DE10335775B4 - Drive system for a car and method for controlling a gear change - Google Patents

Abstract

Drive system for a motor vehicle, comprising a gearbox (5) which can be switched between several gear ratios, a main engine (1), a clutch (3), of which a first side (3 ₁ ) with the main engine (1) and a second side (3 ₂ ) is connected to the transmission (5), and an on the first side (3 ₁ ) of the clutch (3) connectable auxiliary torque source (6), characterized in that a control unit (7) is arranged, the auxiliary torque source (6) in the open Switching the state of the clutch (3) when the speed (22, 22 ', 22'') of the first side of the clutch in a given direction deviates from a target speed, wherein the control unit of an upcoming switching operation as a target speed with the corresponding a gear ratio corresponding to the switching operation multiplied speed (23) of the second side (3 ₂ ) selects.

Description

The The present invention relates to a drive system for a motor vehicle and method for controlling a gear change, with an intermediate several translation stages reversible gearbox, a main engine and a. Clutch, from the one first side with the main engine and a second one is connected to the transmission, and whose two sides are different from each other are separable to a traction between the main engine and to interrupt the transmission and so in the transmission a switching operation to enable. One complete Gear change in such a drive system includes the phases of opening the clutch, of performing a shift in the transmission and the closing of the Clutch.

at Such a drive system has the problem that in the course of a gear change, the speed of the first side of the clutch is not or only little changes, whereas the second side, which after changing gears with a changed ratio to over the Transmission driven parts such as the chassis of a motor vehicle coupled, an abrupt change the speed learns. If after completion of the switching operation, the clutch easily is closed again, so these two come at different speeds rotating sides of the clutch in contact. When the clutch is fast is closed, the speed of the engine abruptly to the Adjusted input side of the transmission, resulting in the case of a Motor vehicle by a for the occupants noticeable, unpleasant jerk noticeable. One slow closing extended the duration of the gear change in which the vehicle does not accelerate can be, and is therefore also undesirable.

The DE 197 04 153 A1 relates to a drive system, in particular for a motor vehicle with an internal combustion engine, at least one electric machine that can apply torque to the internal combustion engine; and a controller that controls the electric machine in idling operation of the internal combustion engine so as to counteract a change in the idling speed by applying a driving or braking torque.

In order to avoid the jerk when shifting and still allow a quick gear change, is in DE 197 09 417 A1 proposed a drive system for a motor vehicle, wherein during a switching operation of the engine is brought by an electronic control circuit to a target speed, which enables a smooth closing of the clutch.

A such procedure is in the case of a downshifting of the transmission effective, that is, for gently closing the clutch after the shift the speed of the engine must be increased. Such a speed increase is easily realizable in a very short time by the control circuit controls the fuel supply of the engine accordingly. But when when shifting up the gearbox to gently close the clutch After the switching process, a reduced speed of the motor required there are no funds available to reduce this could cause the same speed as an increase in speed. The Speed at which a speed reduction of the engine reaches is essentially determined by its interior Friction; However, this should be in the interests of economic Operating as low as possible.

The The consequence of this is that, in particular in an upshift of the Gear the for a desired one Alignment of the speeds required on both sides of the clutch Time is quite long. Correspondingly long takes the entire gear change, which is particularly disturbing then noticeable when upshifting during an acceleration process of the vehicle takes place and the acceleration is eliminated, as long as the clutch is open is.

task The invention is a drive system for a motor vehicle and method to create a gear change that makes it possible to to speed up the gear change, especially when upshifting while still a jerk-free, material-friendly closing of the clutch enable.

The Task is solved by a drive system with the features of claim 1 and a Method with the features of claim 11.

Accordingly, the invention, in particular a drive system for a motor vehicle, with a switchable between several gear ratios gear, a main engine, a clutch, a first side of the main engine and a second side is connected to the transmission, and one on the first side the clutch connectable auxiliary torque source, characterized in that a control unit is adapted to turn on the auxiliary torque source in the open state of the clutch when the speed of the first side of the clutch in a given direction deviates from a target speed and the auxiliary torque source as soon as these speeds are adjusted to a fixed positive or negative delta.

In In this context, it should be noted that when aligning the engine speed, e.g. in normal operation regularly to achieve a continuous Traction connection, is driven to a value slightly above the target speed is. The reason for this is the fact that the engagement process takes a certain time, in which the engine, e.g. because of his Friction, lose speed. In contrast, is often in the Overrun mode set a speed that is below the target speed located. This will ensure that it is in overrun mode does not come to any engine accelerating moment.

The Auxiliary torque source can, depending on the design, driving or braking Effect or both effects have optionally.

Very is advantageous, as an auxiliary torque source selectively to the Main engine to use connectable second engine, for other reasons is installed in the vehicle.

When Braking auxiliary torque source comes e.g. a compressor one Air conditioning of the motor vehicle or its alternator into consideration. Such a compressor or such an alternator are indeed known, but not their targeted, temporary use for adjusting the speeds of the two sides of the clutch, regardless of a current cooling or electricity requirement.

When Auxiliary torque source also comes in a starter-generator system consideration; such can optionally be used to generate a drive or a braking effect, depending on the direction of the switching process used become.

one According to a simple embodiment, the control unit of the drive system according to the invention set as by turning on the auxiliary torque source target speed to be reached, the instantaneous speed of the second page to choose the clutch. Such a choice can be made and the adjustment made, after the shift into the desired gear ratio in the transmission is done.

one further developed embodiment provides that the load useful auxiliary torque source from the control circuit is already switched on when the clutch is open, an upshift but still pending. That's it possible, with the braking of the first side required during upshifting to start the clutch already, even before the shift took place and the resulting speed difference between the two sides the clutch is observable, and the time after completion of the Shifting is needed to equalize the speeds, continues to reduce. Accordingly, a useful as a drive auxiliary torque source from the control unit in the presence of a downshift yet be turned on before completion of the downshift to shorten the time required to equalize the speeds.

there can reach the target speed of the first side of the clutch be estimated before the switching operation by the current Speed of the second side of the clutch with a through the executed Switching operation specified transmission factor is multiplied and the auxiliary torque source regardless of whether the switching process is complete, is switched off again when this target speed he is enough. However, it is also possible in the Period before completion of the shift operation, the first side of the clutch to brake or accelerate unregulated and as the target speed only then to choose the speed of the second side when the switching operation is done.

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

1 a block diagram of a drive system according to the invention;

2 the time course of rotational speeds and torques in the drive system during a gear change according to a first embodiment of the invention;

3 the time course of the speeds and torques according to a second embodiment; and

4 the course of these speeds and torques according to a third embodiment of the invention.

1 shows very schematically a motor vehicle with a drive system according to the present invention. An internal combustion engine, in particular a gasoline or diesel engine forms a main engine 1 , A crankshaft 2 this main engine 1 is rotatably connected with the first pages 3 ₁ . 4 ₁ a main clutch 3 and an auxiliary clutch 4 , Second pages 3 ₂ . 4 ₂ this coupler gene 3 . 4 are rotatably connected to an input side of a multi-stage gearbox 5 or an auxiliary torque source 6 , here the compressor of an air conditioning system of the motor vehicle. An electronic control unit 7 is with the clutches 3 . 4 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-actuated accelerator pedal, engine load, etc., or it may be a semi-automatic unit serving 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 Hauptkupplung 3;
• 23: eine Eingangsdrehzahl des Schaltgetriebes 5 bzw. die Drehzahl der zweiten Seite 3₂ der Hauptkupplung 3;
• 24: das von der Hauptkraftmaschine 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 of the control unit 7 controlled gear change according to a first embodiment of the invention. The curves indicate the following parameters:

• 21 : one from the control unit 7 to be set target switching stage,
• 22 : that of the speed sensor 8th recorded speed of the crankshaft 2 or the associated first page 3 ₁ the main clutch 3 ;
• 23 : an input speed of the gearbox 5 or the speed of the second side 3 ₂ the main clutch 3 ;
• 24 : that of the main 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 their transmission 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 main engine 1 no longer drives, but experiences a delay by its own friction.

Accordingly, the speed of the main 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. Accordingly, the speed goes 23 at the entrance of the gearbox 5 abruptly back. The control unit 7 detects a discrepancy between the speed 22 the first page 3 ₁ the main clutch 3 and the speed 23 the second page 3 ₂ and closes at time t _2, the auxiliary clutch 4 so that the auxiliary torque source 6 braking on the main engine 1 acts. The crankshaft speed 22 Now decreases rapidly, until the time t _3, the difference to the speed 23 at the transmission input has become so low that the control unit 7 the auxiliary clutch 4 triggers again and instead begins, the main clutch 3 close again and the torque of the main engine 1 drive up, as through the curves 24 . 25 shown. When these torques reach their stationary values again at time t ₄ , the gear change is completed.

3 shows a diagram analogous to that of 2 for a gear change according to a second Ausgestal direction of the invention. In this second embodiment, the control unit starts 7 immediately after opening the main clutch 3 at time t ₁ and before the switching operation of the gearbox 5 , the auxiliary clutch 4 close and so the crankshaft 2 to break. The result is a curve of the crankshaft speed according to the curve 22 ' , The speed starts already from the time t ₁ to decrease sharply, so that the time t ₃ ', where the difference of the speeds according to curves 22 ' and 23 is so small that can be started with the closing of the main clutch, earlier than the time t ₃ according to 2 , At time t ₃ 'opens the control circuit 7 the auxiliary clutch 4 and turns on the auxiliary torque source 6 so again off.

In this embodiment of the method, the problem is that if before the start of the switching operation of the gearbox 5 with the deceleration of the crankshaft 2 is started, the input speed of the gearbox 5 to which the crankshaft speed must be adjusted, can be measured at any point of the drive system and therefore is not yet available as a parameter for the controller. The braking effect by the auxiliary torque source 6 must therefore be so low that, regardless of which the gear ratios of the transmission 5 are, between which is switched, the crankshaft speed does not fall below the transmission input speed after the switching operation. It is obvious that with such a weak braking the shortest possible switching times can not be achieved.

4 shows the sequence of a again accelerated switching operation according to a third embodiment, again in the form of a diagram analogous to 2 and 3 , In this embodiment, the tax unit calculated 7 based on the speed sensor 9 on the output shaft 10 detected speed and the transmission ratio of the target shift stage already in the time interval t ₀ to t _1, the speed, which after completion of the switching operation at the input of the gearbox 5 will adjust. Once at time t _1, the main clutch 3 is open, the control unit brakes 7 the crankshaft 2 strong, by up to complete closing of the auxiliary clutch 4 , and so long until at time t ₂ '' the crankshaft 2 - Before the completion of the shift of the gearbox - reached the speed that was calculated as the input speed of the gearbox after switching. At time t ₂ ", the auxiliary clutch becomes 4 - before the end of the switching process - reopened. So can immediately after the switching operation of the gearbox 5 , at time t ₃ '', start the main clutch 3 to close again.

It It is obvious that the control processes described above are not the use of an air conditioning compressor, as an example mentioned, but with the help of any other type of selectively connectable second engine or even a simple friction brake or another type of brake executable.

Claims (14)

Drive system for a motor vehicle, with a gearbox that can be switched between several gear ratios ( 5 ), a main engine ( 1 ), a coupling ( 3 ), from which a first page ( 3 ₁ ) with the main engine ( 1 ) and a second page ( 3 ₂ ) with the gearbox ( 5 ) and one on the first page ( 3 ₁ ) of the coupling ( 3 ) connectable auxiliary torque source ( 6 ), characterized in that a control unit ( 7 ), the auxiliary torque source ( 6 ) in the open state of the clutch ( 3 ) when the speed ( 22 . 22 ' . 22 '' ) of the first side of the clutch in a given direction deviates from a target speed, wherein the control unit of an impending shift as the target speed multiplies the speed multiplied by a gear ratio corresponding to the shift speed ( 23 ) the second page ( 3 ₂ ) chooses. Drive system according to claim 1, characterized in that the control unit ( 7 ) is set up as the target speed ( 23 ) the second page ( 32 ) to choose . Drive system according to one of the preceding claims, characterized in that the auxiliary torque source ( 6 ) is useful as a load and by the control unit ( 7 ) is turned on when the speed of the first page ( 3 ₁ ) of the coupling ( 3 ) is higher than the target speed. Drive system according to one of the preceding claims, characterized in that the auxiliary torque source ( 6 ) is useful as a load and by the control unit ( 7 ) is turned on when the clutch ( 3 ) is open and an upshift is imminent. Drive system according to one of the preceding claims, characterized in that the auxiliary torque source ( 6 ) is useful as a drive and by the control unit ( 7 ) is turned on when the speed of the first side of the clutch ( 31 ) is lower than the second one. Drive system according to claim 5, characterized in that the auxiliary torque source ( 6 ) is useful as a drive and by the control unit ( 7 ) is turned on when the clutch ( 3 ) is open and a downshift is imminent. Drive system according to Claim 1 or one of Claims 3 to 6, characterized in that the auxiliary torque source ( 6 ) is a second engine. Drive system according to claim 7, characterized in that the auxiliary torque source ( 6 ) is a compressor of an air conditioner or an alternator of the motor vehicle. Drive system according to claim 7, characterized in that the auxiliary torque source ( 6 ) is a starter-generator system. Drive system according to claim 1 or 4, characterized in that the auxiliary torque source ( 6 ) is a brake. Method for controlling a gear change in a drive system with a gearbox that can be switched between several gear ratios ( 6 ), a main engine ( 1 ) and a clutch 3 ), from which a first page ( 31 ) with the main engine ( 1 ) and a second page ( 32 ) with the gearbox ( 6 ), comprising the steps of: a) releasing the coupling ( 3 ; t ₀ -t ₁ ); b) performing a switching operation in the transmission ( 6 ; t ₁ -t ₂ ) to change its translation stage; c) applying an auxiliary torque (t ₂ -t ₃ ; t ₁ -t ₃ '; t ₁ -t ₂ ") to the first side (31) of the clutch ( 3 ) until the speeds ( 23 ) of the two sides ( 32 ) assimilate; d) closing the clutch ( 3 ; t ₃ - t ₄ ; t ₃ '- t ₄ ; t ₃ "-t ₄ ). Method according to claim 11, characterized in that that the shift is an upshift and the assist torque a braking torque is. Method according to claim 11, characterized in that that the shift is a downshift and the assist torque is a drive torque. Method according to one of claims 11 to 13, characterized that with exercising the Assist torque is started before the completion of the switching operation.