DE102017222298A1 - Method for controlling a gear change and motor vehicle - Google Patents

Abstract

The invention relates to a method for controlling a gear change in a motor vehicle having a first drive unit, which has a gearbox and which drives a first axis and a second drive unit which drives a second axis, characterized in that a gear change is performed with the following steps - Detecting the output torque of the first drive unit, - Calculation of a target torque depending on the target gear, and - Implementation of a gear change of the first drive unit providing a supplementary torque by the second drive unit, wherein the supplementary torque from the current drive torque of the first drive unit and the target torque has been determined is.

Description

The invention relates to a method for controlling a gear change in a motor vehicle having a first drive unit which has a gearbox and which drives a first axis and a second drive unit which drives a second axis.

It is known to design hybrid vehicles in such a way that the internal combustion engine drives an axle and the electric motor drives a second axle. In particular, in a combination of an automated manual transmission with an electric motor on the second axis, it is known to let the electric motor so much torque transferred during gear changes that the gear change of the automated transmission can be made without interruption of traction.

Proceeding from this, it is an object of the present invention to provide a method and a corresponding control device with which the gear change is further improved.

• - Erfassen des aktuellen Antriebsmomentes der ersten Antriebseinheit,
• - Berechnung eines Zielmomentes in Abhängigkeit des Zielganges, und
• - Durchführung eines Gangwechsels der ersten Antriebseinheit und der Bereitstellung eines Ergänzungsmomentes durch die zweite Antriebseinheit, wobei das Ergänzungsmoment aus dem aktuellen Antriebsmoment der ersten Antriebseinheit und dem Zielmoment ermittelt worden ist.

To solve this problem, it is proposed in a method of the type mentioned above to carry out the following steps:

• Detecting the current drive torque of the first drive unit,
• - Calculation of a target torque depending on the target gear, and
• - Implementation of a gear change of the first drive unit and the provision of a supplementary torque by the second drive unit, wherein the supplementary torque has been determined from the current drive torque of the first drive unit and the target torque.

In this method, the current drive torque is detected and from this, but not simply kept constant by the second drive unit of this drive torque, while the first drive unit, the gear change is made. Rather, the current drive torque is transferred to a target torque, which differs from the current drive torque. Accordingly, the additional torque output by the second drive unit is determined as a function of the target torque.

The output torque is that moment that exists before the gear change is initiated. In addition to the output torque after engagement of the clutch or during engagement and the current drive torque of the first drive unit to be considered, while designed with the clutch, the first drive unit contributes no torque.

Preferably, the target torque can be determined by means of the target ratio of the gearbox. The torque provided by the first drive unit differs at the same speed for the output gear and the target gear. Accordingly, the target torque can be determined predictively taking into account the target gear ratio of the target gear. Furthermore, the target torque can be determined by means of the predicted speed of the internal combustion engine after the shift and / or the output ratio of the gearbox.

In particular, the following relationships apply:

The moment M on the wheel _{M_VKM_pre} before the gear change results as the product of the torque provided by the first drive unit with the output gear ratio: $${\text{M}}_{\text{Rad\_VKM\_pre}}={\text{M}}_{\text{VKM}}\times {\text{i}}_{\text{pre}},$$

After the gear change, the moment M _{Rad_VKM_Post} arriving at the wheel _results from the then delivered torque of the first drive unit M _{VKM_Post} and the target transmission i _Post : $${\text{M}}_{\text{Rad\_VKM\_Post}}={\text{M}}_{\text{VKM\_Post}}\times {\text{i}}_{\text{post Office}},$$

Since the speed of the internal combustion engine changes during the shift, the moment M _{VKM_Post} does not correspond to M _{VKM_pre} . Preferably, M _{VKM_post should} therefore be _predicted as a function of the accelerator pedal position and the target rotational speed determined from the target ratio. The torque applied to the wheels by the engine after the gear change is also called the target torque.

The prediction of M _{VKM_Post} makes sense, since, as can be seen from the consideration of the motor characteristics shown below, otherwise a deviating, depending on the initial situation too low or too high, moment M _{VKM_post} would be estimated.

Preferably, the target torque can be determined as a function of the accelerator pedal position. The target speed can be predicted better, and thus the target torque. This, in turn, flows into the supplementary torque, as a result of which the determination of the supplementary torque is also further improved.

Advantageously, the target torque can be adjusted as a function of a change in the accelerator pedal position. In addition to the training just presented this relates to the change in the accelerator pedal position and not the starting position. The supplementary moment depends on how described above not only from the target torque, but also from the output torque. However, the output torque is determined inter alia by the accelerator pedal position. If the accelerator pedal position changes, the output torque changes as it were. Whether a change in the accelerator pedal position is regarded as a change in the target torque, the output torque or the supplemental torque is actually incidental, since a difference torque is ultimately determined from the mentioned moments, which changes as a function of the change in the accelerator pedal position. To which output variable one adds the difference is above all a change of the view, but not of the differential torque to be considered.

Preferably, a target torque may be used that is smaller than the current drive torque. This is particularly provided in a method for controlling a gear change in an upshift. Alternatively, in a method for downshifting the gear, a target torque greater than the output torque may be used.

Advantageously, a first drive unit with an internal combustion engine can be used. Further preferably, a first drive unit can be used with an automated manual transmission. Preferably, a second drive unit can be used with an electric motor. A drive unit can thus also include the transmission itself in addition to an internal combustion engine, furthermore, a differential can be included as a component of the drive unit. Whether the front axle or the rear axle is driven via the first drive unit is irrelevant.

In addition, the invention relates to a device for controlling the driving force of a motor vehicle with at least one control unit. The control unit is characterized in that it is designed to carry out the method described.

In addition, the invention relates to a motor vehicle with a control device. The motor vehicle is characterized in that the control unit is designed as described.

In particular, this includes that the control unit and the motor vehicle have all the objective features that are necessary for carrying out the method.

Thus, the motor vehicle on two driven axles, wherein a first drive unit and a second drive unit are present. The motor vehicle may have other non-driven or driven axles. Furthermore, the first drive unit preferably has an internal combustion engine and / or a manual transmission and / or an automated manual transmission. The second drive unit advantageously comprises an electric motor.

The control unit comprises a detection module for detecting the output torque of the first drive unit, a calculation module for calculating a target torque in response to a target gear and a control module for performing a gear change of the first drive unit to provide a supplementary torque, wherein the supplementary torque is provided by the calculation unit.

Advantageously, the calculation unit can adjust the supplementary torque as a function of a change in the accelerator pedal position. The other advantageous embodiments described in connection with the method can also be found in the control unit and thus also in the motor vehicle.

• 1 ein Kraftfahrzeug,
• 2 ein erstes Zeitverlaufsdiagramm,
• 3 ein zweites Zeitverlaufsdiagramm, und
• 4 ein Kennlinienfeld.

Further advantages, features and details of the invention will become apparent from the following description of exemplary embodiments and figures. Showing:

• 1 a motor vehicle,
• 2 a first timing diagram,
• 3 a second timing diagram, and
• 4 a characteristic field.

1 shows a motor vehicle 1 with a first drive unit 2 and a second drive unit 3 , The first drive unit comprises an internal combustion engine 4 and a manual transmission 5 , The first drive unit 2 further comprises a clutch actuator for between an internal combustion engine 4 and manual transmission 5 lying clutch and a Getriebeaktuator for actuation of the gearbox 5 , The first drive unit may be referred to in this embodiment as an automated manual transmission.

The second drive unit 3 is preferably designed as an electric motor. The first drive unit 2 drives the axle 6 on, of which only the wheel 7 is shown while the second drive unit 3 the axis 8th drives, from which the wheel 9 is shown.

2 shows a flow of the circuit without a prediction of the target torque. The axis shows 10 the time and the axis 12 the moment in Nm in relative units. The curve 14 gives the moment of the first drive unit 2 on, the curve 16 the supplementary torque provided by the second drive unit and the curve 18 the target moment. The target moment 18 has it after the time 20 to which the gearshift begins, a burglary. After the time 22 the gear change is completed. After the time 23 the transfer of the moment is complete. The moment of the first drive unit 2 at the time 22 is the target moment and moment of the first drive unit 2 at the time 20 the output torque. These are both on the curve 14 , The between times 20 and 22 present moments of the second drive unit 3 are referred to as supplementary moments.

3 shows another timing diagram, in contrast to 2 the target moment is estimated in advance. It is through the curve 14 again the moment of the first drive unit 2 described and through the curve 16 the supplementary torque generated by the second drive unit 3 provided. In that the goal moment 26 the curve is estimated 18 much smoother, there is no burglary of the motor vehicle 1 overall driving moment. That the goal moment 26 below the output torque 24 is, is desired in an upshift, while still increasing the speed of the wheels.

4 shows a map to take into account the position of the accelerator pedal and the target speed. It is against the axis 32 indicating the engine speed and the axle 12 , the moment, here of the internal combustion engine 4 indicates five turns 34 . 36 . 38 . 40 and 42 shown. The curve 34 describes the torque to be delivered as a function of the engine speed for an engagement of the accelerator pedal at 20%. The curve 36 for an indentation at 40%, the curve 38 for an indentation at 60%, the curve 40 for an accelerator depression at 80% and the curve 42 when the accelerator is engaged at 100%. Average values can be calculated. On the basis of this characteristic map, an output torque can thus be defined for each engine speed and each accelerator pedal position. When the accelerator pedal position is changed, an output torque and thus also a difference torque can be determined on the basis of the characteristic diagram. This flows into the calculation of the supplementary torque 30 on.

LIST OF REFERENCE NUMBERS

1

motor vehicle

2

first drive unit

3

second drive unit

4

Internal combustion engine

5

manual transmission

6

axis

7

wheel

8th

axis

9

wheel

10

axis

12

axis

14

Curve

16

Curve

18

Curve

20

time

22

time

23

time

24

output torque

26

target torque

28

current moment

30

supplement moment

32

axis

34

Curve

36

Curve

38

Curve

40

Curve

42

Curve

Claims (11)

Method for controlling a gear change in a motor vehicle (1) having a first drive unit (2) which has a gearbox (5) and which drives a first axle (6) and a second drive unit (3) which has a second axle (8) driving, characterized in that a gear change is performed with the following steps: - detecting the output torque of the first drive unit (2), - calculating a target torque (26) depending on the target gear, and - performing a gear change of the first drive unit (2) below Provision of a supplementary torque by the second drive unit (3), wherein the supplementary torque from the current drive torque of the first drive unit (2) and the target torque (26) has been determined. Method according to Claim 1 , characterized in that the target torque (26) by means of the target ratio of the gearbox (5) is determined. Method according to Claim 1 or 2 , characterized in that the target torque by means of the rotational speed of the internal combustion engine (4) and / or the Output ratio of the gearbox (5) is determined. Method according to one of the preceding claims, characterized in that the target torque (26) is determined as a function of the accelerator pedal position. Method according to one of the preceding claims, characterized in that the target torque (26) and / or the output torque (24) and / or the supplementary torque (30) is adjusted in response to a change in the accelerator pedal position. Method according to one of the preceding claims, characterized in that a target torque (26) is used, which is smaller than the output torque (24). Method according to one of the preceding claims, characterized in that a first drive unit (2) with an internal combustion engine (4) is used. Method according to one of the preceding claims, characterized in that a first drive unit (2) is used with an automated manual transmission. Method according to one of the preceding claims, characterized in that a second drive unit (3) is used with an electric motor. Device for controlling the driving force of a motor vehicle with at least one control unit, two driven axles (6, 8) and at least two drive units (2, 3), characterized in that the control unit is designed to carry out the method according to one of the preceding claims. Motor vehicle with a control device, characterized in that the control unit according to Claim 9 is trained.

Images