: F02M 63/0205 for cutting-out pumps or injectors in case of abnormal operation of the engine or the injection apparatus, e.g. over-speed, break-down of fuel pumps or injectors safety devices acting on engine fuel system on lubricant pressure failure F01M1/24; for cutting-out pumps for stopping the engine
• CPC Class Codes: F02M 63/0215 by draining or closing fuel conduits

Abstract

A fuel injection pump is proposed which can be shut off by a magnetic valve if there is a danger of engine "cranking". The magnetic valve is triggered via a switch system in which one switch is actuatable with the adjusting lever of the injection pump, wherein the magnetic valve is furthermore controllable by the supply pump pressure.

Claims

1. A fuel injection pump for internal combustion engines comprising a supply pump arranged to generate an rpm-dependent fuel pressure, an adjusting lever arranged to preselect the rpm and an electrically actuatable valve positioned relative to a fuel line bore that communicates with a pump work chamber, at least one switch actuatable with the adjusting lever disposed in an electric line leading to said electrically actuatable valve, said electrically actuatable valve being controllable in accordance with the supply pump pressure whereby at an idling position of the adjusting lever and at an actual supply pump pressure which is larger than the supply pump pressure at the idling speed of the injection pump the injection of fuel is interrupted by closing said fuel line bore by means of said electrically actuatable valve.

2. A fuel injection pump as defined by claim 1, wherein at least two switches including first and second switches are disposed in parallel in an electric line and the first switch is open at a position of the adjusting lever corresponding to low rpm (idling rpm) but is closed at a position corresponding to a slightly higher rpm, while in contrast, the second switch is closed at idling rpm and is opened when the rpm and thus the fuel pressure are increasing.

3. A fuel injection pump as defined by claim 1, wherein the second switch is embodied as a fluid pressure switch, which is exposed to the fuel pressure of the supply pump.

4. A fuel injection pump as defined in claim 1, wherein an adjusting piston exposed to the supply pump pressure urges the electric valve in the closing direction and a spring and the electric actuation means urge the electric valve in the opening direction.

5. A fuel injection pump as defined by claim 1, wherein the switch which is actuatable with the adjusting lever is disposed as a travel switch between the gas pedal and the adjusting lever.

6. A fuel injection pump as defined by claim 5, wherein the switch is actuable on at an rpm corresponding to the adjusting lever position, which is lower than the rpm at which the supply pump pressure overcomes the force of the spring.

7. A fuel injection pump as defined by claim 1, wherein a supply pump driven with a pump piston is integrated in a housing of the injection pump and a large part of the pump housing is under supply pump pressure.

8. A fuel injection pump as defined by claim 1, wherein the electrically actuated valve is disposed in the fuel line between the supply pump and the pump work chamber of the fuel injection pump.

9. A fuel injection pump as defined by claim 1, wherein the electrically actuated valve is embodied as a magnetic valve.