EP2704936A1

EP2704936A1 - Method for operating a drive train of a hybrid vehicle

Info

Publication number: EP2704936A1
Application number: EP12710915.5A
Authority: EP
Inventors: Markus Eisele; Yvonne WIEGANG; Bert Hellwig
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2011-05-03
Filing date: 2012-03-20
Publication date: 2014-03-12
Also published as: DE102011075145A1; WO2012150088A1

Abstract

The invention relates to a method for operating a drive train of a hybrid vehicle, said drive train having a drive unit (1) that comprises an electric machine (3) and an internal combustion engine (2), and having an electric energy store (7) which is discharged to a greater degree when the electric machine is operated as a motor, and charged to a greater degree when the electric machine is operated as a generator. At the output end (4), an output torque is provided depending on a selected operating mode, namely exclusively by means of the electric machine (3) when in an electric operating mode or by means of both the electric machine and the internal combustion engine (2) when in a hybrid operating mode, while complying with a state-of-charge operating range of the electric energy store (7). Triggered by a driver-side actuation of a control element, a hybrid preparatory operating mode, in which the electric energy store has an extended state-of-charge operating range, is activated automatically to prepare an electric operating mode or hybrid operating mode that follows a defined travelled trip route or trip duration in response to the driver-side actuation of the control element. In said preparatory operating mode, the electric machine and internal combustion engine are operated such that, after the defined trip route or duration, the state-of-charge of the electric energy store (7) corresponds to an extended threshold value of the extended state-of-charge operating range.

Description

A method of operating a powertrain of a hybrid vehicle

The invention relates to a method for operating a drive train of a hybrid vehicle according to the preamble of claim 1. Furthermore, the invention relates to a control device for carrying out the method.

Hybrid vehicles, the drive unit comprising an electric machine and an internal combustion engine, are well known in practice. Thus, hybrid vehicles can be operated purely electrically in an electric operating mode, in which case only the electric machine of the hybrid vehicle at an output of the same provides an output torque. Furthermore, hybrid vehicles can be operated in a hybrid mode of operation, in which case both the electric machine and the internal combustion engine of the hybrid vehicle at the output provides an output torque. The electric machine of such a hybrid vehicle can be operated on the one hand by a motor and on the other hand by a generator, wherein in the motor operation of the electric machine the same one more discharges an electrical energy store of the hybrid vehicle and charges it more in regenerative operation.

From practice, it is also already known to predictively determine an operating mode for the hybrid vehicle on the basis of topographical data of a driving distance ahead of the hybrid vehicle. This topographical data of the route lying in front of the hybrid vehicle is provided by a navigation system or a GPS system in hybrid vehicles known from practice. Alternatively, it is also known for hybrid vehicles such. B. for city buses, which are operated on recurring routes to measure the routes in advance by departing the same and maintain appropriate route data in a memory. Both the provision of the topographical route data via a GPS system or navigation system and the pre-measurement by driving off the routes and storage of the route data requires a high device complexity and application costs. There is therefore a need for a method for operating a drive train of a hybrid vehicle and at a control device for carrying out such a method, with which without the need for a GPS system or navigation system and without the need for pre-measurement of the route by departing the same a suitable operating mode for a hybrid vehicle with optimization of the efficiency of the hybrid vehicle can be selected.

On this basis, the present invention based on the object to provide a novel method for operating a drive train of a hybrid vehicle and a control device for carrying out the method.

This object is achieved by a method according to claim 1. According to the invention, a hybrid preparation operating mode with an extended permissible charge state operating range of the electrical energy store is automatically activated by a driver-side actuation of an operating element in preparation for an electric operation mode or hybrid operating mode related to the driver-side actuation of the operating element after a defined travel distance or driving time, wherein in the hybrid preparation operating mode the electric machine and the internal combustion engine are operated automatically such that, after the defined travel distance or travel time, the charge state of the electrical energy store automatically corresponds to an extended limit value of the extended permissible charge state operating range.

The method according to the invention runs automatically after a driver-side release by actuation of a control element.

For performing the method no topographic route data is needed. The hybrid vehicle according to the invention thus comes without GPS system and navigation system. Furthermore, it is not necessary to pre-measure a route by departing the same and to save corresponding route data. Rather, after the driver-side actuation, a hybrid preparation mode of operation is automatically activated and selected for the operation of the hybrid vehicle, with the hybrid preparation mode of operation providing an extended allowable state of charge operating range for the electrical energy storage over the previous hybrid mode or electric mode.

During the hybrid preparation mode of operation, the powertrain is automatically operated such that after the defined cruise distance or drive duration after activation of the hybrid preparation mode, the state of charge of the electrical energy store automatically corresponds to an extended, upper or extended lower limit of the extended, allowable state of charge operating range of the electrical energy store.

As a result, the hybrid vehicle can be adapted or prepared for an electric operating mode or subsequent hybrid operating mode following the hybrid preparation operating mode without knowledge of topographical travel route data.

According to an advantageous development, when the hybrid preparatory operating mode is activated, a charging state of the electrical energy store that forms is automatically monitored in such a way that if a defined travel distance or time interval is detected before the defined travel distance or travel time expires, the charge state of the electrical energy store is the upper limit value has not yet reached or will not reach the extended allowable state of charge operating range, a load point boost is automatically made to the internal combustion engine. This development of the invention is particularly suitable for adapting or preparing the hybrid vehicle to an electric operating mode for a zero emission travel path following the hybrid preparation operating mode or to a subsequent hybrid operating mode for uphill driving or for a subsequent hybrid operating mode with power takeoff activation. According to a further advantageous development, when the hybrid preparatory operating mode is activated, a charging state of the electrical energy store that forms is automatically monitored such that when a defined travel distance or time interval is detected before the defined travel distance or travel time expires, the charge state of the electrical energy store is extended Lower limit of the extended allowable state of charge operating range has not yet reached or will not reach automatically a load point reduction is made for the internal combustion engine. This development of the invention is particularly suitable for adapting the hybrid vehicle to an electric operating mode or hybrid operating mode for a downhill following the hybrid preparation operating mode.

Preferably, the defined driving distance or driving time of the hybrid preparation operating mode is automatically determined when the operator controls the driving element, with a constant driving distance or driving time or a variable driving distance or driving time depending on an operating time or operating frequency of the operating element being used as the defined driving distance or driving time of the hybrid preparation operating mode. The above determination of the defined travel distance or travel time of the hybrid preparation operating mode, within which the electrical state of charge of the electrical energy store is to adopt the extended limit value of the extended state of charge operating range, is particularly simple and preferred.

The control device according to the invention has means for carrying out the method according to the invention.

Preferred embodiments of the invention will become apparent from the dependent claims and the description below. Embodiments of the invention will be described, without being limited thereto, with reference to the drawings. Showing:

Fig. 1 is an exemplary diagram of a hybrid vehicle; 2 shows a diagram to illustrate the method according to the invention for operating a drive train of a hybrid vehicle.

The present invention relates to a method for operating a drive train of a hybrid vehicle and to a control device for carrying out the method.

FIG. 1 shows in highly schematized form a drive train diagram of a hybrid vehicle with a drive unit 1, which comprises an internal combustion engine 2 and an electric machine 3. Between the drive unit 1 and an output 4 of the hybrid vehicle, a transmission 5 is connected, which is preferably designed as an automatic or automated manual transmission. Between the engine 2 and the electric machine 3 of the drive unit 1, a clutch 6 is connected. When the clutch 6 is open, the internal combustion engine 2 is decoupled from the output 4, in which case the internal combustion engine 2 is stopped when the clutch 6 is open and the drive train can be driven purely electrically in an electric mode starting from the electric machine 3. For a hybrid operating mode, the clutch 6 is closed, in which case the internal combustion engine 2 runs in the hybrid operating mode and is coupled to the output 4 through the closed clutch 6. The electric machine 3 of the drive unit 1 is associated with an electrical energy storage 7. The electric energy storage 7 is in the motor operation of the electric machine 3 of the same more dischargeable and in regenerative operation of the electric machine 3 of the same more rechargeable. In this case, a permissible charge state operating range of the electrical energy store 7, which is defined by an upper limit value and a lower limit value, is observed.

The operation of the internal combustion engine 1 is controlled or regulated in the drive train of FIG. 1 by a motor control device 8. For controlling or regulating the operation of the transmission 5, the drive train comprises a transmission control device 9. A hybrid control device 10 controls the operation of the electric machine 3. For controlling or regulating the components 1, 3 and 5 via the control devices 8, 9 and 10, the control devices 8, 9 and 10 exchange data with the components 2, 3 and 5 in the sense of the double arrows, the control device 8, 9 and 10 exchange data with each other.

It should be noted at this point that the hybrid control device 10 may also be part of the transmission control device 9 or the engine control device 8.

According to the invention it is proposed that, triggered by a driver-side actuation of a control element 1 1 of the drive train of the hybrid vehicle automatically a hybrid preparation operating mode for the operation of the drive train in preparation for a related to the driver-side actuation of the control element 1 1 after a defined route or driving time subsequent electric mode or hybrid mode is activated.

This hybrid preparation mode of operation is characterized by an extension of the allowable state of charge operating range of the electric energy storage. To extend the allowable state of charge operating range, an upper limit of the state of charge operation range is shifted upward or a lower limit of the state of charge operation range downward, respectively.

In the hybrid preparation operating mode, the electric machine 3 and the internal combustion engine 2 of the drive unit 1 are then automatically operated in such a way that the charge state of the electrical energy store 7 automatically corresponds to an extended limit value of the extended, permissible charge state operating range of the electrical energy store 7 after the defined travel distance or journey time of the hybrid preparation operating mode that is, either the upper limit shifted up or the lower limit of the state of charge operating range shifted down. The method according to the invention accordingly prepares a drive train, in particular the state of charge of an electrical energy accumulator 7 of the drive train, triggered by a driver-side actuation of the operating element 11 fully automatic on a subsequent electric operating mode or hybrid operating mode, namely such that with termination of the hybrid preparation operating mode and thus with the beginning of the subsequent electrical operating mode or hybrid mode of operation, the state of charge of the electrical energy storage 7 corresponds to a limit of the extended, permissible state of charge operating range of the electrical energy store 7 extended or shifted for the hybrid preparation operating mode.

The invention will be described below with reference to FIG. 2 in the case where the powertrain of a hybrid vehicle is to be automatically prepared for an electric emission mode for a zero emission travel ahead of the hybrid vehicle. For this purpose, in Fig. 2, in which over the time t o- over a distance s the state of charge SOC of the electrical energy store 7 is plotted, at a time tO or at a distance sO by driver-side actuation of the control element 1 1 automatically the hybrid Preparing mode activated and this automatically raised an upper limit SOC-MAX of the permissible state of charge operating range of the electric energy storage device 7 to the extended upper limit SOC-MAX-E. Subsequent to this driver-side actuation of the operating element 11 and the automatic activation of the hybrid preparation operating mode effected thereby, the internal combustion engine 2 and the electric machine 3 are operated automatically in particular in a controlled manner by the hybrid control device 10 which serves to carry out the method according to the invention in that, based on the driver-side actuation of the operating element 11 at the time t0 or the distance sO after a defined travel time At1 or after a defined driving distance As1, the state of charge SOC of the electrical energy store 7 automatically follows the extended, upper limit value SOC-MAX. E of the extended, permissible state of charge operating range of the electrical energy store 7 corresponds. Depending on the unknown topographical route profile during the route As1 or travel time At1 of the preparatory mode of operation, a chronological course or route-dependent course of the state of charge SOC is formed starting from an initial value SOC-0 of the state of charge at the time t0 or the distance sO, namely, at the end of the preparatory operating mode, when the travel time At1 has elapsed or when the driving distance As1 has been completed, the raised, upper limit value SOC-MAX-E of the extended, permissible charge state operating range of the electrical energy store 7 has been reached.

When activated hybrid preparation operating mode, ie during the route As1 or the travel time At1, the developing state of charge SOC of the electrical energy storage device 7 is monitored automatically such that when it is detected that a defined path distance As2 or a defined time interval At2 before the defined driving distance As1 or the defined travel time At1 the charge state SOC of the electric energy store 7 has not yet reached or will not reach the extended, upper limit value of the extended, permissible charge state operating range, a load point increase for the internal combustion engine 2 is automatically carried out, so that the Charging state SOC of the electric energy storage device 7 reaches the upwardly extended or raised limit value SOC-MAX-E after expiry of the defined travel distance As1 or the defined travel time At1 with the assistance of the internal combustion engine.

With the expiry of the journey time At1 or reaching the route As1 after automatic activation of the hybrid preparation operating mode, the previously raised or extended upper limit of the permissible state of charge operating range is again reduced during the subsequent change to the prepared electrical operating mode for the zero emission travel distance and preferably based on this operating mode change, the 2 at the time t1 or to the driving position s1, the lower limit value of the permissible state of charge operating range is lowered for a defined travel distance or travel duration in order to ensure purely electrical operation of the hybrid vehicle via the electric machine 3 during the entire electric operating mode of the zero emission travel path to ensure electrical energy storage 7. The defined travel distance As1 or travel time At1 of the hybrid preparation operating mode is automatically determined by the driver implementing the method control device, in the embodiment shown by the hybrid control device 10 at driver side actuation of the control element.

It can be provided that a constant travel distance or driving time is used and selected as defined travel distance As1 or travel time At1 of the hybrid preparation operating mode, which is constant for each actuation of the corresponding operating element 11.

Alternatively, it may be provided to use a variable travel distance As1 or travel duration At1 that is dependent on an actuation duration or actuation frequency of the operating element 1 1 as the defined travel distance As1 or travel time At1 of the hybrid preparation operating mode. Thus, it can be provided that for each actuation of the operating element 1 1 an increment for the defined travel distance As1 or travel time At1 of the hybrid preparation operating mode is stored in the hybrid control device 10. Thus, if the driver 1 1 operated only once, then a relatively short distance As1 or driving time At1 for the hybrid preparation mode is then automatically determined and used, whereas when the actuator 1 1 is pressed several times, a correspondingly longer travel distance As1 or journey time At1 the hybrid preparation mode of operation is determined and used.

For the hybrid preparation mode of operation for preparing the subsequent electric operation mode for a zero emission route, it can be provided, for example, that with simple actuation of the control element 1 1 as cruise As1 of the hybrid preparation mode of operation, a 200m route is used which, on double actuation of the control element, uses a route As1 of 400m is used that with triple actuation a distance As1 of 600m is used and that with n-times operation of the operating element a route As1 is used, which is nx200m. The method according to the invention is not limited to the preparation of an electric operating mode for a zero emission travel route. Rather, with the method according to the invention or the control device according to the invention, a hybrid operating mode for uphill driving or a hybrid operating mode with a power take-off activation, which is also referred to as PTO activation, can be carried out.

Thus, in the preparation of a preparatory operating mode for an upcoming uphill drive by means of the method and the control device according to the invention, it is possible to automatically activate the hybrid preparation mode after driver-side actuation of the control element 1 1 to move to the automatically determined, defined driving distance As1 or travel time At1 Operation of the control element 1 1 and prior to the start of the hybrid mode for driving uphill to increase the state of charge SOC of the electric energy storage device 7, namely on the way of activation of the hybrid preparation mode automatically raised upper limit SOC MAX-E of the state of charge operating range for the electrical energy storage. 7 In this case, the state of charge of the electrical energy store is then automatically raised accordingly during the preparatory mode of operation, so that for the subsequent uphill, in which we niger recuperation energy can be obtained, a sufficient state of charge of the electrical energy storage 7 is present. For all other details, reference may be made to the above-described procedure for preparing a zero mission route electrical operation mode.

An analogous procedure is possible for preparing a hybrid vehicle via the hybrid preparation operating mode, which is automatically activated after driver-side actuation of a control element 1 1, to a subsequent hybrid drive in hybrid operating mode with activated PTO or power take-off or activated PTO. In such a power take-off may be, for example, a cooling loader of a truck or other power take-off. Furthermore, it is possible with the method according to the invention to prepare a hybrid vehicle via the hybrid preparation operating mode to a subsequent electric operating mode or hybrid operating mode for downhill driving. In this context, then, after appropriate actuation of the control element 1 1 and thereby effected, automatic activation of the hybrid preparation operating mode of the permissible state of charge operating range is extended such that a lower limit thereof is shifted downwards and thus extended. Furthermore, in this context, the electric machine 3 and the internal combustion engine 2 are operated in such a way that, at the end of the defined driving distance or driving time of the hybrid preparation operating mode, the state of charge of the electrical energy store 7 adopts this lower limit value of the extended, permissible charge state operating range.

In this case, when the hybrid preparatory operating mode is activated, the state of charge of the electrical energy store 7 is preferably automatically monitored in such a way that, when it is determined that a defined travel distance or time interval before the expiration of a defined driving distance or driving time of the hybrid preparation operating mode, the state of charge is extended, lower Limit value has not yet reached or will not reach automatically a load point reduction is made for the internal combustion engine, so that the electrical energy storage 3 is discharged more strongly via the electric machine 3, so then the subsequent transition to the Elektrobetriebsmo- dus or hybrid mode for the downhill, the recuperation potential the mountain departure ahead of the hybrid vehicle can be fully exploited.

If appropriate, then for the subsequent downhill run, the upper limit of the state of charge operating range can be raised in order to fully exploit the recuperation potential.

In all embodiments of the invention, it is possible for the driver to visualize an activation of the hybrid preparation operating mode, which is automatically activated in the case of a driver-side actuation of the operating element 11, via a display device 12. Further, the driver may be notified of an imminent end of the hybrid preparation mode of operation via this indicator 12 so that the operator may adjust to an operating mode change from the preparatory mode to the subsequent electric mode or subsequent hybrid mode.

After activation of a hybrid preparation operating mode by corresponding driver-side actuation of the operating element 1 1 can further be provided in the sense of the invention that aborted by subsequent actuation of the control element 1 1 preparatory mode and returned to a regular electric mode or hybrid mode with respect to the extended state of charge limited operating state of charge state ,

It may be provided to provide a separate control element 1 1 for each electric operating mode or hybrid operating mode to be prepared. Furthermore, provision can be made for providing a common operating element 11 for operating modes to be prepared in the same direction in relation to the state of charge of the electrical energy store in the sense of greater charging or boosting of the electrical energy store.

The control device according to the invention is preferably a hybrid control device. The same has means for carrying out the method according to the invention, in particular interfaces for direct or indirect, unidirectional or bidirectional data exchange with the control element 1 1 and / or the electric machine 3 and / or the electric energy storage 7 and / or the internal combustion engine 2 and / or the Display device 12 and / or the coupling 6, as well as software and / or hardware-side means for evaluation and generation of corresponding, the implementation of the method serving data signals. An indirect data exchange takes place via interposition of another control device. The extended limit values for the extended charge state operating range of the electrical energy store in the preparation operating mode as well as the defined travel distances or driving times As1, At1, As2, At2 of the preparation operating mode and optionally increments for the defined travel distances or driving times As1, At1 of the preparation operating mode are preferably stored in a memory of the control device according to the invention and freely applicable via an interface.

REFERENCE CHARACTERS

power unit

internal combustion engine

electric machine

output

transmission

clutch

electrical energy storage

Motor controller

Transmission control device

Hybrid controller

operating element

display element

Claims

claims

1 . Method for operating a drive train of a hybrid vehicle, which comprises a drive unit (1) comprising an electric machine (3) and an internal combustion engine (2), a transmission (5) connected between the drive unit (1) and an output (4) and an electrical energy store (7), wherein the electrical energy store (7) in the engine operation of the electric machine (3) discharged more and more charged in regenerative operation of the electric machine (3), wherein the output (4) has an output torque depending on one for the Operation of the drive train selected operating mode in an electric operating mode exclusively via the electric machine (3) or in a hybrid operating mode both via the electric machine (3) and via the internal combustion engine (2) in each case while maintaining an allowable state of charge operating range of the electrical energy store (7) is provided, characterized in that au triggered by a driver-side actuation of a control element automatically a hybrid preparation operating mode with an extended allowable state of charge operating range of the electrical energy storage (7) is activated in preparation for a relation to the driver-side actuation of the control element after a defined distance or travel duration subsequent electric operating mode or hybrid operating mode, said in hybrid preparation operating mode, the electric machine (3) and the internal combustion engine (2) are operated so automatically that after the defined route or travel time, the state of charge of the electrical energy storage automatically corresponds to an extended limit of the extended state of charge operating range.

2. Method according to claim 1, characterized in that, when the hybrid preparation operating mode is activated, such a developing state of charge of the electrical energy store (7) is automatically monitored such that when a defined distance or time interval is detected before the defined travel distance or travel time expires, That the state of charge of the electric energy storage device (7) has not reached or will not reach an extended upper limit of the extended allowable state of charge operating range, a load point increase is automatically made for the internal combustion engine (2).

3. The method according to claim 2, wherein upon activation of the hybrid preparation operating mode, the upper limit of the permissible charge state operating range is automatically increased for expansion thereof, wherein the upper limit of the permissible charge state operating range is reduced again during the subsequent change to the now prepared electric operating mode or hybrid operating mode and based on this operating mode change, the lower limit value of the permissible charge state operating range is lowered for a defined travel distance or travel duration.

4. The method according to claim 2 or 3, characterized in that the hybrid preparation operating mode prepares a subsequent electric operation mode for a zero emission travel route or a hybrid operation mode for uphill driving or a hybrid operation mode with power take-off activation.

5. The method according to any one of claims 1 to 4, characterized in that when activated, hybrid preparation operating mode such a forming state of charge of the electrical energy storage device (7) is automatically monitored, that then, if a defined path distance or time interval before expiration of the defined route or Travel period is detected that the state of charge of the electric energy storage device (7) has not reached or will not reach an extended lower limit of the extended allowable state of charge operating range, a load point reduction for the internal combustion engine (2) is automatically made.

6. The method according to claim 5, characterized in that is prepared with the hybrid preparation operation mode, a subsequent electric operation mode or hybrid operation mode for a downhill.

7. The method according to any one of claims 1 to 6, characterized in that is automatically changed after expiry of the defined route or journey duration of the hybrid preparation operating mode in the now prepared electric operation mode or hybrid operation mode.

8. The method according to any one of claims 1 to 7, characterized in that the defined travel distance or travel time of the hybrid preparation operating mode is automatically determined when the driver side actuation of the control element.

9. The method according to any one of claim 8, characterized in that is used as a defined travel distance or travel time of the hybrid preparation operating mode, a constant driving distance or driving time.

10. The method according to any one of claim 8, characterized in that is used as a defined travel distance or travel time of the hybrid preparation operating mode, a variable, dependent on an operating time or frequency of operation of the control element driving distance or travel time.

1 1. Control device of a hybrid vehicle, in particular hybrid control device, characterized in that the same means for performing the method according to one of claims 1 to 10.