METHOD FOR OPERATING A HYBRID VEHICLE AND HYBRID VEHICLE

Abstract

A hybrid vehicle has a drive comprising an internal combustion engine, has an energy converter comprising an electric machine that can be operated for recuperation purposes, and has a control unit that is operatively connected to an operating element, to the drive and to the energy converter. The hybrid vehicle glides when the drive is not in the propulsion mode of operation and with an electric motor operated in a recuperation intensity stage in a first drive state. Based on the control unit having made the determination that the operating element was actuated, the determination is made in the control unit as to whether a condition is present, whereby the duration of the actuation of the operating element is determined and it is determined in a comparison that the duration is below the time threshold value. If the condition is present, a changeover is made from the first drive state to a second drive state in which the hybrid vehicle is then operated.

Claims

1. A method for operating a hybrid vehicle having a drive comprising an internal combustion engine, having an energy converter comprising an electric machine that can be operated for recuperation purposes, and having a control unit that is operatively connected to an operating element, to the drive and to the energy converter, the method comprising the following steps: gliding the hybrid vehicle when the drive is not in a propulsion mode of operation and when an electric motor is operated in a recuperation intensity stage in a first drive state, determining, by the control unit, an actuation of the operating element, determining, by the control unit, whether a condition is present based on the actuation, and if the condition is present, changing over from the first drive state to a second drive state, and operating the hybrid vehicle in the second drive state, wherein the determining of the presence of the condition comprises: determining a duration of the actuation of the operation element, comparing the duration to a time threshold value, and determining whether the duration is below the time threshold value.

2. The method for operating a hybrid vehicle according to claim 1, further comprising, in the first drive state, operating the hybrid vehicle by engaging the drive while free-wheeling and/or operating the hybrid vehicle with the drive switched off.

3. The method for operating a hybrid vehicle according to claim 1, further comprising, in the second drive state, switching on the drive and operating the drive in the propulsion mode of operation, or operating the drive in the propulsion mode of operation when the drive has already been switched on.

4. The method for operating a hybrid vehicle according to claim 1, further comprising, in the second drive state, operating the electric motor in a different recuperation intensity stage.

5. The method for operating a hybrid vehicle according to claim 1, further comprising operating the hybrid vehicle in a third drive state in which the drive is in a traction mode of operation and a recuperation intensity stage of the electric motor is lowered.

6. The method for operating a hybrid vehicle according to claim 1, further comprising varying the time threshold value as a function of the speed of the hybrid vehicle.

7. The method for operating a hybrid vehicle according to claim 1, wherein the determination of the presence of the condition comprises: determining an intensity of the actuation of the operating element, comparing the intensity to an intensity threshold value, and determining whether the intensity is above the intensity threshold value.

8. The method for operating a hybrid vehicle according to claim 7, further comprising varying the intensity threshold value as a function of the speed of the hybrid vehicle.

9. A hybrid vehicle comprising: a drive comprising an internal combustion engine; an energy converter comprising an electric machine that can be operated for recuperation purposes; a control unit comprising a computing unit and a memory unit; and an operating element; wherein the memory unit stores a program configured to: glide the hybrid vehicle when the drive is not in a propulsion mode of operation and when an electric motor is operated in a recuperation intensity stage in a first drive state, determine an actuation of the operating element, determine whether a condition is present based on the actuation by determining a duration of the actuation of the operation element, comparing the duration to a time threshold value and determining whether the duration is below the time threshold value, and if the condition is present, change over from the first drive state to a second drive state, and operate the hybrid vehicle in the second drive state.

10. The hybrid vehicle according to claim 9, wherein the operating element is a pedal, a selector lever, a manual switch, or a touch panel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 is a sequence diagram of a preferred embodiment of the method according to the invention,

[0032] FIGS. 2A and 2B are diagrams in two partial drawings to illustrate the changeover from the first drive state to the second drive state as a functionaccording to the inventionof a time threshold value or of an intensity threshold value, and

[0033] FIG. 3 is a schematic view of the topology of a hybrid vehicle according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0034] FIG. 1 is a sequence diagram of a preferred embodiment of the method according to the invention for operating a hybrid vehicle. The hybrid vehicle has a topology of the type described below, taking into consideration the schematic view of Figure below 3, and it has a programmed or programmable control unit that can execute the method sequence. Preferably, it is a micro hybrid vehicle.

[0035] Initially, the hybrid vehicle according to the invention is operated in a first drive state (Step 10). In this first drive state, the hybrid vehicle glides when the drive is not in the propulsion mode of operation, in the free-wheeling mode with the drive switched off, and without an operated recuperative electric motor, in other words, at a recuperation intensity stage of zero. In Step 12, an actuation of the operating elementin this preferred embodiment an actuation of the brake pedalis determined by the control unit of the hybrid vehicle. This determination is initially qualitative and it constitutes a starting condition for the quantitative evaluation of the nature of the actuation. Then, in the control unit of the hybrid vehicle, the determination is made on the basis of the actuation as to whether a prescribed condition has been fulfilled (Step 14). Step 16 comprises individual sub-steps or sub-sequences. It is determined how long the brake pedal has been actuated (Sub-step 16). The determined time duration is compared to a time threshold value (Sub-step 18). Then the determination is made as to whetherthat is to say thatthe duration is below the time threshold value (Sub-step 20). The determination can entail that a variable in the control unit is set to a value that characterizes the fact that the magnitude has fallen below the time threshold value. If it is determined in the control unit that the condition is present, then the first drive state is changed over to the second drive state (Step 22). The hybrid vehicle is then operated in the second drive state, whereby the drive is switched on and then the drive is used in the propulsion mode of operation.

[0036] FIG. 2 shows diagrams in two partial drawings FIGS. 2A and 2B to illustrate the changeover from the first drive state to the second drive state as a functionaccording to the inventionof a time threshold value or of an intensity threshold value.

[0037] The partial drawing FIG. 2A groups two diagrams. As a function of the time 24, whose course should not be viewed quantitatively but rather only by way of an example, the actuation 26 of the operating element is plotted qualitatively in the upper diagram of the partial drawing FIG. 2A. If an actuation is present, a value that is not equal to zero is depicted in the diagram. The drive states are plotted qualitatively in the lower diagram of the partial drawing FIG. 2A. The first drive state 28 is depicted at a high level, and the second drive state 30 is depicted at a low level along the axis. Over the course of the time 24, a first changeover is made from the second drive state 30 to the first drive state 28 in the left-hand area of the partial drawing FIG. 2A. During operation in the first drive state, an actuation 26 of the operating element takes place for a short duration 32. According to the invention, the short duration 32 is evaluated and it is shorter than the time threshold value. Then the first drive state 28 is changed over to the second drive state 30. Over the further course of the time 24, a second changeover is made from the second drive state 30 to the first drive state 28 in the right-hand area of the partial drawing FIG. 2A. During operation in the first drive state, an actuation 26 of the operating element takes place for a long duration 34. According to the invention, the long duration 34 is evaluated and it is longer than the time threshold value. The hybrid vehicle remains in the first drive state 28. No changeover is made to the second drive state 30.

[0038] The partial drawing FIG. 2B likewise groups two diagrams. As a function of the time 24, whose course cannot be seen quantitatively but rather only by way of an example, the intensity 36 of the actuation of the operating element is plotted quantitatively with the appropriate unit in the upper diagram of the partial drawing FIG. 2B. An intensity threshold value 38 is drawn in the diagram. As explained above, the intensity threshold value 38 is a function of the speed of the hybrid vehicle. The drive state is plotted qualitatively in the lower diagram of the partial drawing FIG. 2B. The first drive state 28 is shown at a high level, and the second drive state 30 is shown at a low level along the axis. Over the course of the time 24, a changeover is made from the second drive state 30 to the first drive state 28. During operation in the first drive state 28, over the course of the time 24, a first, weak actuation 40 of the operating element, which does not exceed the intensity threshold value 38, takes place. According to the invention, the hybrid vehicle remains in the first drive state 28. Over the further course of the time 24, a sufficiently intense actuation 42 of the operating element takes place. The intensity 36 reaches the intensity threshold value 38 at a point in time 44. According to the invention, as a consequence, a changeover is made from the first drive state 28 to the second drive state 30, and the hybrid vehicle is then operated further in the second drive state 30. In this manner, correction braking operations are made possible according to the invention, without leaving the first drive state 28.

[0039] FIG. 3 schematically shows the topology of a hybrid vehicle 46 according to the invention, preferably a micro hybrid vehicle. The hybrid vehicle 46 has a drive 48 comprising an internal combustion engine 50 and an energy converter 52 with an electric motor. In the case of micro hybrid vehicles, the energy converter 52 with the electric motor is a starter-generator. The electric motor can be operated for purposes of recuperation or for recovering energy in electric form. Moreover, the hybrid vehicle has a control unit 54 that is operatively connecteda signal connectionto an operating element 56, here preferably the brake pedal of the hybrid vehicle, and to the drive 48. In the preferred topology shown in FIG. 3, especially the micro hybrid vehicle, the energy converter 52 is part of the drive 48, so that the control unit 54 that is operatively connected to the drive is also operatively connected to the energy converter 52. The control unit 54 comprises a computing unit 58 and a memory unit 60. According to the invention, a program is stored in the memory unit 60. The program can be part of the motor control program. When at least parts of the program are executed in the computing unit 58, a method, as elucidated above with reference to FIG. 1, is carried out.

LIST OF REFERENCE NUMERALS

[0040] 10 operation in the first drive state

[0041] 12 actuation of an operating element

[0042] 14 determination of a condition

[0043] 16 determination of a duration

[0044] 18 comparison to a time threshold value

[0045] 20 determination of the condition

[0046] 22 changeover to and operation in the second drive state

[0047] 24 time

[0048] 26 actuation of the operating element

[0049] 28 first drive state

[0050] 30 second drive state

[0051] 32 short duration

[0052] 34 long duration

[0053] 36 intensity

[0054] 38 intensity threshold value

[0055] 40 weak actuation

[0056] 42 sufficiently strong actuation

[0057] 44 point in time when the intensity threshold value is reached

[0058] 46 hybrid vehicle

[0059] 48 drive

[0060] 50 internal combustion engine

[0061] 52 energy converter

[0062] 54 control unit

[0063] 56 operating element

[0064] 58 computing unit

[0065] 60 memory unit