WO1982004287A1

WO1982004287A1 - Rotary controlled fuel injection apparatus with automatic shut-off

Info

Publication number: WO1982004287A1
Application number: PCT/US1981/000697
Authority: WO
Inventors: Alexander Goloff; George B Grim
Original assignee: Alexander Goloff; George B Grim
Priority date: 1981-05-26
Filing date: 1981-05-26
Publication date: 1982-12-09

Abstract

Fuel injection apparatus employing continuously rotating rotors function to control the timing and duration of fuel injection into a cylinder of a diesel engine. The advent of sophisticated electronic drive means for continuously rotating the rotors has given rise to the need for shutting-off fuel injection in the event of a power failure. This invention is directed to overcoming the above problem by providing a shut-off system (54) for automatically venting a pumping cavity (25) of a high-pressure fuel pump (22) to prevent communication of pressurized fuel to a nozzle (13) in response to deactivation of a drive (40) that continuously rotates a control rotor (29) during normal engine operation.

Description

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Description

Rotary Controlled Fuel Injection Apparatus With Automatic Shut-Off

Technical Field

This invention relates generally to a fuel injection apparatus for internal combustion engines and more particularly to a shut-off system for automatically venting a high-pressure pump to prevent communication of pressurized fuel to a nozzle in response to deactivation of a drive system for continuously rotating a fuel injection • control rotor.

Background Art

Applicant has developed a fuel injection system wherein a main fuel is communicated to a nozzle from a high-pressure fuel pump under control of a pair of continuously rotating rotors. One of the rotors starts fuel injection, whereas the other rotor stops injection by venting. a pumping cavity of the pump. The advent of electronic drive means for continuously rotating the rotors has give rise to the need for a safety shut-off system that will prevent fuel injection in the event the drive system is deactivated.

In particular, the high-pressure fuel pump may include a plunger that is reciprocated -2-

through its suction- and compression strokes by a camshaft driven by the main drive shaft of the engine. In the event of an electrical power failure, the fuel injection control rotors might stop in positions wherein the fuel pump will continue to deliver pressurized fuel to the nozzle indiscriminately in response to continued rotation of the camshaft.

The present invention is directed to overcoming one or more of the above—described problems.

Disclosure of Invention

In one aspect of the present invention, a fuel injection system having a source of fuel, nozzle means for ejecting fuel therefrom, pump means for communicating pressurized fuel to the nozzle means, rotor means for controlling the pressurization of fuel in the pump means to start and stop ejection of fuel in response to continuous rotation of the rotor means, and drive means for continuously rotating the rotor means, further includes the improvement comprising shut- off means for actuating the rotor means to vent the pump means to prevent communication of pressurized fuel to the nozzle means.

The improved fuel injection system embodying this invention will thus provide a fail¬ safe system which will stop the engine by terminating indiscriminate fuel injection -3-

thereto in the event electronic controls associated with the rotor means, for example, become deactivated due to a power failure. The shut-off means can also be adapted for manual 5 operation.

Brief Description of the Drawings

Other advantages and objects of this invention will become apparent from the following 10 description and accompanying drawings wherein:

Figure 1 schematically illustrates a fuel injection system embodying a shut-off system of this invention therein, and

Figure 2 schematically illustrates an 15 electronic drive means for continuously rotating control rotors employed in the system.

Best Mode of Carrying Out the Invention

Figure 1 schematically illustrates a

20 fuel injection system 10 including a fuel injection apparatus 11 for selectively controlling the ejection of pilot and main fuel through injectors or nozzles 12 and 13, respectively. The nozzles are of the standard type, incorporating

25 pressure responsive check valves therein (not shown) that will open whe subjected to relatively high fuel pressures in the range of 20,685 kPa, for example. System 10 further includes

30 a first reservoir 14, containing a source * -4-

of pilot fuel 15 which may exhibit a relatively high cetane rating for quick ignition.

The pilot fuel is communicated to the fuel injection apparatus via a standard transfer 5 pump 16 and a conduit 17. A second reservoir 18 contains a source of main fuel 19 which may have a lower cetane rating than the pilot fuel and is communicated to fuel injection apparatus 11 via a standard transfer pump 20 and a conduit 21.

10 Conduit 21 communicates with a high-pressure main fuel pump 22 having a plunger 23 reciprocally mounted therein to effect the well-known suction and compression strokes of operation.

As is well known in the art, plunger 23

15 is continuously reciprocated during engine operation by a lobe 24* of an engine-driven camshaft 24 to periodically communicate pressurized fuel from a pumping cavity 25 to main fuel nozzle 13, via a conduit 26. Pumping cavity

20 25 further communicates with a first rotor means 27, via a conduit 28. First rotor means 27 functions to control the pressurization of fuel in pumping cavity 25 to both start and stop ejection of main fuel through nozzle 13 in response to

25. continuous rotation of rotor means 27.

Rotor means 27 comprises a first rotor 29, mounted in a stationary housing 30, having a circumferential groove 31 formed thereon and interrupted by a blocking shoulder 32. In

30 the illustrated open or non-blocking position

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of shoulder 32, pumping cavity 25 is free to communicate with drain 18 via conduit 28, an inlet 33, groove 31, and an outlet 34.

A conduit 35 connects conduit 28 with a rotor 36 that is rotatably mounted in a housing 37 which may form part of housing 30. Rotor 36 has a circumferential groove 38 formed thereon that is interrupted by a blocking shoulder 39. In the illustrated open or non-blocking position of shoulder 39, conduit 28 is also free to communicate with reservoir 18, through conduit 35 and groove 38.

The rotation of camshaft 24 to reciprocate plunger 23, as well as the rotation of rotors 29 and 36, are properly sequenced in timed relationship to effect main fuel injection upon upward movement of plunger 23 during its compression stroke while simultaneously blocking inlet 33 by blocking shoulder 32 and the inlet to rotor 36 by blocking shoulder 39. The relatively high fuel pressure in pumping cavity 25 is thereafter relieved or vented to stop the injection of main fuel through nozzle 13 by positioning blocking shoulder 39 in its non- blocking position.

Referring to Figures 1 and 2, an electronic means 40 may be utilized to continuously rotate rotors 29 and 36 during engine operation. Electronic means 40 may -6-

comprise a -standard electric drive motor or an electronic control system of the type shown in Figure 2. Alternatively, the rotors may be continuously rotated by a suitable power-takeoff from the crankshaft of the engine (not shown), as is also well known in the arts relating hereto.

Referring to Figure 2, .electronic means 40 may comprise a control transmitter 41 and a control transformer and servo 42. Control transmitter 41 may be suitably driven by camshaft 24 (Figure 1) at one-half engine speed (for a four¬ cycle engine), and through well-known buffering networks adapted to directly drive control transformer and servo 42 to rotate a respective rotor 29 or 36. By selectively adjusting the position of a stator 43 of control transmitter 41, the starting of injection by rotor 29 in cooperation with rotor 36 can be closely controlled. This adjustment is accomplished by. adjusting the timed position of blocking shoulder 32 relative to the rotational position of camshaft 24 to precisely set the time when blocking . shoulder 32 begins to block inlet 33 to thus control the starting of fuel injection by pump 22. Electronic means 40, associated with rotor 36, functions in a similar manner to have its control transmitter 41 also driven by camshaft 24 to directly drive control transformer and servo 42 for rotating the rotor. Adjustment of stator 43 will control the stopping of fuel

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injection by pump 22 in that the timed position of the trailing edge of blocking shoulder 39 relative to blocking shoulder 32 will precisely set the timing wherein the blocking shoulders 32 and 39 are relatively positioned to vent pumping cavity 25 to reservoir 18 in the manner described above. The off-the-shelf type of electronic equipment utilized for supplying the above-described functions of electronic means 40 is readily available from commercial suppliers such as

Aeroflex and the Singer Instrument Company, both of the United States of America. Since the means for continuously rotating rotors 29 and 36 does not, per se, form part of this invention, further discussion is deemed unnecessary for a full understanding and practicing of this invention.

Referring once again to Figure 1, ejection of pilot fuel 15 from pilot nozzle 12 is controlled by a second rotor means 44 which is common to first rotor 29 for simultaneous rotation thereof. Second rotor means 44 includes a circumferential groove 45 formed on rotor 29 and interrupted by a blocking shoulder 46. Injection of pilot fuel 15 is effected by a high-pressure , pilot fuel pump 47 having a plunger 48 reciprocally mounted therein and a pumping cavity 49.

During such pilot injection through nozzle 12, blocking shoulder 46 will cover an inlet 50 which is connected between second rotor means 44 and pumping cavity 49 by a conduit 51. In timed relationship therewith, rotation of camshaft 24, having a second cam lobe 24^{■ ■} secured thereon for engagement with plunger 48, will effect the compression stroke of pump 47 for pilot injection purposes. Such pilot injection is terminated when blocking shoulder 46 further rotates to uncover inlet 50 to vent pumping cavity 49 to reservoir 14- via conduit 51, inlet 50, groove 45 , an outlet 52, and a drain conduit 53.

It should be noted that standard delivery or check valves are preferably associated with the outlets from pumps 22 and 47 to prevent drainage of conduits connected to the respective nozzles. As further shown in Figure 1, this invention is directed to a shut-off means 54 for automatically venting pumping cavities of each pump means 22 and 47 to their respective reservoirs to prevent communication of pressurized pilot and main fuel to nozzles 12 and 13 in response to deactivation of drive means 40. As will be more fully understood hereinafter, shut- off means 54 is equally applicable to fuel control systems wherein the pilot fuel injection subsystem is not required, i.e., the engine operates with only main fuel injection. In either application, the engine will stop running in the event of an electrical power failure since no fuel will be communicated to the combustion chambers thereof.

^"BURE Shut-off means 54 comprises a solenoid 55 that is normally energized by an electrical power source 56, common to both electronic drive means 40 and the solenoid, to move rotor 29 into 5 its operational position illustrated in Figure 1. In particular, a reciprocal plunger 57 of the solenoid is connected to rotor 29 by a standard thrust bearing assembly 58 to permit the rotor to rotate relative to the plunger and to counteract 10 thrust forces therebetween. A shaft 59 is secured to an upper end of rotor 29 and is attached to a rotary output drive shaft 60 of electronic drive means 40 by a spline connection 61.

Spline connection 61 mechanically 15 interconnects rotor 29 and shaft 60 to permit the shaft to rotate the rotor during engine operation and to further permit shaft 59 and the rotor to be biased downwardly from their positions shown in Figure 1 under the force of a biasing means 62, 20 shown in the form of a compression coil spring, when electrical power source 56 becomes deactivated. As shown, the spring is mounted on shaft 59 and is normally compressed between rotor 29 and shaft 60, under the upward force imposed on 25. the rotor by activated solenoid 55.

In the event of a power failure whereby electrical power source 56 is deactivated, electronic drive means 40 and solenoid 55 will also become deactivated. Biasing means 62 will 30 then expand to move rotor 29 downwardly to -10-

its shut-off position 29' (solenoid plunger 57 being reciprocally mounted in solenoid 55 to accomodate such movement) . A first circumferential groove 63 will thus communicate pumping cavity 25 of main fuel pump 22 with reservoir 18 and a second circumferential groove 64, also formed on rotor 29, will communicate pumping cavity 49 of pilot injection pump 47 with reservoir 14. In applications wherein rotor 36 is connected directly to outlet 34, downstream of rotor 29, a similar shut-off means 54 would be connected to rotor 36 and operate in unison with the illustrated shut-off means connected to rotor 29. Since the pumping cavities of the respective pumps are now vented, adequate pressure cannot be built-up in the pumping cavities for fuel injection purposes even though camshaft 24 continues to rotate. If so desired, a low- pressure source 65' of engine lubricating oil or fuel can be connected to a spring chamber 66, via a conduit 67, to lubricate spline connection 61 to prevent fretting thereof.

Industrial Applicability

Fuel injection system 10 is particularly adapted for use in diesel engines having in-line fuel pumps 22 and 47, unit injectors, and other types of fuel injection pumps of the plunger type wherein at least one such pump is used

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per engine cylinder. Furthermore, the fuel injection system is particularly adapted for use with rotary control apparatus 11 which controls both the timing and quantity of fuel injection. Although fuel injection system 10 is shown to include second rotor means 44 for controlling the injection of a pilot fuel in a pilot fuel injection sub-system, it should be understood that the pilot fuel injection system could be eliminated for a particular engine application when only main fuel injection is desired. The pilot fuel injection system is useful in applications wherein it is desired to employ an easily ignitable or high-cetane fuel for pilot injection and a less easily ignitable or low- cetane fuel for main injection. The staged, pilot- main injection sequence will, of course, function to conserve petroleum-based fuels, and facilitates the use of other fuels, such as syncrudes, shale oil, methanol, other types of alchohols, mixtures of low-cetane fuels, etc.

In operation of fuel injection system 10, pilot fuel injection is initiated by filling pumping cavity 49 of pump 47 during the suction stroke thereof by means of transfer pump 16 and conduit 17. The timed rotation of camshaft 24 to begin the compression stroke of pump 47 will close- off conduit 17 and thereafter pressurize the fuel in the pumping cavity in the range of 20,685 kPa, for example, to effect pilot fuel injection

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through pilot nozzle 12. Simultaneously therewith, blocking shoulder 46 will block inlet 50 to permit such injection to occur. Continued rotation of blocking shoulder 46 of rotor 29 will uncover inlet 50 to vent pumping cavity 49 to reservoir 14 via conduit 51, inlet 50, groove 45, outlet 52, and conduit 53 to stop pilot fuel injection.

Such pilot fuel injection is immediately followed by the main fuel injection cycle which is initiated by filling pumping cavity 25 of main fuel pump 22 during the suction stroke thereof, via transfer pump 20 and conduit 21. When rotors 29 and 36 rotate to positions wherein the blocking shoulders thereof isolate conduit 28, pumping cavity 25 will also be isolated to permit main fuel injection through main nozzle 13. In -particular, during the compression- stroke of pump 22, camshaft 24 will rotate to move plunger 23 ^" upwardly to first close off the outlet from conduit 21 and then compress the fuel in isolated pumping cavity 25 in a pressure range of 20,685 kPa,. for example, to effect the main fuel injection. Main fuel injection is stopped when blocking shoulder 39 of rotor 36 is rotated to its open position to vent pumping cavity 25.

In the event of an electrical power failure in electrical power source 56, electronic drive means 40 and solenoid 55 will become deactivated to permit expansion of biasing means 62 to move rotor 29 downwardly to its shut-off position 29'. Circumferential grooves 63 and 64 will thus place pumping cavity 25 in communication with reservoir 18 and pumping cavity 49 in communication with reservoir 14, respectively, to stop the engine. Even though camshaft 24 may continue to rotate, the pumping cavities will be continuously vented to prevent the opening of the standard pressure-responsive check valves interconnected between the pumps and nozzles 12 and 13, as shown in Figure 1.

It should be understood that rotors 29 and 36 could be driven mechanically by a standard power take-off from the crankshaft of the engine (not shown) rather than electronically. Alsp, solenoid 55 could b.e deactivated manually by a standard switching arrangement. In addition, solenoid 55 could be replaced by a standard mechanical linkage arrangement for selectively releasing plunger 57 at the will of the operator to permit biasing means 62 to move rotor 29 downwardly to its 29' position, stopping the engine. Other aspects, objects, and advantages of this invention can be obtained from a study of the drawings, the disclosure, and the appended claims.

Claims

-14-Claims

1. In a fuel injection system (10) having a source of fuel (18), nozzle means (13) for ejecting fuel therefrom, pump means (22) for communicating pressurized fuel to said nozzle means (13), rotary means (27) for controlling the pressurization of fuel in said pump means (22) to start and stop ejection of fuel through said nozzle means (13) in response to continuous rotation of said rotor means (27), and drive means (40) for continuously rotating said rotor means (27), the improvement comprising: shut-off means (54) for actuating said rotor means (27) to vent said pump means (22) to prevent communication of pressurized fuel to said nozzle means (13).

2. The fuel injection system (10) of^" claim 1 further including an electrical power source (56), and wherein said drive means (40) includes electronic drive means (40) for continuously rotating said rotor means (27) in response to activation of said electrical power source (56) and wherein said actuation of said rotor means (27) is responsive to deactivation of said electrical power source (56).

3. The fuel injection system (10) of claim 2 wherein said shut-off means (54) includes solenoid means (55) for positioning said rotor means (27) for controlling the pressurization of fuel in said pump means (22) to start and stop ejection of fuel through said nozzle means (13) in response to continuous rotation of said rotor means (27) and biasing means (62) for actuating said rotor means (27) to effect said venting of said pump means (22) to prevent communication of pressurized fuel to said nozzle means (13) in response to deactivation of said electrical power source (56) and said solenoid means ((55).

4. The fuel injection system (10) of claim 3 wherein said electronic drive means (40) includes an output shaft (60), said rotor means (27) includes a rotor (29), and said shut-off means (54) further includes means (61) for permitting relative axial movement between said output shaft (60) and said rotor (29).

5. The fuel injection system (10) of claim 4 further including a connecting shaft (59) interconnected between said output shaft (60) and said rotor (29) and wherein said last-mentioned means (61) includes spline means (61) for connecting said output shaft (60) to said connecting shaft (29) for simultaneous rotation therewith and for permitting said connecting shaft (59) to move axially relative to said output shaft (60).

6. The fuel injection system (10) of claim 5 wherein said biasing means (62) includes a compression coil spring (62) mounted between said output shaft (60) and said rotor (29).

7. The fuel injection system (10) of claim 6 wherein said solenoid means (55) includes a reciprocal plunger (57) connected to said rotor (29) for simultaneous axial movement therewith.

8. A fuel injection system (10) comprising: a source of main fuel (18), a main fuel nozzle (13), a high-pressure main fuel pump (22) having suction and compression strokes, said pump (22) defining a pumping cavity (25) therein connected to said main fuel nozzle (13), first rotor means (27) for controlling the pressurization of main fuel in the pumping cavity (25) of said main fuel pump (22) to start and stop ejection of main fuel through said main nozzle (13) in response to continuous rotation of said rotor means (27), drive means (40) for continuously rotating said rotor means (27), and shut-off means (54) for communicating the pumping cavity (25) of said main fuel pump (22) to said source (18) nozzle said rotor means (27), in response to deactivation of said drive means (40).

9. The fuel injection system (10) of claim 8 wherein said rotor means (27) includes a first rotor (29) connected to the pumping cavity (25) of said main fuel pump (22) and a second rotor (36) interconnected between said first rotor (29) and said source (18).

10. The fuel injection system (10) of claim 9 further including a source of pilot fuel (14), a pilot nozzle (12), a high-pressure pilot fuel pump (47) having suction and compression strokes, said pilot fuel pump (47) defining a pumping cavity (49) therein connected to said pilot fuel nozzle (12), and second rotor means (44) for controlling pressurization of pilot fuel in the pumping cavity (49) of said pilot fuel pump (47) to start and stop ejection of pilot fuel through said pilot fuel nozzle (12) in response to continuous rotation of said second rotary means (44) by said drive means (40), said second rotary means (44) being connected to the first rotor (29) of said first rotor means (27) for simultaneous rotation therewith, and said shut-off means (54) further operative for actuating each of said first (27) and second (44) rotor means to vent the pumping cavities (25,49) of each of said main fuel pump (22) and said pilot fuel pump (47) to their respective sources (18,14) in response to deactivation of said drive means (40).

11. The fuel injection system (10) of claim 8 further including an electrical power source (56), and wherein said drive means (40) includes electronic drive means (40) for continuously rotating said first rotor means (27) in response to activation of said electrical power source (56) and wherein said shut-off means (54) is responsive to deactivation of said electrical oower source (56). -19-

12. The fuel injection system (10) of claim 11 wherein said shut-off means (54) includes solenoid means (55) for positioning said first rotor means (27) for controlling the pressurization of fuel in said main fuel pump (22) to start and stop ejection of fuel through said main fuel nozzle (13) in response to continuous rotation of said first rotor means (27) and biasing means (62) for actuating said first rotor means (27) to effect said communication of the pumping cavity (25) of said main fuel (22) to prevent communication of pressurized fuel to said main fuel nozzle (13) in response to deactivation of said electrical power source (56) and said solenoid means (55).

13. The fuel injection system (10) of claim 12 wherein said electronic drive means (40) includes an output shaft (60), said first rotor means (27) includes a rotor (29), and said shut- off means (54) further includes means (61) for permitting relative axial movement between- said output shaft (60) and said rotor (29).

14. The fuel injection system (10) of claim 13 further including a connecting shaft (59) interconnected between said output shaft (60) and said rotor (29) and wherein said last-mentioned means (61) includes spline means (61) for connecting said output shaft (60) to said connecting shaft (29) for simultaneous rotation therewith and for permitting said connecting shaft (59) to move axially relative to said output shaft (60).

15. The fuel injection system (10) of claim 14 wherein said biasing means (62) includes a compression coil spring (62) mounted between said output shaft (60) and said rotor (29).

16. _ The fuel injection system (10) of claim 15 wherein said solenoid means (55) includes a reciprocal plunger (57) connected to said rotor (29) for simultaneous axial movement therewith.