DE102006001272B4 - Powertrain for a full hybrid drive and method and means for operating the powertrain - Google Patents

Abstract

A powertrain for a full hybrid drive for a motor vehicle (31) comprising an internal combustion engine (2) having an output shaft (8), a main electric motor (3) by means of which only a predetermined power for moving the motor vehicle (31) from the state can be generated A clutch (4) by means of which the output shaft (8) is selectively connectable to the main electric motor (3), a transmission (5) coupled to the main electric motor (3), and an auxiliary electric motor (6) connected to the internal combustion engine (2) and by means of which the internal combustion engine (2) can be started at least at a current, exceeding a predetermined minimum temperature temperature of the internal combustion engine (2), characterized in that the main electric motor (3) is designed as a starter generator, that the predetermined minimum temperature is greater than 10 ° C, and that the mechanical power of the auxiliary electric motor is not sufficient, the internal combustion engine (2) reliably z Start u when the operating temperature is below the minimum temperature.

Description

The present invention relates to a powertrain for a full hybrid drive for a motor vehicle, a method for operating the drive train and means for operating the drive train, in particular a control device for carrying out the method.

Hybrid powertrains for motor vehicles are of interest for their high efficiency and relatively low emissions during operation.

In what are known as full hybrid drives, an internal combustion engine and at least one electric motor are provided as drive sources in a drive train, which is generally understood to mean at least the drive sources and the elements mechanically connected to the drive sources up to a transmission, which are both suitable to move a motor vehicle each alone and in combination with each other.

Out EP 1564 055 A2 a powertrain for a hybrid drive for a motor vehicle is known, comprising an internal combustion engine, an electric motor, a converter, permanently connected to the electric motor gear, a clutch with variable torque capacity for selectively coupling the internal combustion engine with the electric motor and the transmission and a controller for controlling the Coupling state of the clutch and the torque generated by the internal combustion engine when starting comprises. During operation, the torque capacity of the clutch is set in response to a deviation between a speed setpoint of the transmission input shaft and the actual speed value, so that the internal combustion engine supplies additional torque to the transmission input shaft.

However, this drive train has the disadvantage that a startup clutch must be used as the clutch, which is susceptible to wear and takes up space. In addition, in an operating condition in which the internal combustion engine has an operating temperature for steady state operation but is stationary and only the electric motor is operating, starting the internal combustion engine by means of the electric motor by closing the clutch can result in a significant drop in torque or speed that is uncomfortable for occupants of a vehicle powered by this drivetrain.

In DE 699 22 603 T2 is a drive train with the features of the preamble of claim 1 described.

In W02004 / 014700 A1 a computer system for controlling a powertrain is described. For vehicles, a multi-layered modular software design known in the art has been developed and, in addition, concrete procedures for practical implementation are indicated. For this purpose, a computer system with a software architecture is specified, which contains concrete function assignments and interfaces with exchangeable modular plug-ins. With the aid of a prioritization procedure, these plug-ins can be queried independently of the number and mode of operation of the requesting systems for flexibility. A method for powertrain control of a motor vehicle is divided into five phases from the characterization of the environmental influences to the start of the optimal operating point. In a computer system with an object-oriented software system, this method can also be used.

In DE 196 32 074 A1 is a part of a powertrain described. For simplified construction while reducing the weight of a starter generator provided for starting an internal combustion engine, its valves are adjusted in the sense of a minimum compression in combination with a valve-controllable combustion engine when the starter-generator initially accelerates the ignition of the internal combustion engine.

In WO 02/06072 A1 a control unit is described which is used to adjust the transmission ratio of a transmission arranged together with an engine in a drive train in order to bring about a brake assist by the braking torque of the engine. It has a plurality of signal inputs for receiving the desired braking torque and the rotational speed of the engine and / or the vehicle speed, a calculation unit for determining the transmission ratio suitable for achieving the desired braking torque of the transmission in dependence on the desired braking torque and the speed or the vehicle speed, and a signal output for outputting a control signal determining the transmission ratio of the transmission. In this case, an electric generator is arranged in the drive train, which feeds a battery and has an additional braking torque. To determine the state of charge of the battery, a measuring unit is provided which is connected on the output side to the calculation unit in order to set the transmission ratio of the transmission as a function of the state of charge of the battery.

In DE 199 30 391 A1 a hybrid propulsion system for a vehicle is described which includes a first electric motor in driving relation with at least one driven wheel Heat engine, such as an internal combustion engine, a second electric motor in drive connection with this machine, and a coupling for coupling the machine to the driven wheel or for decoupling the machine from the driven wheel. Immediately after or substantially simultaneously with a command for engaging the clutch, a control unit based on a measurement of the speed of the driven wheel receives data of a maximum input torque that can be absorbed by the second motor from the engine, and data of a maximum output torque that the first motor can produce. The control unit compares the torque demand command with the retrieved data and selects one of a plurality of different protocols for operating the first and second electric motors and the heat engine.

In US 5,713,425 a hybrid powertrain for a motor vehicle is described which includes an internal combustion engine and a transmission assembly providing a first selectively switchable torque flow path. It further includes an electric motor-generator unit that provides a second switchable torque flux path disposed between the output of the first torque flow path and the drive wheels. Through the use of a suitable control system including the necessary control algorithms, the electric motor-generator unit can be operated to supply torque to the drive wheels while interrupting torque flow in the first torque flow path during a gear shift or disengagement. By the mutual control of two drive sources, driveability can be improved along with an improvement in engine exhaust emissions. In addition, the second electric motor-generator unit in the second torque flow path may be used to electrically start the vehicle immediately upon a request from the operator. This powertrain capability allows for powered off engine operation during vehicle coasting and standstills without loss of driveability. During the electrical start-up, the mutual control of the drive sources allows the engine to be restarted and then gradually take over the drive task of the motor-generator unit.

The present invention is therefore an object of the invention to provide a powertrain for a full hybrid drive and a method for operating the powertrain, which allows a starting the engine in the hot state during operation of the electric motor without a significant torque or speed drop , as well as means for operating the powertrain provide.

The object is achieved by a drive train for a full hybrid drive for a motor vehicle with the features of claim 1 and in particular a drive train comprising: an internal combustion engine with an output shaft, a main electric motor, by means of which only a predetermined power for moving the motor vehicle from the Stand is generated, a clutch by means of which the output shaft is selectively connectable to the main electric motor, coupled to the main electric motor gearbox, and an auxiliary electric motor which is connected to the internal combustion engine and by means of which the internal combustion engine at least at a current, a predetermined minimum temperature exceeding temperature the internal combustion engine can be started.

The drive train according to the invention thus has as torque sources on the one hand via the internal combustion engine, which may be an engine of any type or a combus tion engine. For example, it may be gasoline, Wankel or diesel engines. Turbocharged or supercharged engines may also be used, for example. Further, for example, internal combustion engines can be used with intake manifold injection or direct injection. For the control or the operation of the internal combustion engine, a control device, which can also be understood as an operating device for the internal combustion engine, may be provided which controls the internal combustion engine, in particular in a conventional manner.

The drive train according to the invention further has the main electric motor, by means of which only a predetermined power can be generated. The power is selected so that it is sufficient to move the motor vehicle from the stand, possibly after implementation of the torque output by the transmission. Preferably, the main electric motor may have a power of more than 15 kW. Furthermore, it can preferably be an electric motor which is operated with high voltage, in the context of the present invention, a voltage greater than 60 V is understood.

The main electric motor, more precisely its rotating shaft, is mechanically connected to the transmission, more precisely its input shaft, for transmitting torques, so that a corresponding torque can be available after the transmission, depending on the choice of the ratio.

An output shaft of the internal combustion engine, for example a crankshaft, is coupled to the main electric motor, more precisely its rotating shaft, via the clutch, by means of which the output shaft can be selectively connected to the main electric motor for the transmission of torques. The coupling may in particular also include, for example, an electrical or hydraulic operating or actuating device, by means of which by coupling suitable, preferably electrical clutch control signals, the clutch can be engaged or disengaged. Preferably, the rotating shaft, ie the output shaft of the main electric motor is connected at one end to the clutch and at the other end to the transmission, so that there is a linear arrangement. When coupled or engaged clutch so the torques of the engine and the main electric motor can sum so that so far a parallel hybrid drive can be realized in which, depending on the state of the clutch, the internal combustion engine, the main electric motor or both provide the necessary torque.

The main electric motor is further designed, depending on the internal combustion engine used, to use it for starting the internal combustion engine also in the cold state, i. is suitable at a temperature below the minimum temperature, for which the clutch must be engaged.

If the internal combustion engine were restarted by the main electric motor in an operating phase in which it has already reached the operating temperature but is switched off, a noticeable loss of torque could occur at the output shaft of the transmission, which should be avoided.

Therefore, the auxiliary electric motor is provided, which is mechanically connected to the internal combustion engine, more specifically a suitable for starting shaft of the internal combustion engine, such as the crankshaft for transmitting torque and is designed so that it is suitable for starting or starting the internal combustion engine, if the internal combustion engine has at least one temperature exceeding the predetermined minimum temperature. The temperature of the internal combustion engine can be given, for example, by the oil temperature or the cooling water temperature of the internal combustion engine during steady-state continuous operation. The predetermined minimum temperature, the power of the auxiliary electric motor and a gear ratio of an optionally existing transmission between the internal combustion engine and the additional electric motor are selected as a function of each other. In principle, the auxiliary electric motor must be able to start the internal combustion engine if its temperature exceeds the minimum temperature. Further, the minimum temperature is chosen so that it falls below the operating temperature of the internal combustion engine during steady-state operation. Preferably, the minimum temperature is at least 10 ° C, more preferably at least 20 ° C smaller than the normal operating temperature of the internal combustion engine in steady-state operation. In order to be able to select the auxiliary electric motor as small as possible, but to enable a start by the same as early as possible in an operating cycle, a minimum temperature greater than 10 ° C, more preferably greater than 15 ° C, most preferably greater than 30 ° C.

The auxiliary engine further has a mechanical power that is insufficient to reliably start the engine in a cold state. By eliminating the cold start capability, such an additional electric motor can be comparatively small, lightweight and compact, so that a compact design with a simple and therefore cost-effective control can be achieved. The maximum electric drive power of the auxiliary electric motor is preferably in the range less than 5 kW.

The mechanical connection between the internal combustion engine and the auxiliary electric motor may have another clutch to separate the internal combustion engine and the auxiliary electric motor, or be clutchless, i. do not have a said further coupling, so that the connection is permanent.

To start the internal combustion engine in a state in which the temperature exceeds the minimum temperature, especially in the warm operating condition, the internal combustion engine can now be started by means of the auxiliary electric motor during operation of the main electric motor with disengaged or disengaged clutch without the drive of the motor vehicle by the Main electric motor is affected. A noticeable torque change, in particular a noticeable torque drop, can thus be avoided.

In order to allow a fast and energy-efficient starting of the internal combustion engine, a start-stop-capable internal combustion engine with a corresponding control unit is preferably used as the internal combustion engine with the control unit. In this case, the piston position can be determined in the cylinders of the corresponding internal combustion engine and injected into the cylinder first fuel to start and then ignited, in which the piston is in working position. Such start-stop-capable internal combustion engines are, for example, in DE 31 17 144 A1 described.

Basically, as the main electric motor, any electric motor corresponding power or a combination of multiple electric motors. In particular, a synchronous or asynchronous motor can be used. However, in order to allow charging of an energy store, from which the main electric motor is supplied with energy, in a simple manner, the drive train preferably comprises the main electric motor in the form of a starter-generator. In the context of the invention, a starter generator is generally understood to mean an electric machine or a combination of electric machines, which can be operated both as drive or motor and as generator. In other words, the main electric motor is preferably a starter-generator, wherein the drive train may comprise at least one additional circuit, by means of which the main electric motor can be used either as a drive or as a generator. This embodiment has the advantage that such a compact and simple construction of the drive train can be achieved. Particularly preferably, at least one mechanical part of the clutch is integrated into the rotor of the starter-generator.

In principle, the main electric motor can be coupled in any way with the transmission, more precisely its input shaft. For example, when using a transmission with a continuously variable transmission (so-called CVT transmission), a coupling via a shiftable clutch is conceivable. Preferably, however, the main electric motor is coupled to the transmission clutchless. At best, at most a rigid coupling is provided. Since the electric motor is suitable for starting and connected via the clutch with the internal combustion engine, a switchable clutch in front of the transmission is not necessary. This embodiment has the advantage that on the one hand a particularly simple, lightweight construction can be achieved.

As a transmission can be used basically any gear with discrete gear ratios or continuously variable ratio. As a transmission, for example, manual transmission, automated manual, dual-clutch or automatic transmission can be used. Preferably, the transmission is a converterless transmission, in particular a converterless automatic transmission. This is understood to mean that the transmission, in particular if it is an automatic transmission, has no, in particular hydrodynamic, converter. This has the advantage that, on the one hand, a very simple construction of the transmission is achieved and, on the other hand, power losses, in particular slip losses, and unfavorable dynamic behavior due to the use of the converter are avoided.

In particular, the transmission may comprise a planetary gear. This advantageously allows a simple and compact construction of the transmission, which can preferably also be designed as an automatic transmission.

In principle, any switchable clutch can be used as a coupling between the internal combustion engine and the main electric motor, by means of which the output shaft can be selectively separated from or connected to the main electric motor as a function of electrical clutch control signals. Preferably, however, the clutch is a disconnect clutch. Under a clutch is in this case a clutch understood that is suitable to permanently connect two waves with approximately the same speed to each other or decouple from each other, but not permanently or very often waves with very different speeds.

Such a coupling at very different speeds occurs, for example, in known drive trains during startup. In particular, disconnecting clutches are understood to be switchable clutches which, owing to their mechanical design or the activation, can occupy essentially only two states, the fully engaged or disengaged. This embodiment has the advantage that separating clutches are made more compact, so that the separating clutch takes up less space. In particular, they are also better suited for integration in a starter generator.

In principle, any electric motor of sufficient power can be used as an additional electric motor for starting the operating-temperature internal combustion engine. However, it is preferred in the powertrain that the auxiliary electric motor is designed to operate with low voltage. Under low voltage is in the context of the present invention, a voltage, preferably DC voltage, less than 60 V, preferably of a maximum of 36 V understood. A cold state of the internal combustion engine is present when their current temperature falls below the minimum temperature.

Particularly preferably, the auxiliary electric motor is designed as a starter-generator. For this purpose, this particular electrical connected to an operating device, by means of which he can optionally, in particular to corresponding auxiliary electric motor signals, as a drive or generator can be operated. This has the advantage that the additional electric motor can also be used to generate energy when the internal combustion engine is working. In particular, when using an auxiliary electric motor, which is to be connected directly or at the DC side input of an inverter to the electrical system of the motor vehicle, so a charge of a battery of the electrical system or a supply the on-board network with electrical energy easily done.

The connection of the auxiliary electric motor with the internal combustion engine can be done via any gear and / or a non-switchable or switchable coupling. In a preferred embodiment, a traction mechanism or friction gear is provided in the drive train, which connects the auxiliary electric motor with the internal combustion engine. As a traction means, for example, belts, in particular flat, wedge or toothed belts, or chains come into consideration. This embodiment has the advantage that the auxiliary electric motor can be arranged next to the internal combustion engine, wherein the shaft of the auxiliary electric motor and the output shaft of the internal combustion engine can preferably run at least approximately parallel, and thus the space requirement is reduced. In addition, when using a belt drive already known engine blocks for the internal combustion engine can be used without significant changes would be necessary.

Particularly preferred is a belt drive with controllable belt tension is used, which has the advantage that the belt tension can be adjusted depending on the operating mode of the auxiliary electric motor.

According to another embodiment, a gear transmission is provided in the drive train, which connects the auxiliary electric motor with the internal combustion engine. This embodiment has the advantage that no slippage occurs as in belt or friction gear and thus a high efficiency is achieved. In addition, advantageously known engine blocks of internal combustion engines can be used for non-hybrid drives, when the auxiliary electric motor is coupled via the gear transmission with the shaft of the internal combustion engine, via which the torque of the starter is otherwise initiated.

Preferably, a device is provided, by means of which the additional electric motor is connected to an electrical system of the motor vehicle for charging a vehicle power supply battery. In particular, this device can be an operating device for the additional electric motor, which also serves for operation as a drive and may include an inverter depending on the type of motor. This development advantageously allows a charging of the electrical system via the additional electric motor, if this is designed as a starter-generator.

Particularly preferably, the additional electric motor designed as a starter-generator is connected to a, preferably separate from the electrical system, energy storage for rapid storage generated and output stored electrical energy. Under a separation from the electrical system is understood that the energy storage for the auxiliary electric motor is not directly connected, but at most via voltage converter to the electrical system. On the one hand, this embodiment has the advantage that when the internal combustion engine is started with the additional electric motor, energy can first be used from the energy store, so that a substantial voltage drop in the vehicle electrical system caused by starting will not occur. In addition, an energy storage can be used, which operates at a higher operating voltage than the electrical system, which limits the size of the currents occurring to an operating device for the auxiliary electric motor. Preferably, the energy storage comprises a so-called double-layer capacitor ("double-layer capacitor", also referred to as "ultra-cap") which can often be charged and discharged very quickly without being damaged.

In order to enable charging of a vehicle electrical system battery, it is preferred that the additional electric motor or an operating device for this is connected via an electrically controllable switching unit with the energy storage, that the switching unit to appropriate switching signals the additional electric motor or the operating device with either the energy storage or a Output to a vehicle electrical system connects, and that the auxiliary electric motor is designed so that it can supply the on-board network without an additional voltage converter, in particular a DC-DC converter when operating as a generator with a corresponding position of the electrical switching unit. This has the advantage that on the one hand when operating the auxiliary electric motor as drive significantly lower currents occur, but on the other hand, a supply of the on-board network without losses by a voltage conversion is possible.

Further, it is preferred that the drive train has a voltage converter connected to an energy storage device for supplying the main electric motor, which converts the voltage supplied by the energy store to the voltage of a predetermined vehicle electrical system of the motor vehicle. This embodiment allows advantageously to supply the electrical system with voltage even when the internal combustion engine.

The object is further achieved by a method having the features of the claim and in particular a method for operating a full hybrid drive with a drive train according to the invention, ie a drive train comprising an internal combustion engine with an output shaft, a main electric motor, by means of which alone a predetermined power for moving the Motor vehicle from the state can be generated, a clutch by means of which the output shaft is selectively connectable to the main electric motor, coupled to the main electric motor gearbox, and an additional electric motor which is connected to the internal combustion engine and by means of which the internal combustion engine at least at a current, a predetermined Minimum temperature exceeding temperature of the internal combustion engine can be started. In the method, temperature signals representing a temperature of the internal combustion engine are detected, and control signals for an operating device for the auxiliary electric motor are formed when the internal combustion engine, the main electric motor, a detected temperature exceeds the predetermined minimum temperature, and at least one further predetermined operating condition and delivered to this, so that the auxiliary electric motor starts the engine.

The object is further achieved by a control device with the features of the claim and in particular a control device for controlling a full hybrid drive with a drive train according to the invention, i. a powertrain comprising an internal combustion engine with an output shaft, a main electric motor, by means of which a predetermined power for moving the motor vehicle from the state can be generated, connected to the output shaft and the main electric motor coupling, by means of which the output shaft is selectively connectable to the main electric motor, with a the transmission coupled to the main electric motor, and an additional electric motor, which is connected to the internal combustion engine and by means of which the internal combustion engine can be started at least at a current, exceeding a predetermined minimum temperature temperature of the internal combustion engine. The control device has at least one output for outputting main electric motor signals to an operating device for operating the main electric motor, for outputting clutch control signals for disengaging or engaging the clutch, for outputting auxiliary electric motor signals to an operating device for the auxiliary electric motor, for outputting signals a control device for the internal combustion engine and the output of transmission signals to the transmission and at least one input for receiving temperature signals representing a temperature of the internal combustion engine, and is adapted to detect temperature signals and with the internal combustion engine, working main electric motor, a detected temperature , Which exceeds the predetermined minimum temperature, as well as to fulfill at least one further predetermined operating condition control signals for an operating device for the auxiliary electric motor to form and deliver to this, so that the Zusat The electric engine starts the engine.

Under a working electric motor is understood to be an electric motor, which generates mechanical energy or torque by supplying electrical energy. In particular, the main electric motor, when working, drive the motor vehicle via the transmission.

The control device can in principle be of any desired design, e.g. as analog or fixed digital circuit. However, the control device preferably has a memory in which instructions of a computer program are stored, and at least one processor connected to the memory, which executes the operating method according to the invention when the instruction is executed.

The object is therefore also achieved by a computer program for a data processing device to be connected to the drive train according to the invention with a processor comprising instructions in the execution of which the processor and the data processing device perform the operating method according to the invention. In particular, when the instructions are executed, the processor detects temperature signals and forms control signals for an operating device for the auxiliary electric motor with the internal combustion engine, working main electric motor, a detected temperature exceeding a predetermined minimum temperature, and fulfilling at least one further predetermined operating condition and outputs the control signals to the latter so that the auxiliary electric motor starts the engine.

The data processing device, which may generally comprise at least one processor or several cooperating processors, may in particular be provided by the said control device with at least one processor. However, it is also possible for at least parts of the computer program to be executed by at least one of the operating devices and / or the control device for the internal combustion engine.

Another object of the invention is a storage medium with a computer program stored thereon. Non-volatile memories, such as flash memories, EEPROMs, and data carriers can be considered as the storage medium.

In the control device, only one output needs to be provided, over which all signals are output. This is the case in particular when a serial bus, for example a CAN bus, is used for communication. It is However, it is also possible to use a separate output for each signal.

The control device also has an input for the temperature signals, which reflect the temperature of the internal combustion engine. As already stated above, the temperature can be given, for example, by the oil temperature or the cooling water temperature of the internal combustion engine during steady-state continuous operation. To form corresponding temperature signals, for example, the internal combustion engine may have a corresponding temperature sensor whose signals, optionally after processing in z. B. the control unit of the internal combustion engine, are delivered to the control device. However, the physical arrangement of the temperature sensor signal processing may be on other devices.

In the simplest case, the operating devices can only be driver circuits or control control devices and / or actuation or adjusting devices in the case of the transmission or the clutch. In particular, the operating devices for the main and auxiliary electric motor may include inverters for converting DC voltages of respective energy stores into AC voltages for the motors, provided that they operate with AC voltage. The control unit for the internal combustion engine is to be regarded in this respect as an operating device for the internal combustion engine.

In general, the overall control of the hybrid drive with the drive train, the control device, the operating devices and the control unit can be physically assigned to the control device, at least one of the operating devices or the control unit as desired, in whole or in part. The functions or facilities can also be integrated.

Preferably, the overall control is hierarchical in the sense that the operating devices themselves carry out details of the control and, for this purpose, receive the necessary commands or signals from the control device, which in particular are connected to operating devices to be actuated by the driver, for example an accelerator pedal and / or a brake pedal can be.

The start of the internal combustion engine by the additional electric motor takes place only when a plurality of conditions and others. for the operating state of the drive train. These conditions may be tested in any order, provided such testing is not already anticipated by the most recent changes in operating condition. In particular, a start takes place only when the internal combustion engine is stationary, the main electric motor is operating and the detected temperature of the internal combustion engine exceeds the minimum temperature. Since the clutch must be disengaged when the internal combustion engine is stationary and the main electric motor is operating, and in particular must have been disengaged beforehand, the condition of the clutch does not necessarily have to be rechecked. In addition, the further predetermined operating condition must be met, which can be checked and which decides whether the internal combustion engine should be started. For example, can be checked as a further operating condition, if the rotational speed of the main electric motor is so high that the engine can be operated at the speed trouble-free.

In order to start the engine easily and quietly even in a cold state, clutch control signals are formed and delivered in the operating method for starting the engine in a cold state with the main electric motor clutch on the clutch disengages, and it is checked whether the transmission in a Neutral or neutral position is. If this is not the case, a transmission signal is generated and delivered, to which the transmission is switched to an idle or neutral position, and then control signals for starting the internal combustion engine are formed and discharged by the main electric motor. The control device is for this purpose further formed and the computer program contains such instructions that the control device or the processor when executing the instructions for starting the internal combustion engine in the cold state when the main electric motor forms and outputs clutch control signals to which the clutch engages, checks, if the transmission is in an idle position, if not, generating and outputting a transmission signal toward which the transmission is shifted to an idle position, and then control signals for starting the engine by the main electric motor forms and gives up. The control signals can be delivered directly to the main electric motor or the internal combustion engine, but preferably to the operating device for the main electric motor or the control unit for the internal combustion engine. A cold state is present in particular when the current temperature of the internal combustion engine falls below the predetermined minimum temperature. This embodiment has the advantage that the necessary for a cold start of the engine large starting torque can be applied simply by the also provided for driving or driving main electric motor without any special effort.

The operating method, the control device and the computer program, hereinafter referred to as Operating program referred to allow a simple way of operating the powertrain in a hybrid drive. In particular, the advantage is achieved that, as already stated above for the drive train, a starting of the internal combustion engine can be achieved without a significant or significant speed or torque drop at the main electric motor.

In order to be able to connect the internal combustion engine or its output shaft to the main electric motor, it is preferred in the method that after starting the internal combustion engine determines a current speed of the main electric motor, the internal combustion engine and / or the auxiliary electric motor is driven by output of appropriate signals so that the speed of the engine and the main electric motor are matched to each other, and coupling control signals are formed for the clutch and delivered to this, on which the clutch engages. For this purpose, the control device is preferably designed in such a way and the computer program preferably comprises such instructions that the control device or the processor determines a current rotational speed of the main electric motor when the instructions are executed after starting the internal combustion engine, by outputting corresponding signals the internal combustion engine and / or the auxiliary electric motor controls so that the speed of the engine and main electric motor are matched to each other, and forms clutch control signals for the clutch and outputs to this, to which the clutch engages. This development advantageously allows for a particularly gentle connection of the engine running at idle with the main electric motor. Furthermore, a very fast adaptation can be made possible, since the internal combustion engine does not have to be brought to the necessary speed solely on its own. The signals for controlling the internal combustion engine and / or the auxiliary electric motor can be delivered in particular to the control unit or the corresponding operating device.

Further, in the method, it is preferable to check whether starting from the state is desired, and if so, to form and output main electric motor and / or clutch control signals so that the clutch is disengaged or disengaged and the operating means for the main electric motor drives it to start only with the main electric motor. For this purpose, the control device is preferably designed and to the computer program preferably includes such instructions that the controller or the processor when executing the instructions upon detection of a startup Hauptmotoromotor- and / or clutch control signals forms and outputs, so that the clutch disengages or disengaged is maintained and the operating means for the main electric motor drives it to start only with the main electric motor. This development has the advantage that a start-up can take place solely with the main electric motor without the actuation of a starting clutch or start of the internal combustion engine. For detecting a start-up operation, it can be checked, for example, whether the motor vehicle is stationary and the driver actuates the accelerator pedal.

In a slowing down the ride, the case may occur that when using only one clutch without slip capability, the speed of the output shaft of the engine drops so far that the engine can not be operated smoothly. It is therefore preferable in the method that it is checked whether the current rotational speed of the main electric motor and / or a desired torque are smaller than predetermined corresponding limit values, and if this is satisfied, a clutch control signal is formed and output, so that the clutch disengages , For this purpose, the control device is preferably designed and the computer program includes such instruction that the control device or the processor when executing the instructions checks whether the current speed of the main electric motor and / or a desired torque are smaller than predetermined limits, and, if so is, forms a clutch control signal and outputs, so that the clutch disengages. The further drive then takes place solely with the main electric motor. The limit values can be predefined as a function of the internal combustion engine used and, if appropriate, of the further operating conditions, such as the current temperature of the internal combustion engine. The internal combustion engine can, depending on the state of the energy storage for the electric motors and / or other operating conditions, either be operated independently of the main electric motor, for example, to drive other units and / or then designed as a starter generator auxiliary electric motor, or stopped to the To reduce fuel consumption. In particular, the internal combustion engine does not need to be idled when the main electric motor serves as the sole driving source. An advantage of this development is that it allows to actually use between the internal combustion engine and gearbox except a disconnect clutch no further switchable clutches, in particular starting clutches.

In principle, it can not be ruled out that the internal combustion engine or the main electric motor fails at least partially. In case of failure of the internal combustion engine, after opening the clutch, the main electric motor can be used alone to drive. In the event of a defect Main electric motor or a defective operating device for the main electric motor, it is preferred in the method that it is checked whether there is a malfunction of the main electric motor or an operating device for this, and if this is the case and the internal combustion engine is, by supplying appropriate signals to an operating device for the auxiliary electric motor and to a control device for the internal combustion engine, the internal combustion engine is started and a clutch control signal for engaging the clutch is formed and delivered to the clutch. For this purpose, the control device is preferably designed and the computer program contains such instructions that the control device or the processor checks when executing the instructions whether there is a malfunction of the main electric motor or the operating device for this, and if so and the internal combustion engine is , By issuing appropriate signals to the operating device for the auxiliary electric motor and to the control unit for the internal combustion engine, the internal combustion engine starts, and, at least forms a clutch control signal for engaging the clutch and outputs. This option for an emergency operation of the drive train or the hybrid drive equipped therewith has the advantage that even with failure of the main electric motor or possibly necessary for its operation operating equipment equipped with the drive train motor vehicle can still be moved by its own power. If the clutch is still engaged or closed between the main electric motor and the internal combustion engine, preferably at least one clutch control signal is output to the clutch before the start of the internal combustion engine, toward which the clutch disengages. The internal combustion engine is thus decoupled for starting from the main electric motor and the associated output; otherwise coupling would make starting difficult or impossible. Furthermore, before the delivery of the clutch control signals for engagement preferably still at least one transmission signal is formed in order to engage a predetermined gear, preferably the lowest. The clutch control signals and / or the transmission signals are preferably selected so that the clutch is as soft as possible between the internal combustion engine and the main electric motor and the clutches in the transmission, if present, can take place. To carry out these steps, the control device is designed accordingly and the computer program contains corresponding instructions.

Further, it is preferred in the method that the additional electric motor is a starter-generator and is connected in response to at least one further control signal or whenever driven by the internal combustion engine generator, when the auxiliary electric motor not for starting the internal combustion engine and / or for synchronizing the Speeds of internal combustion engine and main electric motor is driven. If the auxiliary electric motor is designed as a starter generator, the control device is preferably designed further and the computer program contains such instructions that the additional electric motor is switched as a function of at least one further control signal or always as a generator driven by the internal combustion engine, if the auxiliary electric motor does not for starting the internal combustion engine and / or for synchronizing the rotational speeds of the internal combustion engine and main electric motor is driven. This embodiment offers the advantage that the auxiliary electric motor can be used to charge the energy store from which it is supplied and / or the vehicle electrical system. In particular, in this case, a DC-DC converter, which reduces the voltage of a high voltage power supply for the main electric motor to the level of the electrical system, either not be used in this working mode, which avoids corresponding losses, or possibly completely saved.

In order to achieve a high efficiency of the drive, the main electric motor is designed as a starter-generator. In the method, it is then preferable to check whether an energy storage is to be charged for supplying the main electric motor, and depending on the result of the test, a main electric motor signal is formed and discharged, in response to the main electric motor as a generator for charging the Energy storage is operated. For this purpose, the control device is preferably designed further and the computer program has such instructions that the control device or the processor checks when executing the instructions whether an energy storage device is to be charged for supplying the main electric motor, and depending on the result of the test, a main electric motor Signal forms and outputs, on the way the main electric motor is operated as a generator for charging the energy storage. In this way, the power supply of the main electric motor can be made possible in an advantageous manner. The main electric motor signal can in particular be delivered to the operating device for the main electric motor.

In addition to the condition for charging the energy storage, other conditions may be checked that must be met for charging to take place. For example, it can be checked whether a regenerative braking should take place or the internal combustion engine alone should drive the motor vehicle and at the same time the main electric motor for charging. This embodiment advantageously allows a very variable Low-consumption operation of the powertrain or hybrid drive.

Preferably, the output shaft of the internal combustion engine is connected to a flywheel. This has the advantage that a quieter run can be achieved when the engine is idling. The flywheel may be held in particular on the output shaft.

The invention also relates to a hybrid drive with a drive train according to the invention and a control device according to the invention. The hybrid drive preferably further comprises a control unit for the internal combustion engine and further operating devices for the electric motors, the transmission, the energy storage and optionally the clutch.

• 1 eine schematische teilweise Darstellung eines Vollhybrid-Antriebs mit einem Antriebsstrang und einer Steuereinrichtung nach einer ersten bevorzugten Ausführungsform der Erfindung, und
• 2 eine schematische teilweise Darstellung eines Vollhybrid-Antriebs mit einem Antriebsstrang und einer Steuereinrichtung nach einer zweiten bevorzugten Ausführungsform der Erfindung.

The invention will be further explained by way of example with reference to the drawings. Show it:

• 1 a schematic partial view of a full hybrid drive with a drive train and a control device according to a first preferred embodiment of the invention, and
• 2 a schematic partial view of a full hybrid drive with a drive train and a control device according to a second preferred embodiment of the invention.

A partial in 1 shown full hybrid drive for a motor vehicle 31 includes a powertrain and a controller 1 according to a first preferred embodiment of the invention and an electrical system for supplying the drive train and the control device with energy.

The powertrain includes an internal combustion engine 2 and a main electric motor designed as a starter generator 3 as drive sources, which via a coupling designed as a clutch 4 are connected, as well as one with the main electric motor 3 clutchless, ie without the use of a clutch or disengageable clutch connected gearbox 5 for changing the speed and torque on the output shaft 29 or the wheel not shown in detail. Next is also designed as a starter generator auxiliary electric motor 6 intended.

The internal combustion engine 2 , In the example, an internal combustion engine, in particular a 4-cylinder gasoline engine whose operation is a control unit 7 in response to control signals of the control device 1 controls, has the familiar facilities of an internal combustion engine, not all in 1 are shown, and receives fuel from a tank, also not shown. It gives its torque over an output shaft 8th Serving crankshaft with a held flywheel 9 to the following along the drive train facilities. A temperature sensor 10 detects the temperature of the cooling water of the internal combustion engine 2 as the temperature of the internal combustion engine and transmits corresponding temperature signals reproducing the temperature to the control unit 7 , via which the temperature signals, optionally after further processing, can be dispensed again.

The internal combustion engine 2 together with the control unit 7 form a start-stop-capable engine, ie an engine with a start optimization by a dependent on the position of the pistons in the cylinders of the engine start injection as in example DE 31 17 144 A1 is described, the contents of which is incorporated by reference in the description. In this case, for example, after determination of the position of the piston in the cylinders when the internal combustion engine is first carried out an injection and ignition in the cylinder, in which the piston is in working position.

The separating clutch 4 has a mechanical part 11 , which is designed as a friction clutch, and a in 1 for the sake of clarity separately shown operating device 12 , hereinafter referred to as clutch control signals control signals from the controller 1 receives and in dependence on the received clutch control signals the disconnect clutch 4 can put either in an engaged state or a disengaged state. Part of the mechanical part of the separating clutch 4 is for transmitting torque to the output shaft 8th and another part with a rotating shaft of the main electric motor 3 connected. Since the clutch is a disconnect clutch, it can essentially occupy only the said two states in which the parts or friction surfaces of the clutch are either pressed against each other or separated from each other with full force.

In the embodiment, the mechanical part 11 the clutch 4 designed so that one side or disc with the output shaft 8th is directly connected, and the other side or disc in a rotor of the main electric motor 3 is integrated.

The separating clutch 4 allows a purely electrical operation of the vehicle 31 alone with the main electric motor 3 and without the internal combustion engine 2 , The coupling 4 can be very simple and small, since they are in normal operation, as explained below, no Synchronization tasks needs to perform, but the speeds of the waves of the internal combustion engine 2 and main electric motor 3 be adapted for a comfortable engagement with other means described below. Only in emergency operation, which is also described above, can speed differences be compensated here.

The main electric motor 3 is, as already described, designed as a starter generator with integrated separating clutch part. It has a power and a torque, at least when choosing a suitable gear ratio 5 a start-up and at least low-speed driving alone with the main electric motor 3 allowed. Preferably, the main electric motor 3 as a high voltage motor, ie formed with supply voltages greater than 60V. For example, it can have a power of 75 kW. The main electric motor 3 is via an operating facility 13 in turn, the control in response to main electric motor signals of the control device 1 performs. This factory equipment 13 In this example, it has an inverter for converting DC voltage from the main electric motor 3 used three-phase AC voltage.

The gear 5 is with its input shaft directly without the interposition of a switchable coupling with the rotating shaft or output shaft of the main electric motor 3 connected. The gear 5 is designed as a converterless automatic transmission, so has no, for example, hydrodynamic torque converter, and has a planetary gear 14 , via clutches and brakes, not shown, inside the transmission 5 can be switched. This eliminates the torque converter otherwise own slip losses, its weight and associated with the converter dynamics disadvantages in response.

The clutches and brakes inside the transmission 5 are preferably designed so that in emergency operation in case of failure of the main electric motor 3 over the clutches and brakes of the planetary gear 14 a replacement starting possibility with the internal combustion engine 2 given is.

The gear changes are made by a transmission operating device 15 the transmission, the gear change to transmission signals of the control device 1 leads out. An output shaft 29 of the transmission 5 after the planetary gear 14 leads via a corresponding differential to the driven wheels.

The auxiliary electric motor 6 is also designed as a starter generator and with its rotating shaft via a belt drive 16 not with the disconnect clutch 4 connected end of the output shaft 8th connected. The auxiliary electric motor 6 serves on the one hand to start the operating-warm internal combustion engine and depending on the mode for synchronizing the speed of the internal combustion engine 2 On the other hand, it serves as a generator for the in 1 only in the form of a vehicle electrical system battery 17 , in the example a 12V battery, partly shown on-board network 30 of the vehicle 31 , It is therefore designed as a relatively small electric motor having a power that is significantly smaller than that of the main electric motor. Preferably, it is between 1 kW and 10 kW. For reasons outlined below, the supply voltage of an inverter for supplying the auxiliary electric motor 6 with operating voltage preferably greater than 12 V, but less than about 50 V, in the example to 20V, selected.

The auxiliary electric motor 6 is supplied via an operating device 19 in response to additional electric motor signals, which they from the control device connected to it via a signal connection 1 gets controlled. Analogous to the operating device 13 also has the operating equipment 18 on the already mentioned inverter for the implementation of the DC voltage of 20 V in example of the auxiliary electric motor 6 used three-phase AC voltage.

The electrical system comprises a total of three energy stores on three different voltage levels.

The first level, the lowest voltage level, in the example 12V, is the on-board level. In the electrical system 30 is the electrical system battery 17 provided for the energy supply of the electrical system 30 and the connected thereto, partly not shown in the figures electrical equipment is used.

To supply the auxiliary electric motor 6 the second voltage level is provided, which in the example has a voltage of 20 V in the example. At this level are an additional energy storage 18 and a switching unit 20 intended. The switching unit 20 is stuck with the facility 19 , more precisely the inverter of the operating device 19 the cache 18 and via a corresponding output with the electrical system 30 connected. The electrical switching unit 20 is via appropriate switching signals from the controller 1 controllable, so that the operating equipment 19 of the auxiliary electric motor 6 depending on the switching signals optionally with the additional energy storage 18 or the electrical system 30 is connectable. In particular, when connecting the operating device 19 with the additional energy storage can the Additional electric motor 6 be supplied with operating voltage.

As a result, on the one hand, when the operating voltage of, for example, 20 V is increased in comparison to the vehicle electrical system voltage, significantly lower starting currents and ohmic losses occur with the same electrical output. On the other hand, the auxiliary electric motor 6 designed so that he, if he does not serve as a drive, with appropriate position of the electrical switching unit 20 also for the electrical system 30 on the first voltage level, the generator function can take over without additional DC-DC converter. Next, the additional energy storage 18 optionally by the additional electric motor 6 be reloaded.

This additional energy store 18 is in the present example by a capacitive memory, a double-layer capacitor (Double Layer Capacitor, also called Ultracap) realized. This has advantages for the short-time operation occurring in the drive over other types of storage. The supply of the auxiliary electric motor 6 from the capacitive energy storage 18 gives the further advantage eg at high additional loads in the general wiring system 30 in that the starter operation is via the additional energy storage 18 energetically secured, as long as the necessary energy for the control device 1 and the operating equipment 12 . 13 . 15 and 19 and the controller 7 in the electrical system 30 still available. In particular, a voltage dip in the electrical system 30 at a start of the internal combustion engine 2 with the additional electric motor 6 be prevented.

By using the second voltage level, a sufficiently large starting torque can be ensured at moderate currents. As a result, a more favorable electrical and / or mechanical design of the auxiliary electric motor 6 possible; For example, a smaller volume and lower ohmic losses can be achieved when operating as a starter.

Due to the low voltage difference, it is not necessary to use a DC-DC converter between the first and second voltage level, which saves construction volume, weight and cost and reduces the complexity of the arrangement and error risks.

The main electric motor 3 operates on a third voltage level at high voltage, ie voltages above 60 V. For this purpose it has an in 1 not explicitly shown inverter in the operating device 13 and a safety device 27 with an energy storage for the main electric motor 3 or accumulator system 21 , in the example, a lithium-polymer battery high voltage system (LIPO HV system), connected, which has a sufficiently large voltage and sufficient energy for electric driving alone with the main electric motor 3 provides.

The first and third voltage levels are via a DC-DC converter 22 connected by the high voltage to the vehicle electrical system voltage, it is at a stationary internal combustion engine 2 allowed, the electrical system 30 via the then acting as a generator main electric motor 3 to supply. For charging the electrical system battery 17 However, this DC-DC converter usually requires the possibility of charging by means of the auxiliary electric motor 6 either not to be used for loading or can be omitted entirely in other embodiments. By decoupling the third voltage level from the first voltage level via the DC-DC converter 22 Strong fluctuations of the vehicle electrical system voltage can be avoided, which could be due to direct coupling by the strong traction current-dependent voltage in the third level.

For the operation of the powertrain, the control of the electrical system and in particular the operating equipment 12 , 13, 15 and 19 are used by the electrical system 30 powered controller 1 that's about a processor 23 and one with the processor 23 connected memory 24 with a non-volatile part. In the non-volatile part of a computer program is stored, which contains instructions in the processing of the processor 23 or the control device 1 Perform the operating procedure for operating the powertrain described below. It has a in 1 not shown input for driving and brake pedal signals of a driving or brake pedal of the vehicle 31 and optionally further signals, a temperature signal input 25 and outputs 26 , about the generated signals for the operating equipment 12 . 13 . 15 and 19 , the switching unit 20 and the controller 7 be delivered.

In the exemplary embodiment, a hierarchical control is provided as it, except for the procedures described below, in WO 02/2650 A1 is described.

The control device 1 performs its control tasks in response to accelerator pedal signals from the accelerator pedal of the vehicle 31, temperature signals of the temperature sensor 10 and, where appropriate, signals from the operating equipment, the control unit, further sensors of the vehicle 31 and the brake pedal off.

In the hierarchical structure used here, the control device generates the signals not directly for the engines, etc., but for the operating equipment, such as the facilities 12 . 13 . 15 and 19 and the controller 7 which in turn perform a lower-level control.

In the following, only the processes in the most important operating phases are shown.

The cold start takes place solely with the main electric motor 3 what about the gearbox before 5 set the neutral position and the disconnect clutch 4 , as far as it is not already closed, is engaged. After that, the main electric motor 3 or whose rotating shaft is set in motion, wherein the control unit 7 the internal combustion engine 2 accordingly to start.

More specifically, first checks the controller 1 whether the internal combustion engine is actually in cold operating condition. To do this, she checks whether a first start should be made after a long period of operational rest. If this is the case, a cold start is detected. Otherwise, the controller detects 1 Temperature signals via the temperature signal input 10 and checks whether the current detected temperature exceeds a predetermined minimum temperature. This minimum temperature is dependent on the temperature-dependent drag torque of the internal combustion engine 2, the power of the auxiliary electric motor 6 and the translation of the belt drive 16 selected. In the example is the configuration of internal combustion engine 2 , Additional electric motor 6 and belt transmissions 16 chosen so that the minimum temperature to 25 ° C and thus more than 20 ° C less than the operating temperature for steady-state operation of the internal combustion engine 2 , in the example 90 ° C, can be selected. In other embodiments, the minimum temperature may also be 10 ° C or 20 ° C below the steady state operating temperature. If the detected temperature falls below the minimum temperature, a condition for a cold start is detected.

Upon detection of a cold start, the controller checks 1 Continue, if the transmission 5 is in an idle or neutral position. If this is not the case, it generates at least one transmission signal and gives it to the transmission operating device 15 off, the gearbox pointing out 5 in an idle or neutral position switches.

At the same time, before or after, the control device 1 checks whether the clutch 4 is engaged. If this is not the case, first clutch control signals are formed and to the clutch 4 delivered on the clutch 4 engages and thus the main electric motor 4 and the output shaft 8th the internal combustion engine 2 connects to transmit a torque.

Thereafter, by delivering main electric motor signals to the operating device 13 the main electric motor 3 set in motion for starting and accelerated to a target speed. The main electric motor 3 turns the output shaft 8th , wherein the control device 1 Start signals to the control unit 7 emits. This will cause the internal combustion engine 2 started.

During operation of the hybrid drive, the controller performs 1 cyclically polls to detect the state of the hybrid drive or powertrain and the driver's requests in the form of accelerator pedal signals.

So she checks whether a start from the state is desired, what is detected, whether the vehicle 31 is and whether a corresponding accelerator pedal signal is present. If this is the case, it checks to see if the clutch 4 is still engaged. It then generates clutch control signals depending on the result of the test and outputs them to the clutch 4 so that the clutch is disengaged or disengaged. The internal combustion engine 2 is then from the main electric motor 3 decoupled. Therefore, the control device forms 1 in the sequence of main electric motor signals and outputs them to the operating device 13 from whereupon these the main electric motor 3 for starting alone with the main electric motor 3 controls. Depending on the condition of the internal combustion engine 2 this can continue to operate, for example, to warm up the auxiliary electric motor 6 to drive as a generator, or the internal combustion engine can be switched off or remain.

During operation of the hybrid drive, for example, after a long journey operating conditions may occur in which the internal combustion engine 2 Although it has a temperature close to the normal operating temperature, but is turned off. The drive source is then only the main electric motor 3 , It may then, depending on the torque request of the driver such as a sudden torque request, reproduced by appropriate accelerator pedal signals, be necessary, both the main electric motor 3 as well as the internal combustion engine 2 to operate in the so-called boost operation to provide a higher torque.

The control device 1 then first checks if the internal combustion engine 2 actually stands and the main electric motor 3 is in operation.

The control device 1 detected in this case by the temperature sensor 10 emitted temperature signals, which is the temperature of the internal combustion engine 2 play. It checks whether the detected temperature exceeds the specified minimum temperature. If the minimum temperature is exceeded and therefore recognized that the Internal combustion engine is in operating condition, checks the control device 1 for safety's sake, but optional, whether the disconnect clutch 4 is open. This test is actually not necessary, since with stationary internal combustion engine 2 and running main electric motor 3 the separating clutch must actually be open.

If this is also the case, a further operating condition is checked, for example, whether the rotational speed of the main electric motor 3 a predetermined minimum speed for trouble-free operation of the internal combustion engine 2 exceeds. In other embodiments, for example, the conditions can be checked as further operating conditions, whether engagement is predicted on the basis of the sensor signals and the operating conditions in the near past or whether a drop in the state of charge of one of the energy storage is to be expected. The corresponding criteria can be heuristic in particular.

If this is also the case, the control device generates 1 Control signals for the operating device 19 for the auxiliary electric motor 6 and for the controller 7 the internal combustion engine 2 and gives them to the facility 19 for the auxiliary electric motor 6 or the control unit 7 from, so that the auxiliary electric motor 6, the internal combustion engine 2 starts. Since at the start the internal combustion engine 2 not with the main electric motor 3 over the separating clutch 4 coupled, occurs at the output of the powertrain initially no torque change, in particular no torque dip on.

For further operation, the controller determines 1 after starting the internal combustion engine 2 a current speed of the main electric motor 3 , for which they use for example corresponding still stored data, corresponding data from the operating device 13 interrogate, or signals of a speed sensor to the main electric motor 3 can capture. By issuing appropriate signals to the internal combustion engine 2, ie the control unit 7 the internal combustion engine 2 , and the auxiliary electric motor 6 , more precisely, the operating equipment 19 for this, the auxiliary electric motor becomes 6 so controlled that the speeds of the internal combustion engine 2 and the main electric motor 3 be aligned with each other. Further, it forms clutch control signals for the clutch 4 and gives these to the clutch 4 , more precisely their operating equipment 12 off, on the back of the clutch 4 engages. It can be of a for the duration of the warm start of the engine 2 and in particular for the duration of the engagement largely constant speed on the side of the main electric motor 3 be assumed because the vehicle mass is relatively large and the ride comfort and the Radhaftung sets limits for the rate of change of speed in the drive train.

In this way needs as a clutch 4 only one disconnect clutch, but not to be used a starting clutch.

Next checks the controller 1 at least during operation of the internal combustion engine 2 constantly whether it should be switched off due to low speed and / or low load request.

In particular, it checks whether the current speed of the main electric motor 3 is less than a predetermined limit, the speed of the internal combustion engine 2 below which a trouble-free operation of the internal combustion engine is no longer expected. This speed may have been determined empirically, for example. If the speed is less than the limit, the controller generates 1 at least one clutch control signal for the clutch 4 , more precisely their operating equipment 12 , and gives this to the clutch 4 or the operating device 12 off, leaving the clutch 4 disengages. The drive now takes place solely with the main electric motor 3 while depending on the state of the energy storage 17 and 18 and the temperature of the internal combustion engine 2 for charging by means of the auxiliary electric motor 6 independent of the main electric motor 3 continue to operate or shut off. For this purpose, the control device checks 1 whether the energy storage 17 and 18 are sufficiently charged and the current temperature is above the minimum temperature. If both conditions are met, in the present example, the internal combustion engine 2 shut down, otherwise continue to operate.

To supply the electrical system 30 with power and / or for charging the additional energy storage 18 can the controller 1 the switching unit 20 and the facility 19 for the auxiliary electric motor 6 by formation and release of appropriate signals so drive that the auxiliary electric motor 6 as of the internal combustion engine 2 driven generator is connected and the additional energy storage 18 as well as the electrical system battery 17 during operation of the internal combustion engine 2 charges when the auxiliary electric motor 6 not for starting the internal combustion engine 2 and / or for synchronizing the rotational speeds of the internal combustion engine 2 and main electric motor 3 is controlled. This can always happen when the said condition is met, or in other embodiments only when certain control signals are present, for example those indicating that the supplemental energy storage 18 and / or the electrical system battery 17 have to be loaded.

Next checks the controller 1 During operation, the state of charge of the energy storage 21 whether it should be loaded. For this purpose, for example, the voltage of the energy storage 21 recorded and with a corresponding limit, which is the allowable minimum voltage of the energy store 21 be compared. Next, the operating state of the drive train is checked to see whether the charging of the energy storage is possible. For this purpose, for example, it can be checked whether the internal combustion engine 2 is operating at a speed above the limit value prescribed for its operation, a gear change, ie a shift back, is no longer possible or sensible and the disconnect clutch 4 closed is. If this is the case, forms the control device 1 a main electric motor signal and outputs this to the operating device 13 down, on the back of the facility 13 the main electric motor 3 as a generator for charging the energy storage 21 operates.

Finally, the control device 1 in case of failure of the main electric motor 3 and / or the facility 13 to run an emergency program for this, which allows the motor vehicle 31 to move even with the internal combustion engine 2 alone, although in the drive train no starting clutch is present.

For this purpose, the control device checks 1 permanently, whether a malfunction of the main electric motor 3 and / or the facility 13 is present. For this purpose, it can, for example, corresponding diagnostic signals from the operating device 13 capture and evaluate. When a malfunction is detected and the internal combustion engine 2 stands, she continues to check whether the clutch 4 is open. If this is not the case, the clutch will 4 by delivering appropriate signals to the clutch 4 open. Then the control device forms 1 corresponding signals for the operating device 19 for the auxiliary electric motor 6 and the controller 7 for the internal combustion engine 2 and gives them to the facility 19 and the controller 7 from. The internal combustion engine 2 is then by means of the auxiliary electric motor 6 without a query of the temperature of the internal combustion engine 2 started, which is possible because the clutch 4 is open. After successful start the controller checks 1 the state of the transmission 5 and applies to the transmission depending on the result of the test by delivering appropriate transmission signals 5 or its operating device 15 a gear suitable for emergency operation. Thereafter, the controller controls 1 by delivery of appropriate signals, the clutch 4 and about the facility 15 The gear 5 so on, that the torque from the engine 2 as gently as possible over the separating clutch 4 and the gearbox 5 by appropriate actuation of its clutches and brakes on the output 29 of the transmission 5 is transmitted.

Another preferred embodiment differs from the previously described embodiment in that the second voltage plane is missing. The auxiliary electric motor 6 is then via its inverter to the general electrical system 30 connected.

In yet another embodiment, it is possible to use the auxiliary electric motor 6 using a suitable voltage converter directly from the high voltage energy storage, ie the accumulator system 21 to dine.

In other embodiments, at least one of the operating devices and / or the control device in the control device 1 be integrated.

However, it is also possible that the control device is integrated in one of the operating devices or the control unit.

Yet another embodiment differs from the first embodiment in that a belt transmission is used in which the belt tension is exceeded by the control device 1 emitted signals is controllable. When operating as a starter belt tension is increased, reduced when operating as a generator.

Another, in 2 illustrated preferred embodiment differs from the first described embodiment in that instead of the belt gear, a gear transmission 28 is used. Instead of a starter for the internal combustion engine, which is designed by its construction also for a drive train with sole conventional combustion engine, now the auxiliary electric motor 6 attached, the connection between the starter and the internal combustion engine 2 via a starter pinion through the gear transmission 28 is replaced. All other components are unchanged, so that the same reference numerals are used for them and the explanations on the first embodiment also apply here accordingly.

The gear transmission 28 between the internal combustion engine 2 and the auxiliary electric motor 6 allows a slip-free transmission of torque between the internal combustion engine 2 and the auxiliary electric motor 6 and thus increases the efficiency of the powertrain.

Another preferred embodiment differs from the first embodiment in that for switching between charging the additional energy storage and the on-board battery, the in WO 02/066293 A1 is used, the content of which is hereby incorporated by reference in the description.

In yet another preferred embodiment, the auxiliary electric motor 6 on the clutch 4 facing side of the internal combustion engine 2 arranged, wherein the additional electric motor either directly to the flywheel 9 engages or by means of a Zugmittel- or friction gear, in particular a belt drive, or coupled by means of a gear transmission with this for the transmission of torques and rotational movements.

However, it is also possible on the same side a coupling with the output shaft 8th and not with the flywheel 9 ,

In yet another preferred embodiment, the flywheel is eliminated 9 , Its function or the corresponding moment of inertia can then be taken over by the clutch and / or the belt transmission, for which purpose they are to be interpreted accordingly.

Claims (29)

Drive train for a full hybrid drive for a motor vehicle (31) comprising an internal combustion engine (2) with an output shaft (8), a main electric motor (3), by means of which alone a predetermined power for moving the motor vehicle (31) can be generated from the stand, a clutch (4) by means of which the output shaft (8) is selectively connectable to the main electric motor (3), a transmission (5) coupled to the main electric motor (3), and an auxiliary electric motor (6) connected to the internal combustion engine (2) is connected and by means of which the internal combustion engine (2) at least at a current, a predetermined minimum temperature exceeding temperature of the internal combustion engine (2) can be started, characterized in that the main electric motor (3) is designed as a starter generator that the predetermined minimum temperature greater than 10 ° C, and that the mechanical power of the auxiliary electric motor is not sufficient to the internal combustion engine (2) zuverl to start SSIG when the operating temperature is below the minimum temperature. Drive train after Claim 1 in which the main electric motor (3) is coupled to the transmission (5) without a clutch. Drive train according to one of the preceding claims, wherein the transmission (5) is a converterless transmission. Drive train according to one of the preceding claims, wherein the transmission (5) comprises a planetary gear. Drive train according to one of the preceding claims, wherein the clutch (4) is a separating clutch. Drive train according to one of the preceding claims, wherein the auxiliary electric motor (6) is designed for operation with low voltage. Drive train according to one of the preceding claims, wherein the auxiliary electric motor (6) is designed as a starter-generator. Drive train according to one of the preceding claims, in which a Zugmittel- or friction gear (16) is provided, which couples the auxiliary electric motor (6) with the internal combustion engine (2). Powertrain after one of Claims 1 to 7 in which a gear transmission (28) is provided, which connects the auxiliary electric motor (6) with the internal combustion engine (2). Drive train after Claim 7 or after Claim 7 and one of the Claims 8 or 9 in which a device (19) is provided, by means of which the auxiliary electric motor (6) is connected to an electrical system (30) of the motor vehicle (31) for charging a vehicle electrical system battery (17). Drive train after Claim 7 or Claim 10 or after Claim 7 and one of the Claims 8 or 9 in which the auxiliary electric motor (6) is connected to an energy store (18) for fast storage of generated and discharged stored electrical energy. Drive train after Claim 11 in which the auxiliary electric motor (6) or an operating device (19) for the latter is connected to the energy store (18) via an electrically controllable changeover unit (20), in which the changeover unit (20) switches to the additional electric motor (6) in response to corresponding changeover signals. the operating device (19) connects to either the energy store (28) or an output to an on-board network (30), and in which the auxiliary electric motor (6) is designed so that when operated as a generator at a corresponding position of the electrical switching unit (20) can supply the electrical system (30) without an additional DC-DC converter. Powertrain after one of Claims 1 to 12 comprising a voltage converter (22) connected to an energy store (21) for supplying the main electric motor (3), the voltage supplied by the energy store to the Voltage of a given electrical system (30) of the motor vehicle (31) converts. Method for operating a full hybrid drive with a drive train according to one of Claims 1 to 13 in which temperature signals representing a temperature of the internal combustion engine (2) are detected, in which when the internal combustion engine (2), working main electric motor (3), a detected temperature exceeds a predetermined minimum temperature greater than 10 ° C, and at Fulfillment of at least one further operating condition for the drive train control signals for an operating device (19) for the auxiliary electric motor (6) are formed and delivered to this, so that the auxiliary electric motor (6) starts the internal combustion engine (2), and in which for starting the internal combustion engine ( 2) are formed and delivered at an operating temperature below the minimum temperature to which the clutch (4) engages, it is checked whether the transmission (5) is in an idling or neutral position, if this is not the case, generates a transmission signal and is delivered to the gearbox (5) is switched to an idle or neutral position, and dana Control signals for starting the internal combustion engine (2) are formed and delivered by the main electric motor (3). Method according to Claim 14 in which, after the starting of the internal combustion engine (2), a current rotational speed of the main electric motor (3) is determined, and the internal combustion engine (2) and / or the auxiliary electric motor (6) is triggered by output of appropriate signals such that the rotational speed of the internal combustion engine (2 ) and the main electric motor (3) are made to be equal to each other and clutch control signals for the clutch (4) are formed and delivered thereto, to which the clutch (4) engages. Method according to Claim 14 or 15 in which a check is made as to whether start-up is desired and, if so, main electric motor and / or clutch control signals are formed and delivered so that the clutch (4) is disengaged or disengaged and an operating device ( 13) for the main electric motor (3) drives it for starting alone with the main electric motor (3). Method according to one of Claims 14 to 16 in which it is checked whether the current rotational speed of the main electric motor (3) and / or a desired torque are smaller than predetermined limit values, and, if this is satisfied, a clutch control signal is formed and delivered so that the clutch (4) disengages. Method according to one of Claims 14 to 17 in which it is checked whether there is a malfunction of the main electric motor (3) or an operating device (13) for this, and, if this is the case and the internal combustion engine (2), by supplying corresponding signals to an operating device (18) for the auxiliary electric motor (6) and to a control unit (7) for the internal combustion engine (2) the internal combustion engine (2) started and a clutch control signal for engaging the clutch (4) is formed and delivered to the clutch (4). Method according to one of Claims 14 to 18 in which the additional electric motor (6) is a starter-generator and is switched as a function of at least one further control signal or always as a generator driven by the internal combustion engine (2), if the auxiliary electric motor (6) is not used for starting the internal combustion engine (2). and / or for synchronizing the rotational speeds of the internal combustion engine (2) and main electric motor (3) is driven. Method according to one of Claims 14 to 19 in which the main electric motor (3) is designed as a starter-generator and in which it is checked whether an energy store (21) for supplying the main electric motor (3) is to be charged, and formed in response to the result of the test, a main electric motor signal and is discharged, on the back of the main electric motor (3) is operated as a generator for charging the energy storage device (21). Control device for controlling a full hybrid drive with a drive train according to one of Claims 1 to 13 having at least one output for outputting main electric motor signals to an operating device (13) for operating the main electric motor (3), for outputting clutch control signals for disengaging or engaging the clutch (4), for delivering auxiliary electric motor signals to an operating device ( 19) for the auxiliary electric motor (6), for outputting signals to a control unit (7) for the internal combustion engine and for outputting gear signals to the gearbox (5) and at least one input for receiving temperature signals indicative of a temperature of the internal combustion engine (2) reproduce, and is further adapted to detect temperature signals and when the internal combustion engine (2), working main electric motor (3), and a detected temperature which exceeds a predetermined minimum temperature greater than 10 ° C, and at least one fulfillment of another Operating condition for the powertrain Control signals for an operating device (19) for to form the auxiliary electric motor (6) and deliver to the auxiliary electric motor (6), the internal combustion engine (2), and which is further adapted to be used to start the internal combustion engine (2) at a Operating temperature below the minimum temperature when the main electric motor (3) forms and releases clutch control signals to which the clutch (4) engages, checks whether the transmission (5) is in an idling or neutral position and, if this is not the case, generates and outputs a transmission signal to which the transmission (5) is switched to an idling or neutral position and then control signals for starting the internal combustion engine (2) by the main electric motor (3) forms and outputs. Control device after Claim 21 , which is further adapted to that after starting the internal combustion engine (2) determines a current speed of the main electric motor (3), by outputting corresponding signals, the internal combustion engine (2) and / or the auxiliary electric motor (6) so controls that the speed of the internal combustion engine (2) and the main electric motor (3) are matched to each other, and clutch control signals for the clutch (4) forms and outputs to this, to which the clutch (4) engages. Control device after Claim 21 or Claim 22 , which is further adapted to check whether a start-up is desired and, if so, to form and deliver main electric motor and / or clutch control signals such that the clutch (4) is disengaged or disengaged and the operating device (13) for the main electric motor (3) drives it for starting only with the main electric motor (3). Control device according to one of Claims 21 to 23 further adapted to check whether the current speed of the main electric motor (3) and / or a desired torque are less than predetermined limits, and, if satisfied, form and output a clutch control signal such that the clutch ( 4) disengages. Control device according to one of Claims 21 to 24 , which is further adapted to check whether there is a malfunction of the main electric motor (3) or the operating device (13) for this, and, if this is the case and the internal combustion engine (2), by supplying corresponding signals to the Operating device (19) for the auxiliary electric motor (6) and to the control unit (7) for the internal combustion engine (2), the internal combustion engine (2) starts, and at least one clutch control signal for engaging the clutch (4) forms and outputs. Control device according to one of Claims 21 to 25 , which is further configured so that the then designed as a starter generator auxiliary electric motor (6) is connected in response to at least one further control signal or always as driven by the internal combustion engine (2) generator when the auxiliary electric motor (6) not to start the internal combustion engine (2) and / or for synchronizing the rotational speeds of the internal combustion engine (2) and main electric motor (3) is driven. Control device according to one of Claims 21 to 26 , which is further adapted to check whether an energy storage (21) to supply the main electric motor (3) is to be loaded, and depending on the result of the test a main electric motor signal forms and outputs, then out as Starter-generator trained main electric motor (3) is operated as a generator for charging the energy storage device (21). Computer program for one with a powertrain after one of Claims 1 to 13 Data processing device (1) to be connected to a processor (23) comprising instructions, in the execution of which the processor (23) and / or the data processing device (1) execute the operating method according to one of Claims 14 to 20 performs. Storage medium with a computer program stored on it Claim 28 ,

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