US3392590A - Governor for fuel injection pump assembly - Google Patents

Description

July 16, 1968 L. REPKQ ET AL 3,392,590

GOVERNOR FOR FUEL INJECTION PUMP ASSEMBLY Original Filed July 16, 1965 5 Sheets-Sheet 1 9 I I I l INVENTORS LOUIS L. REPKO ALADAR O. SIMKC July 16, 1968 L.- L.- REPKO ET GOVERNOR FOR FUEL INJECTION PUMP ASSEMBLY Original Filed July 16, 1965 5 Sheets-Sheet 2 F'IG.3

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LOUIS L. REPKO ALADAR O. SIMKO I 'FVTOR'S July 16, 1968 L. I... REPKO ET GOVERNQRFOR- FUEIJ INJECTION PUMP ASSEMBLY Original Filed July 16. 1965 5 Sheets-Sheet 4,

ALADAR INVENTORS United States Patent 3,392,590 GOVERNOR FOR FUEL INJECTION PUMP ASSEMBLY "Louis L. Repko and Aladar O. Simko, Detroit, Mich., as-

signors to Ford Motor Company, Dearboru, Mich., a corporation of Delaware Original application July 16, 1965, Ser. No. 472,422, now Patent No. 3,319,568, dated May 16, 1967. Divided and this application Jan. 3, 1967, Ser. No. 623,782

1 Claim. (Cl. 73-534) ABSTRACT OF THE DISCLOSURE This is a division of S.N. 472,422, Fuel Injection Pump Assembly, filed July 16, 1965, now Patent No. 3,319,568.

This invention relates to a motor vehicle type fuel pump. More particularly, it relates to a pump assembly of the injection type.

A primary object of the invention is to provide a fuel injection pump that is relatively simple in construction and economical to manufacture, and yet provides all of .the necessary control functions for proper operation of an internal combustion engine at all load and speed ranges by the use of a single fuel metering valve having axial and rotational movements controlled primarily by the movements of the vehicle accelerator pedal and a single engine speed responsive governor means.

These control functions include those for idle speed control, speed sensitive timing advance, torque or load control, deceleration fuel cut-off, and overfueling for start-up. They also include a control to prevent afterrunning of the engine.

The invention provides the above objectives by constructing a fuel injection pump assembly with a fluid flow control member having a single metering helix that is movable bothaxially and rotationally to progressively and consecutively close fuel spill ports connected to the discharge portion of a number of fuel pump plunger barrels. The various movements of the metering helix are controlled entirely by the individual or collective movements of the vehicle accelerator pedal and an engine speed responsive governor. The governor provides desired control functions with only a single set of Weights. The invention thus provides both internal and external controls to provide the desired fuel schedule throughout the entire rangeof operation of the assembly.

In general, the construction includes .a housing having a central bore in which a shaft is mounted for longitudinal as well as rotational movements. One end of the shaft slidably splined to a power input member that drives a plunger-type fuel pump to inject fuel consecutively past individual delivery valves into the engine. The quantity of fuel injected is controlled by fuel spill lines or ports that are connected to each of the pump plunger barrels. A metering valve surrounding the shaft controls admission of fuelto the bore from a supply line, and has a single metering helix that variably closes or opens the spill ports as a function of the longitudinal and rotational movements of the valve and the shaft. The valve is movable longitudinally by the vehicle accelerator pedal, and

both longitudinally and rotatably at times by a speed responsive governor.

In operation, fora prime start, the accelerator pedal is fully depressed. This locates the metering helix to close the spill holes for substantially the entire up-stroke of the pump plungers so that the overfueling required for startmg purposes is provided. Subsequent engine idle condition is obtained by releasing the accelerator pedal to its idle position to permit a preloaded spring and a flyweight governor to position the metering helix so that the fuel spill holes are opened to the correct degree.

For normal operation above idle and below a predetermined speed, the governor is inoperative to axially move the metering helix, and the volume of fuel injected is controlled primarily as a function of the movement of the accelerator pedal so that the pump assembly is sensitive to load and torque demands. Above the predetermined drive shaft speed, When injection timing advance is desired, the speed responsive means and other optional means cooperates with the accelerator pedal movement to cause both axial and rotative movements of the metering helix relative to the drive shaft to advance the schedule of injection and change of the volume of fuel to correspond to engine needs.

Deceleration fuel cut-off is provided by releasing the accelerator pedal to its idle position to permit the speed responsive means first to move the metering helix to a position wherein the spill holes are substantially wide open, thereby cutting off all fuel injection; and subsequently, upon reaching the idle speed range, to return the metering helix to the idle speed position. The invention further provides a suitable external fuel shut-off control to prevent afterrunning once the ignition has been shut off.

It is a further object of the invention, therefore, to provide a fuel injection pump assembly that varies the amount of fuel delivered to the engine cylinders as a function of the axial positioning of a single fuel metering control member to thereby control the output of the engine when less than maximum torque is required.

A still further object of the invention is to provide a fuel injection pump assembly that matches the maximumfuel flow curve to the needs of the engine throughout the speed range when the engine is running at Wide-open throttle condition, this being provided by a fuel metering means having an automatically variable load position.

Another object of the invention is to provide a fuel injection pump assembly that provides, for engine starting purposes, an amount of fuel far greater than that provided during full load operation, by means of a single flow metering element controlling the vent of fuel from the pump plunger barrels during the upstroke of the plungers.

A still further object of the invention is to provide a fuel injection pump assembly that provides for injection speed advance adjustments so that the injection timing can be advanced and the quantity of fuel modified as a function of the speed to provide more economical and efficient operation.

It is a still further object of the invention to provide a fuel injection pump assembly that properly schedules the flow of fuel to provide all the necessary control functions during the various acceleration phases of operation of the vehicle, and yet completely interrupts the fiow of fuel during deceleration phases and overspeed, to provide efficient and economical operation of the engine and eliminate an oversupply of fuel, thereby retarding the formation of smog producing elements in the engine exhaust gases.

Other objects, features and advantages of the invention will become apparent upon reference to the succeeding, detailed description thereof, and to the drawings illustrating the preferred embodiments thereof; wherein,

FIGURE 1 is a front-elevational view of a fuel injection pump assembly embodying the invention;

FIGURE 2 is an enlarged cross-sectional view of one embodiment of the invention;

FIGURE 3 is a schematic representation of the FIG- URE 2 showing;

FIGURE 3A is an enlarged cross-sectional view of a detail of FIGURE 2;

FIGURES 4, 5 and 6 are enlarged cross-sectional v1ews of details of a modification of the FIGURE 2 construction, FIGURES 5 and 6 being taken on planes indicated by and viewed in the direction of the arrows 5-5 and 6-6, respectively, of FIGURE 4;

FIGURE 7 is a cross-sectional view with parts broken away of another embodiment of the invention;

FIGURE 8 is a schematic representation of the FIG- URE 7 embodiment;

FIGURE 9 is a cross-sectional view of a portion of the FIGURE 7 embodiment rotated clockwise 90 and taken on a plane indicated by and viewed in the direction of the arrows 9-9 of FIGURE 7;

FIGURES 10, 11 and 12 are cross-sectlonal v1ews taken on planes indicated by and viewed in the direction of the arrows 10-10, 11-11 and 12-12 of FIGURE 9;

FIGURE 13 is an enlarged cross-sectional view of a detail of FIGURE 7; and,

FIGURES 14, 15 and 16 are cross-sectional views of modifications of the FIGURE 13 showing.

FIGURE 1 shows an external view of the assembly It includes a first housing portion 1 enclosing the actuat ng mechanism for a plunger-type fuel pump, a second housing portion 2 enclosing the pump plungers and having a number of fuel discharge outlets 10 that are each adapted to be connected by an external hose to an individual fuel 1njecti-on nozzle, and an upper housing portion 11. The upper portion includes a window 12 for observing the degree of injection advance; that is, for observing the timing of the pump to the engine, which will be described in more detail later. It also includes a window 14 adjacent an internal fuel reservoir to observe for air bubbles, etc. in the fuel for fuel vapor evaluation purposes. An externally controlled linkage 16 forms a part of the engine accelerator pedal linkage, and partially controls the discharge of fuel through outlets 10 in a maner to be described.

More specifically, as shown in FIGURE 2, pump housing 18 has several sections bolted or otherwise secured together. These include a cover portion 20, a hollow upper portion 22 containing a flyweight governor mechanism, a central portion 26 containing the fuel pump plungers and fuel flow metering sleeve valve, and a lower portion 28 enclosing the drive shaft and pump drive plate assembly.

Lower housing portion 28 has a central bore 30 in which is rotatably mounted a tubular drive shaft 32 on side bearings 33. The drive for this shaft is not shown, but it would, in general, be driven by a geared take-off from the engine cam shaft. The upper part of shaft 32 is formed integral with the drive plate 34 of a known type of pump,

having an angled drive surface 36. Plate 34 is rotatably mounted on thrust bearings 40, and has, in this case, eight (only two shown) circumferentially spaced slippers 42 projecting through suitable apertures 44 m a connecting disc 46. A single central spring 47 retains all of the slippers against the drive plate 34.

Each of the slippers has a universal connection with the ball end 48 of a reciprocating-type piston or plunger 50 axially movable in a bore or barrel 52. Grooves 54 and 54' are provided for fuel leak-off and lubrication-sealing purposes, respectively. The upper end of each barrel 52 is intersected by crossbores 56 and 58 in housing portion 26, the number corresponding to the number of cylinders in the engine to which the fuel pump is connected. Bores 56 constitute discharge passages for fuel leading to delivery valves 59. Passages 58 constitute spill holes or ports connected to a central bore or fluid chamber 60 in housing section 26.

A fuel storage area 66 is provided on one side of pump housing portion 11, and is connected to chamber 60 by intersecting passages 62 and 64. An external fuel transfer pump (not shown) would be connected to passage 62.

In general, each plunger is fed with fuel from the chamber 60 through its own spill hole during the suction stroke of the plunger. During the plunger upstroke, fuel is displaced either back into chamber 60 or past the delivery valve and out through the nozzle.

Fuel delivery from the pump is controlled by proper phasing of a sleeve valve metering helix 78 with plunger displacement. The metering sleeve valve 70 has both axial and rotational movements to variably close or open spill ports 58. This valve is of the spool type, and has upper and lower lands 72 and 74 connected by a necked portion 76 of reduced diameter. The land diameters are such as to effectively seal the annular internal fuel reservoir defined between the lands so that axial movement of the valve will control fuel flow into chamber 60 from passage 62, and also the passage of fuel into and out of spill ports 58. Lower land 74 has a raised circumferentially extending portion 78 in the shape of a helix that is integral with the valve and moves axially and rotatably with it, in a manner to be described, to progressively close or open spill ports 58.

The metering sleeve valve 70 surrounds an extension 82 of drive shaft 32, and can be moved both axially and rotatably with respect to it in the following manner. A tubular pump timing bushing is bolted to drive shaft 32, which is internally splined to the lower end of shaft 82. The two shafts are further connected by a pin 84 that is fixed to bushing 80 and projects through a slot 86 in shaft 82 to permit relative axial movement between them. Shaft 82 projects through an oil seal 87 and a thrust bearing 88, the thrust bearing being located axially in one direction by a retaining ring 90. Shaft 82 continues upwardly freely through metering valve 70, through a governor assembly 91, and into cover portion 20 through a journal bearing 92. The bearing is inserted in an aperture in a partition 93 in housing portion 18. The upper end of shaft 82 has a slotted pivotal connection at 94 to a lever 95 that is fixed to a rotatably mounted rod 96 forming a part of the vehicle accelerator pedal linkage.

Thrust bearing 88 and metering valve 70 are axially separated by an idle speed control spring 97 that surrounds shaft 82. The spring is seated at one end in a recess 98 in valve land 74 and at the other end against thrust bearing 88. The spring exerts a predetermined upward preload on land 74. The upper end of valve 70 is also recessed, and is slidably (see FIGURE 3) splined to a reduced diameter sleeve member 100. The sleeve member is fixed to the lower race 102 of a thrust bearing 104 that slidably surrounds shaft 82.

Sleeve member has a cam follower slot 106 in which slides a drive pin 108 that is fixed to shaft 82. Slot 106 has an axially extending portion 110 and an inclined portion 112. Axial portion 110 permits relative axial movement between metering valve 70 and shaft 82, while inclined portion 112 forces the metering valve to rotate relative to shaft 82 when the valve is moved axially. A second compression spring 114 surrounds shaft 82, and is seated between the lower end of sleeve member 100 and the bottom of recess 115 in upper land 72.

The thrust bearing 104, sleeve member 100, and valve 70 are moved axially downwardly by the mechanical flyweight governor assembly 91. This latter mechanism includes a cage or base plate 118 nonrotatably keyed to shaft 82. The cage has pairs of laterally spaced arms or ears 120, between which are pivotally mounted a pair of right angled speed responsive members 122. The lower portion of each member 122 is formed as a weight 124, while the upper portion constitutes a lever 125 that abuts the upper race of bearing 104. Suitable screw adjusting devices 126 provide adjustment in a known manner. The governor operates to depress sleeve valve 70 downwardly relative to shaft 82 against the forces of springs 97 and 114 upon outward movement of weights 124 under the effect of centrifugal force, in a manner that will become clearer later.

The preload of spring 114 maintains sleeve member 100 and metering valve 70 in their axially-most separated positions shown in FIGURES 2 and 3 below a predetermined speed of rotation of shaft 82 of, say, 2400 r.p.m., for example; that is, below the speed at which injection advance is desired, as will be explained more fully later.

Above 2400 r.p.m., centrifugal force acting on the governor weights overcomes the preload of spring 114, and permits movement of sleeve 100 into the end of valve land 72.

Lubrication of the various parts is as follows: The accelerator pedal linkage and governor mechanism, as well as the upper portion of metering valve 70, are lubricated by fuel sprayed into the upper housing portion chamber by means of a non-return lubricating jet assembly indicated at 127. The pump drive plate thrust and side bearings 40 and 33, and plungers 50, are lubricated by engine oil supplied through suitable intersecting passages 4 leading to these parts.

The accelerator pedal control linkage is illustrated schematically in FIGURE 3. It includes an accelerator pedal 128 pivotally mounted at 129, and pivotally connected near its center to an articulated linkage consisting of links 130 and 131. These links are pivoted to each other, the opposite end of link 131 being fixed to rod 96 in FIGURE 2. Suitable wide open throttle and idle stops 132 and 133 are provided, as shown. A return spring 134 normally biases the pedal 128 to its idle position.

To prevent afterrunning of the engine when the ignition is shut off, and to prevent overspeeding when desired, an additional external fuel shut-off linkage is provided. This consists of a power or manually movable knob 135 secured by a horizontally movable link 136 to a fuel shut-off lever 137. The lever, in its simplest form, is fixed for rotation with rod 96 in FIGURE 3, and rotates between fuel shutoff and wide-open throttle positions, as indicated. The fuel shut-off position would move the metering helix downwardly to a position completely opening spill ports 58 so that no fuel would be discharged through passages 56.

Operation FIGURE 2 shows the parts in the curb-stop or non running position. The idle speed and injection advance springs 97 and 114 preload metering valve 70, sleeve member 100, and the governor weights 124 to the positions shown. The accelerator pedal 128 (FIGURE 3) is released to its idle position; therefore, no upward force is exerted on shaft 82 by this linkage. The metering helix 78 is positioned relative to the spill holes 58 at the point indicated in FIGURE 3A so that slightly more than the normal amount of fuel required to provide idle operation of the engine would be injected past the delivery valves if the fuel pump were to be driven at this time. Consequently, the auxiliary fuel control shut-off knob 135 (FIG- URE 3) would be moved to the left to move shaft 82 and valve 70 downwardly to a fuel shut-off position locating the spill holes 58 relative to helix 78 so that all of the fuel will spill back into chamber 60.

To start the engine, an amount of fuel far greater than the normal fuel load dispersion is desirable. The accelerator pedal is depressed fully to its wide-open throttle position, which also corresponds to the prime-start position. This full depression of the pedal rotates lever 95 clockwise to move shaft 82, governor mechanism 91, and metering valve 70 upwardly so that the bottom portion of the metering helix 78 now closes off spill holes 58 for almost the entire rotation of the metering valve as indicated in FIGURE 3A. 0nce the engine is cranked, therefore, substantially the entire output from the pump plunger bores 68 will be forced into discharge passages 56.

As soon as the engine is started, the operator releases the accelerator pedal to its idle or rest position. This again returns shaft 82 downwardly towardsits original curb-stop position, which schedules fuel discharge at a volume that will be greater than that needed to provide a selected engine idle speed of say, 575 r.p.m. Simultaneously, however, the rotation of governor 91 at shaft speed now moves metering valve 70 further downwardly, and relative to shaft 82, against the force of spring 97 toward the idle speed position indicated in 3A. The preload of spring 97 is chosen such that below a predetermined lower idle limit r.p.m., such as 400 r.p.m., for example, it will prevent the governor from moving. Between the idle speed limits of, say, 400-900 r.p.m., for example, the opposing forces provided by spring 97 and the downward movement of metering valve 70 due to centrifugal force acting on the governor will cause the metering valve to reciprocate back and forth until it reaches an equilibrium position at the idle speed location chosen.

If the accelerator pedal is now again depressed shaft 82 is raised, metering helix now covers more of the area of spill holes 58, and the shaft speed increases. When the shaft speed reaches the upper idle speed limit of 900 r.p.m., the metering helix 78 will have been moved downwardly by the governor enough to contact a stop 99 on thrust bearing 88. This now renders the governor 91 inoperative above 900 r.p.m. to provide any further downward relative movement of sleeve 70 with respect to drive shaft 82 so long as the preload of spring 114 remains in effect. As stated previously, this preload is operative to maintain land 72 and sleeve 100 in the relative positions shown below a speed of 2400 r.p.m.

At 900 r.p.m., drive pin 108 will be positioned in the slot 106 of sleeve 100 at the junction between portions 110 and 112. Further change in the axial position of metering helix 78 between 900 and 2400 r.p.m. is now, therefore, controlled entirely as a function of the movements of accelerator pedal 128. That is, depression of the pedal will rotate lever clockwise to raise shaft 82, governor mechanism 91, and sleeve valve 70 proportionally. Load control is now a direct function of accelerator pedal position.

Above 2400 r.p.m., centrifugal force acting on governor weights 124 now is sufficient to overcome the preload of spring 114 and begin moving sleeve into the upper end of sleeve valve 70, and downwardly relative to drive shaft 82. Since pin 108 must follow the curve of slot portion 112, the sleeve valve now is forced to rotate as well as move axially. This provides a change in the injection timing; that is, the helix 78 advances or rotates ahead relative to shaft 82 so that the fuel is now injected earlier. At a given speed of, say, 3400 r.p.m., pin 108 will have moved to the end of inclined slot portion 112, and further axial and circumferential movement of the sleeve valve relative to shaft 82 will terminate.

Deceleration control is obtained by releasing the accelerator pedal to its idle position. Shaft 82,. the governor assembly 91, and helix 78 immediately move downwardly, and decrease the fuel output. Since the governor is operative, the high centrifugal force still acting on the governor weights at first maintains spring 114 compressed, and sleeve 100 almost entirely within land 72. However, as the speed decreases, the force of spring 114 will move valve 70 downwardly, so that at 2400 r.p.m., spring 114 will have moved valve 70 to its downwardmost position relative to shaft 82, and valve 70 will be in its downwardmost position against stop 99. The helix 78 will now completely uncover the area of spill holes 58, and thereby shut off all fuel flow to the nozzles. When the speed falls within the 400900 r.p.m. idle speed range, spring 97 and the governor will again be operative to move the sleeve valve 70 and metering helix 78 to the idle speed position.

FIGURES 4, 5 and 6 show an additional control that can be added to the FIGURE 2 construction to provide proper fuel flow when injection advance is called for. It is substituted for the thrust bearing 88 in FIGURE 2.

As shown in FIGURE 4, the lower end of valve land 74 has two (only one shown) slots 138 that receive elongated vertical tabs 139. The tabs are fixed to the upper portion 140 of a thrust washer assembly that is separated from a lower portion 141 by four spaced balls 142. The balls are retained in upper portion 140 in four sockets 143. The lower portion 141 contains four circumferentially extending grooves 144 in which the balls are received, the grooves tapering in a circumferential direction to form inclined cam surfaces. A ring 146 locates the assembly in one axial direction, with a washer 148 between the ring and lower bearing portion. The lower portion is fixed to drive shaft 82.

The engine normally schedules fuel flow for injection into the engine cylinder at a certain rate. The plotted curve of changes in injection velocity versus degrees of shaft rotation between bottom and top dead center positions of the pump plungers has a sinusoidal shape. To provide a substantially constant injection rate, injection usually occurs over only the nearly flat portion of the curve. If, however, injection advance is called for, as in the FIGURE 2 embodiment when the speed exceeds 2400 r.p.m., the injection beginning occurs over an earlier lower portion of the curve, and ends earlier, thus resulting in a lower total delivery volume of fuel. The modified thrust washer of FIGURES 4-6 compensates for this by raising the metering helix 78 of FIGURE 2 to a higher delivery position at the same time that it is rotated relative to drive shaft 82 during the speed sensitive injection advance timing operation. The use of this torque control device thus permits a wider injection advance range with good matching of the full-load fuel flow curve to engine requirements.

More specifically, in operation, and considering FIG- URES 2 and 6, when the speed is such that valve has bottomed against stop 99, and slot portion 112 of sleeve starts downwardly on drive pin 108, the rotation of valve 70 relative to shaft 82 causes upper thrust washer portion to rotate relative to lower portion 141 (the upper portion being keyed to the valve, and the lower portion being fixed to shaft 82). As a result, balls 142 ride up ramps 144 and cause upper portion 140 to move upwardly. This raises helix 78 to a position closing off more of the area of spill ports 58. A greater volume of fuel flow then occurs for this advanced position of the helix as compared to that volume that would normally be delivered without the raising of the helix.

FIGURES 7 and 8 show a slightly different embodiment of the invention. The lower pump drive portion of FIGURE 7 is identical to that shown and described in I connection with the FIGURE 2- embodiment, and the details thereof, therefore, are not repeated. The differences lie primarily in the construction of the governor mechanism and its limited interconnection with drive shaft 82 to provide the relative axial and rotational movements of the metering helix 78 with respect to the drive shaft. In the case of FIGURE 7, the governor is a horizontal tension spring type; that is, the FIGURE 2 embodiment shows vertical idle speed control and injection timing advance springs 97 and 114. In FIGURE 7, these springs are positioned horizontally and cooperate in a slightly different manner.

As shown in detail in FIGURES 7 through 12, the governor has a cage consisting of a plate integral with a central tubular sleeve 152 that is pinned or keyed to drive shaft 82'. The cage has four apertured upturned ears 154 at its edges, with a pivot pin 155 rotatably mounted between each pair of cars for rotatably supporting weights 156. The cage has two central apertures 158, one of which receives the end of an upturned flange formed integral with a ring member 162. The ring member is rotatably mounted on the upper end of sleeve valve 70', and is held against axial relative movement by a retaining ring, not shown.

Also formed integral with and extending at right angles to mounting plate 162 is a bracket 163. The bracket has a pair of oppositely disposed inclined cam slots 164 each receiving a pin or roller 165 fixed to one of the governor Weights. Due to the shape of the cam slots, as the weights move arcuately, ring member 162 and sleeve valve 70 will move up or down, as the cause may be, to cause metering helix 78' to move axially to control spill holes 58'.

Also mounted on the upper end of the sleeve valve is a disc-like member 166 that is non-rotatably fixed to the sleeve valve by tangs 167, and has an upstanding flange 168. The flange has a horizontally elongated speed advance slot 170 that slidably receives the bent end 172. of a speed advance lever 174. The lever 174 is pivotally and adjustably mounted on the upper part of weight 156. A driving connection is provided between shaft 82 and sleeve valve 70 by abutment of the edge of flange 168 against the edge of a projecting drive flange portion 176 on governor cage member 150.

A horizontally disposed preloaded idle speed tension spring 178 has opposite ends wrapped around a pair of pins 180 provided on opposite weight members 156. The spring initially biases the weight members together below a drive shaft speed of approximately 400 r.p.m. A screw adjusting device is provided between one end of the spring and one anchor pin.

A preloaded speed injection advance spring 182 has its looped ends secured around a second pair of pins 183 at the bottom of weight members 156. The loose eyelet end corrections of the speed advance spring, in this instance, permit initial outward movement of the weights to a position comparable to high idle speed operating position (900 r.p.m.) before the preload has any effect. Between 900 r.p.m. and approximately 2400 r.p.m., the preload is sufficient to maintain the governor weights in the diagonally outward position so that the governor is ineffective during this speed range to further influence the axial position of sleeve valve 70. At 2400 r.p.m., lever 172 (FIGURE 12) will have moved to the right to the end of slot 170, preparatory to the speed advance injection phase of operation. Above 2400 r.p.m., the centrifugal force on the governor weights overcomes the spring preload, and the weights then move further outwardly. This causes lever 172 (FIGURE 12) to bear against the end of slot 170 and rotate flange 168, and therefore, the sleeve valve 70, relative to shaft 82'. This advances the injection of the fuel in the same manner as described in connection with the FIGURE 2 embodiment.

The governor also includes two weight stop members 184 (FIGURE 7) that prevent unlimited outward movement of the weights. The stop members have lost motion slots 186 at each end that cooperate with anchor pins 188 fixed to the top end of each weight.

Additionally, to prevent unsymmetrical governor motion due to slight manufacturing differences in the governor weights, an equalizer bar 190 is provided. It is pivotally connected at opposite ends to the two weights 156 above and below the pivot pins 155. 192 is a timing indicator fixed to speed advance lever 168. It cooperates with a scale in window 12 of FIGURE 1 to coordinate the injection advance to engine operation. An additional indicator 194 is provided to coordinate the rise of shaft 82 with accelerator pedal position.

In operation, the governor provides the same control over the spill holes 58 as provided by the FIGURE 2 embodiment. As seen in FIGURES 7 and 8, however, the components for providing the axial and rotational movements of the sleeve valve 70 relative to drive shaft 82 are separated; that is, instead of the single slot 106 in FIGURE 2, FIGURE 7 provides the lost motion connection 170 and 172 for the injection advance rotation, and the cam and cam follower slot connections 164, 165 for first the axial relative movement in the idle speed range, and subsequently the axial relative movement simul- 9 taneous with the rotative relative movement, during the speed injection advance stage. 7

It will be clear, therefore, that the deceleration, prime start, idle, normal, fuel shut-off, and overspe ed operations are substantially the same as those described in connection with the 'FIGURE 2 construction; they, therefore, are not repeated.

FIGURES 13-16 illustrate several different delivery or retraction valves that can be used with the injection pump embodiments of FIGURES 2 and 7 to control the discharge of fuel from the pump plunger barrels andbackflow from the nozzles; Retraction valves serve two purposes. One is to act as a check valve to prevent leakage from the high pressure sectionat the nozzle to the low pressure section at the pump plunger barrel. A second purpose is to help lower the pressure in the line' to the nozzle by piston suction action of the valve as it seats to prevent nozzle dripping or secondary injection.

FIGURE 13 illustrates one type of delivery valve that can be used. This valve is shown installed in FIGURE 7 in the discharge line 58 on the right side. The valve body is part of pump housing portion 26'. As seen in FIGURES 7 and 13, the delivery valve assembly includes a slidable retraction valve 200 that issealingly mounted in a first bore 202 in the valve body. The bore has an enlarged portion 204 at one end that is connected to the barrel of the pump plungers 68 by a port 58 of reduced diameter. The shoulder 206, formed at the connection between bore 204 and port 58, serves as an end stop for the valve. The opposite end of bore 202 is connected by a tapered conical seat 208 to a bore 210 that threadedly receives a tubular insert 212. The hollow interior of the insert connects with a right angled fluid discharge passage 214. The wall of passage 214 serves as a seat for a compression. spring 216 that bears against a ball valve member 218 to bias it into engagement with conical seat 208 to block back-flow of fuel to pump plunger barrel 68 from the fuel injection nozzles (not shown) connected to passage 214.

The retraction valve 200 is of the spool type having an elongated first land 220 connected to a land 222 by a neck portion 224 of reduced diameter. The fluid annulus 226 defined between the lands is connected to bore 204 by a cross-bore 228 and a central bore 230. The left-hand portion of bore 230 receives an insert 234 that serves as a guide for a light helper spring 236. The helper spring is used merely to maintain the retraction valve in contact with ball 218.

The operation of fuel injector nozzles is known. The nozzle generally has a set opening pressure below which no fuel is admitted through the nozzle. Once the nozzle opens, and a predetermined quantity of fuel has been ejected, the pressure drops and the nozzle closes. The residual pressure in the nozzle line is then substantially the same as the opening pressure, unless retraction valves are used. The known delivery valves generally operate on a retraction principle; that is, the principle of retracting a finite volume of fuel during the suction stroke of the pump plunger to reduce the residual pressure in the line between the delivery valve and injection nozzle so that secondary injection of fuel will not occur. The valve constructions proposed in FIGURES 13-16 also operate on this principle.

In operation, and referring to FIGURES 7 and 13, once the lines between each of the delivery valves and fuel nozzles have been filled with fuel, and the pump has moved on its upstroke to raise the pressure in the plunger barrels 68 above the force of spring 216 and the residual pressure of the fuel in line 214, the fuel pressure acting in bore 204 will move retraction valve 200 to the right to unseat ball valve 218. The retraction valve will continue to move to the right until the valve annulus 226 is open to communication with chamber 238 and passage 2.14. A finite quantity of fuel will then pass from bore 204 into chamber 238 and out through passage 214.

As soon as the pump plungers have completed their 10 compression stroke and begun their downward suction movement, the pressure of fuel behind retraction valve 200 in bore 204 will immediately decay. This decay now permits the force of spring 216 and the residual pressure of the fuel in chamber 238 to cause ball valve 218 to move toward its seat 208, which also moves valve 220 back into bore 202. When the left edge 240 of land 222 of the valve reaches the left edge of conical seat 208, the retraction valve will seal off further back flow of fuel from chamber 238 into pump plunger barrels 68 through bores 28 and 230 of the valve. At this time, therefore, the pressure in chamber 238 is substantially the same as the nozzle closing pressure.

The force of spring 216 and the residual pressure in chamber 238, however, continue to move ball 218 leftwardly until it seats against conical surface 208. In doing so, the ball 218 has now moved land 222 of retraction valve 200 out of chamber 238 and into bore 202 sufficiently so that a finite amount of fuel has also been retracted into bore 202 between the right-hand edge 242 of land 222, ball 218, and the edge of conical valve seat 208. Thus, the effective volume of chamber 238 has been increased, and, since the quantity of fuel between the injection nozzle and land 222 became fixed when edge 240 entered bore 202, the residual pressure of the fuel in chamber 238 has been lowered. The lower residual pressure thus prevents secondary injection.

FIGURES 14-16 show other types of delivery valves that are similar to that shown in FIGURE 13. The construction shown in FIGURE 14 is shown installed in the injection pump assembly of FIGURE 7 of the left-hand side. FIGURE 14 shows a one-piece valve that seats at the bottom of the delivery valve bore instead of at the top as shown in FIGURE 13. In FIGURE 14, the left-hand portion of retractor valve 200' is provided with a conical face 250 that has an interference fit with a conical seat 252 provided at the point of juncture between the bore 204' and the discharge passage 58. The connection between bore 204' and the annular fluid chamber 226 is by a diagonal bore 254. Also, the upper end of retraction valve 200 has a spring guide stem 256.

The FIGURE 14 valve operates over-all in substantially the same manner as the valve shown in FIGURE 13. The compression stroke of the pump plungers delivers fuel at a pressure sufficient to unseat retraction valve 200' and move it to the right until land 222' is moved out into chamber 238, thereby permitting fuel flow from the pump plunger barrel 68 through bore 254 into chamber 238. When the pressure drops in bore 204' as a result of the suction stroke of the pump plungers, the spring 216' and residual fuel pressure acting against the upper part of the retraction valve move it to the left until land 222' just enters the bore 202'. Further movement of the valve retracts a finite volume of fuel into the bore until face 250 seats, thus lowering the residual pressure in the fuel nozzle line by the desired amount.

The embodiment shown in FIGURE 15 again consists of a two-piece delivery valve including a ball 260 and the retraction valve 200" that are similar to the parts shown in FIGURE 13, but located at opposite portions of bore 202". In FIGURE 15, the ball seats against a conical surface 262 provided between passage 58" and bore 204". The fuel is connected from bore 204" to annulus 226" by a diagonal bore 264. The construction of FIGURE 15 operates in substantially the same manner as that described in connection with the FIGURE 14 showing.

FIGURE 16 illustrates a simplified version of the FIG- URE 15 construction. The ball valve 260" seats against the pointed edge 270 between passage 58" and bore 204". This eliminates the precise requirements for the conical seat 262 shown in FIGURE 15. It also relieves the problem of concentricity of the valve and ball.

From the foregoing, it will be seen that the invention provides a simplified construction of a fuel injection assembly, and yet one that has all of the necessary control functions for properly scheduling fuel to an internal combustion engine during the entire speed and load range of operation. It will also be seen that the fuel injection pump assembly is usea'ble with various simplified delivery or retraction valve constructions, each of which operates to deliver a finite quantity of fuel to the injection nozzles while also retracting a finite volume of fuel to prevent secondary injection.

While the invention has been shown in its preferred embodiments in the figures, it will be clear to those skilled in the arts to which the invention pertains that many changes and modifications may be made thereto without departing from the scope of the invention.

We claim:

1. A mechanical governor assembly comprising, a drive shaft, a sleeve shaft rotatably and axially slidably surrounding said drive shaft, speed responsive means secured to and driven by said drive shaft and abutting said sleeve shaft for moving it axially, and control means operably connecting said shafts for effecting concurrent relative axial and rotational movements therebetween upon rotation of said drive shaft at predetermined speeds, said control means including an inclined cam slot secured for rotation with said sleeve shaft, said speed re- 12 sponsive means including fiyweight members movable substantially laterally from said shafts upon increase in speed of rotation thereof, a cam secured to said weight members and engageable in said slot to provide axial relative movement between said shafts upon changes in the speed of rotation thereof, said control means also including lost motion means comprising a substantially circumferential slot in a portion of one of said shafts, a pin operably secured to and movable with said weight members, said pin being freely movable in said slot below predetermined shaft speeds and engageable with said portion above predetermined shaft speeds to effect relative rotation between said shafts.

References Cited UNITED STATES PATENTS 366,228 7/1887 Lynn et a1. 73534 X 809,560 1/1906 Graham et al 73534 X 1,089,256 3/1914 Pardee 73-534 X 1,108,739 8/1914 Gassmann 73-534 X 2,272,726 2/1942 Sanders l23-140 2,899,810 8/1959 Pierce 64-25 3,062,027 11/ 1962 Pigeroulet.

JAMES J. GILL, Primary Examiner.

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