JP4156043B2 - Method and apparatus for controlling idling of drive unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for controlling idling of a drive unit.
[0002]
[Prior art]
A method of this kind or a device of this kind is known from German Offenlegungsschrift 3,832,727. In this patent, in idling, the idling rotational speed of the drive unit is controlled such 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 appropriate selection of a characteristic curve relating to the battery voltage of the idling rotation 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 measurement tolerance of the battery voltage and a function of the variation of the control voltage, for example due to summer and winter operation of the generator. Thus, in some known processes, battery charging is not guaranteed in all operating conditions by the generator during idling.
[0003]
[Problems to be solved by the invention]
Accordingly, it is an object of the present invention to provide a drive unit idling control means that eliminates the above-mentioned drawbacks.
[0004]
[Means for Solving the Problems]
The process according to the invention ensures sufficient battery charging by the generator at idling and in operating conditions close to idling. Furthermore, the voltage level at which the battery is charged is preferably independent of tolerances in battery voltage measurements and variations in generator control voltage.
[0005]
It is particularly preferred to match the target voltage at which the battery is charged to the voltage present in the operating range with a high rotational speed. This is because, in this case, the generator holds the target voltage of the battery, and therefore can replenish the insufficient charge of the battery due to the respective electrical load. In this operating state, the battery is reliably charged even when all loads are used.
[0006]
Other advantages are apparent from the description of the examples below.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below with reference to embodiments shown in the drawings.
[0008]
A control unit 10 is shown in FIG. 1, which is connected via an output line 12 to an adjusting device 14 for adjusting idling, preferably for adjusting a throttle valve 18 provided in the intake device 16 of the internal combustion engine. Has been. Input line 20 has a control unit 10 connected to the measuring device 22 for measuring the battery voltage U _B. Another input line 24 connects the control unit 10 to a measuring device 26 that measures the engine speed. In this case, the battery voltage is in principle evaluated by measuring the supply voltage of the control unit 10. This includes unknown typical line loss and contact resistance in the battery voltage measurement, and these effects are reduced or cut off during battery voltage control by the process according to the invention. Further, input lines 28 to 30 are provided, and the input lines 28 to 30 connect the control unit 10 to the measuring devices 32 to 34. The measuring devices 32 to 34 are a driving unit for the engine temperature, the state of the attached load, etc. Measure the operating variables. The input line 20 communicates with the comparison device 36 in the control unit 10, and the comparison device 36 further receives a line 38 from the storage device 40. A line 42 enters the storage device 40 via the switch 43 from the line 20. The output line of the comparator 36 leads to the switch 48, and the second input of the switch 48 is coupled to the line 52 exiting from the storage device 50. The output line of the switch 48 communicates with the integrating device 56, and the output line 58 of the integrating device 56 communicates with the characteristic device 60, and a table or characteristic curve is stored in the characteristic device 60. 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 the target value forming device 64. The output line 66 of the target value forming device 64 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 indicated by line 12.
[0009]
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 enters the switch 80 from the first storage device 82 and a line 88 enters the second storage device 86. The output line 90 of the switch 80 serves to adjust the integration constant of the integrator 56. Line 92 leads from switch 78 to switch 48 to operate switch 48. A line 44 leads from the line 92 to the switch 43. Switches 43, 48 and 80 are switched depending on the engine speed. When the engine speed falls below the speed threshold given in advance in the threshold device 76, the switches 43, 48 and 80 are in the positions indicated by the solid lines, and exceed the speed threshold. In the position indicated by the broken line. In this case, in a preferred embodiment, the idling control device operates especially when the engine is idling and when it is close to idling when the travel pedal is released.
[0010]
Even at low idling rotational speeds that are normally performed at present, there is a phenomenon that the battery is discharged when many electric loads such as sheet overheating, rear glass overheating, and headlights are inserted. The idling rotation speed is increased when the battery voltage is too low so as to avoid a decrease in the battery voltage due to the discharge.
[0011]
For this, the preferred embodiment shown in FIG. 1, the battery voltage U _B that is measured by the measuring device 22, preferably in the comparator 36 after filtering a signal, the battery voltage stored in the storage device 40 It is compared with a predetermined target value U _BSoll . The difference between the target value and the actual value of the battery voltage is supplied to the integrating device 56 via the switch 48 which is closed at low rotational speed and integrated there. The output line of the integrator 56 also forms a measure for battery undercharge. 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 that is a function of the battery voltage and a target rotational speed value that is a function of the operating variable according to a process known from the prior art and compares the value representing the rotational speed to be adjusted with the comparing device 68. To supply. In the comparison device 68, the target rotational speed is compared with the actual rotational speed and the control deviation is transmitted via the line 70 to the control device 72, which is preferably a controller having a proportional, integral and / or differential part. The control device 72 controls the adjusting device 14 in a direction in which the actual rotational speed is brought close to the target rotational speed.
[0012]
In this case, the integrating device 56 operates using the integration constant given from the storage device 82.
[0013]
When the engine speed exceeds a predetermined threshold, the threshold device 76 generates a corresponding signal. In a preferred embodiment, a rotational speed value of about 3000 rpm has been found to be a preferred value. The switches 80, 48 and 43 are switched by a signal from the threshold device 76. The integrator 56 performs integration using the integration constant stored in the storage device 86 in this operating state, and this integration constant is stored as a value greater than the value in the storage device 82 in the preferred embodiment. In the case of a high engine speed, the value -A, preferably -1, is supplied from the storage device 50 via the line 52 to the integrating device 56 via the switch 48 instead of the control deviation. For this reason, the integrating device 56 has a negative control deviation, that is, a control deviation representing a battery voltage larger 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 the battery voltage.
[0014]
Further, when the engine speed measured at the high speed and the measuring device 26 exceeds a threshold value provided in the threshold device 76, the switch 43 is closed and the battery voltage is stored in the storage device 40, for example. Supplied to the low-pass filter. For high rotational speed, always the battery voltage U _B is stored in the storage device. When the rotation speed threshold value is exceeded, the switch 43 is opened, and the battery voltage present at this time is stored and used as the target value for battery voltage control.
[0015]
Unlike the prior art, a predetermined value fixed as a target value for control of the battery voltage is not given, but an existing battery voltage value is given in the case of a high rotational speed. This rotational speed threshold is selected so that the generator can supply its maximum current according to demand at that rotational speed. In this operating state, the battery is reliably charged by the generator even when all loads are inserted. Furthermore, in this operating state, the supply voltage of the control unit used as a measure for the battery voltage is almost certainly maintained at a predetermined value (for example 14V) by the generator controller even when the battery is discharged. Is done. In a preferred embodiment, a rotation speed threshold of 3000 rpm has been found to be appropriate. By adjusting the battery voltage target value, the voltage drop between the battery and the control unit inherent in the vehicle is eliminated, thus improving the control of the battery voltage at idling.
[0016]
When the engine is operated at a high rotational speed, the generator is now in a state of recharging the battery, so that it is not necessary to generate an idling state again to further increase the idling rotational speed, so that the integrator 56 stores It is slowly controlled using the time constant stored in device 86.
[0017]
In addition 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 a predetermined standby time has elapsed. This waiting time is 20 to 30 seconds in the preferred embodiment.
[0018]
In addition to the above embodiment, in order to measure the battery voltage target value, in another preferred embodiment, the battery voltage is scanned and stored at predetermined cycle times when the engine is operating at high engine speed. In this case, however, the last actual value may be selected as the battery voltage target value. In other preferred embodiments, the previous battery voltage measurement or the average of the battery voltage measurements backed by a predetermined time may be used as the new target value.
[0019]
FIG. 2 shows a flowchart of a preferred embodiment of the process according to the invention as a computer program. In a first step 100 after the start of the program part, 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 end rotational speed is exceeded. In this case, the above function is started when the counter exceeds a predetermined count state. When the internal combustion engine is in the start phase, the integrator and the storage device are initialized with predetermined values in step 102, and the program unit is terminated. When the above function is started, in step 104, operating variables to be processed, for example, battery voltage U _B , engine speed N _ist, and other operating variables whose idling speed target value is determined as a function thereof are read. It is. Subsequently, in determination step 106, whether the engine rotational speed is present above a predetermined limit value N ₀ is determined. If the determination is affirmative, the engine can be driven at a higher rotational speed and reach the target value of the battery voltage. Accordingly, in step 108, 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 to the target value U _BSoll. Set as Subsequently, at step 110, the undercharge LBZ of the battery is calculated by integrating the control deviation using the integration constant I _LBZ . When it is detected in step 106 that the engine is not operating at a high rotational speed, the integral constant I _LBZ is set to the value I ₂ in step 112. A 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 idling rotational speed target value N _{SollB as} a function of the battery voltage is determined by means of an attached characteristic curve which is determined experimentally as a function of the _undercharge LBZ and is preferably linear. Subsequently, in step 116, the target idling speed N _Soll is determined from the characteristic curve, characteristic curve group or table as a function of the battery voltage as well as 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, when the idling operation state exists. Thereafter, the program section ends.
[0020]
FIG. 3 shows the process according to the invention in a time diagram. In this case, FIG. 3a shows a signal representing the idling state of the internal combustion engine. At time T ₀ , this signal changes from an idling state to a non-idling operating state, while at time T ₃ a conversion from a non-idling state to an idling state takes place. FIG. 3b shows the engine speed (solid line) and the target speed N _SollB (dashed line) with respect to time, while in FIG. 3c the battery voltage (U _B , solid line) and the target battery voltage (U _BSoll , dashed line) over time. It is shown.
[0021]
It is assumed that the battery voltage is controlled to the value U _B1 until time T ₀ . This is achieved by the target rotational speed N _SollB . At the time T ₀ , the idling state of the internal combustion engine is disconnected. The engine speed increases as shown in FIG. 3b. Rotational speed at the time point T ₁ is greater than the limit rotational speed N _0. Between time T ₀ and T ₁ , it is assumed that the battery is charged as the engine speed increases and the battery voltage also increases slightly. In this time range, the battery speed target value U _BSoll remains constant because the rotational speed is too low to perform the adaptation process. On the other hand, the target idling rotational speed N _SollB between the time points T ₀ and T ₁ is calculated according to the deviation between the target value and the actual value of the battery voltage. Since the deviation between the target battery voltage and the actual battery voltage increases, the target idling rotational speed decreases between the time points T ₀ and T ₁ . At the time T ₁ when the engine speed exceeds the threshold value N ₀ , the battery voltage target value adaptation process is started. Due to the filter constant that will probably be used, the battery target value U _BSoll reaches the actual value U _B2 of the battery voltage before time T ₂ . When the engine rotational speed falls below a limit value N ₀ again at time T _2, the battery voltage value present at the time T ₂ is stored as a target value. Between time points T ₁ and T ₂ , the battery voltage target value U _BSoll approaches the measured battery voltage value U _B , while the insufficient charging amount decreases, so that the target rotational speed value N _SollB is further reduced. In this case, since there is no 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 speed remains the value at the time point T _2. . At the time T ₃ , the internal combustion engine again enters the idling operation state, and therefore, at this time, the engine speed N _Ist is controlled to a predetermined target value N _SollB .
[Brief description of the drawings]
FIG. 1 is a diagram of a preferred embodiment of an idling operation control apparatus that implements a 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, 46, 52, 58, 62, 66, 70, 74, 78, 84, 88, 90, 92 Line 14 Control device 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 Integration device 60 Characteristic device 64 Target value forming device 72 Control device 76 Threshold Value device I _LBZ , I ₁ , I ₂ Integral constant LBZ Insufficient charge LL Idling state signal N Engine speed N _Ist Actual engine speed N ₀ Limit engine speed N _SollB Target engine speed U _B Battery voltage U _BSoll target battery voltage ΔU _B control deviation

Claims (4)

At least one adjusting device, which is operated to adjust to a predetermined idling rotational speed and influences the output of the drive unit,
In the method for controlling idling of the drive unit using the at least one adjusting device, wherein the adjustment of the idling rotational speed is performed so that a predetermined value of the battery voltage is maintained.
Measuring an actual battery voltage value at a high engine speed exceeding a predetermined threshold;
Storing the actual voltage value at the measured high-speed engine rotation speed as a target battery voltage value in an idling operation state of the engine;
Measuring an actual battery voltage value at an engine speed equal to or lower than the predetermined threshold;
Comparing an actual battery voltage value at an engine speed below the predetermined threshold with the target battery voltage value, and calculating a target idling speed from a control deviation between the two,
A method of controlling the idling of the drive unit, comprising the step of bringing the engine rotation speed in an idling operation state close to the target idling rotation speed to ensure sufficient battery charging.   The control method according to claim 1, wherein the target idling rotational speed is adjusted within a range of idling rotational speed control.   The control method according to claim 1, wherein the battery voltage is not controlled to a predetermined value during the engine start phase. At least one adjusting device, which is operated to adjust to a predetermined idling rotational speed and influences the output of the drive unit,
In a control device for idling of an internal combustion engine comprising said at least one adjusting device, wherein this adjustment of the idling rotational speed is performed such that a predetermined value of the battery voltage is maintained.
The adjusting device comprises:
A function for measuring the actual battery voltage value at a high engine speed exceeding a predetermined threshold and the actual voltage value at the measured high engine speed are stored as a target battery voltage value in an engine idling operation state. Function to
A function of measuring an actual battery voltage value at an engine speed equal to or lower than the predetermined threshold;
A function of comparing an actual battery voltage value at an engine speed below the predetermined threshold with the target battery voltage value and calculating a target idling speed from a control deviation between the two,
A drive unit idling control device that performs a function of guaranteeing sufficient battery charging by causing an engine rotation speed in an idling operation state to approach the target idling rotation speed.

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