EP0488016B1 - Device for controlling the power output of an internal combustion engine, particularly for motor vehicles - Google Patents

Description

The invention relates to a device for controlling the power output of an internal combustion engine, in particular for motor vehicles, with an accelerator pedal that is mechanically operatively connected to an electrical setpoint generator, with a throttle valve influencing the power output of the internal combustion engine, which is rotatably arranged in a throttle valve neck and by a return spring is loaded against the open position, with an electrical actuator that is mechanically operatively connected to the throttle valve and with an electrical control unit to which the electrical signals of the setpoint generator are fed as input signals and which, depending on the input signals, generates an output signal that is fed to the electrical actuator .

Such a device is previously known from DE-PS 27 14 113 or WO 88/02064. The device there enables the synchronous transmission of motion between the accelerator pedal and the throttle valve without mechanical means such as a linkage, a Bowden cable or the like. In order to ensure that in the event of a failure of the device, the throttle valve is not pivoted into a full throttle position or, if it is in the full throttle position, remains in this position, the device there has a coupling which provides the mechanical operative connection between the throttle valve and the electrical actuator interrupts if the device has an error. This measure is intended to pivot the throttle valve back into its rest position by means of spring force, as a result of which the engine falls back to its idling speed.

However, this known device has disadvantages. Characterized in that the throttle valve is pivoted back into its rest position by the spring force, the internal combustion engine will usually not fall back to its idling speed, but will rather die off, since today the throttle valves usually seal against the throttle valve body in the fully closed position of the throttle valve so well that those that continue to pass through Residual air is not sufficient to keep the internal combustion engine running. This has the consequence that the internal combustion engine dies and an emergency operation of the motor vehicle is no longer guaranteed in the event of a malfunction of the device.

If the idle position of the throttle valve in the previously known device does not correspond to the fully closed position of the throttle valve in the throttle valve connection piece, so that the internal combustion engine actually runs in idle position when the throttle valve is idle, the other problem arises that with the previously known device the control quality normally required today is not can be achieved. That is, if the throttle valve cannot be fully closed, additional functions that are commonly used in such devices are nowadays such as, for. B. the idle speed control of the internal combustion engine, not feasible.

In addition, the clutch required in the known device between the actuator and the throttle valve is a mechanically complex part, which makes the known device expensive to manufacture and cost.

The present invention has for its object to provide a device for controlling the power output of an internal combustion engine, in particular for motor vehicles, in which a purely electrical connection between the accelerator pedal and the Throttle valve is provided and which enables a safe emergency operation of the internal combustion engine even in the event of a malfunction of the device according to the invention in a simple and inexpensive manner.

This object is achieved in that the throttle valve is arranged in the throttle valve neck such that it can rotate beyond the fully closed position that a stop element is provided which is mechanically operatively connected to the throttle valve, and that a stop is provided with which the stop element can be brought into contact in such a way that the throttle valve is in an emergency running position beyond the normal open position beyond the normal open position.

The fact that the throttle valve is arranged in the throttle valve neck in such a way that it can turn beyond the fully closed position ensures that the control device can adjust the throttle valve in accordance with other functions in addition to the throttle valve adjustment proportional to the position of the accelerator pedal. These functions may include e.g. B. to the idle speed control or traction control. If necessary, the throttle valve can be moved into the fully closed position, so that the power output of the internal combustion engine can be reduced to almost 0 without further measures. The necessary emergency operation of the internal combustion engine, especially when used in motor vehicles, is ensured according to the invention in that a stop element is provided which is mechanically operatively connected to the throttle valve and in that a stop is provided with which the stop element can be brought into contact in such a way that the Throttle valve is in an emergency running position beyond the fully closed position beyond the normal opening position. Through the the latter measures, the throttle valve is pressed by the return spring through the stop element onto the stop when a malfunction of the device according to the invention is determined and when the electrical control device is consequently switched off and the electrical actuator is switched off. In this case, however, the throttle valve is not in a rest position which corresponds to the fully closed position of the throttle valve, as in the prior art, but in an emergency running position which differs from the fully closed position and which is in the direction of rotation beyond the normal open position of the throttle valve.

In this emergency running position, a predetermined minimum air throughput of the internal combustion engine is guaranteed, which, for. B. may correspond to an increased idle speed of about 1200 revolutions / minute. This minimum air flow is z. B. achieved by an open position of the throttle valve in the emergency running position of about 5 degrees. With this increased idle speed of the internal combustion engine, the motor vehicle can still be driven in an emergency mode without the internal combustion engine dying, as must be feared in the prior art.

Another advantage of the device according to the invention is that the possible turning of the throttle valve beyond the fully closed position during operation of the device according to the invention prevents the throttle valve from jamming or biting. In addition, when the internal combustion engine is switched off, the throttle valve is likewise moved into the emergency running position by the return spring, so that even when the internal combustion engine is switched off, the throttle valve is in a predetermined position which enables ventilation of the intake tract of the internal combustion engine, so that no gasoline vapors can possibly remain there when restarting the Internal combustion engine can lead to malfunctions of the internal combustion engine.

Finally, the device according to the invention is simple and inexpensive to manufacture and mountable in the motor vehicle, since it is not necessary, as in the prior art, to provide a complex coupling arrangement, but rather a simple stop arrangement is sufficient.

Advantageous refinements and developments of the device according to the invention result from the subclaims.

In order to enable a clear differentiation of the normal function of the device according to the invention from the emergency operation function, it is particularly advantageous if the control unit controls the actuator in both directions of rotation of the throttle valve in such a way that the throttle valve moves in a normal function range against the force of the return spring when the encoder is functioning properly emotional. This normal functional range is then limited by the fully closed position of the throttle valve and by one of the two fully open positions of the throttle valve, which is in the opposite direction to the emergency running position. The throttle valve is then moved beyond the fully closed position into the emergency running position only when the device according to the invention is in emergency operation.

To avoid damage to the throttle valve and the throttle valve connector when the control unit is switched off in the event of a malfunction and thus when the actuator is de-energized, it is particularly advantageous if the stop has a stop spring, the spring force of which is directed counter to the return spring and whose spring force is applied when the stop element is in contact the attack is greater than the spring force of the return spring. These measures intercept when the actuator is de-energized and when the throttle valve accelerates towards the fully closed position by the return spring, the impact of the stop element on the stop by the stop spring, so that bending or even destruction of parts of the device according to the invention is avoided. However, in order to avoid an undesired movement of the throttle valve beyond the emergency running position in the event of emergency running, the spring force of the stop spring when the stop element rests against the stop must be greater than the spring force of the return spring.

In order to enable not only the described emergency operation of the internal combustion engine but a more comfortable emergency operation of the internal combustion engine in the event of a malfunction of the device according to the invention, it is particularly advantageous if the control unit controls the actuator in a direction of rotation of the throttle valve in the event of a malfunction of one or more sensors the throttle valve is moved in an emergency function area against the force of the stop spring. That is, if such a malfunction of one or more sensors is determined by the control device, the control device is not completely switched off, but rather the control device controls the actuator only in one direction of rotation of the throttle valve, namely in the normal closing direction of the throttle valve. By means of this measure, the throttle valve can then be moved beyond the emergency running position against the force of the stop spring by means of the actuator, so that the throttle valve can be opened further in this emergency function area. This measure is particularly advantageous if, in addition to the one electrical setpoint generator, a second electrical setpoint generator or an idle switch may also be provided on the accelerator pedal, which are still functional if one setpoint generator fails. Even if all electrical setpoint transmitters except for the If the idle switch is to be defective, the control unit can still use the idle switch to determine whether the accelerator pedal is in the idle position or not. As soon as the driver of the motor vehicle actuates the accelerator pedal from the idle position, the control device can then actuate the actuator in a predetermined manner in order to open the throttle valve further beyond the emergency running position and to increase the speed of the internal combustion engine. In this case, the throttle valve can be set at an angle of 10 to 15 degrees, which then corresponds to an idling speed of the internal combustion engine of around 3500 to 4000 revolutions and which is not only a makeshift but also almost comfortable driving of the motor vehicle, even in the case of partially defective ones , device according to the invention.

As already explained above, the provision of an idle switch, which is mechanically operatively connected to the accelerator pedal, is particularly useful for realizing the more comfortable emergency driving function. For the same reason, a second setpoint generator can be provided, which is mechanically operatively connected to the accelerator pedal. If one of the two setpoint transmitters malfunctions, the other setpoint transmitter is still functional and is able to forward the driver's request to the control unit.

In order to enable not only control of the throttle valve according to the accelerator pedal position, but also position control of the throttle valve by the control unit, it is particularly advantageous if one or more actual electrical value transmitters are provided which are mechanically operatively connected to the throttle valve.

The function of the transmitter can be controlled by the control unit, among other things, when the internal combustion engine is switched off be checked. In this connection, the throttle valve can be rotated by the control unit into a predetermined rotational position for this functional test without checking for dangerous driving situations of the motor vehicle, in order to check whether the measured sensor signals match predetermined target values.

In order to avoid overloading the actuator in this emergency operation mode, controlled solely by the idle switch, in particular when realizing the comfortable emergency driving function, it is particularly advantageous if the control device has an overload protection for the actuator.

An embodiment of the device according to the invention is shown in the drawings and is explained in more detail below with reference to the drawings.

• Figur 1 schematisch eine erfindungsgemäße Einrichtung zur Steuerung der Leistungsabgabe einer Brennkraftmaschine eines Kraftfahrzeuges,
• Figur 2 schematisch eine Drosselklappe in einem Drosselklappenstutzen mit einem Anschlag in der vollgeschlossenen und in der vollgeöffneten Stellung der Drosselklappe und
• Figur 3 die gleiche Anordnung wie in Figur 2 in einer Notlaufstellung der Brennkraftmaschine und in einer weiteren Notfahrstellung der Brennkraftmaschine.

Show it

• 1 schematically shows a device according to the invention for controlling the power output of an internal combustion engine of a motor vehicle,
• Figure 2 shows schematically a throttle valve in a throttle valve neck with a stop in the fully closed and in the fully open position of the throttle valve and
• 3 shows the same arrangement as in Figure 2 in an emergency running position of the internal combustion engine and in a further emergency driving position of the internal combustion engine.

In FIG. 1, an accelerator pedal (1) is spring-loaded by an accelerator pedal return spring (19) in the direction of the idling position shown. The accelerator pedal (1) has a first electrical setpoint generator (2) and a second electrical setpoint generator (3). Finally, the accelerator pedal (1) is mechanically operatively connected to an idle switch (4) which, as shown in FIG. 1, is open when the accelerator pedal (1) is in the idle position shown. As soon as the accelerator pedal (1) is operated from the idle position, the idle switch (4) is closed. The first electrical setpoint generator (2), the second electrical setpoint generator (3) and the idle switch (4) are electrically conductively connected to an electrical control device (14) which is connected via further inputs (17), e.g. B. for the purpose of traction control, receives further input signals. The electrical control unit (14) is connected to a further motor control unit (15) for control, e.g. B. the ignition or gasoline injection, the internal combustion engine to which the first control unit (14), for. B. the currently measured throttle valve position for control purposes, whereas the second control unit (15) to the first control unit (14), z. B. a control signal for switching on the idle speed and the idle charge control. A malfunction of parts of the device according to the invention or of the entire device according to the invention can be indicated to the operator of the motor vehicle via an error indicator lamp (16). This error can be via an output (18) for diagnostic purposes, e.g. B. in a motor vehicle workshop, for the purpose of correcting the error.

The electrical control unit (14) generates an output signal depending on the input signal mentioned, which is fed to an electrical actuator (7) which, for. B. can be designed as an actuator. This electrical actuator (7) is mechanically operatively connected to a throttle valve (5) which is rotatably arranged in a throttle valve connector (6). The throttle valve (5) is on the other hand mechanically operatively connected to a first electrical actual value transmitter (8) and a second electrical actual value transmitter (9), the electrical signals of which are also fed to the electrical control unit (14) for the purpose of position control of the throttle valve (5).

The throttle valve (5) is spring-loaded by a return spring (10) in the direction opposite the normal open position of the throttle valve (5). If the servomotor (7) is in its de-energized state, the throttle valve (5) is connected by the force of the return spring (10) with a stop element (11), which can be designed as a lever and is mechanically operatively connected to the throttle valve (5) , pressed against a stop (12) which has a stop spring (13).

1 shows the currentless state of the electrical actuator. The servomotor (7) can, for. B. be de-energized because either the internal combustion engine (not shown in FIG. 1) is switched off or because an error in the device according to FIG. 1 has been determined.

In FIG. 2, the same or equivalent device parts as in FIG. 1 are provided with the same reference numerals. In FIG. 2, the fully closed position of the throttle cap (5) is marked with 0 degrees, in which the stop element (11) does not rest on the stop (12). On the other hand, the fully open position of the throttle valve (5 ') is shown in FIG. 2, in which, due to the geometry selected in FIG. 2, the stop element (11') is located on the 0 degree line.

The two positions of the throttle valve (5, 5 ') shown in FIG. 2 define the normal function range or the normal range of rotation of the throttle valve by the throttle valve (5) moves against the force of the return spring (10) when the device according to the invention and its individual parts function properly. The stop element (11) does not come into contact with the stop (12) in this normal function range, so that the stop element (11), the stop (12) and the stop spring (13) are without any function in this normal function range.

In FIG. 3, the same or equivalent device parts as in FIGS. 1 and 2 are provided with the same reference numerals. In this Figure 3, the emergency running position (5 '') of the throttle valve is shown, in which the stop element (11 '') would come to rest on the stop (12). Furthermore, FIG. 3 shows an emergency function position of the throttle valve (5 '' ') in which the stop element (11' '') rests on the stop (12) and, due to the force exerted by the electrical actuator, the stop spring (13) compresses. When the stop element (11 '') is in normal contact with the stop (12) without the servomotor (7) being energized, the throttle valve (5 '') has an opening angle (W1) which is approximately 5 degrees and an increased one Idle speed of the internal combustion engine corresponds to about 1200 rpm. In the case in which the servomotor (7) is fully energized, the throttle valve (5 '' ') has a rotary position that the throttle valve encloses an angle of approximately 10 to 15 degrees to the fully closed position, which means an idle speed of the operating warning internal combustion engine of approximately Corresponds to 3500 to 4000 revolutions.

The function of the device according to the invention in the event of a malfunction, e.g. B. of the two setpoints (2, 3) is as follows:
First, when the malfunction is detected by the electrical control unit, the electrical actuator (7) is switched off. By switching off the electrical actuator (7) by the restoring force of the return spring (10), the throttle valve (5 '') is rotated so far against the direction of the opening that the stop element (11) abuts the stop (12). Since the restoring force of the restoring spring (10) is less than the oppositely directed force of the stop spring (13), the throttle valve (5 '') remains in the position shown in FIG. 3 as long as the servomotor (7) is not energized. As soon as the servomotor (7) is energized because z. B. the electrical control unit (14) the closing of the idle switch (4) and thus the actuation of the accelerator pedal (1) from the idle position, the energization takes place only in the direction of the normal closing direction of the throttle valve (5), so that by the force exerted by the electric actuator (7), the throttle valve is moved into the position (5 ''') shown in FIG. 3 against the force of the stop spring (13).

As soon as the driver releases the accelerator pedal (1), the accelerator pedal (1) is moved back into the idle position by the force of the accelerator pedal return spring (19), so that the idle switch (4) opens. Now the opening state of the idle switch (4) is detected by the control device (14), which leads to the electrical actuator (7) being de-energized, so that the throttle valve moves into the position (5 '') shown in FIG. 3, due to the force of the stop spring (13) is moved back. The processes described are repeated every time the accelerator pedal (1) is actuated by the driver, so that in this emergency function area there is no continuous adjustment of the throttle valve (5), but two discrete throttle valve positions are present, which on the one hand cause the internal combustion engine to die in the emergency running position prevent and on the other hand, in the emergency function position (5 ''') driving the motor vehicle, e.g. B. to the nearest workshop.

A similar emergency function can also be carried out if the idle switch and a setpoint generator (2, 3) are defective, but the second setpoint generator (2 or 3) is still functional. In this case, a continuous adjustment of the throttle valve angle would in principle still be possible depending on the electrical signal of the respective setpoint generator (2 or 3). In this case, however, the driver should be informed at least via the error indicator lamp (16) that the device according to the invention has a defect.

Claims (10)

1. A device for controlling the power-output of a combustion engine for motor vehicles comprising a drive pedal (1) which is mechanically connected to an electrical nominal value transmitter (2, 3), a throttle valve (5), which affects the power output of the combustion engine and which is rotatably arranged in a throttle valve socket (6) and which is loaded in opposition to the opening position by a return spring (10), an electrical control element (7) which is mechanically connected to the throttle valve (5), and with an electrical control apparatus (14) which is fed the electrical signals of the nominal value transmitter (2, 3) as input signals and which generates in dependence of the input signals an output signal which is fed to the electrical control element (7), characterized in that the throttle valve (5) is arranged in the throttle-valve socket (6) in such a manner that it can rotate beyond a fully shut position, that a stop element (11) is provided which is mechanically connected to the throttle valve (5), and that a stop (12) is provided by means of which the stop element (11) is abutted in such a manner that the throttle valve (5) is beyond a fully shut position and past a normal opening position in an emergency operation position (5'').
2. A device according to claim 1, characterized in that, with proper functioning of the nominal value transmitter (2, 3), the control element (7) controls in both rotary directions of the throttle valve (5) so that the throttle valve (5) moves in an area of normal functions against the force of the return spring (10).
3. A device according to claim 1, characterized in that the stop (12) comprises a stop spring (13), the springload of which is directed in opposition to the return spring (10) and the springload of which is greater than the springload of the return spring (10) during abutment of the stop element (11) against the stop (12).
4. A device according to claim 3, characterized in that, in the event of malfunction of one or more transmitters (2, 3, 8, 9), the control apparatus (14) directs the control element (7) into a rotary direction of the throttle valve (5) so that the throttle valve (5) moves against the force of the stop spring (13) whilst within an emergency operation range.
5. A device according to claim 1, characterized in that an idle switch (4) is provided which is mechanically connected to the drive pedal (1).
6. A device according to claim 1, characterized in that a second nominal value transmitter (3) is provided, which is mechanically connected to the drive pedal (1).
7. A device according to claim 1, characterized in that one or more actual value transmitters (8, 9) are provided, which are mechanically connected to the throttle valve (5).
8. A device according to claim 1, characterized in that the operation of the transmitter (2, 3, 4, 8, 9) can be monitored via the control apparatus (14) when the combustion engine is switched off.
9. A device according to claim 8, characterized in that the throttle valve (5) is rotatable by way of the control apparatus (14) into specified rotary positions for the purpose of monitoring the operation.
10. A device according to claim 1, characterized in that the control apparatus (14) is provided with an overload protection for the control element (7).

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