Method for operating drive train

The Invention relates to a method for operating a drive train of a motor vehicle according to the preamble of claim 1 and 7 respectively.

On Powertrain of a hybrid vehicle includes, in addition to a hybrid drive a transmission, wherein the hybrid drive an internal combustion engine, a includes an electric motor and an electric energy storage. at purely electromotive drive with engine off is the motor vehicle solely by the electric motor using the data stored in the electric energy storage energy driven. In a hybrid drive is such a vehicle: driven by the electric motor and internal combustion engine. In so-called Recuperation of the electric motor is operated as a generator, to charge the electric energy storage. Instead of an electric motor and an electrical energy storage device can also be a kinetic Memory or a pressure accumulator, with a corresponding motor is provided, be.

Around the drive train of a hybrid vehicle, taking into account the consumption of the engine as well as taking into account the Efficiency of the electric motor and the electric energy store optimally operate, the selection is made for an operational mode the drive train, on the basis of which the electrical energy store discharged, charged or on an unchanged charge level is maintained, depending on a desired charge level, and an actual state of charge of the electric energy storage device. The actual state of charge the electrical energy accumulator can be detected by measurement. The desired state of charge has the same determined in another way will.

Out of the <patcit><text>EP 211 121 B1 1</text></patcit> is it is known, the charging and discharging of the electric energy storage device and thus the determination of a setpoint state of charge of the same from pending to design data of a navigation device, the navigation device Driving information of distance to be traveled by the vehicle Distance and height corresponding information contains. After <patcit><text>EP 1211121 B1</text></patcit> is accordingly the determination of an operational mode for the drive train, on the basis of which the electrical energy store is the hybrid drive is loaded or unloaded, foresighted based Route data of the vehicle from a navigation device to be provided. This is costly.

Of this the object of the present invention based on the object a novel method for operating a drive train of a motor vehicle to accomplish.

After a first aspect of the invention, this object by a method achieved in accordance with Patent Claim first After this first aspect of the invention, the target state of charge of the electric Energy storage depending on a current driving condition the motor vehicle is determined such that depending on a instantaneous speed of the motor vehicle and / or depending on current transmission data and / or dependent on current Hydridantriebdaten an imminent delay or an imminent acceleration or an upcoming constant travel the motor vehicle is closed and in response thereto the Target state of charge of the electrical energy accumulator is determined.

After a second aspect of the invention, this object is through a A method according to claim resolved. 7 According to the second aspect of the invention, either alone or are used in combination with the first aspect of the invention may be range limits and / or the range limits defined range extensions of operating modes depending shifted from the desired charge state.

The Inventive process permits a simple and efficiency-optimized charging of the electrical energy accumulator a motor vehicle with a hybrid drive. There are no forward-looking Data, such as. For example, data of a navigation device, it is necessary to the drivetrain within the meaning of the present invention, operate. There are own data about the current driving condition of the motor vehicle for operating the drive train of the same required.

Preferred Further developments of the invention result from the dependent claims and the following description. Embodiments of be invention, but are not limited to, reference to the drawing explained. In which:

<figref idrefs="S13">1</figref> a highly schematic view of a powertrain, in which the The process according to the invention can be used; and

<figref idrefs="S13">2</figref> on Diagram to illustrate the present invention Process.

<figref idrefs="S13">1</figref> shows highly schematically a motor vehicle, the drive train a Hybrid drive with an internal combustion engine <figref>10</figref>, An electric motor <figref>11</figref> and an electrical energy storage <figref>12</figref> includes. additionally includes the drive train of the motor vehicle of <figref idrefs="S13">1</figref> on gear <figref>13</figref>, Of course, more can Electric motors or machines be provided.

At the gear <figref>13</figref> it is preferably an automatic transmission, are in which gear shift automated or performed automatically.

in the electrical energy storage <figref>12</figref> of the drive train of the Motor vehicle in accordance <figref idrefs="S13">1</figref> is electric Energy stored by the electric motor <figref>11</figref> be used can to the motor vehicle with a purely electric motor drive exclusively through the electric motor <figref>11</figref> or in a hybrid drive to support the internal combustion engine <figref>10</figref> with the aid of the electric motor <figref>11</figref> to drive.

in the Recuperation, the electric motor <figref>11</figref> as a generator are operated to the electric energy storage <figref>12</figref> to load.

Of the State of charge of the electric energy storage device <figref>12</figref> will also be called SOC (State of Charge).

Around optimized efficiency of the drive train of such a hybrid vehicle, To operate, an actual state of charge of the electric energy storage device <figref>12</figref> and a target state of charge determined thereof, wherein, depending the actual charge state and target state of charge of the electrical energy accumulator <figref>12</figref> on Operating mode for the drive train is determined, and wherein the electrical energy store <figref>12</figref> dependent either unloaded from certain mode or loaded or a constant state of charge is maintained.

Of the Actual state of charge of the electric energy storage device <figref>12</figref> can be easily determined on metrological way either directly or by using a model-based approach.

in the Sense of the present invention, the target state of charge the electrical energy store <figref>12</figref> dependent determined by a current driving state of the motor vehicle. For this purpose, no predictive data z. B. a navigation device required.

Of the Target state of charge of the electrical energy accumulator <figref>12</figref> becomes thereby determined such that depending on a current Speed ​​of the motor vehicle and / or depending on current transmission data and / or dependent on current hybrid drive data an imminent delay or an imminent Acceleration or an upcoming constant travel of the motor vehicle closed and in response thereto, the target state of charge of the electrical energy accumulator is determined. Depending on this target state of charge of the electrical energy accumulator <figref>12</figref> and the metrologically determined actual state of charge of the electric energy storage device <figref>12</figref> becomes one of several operating modes for the drive train determined, which then serves the operation of the powertrain. dependent thereof then the electric energy storage <figref>12</figref> unloaded or charged or held at a constant state of charge.

The Determining the desired state of charge of the electric energy storage device <figref>12</figref> and thereof depending on the determination of an operational mode for the driveline is accordingly using instantaneous driving state data powertrain without future or forward-looking accessed data, such as. for example, data of a navigation device, must become.

Out the current transmission data and / or the current hybrid drive data the powertrain is a current inclination of the motor vehicle intended to function thereof the desired state of charge of the electrical energy accumulator <figref>12</figref> to determine. The current Inclination of the motor vehicle can consist of a current transmission output speed the transmission <figref>13</figref>, From the current gear ratio the transmission <figref>13</figref>, From the provided by the hybrid drive Transmission input torque and from the acceleration of the motor vehicle be determined. For example, the longitudinal acceleration of the motor vehicle on the wheel or in electrical Drive of the hybrid vehicle from the rotational speed of the electric machine certainly. Since the measured acceleration by an acceleration sensor additionally contains the slope component can a corresponding slope are then derived geometrically, via the forces acting on an inclined plane forces.

Then, if determined to be current inclination of the motor vehicle a pitch is, can an imminent acceleration phase of the motor vehicle getting closed. Even at a constant rate of Motor vehicle has the hybrid drive a greater transmission input torque to be provided.

Then however, if a slope is determined as a tendency can an imminent deceleration phase of the motor vehicle getting closed. The delay can, for example, by actuation of the brake pedal, or as a constant velocity are in recuperation realized.

dependent thereof is then the desired state of charge of the electric energy storage device <figref>12</figref> certainly, to z. B. at a forthcoming deceleration phase of Motor vehicle Rekuperationspotentiale for charging the electric energy storage <figref>12</figref> To exploit.

Then, when the detected in the above manner target state of charge the electrical energy store <figref>12</figref> smaller than the actual state of charge is the same, is for discharging the electric energy store <figref>12</figref> on Operating mode for the drive train determines the a Load point shift for the engine <figref>10</figref> in Towards a lowering of the load point causes. Then, however, when the setpoint state of charge of the electric energy storage device <figref>12</figref> greater as the actual state of charge thereof, is for charging the electric energy storage <figref>12</figref> an operation mode of the drive train determines a load point shift for the engine <figref>10</figref> in Towards lifting the load point causes thereof.

With Help the procedure for determining the desired power level of the above-described energy storage <figref>12</figref> a hybrid powertrain, a simple control for the target state of charge of the electric energy storage <figref>12</figref> be established, alone on the basis of data concerning the current driving state of the motor vehicle without on forward-looking data such. B. Data a navigation device to be accessed. It is hereby an efficiency-optimized charging of the electrical energy accumulator <figref>12</figref> possible. Depending on the above-described determination of the desired state of charge for the electric energy storage <figref>12</figref> and dependent the selected mode is a load point of the internal combustion engine <figref>10</figref> shifted.

<figref idrefs="S13">2</figref> shows a diagram showing a further aspect of here present invention, wherein according to this further aspect of here the present invention limits the range and / or range limits defined range extensions of operating modes for the Powertrain be shifted depending on the desired state of charge.

So shows <figref idrefs="S13">2</figref> two charts, with horizontally extending on the Axis of the two diagrams respectively the state of charge of the electric energy storage device is plotted in percent.

about this state of charge of the electrical energy accumulator <figref>12</figref> are In the illustrated embodiment, a total of seven operating modes distributed, namely the operating modes <figref>14</figref>. <figref>15</figref>. <figref>16</figref>. <figref>17</figref>. <figref>18</figref>. <figref>19</figref> and <figref>20</figref>. wherein in the operation modes <figref>14</figref>. <figref>15</figref> and <figref>16</figref> on Discharging the electrical energy store <figref>12</figref> , whereby in the operation modes <figref>18</figref>. <figref>19</figref> and <figref>20</figref> on Charge the electrical energy storage device <figref>12</figref> takes place, and wherein in the operating mode <figref>17</figref> without charging or discharging the electrical energy store <figref>12</figref> the electric motor <figref>11</figref> of Hybrid drive just created so much energy that a so-called is covered board power requirement of the drive train. The operating modes<figref>14</figref>. <figref>15</figref> and <figref>16</figref> to the Discharging the electrical energy store <figref>12</figref> and operating modes <figref>18</figref>. <figref>19</figref> and <figref>20</figref> for charging the electrical energy store <figref>12</figref> differ regarding their Entladeintensität or Aufladeintensität, said Aufladeintensität the operating mode <figref>20</figref> greater is defined as the operating mode of the Aufladeintensität <figref>19</figref>. and the Aufladeintensität the operating mode <figref>19</figref> greater is defined as the operating mode of the Aufladeintensität <figref>18</figref>, The Entladeintensität the operating mode <figref>15</figref> is greater than that of the Entladeintensität operation mode <figref>14</figref>, Further, the Entladeintensität the operating mode <figref>14</figref> greater than the Entladeintensität the operating mode <figref>16</figref>,

in the in <figref idrefs="S13">2</figref> shown embodiment for shifting of range limits and / or range extensions of the operating modes <figref>14</figref>. <figref>15</figref>. <figref>16</figref>. <figref>17</figref>. <figref>18</figref>. <figref>19</figref> and <figref>20</figref> becomes so doing that the area extent of the operation modes <figref>14</figref>. <figref>15</figref>. <figref>17</figref>. <figref>19</figref> and <figref>20</figref> always remains unchanged, however, that depending on the determined Target state of charge SOC_SHOULD of electrical energy storage <figref>12</figref> the range limits of the operating mode <figref>17</figref> so be moved, that the target state of charge SOC_SHOULD always within the range extension of the operating mode <figref>17</figref> lies, z. B. in the middle, in which the electric motor <figref>11</figref> of Hybrid drive without charging or discharging the electrical energy store <figref>12</figref> just much energy is generated that a board power requirement of the drive train is covered. Depending on this shift of the range limits the operating mode <figref>17</figref>Whose range extension in the embodiment shown always unchanged 10% state of charge of the energy store <figref>12</figref> is, shifts the lower limit of the operating mode <figref>16</figref> and the upper limit of the operating mode <figref>18</figref>Whereas the upper limit of the operating mode <figref>16</figref> and lower Range limit of the operating mode <figref>18</figref> remains unchanged. It follows that the area extent of the operation modes <figref>16</figref> and <figref>18</figref> dependent the determined nominal state of charge SOC_SHOULD changed.

In the two diagrams of <figref idrefs="S13">2</figref> additionally the target state of charge SOC_SHOULD_. on Based on which area boundaries and / or range extensions be moved by operating modes, also detected by measurement If state of charge SOC_IS registered with In the left diagram of <figref idrefs="S13">2</figref> the setpoint state of charge of the electric energy storage <figref>12</figref> greater than the actual state of charge is the same, it follows that for the left diagram of the <figref idrefs="S13">2</figref> as Operating mode for the drive train of the operating mode <figref>18</figref> chosen is, to the electric energy storage <figref>12</figref> load and so the actual state of charge to the target state of charge to approximate the same.

For the right diagram of <figref idrefs="S13">2</figref>, In welChem the target state of charge the electrical energy store <figref>12</figref> smaller than the actual state of charge is the same, is the operating mode for the drive train the operating mode <figref>16</figref> chosen as the energy storage <figref>12</figref> to discharged and the actual charging state of the same to the target state of charge to approach.

in the In contrast to the <figref idrefs="S13">2</figref> illustrated embodiment it is possible for the operating mode <figref>17</figref> not only the range boundaries but also the range extension depends adjust the determined target boost state. can also for the operating modes <figref>14</figref>. <figref>15</figref>. <figref>19</figref> and <figref>20</figref> range limits Area extents are adjusted the same and / or.

transitions between the individual operating modes <figref>14</figref> to <figref>20</figref> to the Operating the powertrain done discretely.

QUOTES INCLUDED IN THE DESCRIPTION

This list the documents cited by the applicant has been automated created and is exclusively to inform the reader's convenience. The list is not part of the German Patent or utility model application. The DPMA takes no liability for errors or omissions.

Cited patent literature

<ul><li>- EP 1211121 B1 <b>[0004, 0004]</b></li></ul>