US 3692007 A
There is provided means for sequentially decoupling accessory loads from an engine in such a manner that, particularly when the engine is of optimum torque or power design, the decoupling action will not cause a sudden increase in engine torque output to be applied to the driving wheels of an automobile. Decoupling of the various engine accessories can be accomplished one at a time over a given limited range of throttle or torque demand settings or can be a gradual decoupling beginning at some predetermined throttle or torque demand setting and continuing to a condition of complete decoupling.
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Description (OCR text may contain errors)
United States Patent Nilssen METHOD AND APPARATUS FOR DECOUPLING ENGINE ACCESSORIES 8/1971 Kaye ..62/243 72 Inventor: Ole K. Nilssen, Barrington Hills, in. figx2112 2 Bums  Assignee: Motorola, Inc., Franklin Park, Ill. 22 Filed: Dec. 30, 1970 [571 ABSTRACT  Appl Nu: 102,710 There is provided means for sequentially decoupling accessory loads from an engme m such a manner that, particularly when the engine is of optimum torque or  US. Cl ..l23/98, 62/243, 123/195 A, power design the decoupling action Will not cause 3 123/198 R, 192/.07, 192L0 sudden increase in engine torque output to be applied  il 12 g iq ggg to the driving wheels of an automobile. Decoupling of  0 the various engine accessories can be accomplished 192/075 62/243 one at a time over a given limited range of throttle or torque demand settings or can be a gradual  References C'ted decoupling beginning at some predetermined throttle UNITED STATES PATENTS or torque demand setting and continuing to a conditron of complete decoupling. 3,132,728 5/1964 Chaptois ..192/.O75 X 3,186,184 6/1965 Pruitt ..192/.07 2 Claims, 6 Drawing Figures 12 1 1' y l 1 I can PATENTEDSEP 1 1912 3. s92. 00 7 FIGI FIGZ
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METHOD AND APPARATUS FOR DECOUPLING ENGINE ACCESSORIES BACKGROUND OF THE INVENTION This invention relates generally to a method and apparatus for decoupling engine accessories from automobile engines, or the like.
Heretofore, decoupling of an engine accessory, as for example, the compressor of an air-conditioner, is well known and serves to provide additional engine torque to the driving wheels of the automobile. However, such decoupling of the engine driven accessories may go substantially unnoticed with respect to the increase in available engine torque, because the engines heretofore utilizing such features have been, for the most part, overpowered for the particular vehicle being propelled. For example, the large engines used in American cars are many times overpowered as compared to the actual power needed for the particular load being moved. This high powered engine design serves to provide high starting torque for fast acceleration. For example, an engine having a horse power rating of 200 horsepower or more, which is the case for many American cars, is practically unaffected by the decoupling action of an air-conditioner or other accessory load at the high speed range of the engine, and any torque increase thus produced by the decoupling action goes substantially without notice. However if the engine were designed for optimum power capabilities for high speed sustained operation without regard to the fast acceleration desired, such engine can be made relatively small and the torque increase obtained by decoupling the engine driven accessories is readily noticable as a sudden increase in speed.
In the modern trend for producing automobiles which will reduce the pollution in the atmosphere, a reduction in engine size is one positive approach of decreasing the amount of pollutants emitted by each automobile. However, by reducing the engine size the maxmium amount of torque is also reduced. Furthermore, when connecting several or more accessory units to be power driven by the engine, the available torque at the driving wheels is further reduced. It is of no consequence in most instances that the amount of torque absorbed by the accessories is not available for power at the driving wheels. That is, during normal acceleration and at moderate sustained speeds the engine has adequate power to supply all the torque necessary, and the throttling of this torque by the gas pedal or throttle control is obtained uniformly throughout the entire speed control range. However, it becomes advantageous at the high speed, or high torque requirement conditions of the engine, to disconnect certain ones or substantially all of the accessories being driven by the engine. By so disconnecting these accessories, when associated with engines of minimum power and torque capabilities, the sudden reduction in load on the engine caused by the decoupling of the accessory, will also cause a corresponding sudden increase in torque supplied to the driving wheels of the automobile. This sudden increase is a non-throttleable condition and is undesirable because there is no gradual control between the two torque conditions which exists before and after the accessory load is removed from the engme.
SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provide an improved accessory decoupling method and apparatus for disconnecting one or more engine driven accessories at predetermined torque demand conditions.
Yet another object of this invention is to provide means for decoupling a plurality of engine accessories in sequential manner so a sudden increase in torque is not delivered to the driving wheels of an automobile.
Still another object of this invention is to provide a method of decoupling engine accessories so maximum power or torque can be developed from small engines.
Briefly, the method and apparatus of this invention includes an engine, of optimum design thus being of minimum horse power, for delivering power to the driving wheels of an automobile over a wide range of speed and torque conditions beginning with an initial condition and uniformly increasing to an intermediate condition. At this intermediate condition, one or more of the various engine accessories being driven are decoupled, either sequentially in a predetermined step-by-step fashion or linearly and uniformly at a predetermined rate, to provide a controllable increase of torque supplied to the drivingwheels rather than a sudden increase. This controllable increase is at a different rate beginning at the predetermined condition and continuing at the new rate to the maximum torque available from the engine. In one arrangement there is provided a sequentially disconnectable switching device to which the respective accessories are connected to receive electrical power and are thus decoupled by the opening of different switch contacts of the device. The opening of the switch contact will de-energize a clutch or other electro-mechanical device so that during this decoupled period of time the torque which would otherwise be delivered to the engine accessory is now delivered to the driving wheels of the automobile. In the alternative, a switching device can be provided with a movable contact which moves across a short circuit bus bar and therefrom engages a resistance element uniformly to increase the resistance connected in series with the accessory energizing device ultimately to disconnect power therefrom and remove the accessory load from the engine. The plurality of accessories herein referred to may be either a plurality of different kinds of accessories or a plurality of different stages of the same kind of accessory. That is, an air-conditioner or other relatively large load device may be formed into several small sub-units of compressors which are sequentially disconnected one sub-unit at a time.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic representation of an automobile engine illustrating one embodiment of this invention;
FIG. 2 is a curve illustrating throttle setting versus torque supplied to the driving wheels of an automobile having a relatively small engine when a heavy accessory load is suddenly decoupled therefrom;
FIG. 3 is a curve illustrating the decoupling of engine accessories in accordance with one arrangement of this invention;
FIG. 4 illustrating an alternate embodiment for decoupling engine accessories in accordance with this invention;
FIG. 5 is a curve illustrating the decoupling of engine accessories in accordance with the alternate embodiment shown in FIG. 4; and
FIG. 6 illustrates another kind of switching device that can be used in accordance with this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1 there is seen an engine designated generally by reference numeral 10, and is preferably of a type used in automobiles. The engine can be either water cooled or air cooled as desired. A carburetor 12 is provided for controlling the amount of fuel delivered to the engine, thus throttleably controlling the amount of power delivered by the engine to the drive wheels of the automobile. A setting of the engine torque demand means will set the speed and torque conditions of the engine. The torque demand means is here illustrated as a gas pedal 14 connected to the carburetor 12 by a pair of rods 15 and 16 which, in turn, are interposed with a pair of links 17 and 18 so as to translate the slight movement of the gas pedal in one direction to the appropriate movement of a throttling mechanism on the carburetor 12 in another direction.
Also connected to the link 18 is a switching device designated generally by reference numeral 20. The switching device 20 is shown in a general manner and is used to sequentially disconnect the load of respective ones of a plurality of engine driven accessories. That is, a movable contactor 21 is electrically connected to a source of power, such as the battery or alternator system of the automobile, and arcuate contacts to apply energizing current to electrical and/or electromechanical coupling mechanism of the engine accessories. These electrical and/or electromechanical coupling mechanisms may be, for example, alternator field winding, clutches or solenoids, as desired. Here an arcuate contact 22 is electrically connected to the engine accessory 23 to apply energizing current thereto during movement of the gas pedal 14 from its initial power position to some intermediate power position. A second arcuate contact segment 24 is electrically connected to an accessory 25 to energize the load coupling mechanism thereof, and is correspondingly de-energized upon further arcuate movement of the contact 21 to a second intermediate position. Finally, a third arcuate contact 26 is electrically connected to the coupling device of an accessory 27. Movement of the throttle to the maximum power position will thus move the contact 21 and ultimately disconnect the last arcuate segment 26 to removing power from the accessory 27 and then all of the accessories 23, 25 and 27 will be decoupled from the engine.
The switch 20 has the arcuate contacts 22, 24 and 26 thereof insulated one from the other and mounted to the engine for physical support but also electrically insulated from the engine by any suitable stand off or support arrangement. The broken lines illustrating the movable contactor 21 in an advanced position shows the disengagement of the contactor 21 from the first arcuate contact 22 to de-energize the accessory 23. However, the switching device 20 may include a contact support which extends beyond the arcuate contacts 22, 24 and 26 so that a wiper brush arrangement on the movable contactor 21, if used, will continue to be supported while electrically disconnected from the arcuate contacts.
The engine 10 is here illustrated as being of small horse power rating, as commonly found in small compact cars and many foreign cars, and decoupling of the engine accessories will produce a substantial increase in torque delivered to the driving wheels of the automobile. This is in contrast to the larger automobiles with large and powerful engines and decoupling of such accessories has little or no noticable effect at the power train of the automobile.
- The gas pedal 14 is illustrated as only one means of setting a torque demand from an engine. Any suitable throttling or power sensing arrangement can be incorporated to operate a sequential switching arrangement and decouple the accessories 23, 25 and 27. Such decoupling may be temporary only taking effect upon the throttle passing into the various intermediate ranges and automatic means may be provided to restore electrical power to the coupling devices when the engine speed increases so that the accessories will again be driven by the engine. That is, upon acceleration of the automobile, the accessories are preferably disconnected as described above. But as the automobile comes up to speed and thus torque demands decrease, the accessories may be again connected to the engine one at a time in reverse sequence or all at the same time.
The switching device 20 may be of any suitable kind, as for example, a plurality of limit switches engaging a mechanical link at various points through its movement or it may be done electronically with sensing elements positioned on the linkage between the gas pedal and the carburetor to sense its movement.
FIG. 2 illustrates the throttle versus torque curve and is designated by reference numeral 30. This curve shows a sudden rise 31 in torque delivered to the driving wheels of an automobile when the relatively large load accessories are suddenly disconnected from the engine. This increase in torque is uncontrollable and undesirable as it is not distributed over a range of throttle settings.
FIG. 3, illustrates the throttle versus torque conditions produced by the engine and decoupling arrangement such as that shown in FIG. 1. The curve 32 continuously increases with the throttle setting to an intermediate condition 33 whereupon the first engine acc essory is decoupled and only a small portion of the torque is then applied to the driving'wheels. As the throttle is further advanced to a second intermediate position, a torque increase designated by reference numeral 34 is applied to the driving wheels. A final throttle setting will increase the torque as designated by reference numeral 35, and this condition then applies maximum torque to the driving wheels. This step-by-step function will prevent a sudden surge of torque as shown in FIG. 2.
When utilizing this arrangement, various engine accessories can be decoupled for example, an air-conditioning compressor, an electric heating alternator, the standard power and battery-charging alternator, the cooling fan, the water pump and so on. However, such accessories as designated herein may also be fractional parts of one accessory which provides a large load. For example, an air-conditioner having several small compressors rather than one large compressor can have each of the smaller compressors decoupled in a sequential manner.
Referring now to FIG, 4, there is seen an alternate embodiment of this invention and only the switching mechanism thereof is illustrated. Here a switching device 40 is shown with a movable contactor 41 engaging a stationary arcuate contact segment 42 which ultimately leads into a wire wound resistance element 43, or any other suitable variable impedance element. As the movable contactor 41, which is connected to the throttle linkage of the automobile, moves across the arcuate contact 42, full electrical power is continuously applied to the accessory or accessories through a line 45. At some intermediate position of the contact 41, electrical power through the line 45 is restricted by the amount of resistance inserted in the line as the movable contact 41 goes across the resistance element 43. This change in resistance thus decreases the amount of load being absorbed by the accessory, this being true in the case in an alternator or generator arrangement wherein excitation current is supplied through the switching device 40, so that the torque delivered to the driving wheels gradually increases. This is best illustrated in FIG. 5 which shows a throttle versus torque curve 50 and at an intermediate position 51, this point corresponding to the point where movable contact 41 initially engages the resistance element 43, the torque delivered to the driving wheels increases uniformly with gas pedal movement but at a different rate as indicated by the line segment 52. This arrangement has particular utility when disconnecting, for example, an alternator by merely decreasing the amount of power delivered to the excitation winding of the alternator. Thus, reducing the excitation current to the alternator by increasing the series resistance therewith will reduce the amount of torque absorbed by the alternator and this torque is delivered to the driving wheels of the automobile.
Seen in FIG. 6 is an alternate form of switching device which can be used in accordance as part of the apparatus of this invention. The switching device may be mounted to any suitable support on or near the engine 10 and it has a shaft 60 for rotation in the direction of the arrow. Upon actuation of the accelerator pedal 14, and through appropriate linkages, the shaft 60 rotates an insulated body 62 secured thereto which, in turn, has a radially outwardly conductive segment 64. The conductive segment 64 engages a series of stationary contacts 66, 68 and 70 which are arranged for connection to the accessories 23, 25 and 27, respectively. As the trailing edge 64a of the conductive segment 64 disengages the stationary contacts, the accessory connected to the respective contact is de-energized and the load thus removed from the engine. Many other suitable switching arrangements may be incorporated to form the features f this invention.
What has been described is a simple and effective means for sequentially or uniformly removing the load of engine accessories from mechanical connection with the engine during certain load demand conditions so that the torque which would otherwise b3 absorbed b these accessories is now available at the r1 vmg whee s of the automobile to provide additional power for acceleration. Such decoupling action, either the sequential step-by-step function or the linear function, is substantially uniform of the range of decoupling. Accordingly, variations and modifications of this invention may be affected without departing from the spirit and scope of the novel concepts disclosed and claimed therein.
1. A method of decoupling a plurality of individual engine accessory means from an engine which is to operate over a wide range of engine speeds under various torque conditions, comprising the steps of, setting of a torque demand means to select the desired engine speed and torque conditions, said speed and torque conditions being uniformly variable over a range beginning from its initial condition and continuing until the engine produces maximum deliverable torque, step-by-step decoupling of a plurality of said individual accessory means each at a different time sequence beginning at said initial condition and continuing such step-by-step decoupling action until all engine accessories that are to be decoupled are in fact decoupled and the engine produces maximum deliverable torque.
2. An apparatus for decoupling engine accessory means comprising in combination an engine for delivering power over a range of speed and torque conditions beginning with an initial condition and uniformly variable to an intermediate condition, a torque demand means selectively to increase engine power uniformly through the entire range of speed and torque conditions, a switching mechanism connected to said torque demand means for switchably disconnecting respective different ones of the accessory means in a predetermined sequence beginning at said intermediate condition and continuing to a maximum speed and torque condition, and decoupling means responsive to said switching mechanism for gradually decoupling engine accessory means until all such accessory means that are to be decoupled are in fact decoupled thus allowing the engine to produce maximum torque.