Method for setting operating parameters of a drive unit of a motor vehicle

Abstract

A method for setting operating parameters of a drive unit (1) of a motor vehicle, wherein a driving strategy (9) is calculated in advance at least over a specific distance to be covered by the motor vehicle and is applied to set operating parameters of the drive unit (1), and wherein the precalculated driving strategy (9) can be changed by actuating a control element (12) that controls the drive unit (1) as a function of its actuation path between a low load and a high load, characterized in that the control element (12) can be controlled in at least three consecutive operating ranges (13, 14, 15) via the actuation path of the control element (12), wherein the precalculated driving strategy (9) is not applied in a lower operating range (13) with a low load of the drive unit (1) and in an upper operating range (15) with a high load of the drive unit (1).wherein the pre-calculated driving strategy (9) is applied in a central operating range (14) with a medium load of the drive unit (1), wherein the operating range (14) in which the pre-calculated driving strategy (9) is applied has a plurality of sub-ranges distributed over the actuation path of the control element (12), wherein the pre-calculated driving strategy (9) is executed with different dynamics depending on which of the sub-ranges the control element (12) is located in, and wherein the control element (12) provides feedback to an operator actuating the same via a transition between the successive operating ranges (13, 14, 15).

Description

[0001] The invention relates to a method for adjusting operating parameters of a drive unit of a motor vehicle according to the preamble of claim 1.

[0002] DE 10 2007 036 794 A1 discloses a method for determining the driving strategy of a motor vehicle. In this method, a corridor for a possible target driving speed with an upper and a lower speed limit is defined for a given route. Such methods are used, for example, to plan driving strategies that optimize fuel consumption or driving strategies with the best possible dynamics, whereby predictive knowledge of route information, such as road gradient, curve curvature, etc., should be known.

[0003] If the driver is supported by a suitable control system, the implementation of this predicted driving strategy can, in principle, be entirely handled by the driver of the vehicle. In this case, the driver acts as both the longitudinal and lateral dynamics controller, i.e., they are responsible for acceleration and braking on the one hand, and for steering on the other.

[0004] Alternatively, the predicted driving strategy can also be implemented by the vehicle using automatic longitudinal dynamics control. In this case, the driver only controls the lateral dynamics, i.e., they steer the vehicle. Such a strategy enables better reproducibility and transferability of the predicted savings or dynamics potential to the actual operation of the vehicle.

[0005] However, for safety and comfort reasons, the driver must still be able to intervene in the strategy at any time, i.e. the driver must have the option of overriding the vehicle's automatic longitudinal dynamics control.

[0006] DE 101 48 344 A1 describes a method and a device for controlling a drive unit of a motor vehicle, in which a drive unit is controlled by means of an operating element, preferably an accelerator pedal, in different operating ranges of the accelerator pedal, taking into account variable secondary loads of the drive unit.

[0007] From DE 10 2006 046 218 A1 a method for controlling the drive train of a motor vehicle is known, in which a disengagement range of the accelerator pedal is determined depending on various factors, such as driver's request, vehicle speed, engine speed and friction losses, whereby this disengagement process enables the vehicle to "sail".

[0008] DE 43 44 369 A1 discloses an electronic accelerator pedal in which the accelerator pedal travel is divided into two angular ranges. A first angular range covers the power range below a specified value, while a second angular range can only be operated with increased actuation force. The division of the two angular ranges is variable.

[0009] DE 10 2007 036 794 A1 and DE 43 05 737 A1 disclose further prior art.

[0010] It is an object of the present invention to provide a method and a device for adjusting operating parameters of a drive unit of a motor vehicle, in which the driver has the possibility of adapting a driving strategy calculated in advance to his individual driving dynamics requirement.

[0011] According to the invention, this object is achieved by the method according to claim 1.

[0012] Due to the at least three consecutive control areas along the actuation path of the control element, which produce different effects when controlling the drive unit of the motor vehicle, the driver operating the control element has the option of either applying the pre-calculated driving strategy or, alternatively, by switching to the corresponding control area of the control element via the actuation path of the control element in which the pre-calculated driving strategy is not applied, of controlling the drive unit of the motor vehicle or its operating parameters themselves. The control element provides the driver with feedback when a transition from one control area to the other has taken place, so that the driver is always aware of which of the control element's control areas they are in and, consequently, whether the pre-calculated driving strategy is being applied or not.This can be achieved by pressure points that can be moved along the actuation path of the control element, i.e. a change in the force curve that can be felt by the driver.

[0013] According to the invention, the central operating range with a medium drive unit load, in which the predicted driving strategy is applied, has several sub-ranges distributed over the actuation path of the control element, whereby the predicted driving strategy is executed with different dynamics depending on which of the sub-ranges the control element is located in. This allows a certain dynamics to be achieved even within the operating range in which the predicted driving strategy is applied, without exceeding the limits of the predicted driving strategy.

[0014] Accordingly, three separate operating areas are provided over the actuation path of the control element, wherein in the lower operating area with a low load on the drive unit and in the upper operating area with a high load on the drive unit the pre-calculated driving strategy is not applied, and wherein in the middle operating area with a medium load on the drive unit the pre-calculated driving strategy is applied.This means that both in the case where the driver wishes to drive more slowly than would be the case with a pre-calculated driving strategy due to road conditions, for example, and in the case where the driver wishes to drive faster than with the pre-calculated driving strategy due to a planned overtaking maneuver, the driver can intervene in the operating parameters of the drive unit, whereby the pre-calculated driving strategy is implemented in a central operating range via the actuation travel of the control element, which the driver can easily maintain by actuating and subsequently holding the control element.

[0015] In order to avoid excessively large jumps at the boundary between the at least three operating areas, which could potentially result in a loss of comfort for the driver and the other vehicle occupants, a very advantageous development of the invention can provide for transition areas to be present between the successive operating areas, in which transition areas a comprehensible transition is achieved between the application of the pre-calculated driving strategy and the waiver of its application.

[0016] If feedback to the control element is provided by changing the actuation force required to operate it, this provides a particularly simple way to provide feedback to the driver. This creates a haptic control element that clearly informs the driver whether the predicted driving strategy is being applied.

[0017] Further advantageous embodiments and developments of the invention emerge from the remaining subclaims. An embodiment of the invention is explained in more detail in the following description and drawing. It shows: Fig. 1 a schematic representation of a possible sequence of the method according to the invention Fig. 2 is a diagram in which the load applied to a drive unit of a motor vehicle is plotted against the actuation travel of the control element of the device according to the invention; and Fig. 3 a diagram in which the actuating force required to operate the control element is plotted against the actuating travel of the control element.

[0018] In Fig. 1 shows a diagram illustrating the sequence of a method for setting operating parameters of a drive unit 1 of a motor vehicle (not shown in its entirety). By means of a control device 2, in which, in the present case, various vehicle data 3, a route profile 4, speed limits 5, comfort criteria 6, safety criteria 7, and the traffic 8 prevailing during the journey of the motor vehicle can be recorded and processed, a driving strategy 9 is calculated in advance, at least for a specific route to be covered by the motor vehicle, and is applied to set operating parameters of the drive unit 1. Essentially, however, the driving strategy 9 can also be calculated in advance using only digitized map data.By means of the driving strategy 9 it would in principle be possible to control the drive unit 1 and thus the motor vehicle via a longitudinal controller 10, i.e. a device for controlling the longitudinal dynamics of the motor vehicle, i.e. the braking and acceleration thereof, i.e. to set the operating parameters of the drive unit 1 to the values desired for operating the motor vehicle.

[0019] However, in order to be able to take into account the driver's request of an operator, in particular a driver, of the motor vehicle, designated by the reference numeral 11, a control element 12 is provided which acts on the drive unit 1 via the driving strategy 9 and the longitudinal controller 10. The control element 12 can therefore be used to control the drive unit 1 or to set certain operating parameters of the drive unit 1 depending on the driver's request 11. The drive unit 1 can be a conventional internal combustion engine, but hybrid, electric, or other drives can also be used. In the present case, the drive unit 1 also includes a transmission (not shown in detail) or a similar device, the operating parameters of which can also be set by the control element 12 if necessary.The control element 12, which can be designed, for example, as a foot-operated accelerator pedal, but also as a steering column lever attached to a steering wheel or a similar device, can be adjusted in a conventional manner over a specific actuation path, which, depending on the design of the control element 12, can also be an actuation angle. By actuating the control element 12, the drive unit 1 can be operated between a low load and a high load, thereby changing the pre-calculated driving strategy 9. A low load on the drive unit 1 also includes no load, which can occur, for example, in the so-called coasting mode of the motor vehicle. The term "high load" also includes a full load on the drive unit 1.The amount of the load depends essentially on the design of the respective drive unit 1 and can therefore vary greatly from one motor vehicle to another.

[0020] As shown in the diagram of Fig. 2, in the embodiment shown, three separate operating areas, namely the operating areas 13, 14 and 15, are provided across the actuation path of the control element 12 plotted on the x-axis, in which the operating parameters of the drive unit 1 are influenced in different ways or which produce a different effect in the control of the drive unit 1 of the motor vehicle. The load applied to the drive unit 1 is plotted on the y-axis, with a scale of 0% for no actuation path covered or no applied load to 100% for the actuation path completely covered, i.e. fully actuated control element 12, or maximum load.

[0021] In the present case, the pre-calculated driving strategy 9 is not applied in the lower operating range 13, in which a low load is applied to the drive unit 1, and in the upper operating range 15, in which a high load is applied to the drive unit 1, i.e. in the two operating ranges 13 and 15, the driver's inputs to the control element 12, i.e. the driver's request 11, are passed directly to the drive unit 1, which implements the driver's request 11 accordingly. However, in the middle operating range 14, in which a medium load is applied to the drive unit 1, the pre-calculated driving strategy 9 is applied, i.e. in this operating range the driver does not directly influence the longitudinal dynamics of the motor vehicle, with one exception described below. In this embodiment, the driving strategy 9 is therefore only adapted in the middle operating range 14.

[0022] In addition, the operating area 14 in which the pre-calculated driving strategy 9 is applied can have several individual sub-areas distributed over the actuation path of the control element 12, and the pre-calculated driving strategy 9 can be executed with different dynamics depending on which of the sub-areas the control element 12 is located in. Fig. In this case, the load of the drive unit 1, shown in the form of a curve in FIG. 2, over the actuation travel of the control element 12 could be a staircase. By approaching the control element 12 toward the upper or lower limit of the central operating range 14, the driver can adapt the precalculated driving strategy 9 toward lower or higher dynamics. Furthermore, adaptation toward more or less dynamics is possible in all operating ranges 13, 14, or 15.

[0023] In the present exemplary embodiment, respective transition areas 16 and 17 are further provided between the successive operating areas 13, 14, and 15, in which a comprehensible transition between the application of the precalculated driving strategy 9 and the abandonment of its application is achieved. In the present case, a transition area 16 is provided between the lower operating area 13 and the middle operating area 14, and a further transition area 17 is provided between the middle operating area 14 and the upper operating area 15.

[0024] In the present exemplary embodiment, three consecutive operating areas are provided along the actuation path of the control element 12. However, it is also possible to provide a different number of operating areas in which the driver's commands to the control element 12 are implemented in different ways. More than three operating areas could also be provided; for example, the operating area 15 could be provided with an additional kick-down function. The position of the transition area(s) 16 and 17 can vary during operation, particularly during longitudinally controlled operation, according to the pre-calculated driving strategy. Since deceleration phases can occur during longitudinally controlled operation, it may be useful, in combination with a haptic force feedback to the driver described below, to leave areas 14 and / or 16 in the direction of shorter pedal travel. Fig. 2, the load or tractive force during random driving is shown with the solid line and the load or tractive force for generating dynamics during longitudinally controlled driving is shown with a dash-dotted line.

[0025] The limits of operating ranges 13, 14, and 15, as well as the transition ranges 16 and 17, can in principle be shifted via the actuation travel of control element 12. The reasons for such a shift of the limits of operating ranges 13, 14, and 15 and / or their effects can be stored in the driving strategy. For example, this can be the degree of tractive force, with positive or negative characteristics, the positive or negative relative acceleration, or the position of the pressure point, the compression step, or the limit of the dynamic range.

[0026] In order to inform the driver which of the operating areas 13, 14 and 15 of the control element 12 he is in and thus to inform him whether the pre-calculated driving strategy 9 is being applied or whether he himself has full influence on the longitudinal dynamics of the motor vehicle with the setting of the control element 12 he has made, the control element 12 provides the person operating it, in this case the driver, with haptic feedback about a transition between the successive operating areas 13, 14 and 15. This can be done, for example, by changing the actuation force required to actuate the control element 12, so that the driver feels that he has switched from one operating area to the other. Of course, additional acoustic and / or visual displays are also possible within a dashboard of the motor vehicle (not shown) or at other suitable locations.In this context, the relationship between the actuation path of the control element 12 and the force to be applied to actuate the control element 12 can be freely programmable, so that the illustrated operating areas 13, 14 and 15 as well as the transition areas 16 and 17 and, if appropriate, also the sub-areas can be arranged as desired over the actuation path of the control element 12.

[0027] In Fig.Figure 3 shows a possible relationship between the actuation force of control element 12, i.e., the accelerator pedal force, and the actuation travel of control element 12, i.e., the pedal travel, shown with the solid line including hysteresis. In the operating area 14, in which the longitudinal control takes place, three force levels can be provided, for example, for three levels of the driver's desired dynamics. To represent decelerations that are deliberately planned or required at short notice due to corresponding traffic events, it may be useful to shift the pressure point of control element 12, which the driver perceives, towards smaller pedal travels in order to achieve the desired dynamics. This achieves a return of the foot during deceleration with a constant foot force applied by the driver, but with a relaxed foot position. In the subsequent pulling phase, the foot then moves back to its starting position or "normal position."This force curve during a deceleration phase is indicated by reference numerals 13', 14', 16', and 17' and by the dashed line. The longitudinally controlled range of the driver's foot position can be shifted according to the driving strategy specifications to provide feedback on current or expected operating points while maintaining a constant driver input, since the pressure point, driver's foot position, and characteristic curve are shifted synchronously.

[0028] The control element 12 is therefore provided with a device (not shown) which makes it possible to give the operator actuating the control element 12 feedback when the control element 12 switches between the operating areas 13, 14 and 15. For example, a control element 12 designed as an accelerator pedal can be designed by appropriately arranging springs or spring assemblies so that a higher force is required at one or more points along the actuation path. Decoupling the springs would also be possible in this case in order to suspend the described control of the drive unit 1 via the control element 12, i.e. not to apply it. Alternatively or additionally, the use of one or more electric motors to generate the force counteracting the actuation of the control element 12 would also be conceivable.

[0029] Of course, the described method and device can also adjust other operating parameters of the drive unit 1 and / or other elements of the motor vehicle in addition to those described. For example, a braking intervention can be performed in this way if an obstacle is detected on the route of the motor vehicle.

Claims

[1] Method for setting operating parameters of a drive unit (1) of a motor vehicle, wherein a driving strategy (9) is calculated in advance at least over a specific distance to be covered by the motor vehicle and is applied to set operating parameters of the drive unit (1), and wherein the precalculated driving strategy (9) can be changed by actuating a control element (12) which controls the drive unit (1) as a function of its actuation path between a low load and a high load, characterized bythat the control element (12) can be controlled in at least three consecutive operating ranges (13, 14, 15) via the actuation path of the control element (12), wherein in a lower operating range (13) with a low load of the drive unit (1) and in an upper operating range (15) with a high load of the drive unit (1), the pre-calculated driving strategy (9) is not applied, wherein in a middle operating range (14) with a medium load of the drive unit (1), the pre-calculated driving strategy (9) is applied, wherein the operating range (14) in which the pre-calculated driving strategy (9) is applied has a plurality of sub-ranges distributed over the actuation path of the control element (12), wherein the pre-calculated driving strategy (9) is executed with different dynamics depending on which of the sub-ranges the control element (12) is located in,and wherein the control element (12) provides feedback to an operator operating the same via a transition between the successive operating areas (13, 14, 15). [2] Method according to claim 1, characterized by that transition areas (16, 17) are present between the successive operating areas (13, 14, 15), in which a comprehensible transition between the application of the pre-calculated driving strategy (9) and the waiver of its application is achieved. [3] Method according to claim 1 or 2, characterized by that the feedback to the control element (12) is given by a change in the actuating force required to actuate it. [4] Method according to one of claims 1 to 3, characterized by that the driving strategy (9) is calculated in advance using digitized map data. [5] Method according to one of claims 1 to 4, characterized bythat the limits of the operating areas (13,14,15) can be moved via the actuation path of the control element (12).

Images