Method for controlling a hybrid drive for a vehicle and hybrid drive

Abstract

Method for controlling a hybrid drive (10) for a vehicle, wherein the hybrid drive (10) has an electric motor (12) for an electric motor drive of the vehicle, an internal combustion engine (14) for an internal combustion engine drive of the vehicle, a traction battery (26) for supplying energy to the electric motor (21), a charging connection for charging the traction battery (26) by an external power source, and a control unit for controlling the electric motor (12) and / or the internal combustion engine (14), in which the control unit (36) controls the electric motor (12) and / or the internal combustion engine (14) in an operating mode dependent on operating parameters, wherein a distance to a charging station is entered by a user via a first operating element (38) and transmitted to the control unit (36) as an operating parameter, and wherein the control unit (36) selects the operating mode such thatthat a probable charge state of the traction battery (26) reaches a predefined charge state after covering the entered distance, characterized in that a reserved electric range is entered by the user via a second control element (40) and transmitted to the control unit (36) as an operating parameter, and that the control unit (36) selects the operating mode such that the charge state of the traction battery (26) does not fall below a reserved charge state corresponding to the entered reserved electric range, wherein the currently selected operating mode is changed due to a changed weight of the vehicle, wherein the control unit (36) continuously monitors the currently selected operating mode at predefined time intervals or predefined distance intervals.

Description

The invention relates to a method for controlling a hybrid drive and a hybrid drive for a vehicle, wherein the hybrid drive has an electric motor for an electric motor drive of the vehicle, an internal combustion engine for an internal combustion engine drive of the vehicle, a traction battery for supplying energy to the electric motor, a charging connection for charging the traction battery by an external current source and a control unit for actuating the electric motor and / or the internal combustion engine, wherein the control unit actuates the electric motor and / or the internal combustion engine in an operating mode dependent on operating parameters, wherein a distance to a charging station is input by a user via a first operating element and is transmitted as an operating parameter to the control unit, and wherein the control unit selects the operating mode such that the expected state of charge of the traction battery reaches a predefined state of charge after the input distance has been travelled.The term hybrid drives refers to vehicle drives having more than one drive source. Hybrid drives, in particular, have gained great importance up to now, which consist of the combination of an internal combustion engine and at least one electric motor which is supplied with electrical energy from a traction battery carried in the vehicle, in particular motor vehicle. Different drive configurations of the hybrid drives can be differentiated depending on how the internal combustion engine and the at least one electric motor are arranged with respect to one another. The main distinguishing feature of the various configurations is serial, parallel or mixed. In the serial arrangement, the individual drive components are arranged in a row following one another. The vehicle is driven exclusively by means of the electric motor which is supplied with energy from the traction battery. The internal combustion engine serves to recharge the traction battery via a generator. In the parallel and the mixed arrangement, the vehicle is driven both by the at least one electric motor and by the internal combustion engine.A more detailed description of the various drive configurations can be found, for example, in the book "Bosch Kraftfahrrentechnische Taschenbuch", 25th edition 2003, Friedrich Vieweg & Sohn Verlag, Wiesbaden, pages 728 ff. The present invention relates in particular to the parallel and the mixed arrangement.In a hybrid drive with a parallel arrangement (so-called parallel hybrid), the internal combustion engine and the electric motor can be operated in different operating modes, such as, for example: 1) drive by internal combustion engine, 2) drive by electric motor, 3) drive by internal combustion engine and electric motor (so-called boost), 4) drive by internal combustion engine with charge of the traction battery, 5) regenerative brakes (so-called recuperation) and 6) charging of the traction battery when the vehicle is at standstill.In addition to the possibility of charging the traction battery by the internal combustion engine or the electric motor, concepts have also been developed for charging the traction battery via an external power source, for example during parking overnight via an external power grid. Vehicles with this possibility are called plug-in hybrid vehicles.US 2010 / 0 006 359 A1 discloses a method for controlling a hybrid drive for a vehicle, in which a user can enter, via a button, whether he wishes to drive home and charge his traction battery there. Depending on its decision, a state of charge for the traction battery is predefined at its destination.DE 10 2009 023 535 A1 discloses a vehicle having an electric drive, an electrical supply grid having at least one electrical load, an energy store, a human-machine interface, via which a minimum range of the vehicle to be achieved can be input by a user, and a device for regulating the charge content of the energy store, which is designed to make a remaining residual amount of charge available to the electrical supply grid.DE 10 2004 029 203 A1 discloses an operating device for a motor vehicle for changing continuously variable parameters, wherein the operating device comprises a touchscreen and the parameters can be changed by sweeping over an operating panel of the touchscreen.The object of the invention is to improve the operating strategy of the hybrid drive described at the beginning, in particular to reduce emissions which are harmful to the environment and to enable the user to operate in a flexible electric manner.This object is achieved according to the invention by a method of the generic type for controlling a hybrid drive in that a reserved electric range is input by the user via a second operating element and is transmitted as an operating parameter to the control unit, the control unit selects the operating mode such that the state of charge of the traction battery does not drop below a reserved state of charge which corresponds to the reserved electric range input, wherein the currently selected operating mode is changed on the basis of a changed weight of the vehicle, wherein the control unit continuously monitors the currently selected operating mode at predefined time intervals or predefined distance intervals.The control unit selects the operating mode in each case such that when the charging station, which represents an external power source, is reached, the usable charge content of the traction battery is utilized as far as possible, that is to say the vehicle is driven as far as possible with the electric motor. At the same time, the use of the internal combustion engine is limited to the most necessary. This results in a reduction of environmentally harmful emissions emitted from the internal combustion engine, for example CO2 emissionen.A reserve for electric driving desired by the user is achieved according to the invention in that a reserved electric range is input by the user via a second operating element and is transmitted to the control unit as an operating parameter, and in that the control unit selects the operating mode such that the state of charge of the traction battery does not drop below a reserved state of charge which corresponds to the reserved electric range input.Expediently, the control unit continuously monitors the currently selected operating mode. The monitoring takes place, for example, at predefined time intervals or predefined route intervals. During operation of the vehicle, it can namely be the result, due to different influencing factors, that a currently selected operating mode or an operating strategy determined for the route up to the charging station input, which may comprise a sequence of different operating modes, must be changed. Such influencing factors include, for example, a changed driving style of the driver (consumption increases or decreases in comparison to the assumed consumption), changed route on the basis of traffic messages, changed weight of the vehicle, changed settings of comfort consumers, defective traction battery, standstill in the traffic jam.Expediently, the predefined state of charge is set equal to the reserved state of charge if the predefined state of charge is less than the reserved state of charge. This makes it possible to ensure that the desired remaining range is available for electric driving even when the charging station is reached. Thus, the user can spontaneously stop the charging process and drive it electrically.User-friendly input of the distance to a charging station and / or of the reserved electrical range can be achieved if the first operating element and / or the second operating element is / are formed on a touchscreen. The input is particularly simple and intuitive if the first operating element and / or the second operating element is / are designed as a slider.This object is furthermore achieved according to the invention by a hybrid drive of the generic type in that a reserved electric range can be input by the user via a second operating element and can be transmitted to the control unit as an operating parameter, and in that the control unit is designed to select the operating mode such that the state of charge of the traction battery does not drop below a reserved state of charge which corresponds to the reserved electric range input, wherein the currently selected operating mode can be changed on the basis of a changed weight of the vehicle, wherein the control unit is designed to continuously monitor the currently selected operating mode at predefined time intervals or predefined route intervals.The features of the hybrid drive according to the invention correspond to the method according to the invention, so that reference is made to the above explanations.The drawing shows an exemplary embodiment of the invention. The following are shown: FIG. 1 is a block diagram of a hybrid drive according to the invention; and FIG. 2 shows a touchscreen with control elements and display contents.FIG. 1 shows a parallel hybrid drive 10 of a vehicle, which is not shown in detail.The vehicle is driven selectively or simultaneously by an electric motor 12 as a first drive source and an internal combustion engine 14 (Otto or Diesel engine) as a second drive source. Both power sources act directly or indirectly on a drive shaft 16 that drives a drive axle 18 of the vehicle. For example, the electric motor 12 may act on the crankshaft of the internal combustion engine 14, to which it may be connected in various ways. Thus, the electric motor 12 can be connected to the crankshaft via a clutch 22 or integrated into the vehicle transmission via a belt drive or a transmission or another switchable force- and / or form-fit connection, if the electric motor can be decoupled from the internal combustion engine by opening a form- or force-fit connection. The internal combustion engine 14 and the electric motor 12 are connected to the drive shaft 16 via a transmission 20. The transmission 20 can alternatively be designed as an automatic transmission or as a dual clutch transmission.FIG. 1 shows an additional clutch 24 which is arranged between internal combustion engine 14 and electric motor 12. Such an additional clutch 24 allows the internal combustion engine 14 to be decoupled separately from the drive train or from the electric motor 12, respectively.The electric motor 12, which is for example a three-phase asynchronous motor or synchronous motor, can be operated selectively in the electromotive operation with a positive drive torque which represents a total drive torque of the hybrid drive 10 alone or together with the torque of the internal combustion engine 14, or in the generator operation with a negative electromotive torque which corresponds to a braking torque or recuperation torque. In motor operation, the electric motor 12 drives the drive shaft 16-supported alone or by the internal combustion engine torque of the internal combustion engine 14-while consuming electrical energy (current). The electric motor 12 draws it from a traction battery 26, which is designed in particular as a rechargeable high-voltage battery. In the generator mode, on the other hand, the electric motor 12 is driven by the internal combustion engine 14 or a coasting mode of the vehicle and converts the kinetic energy into electrical energy for charging the traction battery 26 or for supplying an on-board power grid, not shown.In addition, the traction battery 26 has a charging connection 28 for recharging by an external power source 30.The electric motor 12 is switched between motor and generator operation by power electronics 32, which simultaneously undertakes a possibly required reversal between direct current and alternating current.The operation of the internal combustion engine 14 and of the power electronics 32 is controlled by an engine control unit 34, in which a control unit 36 for controlling the hybrid drive 10 according to the invention is integrated. In particular, the control unit 36 comprises a computer readable program algorithm. Alternatively, the control unit 36 can also be embodied separately from the engine control unit 34. The engine control unit 34 or the control unit 36 receives various current operating parameters of the vehicle, such as a rotational speed n of the crankshaft of the internal combustion engine 14 or of the drive shaft 16 and a load L of the internal combustion engine 14. The control unit 36 controls the electric motor 12 (via the power electronics 32) and / or the internal combustion engine 14 in an operating mode dependent on the operating parameters.A distance from a charging station can be entered by a user via a first operating element 38 and transmitted as an operating parameter to the control unit 36. The controller 36 selects the mode of operation such that the anticipated state of charge of the traction battery 26 is reached a predefined state of charge after the input distance has travelled.A reserved electrical range can be entered by the user via a second operating element 40 and transmitted to the control unit as an operating parameter. The controller 36 selects the mode of operation such that the state of charge of the traction battery 26 does not decrease below a reserved state of charge corresponding to the input reserved electric range.The first operating element 38 and the second operating element 40 are realized on a touchscreen 42.FIG. 2 shows a display content of the touch screen 42.The first operating element 38 is designed as a so-called slider, which the user can pull horizontally over the touchscreen 42 with his finger. In this case, control signals are generated which correspond to distances to the charging station of from zero kilometers (left) to over five hundred kilometers (right). The first operating element 38 is currently at forty-five kilometers, which can be seen on the basis of a scale 44. Alternatively, the first operating element 38 can also be displaced to the left (minus key) and to the right (plus key) via keys 46. For this purpose, the user only needs to tap on the buttons 46. Operating parameters are generated from the control signals, which the control unit takes into account when selecting the operating modes.The second operating element 40 is likewise designed as a slider, which the user can pull horizontally over the touchscreen 42 with his finger. In this case, control signals are generated which correspond to a reserved electrical range of zero kilometers (left) to fifty kilometers (right). Currently, the second operating element 40 is at thirty kilometers, which can be seen on the basis of a scale 48. Alternatively, the second operating element 40 can also be moved to the left (minus key) and to the right (plus key) via keys 50. For this purpose, the user only needs to tap on the buttons 50. Operating parameters are generated from the control signals, which the control unit takes into account when selecting the operating modes.A range display can be seen in a field 52 of the touchscreen 42. The range indicator is divided into a reserved electric range field 54, a remaining electric range field 56, and an internal combustion engine range field 58. The range field 54 corresponds in terms of extent to the setting of the second operating element 40. Here, fifteen kilometers of remaining range for electric driving fades. The range field 56 corresponds to the range that can be covered with the internal combustion engine 14 taking into account a tank content.List of reference characters10 Hybrid drive 12 Electric motor 14 Internal combustion engine 16 Drive shaft 18 Drive axle 20 Transmission 22 Clutch 24 Additional clutch 26 Traction battery 30 External power source 32 Power electronics 34 Engine control unit 36 Control unit 38 First operating element 40 Second operating element 42 Touchscreen 44 Scale 46 Buttons 48 Scale 50 Buttons 52 Field 54- 58 Range fields

Claims

Method for controlling a hybrid drive (10) for a vehicle, wherein the hybrid drive (10) has an electric motor (12) for an electric motor drive of the vehicle, an internal combustion engine (14) for an internal combustion engine drive of the vehicle, a traction battery (26) for supplying energy to the electric motor (21), a charging connection for charging the traction battery (26) by an external current source and a control unit for actuating the electric motor (12) and / or the internal combustion engine (14), in which the control unit (36) actuates the electric motor (12) and / or the internal combustion engine (14) in an operating mode dependent on operating parameters, wherein a distance from a charging station is input by a user via a first operating element (38) and is transmitted as an operating parameter to the control unit (36), and wherein the control unit (36) selects the operating mode in this way, a state of charge of the traction battery (26) that is expected to reach a predefined state of charge after the distance has been entered, characterized in that a reserved electric range is entered by the user via a second operating element (40) and is transmitted as an operating parameter to the control unit (36), and in that the control unit (36) selects the operating mode such that the state of charge of the traction battery (26) does not fall below a reserved state of charge that corresponds to the reserved electric range entered, wherein the currently selected operating mode is changed on the basis of a changed weight of the vehicle, wherein the control unit (36) continuously monitors the currently selected operating mode at predefined time intervals or predefined distance intervals.The method of claim 1, characterized in that the predefined state of charge is set equal to the reserved state of charge if the predefined state of charge is less than the reserved state of charge.Method according to Claim 1 or 2, characterized in that the first operating element (38) and / or the second operating element (40) is / are formed on a touchscreen (42).Method according to Claim 3, characterized in that the first operating element (38) and / or the second operating element (40) is / are designed as a slider.Hybrid drive (10) for a vehicle, wherein the hybrid drive (10) has an electric motor (12) for an electric motor drive of the vehicle, an internal combustion engine (14) for an internal combustion engine drive of the vehicle, a traction battery (26) for a power supply of the electric motor (12), a charging connection for charging the traction battery (26) by an external current source and a control unit (36) for actuating the electric motor (12) and / or the internal combustion engine (14), which is designed to actuate the electric motor (12) and / or the internal combustion engine (14) in an operating mode dependent on operating parameters, wherein a distance from a charging station can be input by a user via a first operating element (38) and can be transmitted as an operating parameter to the control unit (36), and wherein the control unit (36) is designed to select the operating mode in such a way, a state of charge of the traction battery (26) that is expected to reach a predefined state of charge after the distance has been entered, characterized in that a reserved electric range can be entered by the user via a second operating element (40) and can be transmitted as an operating parameter to the control unit (36), and in that the control unit (36) is designed to select the operating mode such that the state of charge of the traction battery (26) does not fall below a reserved state of charge that corresponds to the reserved electric range entered, wherein the currently selected operating mode can be changed on the basis of a changed weight of the vehicle, wherein the control unit (36) is designed to continuously monitor the currently selected operating mode at predefined time intervals or predefined distance intervals.Hybrid drive (10) according to Claim 5, characterized in that the first operating element (38) and / or the second operating element (40) is / are formed on a touchscreen (42).Hybrid drive (10) according to Claim 5 or 6, characterized in that the first operating element (38) and / or the second operating element (40) is / are designed as slide regulators.

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