Method for operating a motor vehicle and corresponding motor vehicle

Abstract

A method for operating a motor vehicle includes operating the motor vehicle in a drive mode, a recuperation mode or a charging mode, wherein when operating the motor vehicle in the recuperation mode, a recuperation driving route driven during the recuperation mode and an associated recuperation energy amount are determined and are stored as driving route data in a driving route memory and/or are transmitted to an external data storage device; wherein when switching into the charging mode or when operating the motor vehicle in the charging mode an expected driving route of the motor vehicle is predictively determined and for the expected driving route the driving route data are read out from the driving route memory and/or are requested from external data storage device; wherein the target state of charge is set to a value which is determined from a maximal state of charge of the energy storage and the recuperation energy amount stored in the driving route data.

Claims

1. Method for operating a motor vehicle which has an electrical drive device, said method comprising: operating the motor vehicle in one of three modes, a drive mode in which an electric machine of the drive device is operated as motor, wherein by means of electrical energy withdrawn from an energy storage a torque that is directed toward an acceleration of the motor vehicle is provided, a recuperation mode in which the electric machine is operated as a generator, wherein a torque that is directed toward a deceleration of the motor vehicle is provided and electrical energy generated thereby is temporarily stored in the energy storage, and a charging mode in which the energy storage is charged with externally provided electrical energy until a predetermined target state of charge is achieved; when operating the motor vehicle in the recuperation mode, determining a recuperation driving route driven during the recuperation mode and an associated recuperation energy amount and storing the recuperation driving route and the recuperation energy amount as driving route data in a driving route memory or transmitting the driving route data to an external data storage device; when switching into the charging mode or when operating the motor vehicle in the charging mode predictively determining an expected driving route of the motor vehicle and for the expected driving route reading out the driving route data from the driving route memory or requesting the driving route data from the external data storage device; and setting the target state of charge to a value which is determined from a maximal state of charge of the energy storage and the recuperation energy amount stored in the driving route data.

2. The method of claim 1, wherein the determining of the expected driving route comprises generating a driving route profile of the motor vehicle and/or calendar using calendar data of a driver of the motor vehicle.

3. The method of claim 1, wherein the target state of charge is determined from a first prescribed state of charge or a second prescribed state of charge, wherein the target state of charge is set equal to the second prescribed state of charge when the second prescribed state of charge is greater than the first prescribed state of charge and is set equal to the first prescribed state of charge when the second prescribed state of charge is smaller than the first prescribed state of charge.

4. The method of claim 3, wherein the first prescribed state of charge corresponds to an amount of energy required for reaching the recuperation driving route stored in the driving route data.

5. The method of claim 3, wherein the second prescribed state of charge is set to the maximal state of charge minus the recuperation energy amount.

6. The method of claim 3, wherein the amount of energy required to reaching the recuperation driving route stored in the driving route data is added to the second prescribed state of charge.

7. The method of claim 1, wherein when multiple recuperation driving routes are present on the expected driving route only a recuperation driving route encountered first on the expected driving route is taken into account, or taking a recuperation driving route into account that is stored with a greatest recuperation energy amount.

8. The method of claim 3, wherein when multiple recuperation driving routes are present on the expected driving route the second prescribed state of charge is selected so that for the multiple recuperation driving route the state of charge of the energy storage present after each one of the recuperation driving routes is sufficient for reaching a respective following recuperation driving route.

9. The method of claim 1, further comprising providing the driving route data stored in the external data storage device to at least one further motor vehicle.

10. A motor vehicle, comprising an electric drive device, said motor vehicle being configured to be operated in three operating modes a driving mode in which an electric machine of the drive device is operated as motor, wherein by means of electrical energy withdrawn from an energy storage a torque that is directed toward an acceleration of the motor vehicle is provided, a recuperation mode in which the electric machine is operated as a generator, wherein a torque that is directed toward a deceleration of the motor vehicle is provided and electrical energy generated thereby is temporarily stored in the energy storage, and a charging mode in which the energy storage is charged with externally provided electrical energy until a predetermined target state of charge is achieved, said motor vehicle being configured when operating in the recuperation mode to determine a recuperation driving route driven during the recuperation mode and an associated recuperation energy amount and to store the recuperation driving route and the recuperation energy amount as driving route data in a driving route memory and/or to transmit the driving route data to an external data storage device, when switching into the charging mode or when operating in the charging mode to predictively determine an expected driving route of the motor vehicle and for the expected driving route to read out the driving route data from the driving route memory and/or to request the driving route data from the external data storage device, and to set the target state of charge to a value which is determined from a maximal state of charge of the energy storage and the recuperation energy amount stored in the driving route data.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which the sole FIGURE shows two diagrams, wherein in a first one of the diagrams an elevation course of a driving route of a motor vehicle and in a second one of the diagrams a state of charge of an energy storage of drive device of the motor vehicle.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(2) Throughout all the FIGURES, same or corresponding elements may generally be indicated by same reference numerals. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the figures are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.

(3) The FIGURE shows in an upper first diagram an elevation course of a driving route of a motor vehicle. Correspondingly a purely exemplary course for the height h over the driving route s is shown. In a lower second diagram on the other hand a state of charge (SOC: state of charge) over the driving route s is shown.

(4) The motor vehicle has an electric drive device, which includes an electric machine. By means of the electric machine for example a torque can be provided, which is directed toward an acceleration or a, deceleration of the motor vehicle. In particular it is provided that in a driving mode the electric machine is operated as a motor, wherein by means of energy withdrawn from an energy storage a torque that is directed toward an acceleration of the motor vehicle is provided. On the other hand in a recuperation mode the electric machine is operated as a generator, wherein a torque that is directed toward a deceleration of the motor vehicle is provided and electrical energy generated thereby is temporarily stored in the energy storage. In a charging mode the energy storage can be charged with the externally provided energy until reaching a predetermined target state of charge.

(5) It can be seen that the motor vehicle drives uphill on an exemplary driving route before a position s.sub.0. Hereby the state of charge of the energy storage decreases until a state of charge SOC.sub.0 is reached at the point s.sub.0. Purely exemplary the driving route has its greatest elevation h at this site s.sub.0. At the site s.sub.0 the charging mode is to be performed in order to charge the energy storage with externally provided electrical energy. In this respect for example a target state of charge of 100% can be used. Because the driving route extends downhill after the site s.sub.0, i.e., the elevation h decreases when continuing on the driving route s, it would be useful to operate the drive device in the recuperation mode in order to prevent an acceleration of the motor vehicle above a defined speed, i.e., to brake or decelerate the motor vehicle.

(6) Because in the recuperation mode the electric machine is operated as generator and correspondingly electrical energy is generated it is not possible to perform the recuperation mode at full energy storage, because the state of charge would have to be increased above a maximal state of charge, which corresponds to the state of charge of 100%. This is indicated purely exemplarily by a course 1.

(7) For performing the charging mode it is therefore preferably provided to set the target state of charge to a value that takes the subsequent driving route of the motor vehicle into account. For the here shown exemplary case it is advantageous to use the state of charge SOC.sub.1 as target state of charge. When the motor vehicle continues to drive along the driving route s in the recuperation mode starting from this state of charge the energy storage is fully charged at the end of the driving route or at the end of a downhill section of the driving route at a point s.sub.1. After the point s.sub.1 the driving route is for example approximately even so that at this location the drive device is operated in the driving mode. Correspondingly electrical energy is withdrawn from the energy storage so that its state of charge decreases.

(8) This is for example accomplished in that when performing the recuperation mode the recuperation driving route driven in the recuperation mode and the associated recuperation energy amount are determined and are stored as driving route data in a driving route memory and/or are transmitted to an external data storage device. During the drive of the motor vehicle it is thus detected whether the recuperation mode is performed for a section of the driving route. This section corresponds to the recuperation driving route which together with the recuperation energy amount generated on the recuperation driving route is stored or transmitted in the form of the driving route data.

(9) When now switching into the charging mode the expected driving route of the motor vehicle is predictively determined. For this expected driving route driving route data are read out from the driving route memory and/or are requested from the external data storage device. When for the expected driving route driving route data are already available, for example because they were either stored in the driving route memory or in the data storage device, the target state of charge for performing of the charging mode is set to a value which is determined from the maximal state of charge of the energy storage and the recuperation energy amount that is stored in the driving route data.

(10) In this way the recuperation energy amount generated on the expected driving route can be taken into account for the expected driving route for charging the energy storage with externally provided electrical energy. On one hand this has the advantage that the externally provided electrical energy amount required in the charging mode is reduced, which reduces the costs for the driver of the motor vehicle. In addition the torque directed toward the deceleration of the motor vehicle can still be reliably provided also during the recuperation mode that follows the charging mode. This would not be the case if the energy storage had already reached its maximal state of charge. At the least other means would have to be relied upon, for example actuating an operating brake of the motor vehicle.

(11) Generally it is irrelevant in which manner the driving route data are obtained. Particularly preferably they are detected and stored by the motor vehicle or multiple motor vehicles during the respective performance of a driving operation, i.e., in the driving route memory and/or the external data storage device. Subsequently the driving route data can be provided to at least one further motor vehicle or the multiple motor vehicles by the external data storage device. Thus in the case of a motor vehicle fleet a particularly efficient and comfortable operation of the motor vehicle can be accomplished.