DE10332668A1 - Control of a gear change in a manual transmission gearbox, wherein engine torque increase is retarded for a short period after beginning engagement of the clutch - Google Patents

Abstract

Method for controlling a gear change in a manual transmission gearbox in which during a first phase (t2-t2b) of matching the clutch torque and speed to that of a transmission shaft, the engine torque is maintained constant, while in a second phase (t2b-t3) the driving torque of the engine is increased with a delay after the beginning (t2) of the clutch engagement. An independent claim is made for a vehicle drive system.

Description

The The present invention relates to a switchable drive system, in particular for a Motor vehicle, with a switchable between several gear ratios Transmission, a motor and a clutch for interrupting a Traction between the engine and the transmission when a shift from a translation level to be made to another in the transmission, as well a method for controlling a gear change in such a drive system and components of such a drive system.

One complete Gear change in such a drive system includes the phases of opening the Clutch, performing a shift in the transmission and the closing of the clutch. In such a drive system is conventionally during opening of the Clutch the torque generated by the engine is limited to during the Shifting in the transmission to relieve the drivetrain. It is possible, that the switching process only after complete relief of the drive train begins; But he can also start the phase of opening the Clutch and the Abregelns the engine torque overlap in time.

at Such a drive system has the problem that in the course of a gear change the speed of a first connected to the engine Side of the coupling does not change or only slightly, whereas the second Page, which after switching with an altered gear ratio on above the Transmission driven parts such as the chassis of a motor vehicle coupled, an abrupt change the speed learns. If after completion of the shift, the clutch is closed again So, these two different rotating pages will come the clutch in contact. traditionally, will be during the closing the clutch engine torque already upshifted to a To prevent engine braking at the moment of clutch closing. During the closing The clutch adds an accelerating to this engine torque Moment, from the deceleration of the engine through the contact of the Continue fast rotating first side of the clutch with the slowly rotating second side results. This leads to a temporary acceleration increase, which adversely affects the switching impression. This impression can be suppress, by slowly closing the clutch after the shift, i.e. that transferable from the clutch Torque increased slowly is, or the engine torque is built up slowly, but extend this both measures the duration of the gear change. Since during the Changing gear the vehicle can not be accelerated should whose duration is kept as short as possible.

task The invention is a method for controlling a gear change in a manual transmission or a drive system for a motor vehicle which make it possible to To reduce the duration of the gear change to a minimum, while the To avoid acceleration pressure when switching up the gearbox from the deceleration of the engine during of closing the coupling results.

The Task is solved by that the step of closing the clutch and the upward control of the torque exerted by the engine An upshift is divided into a first phase in which the Coupling is transferred to a defined torque transmission state, while the engine is held at a substantially constant torque and a second phase, in which the driving torque of the Motors is upshifted, this second phase with a delay after Beginning of closing the coupling is initiated. So already during the first phase the The speed of rotation of the engine is equal to that of the transmission input then in the second phase the engine will jump up Tighten setpoint torque. The one for the Driver noticeable actual switching operation, i. closing the clutch is after already ended shortly after the start of the first phase, namely, if the clutch linings come so frictionally, so that the predicted torque transmission state is reached. On the other hand, as with the earlier procedures, the procedure is regulated of the engine parallel to closing the clutch on the defined torque transmission state plus possibly a plus Security admission, can the speed of rotation, due to the cumulative behavior the engine moments only at a much later date.

Preferably, in the first phase, the engine is supplied with a minimum amount of fuel that keeps its torque substantially zero, so that the engine can quickly follow a torque request beginning with the start of the second phase. It is also conceivable not to supply the engine with fuel during the first phase, so that the engine friction in addition to closing the clutch causes a deceleration of the engine. By such a negative torque, it is possible even faster to achieve the speed equalization between the engine and transmission. Of course, it may be useful in certain circumstances, the engine torque on ei when engaging in accordance with the invention constant positive value, which is likely to prolong the engagement process. In any case, the possibility of setting the engine torque in the context of the invention enables the switching speed to be influenced in a targeted manner.

To the Provide the respective constant engine torque can also Auxiliary sources, such as Compressor of an air conditioner or starter generator systems, are used, with the help of which the engine is braked either or can be accelerated.

Preferably In the first phase, the clutch is in a Drehmomentübertragunszustand with a quantitative torque transferred to the Setpoint corresponding to that exerted by the engine Torque for the time after closing the Clutch is fixed. This determination or determination takes place usually mathematically already before closing the clutch. That's how it is that transmitted from the clutch Torque, which is a possible acceleration of the vehicle fixed, in the two phases of the closing process of the clutch constant, so that an absolutely uniform acceleration course results. That is, already at the beginning of the closing of the clutch is the one Value of torque available, the driver of the ve hicle pretending by pedaling the accelerator pedal. The vehicle behaves Therefore, before the complete closing of the Clutch exactly as if the clutch is already closed and the gear change completed. That while of the gradual closing the clutch will, even though the torque of the motor is the setpoint has not yet reached, a torque corresponding to this target value transferred to the chassis and consequently also a corresponding acceleration course of the Vehicle achieved by the energy required for this kinetic Energy is removed from the rotational movement of the motor shaft.

The The invention also relates to a drive system for carrying out a Method as defined above, especially a control circuit of a Such a drive system and a data storage in which of a Data processing device, which is in particular the said control circuit can act to carry out the process program steps are stored. This data store can be activated by the control circuit be directly readable memory device, but also a disk like such as a floppy disk or CD-ROM, of which the program steps before their execution generally first transferred to a directly readable memory module Need to become.

Further Features and advantages of the invention will become apparent from the following Description of an embodiment with reference to the attached Characters. Show it:

1 a block diagram of a drive system in which the present invention is feasible;

2 the timing of speeds and torques in the drive system during a conventionally controlled gear change; and

3 the time course of the speeds and torques in inventive control.

1 shows very schematically a motor vehicle with a drive system according to the present invention. An Otto or diesel engine serves as an engine 1 , A crankshaft 2 this engine 1 is rotatably connected to a first page 3 ₁ a main clutch 3 , A second page 3 ₂ this clutch 3 is rotatably connected to an input side of a multi-stage gearbox 5 , An electronic control unit 7 is with the clutch 3 connected to open or close. This control unit 7 is also capable of the switching stage of the gearbox 5 set. She is with one on the crankshaft 2 arranged speed sensor 8th and with a speed sensor 9 connected to an output shaft connected to the landing gear 10 of the gearbox 5 is arranged.

The control unit 7 It can be designed as a fully automatic control unit that controls the manual transmission 5 is to be set automatically based on a number of operating parameters of the vehicle such as position of a driver-operated accelerator pedal, engine load, etc. and / or it may be a semi-automatic unit which serves to command the driver specifying a selected shift stage to receive and this in the manual transmission 5 adjust.

21:

eine von der Steuereinheit 7 einzustellende Ziel-Schaltstufe,

22:

die vom Drehzahlsensor 8 erfasste Drehzahl der Kurbelwelle 2 bzw. der mit ihr verbundenen ersten Seite 3₁ der Kupplung 3;

23:

eine Eingangsdrehzahl des Schaltgetriebes 5 bzw. die Drehzahl der zweiten Seite 3₂ der Kupplung 3;

24:

das von dem Motor 1 erzeugte Drehmoment; und

25:

das an der Hauptkupplung 3 übertragbare, je nach Öffnungs- oder Schließzustand der Hauptkupplung variable Drehmoment.

The diagram of 2 shows the time course of a plurality of operating parameters of the vehicle in the course of one by the control unit 7 in a conventional manner controlled gear changes. The curves indicate the following parameters:

21:

one from the control unit 7 to be set target switching stage,

22:

the speed sensor 8th recorded speed of the crankshaft 2 or the associated first page 3 ₁ the clutch 3 ;

23:

an input speed of the gearbox 5 or the speed of the second side 3 ₂ the clutch 3 ;

24:

that from the engine 1 generated torque; and

25:

that at the main clutch 3 transferable, depending on the opening or closing state of the main clutch variable torque.

Straight 26 is a zero line of torque. The transmission input speed according to the curve 23 can from the control circuit 7 according to 1 can not be measured directly, but is from the sensor 9 recorded speed in knowledge of the respectively set gear stage of the transmission 5 and calculate their gear ratio. A direct measurement by a speed sensor at the input of the gearbox 5 Of course, it would also be possible.

The time t ₀ denotes a beginning of the gear change. The course of the parameters shown before this time corresponds to a uniformly accelerated travel, the torques of the curves 24 . 25 are constant, and the speeds of the curves 22 . 23 are the same and increase evenly. At time t ₀ , the target switching stage of the curve changes 21 , it is irrelevant for the subsequent switching method, whether this change to an automatic decision of the control unit 7 or due to a driver command.

In a now beginning first phase of the gear change, up to the time t ₁ , the control unit moves 7 the torque 24 the main engine back and simultaneously relaxes the main clutch 3 so that the curve 25 to the zero line 26 drops. The curve 24 even goes back to a negative value, which corresponds to the fact that the engine 1 no longer drives, but experiences a delay by its own friction.

Accordingly, the speed of the engine also decreases 1 according to curve 22 from time t ₁ slowly.

During the period from t ₁ to t ₂ , the control unit performs 7 on the manual transmission 5 a shift in the course of which the new target shift stage is set. With the onset of traction in the new stage, the speed decreases 23 abruptly at the input of the gearbox to a value whose ratio is fixed to the previous speed by the gear ratios of the respective switching stages.

If at time t ₂ , the clutch is started to close again and the engine torque is high, the crankshaft speed will turn as shown 22 Slowly decelerated to the transmission input speed. At time t ₄ , the clutch is closed, the engine torque at a setpoint defined by the position of the accelerator pedal, and the gear change is completed.

3 shows a diagram analogous to that of 2 for an inventive controlled gear change. The steps of opening the clutch from t ₀ to t ₁ and shifting the transmission from t ₁ to t ₂ occur in the same manner as described above with reference to FIG 2 described. At time t ₂ , the control circuit begins 7 To provide the engine with a small amount of fuel that is such that it approximately compensates for internal friction losses of the engine, ie, makes the engine torque, which was negative during the previous shift, approximately zero. At the same time begins the control circuit, the clutch 3 swiftly close so far that the torque transmissible by the clutch, as through the curve 25 represented, assumes a value according to the determined by the position of the accelerator pedal engine torque before and after the gear change. The clutch reaches this torque at time t _2a and remains at this value until the time t _2b, the control circuit 7 determines that the difference between the crankshaft speed 22 and the transmission input speed 23 has fallen below a predetermined limit, in which the approximation of the speeds is almost completed. Now, the control circuit abruptly begins to up-regulate the engine torque to the setpoint and fully close the clutch so that at time t ₃ the engine delivers by combustion of fuel exactly that torque previously recovered by removal of kinetic energy from its moving parts has been.

Since the engine has already been supplied with fuel, even if in a small amount, before the start of the upshift, namely from time t ₂ , air-fuel mixture is in the intake manifold of the engine at time t _2b , so that this torque request of control circuit 7 can follow very quickly.

As with the control method according to the invention after the switching operation of the transmission 5 the crankshaft speed can be braked quickly - from t _2a to t _2b delivers this deceleration the entire acting on the chassis drive torque - can be significantly reduced with the inventive method required for the gear change time from t ₀ to complete closing of the clutch at t ₃ without causing an acceleration shock when closing the clutch. There the torque desired by the driver according to the position of the accelerator pedal is already available from the time t _2a , ie before the end of the gear change, gives the driver the impression that the gearshift is even faster, namely at time t _2a , is done.

1

Main engine

2

crankshaft

3

main clutch

4

auxiliary clutch

5

manual transmission

6

Auxiliary torque source

7

control unit

8th

Speed sensor

9

Speed sensor

10

output shaft

11

12

13

14

15

16

17

18

18

19

20

21

Target switching stage

22

Crankshaft speed

23

Transmission speed

24

Torque of 1

25

transmitted moment

26

zero line

Claims (10)

Method for controlling a gear change in a manual transmission ( 5 ), from which an input via a coupling ( 3 ) with a motor ( 1 ) and an output connected to a load, comprising the steps of: a) opening the clutch ( 3 ) (t ₀ - t ₁ ); b) switching the gearbox ( 5 ) from an original shift stage to a new shift stage in which the speed at the input of the transmission is lower at a constant speed of the output than at the original shift stage (t ₁ -t ₂ ); c) closing the clutch ( 3 ) and upshifting of the engine ( 1 ) exerted torque to a desired value (t ₂ - t ₃ ), characterized in that in a first phase (t ₂ - t _2b ) of step c) the clutch ( 3 ) is converted into a defined torque transmission state, while the engine ( 1 ) is maintained substantially at a constant torque and that a second phase (t _2b - t ₃ ) of step c), in which the driving torque of the engine ( 1 ), with a delay after the beginning (t ₂ ) of the closing of the clutch ( 3 ) is initiated. Method according to claim 1, characterized in that that in the first phase by the engine and / or an auxiliary source essentially no or a negative or a positive torque is produced. Method according to one of the preceding claims, characterized in that the method comprises determining the target value of the engine torque after closing the clutch ( 3 ). Method according to one of the preceding claims, characterized characterized in that the defined torque transmission state substantially is set to the target value of the engine torque. Method according to one of the preceding claims, characterized in that the first phase (t ₂ - t _2b ) ends as soon as a difference between the rotational speed ( 22 ) of the motor ( 1 ) and the ( 23 ) of the input of the transmission ( 5 ) falls below a threshold. Method according to one of the preceding claims, characterized characterized in that it is applied in a motor vehicle and that the load is formed by the chassis of the motor vehicle. Method according to claim 4 and claim 5, characterized characterized in that the setpoint based on the position of an accelerator pedal is calculated. Drive system for a motor vehicle, with a motor ( 1 ), a coupling ( 3 ), a manual transmission ( 5 ) and a control circuit ( 7 ) connected to the coupling ( 3 ) and the manual transmission ( 5 ) is coupled to the clutch ( 3 ) to open and close and the switching stage of the gearbox ( 5 ), characterized in that the control circuit ( 7 ), the coupling ( 3 ) and the manual transmission ( 5 ) to drive by a method according to any one of the preceding claims. Control circuit ( 7 ) for a drive system of a motor vehicle, characterized in that the control circuit ( 7 ), a coupling ( 3 ) and a manual transmission ( 5 ) of the drive system according to a method according to one of claims 1 to 6. Data memory for carrying out the method according to one of the preceding claims 1 to 8 with the aid of a data processing device ( 7 ), characterized in that steps of the method in a Pro stored in the data memory are coded.