JPH08210167A - Method and equipment for controlling idling of driving unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently charge a battery by a power generator in an idling condition and in an operating condition near idling by deciding the value of a holding battery voltage to a value, in which the battery is correctly charged. SOLUTION: A battery voltage UB, measured by a measuring device 22, is compared with a predetermined value of a battery voltage stored in a memory device 40 by a comparison device 36. A difference between a target value and the actual value of battery voltage is supplied and integrated to an integral device 56 in low-speed rotating speed. An output line of the integral device 56 forms a measure of the charge shortage of a battery, a charge shortage value is converted into a target value for idling rotating speed via a characteristic curvature in a characteristic device 64 to be supplied to a target value forming device 64. In the target value forming device 64, a target rotating speed value is formed to supplied to a comparison device 68, and is compared with the actual rotating speed. A control deviation is transmitted to the control device 72 so as to control a regulation device 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for controlling idling of a drive unit.

[0002]

2. Description of the Prior Art A method of this kind and a device of this kind are known from DE-A 38 32 727. In this patent, the idling rotational speed of the drive unit during idling is controlled so that the battery voltage is controlled to a predetermined value. In this case, the voltage level at which the battery voltage is maintained is determined by the appropriate selection of the characteristic curve for the battery voltage of the idling speed to be adjusted. With this characteristic curve, the idling rotation speed is adjusted so that the battery voltage is controlled to a predetermined fixed target value. In this case, it is clear that the voltage level of the battery is a function of the measured tolerance of the battery voltage and of the fluctuations of the control voltage, for example due to summer and winter operation of the generator. Therefore, according to known processes, battery charging is not guaranteed in all operating conditions by the generator during idling.

[0003]

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a drive unit idling control means which eliminates the above drawbacks.

[0004]

The process according to the invention ensures a sufficient battery charging by the generator at idling and at operating conditions close to idling.
Further, it is preferred that the voltage level at which the battery is charged is independent of tolerances in battery voltage measurements and generator control voltage variations.

It is particularly preferred to adapt the target voltage with which the battery is charged to the voltage present in the operating range with high rotational speeds. This is because, in this case, the generator can maintain the target voltage of the battery and thus replenish the insufficient charging of the battery due to the respective electric load. In this operating state, battery charging is ensured even when all loads are used.

Other advantages will be apparent from the following description of the embodiments.

[0007]

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 a control unit 10 which, via an output line 12, regulates the idling, preferably a throttle valve 18 provided in an intake system 16 of an internal combustion engine. It is connected to 14. The input line 20 connects the control unit 10 with a measuring device 22 for measuring the battery voltage U _B. Another input line 24 connects the control unit 10 with a measuring device 26 for measuring the engine speed. In this case, the battery voltage is in principle evaluated by measuring the supply voltage of the control unit 10. As a result, unknown line losses and contact resistances are included in the battery voltage measurement, these effects being reduced or interrupted during the control of the battery voltage by the process according to the invention. Further, input lines 28 to 30 are provided, and the input line 2
Reference numerals 8 to 30 connect the control unit 10 with measuring devices 32 to 34, which measure other operating variables of the drive unit or vehicle, such as engine temperature, the state of the attached load. The input line 20 leads to the comparison device 36 in the control unit 10, and the comparison device 36 is further provided with a line 38 from the storage device 40. Switch 43 from line 20 to storage device 40
Line 42 enters through. The output line of the comparison device 36 leads to the switch 48, and the second line of the switch 48
Is coupled to line 52 exiting storage device 50. The output line of the switch 48 leads to the integrator 56, the output line 58 of the integrator 56 leads to the characteristic device 60, in which a table or characteristic curve is stored. The output line 62 of the characteristic device 60 leads to a target value forming device 64, and the input lines 28 to 30 enter into the target value forming device 64. Target value forming device 6
The output line 66 of No. 4 communicates with another comparison device 68, and the input line 24 enters the comparison device 68 as a second input line. The output line 70 of the comparison device 68 leads to the control device 72, and the output line of the control device 72 is line 12.
Indicated by.

Line 74 leads from line 24 to threshold device 76, and output line 78 of threshold device 76 leads to switch 80. A line 84 from the first storage device 82 enters the switch 80, and the second storage device 8
Line 88 has entered from 6. The output line 90 of the switch 80 serves to adjust the integration constant of the integrator 56. A line 92 leads from the line 78 to the switch 48 for operating the switch 48. A line 44 leads from the line 92 to the switch 43. Switch 4
3, 48 and 80 are switched depending on the engine speed. The engine speed is the threshold device 76.
The switches 43, 48 and 80 are in the positions shown by the solid lines when the rotational speed threshold value is lower than a predetermined value, and are in the positions shown by the broken lines when the rotational speed threshold value is exceeded. In this case, in a preferred embodiment, the idling control device operates especially when the engine is idling and when the engine is idling when the travel pedal is released.

Even at the low idling rotational speeds that are normally used at present, it is observed that the battery is discharged when many electric loads such as seat overheating, rear glass overheating and headlights are inserted. When the battery voltage is too low, the idling speed is increased so that the drop in battery voltage due to this discharge is avoided.

For this purpose, according to the preferred embodiment shown in FIG. 1, the battery voltage U measured by the measuring device 22 is measured.
_B is compared in a comparison device 36, preferably after filtering the signal, with a predetermined target value U _{BS oll} of the battery voltage stored in a storage device 40. The difference between the setpoint value and the actual value of the battery voltage is supplied to the integrator 56 via the closed switch 48 at low rotational speed and is integrated there. The output line of the integrator 56 also forms a measure for the battery depletion. This undercharge value is converted into a target value for the idling rotational speed via an experimentally determined characteristic curve or table in the characteristic device 60 and supplied to the target value forming device 64. The target value forming device 64 forms a target rotational speed value, which is a function of the battery voltage, and a target rotational speed value, which is a function of operating variables, according to a process known from the prior art and compares the value representing the rotational speed to be adjusted 68 with a comparison device 68. Supply to. In the comparison device 68, the target rotational speed is compared with the actual rotational speed and the control deviation is proportional via line 70,
Informed to the controller 72, which is preferably a controller having an integral and / or derivative part. The control device 72 controls the adjusting device 14 in a direction to bring the actual rotation speed closer to the target rotation speed.

In this case, the integrator 56 operates using the integration constant provided from the storage device 82.

When the engine speed exceeds a predetermined threshold value, the threshold device 76 produces a corresponding signal.
In the preferred embodiment, a rotational speed value of about 3000 rpm has been found to be the preferred value. The signals of the threshold device 76 allow the switches 80, 48 and 4 to
3 is switched. In this operating state, the integrator 56 performs an integration using the integration constant stored in the memory 86, which in the preferred embodiment is stored as a value greater than the value in the memory 82. For high engine speeds, the integrator 56 is supplied via the switch 48 with the value -A, preferably -1, from the storage device 50 via line 52 instead of the control deviation. This results in a negative control deviation in the integrator 56, ie a control deviation representing a battery voltage greater than the target value. As a result, the integrator 56 reduces its integration state or output signal, which reduces the target rotational speed, which is a function of battery voltage.

Furthermore, the measuring device 26 has a high rotation speed and
When the engine speed measured by the switch exceeds the threshold value provided in the threshold device 76, the switch 43
Is closed and the battery voltage is supplied to the storage device 40, eg a low pass filter. At high rotational speeds, the battery voltage U _B is always stored in the storage device. When the rotational speed falls below the threshold value, the switch 43 is opened, and the battery voltage existing at this time is stored and used as a target value for battery voltage control.

Unlike the prior art, instead of being provided with a fixed predetermined value as the target value for controlling the battery voltage, in the case of high rotational speed the existing battery voltage value is provided. Become. This rotational speed threshold is selected so that at that rotational speed the generator can supply its maximum current on demand. In this operating state, the battery is reliably charged by the generator even when all the loads are inserted. Furthermore, in this operating state, the supply voltage of the control unit, which is used as a measure for the battery voltage, is almost certainly kept at a predetermined value (for example 14 V) by the generator controller even when the battery is discharged. To be done. In the preferred embodiment, a rotational speed threshold of 3000 rpm has been found suitable. By adjusting the battery voltage target value, the voltage drop between the vehicle-specific battery and the control unit is eliminated, thus improving the control of the battery voltage at idle.

When the engine is operated at a high rotational speed, the generator is in a state of recharging the battery at this time, and therefore, it is not necessary to generate the idling state again to further increase the idling rotational speed. 56 is slowly controlled using a time constant stored in memory 86.

As a supplement to the above embodiment, since the battery recovery time is required after the engine is started, the control of the battery voltage is started only after the elapse of a predetermined waiting time. This waiting time is 20 to 30 seconds in the preferred embodiment.

In addition to the above embodiment, in order to measure the battery voltage target value, in another preferred embodiment, the battery voltage is scanned every predetermined cycle time when the engine is running at high engine speed. It may be designed and stored, and in this case preferably the last actual value is selected as the target battery voltage value. In another preferred embodiment, the previous battery voltage measurement or the average of the battery voltage measurements traced back a predetermined time may be used as the new target value.

A flow chart of the preferred embodiment of the process according to the invention is shown in FIG. 2 as a computer program. In the first step 100 after the start of the program section, it is determined whether the start phase of the internal combustion engine is being performed. This determination is performed as a function of a counter that starts when a predetermined start terminal rotation speed is exceeded, in which case the above function is started when the counter exceeds a predetermined count state. If the internal combustion engine is in the start phase, step 102 initializes the integrating device and the storage device to predetermined values, and the program section ends. When the above function is initiated, in step 104 the operating variable to be processed, for example the battery voltage U
_B , the engine speed N _ist as well as other operating variables whose idling speed setpoint is determined as a function thereof are read. Then, in a determination step 106, it is determined whether the engine rotation speed is above a predetermined limit value N ₀ . If the determination is positive, the engine can be driven at a higher rotational speed and the target value of the battery voltage can be reached. Therefore step 1
At 08, the integration constant I _LBZ of the integrator 56 is set to the value I ₁ , the control deviation ΔU _B is set to the value −A, preferably −1, and the measured battery voltage U _B is set as the target value U _BSoll. To be done. Then step 11
At 0, the battery charge shortage LBZ is equal to the integration constant I.
It is calculated by integrating the control deviation using _LBZ . When it is detected in step 106 that the engine is not operating at the high rotation speed, step 11
2 sets the integration constant I _LBZ to the value I ₂ . The control deviation ΔU _B is formed from the difference between the stored target value U _BSoll and the measured battery voltage U _B. Subsequently, in step 110, the charge shortage LBZ is calculated. In the following step 114, the setpoint idling speed value N _SollB, which is a function of the battery voltage, is determined by an auxiliary characteristic curve, which is preferably determined linearly, as a function of the charge deficit LBZ. Subsequently, in step 116, the target idling rotational speed N _Soll is determined from the characteristic curve, characteristic curve or table as a function of the battery voltage and other operating variables. In step 118 following step 116, the target idling rotational speed is controlled by operating the adjusting device 14, that is, the throttle valve 18, in the case where the idling operation condition exists. After that, the program section ends.

FIG. 3 shows the process according to the invention in a time diagram. In this case, in FIG. 3a, the signal representing the idling state of the internal combustion engine is shown. At time T ₀ , this signal changes from the idling state to the non-idling operating state, while at time T ₃ , the conversion from the non-idling state to the idling state is performed. FIG. 3b shows the engine speed (solid line) as well as the target speed N
It indicated for _SollB the (dashed) time, whereas the battery voltage in FIG. 3c (U _B, solid line) and the target battery voltage (U _BSoll, dashed line) pertaining time is shown.

It is assumed that the battery voltage is controlled to the value U _B1 until the time point T ₀ . This is the target rotation speed N _SollB
Is achieved by At time T ₀ , the idling state of the internal combustion engine is disconnected. The engine speed is shown in Figure 3b.
Rise as shown in. At time T ₁ , the rotation speed exceeds the limit rotation speed N ₀ . Between times T ₀ and T ₁ , it is assumed that the battery is charged due to increasing engine speed and the battery voltage also rises slightly. The target value _UBSoll of the battery voltage remains constant, because in this time range the adaptation process does not take place because the rotational speed is too low. On the other hand, the target idling speed N _SollB between times T ₀ and T ₁ is calculated as a function of the deviation between the target and the actual value of the battery voltage. Due to the increasing deviation between the target battery voltage and the actual battery voltage,
The target idling rotation speed decreases between the time points T ₀ and T ₁ . At time T ₁ when the engine speed exceeds the threshold value N ₀ , the process of adapting the battery voltage target value is started. The battery setpoint U _BSoll reaches the actual value of the battery voltage U _B2 before time T ₂ probably due to the filter constants that will be used. When the engine speed again falls below the limit value N ₀ at time T ₂ ,
The battery voltage value existing at time T ₂ is stored as the target value. Between times T ₁ and T ₂ , the battery voltage target value U _BSoll approaches the measured battery voltage value U _B ,
On the other hand, the charge shortage decreases, so the target rotation speed value N _SollB
Is further reduced. In this case, since there is no mutual deviation between the target value and the actual value of the battery voltage between the time points T ₂ and T ₃ , the target value N _SollB of the engine rotation speed is the time point T ₂
Remains the value of. At time T ₃ , the internal combustion engine again enters the idling state, so that the engine speed N _Ist is then controlled to the predetermined target value N _SollB .

[Brief description of drawings]

FIG. 1 is a diagram of a preferred embodiment of an idling operation control device for realizing the process according to the present invention.

FIG. 2 is a flowchart showing the implementation of the process according to the present invention as a computer program.

FIG. 3 is a time diagram of a typical course of rotation speed and battery voltage illustrating the process according to the invention.

[Explanation of symbols]

10 Control unit 12, 20, 24, 28, 30, 38, 42, 44, 4
6, 52, 58, 62, 66, 70, 74, 78, 8
4, 88, 90, 92 Line 14 Regulator 16 Intake device 18 Throttle valve 22, 26, 32, 34 Measuring device 36, 68 Comparison element 40, 50, 60, 82, 86 Storage device 43, 48, 80 Switch 56 Integral Device 60 Characteristic device 64 Target value forming device 72 Control device 76 Threshold device I _LBZ , I ₁ , I ₂ Integral constant LBZ Insufficient charge LL idling status signal N Engine speed N _Ist Actual engine speed N ₀ Limit engine rotational speed N _SollB target engine rotational speed U _B battery voltage U _BSoll target battery voltage .DELTA.U _B control deviation

Claims (6)

[Claims] 1. At least one electrically operable adjusting device for influencing the output of the drive unit, which is operated in a direction to adjust to a predetermined idling rotational speed, said adjusting of the idling rotational speed. , The at least one performed so that a predetermined value of the battery voltage is held
In the method for controlling the idling of the drive unit using the two adjusting devices, the value of the battery voltage to be held is determined to be the value that exists in the operating state and that ensures that the battery is charged. A characteristic method of controlling the idling of the drive unit. 2. The method of claim 1, wherein the value of the battery voltage to be held is a value that is present at high engine speeds. 3. The control method according to claim 1, wherein the value of the battery voltage to be held is obtained from the measured value of the battery voltage when the engine rotation speed exceeds a predetermined limit rotation speed. . 4. The target idling rotational speed is calculated by comparing the measured value of the battery voltage with a target value and integrating the deviation between the target value and the actual value of the battery voltage.
4. The control method according to claim 1, wherein the target idling rotation speed is adjusted within a range of idling rotation speed control. 5. The control method according to claim 1, wherein the battery voltage is not controlled to a predetermined value during the start phase of the engine. 6. At least one electrically operable adjusting device for influencing the output of the drive unit, which is operated in a direction to adjust to a predetermined idling rotational speed, said adjusting of the idling rotational speed. , The at least one performed so that a predetermined value of the battery voltage is held
In a control device for idling of an internal combustion engine, which is equipped with two adjusting devices, the value of the battery voltage to be held is determined to be the value that exists in the operating state and that ensures that the battery is charged. A control device for idling of a characteristic internal combustion engine.