Internal-combustion engines – Engine speed regulator – Open loop condition responsive
Utility Patent
1999-07-23
2001-01-02
Yuen, Henry C. (Department: 3747)
Internal-combustion engines
Engine speed regulator
Open loop condition responsive
C123S399000
Utility Patent
active
06167866
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention is directed to improvements in control devices for controlling a power of a driving engine.
Modern engine controllers control the position of the throttle valve, typically disposed in the intake system of a driving engine for varying the power, in an electrical way. To that end, a control device operating with an electric motor is provided, or in other words an electrically actuatable throttle valve position, for instance of the kind described in German Offenlegungsschrift DE-OS 36 31 283, and in U.S. Pat. No. 4,947,815. The throttle valve position shown in these references has springs, which keep the throttle valve, in the currentless state, in a predetermined position that is different from the fully closed position. The actuating drive of the throttle valve position, when the throttle valve is closed beyond this emergency air position, must bring a torque to bear in the closing position, while on opening of the throttle valve to greater opening values, it must exert a torque in the opening direction for overcoming the spring forces. In such throttle valve positions, icing of the throttle valve support can occur in special operating states. Experience tells that this happens particularly on a short trip when the intake air temperatures are low. The water escaping from the engine oil via the crank case vent, for instance, is deposited in the form of ice in the region of the throttle valve. When the driving engine is turned off in cold surroundings, the engine heat at first warms up the throttle valve position; the ice melts and then collects in the lower region of the throttle valve. There, it forms a layer of ice again. The next time the engine is started, the throttle valve is firmly frozen in its position of repose, which in the case of the above throttle valve position means its emergency air position. The torque of the actuating drive that engages the throttle valve is not sufficient in all cases to push the ice out of the way and move the throttle valve. The result is restricted availability of the overall system.
From German Offenlegungsschrift DE 37 43 309 A and from U.S. Pat. No. 5,078,110, it is known in this connection to detect icing of a throttle valve from an increase in the difference between a set-point and actual values of a control variable for the throttle valve. If such icing is detected, then the control unit that controls the throttle valve turns the actuating drive on and off, or the actuating drive is triggered in such a way that it generates a reversing torque. In this way, the throttle valve is intended to be torn away and the icing is meant to be eliminated. It has also already been proposed that the throttle valve be made capable of moving using a shaking mechanism similar to a percussion drill. In a percussion drill, the shaking takes place in the direction of the pivot axis. However, it has been found that this proposal is not feasible in a control device for controlling the power of a driving engine, because the control element that determines the power of the engine must be built in with very narrow play. Particularly when the control element is a throttle valve, however, even the least jarring motion along the throttle valve shaft is impossible, because of the installation conditions required.
In German Patent Disclosure DE-A 41 35 913 and U.S. Pat. No. 5,285,757 it is proposed that in principle the throttle valve be triggered before starting, in such a way that it passes through its entire range of motion, in this way eliminating dirt and other things that can cause the throttle valve to seize. Yet even in this proposal, the actuating drive is incapable of adjusting the control element if the motion resistance at the control element is greater than the torque brought to bear by the actuating drive.
In European Patent Disclosure EP 0285 868 A1 published by the European Patent Office and in U.S. Pat. No. 4,823,749, it is proposed that if the throttle valve is solidly frozen, the field vector of the actuating drive be made to rotate at a frequency near the resonant frequency of the mechanical system. The resultant jarring motion is intended to break the throttle valve free. However, if it is solidly frozen, the throttle valve cannot move at all, and thus no jarring motion can be expected even if the field vector does rotate.
OBJECTS OF THE INVENTION
It is a principal object of the invention to overcome the above-described disadvantage and to increase the availability of the control device.
It is a further object of the invention that even a relatively firmly stuck control element can be torn loose, because when the control element is stationary the drive element can lift away from it and then, after a reversal of the direction and motion, can strike the control element with dynamic force. Advantageously, even a relatively weak actuating drive can therefore be used without impairing the functional safety and reliability. The proposed invention is especially helpful whenever no torque step-up gear is provided between the actuating drive and the control element.
It is yet another object of the invention that by means of the second drive stop on the drive element and the second control element stop on the control element, the advantage is obtained that the dynamic force of the drive element can act on the control element in both directions of motion. The advantageous result is that the control element is especially effectively jarred loose.
It is still another object of the invention that because of the two stops each on the drive element and the control element, the drive element is never adjusted beyond a certain amount in the direction of reducing the engine power without the control element necessarily going along with this motion.
It is yet an additional object of the invention to provide a detent device acting between the control element and the drive element having the advantage of assuring that the control element goes along with the motion of the drive element. This advantageously assures that even if flow forces, for instance, engage the control element, which for instance is a throttle valve, the control element cannot unintentionally lift away from the drive element. Typically, a restoring spring acting between a housing and the control element is provided. However, in the direction of lesser power of the engine, this restoring spring has a weaker action than in the range of high power of the engine. If the detent device were not present, then the restoring spring would have to be made strong enough that even in the range of low power of the engine, the force of the restoring spring would suffice for securely positioning the control element. The detent device at least partly takes on the task of making the control element reliably follow the motion of the drive element, so that the restoring spring can be designed with weaker force and thus advantageously can be smaller in size. This has the further advantage that the actuating drive only needs to counteract a restoring spring that is not as strong, so that the actuating drive can be still weaker and thus even more economical.
SUMMARY OF THE INVENTION
The detent device can advantageously be created very simply and without major effort with the aid of the magnetic force of one or more magnets that actuate the control element toward the drive element.
The actuating drive typically has one magnet. If the magnetic force of this magnet is employed such that at least some of the magnetic force assures an actuation of the control element toward the drive element, then the detent device can be furnished without any significant additional expense.
The coupling spring between the drive element and the control element advantageously, without major effort, assures reliable coupling of the motion of the control element with the motion of the drive element.
With the emergency spring, which keeps the control element in an emergency position by way of the drive element, the advantage is obtained that even if the actuating drive fails, continued operation of the
Hammer Uwe
Jakisch Thomas
Greigg Edwin E.
Greigg Ronald E.
Robert & Bosch GmbH
Vo Hieu T.
Yuen Henry C.
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