US3865091A

US3865091A - Excess fuel starting device for diesel engines

Info

Publication number: US3865091A
Application number: US443196A
Authority: US
Inventors: Norvan W Bostwick; Ignace J Daborowski
Original assignee: Ambac Industries Inc
Current assignee: Ambac Industries Inc; AIL Corp
Priority date: 1974-02-19
Filing date: 1974-02-19
Publication date: 1975-02-11
Anticipated expiration: 1992-02-11

Abstract

A device for automatically supplying excess fuel during starting to a diesel engine regulated by a mechanical variable speed governor. Means are provided on the governor flyweights for engaging and restricting movement of the governor sleeve during engine cranking. The fulcrum lever pivot point on the sleeve is thus fixed during cranking and the movement of the upper end of the fulcrum lever and the fuel control rod are directly controlled by the throttle setting. An excess fuel actuator on the operating shaft serves to rotate the fulcrum lever during cranking against the spring loaded full load stop plate, compressing the spring and producing an excess fuel position of the fuel control rod. Upon engine starting, the flyweights disengage from the governor sleeve and serve their normal governing function. The device cannot reset to provide excess fuel until the engine has completely stopped.

Description

Ilnited States Patent 1191 Eostwiek et a1.

[ 1 Feb. 11, 1975 EXCESS FUEL STARTING DEVICE FOR DIESEL ENGINES [73] Assignees Ambac Industries, Inc., Springfield,

Mass.

22 Filed: Feb. 19, 1974 21 Appl. No.: 443,196

[52] U.S. Cl 123/139 ST, 123/179 L [51] Int. Cl. E02m 59/412 [58] Field of Search 123/139 ST, 179 L, 139 T, 123/139 AZ, 140 R [56] References Cited UNlTED STATES PATENTS 2,619,080 11/1952 Weber 123/139 ST 3,311,102 3/1967 Voigt 123/179 L FOREIGN PATENTS OR APPLICATIONS 124,144 4/1931 Australia 123/140 R Primary E.raminerCharles J. Myhre Assistant ExaminerW. Rutledge, Jr. Attorney, Agent, or Firm-Howson and Howson [5 7] ABSTRACT A device for automatically supplying excess fuel during starting to a diesel engine regulated by a mechanical variable speed governor. Means are provided on the governor flyweights for engaging and restricting movement of the governor sleeve during engine cranking. The fulcrum lever pivot point on the sleeve is thus fixed during cranking and the movement of the upper end of the fulcrum lever and the fuel control rod are directly controlled by the throttle setting. An excess fuel actuator on the operating shaft serves to rotate the fulcrum lever during cranking against the spring loaded full load stop plate, compressing the spring and producing an excess fuel position of the fuel control rod. Upon engine starting, the flyweights disengage from the governor sleeve and serve their normal governing function. The device cannot reset to provide excess fuel until the engine has completely stopped.

6 Claims, 6 Drawing Figures PATENTEB FEB I I I975 SHEET 2 [IF 3 NOE PATEHIED FEB I 1 I975 SHEEI 3 OF 3 EXCESS FUEL STARTING DEVICE FOR DIESEL ENGINES The present invention relates generally to diesel engine fuel control systems and relates more particularly to a device incorporated in a diesel engine governor for supplying excess fuel during engine starting.

Diesel engines require a substantially larger amount of fuel during starting than during any other phase of operation. The first devices for providing excess starting fuel required manual actuation by the operator. More recent developments have included devices for automatically providing excess fuel during engine cranking. For example, in US. Pats. Nos. 3,31 l,ll and 3,31 1,102, assigned with the present application to a common assignee, related forms of a hydraulically adjusted governor full load stop positioned by engine lube oil pressure are disclosed. In each patented structure, the stop is spring driven to an excess fuel position until the spring force is overcome, by the lube oil pressure acting within a piston assembly connected to the full load stop. Although effective for carrying out their intended function, these devices are relatively complex and hence expensive.

The present invention, by contrast, is a relatively simple mechanical device which does not involve the flow passages, pistons, seals, etc., characteristic of hydraulic equipment. In the present device, the governor fulcrum lever full load stop plate is spring loaded into a normal full load position, but is displaceable against the spring force during cranking. The governor flyweights are provided with lock plates at their outer ends which, when the flyweights are at rest in their innermost position, are adapted to engage the governor sleeve and restrict travel of the sleeve away from the flyweights along the governor shaft. With the governor sleeve position and hence the fulcrum lever pivot point being essentially fixed during cranking, movement of the lower end of the fulcrum lever by the throttle linkage operating shaft produces a positive displacement of its upper end. An actuator is provided to directly connect the throttle linkage and fulcrum lever when the operating lever is fully advanced and the engine is stopped whereby the fulcrum lever will displace the full load stop against its compression spring to a predetermined excess fuel position. When the engine starts and reaches a predetermined speed, the flyweights automatically release the sleeve, permitting normal governor operation. Excess fuel cannot be again provided until the engine is completely stopped and the flyweights have returned to their rest position against the sleeve.

It is accordingly a first object of the present invention to provide a fully automatic mechanical device for providing excess fuel to a diesel engine during starting.

A further object of the invention is to provide a device as described which will continue to provide excess fuel until the engine has reached a speed sufficient to insure against engine stalling.

Another object of the invention is to provide a device as described which cannot return to an excess fuel delivery position until the engine has completely stopped.

Still another object of the invention is to provide a device as described having a relatively simple structure which can be readily adapted to a conventional fuel injection pump governor design with a minimum amount of modification.

Additional objects and advantages of the invention will be more readily apparent from the following detailed description of an embodiment thereof when taken together with the accompanying drawings in which:

FIG. 1 is a cutaway view partly in section of a diesel engine governor having an excess fuel starting device in accordance with the present invention, the governor being shown in the stopped position;

FIG. 2 is a view similar to FIG. 1 with the governor shown in the excess fuel position as obtained during engine cranking;

FIG. 3 is a view similar to FIG. 1, showing the governor in the normal full load running position;

FIG. 4 is a view partly in section taken along line 44 of FIG. 2;

FIG. 5 is an enlarged fragmentary sectional view showing the relationship of one of the flyweight lock plates with the governor locking sleeve in the engine shut off condition; and

FIG. 6 is a view similar to FIG. 5 showing the relationship of one of the flyweight lock plates and the governor locking sleeve during engine cranking.

Referring to the drawings and. particularly FIG. 1 thereof, a fuel injection pump governor generally designated 10 is shown operatively connected with a fuel injection pump 12, only a portion of the housing of which is shown at the left side of the drawing. The governor is enclosed within a governor housing 14 secured to the fuel injection pump housing and, with the exception of the present invention embodied therein, is of a conventional mechanical variable speed type.

The governor includes a governor shaft 16 which is driven at a speed commensurate with engine speed by a gear connection to the fuel injection pump cam shaft (connection not shown). Mounted on the governor shaft for rotation therewith is the flyweight assembly 18 which functions to position the nonrotating governor sleeve assembly 20 on the shaft 16 in accordance with engine speed, there being a specific sleeve position for any given engine speed during normal governor opera tion.

Considering this mechanism in detail, the flyweight assembly 18 includes a sleeve 22 secured to the larger diameter portion 16a of the shaft 16 for rotation therewith. The flyweight assembly includes a bearing 24 having an inner race fitted to the flyweight sleeve and an outer race supported by the interior housing portion 26. The bearing assembly 24 thus serves to journal the shaft 16 within the governor housing.

The flyweight assembly 18 includes a spider 28 mounted on the spider sleeve 22 and resiliently secured against the shoulder 22a thereof for rotation therewith by spring washers 30 bearing against the collar 32 of the governor shaft 16. Flyweights 34 are pivotally secured to the spider 28 by pins 36 and are free to pivot radially about the pins in response to centrifugal forces.

At its right hand end, the shaft 16 passes through and is supported by the governor housing at 38 and extends into and drives the gear type fuel supply pump 40. Pump drive gear 42 mounted on the right hand end of the shaft 16 meshes with the gear 44 mounted on stub shaft 46 to provide a positive displacement fuel pumping action. Since the fuel pump 40 is not related to the present invention, no further description of its structure or operation is deemed necessary.

The governor sleeve assembly includes sleeve element 48.comprising an essentially hollow member having an inner sleeve portion 50 extending integrally from the left end thereof and which is disposed for axially sliding movement along the governor shaft 16. As shown in FIG. 1, the left hand end of the inner sleeve 50 is adapted to abut the shaft collar 32 when the governor is in the rest position. The right hand end of the sleeve element 48 is open, permitting the entry of inner and

outer springs

52 and 54 thereinto, the inner spring 52 seating on the left hand end of the sleeve element 48, while the outer spring 54 seats on a sleeve element shoulder 56. The

springs

52 and 54 are in compression and are respectively seated at the right hand ends on the spring seats 58 and 60 supported by the governor housing. A shaft seal 62 is provided between the spring seat 58 and the housing passage 38.

As illustrated in FIG. 1, when the engine is stopped, the

springs

52 and 54 urge the sleeve assembly 20 to its extreme left end position with the inner sleeve 50 abutting the shaft collar 32. A locking sleeve 64 partially overlies the sleeve element 48 at its left end and serves a purpose described herebelow. A teflon washer 66 is disposed around the inner sleeve 50 adjacent the locking sleeve 64 and is secured in place by a thrust washer 68 and its retaining ring 70. An additional thrust washer 72 is disposed adjacent thrust washer 68 on the inner sleeve 50 and is engaged by the nose portions 74 of the flyweights 34. The expansionof the flyweights due to centrifugal force will result in a movement of the sleeve assembly to the right until the spring forces and the centrifugal flyweight forces are equal. There will accordingly be a different position of the sleeve assembly 20 on the governor shaft 16 for each speed of the engine over its normal range of operation. I

A yoke-shaped fulcrum lever 76, as most readily seen in FIG. 4, is pivotally and slidably connected with the governor sleeve assembly 20 by means of pins 78, the inwardly extending heads 79 of which are slidably disposed in the vertical slots 80 of the sleeve element 48. At its lower end, the fulcrum lever 76 is pivotally connected by pivot pin 82 to the trunnion lever 84 which in turn is pivotally mounted on but not secured to the operating lever shaft 86 which extends transversely across and is journalled within the lower portion of the governor housing. On operating lever shaft end 87, which extends through the housing, is mounted the operating lever 88 which is directly connected to the engine throttle linkage. Advancing the throttle will rotate the operating lever shaft in a clockwise direction as viewed in FIG. 1.

The trunnion lever 84 is connected for rotation with the operating shaft lever 86 by means of a torsion spring 90 attached to the shaft and acting on the trunnion lever (connection not shown) to resiliently urge the trunnion lever to rotate in a clockwise direction with the operating lever. In view of the resilient nature of the spring connection, the trunnion lever may lag behind the operating lever shaft under certain operating conditions for reasons explained herebelow. The rotation ofthe operating lever shaft in a clockwise direction is limited by an adjustable stop screw 92 which is aligned to engage the stop plate 94 on the operating lever shaft. Similarly, an adjustable stop screw 96 engages the stop plate 98 on the operating lever shaft to limit rotation of the shaft in a counterclockwise direction as illustrated in FIG. 1 wherein these elements are shown in engagement.

Connected to the upper end of the fulcrum lever 76 for actuation thereby is the fuel control rod 100 which as shown in broken lines extends into the fuel injection pump and directly controls the amount of fuel delivered to the engine by each stroke of the injection pump plunger. As shown in FIG. 4, the connection of the fuel control rod 100 to the fulcrum lever 76 includes a connecting link 102 which is pivotally mounted on a pivot pin 104 passing through the upper end of the fulcrum lever.

The rotation of the upper end of the fulcrum lever 76 in a counterclockwise direction as viewed in FIG. 1 is limited by the engagement of either the torque cam 106, located at the extreme upper end of the fulcrum lever, or the droop screw 108, spaced below the torque cam, with the stop plate mounted on the stop plate support assembly 112 at the upper end of the governor housing. The angle at which the torque cam is locked to the upper end of the fulcrum lever and the setting of the droop screw on the fulcrum lever are critical adjustments which determine the operating characteristics of the engine under full load conditions over the engine operating speed range.

The governor structure thus far described is essentially conventional, and its operation is well understood by those skilled in the fuel injection art and will thus be only briefly considered. The governor mechanism is designed to automatically control the movement of the fuel control rod 100 to (a) correlate the fuel delivery at any given throttle setting with engine speed, (b) prevent stalling at low idle and over speed at high idle, and

(c) to prevent overloading of the engine over the full operating speed range.

viewed in FIG. 1 will increase the amount of fuel delivered to the engine while the movement of the control rod to the right will decrease the fuel delivery. It will accordingly be apparent that a counterclockwise rotation of the fulcrum lever, which might for example be produced by a clockwise rotation of the operating lever or a leftward movement of the governor sleeve assembly, will produce an increase in the fuel delivery, unless the full load stop is engaged by the torque cam or the droop screw. The throttle setting is established by the operator through the throttle linkage and operating lever, and the trunnion lever by its spring connection with the operating lever will establish the position of the lower end of the fulcrum lever. The governor sleeve position is established by the speed at which the engine is running, the flyweights 34 extending radially outwardly under centrifugal force and urging the governor sleeve element 48 to the right against the forces of

springs

52 and 54. The position of the upper end of the fulcrum lever, and hence the position of the fuel control rod 100 will thus be a result of both the engine throttle setting and the engine speed, at least for loads less than full load. Under these conditions, with a fixed throttle setting, the fuel delivery will decrease with increased speed as the governor sleeve is moved to the right, and will increase with decreased speed as the sleeve moves to the left.

Under a full load condition, depending on the speed of the engine, either the torque cam 106 or the droop screw 108 will engage the full load stop 110 as shown for example in FIG. 3. In FIG. 3, the droop screw is engaging the full load stop, essentially preventing an increase in fuel delivery despite the fact that the throttle linkage is in the fully advanced position with the stop plate 94 against the stop screw 92. Even if the engine speed should decrease, additional fuel will not be supplied. As the governor sleeve moves to the left with decreasing speed, the torsion spring connection of the trunnion lever with the operating shaft permits the trunnion lever to move counterclockwise with respect to the operating lever shaft as illustrated in FIG. 3, thereby allowing governor sleeve movement without any corresponding movement of either the fulcrum lever upper end or the operating lever shaft. In fact, fuel delivery I may decrease slightly with decreased speed due to the connection of the fuel control rod to the fulcrum lever at a point spaced above the droop screw. The purpose of the torsion spring connection of the trunnion lever to the operating lever shaft, namely to permit the override of the fuel delivery by the full load stop, is thus clearly illustrated by the operating conditions shown in FIG. 3.

The improvement of the present invention is a device which automatically provides a delivery of an excess amount of fuel during engine cranking, the excess fuel exceeding the fuel delivery during engine full load operation. The invention includes a spring loaded mounting of the stop plate 110 on the assembly 112. The stop plate 110 is slidable on a supporting screw 114 extending from the assembly 112 and is provided with a guide pin I16 slidable within a bore 118 of the assembly. A compression spring 120 disposed around the guide pin and extending between the assembly 112 and the stop plate serves to hold the stop plate in its normal full load position against the head of the support screw 114. As shown in the excess fuel position of FIG. 2, however, the stop plate during cranking is moved to the left against the force of the compression spring 120 to an excess fuel position, thereby moving the fuel control rod 100 to the left to deliver fuel in excess of the normal full load fuel load delivery.

In order to prevent movement of the governor sleeve during cranking, locking means are provided on the flyweights 34 to hold the flyweights in engagement with the governor sleeve until a predetermined speed has been reached, in effect holding the governor sleeve in essentially its shut off position. This locking means includes, as shown in detail in FIGS. 5 and 6, lock plates 124 secured to the tips of the flyweights 34 by screws 126. The lock plates have beveled locking surfaces 128 adapted to cooperate with juxtaposed locking surfaces 130 of the locking sleeve 64 against which the flyweights are disposed in the engine shut off condition. As shown in FIGS. 1 and 5, when the engine is stopped and the throttle setting is in the fully retarded position, there is a slight spacing between the locking

surfaces

128 and 130 of the lock plates and the locking sleeve. When the throttle is advanced, however, the movement of the fulcrum lever against the stop plate at its upper end and its continued rotation by the throttle advance at its lower end moves the governor sleeve to the right to close the spacing between the lock surfaces 128 and 130 as shown in FIG. 6. The governor sleeve cannot move further to the right, being heldcaptive by the flyweight lock plates in engagement with the locking sleeve.

As indicated above, the connection of the throttle linkage to the trunnion lever and hence the fulcrum lever is normally by means of the torsion spring 90. However, for purposes of providing an excess fuel position of the stop plate, a direct connection ofthe throttle linkage with the trunnion lever and hence the fulcrum lever is necessary to overcome the force of the full load stop plate spring 120. This direct connection is provided by means of an extending end 82a of the pivot pin 82 connecting the fulcrum lever 76 with the trunnion lever 84. The pivot pin extending end 82a is disposed in a slot 132 in the operating lever shaft stop plate 94 and, during normal engine operation, does not interfere with the torsion spring loaded connection between the trunnion lever 84 and the operating lever shaft 86 as shown in FIG. 3 wherein the trunnion lever is displaced from its normal disposition with respect to the operating lever shaft. However, during cranking of the engine and only during this condition, the full advance of the throttle linkage to rotate the operating lever shaft stop plate 94 against the stop screw 92 as shown in FIG. 2, because of the locked position of the governor sleeve assembly 20, rotates the operating lever shaft clockwise against the force of the torsion spring 90 well beyond any differential position between the trunnion lever and operating lever shaft encountered in normal engine operation until the pivot pin extension 82a engages the end of the slot 132 in the operating lever shaft stop plate 94. With the governor sleeve locked to hold stationary the central pivot point of the fulcrum lever, and with the throttle linkage directly urging the lower end of the fulcrum lever to the right, the engagement of the upper end of the fulcrum lever throughthe torque cam 106 with the stop plate 110 will move the stop plate against the force of spring 120 into the excess fuel position shown in FIG. 2.

To operate the present excess fuel device, with the engine in the shut off position of FIG. I, the operator need only advance the throttle to the fully advanced setting shown in FIG. 2. As indicated above, because of the rest position of the flyweights against the locking sleeve 64, the clockwise rotation of the trunnion lever in response to the throttle advance swings the fulcrum lever in a counterclockwise movement against the stop plate and moves the governor sleeve slightly to the right to lock the locking surfaces 128 and 130 as illustrated in FIG. 6. With the governor sleeve locked against further movement along the governor shaft, the rotation of the operating lever shaft to the fully advanced position determined by stop screw 92 results in an engagement of the pin extension 82a with the end of the slot 132, thereby bypassing the torsion spring and providing a direct connection of the throttle linkage with the fulcrum lever sufficient to compress the spring and allow the stop plate to move to the excess fuel position. The movement of the stop plate to the excess fuel position allows the fulcrum lever to move further to the left beyond the normal full load position, thereby providing an excess fuel position of the fuel control rod 100.

After the engine starts and reaches a predetermined speed, the centrifugal force acting on the flyweights 34 causes the locking surfaces 128 and to slip apart, thus freeing the flyweights and permitting their normal operating function of positioning the governor sleeve assembly in accordance with engine speed. Once the flyweights have separated from the locking sleeve, the governor sleeve is moved by the flyweights to the right, thereby carrying the fulcrum lever to the right away from the full load stop which returns to its normal position against the head of the support screw 114.

Should the throttle be released upon engine starting prior to the engine reaching said predetermined speed, the counterclockwise rotation of the trunnion lever will move the upper end of the fulcrum lever away from the full load stop, permitting the full load stop to return to its normal position. At the same time, the rightward pressure on the governor sleeve caused by the full load throttle setting is released, allowing the locking surfaces 128 and 130 to release prior to the engine reaching the predetermined speed referred to above.

The stop plate spring 120 has a sufficient force to resist movement of the stop plate 110 under all operating conditions except when the governor sleeve is locked in position by the flyweights during engine cranking. It will be apparent that once the engine has started, the flyweight lock plates cannot reengage the locking sleeve until the engine has stopped since the engine rotation will hold the flyweights out away from the governor sleeve which causes the governor sleeve to be moved to the right, placing the locking sleeve out of reach of the flyweight lock plates. The device is thus not only automatic in operation upon starting of the engine but also automatically prevents any possibility of excess fuel delivery until the engine has completely stopped. When the operator holds the full throttle position during starting, the device automatically holds the excess fuel delivery until such time as a predetermined speed has been reached, thereby minimizing the chance of stalling during starting.

Manifestly, changes in details of construction can be effected by those skilled in the art without departing from the spirit and the scope of the invention as defined in and limited solely by the appended claims.

We claim:

1. In a diesel engine fuel injection pump governor having a governor shaft driven at a speed proportional to engine speed, a non-rotating sleeve slidably disposed on said shaft, a flyweight assembly mounted on said shaft for rotation therewith and having at least one flyweight rotatably mounted to swing radially outwardly in response to centrifugal forces during rotation of said shaft, said flyweight in the rest position being disposed in contiguous relation to said sleeve, means on said flyweight for moving said sleeve along said shaft in response to radial movement of said flyweight, spring means acting on said sleeve opposing sleeve movement by said flyweight, a fulcrum lever pivotally connected at a point remote from its ends to said sleeve, an engine fuel control rod, a first end of said fulcrum lever being connected to said engine fuel control rod, a full load stop plate adjacent said first fulcrum lever end, means on said fulcrum lever end for engaging said stop plate to limit the travel of said fulcrum lever end and control the full load fuel delivery position of said fuel control rod, a trunnion lever pivotally connected to the second end of said fulcrum lever, an operating lever shaft rotatably disposed adjacent said fulcrum lever, said trunnion lever being rotatably mounted on said operating lever shaft, spring means connecting said trunnion lever with said operating lever shaft to resiliently rotate said trunnion lever with said operating lever shaft in at least one direction, and an operating lever connected to said operating lever shaft, the improvement comprising spring means associated with said stop plate permitting movement of said stop plate to an excess fuel position under a predetermined force of said fulcrum lever thereagainst, means on said flyweight for locking said flyweight to said sleeve during cranking of the engine to prevent radial flyweight movement and axial sleeve movement, and means connecting said operating lever shaft directly with said fulcrum lever second end during engine cranking at full throttle setting to provide said predetermined force of said fulcrum lever against said full load stop, thereby establishing an excess fuel position of said stop and of said fuel control rod.

2. The invention as claimed in claim 1 wherein said locking means on said flyweight is adapted to release said flyweight from said sleeve when the engine reaches a predetermined speed.

3. The invention as claimed in claim 2 wherein said locking means comprises a lock plate on the end of said flyweight, a locking sleeve associated with said governor sleeve, and locking surfaces on each of said lock plate and said locking sleeve adapted for engagement to lock the flyweight to said governor sleeve during engine cranking.

4. The invention as claimed in claim 3 wherein said locking surfaces are beveled surfaces adapted to frictionally release under the influence of the centrifugal flyweight force when the engine reaches a predetermined speed.

5. The invention as claimed in claim 1 wherein said stop plate is slidably supported on a support screw and wherein said spring means associated with said stop plate comprises a compression spring adapted to position said stop plate against the head of said support screw against any force applied thereto by said fulcrum lever except during engine cranking.

6. The invention as claimed in claim 1 wherein said means for directly connecting said operating lever shaft to said second end of said fulcrum lever during engine cranking comprises a pin extending from the second end of said fulcrum lever, a plate extending radially from said operating lever shaft, and a slot in said latter plate for receiving said pin, said pin engaging the end of said slot to directly connect the operating lever shaft and fulcrum lever only when said governor sleeve is locked by said flyweight locking means and said operating lever is set at the full throttle position.