METHOD AND SYSTEM. OF ELECTRONIC OPERATION OF DEGRADED CHOKE
BACKGROUND OF THE INVENTION The present invention relates to torsion engines. Motors of this type typically provide displacement or angular movement of a rotor in a magnitude proportional to the characteristics of an electrical signal applied to the motor windings. For example, the angular movement can be proportional to the voltage applied to the motor winding. Torsion motors have found widespread application in various control systems. In these systems, it is desirable to rotate an arrow to a specific position or apply a specific amount of torque to an arrow in response to an electrical control signal. In a particular system, it has been desirable to use a torsion motor to control the position of a throttle plate within an internal combustion engine. Such a system is disclosed in U.S. Patent Application Serial No. 09 / 076,352, assigned to the assignee hereof, and incorporated herein by reference, and is directed to break ice within a choke assembly after of a period of non-use. Other such systems control the position of the air intake throttle valve by means of an electrical signal during the operation of the engine. In relation to controlling the position of the throttle plate in a running engine, the old systems were mechanically controlled by means of movement of the user of a throttle link attached to the throttle valve. On the other hand, electrical control of the throttle valve is especially desirable in certain applications of motor vehicles such as to provide cruise control and / or to overcome the user input to the throttle position control mechanism in response to conditions extreme driving or emergency situations. For example, where an antilock brake system, traction control system or bypass rate control system is used in the vehicle, it is desired under certain conditions to have an electronic control system that determines the position of the choke, rather than the operator. However, there is a disadvantage with respect to electrically controlled throttling systems. Namely, if the electrical system of the vehicle fails, or if the electric power to the throttle motor is interrupted, the electrical signal that controls the choke position of the vehicle disappears, causing the throttle valve to "float." in the matter that a floating choke can be opened further, thus accelerating a vehicle unexpectedly or dangerously.In recognition of this hazard, throttling control systems typically include springs for closing a throttle valve in the absence of opening torsion provided by The throttle controlling mechanism or motor, however, this spring closing feature results in an air flow that is abruptly reduced to the vehicle engine, causing the vehicle to slow down and eventually stop, perhaps in traffic, again placing potentially to occupants and vehicles The present invention contemplates a new, more secure electronic bottleneck and method of use, which overcomes the aforementioned problems and others. SUMMARY OF THE INVENTION In accordance with the present invention, a method of ensuring continuous air flow to a motor controlled by an electronic throttling system during a time of loss of electrical energy is provided. The method includes the steps of placing a choke plate within an air / fuel intake manifold such that the choke plate is movable between an open position which allows the flow of air through the manifold and a closed position that substantially blocks the air flow. Also included is the application of a first twist to the throttle plate to urge the throttle plate into the open position and the application of a second twist by urging the throttle plate to the closed position. The first and second twists counter each other so that the throttle plate remains in a position between the open and closed positions to allow air flow through the manifold. According to another aspect of the present invention, the first torsion is provided by the electromagnetic properties of a torsion motor and the second torsion is provided by a return spring. According to a more limited aspect of the present invention, the method further includes determining a reluctance torsion curve by plotting a specific value of reluctance torsion for a range of positions of the throttle plate. Then the choke plate is aligned such that the reluctance torque value for a desired position cancels the closing bias at the desired position. In this desired position, the throttle plate is sufficiently open to provide air flow through the manifold to the engine. In accordance with a further aspect of the present invention, there is provided a method of configuring an electronic throttle assembly to operate in a degraded mode without electrical power. An opening torsion is applied to a throttle plate tending to urge the throttle plate to an open position, allowing the flow of air through a manifold. Simultaneously, a closing twist is applied to the throttle plate tending to urge the throttle plate to a closed position. The simultaneous applications of opposite torsion leave the throttle plate in a neutral, slightly open position. According to another aspect of the present invention, the opening torsion is applied by steps including connecting the throttle plate to a rotating portion of an electromagnetic torsion motor. The torsion motor defines a plurality of reluctance torsion values based on the position of the rotating portion. The throttle plate is placed in a displaced position, allowing the reluctance torsion to provide the opening torsion. According to another aspect of the present invention, an electronic throttle includes a throttle plate movably disposed within an air / fuel intake manifold. The choke plate travels between a first position substantially blocking the air flow and a second position substantially allowing air flow. A torsion motor defines a first variable torque that urges the throttle plate to the second position when no current flows through the motor windings. Conversely, means are also included to provide a second twist that tends to urge the β-throttle plate towards the first position. An arrow is also included in operative connection between the torsion motor and the throttle plate. The arrow is angularly aligned such that the throttle plate rests in an equilibrium position between the first and second positions. According to a more limited aspect of the present invention, the first variable torsion is produced by the electromagnetic properties of the torsion motor. According to a more limited aspect of the present invention, the means for providing the second twist are a return spring. An advantage of the present invention resides in the provision of a method that ensures the continuous flow of air to a motor during periods of power failure. Another advantage of the present invention is the provision of a method that configures an electronic throttling assembly in a manner that allows degraded operation in the absence of electrical power. Other benefits and advantages of the present invention will be apparent to those skilled in the art upon reading and understanding the detailed description of the preferred embodiments. Brief Description of the Drawings The invention may take form in certain parts and arrangements of parts, and in certain steps and arrangements of steps, embodiments of which are illustrated herein. The drawings are solely for the purpose of illustrating preferred embodiments and should not be construed as limiting the invention. Figure 1 is a simplified diagrammatic illustration of an internal combustion engine air intake system for a motor vehicle and the associated electronic throttle control system; Figure 2 is a graphical representation of the variance of the torque measured against the throttle position. Detailed Description of the Invention Referring to Figure 1, a simplified internal combustion engine includes an air / fuel intake manifold I. The air enters the manifold I through the AF air filter. The air flow to and through the manifold I is controlled by a throttle plate valve T. The throttle plate valve T selectively locks the air flow in one position or is rotated in a variant amount, allowing passage of a selected air flow to the internal combustion engine E. A fuel injector F selectively injects gasoline or other fuel into the air stream for combustion in the engine E. The angular position of the throttle plate T is controlled by the engine of 10. In particular, the output shaft 12 of the motor 10 is connected to the throttle plate T so that the plate rotates at the request of the motor 10. The torsion motor 10 receives electric power 14 and command signals 16. It will be recognized by those skilled in the art that if energy is lost in the torsion motor 10, the desired positioning by the operator of the throttle plate T is lost. In this manner, an operator of a vehicle will be unable to control the speed of the internal combustion engine E. Referring now to Figure 2, the graph 20 sketches the torsion on the vertical axis 22 and is measured in ounces-inch (oz. -in) The throttle position on the horizontal axis 24 is sketched in terms of degrees of rotation of the throttle plate valve T. If a torsion motor winding does not carry current, the torsion curve versus position MT0 is basically zero, except in the ends. This is called "reluctance twisting" and is due to a large rate of change in stored energy as the torsion motor pole tips begin to interact with the north-south magnet transition. On the other hand, at a maximum winding current of the torsion motor, the torsion curve versus MTmax position shows almost uniform torsion in all positions, except at the ends. Also shown in Figure 2 is a return spring torsion curve 30. The reflected, negative return spring curve 32 shows a point of intersection with the reluctance torsion curve MT0. This point of intersection is the position of "residence" 34. The return effect will be increased by the displacement of the choke arrow, if used. Therefore, ignoring the friction, those skilled in the art will recognize that the choke T will remain in the residency position 34 if there is no current in the coils. The air flow may slightly urge the throttle T towards the choked throttle position 36, usually a mechanical stop. The net effect is a self-regulating throttling valve T. If the engine speed is increased, the air flow through the manifold I is increased and the throttle displacement will pull the throttle position T back, reducing the flow of air. air, reducing the speed of the engine. If the engine speed is reduced, the reduced air flow through the manifold I will allow the throttle T to open under the force of the reluctance torsion MT0, thereby increasing the engine speed. Those skilled in the art will recognize that the present development defines a self-regulating system for controlling the position of the throttle plate valve T when the electrical power is lost to the motor 10. With continued reference to FIG. 2, position 38 defines a fully open position for the throttle valve T. Accordingly, the throttle valve is movable between the first and second positions 36, 38, which are each defined by mechanical stops to prevent movement of the throttle plate T beyond them. Normal operation with positive current generates additional torque MTmax on the reluctance torsion MT0. Thus, the mechanism of the choke plate T will open. Or, in other words, the throttle plate will move along the throttle position axis 24 away from the closed position 36 towards the fully open position 38. The effective torque of the engine on the throttle plate can be seen as the difference between the positive motor torque (e.g., MTm.) and the curve of the reflected return spring 32. The speed of idling below the residence position 34 is achieved by passing negative current through the windings of the torsion motor 10 to pull the torsion T towards the closed position 36, overcoming the "slope" of the reluctance torsion MT0. The gradual increase in the magnitude of the negative current will generate a torque that will pull the mechanism of the throttle plate T against the stop 36. The curve 40 sketches a torsion applied to the throttle plate T in response to a negative current passed through. of the motor windings. As is evident, the negative current is required to completely close the throttling T, exceeding the MTO reluctance torsion. In the absence of negative electric current to completely close the choke T, the operator will have to link other means of stopping the vehicle when it is safe to stop, for example, a wheel brake assembly, or a gear shift of the transmission . Although the invention has been described with respect to the illustrated embodiments, it will be understood that the invention is capable of modifications and variations and is only limited by the following claims.