GB2269919A

GB2269919A - Control of a throttle setting device in a vehicle

Info

Publication number: GB2269919A
Application number: GB9313193A
Authority: GB
Inventors: Eberhard Lang
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1992-07-02
Filing date: 1993-06-25
Publication date: 1994-02-23
Anticipated expiration: 2013-06-25
Also published as: GB9313193D0; JPH0658190A; DE4221674A1; GB2269919B

Description

2269919 CONTROL OF A SETTING DEVICE IN A VEHICLE The present invention

relates to a method and control means for control of a setting device in a vehicle.

So-called I'dashpot" controls are known in the field of the control of vehicle engines. Their basic manner of function consists in that, on rapid transition from travel operation with actuated accelerator pedal to idling operation with released accelerator pedal, the air quantity inducted by the engine reduces gradually, rather than suddenly, to the value required for the idling state. This measure leads to improvements in travel smoothness, since an underswing of engine speed can be avoided, as well as to improvements in the exhaust gas composition, since this composition can be regulated to the desired value even in this rapid transition in state.

Different arrangements are known for the realisation of these functions. For example, a device which for the setting of a throttle flap has an abutment movable by a setting motor, is described in DE-OS 37 20 255 (US-PS 5 046 467).

The idling speed is set in the idling state of the engine through adjustment of this abutment. For realisation of the dashpot function outlined above, in the case of a throttle flap actuated by the driver, the movable abutment - when the flap lifts off the abutment - is moved to a predetermined position which is usually situated above the positional range required for the idling regulation. When the driver releases the accelerator pedal, the throttle flap contacts the movable abutment in this higher position and the abutment is moved, according to a predetermined function, back into the position necessary for idling regulation. In effect, the throttle flap is caught while falling back and the improvements mentioned above in respect of travel smoothness and the exhaust gas compositions are achieved. Measures for the determination of the preset setting, the so-called dashpot angle, or measures for securing application of the dashpot function in as far as possible, all operating ranges, are not described in this prior art document.

There is therefore still a need for measures whereby the determination of this preset setting may be made possible and/or which may permit use of the dashpot function in, sofar as possible, all operating phases.

According to a first aspect of the present invention there is provided a method for the control of a setting device in a vehicle, in which an electrical drive signal for the setting device is formed in dependence on a target value for and an actual value of the setting of the device and a predetermined setting signal is produced in at least one first operational state of the vehicle or component thereof, wherein said setting signal in at least one predetermined operational situation has a substantially almost equal spacing from the setting of the setting device in at least one second operational state of the vehicle or the component.

According to a second aspect of the invention there is provided control weans for control of a setting device in a vehicle, ccffprising regulating means for formation of an electrical drive signal for the setting device in dependence on a target value for and an actual value of the setting of the device and for producing a predetermined setting signal in at least one first operational state of the vehicle or component thereof, wherein said setting signal in at least one preset operational situation has a substantially almost equal spacing from the setting of the setting device in at least one second operational state of the vehicle or the component.

It is known from DE-OS 35 37 913 (US-PS 4 672 935), in conjunction with a bypass valve for the regulation of engine idling speed, to determine the degree of openi.ng of the bypass valve when the throttle flap is actuated in dependence on operating parameter magnitudes such as engine temperature and throttle flap angle on the basis of an individual characteristic values field. This method does not lead to a substantially fixed spacing of the setter opening relative to that assumed in the idling state, since further influencing magnitudes, for example drift phenomena and so forth, are not taken into consideration. Moreover, increased effort is required for the determination of the characteristic value field or fields,in respect of which the actual operating conditions of the idling regulation cannot be taken into consideration.

Finally, it is known from US-PS 4 344 399 to adapt setting values of a setting device for idling regulation in dependence on engine load in the steady idling case. For this purpose, a difference between target engine speed and the actual engine speed is detected in the steady idling case when the setting value for the respective load has been issued. The setting value is then corrected in such a manner that the actual speed substantially corresponds to the target speed.

Outside the steady idling state, thi s corrected setting value determines the target value for the setting of the setting device in the sense of a desired idling speed.

A method exemplifying and control means embodying the invention may, by contrast, have the advantage of allowing the dashpot function to be activated over the entire engine operating cycle. Particular advantages result, in that case, during warming-up of the engine. Moreover, it can be possible to set the setting device in the sense of a dashpot function by way of a single. characteristic values field. In that case, operating parameter magnitudes, drift phenomena and other interference magnitudes can be taken into consideration in advantageous manner and their influence on the dashpot angle is eliminated. This leads to an exact setting of the angle, in particular in that the angle in every operating position may be able to be set in the sense of an optimal functioning of the dashpot function.

An example of the method and an embodiment of the control means of the invention will now be more particularly described with reference to the accompanying drawings, in which:

Fig. 1 is a schematic diagram of control means embodying the invention; and Fig. 2 is a flow chart illustrating steps in a method exemplifying the invention.

__5 - Referring now to the drawings there is shown in Fig. 1 a throttle flap 12' in the induction system 14 of an internal combustion engine (not illustrated), which throttle flap is connected by way of a mechanical connection with an operating device 18, in part icular an accelerator pedal, actuable by the driver of a vehicle fitted with the engine. The throttle flap is actuated by way of a movable abutment 52 for the setting of engine idling speed and the position of the abutment is controlled by a control unit 10. Measuring devices 20 to 22 are provided for operating parameter magnitudes of the vehicle and/or the engine and are connected with the control unit 10 by way of input lines 24 to 26. The input lines 24 to 26,as well as aline 44 which transmits a value indicative of the setting of the abutment 52 from a measuring device 46, are connected in the control unit 10 to a preliminary control element 28 for the formation of a target value for the setting of the throttle flap 12 and also with an adaptation element which takes drift phenomena into consideration and correspondingly corrects the target value ascertained by the preliminary control element 28. An output line 32 of the element 28 and an output line 34 of the element 30 are coupled together at an interlinking element 36 at which the afore-mentioned correction is realised. An output line 38 of the interlinking element 36 leads by way of a switching element to a regulating unit 42, to which the value indicative of the setting of the abutment 52 is fed by way of the line 44. An output line 48 of the regulating unit 42 leads to a drive element 50, which comprises output stages and a setting motor. The drive element 50 in that case actuates the abutment 52 for the setting of the throttle flap.

A line 56 leads from a junction 54 on the line 38 to a junction 58, from which a first line 60 leads by way of a switching element 62 to a further interlinking element 64, whilst a second line 66 leads to yet another interlinking element 68.

Also led to the interlinking element 64 is a line 80, which is connected with a measuring device 82, for example a potentiometer, for the setting of the throttle flap itself. An output line 70 of the interlinking element 64 leads to an element 72 for ascertaining the so-called dashpot angle. An output line 74 of the element 72 leads to the interlinking element 68, an output line 76 of which leads to a switch contact 78 of the switching element 40.

The manner of operation of.the system illustrated in Fig. 1 is as follows. The preliminary control element 28 ascertains a target value for the setting of the throttle flap 12, which target value leads to the maintenance of a desired preset rotational idling speed in the idling state, from the magnitudes fed by way of the lines 24 to 26.

Tge magnitudes are, in particular, engine temperature, travel speed, status of power-consuming devices such as air-conditioning system, steering assistance, etc, battery voltage, engine speed, selected gear setting and so forth. This target setting value is transmitted by way of the line 32, 38 and the switching element 40 as target setting value for the regulating unit 42. It is to be noted that the illustrated setting of the switching element 40 is the setting for the idling state of the engine. Outside the idling state, i.e. when the accelerator pedal is actuated and the vehicle is moving, the switching element 40 moves into the other setting so that the switch contact 78 is connected with the regulating unit 42.

7 During operation of the engine, the association in the preliminary control element 28 can be displaced through drift phenomena, for example aging, as well as through other interference magnitudes, for example height above sea level. These variations are taken into consideration by the adaptation element 30. This element forms, in a predetermined operational state, a correction value for the target value ascertained by the preliminary control element 28 in such a manner that the rotational speed of the engine is led to the desired target speed. The correction value is added in the interlinking element 36 to the target value of the preliminary control element 28 by way of the line 34. Consequently, drift influences as well as aging phenomena and other interfering influences can be take into consideration and eliminated.

In the idling state, the regulating unit 42, which can have integral, proportional and/or differential behaviour, compares this formed target value with the actual setting value of the abutment 52 fed by way of the line 44 and forms an output signal which, by way of the drive element 50, sets the throttle-flap in such a manner that the actual value is made to approach the target value. In an advantageous embodiment, the setting regulation of the throttle flap in the idling state is performed on the basis of the setting of the throttle flap detected by the measuring device 82.

The idling state is preferably ascertained when the throttle flap 12 bears agai nst the abutment 52. Alternatively, the idling state can be ascertained by reference to the released accelerator pedal.

8 Outside the idling state, the switching element 40 passes over into thd position not illustrated in Fig. 1 and connects the contact 78 with the regulating unit 42, the switch 62 closing at the same time. Consequently, the afore-described target value predetermination is uncoupled from the regulating unit 42 and replaced by target value preparation as described in the following. The target value, which is ascertained by the preliminary control element 28 and the adaptation element 30, is fed by way of the lines 56 and 60 to the interlinking element 64 so that it can be set into relation with the actual setting value of the throttle flap 12; in particular, the difference of these two values is formed. This difference is fed by way of the line 70 to the characteristic values field 72, which provides a relationship of the difference between the target and actual values to the setting of the so- called dashpot angle. A value of increase for the target value ascertained by the elements 28 and 30 is issued from the field 72 by way of the line 74 and interlinked additively with the afore-mentioned target value for the formation of a new target value in the interlinking element 68. This new target val'ue is fed by way of the line 76' and the now activated contact of the switching element 40 to the regulating unit 42, which sets the movable abutment 52 in correspondence with this new target value. The abutment is thus moved into the preset dashpot position and the initially mentioned advantages are achieved.

In particular, through formation of the value of increase by way of the 'field 72 in dependence on the target value ascertained by the preliminary control element 28 and the adaptation element 30, all operating parameter magnitude dependencies, in particular the temperature dependence important for warming-up behaviour, drift phenomena and other disturbing influences are taken into consideration during the formation of the value of increase. Thus the effort in providing the characteristic values field 72 is appreciably reduced, whilst additionally through consideration of the throttle flap angle merely an addition term is produced for increasing the computed target Through the comparison of the computed target value with the actual value of the throttle flap setting, in dependence on which the value of increase is determined, engine-specific conditions are taken into consideration and a very exact setting of the dashpot angle is ensured, since the movable abutment is always moved into the setting required under the prevailing conditions.

In another embodiment,, the regulating unit 42 can consist of two regulating units, which are active respectively within and outside the idling state. Within the idling state, one regulating unit is active for the setting of the idling speed, and the other unit is active for setting the dashpot angle outside the idling state. In that case, parameters specifically adapted to the respective regulations can be provided for both regulating units.

In the preceding, the method was described by reference to a device Which sets the throttle flap in the idling state by way of an electrically movable abutment. In travel operation, the throttle flap is raised from this abutment by a mechanical connection to the accel er ator ped a]. However, in other advantageous embodiments, the setting of the throttle flap is effected electrically in all operating ranges. The drive element 50 is then connected by way of a mechanical connection with the throttle flap 12 for the setting thereof. In the afore-described manner, a dashpot angle is fixed, below which the speed of change of the throttle flap in the direction of its rest position is reduced on release of the accelerator pedal. Thus, a dashpot function is realised. The determination of the angle in that case also takes place with the stated advantages. Moreover, the method is equally appli,cable to systems in which the setting of idling air and the dashpot function is realised by way of a bypass throttle flap.

Fig. 2 shows a flow chart for realisation of the afore-described method as part of a computer program. After the start of the program part, the afore-mentioned operating parameter magnitudes are entered in a first step 100 and it is interrogated in a step 102 whether the engine is in the idling state or not. The interrogation of the idling state is effected by way of the switch which is disposed at the abutment 52 and identifies whether the throttle flap is lying against the abutment. If this is the case, the target setting value is, in a step 104, determined on the basis of the operating parameter magnitudes and subject to the previously described adaptation.

Thereafter, an output value is.set in a following step 106 by way of a regulating function through comparison of the adapted target value with the actual position value of the movable abutment 52, the comparison being, for example, deduction of -the actual value from the target value. The program part is then terminated. If, on the other hand, the engine is not in the idling state, i.e. the throttle flap 12 is raised from the abutment 52, a deviation delta is computed in a step 108 from the difference between the target value determined by the preliminary control and the adaptation and the actual setting value of the throttle flap 12, and is used in a step 110 for determination of the value of increase. This value of increase is added in a step 112 to the target value determined by the preliminary control and the adaptation to form a new target value which, in the following step 106, is used in the aforesaid regulating for the setting of the abutment position.

is The method described in the foregoing is applicable not only to a movable throttle flap abutment, but also to movable control elements in bypass systems. The setting transmitters in that case can be potentiometers or other setting-detecting devices. In particular, the setting of the abutment outside the idling transmitter can be ascertained by a Hall pulse transmitter which counts the movement of the setting motor and derives a measure for its setting therefrom.

In an advantageous embodiment, the setting motor comprises a stepping motor. Its position is then detected by a step counter which counts the number of driving pulses.

1 - 12

Claims

1. A method for the control of a setting device in a vehicle, in which an electrical drive signal for the setting device is formed in dependence on a target value for and an actual value of the setting of the device and a predetermined setting signal is produced in at least one first operational state of the vehicle or caTonent thereof, wherein said setting signal in at least one predetermined operational situation has a substantially almost equal spacing from the setting of the setting device in at least one second operational state of the vehicle or the component.

2. A method as claimed in claim 1, wherein the at least one second operational state is the idling state of the vehicle engine and the at least one first operational state is the non-idling state of the engine.

3. A method as claimed in claim 1 or claim 2, wherein during the at least one second operational state the target value is determined in dependence on operating parameter magnitudes of at least one of the vehicle and the engine thereof in the sense of regulation of an operating parameter magnitude to a target value and wherein during the at least one first operational state the target value is determined starting from that for the at least one second operational,state.

13 -

4. A method as claimed in any one of the preceding claims, comprising the step of determining the target value during the at least one second operational state by ascertaining a preliminary control value from a first characteristic values field in dependence on operating parameter magnitudes of at least one of the vehicle and the engine thereof and by ascertaining a correction value from a second characteristic values field for correction of aging and drift phenomena, the correction value being linked with the preliminary control value to form the target value.

5. A method as claimed in claim 4 when appended to claim 2, wherein the target value for the at'least one second operational state outside the idling state is set into relation with the actual setting of a throttle flap of the engine and a value of increase in the target value for the at least one second operational state is determined from a third characteristic values field in dependence on the deviation of the throttle flap actual setting from the target value.

6. A method as claimed in claim 5, wherein the target value for the at least one first operational state is formed from the target value for the at least one second operational state and the value of increase.

7. A method as claimed in claim 2 or any one of claims 3 to 6 when appended to claim 2, wherein the setting device comprises as movable abutment to set the throttle flap when the vehicle accelerator pedal - 14 is released in the idling state, actuation of the throttle flap outside the idling state being by way of driver operation of the accelerator pedal and said at least one operational situation being contact of the throttle flap with the abutment.

8. A method as claimed in claim 2 or any one of claims 3 to 7 when appended to claim 2, wherein drive signal is prepared by regulating means comprising two regulating units respectively active in and out of the idling state.

9. A method as claimed in claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.

10. Control means for -control of a setting device in a vehicle, comprising regulating means for formation of an electrical drive signal for the setting device in dependence on a target value for and an actual value of the setting of the device and for producing a predetermined setting signal in at least one first operational state of the vehicle or component thereof, wherein said setting signal in at least one preset operational situation has a substantially almost equal spacing from the setting of the setting device in at least one second operational state of the vehicle or the component.

11. Control means substantially as hereinbefore described with reference to the accompanying drawings.

11. Control means as claimed in claim 10, the regulating means being so arranged that during the at least one second operational state the target value is determined in dependence on operating parameter magnitudes of at least one of the vehicle and the engine thereof in - the sense of regulation of an operating parameter magnitude to a target value and that during the at least one first operational state the target value is determined starting from that for the at least one second operational state.

12. Control means substantially as hereinbefore described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows 1. A method for the control of a setting device for the engine of a vehicle, wherein in the non-idling state of the engine an electrical drive Signal for the setting device is formed to cause the device to be driven into a predetermined setting, wherein at least in the idling state of the engine an electrical drive signal for the device is formed in dependence on a target value for and an actual value of the setting of the device, and wherein the predetermined setting of the device is so defined that the setting of the device in at least one predetermined operational situation of the vehicle has a substant- ially fixed spacing from the setting of the device in the idling state.

2. A method as claimed in claim 1, wherein during the idling state the target value is determined in dependence on operating parameter magnitudes of at least one of the vehicle and the engine thereof in the sense of regulation of an operating parameter magnitude to a target value and wherein during the non-idling state the target value is determined starting from that for the idling state.

3. A method as claimed in claim 1 or claim 2, comprising the step of determining the target value during the idling state by ascertaining a preliminary control value from a first characteristic values field in dependence on operating parameter magnitudes of at least one of the vehicle and the engine thereof and by ascertaining a correction value from a second characteristic values field for correction of aging and drift phenomena, the correction value being linked with the prel-iminary control value to form the target value.

4. A method as claimed in claim 3, wherein the target value for the idling state is set into relation with the actual setting of a throttle flap of the engine, and a value of increase in the target value for the idling state is determined from a third characteristic values field in dependence on the deviation of the throttle flap actual setting from the target value.

5. A method as claimed in claim 4, wherein the target value for the non-idling state is formed from the target value for the idling state and the value of increase.

6. A method as claimed in any one of the preceding claims, wherein the setting device comprises a movable abutment to set the throttle flap when the vehicle accelerator pedal is released in the idling state, actuation of the throttle flap in the non-idling state being by way of driver operation of the accelerator pedal and said at least one operational situation being contact of the throttle flap with the abutment.

7. A method as claimed in any one of the preceding claims, wherein the drive signals are prepared by regulating means comprising two regulating units respectively active in and out of the idling state.

8. A method as claimed in claim 1 and substantially as hereinbefore -Is described with reference to the accompanying drawings.

9. Control means for control of a setting device for the engine of a vehicle, comprising regulating means for formation in the nonidling state of the engine of an electrical drive signal for the device to cause the device to be driven into a predetermined setting and in the idling state of the engine of an electrical drive signal for the device in dependence on a target value for and an actual value of the setting of the device, wherein the predetermined setting of the device is so defined that the setting of the device in at least one predetermined operational situation of the vehicle has a substantially fixed spacing from the setting of the device in the idling state.

10. Control means as claimed in claim 9, the regulating means being so arranged that during the idling state the target value is determined in dependence on operating parameter magnitudes of at least one of the vehicle and the engine thereof in the sense of regulation of an operating parameter magnitude to a target value and that during the non-idling state the target value is determined starting from that for the idling state.