JPH08312406A - Method and equipment for controlling torque of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve compensation of torque change when inputting and/or cutting off a load by adjusting the air supply quantity and ignition timing in a direction of worsening the efficiency of an internal combustion engine prior to the change of the load. SOLUTION: A control unit 10 controls an electrically operable setting element 14 through an output line 12 so as to adjust the air supply quantity to an internal combustion engine. The control unit 10 is provided with at least one load 18 that can be inputted through another output line 16. The other output line 20 controls ignition timing of individual cylinders of the internal combustion engine. In this constitution, the air supply quantity and ignition timing of the internal combustion engine are adjusted prior to input or cut-off of additional load for applying the load 18 to the internal combustion engine. There is therefore hardly any sudden change of torque when inputting and/or cutting off the load 18, thereby generating no change of rotating speed nor sudden movement of the vehicle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque control method and device for an internal combustion engine.

A method of this kind or an arrangement of this kind is known from DE 34 39 927 (US Pat. No. 4,592,232).
No. 0). As an example of idling air supply control, there has been proposed a means for compensating for a sudden change in rotation speed or torque when a load such as an air conditioner, a transmission, a fan or a clutch is applied. This means consists of a pre-control of the idling air supply controller, in which the air supply to the internal combustion engine is increased when the load is turned on, independently of the controller. At this time, the increase coefficient of the air supply amount is adapted based on the output signal of the controller in the uncontrolled state. According to this principle, when the air supply amount is changed when the load is turned on or off, the influence of the change of the air supply amount on the torque or the rotational speed of the internal combustion engine occurs with a time delay, so that a known method or The known device shows unsatisfactory results in some applications, especially in low power engines. In this application example, the turning on or off of the load causes a relatively large change or fluctuation in the torque or the rotational speed, and this change or fluctuation may affect the riding comfort and maneuverability.

[0003]

It is therefore the object of the present invention to provide a means by which the compensation of torque changes is improved when switching on and / or off of the load.

[0004]

SUMMARY OF THE INVENTION A torque control method and apparatus for an internal combustion engine according to the present invention adjusts an air supply amount and an ignition timing of the internal combustion engine before turning on or off an additional load for applying a load to the internal combustion engine. . After the end of this phase the load is switched and the ignition timing is restored.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 shows an overall block circuit diagram of engine control. This includes idling speed control with pre-control and electric control of ignition timing as essential elements in view of the method according to the invention. Furthermore, the engine control switches at least one load in response to the corresponding demand signal. For the sake of clarity, in FIG. 1 only the essential elements associated with the method according to the invention when applying the load are shown.

FIG. 1 shows a control unit 10, which controls an electrically operable setting element 14 via an output line 12 to regulate the air supply to the internal combustion engine. In this case, the setting element 14 means an electrically actuable throttle valve, an electrically controllable bypass valve or an electrically controllable throttle valve stop for adjusting the idling setting of the throttle valve. Other output line 1
Via 6 the control unit 10 controls at least one loadable load 18, for example an air conditioner compressor, an automatic transmission, an electrically controllable clutch and / or an electrically controllable engine fan. . The other output line 20 controls the ignition timing of the individual cylinders of the internal combustion engine. An input line 24 leads from the measuring device 22 for measuring the engine speed to the control unit 10. further,
An input line 26 leads to the control unit 10 from at least one element 28 which forms a demand signal for switching at least one load. Another input line 30 leads to the control unit 10 from a measuring device 32 for measuring the engine load, for example an air quantity sensor or an intake pipe pressure sensor.

Depending on the type of load 18 that can be turned on, each at least one element 28 sends a switching signal for turning on the air conditioner (compressor of the air conditioner) in response to an operating switch or an operating pressure signal. A switching signal for closing the electric clutch in response to a driver's request for switching or a selected operating condition, an automatic transmission in response to a driver's corresponding switching request or selected operating condition (for example, from a parking position to a neutral position, A switching signal for switching on the engine fan is generated in response to a switching signal for controlling the neutral position to the driving position, etc. and / or in response to a corresponding closing signal and / or in some cases operating conditions such as engine temperature.

An idling rotational speed controller 34 is provided in the control unit 10, and the idling rotational speed controller 34 is supplied with a line 24 and a line 36 from a target value generator 38. The target value generator 38, in a preferred embodiment, has input lines 40 to 42 from a measuring device, not shown, for measuring operating variables of the internal combustion engine and / or the vehicle, such as engine temperature, running speed, etc.
Is supplied. The output line 44 of the idling speed controller 34 leads to a correction stage 46, the output line of the correction stage 46 representing the line 12. Furthermore, the first characteristic curve or the first characteristic curve group 48 is also part of the control unit 10. Line 2 is attached to these characteristic curves or characteristic curve group 48.
6 and selected lines 40-42 are provided. The output line 50 leads to the correction stage 46. In addition, a calculation block 52, preferably a time element, is provided, the calculation block 52 being fed by line 26 to line 51. The output line 16 is connected to the load 18 from the calculation block 52.
It leads to. Other characteristic curve group 54 for determining ignition timing
Is supplied with a line 56 and a line 30 which are output from the line 24. The output line 58 of the characteristic curve group 54 leads to the correction stage 60, and the output line of the correction stage 60 is line 2.
0. The correction stage 60 is supplied with input lines 62 and 63. An output line 62 is output from the controller 66, and the controller 66 is supplied with a line 68 from the line 24 and a line 70 from the line 36. Further in the preferred embodiment, a line 78 is provided from the output line 62 of the controller 66 to the characteristic curve group 48. An input line 63 is supplied from a pre-control block 65 for adjusting the ignition timing, which in the preferred embodiment is line 67.
And line 69 is fed from line 16.
The pre-control block 65 includes a table or a group of characteristic curves or a characteristic curve in which the change of the ignition timing is determined in response to a demand signal and a switching signal during the application of a load. .

During operation of the internal combustion engine, a target value forming unit 38 forms a target value of the idling rotational speed according to the supplied operating variable. Idling speed controller 3
4, the target value of the idling speed is compared with the measured engine speed and an output signal for adjusting the air supply to the internal combustion engine is generated according to a predetermined control strategy, eg PID, which output signal is the actual speed target. Move closer to the rotation speed. A group of characteristic curves 48, a so-called pre-control, is provided in order to improve the control action. The pre-control contains a variable characteristic curve which, for each operating variable supplied, contains a variable value of the air supply, i.e. a correction value of the output signal of the regulator.

Considering the loads that can be applied, such as air conditioners, automatic transmissions, electrically controllable clutches and / or fans, the amount of air supply depending on the presence of a request signal to apply these additional loads. A corresponding signal that increases is output from the characteristic curve group 48. This corresponding signal regulates the air supply via the correction stage 46, in which case a change in the air supply will linearly compensate for the additional torque required by the applied load. The ignition timing is controlled in a known manner on the basis of a preprogrammed characteristic curve group 54 as a function of the actual operating conditions.
The actual operating conditions are indicated by the measured engine speed and engine load, eg air flow or intake pipe pressure. In this case, the pre-programmed characteristic curves adjust the ignition angle in consideration of the optimization of the fuel consumption of the internal combustion engine. Therefore, in principle, the internal combustion engine is operated at least in the vicinity of this optimum ignition timing, and at this ignition timing, the internal combustion engine produces maximum torque with minimum fuel consumption. Internal combustion engines will also operate with high efficiency.

The torque generated by the internal combustion engine is substantially constant during the transition of the application of load or the interruption of the load, and in the transition state of the internal combustion engine, the load applied to the internal combustion engine or the load applied to the interruption of the load. Is preferably operated so as to compensate for This is achieved by the method of the invention. In this case, the operating point of the internal combustion engine is changed in a direction that deteriorates the efficiency in response to the request signal before the original load application or according to the interruption signal before the original load shedding, and at this time the load is not applied. Torque compensation is carried out when switching off and during or after the transition state,
The basic idea is to adjust the operating point of the internal combustion engine to improve efficiency again.

Specifically, when the demand signal is generated (line 26) and the load is turned on, the increase in air (characteristic curve group 48, correction stage 46) at a constant torque returns the ignition timing accordingly. In some cases (in the preferred embodiment, by returning via the pre-control block 65, the controller 6 is arranged to balance the resulting rotational speed deviation / torque deviation.
(Supported by 6), the load is switched (line 16) after the end of this process (time condition in block 52) and the required increase in engine torque causes the ignition timing to again reach its initial value range ( In the preferred embodiment, by returning via the pre-control block 65, supported by controller 66 to balance the resulting rotational speed / torque deviations.

Similarly, when the cutoff signal is generated (or the demand signal is removed) to cut off the load, the additional air is first adjusted so that the torque or rotation speed becomes constant when the ignition timing is returned correspondingly. The control is performed from the smaller one, so that the ignition timing is adjusted in the direction of increasing the torque. After the end of this process, the load is cut off, the air supply is reduced and the rotational speed deviation or torque increase occurring during the transition is adjusted via the ignition timing. After that, the original operating condition is set again by adjusting the air amount and then controlling the ignition timing to the value of the characteristic curve group 54.

The magnitude of the increase in the air supply is, in a preferred embodiment, based on a predetermined table, characteristic curve and / or characteristic curve group according to the signaling of the request signal and / or the signal magnitude (eg level). Will be decided.
In the preferred embodiment, before the load is applied, an adaptive correction of the additional amount of air supply is made as a function of the degree of engagement of the control via ignition timing during the transition state. The deviation between these modified output signals after the end of the load application, in particular the adjusted ignition timing and the optimum value of the characteristic curve group 54, indicates the value for the deviation of the preload control value from the ideal value. At this ideal value, the torque variation is adjusted linearly under the control of the ignition timing of the characteristic curve group after the transition state has ended. The effect of the ignition timing modification is also measured within the adaptive modification and the air pre-control value is adapted accordingly.

The ignition timing controller 66 performs rotation speed control, torque control or load control (air amount control, air capacity control, pressure control) according to the respective designs.

The restoration or resetting of the ignition timing, which is performed in response to the request signal or the switching signal, can be performed by various methods. In the preferred embodiment, in both cases, the ignition timing is varied according to a predetermined time function which may be the same or different. In another advantageous embodiment, a step change of ignition timing or a combination of time gradients and steps is used. Furthermore, it is also advantageous to adjust the ignition timing only via the controller 66, i.e. omitting the pre-control block 65.

In a particularly advantageous and simple embodiment, the closed-loop control of the ignition timing is not carried out, but instead only the open-loop control of the ignition timing is carried out, in which case the ignition timing is dependent on the air quantity. Is increased by a request signal in parallel with the increase of the load and is returned to its optimum value when the load is switched.

Furthermore, the method according to the invention exhibits the abovementioned advantages not only at idling but also at idling. Here, the ignition timing is reduced in response to the load input request signal, and the torque reduced thereby is balanced by adjusting the air supply amount through an idling setter or an electrically controllable throttle valve, at which time the load is reduced. Are switched and the ignition timing is restored. As a result, for example, cyclical switching of the compressor of the air conditioner is effectively compensated for even while the vehicle is running, and adverse effects on riding comfort are prevented. The same applies when the load is cut off.

2 and 3 show preferred embodiments of the method according to the invention when applying a load.

FIG. 2 is a time diagram of the request signal and the switching signal for the load when the load is turned on (FIG. 2).
a), a time diagram of the air supply amount to the internal combustion engine (Fig. 2b),
FIG. 2 shows a time diagram of the ignition timing (FIG. 2c) and a time diagram of the torque generated by the internal combustion engine (FIG. 2d).

At time T0, the engine control receives a request signal for turning on the load. This request signal adjusts the ignition timing so as to increase the amount of air supplied to the internal combustion engine to a predetermined value after time T0 and at the same time reduce the torque. In this case, this first phase of the method according to the invention is carried out in such a way that the effect of increasing the load and the effect of reducing the ignition timing exactly compensate for the torque of the internal combustion engine. Therefore, the torque generated by the internal combustion engine is kept substantially constant.
In this case, the ignition timing is adjusted starting from the ignition timing at which the fuel consumption amount set before time T0 is optimum, and the torque is kept constant through the rotation speed control, the load control or the torque control. Will be modified. After the increase of the air supply amount ends at time T1, the load is switched after a predetermined time has elapsed from the generation of the request signal and / or after the end of the increase of air (the air control signal remains substantially constant). The torque required to be generated by the engine at this time is increased to a value at which the fuel consumption of the engine is optimized by adjusting the ignition timing after time T1, and at this time, in the ideal case, the change of the air supply amount is changed. Is not necessary. By correcting the ignition timing adjustment within the range of the rotational speed control, the load control or the torque control, the torque generated by the internal combustion engine is controlled to be substantially constant even when the load is actually applied.

In the preferred embodiment, the increase in the air supply at time T0 is made such that at time T1 the ignition timing adjustment to be completed is just equal to the torque required to operate the additional load. Be seen.
Since this predetermined allocation may change during driving of the motor vehicle, an adaptive correction of this increase value is made in the preferred embodiment. Since the adjustment of the ignition timing controller after the completion of the transition shows the deviation from the ideal value of the torque adjusted by the air supply amount at the optimum ignition timing, the adjusted ignition timing is adjusted according to the deviation from the optimum ignition timing. The increase in air is corrected so that the ignition timing corresponds to the optimum ignition timing. After the end of the load increase process, when the optimum ignition timing is adjusted, an adaptive correction of the air increase value is also carried out, as is known from the prior art and optionally by means of the idling speed controller.

FIG. 3 shows a flow chart providing guidance for carrying out the method according to the invention described above. The program part shown in FIG. 3 starts with the generation of a request signal. In the first step 100, the air supply amount is increased and the ignition timing Zzp is decreased by the pre-control in accordance with a predetermined increase value stepwise according to the request signal or based on a predetermined time function. In the subsequent step 102, a difference between the target rotational speed N _soll and the actual rotational speed N _ist is formed, and the ignition timing correction Zz is adjusted depending on the difference.
pkorr is performed. In this case, in steps 100 and 102, the air supply amount and the ignition timing are adjusted so as to keep the torque constant after the time point T0. In step 104, it is determined whether the increase in air has ended. This is detected, for example, by changes in the air supplied to the internal combustion engine and / or based on time conditions. When the increase of the air is not finished, step 100 is repeated if the air supply amount and / or the ignition timing is adjusted according to a time function, and if the air supply amount and the ignition timing are adjusted stepwise. 102
Is repeated. When the air growth is complete, step 106 outputs a switch signal and the load is turned on. In the subsequent step 108, the ignition timing Zz
p is returned to the characteristic curve group value Zzpopt according to a predetermined time function or stepwise, in this case step 11
When the engine rotational speed is controlled to 0, the target rotational speed is corrected to ZW _korr , whereby the torque to be generated is held constant. In the following step 112, it is queried whether the load increase process has ended. This is done either by time conditions or by determining whether the ignition timing is substantially stationary. If this is not the case, step 108 is repeated when adjusting the ignition timing according to a time function and step 1 when adjusting it stepwise.
10 is repeated. At the end of the augmentation process, in an advantageous embodiment, according to step 114, the deviation of the adjusted ignition timing from the optimal fuel consumption ignition timing, indicated by the controller correction value Zzzpkorr, results in an increase in the air supply. It is used to correct the value and the air supply is adjusted to obtain the optimum ignition timing. Then the program part ends.

[0025]

The method according to the invention improves the riding comfort and the drivability of the internal combustion engine when the load is switched on and / or off. In this case, the time course of the torque applied by the internal combustion engine is kept substantially constant when the load is switched on and / or off by the method according to the invention, so that there is almost no sudden change in torque, which also causes a change in rotational speed. It is particularly advantageous that no sudden movements of the can occur.

It is particularly advantageous that the load change is compensated very quickly by adjusting the ignition angle, and that the delay due to system conditions is not a problem when adjusting the torque via the air supply.

Despite the adjustment of the ignition angle when the load is turned on and / or off, the internal combustion engine has an ignition angle which is optimal or at least close to fuel consumption, and therefore highly efficient, except in transitional operating conditions. It is further advantageous to be able to operate in the range. The advantage of the method according to the invention is obtained, since the improvement of the riding comfort does not entail wasted consumption of fuel.

The method according to the invention is of particular significance when loading the load and is therefore advantageous if used only during the loading process. Furthermore, the method according to the invention can be used to improve the ride comfort with a relatively small impact when the load is turned on, or when the load is cut off, for example to reduce the air flow, such as to reduce the torque. Can be used in combination with other methods such as adjusting the ignition angle so as to reduce the torque in parallel with the adjustment of the.

[Brief description of drawings]

FIG. 1 is an overall block circuit diagram of an internal combustion engine controller showing a method according to the present invention in a preferred embodiment.

FIG. 2 is a time diagram of the method according to the invention when a load is applied.

FIG. 3 is a flow chart of the method according to the invention when a load is applied.

[Explanation of symbols]

10 control units 12, 16, 20, 24, 26, 30, 36, 40, 4
2, 44, 50, 51, 56, 58, 62, 63, 6
7, 68, 69, 70, 78 Line 14 Setting element 18 Load 22 Engine rotation speed measuring device 28 Load turning on / off request signal forming element 32 Engine load measuring device 34 Idling rotation speed controller 38 Target value forming device 46, 60 Modified Steps 48, 54 Characteristic curve (or characteristic curve group) 52 Calculation block 65 Previous control block 66 Controller M Torque N _ist Actual rotation speed value N _soll Target rotation speed value QL Air supply amount ZW, Zzzp Ignition timing Zzzpkroo Correction of ignition timing Value Zzpopt Value of characteristic curve of ignition timing

Claims (10)

[Claims] 1. A control unit for adjusting at least an air supply amount to an internal combustion engine and an ignition timing of the internal combustion engine,
In a torque control method for an internal combustion engine, which comprises at least one load for applying a load to the internal combustion engine in response to at least one request signal, the amount of air supply and the ignition timing first improve the efficiency of the internal combustion engine before a load change. A torque control method for an internal combustion engine, characterized in that the torque is adjusted in a worsening direction. 2. The method according to claim 1, wherein the adjustment of the air supply amount and the ignition timing is performed so that the torque provided by the internal combustion engine is kept substantially constant. 3. The air supply amount to the internal combustion engine is adjusted to be momentarily increased, while the ignition timing is adjusted to be momentarily reduced. the method of. 4. A method as claimed in claim 1, characterized in that the air supply is increased so that the required torque change remains linear due to load changes. 5. The method according to claim 1, wherein the ignition timing is adjusted to its initial value as the load changes. 6. The method according to claim 1, wherein the torque deviation or the rotational speed deviation is compensated by modifying the ignition timing within the rotational speed control, the load control or the torque control. 7. The value for changing the air supply amount is corrected after a load change based on the deviation of the adjusted ignition timing from the ignition timing to be set.
To any one of 6 to 6. 8. The method according to claim 1, wherein the ignition timing is adjusted to or near a consumption optimum value outside the operating state of load change, whereby the internal combustion engine operates with high efficiency. Either way. 9. The load change is performed when a load that can be applied, such as an air conditioner, an automatic transmission, an electric control clutch and / or an electric engine fan, is turned on or off. The method according to any one of claims 1 to 8. 10. A control unit for adjusting at least an air supply amount to an internal combustion engine and an ignition timing of the internal combustion engine, and at least one load for applying a load to the internal combustion engine in response to at least one request signal. In a torque control device for an internal combustion engine, the control unit first adjusts an air supply amount and an ignition timing in a direction in which efficiency of the internal combustion engine is deteriorated before a load change.