US3926163A - Method and device for stopping an internal combustion engine with fuel injection in case of overspeed - Google Patents

Abstract

Method and device for stopping in case of overspeed an internal combustion engine having fuel injection pumps of the constant stroke, reciprocating piston type, in which a pad defines in the pump body two separate closed chambers, wherein a compressed inert gas is fed in the second chamber for separating the pump piston from its tappet and thereby stopping the injection pump.

Description

United States Patent [1 1 Bastenhof 1 Dec. 16, 1975 METHOD AND DEVICE FOR STOPPING AN INTERNAL COMBUSTION ENGINE WITH FUEL INJECTION IN CASE OF OVERSPEED [75] Inventor: Dirk Bastenhof, Eaubonne, France [73] Assignee: Societe dEtudes de Machines Thermiques, Saint Denis, France [22] Filed: May 28, 1974 [21] Appl. No.: 473,940

[30] Foreign Application Priority Data June 26, 1973 France 73.23380 [52] US. CL. 123/139 AZ; 123/198 D; 123/198 DB [51] Int. Cl. F02B 77/00 [58] Field of Search... 123/139 AZ, 198 D, 198 DB;

[56] References Cited UNITED STATES PATENTS 2,638,053 5/1953 Nicolls l23/l39.13

Alfieri 92/129 Stolworthy 123/198 DB Primary E.raminer-Wendell E. Burns Assistant E.\'aminerPaul Devinsky Attorney, Agent, or Firm-Kenyon & Kenyon Reilly Carr & Chapin 5 7 ABSTRACT Method and device for stopping in case of overspeed an internal combustion engine having fuel injection pumps of the constant stroke, reciprocating piston type, in which a pad defines in the pump body two separate closed chambers, wherein a compressed inert gasis fed in the second chamber for separating the pump piston from its tappet and thereby stopping the injection pump.

11 Claims, 1 Drawing Figure US. Patent Dec. 16, 1975 METHOD AND DEVICE FOR STOPPING AN INTERNAL COMBUSTION ENGINE WITH FUEL INJECTION IN CASE OF OVERSPEED The present invention relates essentially to a method of stopping an internal combustion engine with fuel injection, including fuel-injection pumps of the constant stroke, reciprocating piston type, in case of overspeed and attendant danger of racing.

The invention relates also to an emergency stop de vice for carrying out this method as well as to the various applications and uses thereof and to the systems, assemblies, apparatus, vehicles, engines, plants, equipments and installations fitted with such a device (see, e.g. French Pat. No. 2,120,400, corresponding to US. Pat. No. 3,750,640).

There are already known devices in which, in case of overspeed ofan internal combustion engine with fuel injection, an overspeed-sensitive or overspeed-responsive triggering or tripping member or like release device opens a pressure-fluid supply valve for feeding one or several power cylinder actuators or like servomotors the pistons of which will act upon the control racks operating the injection pumps so as to stop or discontinue the fuel injection provided by all pumps. A significant disadvantage of these devices is that they cannot work upon an accidental blockin'g or jamming of the rack or of the mechanical transmission, drive or gear connected between the power cylinders and the rack.

There are also known devices for stopping the injection pumps by means of hydraulic ram actuators which are fitted each one on an injection pump and which are supplied in case of overspeed of the engine with a fluid under pressure enabling to displace the piston of each ram actuator and to convey the motion of the piston of the ram actuator to the piston of the injection pump by means of a lever for separating said piston from its tappet, push-rod or like lifter and from its operating cam. The disadvantage of such a device is its relative complexity and its high cost price.

The invention therefore provides a process and a particularly simple device for stopping the fuel injection pumps in case of overspeed of the internal combustion engine, which are quite reliable and the cost price of which is relatively low.

According to the invention, the method of stopping in case of overspeed an internal combustion engine including fuel injection pumps of the constant strokereciprocating piston type and in which a bolster or pad Le, a hollow cylinder closed at one end sliding within the pump body and interposed between the piston and its operating tappet, push-rod or lifter defines within the pump body two separated closed chambers the first one of which contains the piston and the second or other one contains the tappet, is characterized in that it consists, in case of overspeed of the engine, in feeding a compressed gaseous fluid into said second chamber with a pressure high enough for disengaging and separating as known per se said bolster or pad hence said piston from said tappet and thereby stopping the corresponding injection pump.

Thus according to the invention a compressed fluid such as air or preferably an inert gas such as nitrogen or carbon dioxide is directly admitted inside of the pump body so as to cause the pressure of this gas to act upon the pad or bolster interposed between the pump piston and its operating tappet for separating the piston from the tappet and thereby cutting off or discontinuing the fuel injection by the pump involved.

The device for stopping, in case of overspeed, an in ternal combustion engine with fuel injection including injection pumps of the constant stroke-reciprocating piston type, in which the piston is separated from its operating tappet by a sliding pad or member defining within the pump body or casing a pair of separated closed chambers the first one of which houses the piston and the second one of which contains the tappet and is provided with a fuel drain or leakage recovering or collecting duct, is characterized according to the invention in that it comprises means enabling feeding into said second chamber a compressed fluid in case of overspeed of the engine with a pressure high enough for disengaging and separating in a manner known per se said pad hence said piston from said actuating tappet and thereby stopping each fuel injection pump.

The device according to the invention is therefore considerably simplified with respect to the known prior state of the art as it does no longer comprise power cylinders or ram actuators adapted to act upon the racks or upon a lever for separating the pump piston from its actuating tappet.

According to another characterizing feature of the invention the compressed gaseous fluid feed means comprise a compressed gaseous fluid source or supply connected by an overspeed-sensitive triggering device or like overspeed-responsive release contrivance to said fuel leakage recovering duct within said second chamber.

Thus according to the invention the fuel leakage recovering duct is used to feed the compressed fluid into the inside of the pump body or casing.

The invention will be better understood and further objects, characterizing features, details and advantages thereof will appear more clearly as the following explanatory description proceeds with reference to the accompanying diagrammatic drawing given by way of non-limiting example only illustrating a presently preferred form of embodiment of the invention and wherein the single FIGURE shows a partial longitudinal sectional view of an injection pump used in the emergency stop device according to the invention.

The method and the device for stoppage according to the invention are therefore intended for use on internal combustion engines with fuel injection including fuel injection pumps 1 having a constant-stroke reciprocating piston 12. This piston 12 is driven according to a translatory motion by means of a tappet or like lifter or pusher member 3 resting through a follower or like roller 4 on an operating cam 5. A pad or member 6 which is a hollow cylinder closed at one end is slidably mounted within the body or casing 7 of the pump 1 and is interposed between the piston 12 and its operating tappet 3. This pad or member thereby defines within the body or casing of the pump 1 a pair of separated closed chambers 8 and 9 the first one of which contains the piston 12 and the second one of which contains the tappet 3. This second chamber is provided at its bottom portion with a fuel leakage recovering duct 10.

The piston 12 is also operatively or drivingly rotated by means of a gear or pinion 2 through a toothed rack 11 which is diagrammatically shown in cross-section and which enables adjustment of flow rate of the injected fuel through rotation of the piston 12 in a manner known per se.

It may happenthat the toothed rack. 11 is blocked or jammed in a position corresponding to the maximum flow rate of injected fuel, for various grounds, for instance in view of scoring or seizing or in the presence of dirt. In such a case the engine exhibits a tendency to race and it becomes necessary to stop it forthwith by discontinuing the fuel injection. For this purpose the invention contemplated to feed a compressed gaseous, preferably inert fluid such as nitrogen or carbon dioxide, into the second chamber 9 containing the tappet, this compressed gas having a pressure high enough to overcome the opposing biasing force of the piston drawback or return spring 13 and thereby to fully disengage and separate the pad or member 6 of the piston.

12 from the drive tappet 3. There is no longer any fuel injection and the engine stops.

The admission of compressed gaseous fluid into the chamber 9 is carried out very easily by means of the fuel leakage recovering duct or pipe 10 which is then connected to a source or supply of compressed air operated by an engine overspeed-sensitive triggering device 16.

The upper or top chamber 8 containing the piston 12 is advantageously provided with a means 17 for venting same to the outer atmosphere, such for instance as a calibrated safety valve, a check valve or a simple breather or snifting-valve so as to avoid the building up within this chamber 8 of too high a pressure caused by the compressed gaseous fluid leakages from the chamber 9 to this chamber 8. Thereby is also avoided the clogging or fouling of the toothed rack 11 by dirt'or fuel leaks which would climb up towards the toothed rack under the action of this pressure within the chamber 8.

The device provided by the invention is therefore considerably simplified with respect to the known prior art and its operation is much more reliable.

The pad or member 6 used may thus be provided without communication holes or passageways between the chambers 8 and 9 as depicted in the drawings or it may be formed with thoroughfare holes extending therethrough and providing a communication between the chambers 8 and 9, these holes being provided with valves allowing passage of a compressed gaseous fluid from chamber 8 to chamber 9 only. Thus the invention is very easily applicable to previously known injection pumps.

It should be understood that the invention is not at all limited to the form of embodiment described and shown which has been given by way of example only. In particular it comprises all the means constituting technical equivalents of the means described as well as their combinations if same are carried out according to the gist and used within the scope of the appended claims.

What is claimed is:

1. A method of stoppingan internal combustion engine, in case of overspeed, including fuel injection pumps of the constant-stroke, reciprocating piston type, each of said pumps comprising a pump body, having a pump cylinder and an intermediate cylinder adjacent to and in alignment with the pump cylinder, a pump piston in the pump cylinder, a drive tappet for driving said piston, an intermediate drive piston disposed in the intermediate cylinder between said pump piston and said drive tappet and being combined there with, said intermediate drive piston defining within said body a pair of separated closed chambers, a first one of which contains said pump piston and a second one of which contains said tappet, said method comprising a source of pressurized gaseous fluid sensing an engine overspeed condition, and feeding in response to the sensing of overspeed of the engine pressurized gaseous fluid from the source into the second chamber, the pressurized gaseous fluid having a pressure high enough when fed into the second chamber to urge the intermediate drive piston toward the first chamber and to disengage and separate the intermediate drive piston and thereby the pump piston from being driven by the drive tappet and to thereby stop the corresponding injection pump.

2. A method according to claim 1, wherein said gaseous fluid is an inert gas.

3. A method according to claim 1, wherein said gaseous fluid is air.

4. A device for stopping an internal combustion engine in case of overspeed including fuel injection pumps of the constant-stroke, reciprocating piston type, each of said pumps comprising a pump body, a piston, a drive tappet for driving the piston, a hollow cylinder closed at one end and slidably mounted within said pump body between said piston and said tappet and defining within said pump body a pair of separated closed chambers, a first one of which contains said piston and the second one of which contains said tappet, said device comprising a source of pressurized gaseous fluid, and means for providing a communication between said source and said second chamber for feeding said pressurized gaseous fluid into said second chamber, said gaseous fluid having a pressure high enough for disengaging and separating said hollow cylinder and thereby said piston from said drive tappet to thereby stop said injection pump.

5. A device according to claim 4, wherein said second chamber has a fuel lead recovering duct extending from the interior to the exterior of the second chamber, valve means for connecting the duct to the source of pressurized gaseous fluid and an overspeed-sensitive triggering device connected to the valve means for releasing pressurized gaseous fluid into the duct in response to an overspeed condition.

6. A device according to claim 4, wherein said gaseous fluid is an inert gas.

7. A device according to claim 4, wherein said gaseous fluid is air.

8. A device according to claim 4, wherein said first chamber includes venting means for allowing the exhaust of pressurized gaseous fluid leaks flowing from said second chamber into said first chamber.

9. A device according to claim 8, wherein said venting means is a check valve.

10. A device according to claim 8, wherein the venting means is a snifting-valve.

1 l. A device according to claim 8, wherein said injection pump comprises a control toothed rack, and said venting means comprises grooves formed in said

Claims (11)

1. A method of stopping an internal combustion engine, in case of overspeed, including fuel injection pumps of the constant-stroke, reciprocating piston type, each of said pumps comprising a pump body, having a pump cylinder and an intermediate cylinder adjacent to and in alignment with the pump cylinder, a pump piston in the pump cylinder, a drive tappet for driving said piston, an intermediate drive piston disposed in the intermediate cylinder between said pump piston and said drive tappet and being combined therewith, said intermediate drive piston defining within said body a pair of separated closed chambers, a first one of which contains said pump piston and a second one of which contains said tappet, said method comprising a source of pressurized gaseous fluid sensing an engine overspeed condition, and feeding in response to the sensing of overspeed of the engine pressurized gaseous fluid from the source into the second chamber, the pressurized gaseous fluid having a pressure high enough when fed into the second chamber to urge the intermediate drive piston toward the first chamber and to disengage and separate the intermediate drive piston and thereby the pump piston from being driven by the drive tappet and to thereby stop the corresponding injection pump.

2. A method according to claim 1, wherein said gaseous fluid is an inert gas.

3. A method according to claim 1, wherein said gaseous fluid is air.

4. A device for stopping an internal combustion enGine in case of overspeed including fuel injection pumps of the constantstroke, reciprocating piston type, each of said pumps comprising a pump body, a piston, a drive tappet for driving the piston, a hollow cylinder closed at one end and slidably mounted within said pump body between said piston and said tappet and defining within said pump body a pair of separated closed chambers, a first one of which contains said piston and the second one of which contains said tappet, said device comprising a source of pressurized gaseous fluid, and means for providing a communication between said source and said second chamber for feeding said pressurized gaseous fluid into said second chamber, said gaseous fluid having a pressure high enough for disengaging and separating said hollow cylinder and thereby said piston from said drive tappet to thereby stop said injection pump.

5. A device according to claim 4, wherein said second chamber has a fuel lead recovering duct extending from the interior to the exterior of the second chamber, valve means for connecting the duct to the source of pressurized gaseous fluid and an overspeed-sensitive triggering device connected to the valve means for releasing pressurized gaseous fluid into the duct in response to an overspeed condition.

6. A device according to claim 4, wherein said gaseous fluid is an inert gas.

7. A device according to claim 4, wherein said gaseous fluid is air.

8. A device according to claim 4, wherein said first chamber includes venting means for allowing the exhaust of pressurized gaseous fluid leaks flowing from said second chamber into said first chamber.

9. A device according to claim 8, wherein said venting means is a check valve.

10. A device according to claim 8, wherein the venting means is a snifting-valve.

11. A device according to claim 8, wherein said injection pump comprises a control toothed rack, and said venting means comprises grooves formed in said toothed rack.

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