CA1151961A - Engine governor with reference position for throttle limiter - Google Patents
Engine governor with reference position for throttle limiterInfo
- Publication number
- CA1151961A CA1151961A CA000350698A CA350698A CA1151961A CA 1151961 A CA1151961 A CA 1151961A CA 000350698 A CA000350698 A CA 000350698A CA 350698 A CA350698 A CA 350698A CA 1151961 A CA1151961 A CA 1151961A
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- CA
- Canada
- Prior art keywords
- speed
- engine
- throttle
- overriding
- governor
- Prior art date
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- Expired
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Abstract
Abstract of the Invention An engine governor having overriding means for limiting the flow of fuel to an engine, means for moving the overriding means to an intermediate reference position upon actuation of the governor, and means for moving the overriding means from the reference position to other positions for limiting the flow of fuel to that suitable for operating the engine at speeds close to a set speed. Means for actuating the governor before the engine reaches the set speed, means for moving the overriding means from the reference position to the other limiting positions at a very slow rate, and means for moving the overriding means toward limiting the fuel flow to a minimum when an over-running load causes the engine speed to run a predetermined amount above the set speed. Such an engine governor combined with a load speed governor for independently governing the engine to a speed safe therefor, and to a lower speed safe for the load.
Description
196i Background of the Invention .__ The background of englne yovernors in general, and a full disclosure of my previous invention in combined engine and load speed governors, is contained in my U.S. Patent No. 4,1~1,103 issued on January 1~ 19~0. ~ly aforesaid engine governor was of a dyna-mically-surging type which allowed engine speed to oscillate rather rapidly (and forcefully for a vehicle in a lower gear ratio) about its predetermined limit.
While such oscillations are not damaging to the engine and may be helpful in encouraging a truck driver to "get out" of a lower gear ratio and into a higher ratio where the engine will be operating more efficiently, it is also advantageous to have an engine governor which allows the engine to be accelerated to its predetermined speed limit with less overshoot beyond that limit than provided by my previous dynamically-surging governor, and which will thereafter bring the engine quickly to run in clcse approximation to the predetermined speed limit, wandering from it only perhaps 1~ when in a very low gear and less in higher gears, and that probably not on any cyclical basis. Such action is obtained basically by positioning the engine throttle to a pre-determined reference position upon acceleration of the engine to a predetermined speed and actuation of the engine governor there-by, rather than by driving the throttle toward a full-closed position as ir. my previous patent application aforesaid.
Such a smooth and gentle control is advantageous for full economy, and for driver and/or passenger comfort, especially for an application such as a school bus engine, and is typical of my present invention which provides such an engine speed governor and also combines it with a load speed governor essen-tially like that of my aforesaid patent. ~he ~.ti~.~6~
present combination functions to safely control engine and load speeds generally like the combination of my aforesaid patent application, except smoothly, without the previously-experienced dynamic-surging in engine speed control mode. The present in-vention includes an overspeed control which acts to close the throttle beyond the reference position toward a completely closed position in the event of prolonged speeding outside a normal range above the predetermined speed limit (as would be possible for a driver proceeding downhill with the accelerator pedal "floored" or calling for maximum throttle opening), thereby retaining generally the feature of my previous invention which acted to close the throttle toward a completely closed position whenever the engine speed remained anywhere above the predeter-mined limit.
Like my previous invention, the apparatus of the pre-sent invention is a standard unit which may be connected to the standard carburetor, ignition system, and speedometer cable of any engine and vehicle, so that it may be applied at the factory or in the field without inconvenience, and spare parts for this apparatus will be the same for any engine-vehicle combination.
However, my present invention also contemplates the use of a lost-motion type overriding carburetor linkage (in place of the equally useable linkage-lengthening capsule disclosed in my aforesaid patent application) which gives a more conventional feel to the accelerator pedal, but with a more complicated parts situation, since each different engine-carburetor com-bination may require different linkage parts and adaptations.
Also, use of a conventional pulse generator connected to the tachometer drive of a Diesel engine is contemplated for appli-cation of the apparatus of the present invention thereto.
6~
Summary of the Invention In an engine governor for limiting the speed of an engine to a set speed and having movable overriding means for limiting the flow of energy-supplying means to the engine, the improvement including means for selectively moving the overriding means for suitably limiting the flow at rates of moving whereby the speed of the engine in unloaded condition follows the moving of the overriding means with only insignificant overrunning of the set speed upon cessation of the moving of the overriding means. The governor may have means for moving the overriding means in flow limiting direction to a predeterminted reference position upon actuation of the governor. The governor of the present invention may also have means for moving the overriding means from the reference position to suitable other positions for limiting the flow to that for operating the engine at speeds in close proximity to the set speed.
The present governor may have means for actuating the governor when the engine is accelerated to a predetermined speed, such as the set speed, and the means for moving the overriding means to suitable other positions may include means for moving the overriding means in a direction away from the reference position and opposite to its limiting direction upon its arrival thereat. Means for causing continuing moving of the overriding means in the aforesaid opposite direction when the engine is operating at speeds below the set speed may be included also.
Preferably, the present governor may be actuated at a predetermined speed which is slower than -the set speed, and may have means for causing the overriding means to move back in limiting direction to the reference position, after its moving away from the reference position in opposite direction to the limiting direction, when the engine is operating at speeds at and above the set speed. The governor may also have means for respec-tively continuing the aforesaid moving away from and to the refer-ence position while the engine is operating at speeds at, and ~ith-in a predetermined range above, the set speed. The means for moving the overriding means to other positions may include means for causing the moving thereto to occur at a substantially slower rate than the moving of the overriding means in the flow limiting direction upon actuation of the governor, and such slower moving may be only in the direction opposite to the limiting direction.
In the preferred embodiment, the present governor has means for monitoring the speed of the engine for detecting an acceleration thereof to a predetermined speed which is slower than the set speed from another lower predetermined speed within a predetermined time period, and for actuating the governor upon detection of such an acceleration. Means is also provided in a preferred embodiment having the repetitive moving away from and to the reference position for causing the overriding means to cease said repetitive moving when the engine is accelerated to operate at a speed exceeding the aforesaid predetermined range, and to move past the reference position in limiting direction for decelerating the engine to operate at a speed within the pre-determined range. Means is also provided to cause the cessation of said repetitive moving and to cause the overriding means to move away from the reference position in a direction opposite to the limiting direction upon subsequent operation of the engine at a speed below the set speed. The preferred embodiment is an engine speed governor and load speed governor combination for an engine and load connected by a multi-ratio transmission and having a driver-operated means for controlling the flow of energy-supplying means to the engine, overriding means for limiting that flow, means for selectively operating the overriding means in flow limiting direction and opposite thereto, high engine speed responsive means for independently causing the operating means to operate in the limiting direction, high load speed responsive means for indepen-dently causing the operating means to operate in the limiting direction, and low engine speed responsive means and low load speed responsive means for jointly causing the operating means to operate the overriding means in the direction opposite to the limiting direction when concurrently responsive, this combination being characterized further by the foregoing improvements as described in this summary taken alternatively or in combination as desired.
Brief Description of the Drawings Fig. 1 is a diagrammatic view showing the engine and load speed governor of the present invention connected to a trans-missionl carburetor linkage, and accelerator pedal of an engine connected to vehicle wheels by the transmission;
Fig. 2 is a diagrammatic view showing mechanical details of the governor proper;
Fig. 3 shows the throttle lin~cage of Fig. 1 in a differ-ent configuration;
Fig. 4 shows the switch plate of the present governor as connected to the electronic control portion thereof;
Fig. 5 shows a schematic circuit diagram of an electro-nic control providing for positioning the throttle-limiting at a reference position;
Fig. 6 shows a schematic circuit diagram of the portion of an alternate electronic circuit providing slow motion of the throttle-limiting means in one direction; and Fig. 7 shows a schematic diagram of a portion o an electronic circuit providing slow motion of the throttle-limiting means as desired.
tion o~ the Preferred Embodiment In the illustrated preferred embodiment, as shown schematically in Fig. 1, an internal combustion engine 20 has connec~ed thereto a transmission 22 for drLving a load 24 such as the drive wheels of a truck. The transmission 22 is of the usual construction which allows automatic or manual shifting of the gears therein to provide various ratios of speeds between the engine 20 and the load 24. Typically, in a truck, the transmission 22 is shifted into "low gear" to start the load 24 moving at very low speeds, as from a standing start, so that the engine 20 can operate at a rotational speed of thousands of revolutions per minute, where it operates most efficiently, while the load 24 is eased into motion by a friction clutch or hydraulic connection (not shown) included in the transmission 22, and a very large torque is applied through the gearing of the transmission 22 ~-o the axle 26 of the drive wheels 28 of the load 24, it being understood that the engine 20 and the transmission 22 are attached to and part of the load 24. As the drive wheels 28 pick up speed, and before the engine 20 reaches some safe limit to its short term rotational speed, such as 4,400 rpm for example, it is desirable to shift the transmission 22 into a "higher gear" ratio where the wheels 28 will turn at a higher rpm relative to the engine 20, and the power of the engine 20 will be applied through the transmission 22 to the wheels 28 to farther accelerate their speed until the engine 20 again approaches its safe rotational speed. This process of accelerating the engine 20 toward its maximum speed and shifting into a "higher gear" continues until the wheels 28 are driving the load or truck 24 along at a safe and suitable road speed, at which time the transmission will be in its nominal "high gear", the load or truck 24 may be running along at 50 miles per hour, and the engine 20 may be revolving at 3,000 rpm.
It is desirable that the road speed of the load 24 should be controlled or governed to some safe speed such as 55 miles per hour and it is also desirable that the speed of the engine 20 be governed or controlled to its maximum safe speed for long term operation, such as a speed of 4000 rpm, and the engine and load speed governor 30 of the illustrated embodiment of this invention has overriding means for limiting the flow of the energy-supplying means or fuel to the engine to automatically and selectively con-trol both speeds with peculiar advantages to each.
The governor 30 is shown schematically in Fig. 1 connec-ted to the load side of the transmission 22 by the flexible rotary cable 31, which may be the typical "speedometer cable", and which transmits rotary motion at a speed proportional to the speed of the wheels 28. A gear 32 connected to the cable 31 inside the housing 33 drives an output gear 34 which is connected to a speedometer cable C for driving a speedometer S which may be located on the dashboard of the truck cab. Governor 30 is connected to the carburetor throttle plate 35 of the carburetor 36 of the engine 20 by a flexible pull cable 38 enclosed within a flexible sheath 40 of fixed length attached to and extended from the governor 30, as shown in Figs. 1 and 2. The connection between throttle plate 35 and cable 38 is by means of the throttle arm 42 mounted on throttle shaft 44 to which the throttle plate 35 is affixed, and a stud 46 fixed in the free end 48 of the throttle arm ~2 intermediately thereof forms a mounting point for a pivotable eye fitting 50 which is permanently attached to the free end of the cable 38.
The extended end of the flexible shea-th 40 is attached to a bracket 52 mounted to the carburetor 36 for holding the end of the sheath 40 in general alignment with the stud 46 and the eye fitting 50 on the extending end of the cable 38. A first tension spring 54 is stretched between a first pin 56 installed near the extremity of the free end 48 of the throttle arm 42 and a second pin 58 is fixed in relation to the carburetor 36 for hold-ing the throttle plate 35 in its normally nominally closed or idle position as shown in Fig. 1 in solid lines. An accelerator arm 60 is mounted for free rotation on the throttle shaft 44 and is connected to the throttle arm 42 by a second extension spring 62 stretched between a third pin 64 and a fourth pin 66, the pins being respectively fixed in the free ends of the arms 42 and 60.
The spring 62 is substantially stronger than the spring 54. A
stop 68 on an extending portion 70 of the accelerator arm 60 is biased against the throttle arm 42 by the spring 62 under normal idling conditions for the engine 20.
An accelerator pedal 72 is normally biased to an idle position against a pedal stop 74 by a third extension spring 76 of suitable strength and is suitably freely pivoted on a pedal shaft 78 for pedal actuation to a full or wide open throttle position (indicated by the numeral 72') against a floorboard stop 80. The lower end of the pedal 72 is connected to a fifth pin 82 mounted on the free end of the accelerator arm 60 by a link 84 pivotable at the pedal 72 and the pin 82. The link 84 is of suit-ably adjusted length to place the pedal 72, the accelerator arm 60, and the throttle arm 42 simultaneously in their respective normal or idle positions as shown in solid lines in Fig. 1.
When the governor 30 is in its normal or unactuated condition, the cable 38 may be freely pulled out from its sheath ;~5~
40 by pivoting the throttle arm 42 counter-clockwise against the bias of the spring 54. sy depressing the pedal 72 against stop 80 to its wide open position, the accelerator arm 60 will be rotated counterclockwise -to its wide open throttle position as shown in broken lines and indicated by the numeral 60' in Fig. l;
and the spring 62 will pull the throttle arm 42 to its wide open throttle position as shown in broken lines and indicated by the numeral 42'.
When the governor 30 has been actuated as described hereinafter, and the eye fitting S0 at the extending end of the cable 38 has been pulled back toward its normal or idle position as shown in solid lines, the counter-clockwise movement of the throttle arm 42 will be limited accordingly, and the spring 62 will be stretched as necessary to accommodate any mismatch between the position of the pedal 72 and the position of the throttle arm 42~ The extreme mismatch, as shown in Fig. 3, occurs when the pedal 72 is at the wide open throttle position and the throttle arm 42 has been limited to its idle position by withdrawal move-ment of the cable 38, the spring 62 is at its maximum stretched condition, and the cable 38 extending from the governor 30 is thereby fully overriding the call from the accelerator pedal 72 for full throttle. Intermediate positions of the pedal 72 and the arm 60 are available at the will of the operator, as are intermediate positions of the throttle arm 42 as permitted by the limiting action of the cable 38.
The pedal 72 is thereby free to be positioned wherever the operator desires, and so long as the governor cable 38 is in its fully extended, normal, non-limiting position, the accelerator arm 60 and the throttle arm 42 will be biased together by the spring 62 to move as one, and the throttle plate 34 will open and close according to the position of the pedal 72. If the cable is retracted to limit the throttle opening, the spring 62 will stretch as necessary upon depression of the pedal 72 so that the accelerator pedal will have a generally normal feel just as a conventional accelerator pedal and throttle linkage. The accelera-tor pedal and throttle and carburetor linkage disclosed is schematic and representative of infinite mechanically equivalent variations to suit particular engine-carburetor-vehicle combina-tions. Particularly, torsion springs may be substituted for the tension springs disclosed, for space and configuration considera-tions, and a similar apparatus could be adapted for use with the control lever of a Diesel or gasoline fuel injection system, or other means of limiting the flow of energy-supplying means to a motor or engine, even an electric one.
The construction and operation of the load speed gover-nor portion 86 of the present invention as shown in Fig. 2 is generally the same as that disclosed in my aforesaid patent appli-cation, and no further disclosure is needed herein except to point out the additional elements incorporated therewith as shown ir Figs. 2 and 4 to provide means for moving the carrier 88 to a pre-determined reference position upon actuation of the engine speed governor portion 90 of the engine and load speed governor 30:
An arcuate switch plate 92 is mounted to pivot for adjust-ment about the carrier shaft 94 which is affixed to the housing 33 by means of a bracket 96 attached inside the housing. The plate 92 is formed of insulating material and is mounted on a metal hub 98 which is mounted for pivoting on the shaft 94. The hub 98 has an attachment flange 100 to which the plate 92 is fastened by rivets 102. The plate 92 is located directly behind the carrier 88 within the housing 33, and the bracket 96 supports the shaft 94 between the carrier 88 and the hub 98. The shaft 94 and hub 98 mounted thereon extend rearwardly through an opening in the housing 33. Outside the housing 33 a crank arm 104 is attached to the hub 98 and has an extending end in which is mounted a pivotable stud 106 having a threaded cross hole into which is threaded an adjustment screw 108. The shank of the screw 108 at the head end thereof passes through a clearance hole in a stud 110 fastened to the outside of the housing 33, and a compression spring 112 mounted on the screw 108 between the studs 106 and 110 holds the two studs 106 and 110 biased firmly apart to a distance limited by the head 114 of the screw 108.
Thus, rotary adjustment of the screw 108 acts to change the distance between the studs 106 and 110, thereby pivoting the switch plate 92 about the shaft 94 to set the plate 92 at any desired position within a suitable range of adjustment. Such positioning is desirable in order to angularly place a reference position contact 116 as desired in relation to the carrier 88.
The contact 116 is mounted on the switch plate 92 in arcuate rela-tion to the hub 98, and is connected to an electrical lead 118 for connection to the electronic control portion 119 of the governor 30 as explained hereinafter. The contact 116 extends clockwise from a generally central portion of the arcuate shape of the plate 92, and a somewhat similar limiting contact 120 is mounted on the plate 92 spaced a small gap 122 counter-clockwise from the contact 116 and extending along the same arc as contact 116 in a counter-clockwise direction generally to the left side of the plate 92. The contact 120 is connected to an electrical lead 124 for connection to the electronic control portion 119.
An electrically conductive spring leaf 126 having a carrier electrical contact 128 at one end thereof is fastened at the other end to the rear side of the carrier 88 by rivets 130 and is sprung away from the carrier 88 for spring-biased contact with the switch plate 92 and the contacts 116 and 120 along the arcs thereof wherever the carrier 88 may be positioned as explained in my aforementioned patent application or to be explained herein-after. By its connection to the carrier 88, the contact 128 is a grounding contact so far as the electronic control portion of the governor is concerned. In Fig. 4 the carrier 88 has been broken away, and the spring leaf 126 and the contact 128 are shown in more detail in relation to the switch plate 92. The left, or counter-clockwise end of the reference position contact 116 forms the actual reference point or position to which the carrier contact 128 is moved and homed for establishing a reference position for the carrier 88 and thereby the overriding means for limiting the flow of energy-supplying means which is an object of the present nvention .
A reversible electric motor 132 is included in the electronic control 119, as are the accelerate or open throttle contact 134, the decelerate or close throttle contact 136, and the grounding contacts 138 which control the motor 132 at the command of the load speed governor 86 to turn the lead screw 140 which in turn causes the carrier 88 to move in rotation on the shaft 94.
In simplest terms, the governor 30 of the present inven-tion functions as follows: In the absence of a signal to the contrary, either from the load speed governor 86 or the engine speed governor 90, the load speed governor 86 acts to move the carrier 88 to its extreme counter-clockwise, rest, or wide-open-throttle position as shown in Fig. 2, where the flow of fuel or energy~supplying means to the engine 20 is not limited at all by the governor 30, but is dependent upon the operator-positioned accelerator and throttle linkages as described hereinbefore and in my aforementioned prior patent application. Then, in the absence of a load speed sufficient to actuate the load speed gover-~ ~.
,, r~ nor 86 as described in my aEoresaid patent _~p~Le~on (e.g. whenthe transmission 22 is in neutral, or in a lower gear ratio whexe the engine must reach a speed far above the governed speed in order to actuate the load speed governor 86) the electronic con-trol 119 may assume control of the governor 30 as explained here-after.
The electronic control 119 monitors the speed of the engine 20 for detection of operation of the engine at a pre-determined governed or set speed such as 4000 rpm, and at at least three other speeds having predetermined relations to the set speed: A precall speed which may be 600 rpm below the set speed, a close throttle speed which may be 400 rpm below the set speed, and an overspeed speed which may be 300 rpm above the set speed.
Upon acceleration of the engine and detection of the precall speed, 3400 rpm in this example, the control 119 initiates a timing circuit, and, if within a predetermined time period such as .2 seconds, the close throttle speed of 3600 rpm is detected, then the control 119 will connect electrical power (from the engine electrical system) to the motor 132 to cause it to rotate in close throttle direction, thereby turning the lead screw 140 appropriately to cause the carrier 88 to move in clockwise or close throttle direction away from its rest position. Once initiated, this close throttle movement of the carrier 88 will continue until the carrier contact 128 touches the reference position con-tact 116, thereby automatically moving the carrier 88 to a reference ~ ~196~
position which has been preset to allow an unloaded enyine speed just slightly above the set speed (4000 rpm in this example) of the electronic control 119. If acceleration of the speed of the engine 20 from 3400 rpm to 3600 rpm takes longer than .2 seconds, the control 119 takes no further action, and the engine speed governor 90 remains unactuated until the engine speed reaches the 4000 rpm set speed, at which time the control 119 energizes the motor 132 in the close throttle direction to move the carrier 88 to its reference position.
If upon arrival of the carrier 88 at its reference position, the engine speed is detected by the electronic control 119 to be at 4000 rpm or within a range thereabove extending to 4300 rpm (the overspeed speed in this example), then the electronic control 119 will react to the carrier contact 128 touching (there-by making electrical contact with) the reference position contact 116 by reversing the energization of the motor 132 to the open throttle mode, whereupon the carrier 88 is moved counter-clockwise until the carrier contact 128 breaks contact with the reference position contact 116. Once the electrical circuit between con-tacts 128 and 116 is broken, a continuing detection of an engine speed within the aforesaid range of 4000-4300 rpm causes the con-trol 119 to again energize the motor 132 in the closed throttle direction to drive the carrier contact 128 back to the reference position contact 116 for continuing repetition of the open throttle-close throttle driving cycle in a so-called "alternating circuit" mode of operation so long as the engine speed remains in the 4000-4300 rpm range. In the preferred embodiment of the present invention, the movement of the carrier contact during the repetitive cycle may be only .005-.010 inch, so that the cable 38 may move little or none, what with normal clearances and backlash ~51S~
in the apparatus. The throttle plate 35 is thus limited to being opened to a corresponding reference position, even though the accelerator pedal may be fully depressed, and will initially be closed to the reference position by the overriding action of the carrier 38. If upon arrival o~ the carrier contact 128 at the reference contact 116, the engine speed is below 4000 rpm, the control 119 will reverse the motor 132 to the open throttle direction and release control of the motor 132 to the load speed governor contacts 134 and 138 for return of the carrier 88 to its wide-open-throttle or rest position.
If upon arrival of the carrier contact 128 at the reference contact 116 the engine speed has reached the overspeed speed of 4300 rpm, then the control 119 will cause the electrical contact between contacts 128 and 116 to be ignored, and the carrier 88 will continue to be driven in close throttle direction past the reference contact 116 until the control 119 detects engine speed within the 4000-4300 rpm range or the carrier reaches its maximum close throttle, idle, or overspeed position. This condition normally will occur only when an overrunning load has been applied to the governed engine, such as running the associated vehicle down a steep hill, or when the switch plate 92 has been miss-set. Upon deceleration of the engine speed to within the 4000-4300 rpm range, the control 119 will energize the motor 132 in the open throttle direction until the carrier contact 128 loses contact with the reference position contact 116 and the governor 90 will revert to the alternating circuit mode of operation.
In normal operation, three operating conditions should be considered, the first being that where the engine cannot main-tain the governed or set speed with the throttle plate 35 at its reference position because of a heavy load such as an uphill grade, 51~1 so that engine speed falls below the exemplary 4000 rpm set speed after having attained it under Eull throttle and actuated the carrier 88 toward its reference position to 1imit the throttle plate 35 to some lesser opening. As soon as the engine reacts to moving the throttle plate toward its reference position by decele-rating below 4000 rpm, the governor 90 will be deactuated by the control 119, and the carrier 88 will be moved toward open throttle until the engine again accelerates to the set speed of 4000 rpm, which will reverse the carrier into movement toward closed throttle once again--thus the throttle plate 35 will oscillate through a iimited range of positions as necessary to hold the engine speed very near the set speed, the frequency and magnitude of the oscillations of the throttle plate 35 and the engine speed being determined by the interrelationships of engine power, load applied, and gear ratio being used in the transmission 22, or accelerational decelerational capacity of the engine, together with the response speed of the motor 132 and its screw 140 driving the carrier 88.
The second operating condition is that where the reference position of the throttle plate 35 is just sufficient to maintain the engine speed in the 4000-4300 rpm range--in this case, the con-trol 119 will keep the governor 90 in its alternating circuit mode of operation, and the engine speed may wander within the 4000-4300 rpm range while the throttle plate 35 is held at its reference posi-tion (assuming that the accelerator pedal 72 is held depressed at least sufficiently to open the throttle plate 35 that far). If the engine speed goes outside the 4000-4300 rpm range, the governor 30 will be de-actuated below 4000 rpm or go into the overspeed mode of close throttle drive as explained hereinbefore above 4300 rpm.
The third operating condition is that where an over-running load such as a moderate downhill grade is imposed on the engine 20 such that when -the goyernor 30 has acted to close the throttle plate 35 to its idle or overspeed position, as previously explained, then the engine speed drops below 4300 rpm, thereby causing the carrier 88 to move back toward its reference position.
Assuming the accelerator pedal 72 being sufficiently depressed, the throttle plate 35 will open until the engine speed again goes above 4300 rpm and the control 119 causes the carrier to move in close throttle direction again, and the cycle will repeat, allowing small oscillations of the throttle plate 35 about an average position permitting an engine speed of about 4300 rpm and small oscillations of the engine speed about 4300 rpm. Here again, the parameters of engine accelerational/decelerational ability, gear ratio, and carrier 88 response time determining the period and magnitude of the oscillations.
Operation of the engine 20 at speeds below the set speeds is perfectly free of any control by the engine speed governor 90 except in the aforementioned case of rapid acceleration between precall and close throttle speeds of 3400 and 3600 rpm respec-tively.
An electronic logic module 144 (not shown in Figs. 1 and
While such oscillations are not damaging to the engine and may be helpful in encouraging a truck driver to "get out" of a lower gear ratio and into a higher ratio where the engine will be operating more efficiently, it is also advantageous to have an engine governor which allows the engine to be accelerated to its predetermined speed limit with less overshoot beyond that limit than provided by my previous dynamically-surging governor, and which will thereafter bring the engine quickly to run in clcse approximation to the predetermined speed limit, wandering from it only perhaps 1~ when in a very low gear and less in higher gears, and that probably not on any cyclical basis. Such action is obtained basically by positioning the engine throttle to a pre-determined reference position upon acceleration of the engine to a predetermined speed and actuation of the engine governor there-by, rather than by driving the throttle toward a full-closed position as ir. my previous patent application aforesaid.
Such a smooth and gentle control is advantageous for full economy, and for driver and/or passenger comfort, especially for an application such as a school bus engine, and is typical of my present invention which provides such an engine speed governor and also combines it with a load speed governor essen-tially like that of my aforesaid patent. ~he ~.ti~.~6~
present combination functions to safely control engine and load speeds generally like the combination of my aforesaid patent application, except smoothly, without the previously-experienced dynamic-surging in engine speed control mode. The present in-vention includes an overspeed control which acts to close the throttle beyond the reference position toward a completely closed position in the event of prolonged speeding outside a normal range above the predetermined speed limit (as would be possible for a driver proceeding downhill with the accelerator pedal "floored" or calling for maximum throttle opening), thereby retaining generally the feature of my previous invention which acted to close the throttle toward a completely closed position whenever the engine speed remained anywhere above the predeter-mined limit.
Like my previous invention, the apparatus of the pre-sent invention is a standard unit which may be connected to the standard carburetor, ignition system, and speedometer cable of any engine and vehicle, so that it may be applied at the factory or in the field without inconvenience, and spare parts for this apparatus will be the same for any engine-vehicle combination.
However, my present invention also contemplates the use of a lost-motion type overriding carburetor linkage (in place of the equally useable linkage-lengthening capsule disclosed in my aforesaid patent application) which gives a more conventional feel to the accelerator pedal, but with a more complicated parts situation, since each different engine-carburetor com-bination may require different linkage parts and adaptations.
Also, use of a conventional pulse generator connected to the tachometer drive of a Diesel engine is contemplated for appli-cation of the apparatus of the present invention thereto.
6~
Summary of the Invention In an engine governor for limiting the speed of an engine to a set speed and having movable overriding means for limiting the flow of energy-supplying means to the engine, the improvement including means for selectively moving the overriding means for suitably limiting the flow at rates of moving whereby the speed of the engine in unloaded condition follows the moving of the overriding means with only insignificant overrunning of the set speed upon cessation of the moving of the overriding means. The governor may have means for moving the overriding means in flow limiting direction to a predeterminted reference position upon actuation of the governor. The governor of the present invention may also have means for moving the overriding means from the reference position to suitable other positions for limiting the flow to that for operating the engine at speeds in close proximity to the set speed.
The present governor may have means for actuating the governor when the engine is accelerated to a predetermined speed, such as the set speed, and the means for moving the overriding means to suitable other positions may include means for moving the overriding means in a direction away from the reference position and opposite to its limiting direction upon its arrival thereat. Means for causing continuing moving of the overriding means in the aforesaid opposite direction when the engine is operating at speeds below the set speed may be included also.
Preferably, the present governor may be actuated at a predetermined speed which is slower than -the set speed, and may have means for causing the overriding means to move back in limiting direction to the reference position, after its moving away from the reference position in opposite direction to the limiting direction, when the engine is operating at speeds at and above the set speed. The governor may also have means for respec-tively continuing the aforesaid moving away from and to the refer-ence position while the engine is operating at speeds at, and ~ith-in a predetermined range above, the set speed. The means for moving the overriding means to other positions may include means for causing the moving thereto to occur at a substantially slower rate than the moving of the overriding means in the flow limiting direction upon actuation of the governor, and such slower moving may be only in the direction opposite to the limiting direction.
In the preferred embodiment, the present governor has means for monitoring the speed of the engine for detecting an acceleration thereof to a predetermined speed which is slower than the set speed from another lower predetermined speed within a predetermined time period, and for actuating the governor upon detection of such an acceleration. Means is also provided in a preferred embodiment having the repetitive moving away from and to the reference position for causing the overriding means to cease said repetitive moving when the engine is accelerated to operate at a speed exceeding the aforesaid predetermined range, and to move past the reference position in limiting direction for decelerating the engine to operate at a speed within the pre-determined range. Means is also provided to cause the cessation of said repetitive moving and to cause the overriding means to move away from the reference position in a direction opposite to the limiting direction upon subsequent operation of the engine at a speed below the set speed. The preferred embodiment is an engine speed governor and load speed governor combination for an engine and load connected by a multi-ratio transmission and having a driver-operated means for controlling the flow of energy-supplying means to the engine, overriding means for limiting that flow, means for selectively operating the overriding means in flow limiting direction and opposite thereto, high engine speed responsive means for independently causing the operating means to operate in the limiting direction, high load speed responsive means for indepen-dently causing the operating means to operate in the limiting direction, and low engine speed responsive means and low load speed responsive means for jointly causing the operating means to operate the overriding means in the direction opposite to the limiting direction when concurrently responsive, this combination being characterized further by the foregoing improvements as described in this summary taken alternatively or in combination as desired.
Brief Description of the Drawings Fig. 1 is a diagrammatic view showing the engine and load speed governor of the present invention connected to a trans-missionl carburetor linkage, and accelerator pedal of an engine connected to vehicle wheels by the transmission;
Fig. 2 is a diagrammatic view showing mechanical details of the governor proper;
Fig. 3 shows the throttle lin~cage of Fig. 1 in a differ-ent configuration;
Fig. 4 shows the switch plate of the present governor as connected to the electronic control portion thereof;
Fig. 5 shows a schematic circuit diagram of an electro-nic control providing for positioning the throttle-limiting at a reference position;
Fig. 6 shows a schematic circuit diagram of the portion of an alternate electronic circuit providing slow motion of the throttle-limiting means in one direction; and Fig. 7 shows a schematic diagram of a portion o an electronic circuit providing slow motion of the throttle-limiting means as desired.
tion o~ the Preferred Embodiment In the illustrated preferred embodiment, as shown schematically in Fig. 1, an internal combustion engine 20 has connec~ed thereto a transmission 22 for drLving a load 24 such as the drive wheels of a truck. The transmission 22 is of the usual construction which allows automatic or manual shifting of the gears therein to provide various ratios of speeds between the engine 20 and the load 24. Typically, in a truck, the transmission 22 is shifted into "low gear" to start the load 24 moving at very low speeds, as from a standing start, so that the engine 20 can operate at a rotational speed of thousands of revolutions per minute, where it operates most efficiently, while the load 24 is eased into motion by a friction clutch or hydraulic connection (not shown) included in the transmission 22, and a very large torque is applied through the gearing of the transmission 22 ~-o the axle 26 of the drive wheels 28 of the load 24, it being understood that the engine 20 and the transmission 22 are attached to and part of the load 24. As the drive wheels 28 pick up speed, and before the engine 20 reaches some safe limit to its short term rotational speed, such as 4,400 rpm for example, it is desirable to shift the transmission 22 into a "higher gear" ratio where the wheels 28 will turn at a higher rpm relative to the engine 20, and the power of the engine 20 will be applied through the transmission 22 to the wheels 28 to farther accelerate their speed until the engine 20 again approaches its safe rotational speed. This process of accelerating the engine 20 toward its maximum speed and shifting into a "higher gear" continues until the wheels 28 are driving the load or truck 24 along at a safe and suitable road speed, at which time the transmission will be in its nominal "high gear", the load or truck 24 may be running along at 50 miles per hour, and the engine 20 may be revolving at 3,000 rpm.
It is desirable that the road speed of the load 24 should be controlled or governed to some safe speed such as 55 miles per hour and it is also desirable that the speed of the engine 20 be governed or controlled to its maximum safe speed for long term operation, such as a speed of 4000 rpm, and the engine and load speed governor 30 of the illustrated embodiment of this invention has overriding means for limiting the flow of the energy-supplying means or fuel to the engine to automatically and selectively con-trol both speeds with peculiar advantages to each.
The governor 30 is shown schematically in Fig. 1 connec-ted to the load side of the transmission 22 by the flexible rotary cable 31, which may be the typical "speedometer cable", and which transmits rotary motion at a speed proportional to the speed of the wheels 28. A gear 32 connected to the cable 31 inside the housing 33 drives an output gear 34 which is connected to a speedometer cable C for driving a speedometer S which may be located on the dashboard of the truck cab. Governor 30 is connected to the carburetor throttle plate 35 of the carburetor 36 of the engine 20 by a flexible pull cable 38 enclosed within a flexible sheath 40 of fixed length attached to and extended from the governor 30, as shown in Figs. 1 and 2. The connection between throttle plate 35 and cable 38 is by means of the throttle arm 42 mounted on throttle shaft 44 to which the throttle plate 35 is affixed, and a stud 46 fixed in the free end 48 of the throttle arm ~2 intermediately thereof forms a mounting point for a pivotable eye fitting 50 which is permanently attached to the free end of the cable 38.
The extended end of the flexible shea-th 40 is attached to a bracket 52 mounted to the carburetor 36 for holding the end of the sheath 40 in general alignment with the stud 46 and the eye fitting 50 on the extending end of the cable 38. A first tension spring 54 is stretched between a first pin 56 installed near the extremity of the free end 48 of the throttle arm 42 and a second pin 58 is fixed in relation to the carburetor 36 for hold-ing the throttle plate 35 in its normally nominally closed or idle position as shown in Fig. 1 in solid lines. An accelerator arm 60 is mounted for free rotation on the throttle shaft 44 and is connected to the throttle arm 42 by a second extension spring 62 stretched between a third pin 64 and a fourth pin 66, the pins being respectively fixed in the free ends of the arms 42 and 60.
The spring 62 is substantially stronger than the spring 54. A
stop 68 on an extending portion 70 of the accelerator arm 60 is biased against the throttle arm 42 by the spring 62 under normal idling conditions for the engine 20.
An accelerator pedal 72 is normally biased to an idle position against a pedal stop 74 by a third extension spring 76 of suitable strength and is suitably freely pivoted on a pedal shaft 78 for pedal actuation to a full or wide open throttle position (indicated by the numeral 72') against a floorboard stop 80. The lower end of the pedal 72 is connected to a fifth pin 82 mounted on the free end of the accelerator arm 60 by a link 84 pivotable at the pedal 72 and the pin 82. The link 84 is of suit-ably adjusted length to place the pedal 72, the accelerator arm 60, and the throttle arm 42 simultaneously in their respective normal or idle positions as shown in solid lines in Fig. 1.
When the governor 30 is in its normal or unactuated condition, the cable 38 may be freely pulled out from its sheath ;~5~
40 by pivoting the throttle arm 42 counter-clockwise against the bias of the spring 54. sy depressing the pedal 72 against stop 80 to its wide open position, the accelerator arm 60 will be rotated counterclockwise -to its wide open throttle position as shown in broken lines and indicated by the numeral 60' in Fig. l;
and the spring 62 will pull the throttle arm 42 to its wide open throttle position as shown in broken lines and indicated by the numeral 42'.
When the governor 30 has been actuated as described hereinafter, and the eye fitting S0 at the extending end of the cable 38 has been pulled back toward its normal or idle position as shown in solid lines, the counter-clockwise movement of the throttle arm 42 will be limited accordingly, and the spring 62 will be stretched as necessary to accommodate any mismatch between the position of the pedal 72 and the position of the throttle arm 42~ The extreme mismatch, as shown in Fig. 3, occurs when the pedal 72 is at the wide open throttle position and the throttle arm 42 has been limited to its idle position by withdrawal move-ment of the cable 38, the spring 62 is at its maximum stretched condition, and the cable 38 extending from the governor 30 is thereby fully overriding the call from the accelerator pedal 72 for full throttle. Intermediate positions of the pedal 72 and the arm 60 are available at the will of the operator, as are intermediate positions of the throttle arm 42 as permitted by the limiting action of the cable 38.
The pedal 72 is thereby free to be positioned wherever the operator desires, and so long as the governor cable 38 is in its fully extended, normal, non-limiting position, the accelerator arm 60 and the throttle arm 42 will be biased together by the spring 62 to move as one, and the throttle plate 34 will open and close according to the position of the pedal 72. If the cable is retracted to limit the throttle opening, the spring 62 will stretch as necessary upon depression of the pedal 72 so that the accelerator pedal will have a generally normal feel just as a conventional accelerator pedal and throttle linkage. The accelera-tor pedal and throttle and carburetor linkage disclosed is schematic and representative of infinite mechanically equivalent variations to suit particular engine-carburetor-vehicle combina-tions. Particularly, torsion springs may be substituted for the tension springs disclosed, for space and configuration considera-tions, and a similar apparatus could be adapted for use with the control lever of a Diesel or gasoline fuel injection system, or other means of limiting the flow of energy-supplying means to a motor or engine, even an electric one.
The construction and operation of the load speed gover-nor portion 86 of the present invention as shown in Fig. 2 is generally the same as that disclosed in my aforesaid patent appli-cation, and no further disclosure is needed herein except to point out the additional elements incorporated therewith as shown ir Figs. 2 and 4 to provide means for moving the carrier 88 to a pre-determined reference position upon actuation of the engine speed governor portion 90 of the engine and load speed governor 30:
An arcuate switch plate 92 is mounted to pivot for adjust-ment about the carrier shaft 94 which is affixed to the housing 33 by means of a bracket 96 attached inside the housing. The plate 92 is formed of insulating material and is mounted on a metal hub 98 which is mounted for pivoting on the shaft 94. The hub 98 has an attachment flange 100 to which the plate 92 is fastened by rivets 102. The plate 92 is located directly behind the carrier 88 within the housing 33, and the bracket 96 supports the shaft 94 between the carrier 88 and the hub 98. The shaft 94 and hub 98 mounted thereon extend rearwardly through an opening in the housing 33. Outside the housing 33 a crank arm 104 is attached to the hub 98 and has an extending end in which is mounted a pivotable stud 106 having a threaded cross hole into which is threaded an adjustment screw 108. The shank of the screw 108 at the head end thereof passes through a clearance hole in a stud 110 fastened to the outside of the housing 33, and a compression spring 112 mounted on the screw 108 between the studs 106 and 110 holds the two studs 106 and 110 biased firmly apart to a distance limited by the head 114 of the screw 108.
Thus, rotary adjustment of the screw 108 acts to change the distance between the studs 106 and 110, thereby pivoting the switch plate 92 about the shaft 94 to set the plate 92 at any desired position within a suitable range of adjustment. Such positioning is desirable in order to angularly place a reference position contact 116 as desired in relation to the carrier 88.
The contact 116 is mounted on the switch plate 92 in arcuate rela-tion to the hub 98, and is connected to an electrical lead 118 for connection to the electronic control portion 119 of the governor 30 as explained hereinafter. The contact 116 extends clockwise from a generally central portion of the arcuate shape of the plate 92, and a somewhat similar limiting contact 120 is mounted on the plate 92 spaced a small gap 122 counter-clockwise from the contact 116 and extending along the same arc as contact 116 in a counter-clockwise direction generally to the left side of the plate 92. The contact 120 is connected to an electrical lead 124 for connection to the electronic control portion 119.
An electrically conductive spring leaf 126 having a carrier electrical contact 128 at one end thereof is fastened at the other end to the rear side of the carrier 88 by rivets 130 and is sprung away from the carrier 88 for spring-biased contact with the switch plate 92 and the contacts 116 and 120 along the arcs thereof wherever the carrier 88 may be positioned as explained in my aforementioned patent application or to be explained herein-after. By its connection to the carrier 88, the contact 128 is a grounding contact so far as the electronic control portion of the governor is concerned. In Fig. 4 the carrier 88 has been broken away, and the spring leaf 126 and the contact 128 are shown in more detail in relation to the switch plate 92. The left, or counter-clockwise end of the reference position contact 116 forms the actual reference point or position to which the carrier contact 128 is moved and homed for establishing a reference position for the carrier 88 and thereby the overriding means for limiting the flow of energy-supplying means which is an object of the present nvention .
A reversible electric motor 132 is included in the electronic control 119, as are the accelerate or open throttle contact 134, the decelerate or close throttle contact 136, and the grounding contacts 138 which control the motor 132 at the command of the load speed governor 86 to turn the lead screw 140 which in turn causes the carrier 88 to move in rotation on the shaft 94.
In simplest terms, the governor 30 of the present inven-tion functions as follows: In the absence of a signal to the contrary, either from the load speed governor 86 or the engine speed governor 90, the load speed governor 86 acts to move the carrier 88 to its extreme counter-clockwise, rest, or wide-open-throttle position as shown in Fig. 2, where the flow of fuel or energy~supplying means to the engine 20 is not limited at all by the governor 30, but is dependent upon the operator-positioned accelerator and throttle linkages as described hereinbefore and in my aforementioned prior patent application. Then, in the absence of a load speed sufficient to actuate the load speed gover-~ ~.
,, r~ nor 86 as described in my aEoresaid patent _~p~Le~on (e.g. whenthe transmission 22 is in neutral, or in a lower gear ratio whexe the engine must reach a speed far above the governed speed in order to actuate the load speed governor 86) the electronic con-trol 119 may assume control of the governor 30 as explained here-after.
The electronic control 119 monitors the speed of the engine 20 for detection of operation of the engine at a pre-determined governed or set speed such as 4000 rpm, and at at least three other speeds having predetermined relations to the set speed: A precall speed which may be 600 rpm below the set speed, a close throttle speed which may be 400 rpm below the set speed, and an overspeed speed which may be 300 rpm above the set speed.
Upon acceleration of the engine and detection of the precall speed, 3400 rpm in this example, the control 119 initiates a timing circuit, and, if within a predetermined time period such as .2 seconds, the close throttle speed of 3600 rpm is detected, then the control 119 will connect electrical power (from the engine electrical system) to the motor 132 to cause it to rotate in close throttle direction, thereby turning the lead screw 140 appropriately to cause the carrier 88 to move in clockwise or close throttle direction away from its rest position. Once initiated, this close throttle movement of the carrier 88 will continue until the carrier contact 128 touches the reference position con-tact 116, thereby automatically moving the carrier 88 to a reference ~ ~196~
position which has been preset to allow an unloaded enyine speed just slightly above the set speed (4000 rpm in this example) of the electronic control 119. If acceleration of the speed of the engine 20 from 3400 rpm to 3600 rpm takes longer than .2 seconds, the control 119 takes no further action, and the engine speed governor 90 remains unactuated until the engine speed reaches the 4000 rpm set speed, at which time the control 119 energizes the motor 132 in the close throttle direction to move the carrier 88 to its reference position.
If upon arrival of the carrier 88 at its reference position, the engine speed is detected by the electronic control 119 to be at 4000 rpm or within a range thereabove extending to 4300 rpm (the overspeed speed in this example), then the electronic control 119 will react to the carrier contact 128 touching (there-by making electrical contact with) the reference position contact 116 by reversing the energization of the motor 132 to the open throttle mode, whereupon the carrier 88 is moved counter-clockwise until the carrier contact 128 breaks contact with the reference position contact 116. Once the electrical circuit between con-tacts 128 and 116 is broken, a continuing detection of an engine speed within the aforesaid range of 4000-4300 rpm causes the con-trol 119 to again energize the motor 132 in the closed throttle direction to drive the carrier contact 128 back to the reference position contact 116 for continuing repetition of the open throttle-close throttle driving cycle in a so-called "alternating circuit" mode of operation so long as the engine speed remains in the 4000-4300 rpm range. In the preferred embodiment of the present invention, the movement of the carrier contact during the repetitive cycle may be only .005-.010 inch, so that the cable 38 may move little or none, what with normal clearances and backlash ~51S~
in the apparatus. The throttle plate 35 is thus limited to being opened to a corresponding reference position, even though the accelerator pedal may be fully depressed, and will initially be closed to the reference position by the overriding action of the carrier 38. If upon arrival o~ the carrier contact 128 at the reference contact 116, the engine speed is below 4000 rpm, the control 119 will reverse the motor 132 to the open throttle direction and release control of the motor 132 to the load speed governor contacts 134 and 138 for return of the carrier 88 to its wide-open-throttle or rest position.
If upon arrival of the carrier contact 128 at the reference contact 116 the engine speed has reached the overspeed speed of 4300 rpm, then the control 119 will cause the electrical contact between contacts 128 and 116 to be ignored, and the carrier 88 will continue to be driven in close throttle direction past the reference contact 116 until the control 119 detects engine speed within the 4000-4300 rpm range or the carrier reaches its maximum close throttle, idle, or overspeed position. This condition normally will occur only when an overrunning load has been applied to the governed engine, such as running the associated vehicle down a steep hill, or when the switch plate 92 has been miss-set. Upon deceleration of the engine speed to within the 4000-4300 rpm range, the control 119 will energize the motor 132 in the open throttle direction until the carrier contact 128 loses contact with the reference position contact 116 and the governor 90 will revert to the alternating circuit mode of operation.
In normal operation, three operating conditions should be considered, the first being that where the engine cannot main-tain the governed or set speed with the throttle plate 35 at its reference position because of a heavy load such as an uphill grade, 51~1 so that engine speed falls below the exemplary 4000 rpm set speed after having attained it under Eull throttle and actuated the carrier 88 toward its reference position to 1imit the throttle plate 35 to some lesser opening. As soon as the engine reacts to moving the throttle plate toward its reference position by decele-rating below 4000 rpm, the governor 90 will be deactuated by the control 119, and the carrier 88 will be moved toward open throttle until the engine again accelerates to the set speed of 4000 rpm, which will reverse the carrier into movement toward closed throttle once again--thus the throttle plate 35 will oscillate through a iimited range of positions as necessary to hold the engine speed very near the set speed, the frequency and magnitude of the oscillations of the throttle plate 35 and the engine speed being determined by the interrelationships of engine power, load applied, and gear ratio being used in the transmission 22, or accelerational decelerational capacity of the engine, together with the response speed of the motor 132 and its screw 140 driving the carrier 88.
The second operating condition is that where the reference position of the throttle plate 35 is just sufficient to maintain the engine speed in the 4000-4300 rpm range--in this case, the con-trol 119 will keep the governor 90 in its alternating circuit mode of operation, and the engine speed may wander within the 4000-4300 rpm range while the throttle plate 35 is held at its reference posi-tion (assuming that the accelerator pedal 72 is held depressed at least sufficiently to open the throttle plate 35 that far). If the engine speed goes outside the 4000-4300 rpm range, the governor 30 will be de-actuated below 4000 rpm or go into the overspeed mode of close throttle drive as explained hereinbefore above 4300 rpm.
The third operating condition is that where an over-running load such as a moderate downhill grade is imposed on the engine 20 such that when -the goyernor 30 has acted to close the throttle plate 35 to its idle or overspeed position, as previously explained, then the engine speed drops below 4300 rpm, thereby causing the carrier 88 to move back toward its reference position.
Assuming the accelerator pedal 72 being sufficiently depressed, the throttle plate 35 will open until the engine speed again goes above 4300 rpm and the control 119 causes the carrier to move in close throttle direction again, and the cycle will repeat, allowing small oscillations of the throttle plate 35 about an average position permitting an engine speed of about 4300 rpm and small oscillations of the engine speed about 4300 rpm. Here again, the parameters of engine accelerational/decelerational ability, gear ratio, and carrier 88 response time determining the period and magnitude of the oscillations.
Operation of the engine 20 at speeds below the set speeds is perfectly free of any control by the engine speed governor 90 except in the aforementioned case of rapid acceleration between precall and close throttle speeds of 3400 and 3600 rpm respec-tively.
An electronic logic module 144 (not shown in Figs. 1 and
2) for the electronic control portion 119 of the governor 90 is mounted within the housing 33 of the governor 30. As shown schematically in Fig. 5, the module 144 includes conventional integrated circuits and electronic components which operate as described below to receive negative pulse signals from an internal combustion engine ignition coil (or alternatively from a pulse generator connected to a Diesel engine or other prime mover~, and signals from the switch plate contact 116 and the open and close throttle contacts 134 and 136 respectively, in order to control the reversible electric motor 132 as described hereinbefore.
36i To control engine speed a me-thod is first needed to detect the engine speed. This is accomplished by a requency to voltage converter. The engine speed is proportional to the number of ignition pulses per minute as monitored at the negative terminal of the ignition coil of the engine 20. These pulses are fed into terminal A. Voltage divider resistors Rl and R2 are selected so that the transistor Ql (normally off) will turn on once for each ignition pulse. A resistor R3, a variable potentiometer Pl and a capacitor Cl form a resistor-capacitor timing network. For each ignition pulse, the transistor Ql will turn on, and in turn fully discharge the capacitor Cl. As the engine speed increases, the transistor Ql will turn on more frequently. With the transistor Ql off, the capacitor Cl starts to charge. As the volta~e rises on the capacitor Cl to approximately 1/2 of the ten volt supply voltage, the logic norgate ICl-l of the quad norgate ICl will have its output (pin 3) change state from high to low. When the output is high, the capacitor C2 is being charged through the resistor R4.
A change in output from high to low will cause the capacitor C2 to be discharged. By properly selecting the values of R3, Pl, Cl, R4 and C2, an average voltage will appear on the capacitor C2 which is proportional to engine speed. The faster the engine speed (ignition pulses) the higher the voltage, the slower the engine speed the lower the average voltage.
A voltage comparator circuit is used to determine when various predetermined engine speeds occur. The speeds are:
precall, close throttle, governed, and overspeed. The circuit consists of a quad voltage comparator IC2 and five resistors Rl9, R5, R9, R10, and Rll which set the individual voltages at which each comparator functions.
~he precall and close throttle comparators operate cooperatively in sequence. Their purpose is to determine whether the engine is accelerating in speed so fast that the engine speed governor should be actuated before the set speed is reached. If this condition occurs, the precall and close throttle comparators IC2-1 and IC2-2 act together to start the governor operating even before the predetermined governed speed is reached. A typical example would have the precall speed set at 3400 RPM, the close throttle speed at 3600 RPM, the governed speed at 4000 RPM and the overspeed at 4300 RPM. If the engine should accelerate between 3400 and 3600 RPM within 200 milisec, this rate of acceleration would cause the close throttle norgate ICl-2 to function to operate and activate the governor. When the engine speed increases at a slower rate the precall close throttle circuitry is inoperative and plays no part in the operation.
Upon reaching 4000 RPM, the governor or set speed comparator IC2-3 begins its normal governing. At 4300 RPM the overspeed comparator IC2-4 turns on, causing the governor 90 to go toward completely closing the throttle plate 35.
When the engine acceleration exceeds the normal governor reaction capability, the close throttle comparator IC2-2 causes the control 119 to start the governing process prior to 4000 RPM
being reached. In the event of such a condition, the precall and close throttle comparators IC2-1 and IC2-2 provide signals to the close throttle norgate ICl-2 which in turn provides a signal to a flip-flop circuit composed of the two norgates IC1-3 and IC1-4. With the proper signal the flip-flop circuit is set so that the output of pin 4 of ICl-4 goes high and acts through the norgates IC3-1 and IC3-2 of the quad norgate IC3 to cause the transistor Q2 to drive the motor 132 and the associated carrier contact 128 in the close throttle direction. Upon the carrier contact 128 reachin~ the normally open re~erence position contact 116 of the switch plate 92 the flip flop circuit receives a reset signal from the norgate IC3-3 at pin 5 of the norgate ICl-4 and pin 4 thereof goes low. The precall close throttle function cannot reoccur unless the engine speed drops below the 3400 RPM
precall level, and only then could the process be repeated.
The quad norgate IC3 comprises the logic circuitry which allows the electronic logic module 114 to control the governor 90 in proper sequence. Pin 6 of norgate IC3-1 is normally low. With a high signal at pin 6, the output pin 4 of norgate IC3-1 goes low and causes the output pin 10 of norgate IC3-2 to go high. This will turn on the transistor Q2 and drive the motor 132 in the close throttle direction. The motor continues driving the carrier 88 in the close throttle direction until its contact 128 reaches the reference position contact 116. Grounding the reference con-tact 116 causes pin 2 of the norgate to go low and pin 3 thereof to go high. Pin 3 going high will cause pin 10 of the norgate IC3-2 to now go low. When pin 10 goes low, it causes pin 11 of the norgate IC3-4 to go high which turns on the transistor Q3, driving the motor 132 in the open throttle direction. The carrier 88 going in the open throttle direction will remove the carrier contact 128 from the reference contact 116 and change pin 2 of the norgate IC3-3 from low back to high and the process will keep repeating. This operation is known as the alternating circuit feature since the motor 132 will alternately drive the carrier contact 128 on and off the reference contact 116. The amount of movement is very small and effectively keeps the carrier 88 at its reference position at the threshold of the reference position contact 116.
Should the engine speed keep increasing to 4300 RPM as does happen in some isolated ins-tances, it is necessary that the alternating circuit mode be overridden so that the motor will drive the carrier con-tact 128 past the threshold of the reference contact 116 fully in the close throttle direction. When such an instance is detected by the overspeed comparator IC2-~, pin 14 thereof goes high and continually holds pin 3 of the norgate IC3-3 low. This overcomes the effect of the reference contact 116 being grounded at pin 2 of the norgate IC3-3 and allows pin 10 of the norgate IC3-2 to remain high as long as the overspeed condition exists. Dropping below the overspeed value of 4300 RPM allows the governor comparator IC2-3 circuitry to govern as normal.
The Zener diode ~1 in series with the resistor R 18 across the 12 volt battery supply voltage, as shown in Fig. 5, provides a stabilized 10 volt supply for the logic module 144 as indicated at various points therein.
An alternative second embodiment of the engine speed governor 90 provides for operation of the motor 132 (and thereby the carrier 88) at a substantially slower speed in open throttle direction than in close throttle direction--approximately 15-18 seconds to rotate the carrier 88 from idle position to wide-open-throttle position as compared to about 3 seconds to rotate it from wide-open-throttle to idle position. The slower speed is accomplished by the circuitry of Fig. 6, which shows in schematic detail the changes and additions to the circuitry of Fig. 5--the portions of Fig. 5 which are not repeated in Fig. 6 are identical in both circuits. The additional resistor R20 in the connection between the transistor Q3 and the motor 132 serves to reduce the voltage supplied to the motor, and with the resultant reduced speed, it is desirable that, upon arrival of 'he carrier contact 30 128 at the reference contact 116 subsequent to actuation of the governor 90, that the contact 128 should remain at the reference ~5~
contact so long as the engine speed remains in the ~000-4300 RPM
range. Therefore, the pln 13 of the noryate IC3-4 is now connected to limiting circuitry comprising the trans~stors Q4, Q5, and Q6 and their associated added components. Now, when the contact 128 touches the contact 116, the motor 132 is turned off, and so long as the engine speed remains in the 4000-4300 RPM range, it remains off. If the engine speed drops below 4000 RPM, the governor com-parator IC2-3 will cause the motor 132 to run in open throttle direction (at the slow speed) until the engine again rises to 4000 rpm, or until the carrier 88 moves in open throttle direc-tion sufficiently for the carrier contact 128 to cross the narrow gap 122 and touch the limiting contact 120 on the switch plate 92--in either case, the open throttle drive ceases; and in the first case the governor comparator IC2-3 causes the motor 132 to drive in the close throttle direction, while in the second case the carrier contact 128 remains at the limiting contact until the engine either rises to 4000 RPM and the governor comparator IC2-3 causes close throttle drive, or the engine drops below the precall speed of 3400 RPM and the precall comparator IC2-1 causes open throttle drive, carrying the carrier contact 128 past its initial contact with the limiting contact 120 toward the wide-open-throttle position of the carrier 88.
This second, slow speed, embodiment is advantageous for lessening engine speed oscillations, but is disadvantageous in that the slow travel of the carrier 88 toward open throttle may sometimes handicap the operator who is trying to get a rapid acceleration of the engine for shifting gears.
Yet a third embodiment of my engine speed governor inven-tion provides for normally fast travel of the carrier 88 toward its reference position upon actuation of the engine speed governor 90 untll the carrier contact 128 moves off the limiting con-tact 120, at which the motor 132 drops to a very slow speed resulting in clockwise movement of the carrier 88 about its shaft 94 at the rate of about one-third RPM, which would be rouyhly equivalent to full travel from wide-open-throttle position to idle throttle position in about thirty seconds. An objective of this slow speed is to move the carrier 88 in limiting control of 'che throttle plate 35 at a slower rate than the response capability of the engine 20, thereby minimizing engine speed oscillations. Since the response capability of the engine will vary considerably according to loads and gear ratios, recovery time (from the loss of engine speed due to sudden application of a heavy load while running at the governed speed under light load) could be somewhat slow--however, this is not the usual condition and is overweighed by the stability of the system for normal operation.
The relation of engine response capability rate and throttle limiting means movement rate is a complex one, but consider that any engine running at idle speed and having full throttle suddenly applied will take a second or two to reach a speed of say 4000 RPM, and if a governor acts to close the throttle quickly to closed or idle throttle position upon attainment of the 4000 RPM speed, the engine speed will overshoot or overrun the 4000 RPM speed and then decelerate below the 4000 RPM speed and undershoot or underrun it, even though the governor acts to open to full throttle again immediately upon the speed dropping below 4000 RPM. This may cause oscillations of engine speed of 1000 RPM or more in an unloaded engine, rapidly enough to be disturbing to its operator, and resulting in a governor with very poor regulation. This is an example of a throttle limiting means moving at a very much faster rate than the engine response capa-bility rate, and results in out-of-phase operation of engine and 6~
throttle as explained in my aforesaid ~ patent a~ ~a~n.
~ .
On the other hand, it has beell found tha-t where the throttle can only be moved between idle and full positions over a period of about twenty seconds or more, then in-phase operation of engine and throttle occurs, as in the present invention, and very good governor regulation can be obtained. The engine has the capability of increasing its speed with very little lag behind the throttle position, even under heavy or full load, meaning that if the throttle is opened half-way at this slow rate or slower, that the engine will have come up in speed slowly with the slow opening and will have achieved its maximum sustained speed for this throttle opening and particular load momentarily after the throttle movement stops, and will overrun the aforesaid maximum sustained insignificantly, thereby staying essentially in phase with the throttle, even under no load conditions. In the commercial engine application range considered so far, an approximately twenty to twenty-five second throttle movement period seems about the optimum for satisfactory governor regula-tion for a smoothly operating governor and a period as short as seven or eight seconds causes objectionable oscillations. Of course, to obtain satisfactory restraint under no load engine run-up conditions and satisfactory recovery from sudden load applications, it is desirable to have fast throttle closing upon sudden acceleration of the engine, and fast throttle opening upon sudden deceleration. The apparatus of the present invention provides such capability for both fast and slow throttle movement through the use of a reference position for the throttle limiting means, such that throttle movement will be slow under normal conditions, but may be swift when needed for recovery of control of a rapidly fluctuating engine speed caused by some factor external to the governor. To date, the apparatus of the present invention is the only known solution to this problem for every-day commercial use, e.g., as for truck and bus engines. Upon arrival at its reference posltion, assuming that the engine speed still lies in the A000-4300 RPM range, the carrier stops and remains in place, moving therefrom only upon detection of engine speed outside the 4000-4300 RPM range, and only at the above-mentioned slow speed, whether in open throttle or close throttle direction.
When the engine speed drops below 4000 RPM, the motor 132 is energized at the slow speed in open throttle direction and continues in that direction until the carrier contact 128 hits the limiting contact 120 and halts there, unless in the meantime the engine speed has risen again to 4000 RPM to cause the motor 132 to be reversed to close throttle direction, or has dropped below the 3400 RPM precall speed which will cause the carrier 88 to continue to open throttle direction, but at high speed a~ter touching the contact 120. If the carrier contact 128 is halted upon touching the limiting contact 120, it remains there pending detection of engine speed rising to 4000 RPM to cause close throttle drive at the slow speed, or engine speed falling below the 3400 RPM precall speed to cause open throttle drive just as in the second embodiment; however, the motor 132 will return to its normal fast speed because the carrier contact 128 is contact-ing the limiting contact 120.
As a practical matter, on a long steep grade in a truck engine application, where a considerably open throttle position is required to maintain the engine at the 4000 RPM
governed speed, after the throttle limiting means has been moved to the reference position, then the governor will allow the 5~
throttle to slowly open farther to a poin-t where its average position ~urnishes just the fuel needed to maintain 4000 RPM with only minor oscillations thereabout as the throttle is opened and closed slightly by governor detection of engine speed falling below 4000 RPM and then rising back to that speed.
The circuitry for obtaining the slow-motor speed in both directions, and only when the carrier contact 128 is out of contact with the limiting contact 120, comprises essentially a suitable resistor R31 placed in the 12 volt common supply connec-tion to the motor 132 as shown in Fig. 7 in partial schematicdetail. The resistor R31 reduces the voltage across the motor 132 sufficiently to cause it to run at the desirable low speed in close throttle direction where the force of the load speed governor spring 142 and throttle apparatus springs must be overcome, and a second resistor R30 in the open throttle connec-tion between the transistor Q3 and the motor 132 reduces the voltage across the motor even farther to compensate for the over-running ~orce applied by the governor spring 142 and throttle apparatus springs when the motor runs in throttle opening direc-tion. A PNP transistor Q7 is connected in parallel with theresistor R31 and is controlled indirectly through additional circuitry (not shown) associated with the limiting contact 120 by the condition thereof. When contact 120 is grounded by contact with the carrier contact 128, the transistor Q7 is caused to be conductive, the resistor R31 is shunted out of the circuit and is of no effect, and the motor 132 runs at normal fast speed.
When the carrier contact 128 leaves the limiting contact 120, leaving it ungrounded, then the transistor Q7 goes non-conducting and all current to the motor 132 must pass through the resistor 31, so that the motor runs at the desirable slow speed.
This third, slow speed, embodiment lessens the oscilla-tions of engine speed, and would be preferable to the first, alternating circuit, embodiment except that the low motor voltages required to obtain a sui-tably slow operation of the motor 132 may not provide sufficient starting torque for reliable motor operation under extreme cold weather conditions. However, gover-nors 30 according to this third embodiment have worked satis-factorily in moderate temperature conditions and commercially demonstrate the advantages of slow speed operation of the motor 132.
Control of the motor 132 by the load speed governor 86 (through movement of the carrier 88 and its open throttle and close throttle contacts 134 and 136 respectively, by action of the flyball mechanism 146 to move the grounding contacts 138) is the same as that disclosed in my aforementioned prior patent application, whereby the load speed governor can overridingly run the moto~ 132 in close throttle direction in response to suit-ably high load speed at any time, and the engine speed governor 90 can do likewise at any time in response to a suitably high engine speed, but the load speed governor can only run the motor 132 in open throttle direction in response to a suitably low load speed when the engine speed governor 90 is also calling concurrently for the motor to operate in that direction in response to a suitably low engine speed by making the transistor Q3 conductive, and vice-versa.
The present invention has been described in detail above for purposes of illustration only and is not intended to be limited by this description or otherwise to exclude any variation or equivalent arrangement that would be apparent from, or reasonably suggested by, the foregoing disclosure to the skill of the art, such as the substitution of vacuum or mechanical or other actuators, or the electrically driven lead screw dis-closed herein, the substitution of centrifugal or magnetic or other engine speed responsive means for the electronic module disclosed herein, or the substitution of magnetic or electronic or other load speed responsive means for the fly ball mechanism disclosed herein. I.e., the scope of the present invention is to be determined by the scope of the appended claims.
36i To control engine speed a me-thod is first needed to detect the engine speed. This is accomplished by a requency to voltage converter. The engine speed is proportional to the number of ignition pulses per minute as monitored at the negative terminal of the ignition coil of the engine 20. These pulses are fed into terminal A. Voltage divider resistors Rl and R2 are selected so that the transistor Ql (normally off) will turn on once for each ignition pulse. A resistor R3, a variable potentiometer Pl and a capacitor Cl form a resistor-capacitor timing network. For each ignition pulse, the transistor Ql will turn on, and in turn fully discharge the capacitor Cl. As the engine speed increases, the transistor Ql will turn on more frequently. With the transistor Ql off, the capacitor Cl starts to charge. As the volta~e rises on the capacitor Cl to approximately 1/2 of the ten volt supply voltage, the logic norgate ICl-l of the quad norgate ICl will have its output (pin 3) change state from high to low. When the output is high, the capacitor C2 is being charged through the resistor R4.
A change in output from high to low will cause the capacitor C2 to be discharged. By properly selecting the values of R3, Pl, Cl, R4 and C2, an average voltage will appear on the capacitor C2 which is proportional to engine speed. The faster the engine speed (ignition pulses) the higher the voltage, the slower the engine speed the lower the average voltage.
A voltage comparator circuit is used to determine when various predetermined engine speeds occur. The speeds are:
precall, close throttle, governed, and overspeed. The circuit consists of a quad voltage comparator IC2 and five resistors Rl9, R5, R9, R10, and Rll which set the individual voltages at which each comparator functions.
~he precall and close throttle comparators operate cooperatively in sequence. Their purpose is to determine whether the engine is accelerating in speed so fast that the engine speed governor should be actuated before the set speed is reached. If this condition occurs, the precall and close throttle comparators IC2-1 and IC2-2 act together to start the governor operating even before the predetermined governed speed is reached. A typical example would have the precall speed set at 3400 RPM, the close throttle speed at 3600 RPM, the governed speed at 4000 RPM and the overspeed at 4300 RPM. If the engine should accelerate between 3400 and 3600 RPM within 200 milisec, this rate of acceleration would cause the close throttle norgate ICl-2 to function to operate and activate the governor. When the engine speed increases at a slower rate the precall close throttle circuitry is inoperative and plays no part in the operation.
Upon reaching 4000 RPM, the governor or set speed comparator IC2-3 begins its normal governing. At 4300 RPM the overspeed comparator IC2-4 turns on, causing the governor 90 to go toward completely closing the throttle plate 35.
When the engine acceleration exceeds the normal governor reaction capability, the close throttle comparator IC2-2 causes the control 119 to start the governing process prior to 4000 RPM
being reached. In the event of such a condition, the precall and close throttle comparators IC2-1 and IC2-2 provide signals to the close throttle norgate ICl-2 which in turn provides a signal to a flip-flop circuit composed of the two norgates IC1-3 and IC1-4. With the proper signal the flip-flop circuit is set so that the output of pin 4 of ICl-4 goes high and acts through the norgates IC3-1 and IC3-2 of the quad norgate IC3 to cause the transistor Q2 to drive the motor 132 and the associated carrier contact 128 in the close throttle direction. Upon the carrier contact 128 reachin~ the normally open re~erence position contact 116 of the switch plate 92 the flip flop circuit receives a reset signal from the norgate IC3-3 at pin 5 of the norgate ICl-4 and pin 4 thereof goes low. The precall close throttle function cannot reoccur unless the engine speed drops below the 3400 RPM
precall level, and only then could the process be repeated.
The quad norgate IC3 comprises the logic circuitry which allows the electronic logic module 114 to control the governor 90 in proper sequence. Pin 6 of norgate IC3-1 is normally low. With a high signal at pin 6, the output pin 4 of norgate IC3-1 goes low and causes the output pin 10 of norgate IC3-2 to go high. This will turn on the transistor Q2 and drive the motor 132 in the close throttle direction. The motor continues driving the carrier 88 in the close throttle direction until its contact 128 reaches the reference position contact 116. Grounding the reference con-tact 116 causes pin 2 of the norgate to go low and pin 3 thereof to go high. Pin 3 going high will cause pin 10 of the norgate IC3-2 to now go low. When pin 10 goes low, it causes pin 11 of the norgate IC3-4 to go high which turns on the transistor Q3, driving the motor 132 in the open throttle direction. The carrier 88 going in the open throttle direction will remove the carrier contact 128 from the reference contact 116 and change pin 2 of the norgate IC3-3 from low back to high and the process will keep repeating. This operation is known as the alternating circuit feature since the motor 132 will alternately drive the carrier contact 128 on and off the reference contact 116. The amount of movement is very small and effectively keeps the carrier 88 at its reference position at the threshold of the reference position contact 116.
Should the engine speed keep increasing to 4300 RPM as does happen in some isolated ins-tances, it is necessary that the alternating circuit mode be overridden so that the motor will drive the carrier con-tact 128 past the threshold of the reference contact 116 fully in the close throttle direction. When such an instance is detected by the overspeed comparator IC2-~, pin 14 thereof goes high and continually holds pin 3 of the norgate IC3-3 low. This overcomes the effect of the reference contact 116 being grounded at pin 2 of the norgate IC3-3 and allows pin 10 of the norgate IC3-2 to remain high as long as the overspeed condition exists. Dropping below the overspeed value of 4300 RPM allows the governor comparator IC2-3 circuitry to govern as normal.
The Zener diode ~1 in series with the resistor R 18 across the 12 volt battery supply voltage, as shown in Fig. 5, provides a stabilized 10 volt supply for the logic module 144 as indicated at various points therein.
An alternative second embodiment of the engine speed governor 90 provides for operation of the motor 132 (and thereby the carrier 88) at a substantially slower speed in open throttle direction than in close throttle direction--approximately 15-18 seconds to rotate the carrier 88 from idle position to wide-open-throttle position as compared to about 3 seconds to rotate it from wide-open-throttle to idle position. The slower speed is accomplished by the circuitry of Fig. 6, which shows in schematic detail the changes and additions to the circuitry of Fig. 5--the portions of Fig. 5 which are not repeated in Fig. 6 are identical in both circuits. The additional resistor R20 in the connection between the transistor Q3 and the motor 132 serves to reduce the voltage supplied to the motor, and with the resultant reduced speed, it is desirable that, upon arrival of 'he carrier contact 30 128 at the reference contact 116 subsequent to actuation of the governor 90, that the contact 128 should remain at the reference ~5~
contact so long as the engine speed remains in the ~000-4300 RPM
range. Therefore, the pln 13 of the noryate IC3-4 is now connected to limiting circuitry comprising the trans~stors Q4, Q5, and Q6 and their associated added components. Now, when the contact 128 touches the contact 116, the motor 132 is turned off, and so long as the engine speed remains in the 4000-4300 RPM range, it remains off. If the engine speed drops below 4000 RPM, the governor com-parator IC2-3 will cause the motor 132 to run in open throttle direction (at the slow speed) until the engine again rises to 4000 rpm, or until the carrier 88 moves in open throttle direc-tion sufficiently for the carrier contact 128 to cross the narrow gap 122 and touch the limiting contact 120 on the switch plate 92--in either case, the open throttle drive ceases; and in the first case the governor comparator IC2-3 causes the motor 132 to drive in the close throttle direction, while in the second case the carrier contact 128 remains at the limiting contact until the engine either rises to 4000 RPM and the governor comparator IC2-3 causes close throttle drive, or the engine drops below the precall speed of 3400 RPM and the precall comparator IC2-1 causes open throttle drive, carrying the carrier contact 128 past its initial contact with the limiting contact 120 toward the wide-open-throttle position of the carrier 88.
This second, slow speed, embodiment is advantageous for lessening engine speed oscillations, but is disadvantageous in that the slow travel of the carrier 88 toward open throttle may sometimes handicap the operator who is trying to get a rapid acceleration of the engine for shifting gears.
Yet a third embodiment of my engine speed governor inven-tion provides for normally fast travel of the carrier 88 toward its reference position upon actuation of the engine speed governor 90 untll the carrier contact 128 moves off the limiting con-tact 120, at which the motor 132 drops to a very slow speed resulting in clockwise movement of the carrier 88 about its shaft 94 at the rate of about one-third RPM, which would be rouyhly equivalent to full travel from wide-open-throttle position to idle throttle position in about thirty seconds. An objective of this slow speed is to move the carrier 88 in limiting control of 'che throttle plate 35 at a slower rate than the response capability of the engine 20, thereby minimizing engine speed oscillations. Since the response capability of the engine will vary considerably according to loads and gear ratios, recovery time (from the loss of engine speed due to sudden application of a heavy load while running at the governed speed under light load) could be somewhat slow--however, this is not the usual condition and is overweighed by the stability of the system for normal operation.
The relation of engine response capability rate and throttle limiting means movement rate is a complex one, but consider that any engine running at idle speed and having full throttle suddenly applied will take a second or two to reach a speed of say 4000 RPM, and if a governor acts to close the throttle quickly to closed or idle throttle position upon attainment of the 4000 RPM speed, the engine speed will overshoot or overrun the 4000 RPM speed and then decelerate below the 4000 RPM speed and undershoot or underrun it, even though the governor acts to open to full throttle again immediately upon the speed dropping below 4000 RPM. This may cause oscillations of engine speed of 1000 RPM or more in an unloaded engine, rapidly enough to be disturbing to its operator, and resulting in a governor with very poor regulation. This is an example of a throttle limiting means moving at a very much faster rate than the engine response capa-bility rate, and results in out-of-phase operation of engine and 6~
throttle as explained in my aforesaid ~ patent a~ ~a~n.
~ .
On the other hand, it has beell found tha-t where the throttle can only be moved between idle and full positions over a period of about twenty seconds or more, then in-phase operation of engine and throttle occurs, as in the present invention, and very good governor regulation can be obtained. The engine has the capability of increasing its speed with very little lag behind the throttle position, even under heavy or full load, meaning that if the throttle is opened half-way at this slow rate or slower, that the engine will have come up in speed slowly with the slow opening and will have achieved its maximum sustained speed for this throttle opening and particular load momentarily after the throttle movement stops, and will overrun the aforesaid maximum sustained insignificantly, thereby staying essentially in phase with the throttle, even under no load conditions. In the commercial engine application range considered so far, an approximately twenty to twenty-five second throttle movement period seems about the optimum for satisfactory governor regula-tion for a smoothly operating governor and a period as short as seven or eight seconds causes objectionable oscillations. Of course, to obtain satisfactory restraint under no load engine run-up conditions and satisfactory recovery from sudden load applications, it is desirable to have fast throttle closing upon sudden acceleration of the engine, and fast throttle opening upon sudden deceleration. The apparatus of the present invention provides such capability for both fast and slow throttle movement through the use of a reference position for the throttle limiting means, such that throttle movement will be slow under normal conditions, but may be swift when needed for recovery of control of a rapidly fluctuating engine speed caused by some factor external to the governor. To date, the apparatus of the present invention is the only known solution to this problem for every-day commercial use, e.g., as for truck and bus engines. Upon arrival at its reference posltion, assuming that the engine speed still lies in the A000-4300 RPM range, the carrier stops and remains in place, moving therefrom only upon detection of engine speed outside the 4000-4300 RPM range, and only at the above-mentioned slow speed, whether in open throttle or close throttle direction.
When the engine speed drops below 4000 RPM, the motor 132 is energized at the slow speed in open throttle direction and continues in that direction until the carrier contact 128 hits the limiting contact 120 and halts there, unless in the meantime the engine speed has risen again to 4000 RPM to cause the motor 132 to be reversed to close throttle direction, or has dropped below the 3400 RPM precall speed which will cause the carrier 88 to continue to open throttle direction, but at high speed a~ter touching the contact 120. If the carrier contact 128 is halted upon touching the limiting contact 120, it remains there pending detection of engine speed rising to 4000 RPM to cause close throttle drive at the slow speed, or engine speed falling below the 3400 RPM precall speed to cause open throttle drive just as in the second embodiment; however, the motor 132 will return to its normal fast speed because the carrier contact 128 is contact-ing the limiting contact 120.
As a practical matter, on a long steep grade in a truck engine application, where a considerably open throttle position is required to maintain the engine at the 4000 RPM
governed speed, after the throttle limiting means has been moved to the reference position, then the governor will allow the 5~
throttle to slowly open farther to a poin-t where its average position ~urnishes just the fuel needed to maintain 4000 RPM with only minor oscillations thereabout as the throttle is opened and closed slightly by governor detection of engine speed falling below 4000 RPM and then rising back to that speed.
The circuitry for obtaining the slow-motor speed in both directions, and only when the carrier contact 128 is out of contact with the limiting contact 120, comprises essentially a suitable resistor R31 placed in the 12 volt common supply connec-tion to the motor 132 as shown in Fig. 7 in partial schematicdetail. The resistor R31 reduces the voltage across the motor 132 sufficiently to cause it to run at the desirable low speed in close throttle direction where the force of the load speed governor spring 142 and throttle apparatus springs must be overcome, and a second resistor R30 in the open throttle connec-tion between the transistor Q3 and the motor 132 reduces the voltage across the motor even farther to compensate for the over-running ~orce applied by the governor spring 142 and throttle apparatus springs when the motor runs in throttle opening direc-tion. A PNP transistor Q7 is connected in parallel with theresistor R31 and is controlled indirectly through additional circuitry (not shown) associated with the limiting contact 120 by the condition thereof. When contact 120 is grounded by contact with the carrier contact 128, the transistor Q7 is caused to be conductive, the resistor R31 is shunted out of the circuit and is of no effect, and the motor 132 runs at normal fast speed.
When the carrier contact 128 leaves the limiting contact 120, leaving it ungrounded, then the transistor Q7 goes non-conducting and all current to the motor 132 must pass through the resistor 31, so that the motor runs at the desirable slow speed.
This third, slow speed, embodiment lessens the oscilla-tions of engine speed, and would be preferable to the first, alternating circuit, embodiment except that the low motor voltages required to obtain a sui-tably slow operation of the motor 132 may not provide sufficient starting torque for reliable motor operation under extreme cold weather conditions. However, gover-nors 30 according to this third embodiment have worked satis-factorily in moderate temperature conditions and commercially demonstrate the advantages of slow speed operation of the motor 132.
Control of the motor 132 by the load speed governor 86 (through movement of the carrier 88 and its open throttle and close throttle contacts 134 and 136 respectively, by action of the flyball mechanism 146 to move the grounding contacts 138) is the same as that disclosed in my aforementioned prior patent application, whereby the load speed governor can overridingly run the moto~ 132 in close throttle direction in response to suit-ably high load speed at any time, and the engine speed governor 90 can do likewise at any time in response to a suitably high engine speed, but the load speed governor can only run the motor 132 in open throttle direction in response to a suitably low load speed when the engine speed governor 90 is also calling concurrently for the motor to operate in that direction in response to a suitably low engine speed by making the transistor Q3 conductive, and vice-versa.
The present invention has been described in detail above for purposes of illustration only and is not intended to be limited by this description or otherwise to exclude any variation or equivalent arrangement that would be apparent from, or reasonably suggested by, the foregoing disclosure to the skill of the art, such as the substitution of vacuum or mechanical or other actuators, or the electrically driven lead screw dis-closed herein, the substitution of centrifugal or magnetic or other engine speed responsive means for the electronic module disclosed herein, or the substitution of magnetic or electronic or other load speed responsive means for the fly ball mechanism disclosed herein. I.e., the scope of the present invention is to be determined by the scope of the appended claims.
Claims (13)
1. A speed limiting governor for use with an engine having a throttle means mechanically movable between an open position and a closed position to regulate the flow of energy-supplying means to said engine, said governor comprising a) means for sensing the speed of said engine;
b) means adapted to be connected to said throttle means for selectively overriding said mechani-cal operation thereof, said overriding means being movable in a first direction toward a closed throttle position and in a second direc-tion toward an open throttle position, and being movable to a predetermined reference position intermediate said open and closed throttle positions; and c) control means responsive to said speed sensing means for moving said overriding means in said first direction to said predetermined reference position when said engine speed reaches a first preset level.
b) means adapted to be connected to said throttle means for selectively overriding said mechani-cal operation thereof, said overriding means being movable in a first direction toward a closed throttle position and in a second direc-tion toward an open throttle position, and being movable to a predetermined reference position intermediate said open and closed throttle positions; and c) control means responsive to said speed sensing means for moving said overriding means in said first direction to said predetermined reference position when said engine speed reaches a first preset level.
2. A speed-limiting governor as defined in claim 1 and further characterized in that said control means is respon-sive to said speed sensing means for moving said overriding means alternately in said second and first directions when said engine speed is within a preset range after said overriding means reaches said reference point.
3. A speed-limiting governor as defined in claim 1 and further characterized in that said overriding means is movable within a predetermined reference zone adjacent said reference position and intermediate said open and closed throttle positions thereof, and in that said overriding means moves at a relatively slow rate of movement during its movement within said predetermined reference zone and at a relatively fast rate of speed during its movement beyond said predetermined reference zone.
4. A speed-limiting governor as defined in claim 1 and further characterized in that said control means is respon-sive to said speed sensing means for moving said overriding means away from said reference point in said second direction when said engine speed falls below said preset speed.
5. A speed-limiting governor as defined in claim 4 and further characterized in that said control means moves said overriding means away from said reference point in said second direction at a rate of movement which is slower than the rate of movement of said overriding means when it moves in said direction.
6. A speed-limiting governor as defined in claim 5 and further characterized in that said control means causes said overriding means to continue moving away from said reference position at said slower rate of movement until said engine speed again exceeds said first preset level or until said overriding means has moved beyond a predetermined reference zone adjacent said reference point, whichever occurs first.
7. A speed-limiting governor as defined in claim 6 and further characterized in that said control means causes said overriding means to stop after moving beyond said pre-determined reference zone until said engine speed exceeds said first preset level and said control means causes said overriding means to move in said first direction, or until said engine speed falls below another preset level that is below said first preset level and said control means causes said overriding means to move in said second direction.
8. A speed-limiting governor as defined in claim 1 and further characterized in that said control means is respon-sive to said speed sensing means for moving said overriding means to said predetermined reference position and for causing it to cease further movement as long as said engine speed remains within a predetermined speed range above said first preset level.
9. A speed-limiting governor as defined in claim 1 and further characterized in that said control means is respon-sive to said speed sensing means for moving said overriding means away from said reference position in said first direction when said engine speed exceeds a second preset speed higher than said first preset speed.
10. A speed-limiting governor as defined in claim 1 and further characterized in that said control means is responsive to said speed sensing means for moving said overriding means in said first direction to said predetermined reference position when said engine speed accelerates from one speed level to another speed level within a predetermined amount of time, said one speed level and said another speed level both being below said first pre-set speed level.
11. A speed-limiting governor for use with an engine having mechanically operated throttle means movable between a fully opened position and a fully closed position, said governor comprising:
a) means for sensing the speed of said engine, b) means adapted to be connected to said throttle means for selectively overriding said mechani-cal operation thereof, said overriding means being movable between an open throttle position and a closed throttle position and being movable within a predetermined reference zone inter-mediate said open throttle position and said closed throttle position; and c) control means responsive to the speed of said engine and operable to move said overriding means at a relatively slow speed during move-ment thereof in said predetermined reference zone and at a relatively fast speed during movement thereof outside of said predetermined reference zone.
a) means for sensing the speed of said engine, b) means adapted to be connected to said throttle means for selectively overriding said mechani-cal operation thereof, said overriding means being movable between an open throttle position and a closed throttle position and being movable within a predetermined reference zone inter-mediate said open throttle position and said closed throttle position; and c) control means responsive to the speed of said engine and operable to move said overriding means at a relatively slow speed during move-ment thereof in said predetermined reference zone and at a relatively fast speed during movement thereof outside of said predetermined reference zone.
12. A speed-limiting governor as defined in claim 11 and further characterized in that said relatively fast and slow speeds of movement of said overriding means are both constant.
13. A speed-limiting governor for use with an engine having throttle means movable between an open position and a closed position, said governor comprising means for sensing the speed of said engine, and throttle overriding means operatively associated with said speed sensing means for selectively engaging said throttle means to automatically move it toward said closed position thereof at a first relatively fast rate of movement when the speed of said engine exceeds a preset level and said throttle means is open beyond a predetermined reference zone intermediate said open and closed positions of said throttle means, and for controlling the movement of said throttle means in either a throttle opening or throttle closing direction to provide a second relatively slow rate of movement therefor when said throttle means is within said reference zone and is engaged by said overriding means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US3606479A | 1979-05-04 | 1979-05-04 | |
| US36,064 | 1979-05-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1151961A true CA1151961A (en) | 1983-08-16 |
Family
ID=21886416
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000350698A Expired CA1151961A (en) | 1979-05-04 | 1980-04-25 | Engine governor with reference position for throttle limiter |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1151961A (en) |
-
1980
- 1980-04-25 CA CA000350698A patent/CA1151961A/en not_active Expired
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