DE102009053731A1 - Method for controlling and/or regulating drive unit of motor vehicle, involves reducing high switching speed when actual acceleration is smaller than lower limit and acceleration capacity in higher gear is larger than actual acceleration - Google Patents

Abstract

The method involves assigning a high switching speed (1) to a gear of an automatic transmission of a drive unit of a motor vehicle. An upshift is executed in a higher gear of the transmission when actual speed (3) of the drive motor reaches the high switching speed, and actual acceleration (7) of the vehicle is determined. Acceleration capacity (9) is determined in the higher gear of the transmission, and the high switching speed is reduced when the actual acceleration is smaller than a lower limit and the Acceleration capacity in the higher gear is larger than the actual acceleration.

Description

The invention relates to a method for controlling and / or regulating the drive unit of a motor vehicle, wherein the drive unit has a drive motor and an automatic transmission with multiple gear ratios, wherein at least one of the gear ratios is assigned a shift up speed, wherein an upshift is performed in a higher gear when the current speed of the drive motor reaches at least one of the upshift speeds and wherein the current acceleration of the motor vehicle is determined.

From the DE 102 53 809 A1 a method for controlling the drive unit of a motor vehicle is known. The drive unit has a variably controllable drive motor and a variably controllable, automated transmission. The control characteristics of the drive motor and the transmission are defined via associated control characteristics. Depending on changed operating conditions, an adaptation of both the control characteristic of the drive motor and the control characteristic of the transmission takes place. For this purpose, sensors are provided for detecting the changed operating condition. To detect a change in the driving style, motion sensors are provided for measuring the current acceleration. With the motion sensors, the vehicle movement is detected. Furthermore, a GPS receiver and inclination sensors are provided to distinguish between lowland, mid mountain and high mountain journeys and to provide appropriate adjustments in the event of a detected change in the driving environment. The sensors are connected to a control unit, by means of which both the control characteristic of the drive motor and the control characteristic of the transmission can be adapted to the changed operating conditions. The following control maps are available for selection: a control map for an average "standard" driving style, a control map for a sporty-dynamic "sport" driving style, a control map for a comfortable "comfort" driving style and a control map for a fuel-efficient "eco" driving. In this case, an interpolation between the existing control maps can be provided. It is known that the control maps have upshift speeds, with an upshift to a higher speed step being performed when the current speed of the drive motor reaches the upshift speed.

The method known in the prior art is not yet optimally designed. The upshift speed at a full throttle is also known as full throttle switching point or kickdown switching point. Full throttle switch points and also kickdown switch points are not designed for an acceleration maximum. Furthermore, an optimal adaptation to the topography of the route to be traveled can not always be achieved by interpolation of different control maps, since the topography of the routes to be traveled when setting the control maps are not known. Furthermore, the power loss of different drive motors differs when driving off different height profiles. If a motor vehicle drives uphill, z. B. from 2000 meters above sea level to over 4000 meters above sea level, a turbo engine loses part of its torque as a drive motor in the upper rpm range. This can lead to the motor vehicle not accelerating even in the full throttle position of the accelerator pedal.

The invention is therefore based on the object a method for controlling and / or regulating the drive unit of a motor vehicle in such a way and further, so that a sub-optimal adaptation of the control characteristic of the drive unit in a temporarily occurring engine power loss can be avoided.

This object is achieved according to the invention in that an acceleration capability is determined in the higher gear, wherein the upshift speed is reduced when the current acceleration is less than a lower limit and the acceleration capacity in the higher gear is greater than the current acceleration. This has the advantage that at a low motor power z. B. when driving on a mountain pass a lower upshift speed is determined when the original upshift speed is no longer achievable with the accelerator pedal in a full throttle position and additionally the acceleration capacity is greater than the current acceleration. The present method is a learning algorithm for determining the upshift speed, in particular the full throttle shift points. Due to the reduction of the upshift speeds, these "new upshift speeds" are again achieved even with low engine power. If a drive motor loses power at altitude, the current acceleration will approach zero. Preferably, the ratio of the actual acceleration and the acceleration capacity is formed in the higher gear. This ratio can then be used to determine whether the acceleration in the higher gear is greater than the current acceleration. The ratio of the current acceleration and the acceleration capacity in the higher gear, especially in the next higher gear - the so-called connection - will therefore also approach the value 0, if the current acceleration is the Value 0 approaches. A reduction in the upshift speed is performed only when the aforementioned ratio is smaller than a lower limit of, for example, 5%. If the acceleration in the higher gear has positive values, the upshift speed is reduced, which may lead to an upshift. The motor vehicle then accelerates again. The method described here is not intended to determine the optimum switching point due to the greatest possible acceleration capacity, but rather it is intended to determine the highest possible rotational speed point of the drive motor in the current gear step, the so-called upshift rpm. The upshift speed is initially set in the range of the "red speed line", although there is an increased acceleration capacity in a higher gear. The method makes it possible to reduce the upshift speed if the current acceleration falls below a lower limit, in particular approaches the value 0 and assumes small values compared to the acceleration capacity in a higher gear. A reduction in the upshift speed is stopped when the upshift is performed. Each gear can be assigned a shift up speed. An upshift may be performed when the current speed of the drive motor reaches the upshift speed associated with the current speed step. Preferably, however, the minimum of all upshift speeds of the gear ratios is formed and an upshift is performed when the current speed of the drive motor reaches this minimum of all upshift speeds. Furthermore, the method has a strategy for increasing the upshift speeds. For example, after a new approach, the upshift speed can be increased. During this approach, if the accelerator pedal is moved to the full throttle position without the upshift speed being decreased, the upshift speed is increased and this new, increased upshift speed is stored. On the following starts, the upshift speed can be further increased until a reduction in the upshift speed again takes place. The disadvantages mentioned above are therefore avoided and achieved corresponding advantages.

There are now a variety of ways to design and further develop the inventive method for controlling and / or regulating the drive unit of a motor vehicle. For this purpose, reference may first be made to the claims subordinate to claim 1. In the following, a preferred embodiment of the invention will now be explained in more detail with reference to the drawing and the associated description. In the drawing shows:

1 in a schematic diagram, a plurality of state variables of a motor vehicle during an upshift from a second gear to a third gear, and

2 in a schematic diagram, the state variables of the motor vehicle in one of 1 subsequent acceleration operation during the upshift from the second speed to the third speed.

The following is a method for controlling and / or regulating the drive unit (not shown) of a motor vehicle (not shown) based on 1 and 2 explained.

The drive unit, not shown, has a drive motor and an automatic transmission with multiple gear ratios. Each gear is preferably an initially determined upshift speed 1 assigned. In the 1 and 2 is the upshift speed 1 assigned to the second gear. In both 1 and 2 is the upshift speed 1 (y-axis) over the time axis 2 (x-axis) applied. The timeline 2 in 1 shows a time interval between 11.5 seconds and 22. seconds. A period between the 32nd second and the 40th second is in 2 shown.

An upshift to a higher gear is performed when a current speed 3 of the drive motor, the upshift speed 1 reached. The speed 3 achieved (cf. 1 ) between second 20 and second 20.5 the upshift speed 1 and thus a switching point 4 , In 2 becomes a switching point 5 reached between 38.5 seconds and 39 seconds. In 1 and 2 it can be seen that at the switching point 4 respectively. 5 a switching recommendation 11 changes abruptly. The previously continuously increased speed 3 of the drive motor falls after the switching point 4 respectively. 5 , ie after changing the switching recommendation 11 and the thereby triggered upshift from.

The upshift speed 1 is particularly dependent on a position 6 the accelerator pedal. The position 6 the accelerator pedal is in 1 and 2 also plotted over time. The position 6 the accelerator pedal corresponds in the illustrated period of Kickdownstellung. The upshift speed 1 is in particular "quasi" a so-called "kickdown switching point". The accelerator pedal is for this purpose preferably substantially 100% pushed through. The present method is preferably carried out only when the position 6 the accelerator pedal takes the kickdown position or the position 6 above a certain threshold (not shown).

In the 1 and 2 is also the current acceleration 7 of the motor vehicle over the time axis 2 applied. Furthermore, in 1 and 2 the current speed 8th of the motor vehicle shown. The acceleration 7 can out of the speed 8th be determined by derivation and / or measured by acceleration sensors, not shown.

1 shows that despite the maximum position 6 of the accelerator pedal the acceleration 7 , especially from the 14th second decreases and the speed 8th remains essentially constant or the current acceleration 7 approaches the value 0.

In 2 takes the current acceleration 7 before the switching point 5 also off and also approaches the value 0. The speed 8th stays close to the switching point 4 respectively. 5 essentially constant.

The aforementioned disadvantages are now avoided by an acceleration capability 9 is determined in a higher gear, wherein the upshift speed 1 is reduced when the current acceleration 7 is less than a lower limit and the acceleration capacity 9 in the higher gear is greater than the current acceleration 7 , This has the advantage that the driving strategy when using the automatic transmission to a particular temporarily occurring engine power z. B. is adapted by the topography of the route. The reduced upshift speed 1 is achieved after a corresponding reduction even with a temporarily occurring low motor power. An acceleration capacity 9 The drive motor can be reduced, for example, by moving the motor vehicle at a particularly high altitude. If the drive motor is designed as a turbo engine, this can in particular lead to a collapse of the torque at high speeds.

The acceleration capacity 9 can be relatively accurately determined, in particular estimated in the different operating conditions of the motor vehicle or the drive motor and the automatic transmission. The acceleration capacity 9 Here, the acceleration capacity (the vzw., determined / average estimated acceleration) of the motor vehicle in the next higher gear - here the third gear - expresses. The acceleration capacity 9 is preferably a function of the currently selected gear, the current speed 3 and the current acceleration 7 determined, in particular estimated or calculated in particular with a control unit and / or a microprocessor. The expected acceleration capacity 9 in the higher gear ratio can also be obtained in particular from simulations and stored as a characteristic or calculated based on drive models, the simulations and the drive models take into account the respective drive motor and the gear used, the ride height of the motor vehicle and / or slope of the route. The acceleration capacity 9 This also takes into account the topography of the route. On a slope is with a smaller acceleration capacity 9 to be expected than in the plane at a same operating point of the drive motor.

Preferably, the ratio 10 from the current acceleration 7 and the acceleration capacity 9 formed in the higher gear. A reduction in the upshift speed 1 is done when the ratio 10 is less than a lower limit. The lower limit is in 1 not shown, but this lower limit is reached in the 18th second. From the 18th second is the upshift speed 1 reduced. The lower limit may be, for example, 5%. Based on the relationship 10 can be detected, whether the acceleration 7 greater or smaller than the acceleration capacity 9 is. When the drive motor loses power at altitude, the current acceleration is approaching 7 to the value 0. If the current acceleration 7 As the value approaches 0, the ratio approaches 10 (see. 1 ) from the current acceleration 7 , and the acceleration capacity 9 also the value 0. The use of the ratio 10 has the advantage of reducing the upshift speed 1 is not performed, though the current acceleration 7 is approaching the value 0, but the acceleration capacity 9 in the - higher - connection is still smaller than the current acceleration 7 , In this case, the ratio 10 bigger and no smaller. The reduction of the upshift speed 1 takes place vzw. gradually. The upshift speed 1 can be gradually or gradually reduced at regular intervals. For example, the upshift speed 1 be reduced in steps or steps of 30 revolutions per minute. After a certain time interval then each of the upshift speed 1 decreased by a certain level or step. On average, this results preferably in a linear reduction of the upshift speed 1 (see. 1 ). The time interval may be, for example, 50 milliseconds.

It does not try the highest possible current acceleration 7 to reach. In this case would have to be switched if the current acceleration 7 under the acceleration capacity 9 falls; This happens already at about 14.5 seconds. The upshift speed 1 is only diminished when the current acceleration 7 smaller is lower than, for example, less than 0.2 m / s ² . The lower limit is preferably undershot, for example, for a certain period of time, for example 50 milliseconds, after which a further condition is queried as to whether the acceleration capability 9 in the higher gear is greater than the current acceleration 7 ,

As a further condition for reducing the upshift speed 1 is preferably queried whether the acceleration capacity 9 in the transition or in the higher gear is greater than a lower limit. This lower limit can also be 0.2 m / s ² .

Preferably, the upshift speed becomes 1 only reduced if a waiting time has elapsed since the last switching operation. During this waiting period, no switching operations have been carried out. The waiting time may be 500 milliseconds, for example.

As a further boundary condition is preferably for checking the reduction of the Hochschaltdrehzahl 1 evaluated whether the current speed 3 of the drive motor is greater than a minimum speed. This minimum speed represents a lower limit below which the upshift speed 1 is not reduced. This minimum speed may be, for example, 3000 revolutions per minute. In a further embodiment of the method, the minimum speed below which the upshift speed 1 is not reduced, depending on the current engine power and / or height or other factors are set individually.

As a further boundary condition, it is preferably evaluated whether the brake has not been actuated for a certain time, for example for 500 milliseconds.

As a further condition for reducing the upshift speed 1 is preferably queried whether the accelerator pedal for a certain period of time - for example, 500 milliseconds - has not been significantly moved. For example, it is possible to query whether the gas pedal has not been moved over a gradient threshold for the time span. The gradient threshold preferably measures the speed of movement of the accelerator pedal.

Further, the upshift speed becomes 1 only reduced when the position 6 of the accelerator pedal is above a threshold value. In particular, the position should 6 the accelerator pedal correspond to the kickdown position.

If all or at least some of the above boundary conditions are met, for example, an electronic switch can be set, wherein the upshift speed 1 only corrected when this electronic switch is set.

If, after an evaluation of the boundary conditions, a release for the reduction of the upshift speed 1 is issued, the upshift speed 1 for example, reduced in increments of 30 revolutions per minute. This reduced upshift speed 1 can then be fed into a maximum speed monitoring. When the upshift speed 1 to the current speed 3 has fallen, automatically an upshift is triggered by the maximum speed monitoring module. This is at the switching point 4 happen. The reduction of the upshift speed 1 is then stopped. The process has a new upshift speed 1 "Learned".

When re-starting (cf. 2 ) becomes the switching point 5 already on reaching the newly learned upshift speed 1 achieved, in particular without the upshift speed 1 would have to be further reduced.

For each gear is preferably a separate upshift speed 1 Are defined. In one embodiment of the method, an upshift may be performed when the current speed 3 of the drive motor, the respective engaged gear ratio associated upshift speed 1 reached.

Preferably, however, an upshift is already performed when the current speed 3 the minimum of all upshift speeds 1 reached. That means an upshift is performed when the current speed 3 greater than or equal to an upshift speed associated with the current gear 1 or a gearshift speed associated with another gear 1 is.

In this way, the reduction of the upshift speed 1 easy to perform. If the engine power decreases in height at high engine speeds, is switched up earlier and earlier. If the motor vehicle drives steadily uphill, for example from 2,000 meters above normal 0 to 4,000 meters above normal 0, then the upshift speeds become 1 decreases to the current acceleration 7 and the current speed 8th to increase it again. The current speed 8th and the current acceleration 7 are after reaching the switching point 4 respectively. 5 increased again (cf. 1 . 2 ).

Preferably, the upshift speed becomes 1 again increased (not shown), if in a previous approach, especially in the last approach of the motor vehicle, the upshift speed 1 was reduced and in the current approach the upshift speed was not reduced. Especially can the upshift speed 1 be increased after a journey by, for example, 30 revolutions per minute. Should during the journey the position 6 the accelerator pedal a full throttle position or kickdown position and achieve this "full throttle" with the increased upshift speed 1 without performing a reduction in the upshift speed 1 done, so is the increased upshift speed 1 stored and adopted as a learning value. The next approach then begins with an increased by, for example, 30 revolutions per minute upshift speed 1 ,

An approach is defined so that the motor vehicle has stood briefly and then starts again. It is sufficient if the speed has reached the value 0. There are vzw. so-called "learning starts" and so-called "test drives" are performed. During a learning approach, the upshift speed becomes 1 not increased. After a test start, the upshift speed 1 as described below:
Whether in the last approach a reduction in the upshift speed 1 can be stored in a status value. If during the last approach the upshift speed 1 has been reduced, the next approach is carried out as "Lernanfahrt". In particular, the following approaches are carried out as "Lernanfahrten". If the current speed is a certain speed range below the upshift speed 1 achieved - for example, a speed range of 120 revolutions per minute below the upshift speed 1 -, The achievement of this speed range is preferably stored in another status value. When the upshift speed 1 during this learning approach, despite reaching the speed range below the upshift speed 1 has not been reduced, at least one "inspection approach". If now during one of the test drives the new increased upshift speed 1 is reached, the upshift speed 1 further increased. For example, further test approaches gradually increase the respective upshift speed by 30 revolutions per minute 1 , Should during a test drive the upshift speed 1 be reduced, so below again a "learning approach" is performed. When increasing the upshift speed 1 becomes the upshift speed 1 preferably compared to an upper limit. When the upper limit is reached, the upshift speed becomes 1 not further increased.

LIST OF REFERENCE NUMBERS

1

Upshift speed

2

timeline

3

rotation speed

4

switching point

5

switching point

6

Position of the accelerator pedal

7

acceleration

8th

speed

9

acceleration

10

relationship

11

shift recommendation

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10253809 A1 [0002]

Claims (10)

Method for controlling and / or regulating the drive unit of a motor vehicle, wherein the drive unit has a drive motor and an automatic transmission with a plurality of gear steps, wherein at least one of the gear steps has a shift-up speed ( 1 ), wherein an upshift to a higher gear is performed when the current speed ( 3 ) of the drive motor at least one of the upshift speeds ( 1 ) and where the actual acceleration ( 7 ) of the motor vehicle, characterized in that an acceleration capacity ( 9 ) is determined in the higher gear, wherein the upshift speed ( 1 ) is reduced when the current acceleration ( 7 ) is less than a lower limit and the acceleration capacity ( 9 ) in the higher gear ratio is greater than the current acceleration ( 7 ). Method according to claim 1, characterized in that a ratio ( 10 ) from the current acceleration ( 7 ) and the acceleration capacity ( 9 ) is formed in the higher gear and a reduction in the Hochschaltdrehzahl ( 1 ) is carried out only if the ratio ( 10 ) is less than a lower limit. A method according to claim 1 or 2, characterized in that a reduction of the upshift speed ( 1 ) is only performed if a certain waiting time has already elapsed after a last switching operation. Method according to one of the preceding claims, characterized in that the upshift speed ( 1 ) is gradually reduced, wherein a reduction of the upshift speed ( 1 ) is performed only when a certain time interval since the last reduction of the upshift speed ( 1 ) has passed. Method according to one of the preceding claims, characterized in that a reduction of the upshift speed ( 1 ) is carried out only if the acceleration capacity ( 9 ) is greater than a lower limit. Method according to one of the preceding claims, characterized in that a reduction of the upshift speed ( 1 ) is performed only when a brake of the motor vehicle has not been operated for a certain period of time. Method according to one of the preceding claims, characterized in that the accelerator pedal has not been moved for a certain period of time, in particular a gradient threshold of the accelerator pedal has not been exceeded in a certain period of time. Method according to one of the preceding claims, characterized in that a reduction of the upshift speed ( 1 ) is performed only when the accelerator pedal is in a position ( 6 ) above a threshold value, in particular if the position ( 6 ) corresponds to a kickdown position. Method according to one of the preceding claims, characterized in that the upshift speed ( 1 ) is increased, if in a previous approach the Hochschaltdrehzahl ( 1 ) and, in the current approach, the upshift speed ( 1 ) was not reduced. Method according to one of the preceding claims, characterized in that the upshift speed ( 1 ) is compared with a lower limit and when the lower limit is reached, the upshift speed ( 1 ) is not further reduced and / or the upshift speed ( 1 ) is compared with an upper limit and, when the upper limit is reached, the upshift speed ( 1 ) is not increased further.

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