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AssigneeZF Friedrichshafen AG
InventorsJohannes Kaltenbach, Stefan Wallner
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The invention relates to a method and device for controlling a creep operation of a vehicle with a hybrid drive (1), comprising a parallel hybrid drivetrain (2), with an internal combustion engine (3), at least one electric motor (5), a first switching element (4) in the form of a friction element between the internal combustion engine (3) and the electric motor (5), a gearbox (7), an output (26) and a second switching element (6) arranged between the electric motor (5) and the output (26). According to the invention, a simple, effective and component-friendly continuous creeping can be achieved without additional constructional or economic costs can be achieved, wherein the creeping operation is carried out with the internal combustion engine (3) running and both switching elements (4,6) simultaneously operating with slip, wherein the total operating power required to generate a required creeping torque is variably distributed over both switching elements (4, 6).
A method for controlling a creeping operation of a vehicle with a hybrid drive, with a parallel hybrid drive train, comprising an internal combustion engine, at least one electric motor, a first shifting component designed as a frictional component that is arranged between the combustion engine and the electric motor, a transmission, an output and a second shifting component designed as a frictional component that is arranged between the electric motor and the output, characterized in that to realize the creeping operation with running internal combustion engine, the two shifting components are simultaneously operated in slip operation, with an overall friction output that is required to produce a desired creeping moment is variably distributed to the two shifting components, wherein the distribution of the overall friction output to the two shifting components is performed using a rotational speed control of the electric motor, by means of which the power dissipating moment of the shifting components, which are correlated with the individual frictional moments, are set, with the electrical motor speed (nEM) is varied in a speed range between a transmission input speed (nGE) as a lower limit, and a combustible engine speed (nVM) as an upper limit.
An apparatus for controlling a creeping operation of a vehicle with a hybrid drive, with a parallel hybrid drive train, comprising an internal combustion engine, at least one electric motor, a first shifting component designed as a frictional component that is arranged between the combustion engine and the electric motor, a transmission, an output and a second shifting component designed as a frictional component that is arranged between the electric motor and the output, characterized in that a control means to realize the creeping operation with running internal combustion engine are provided, by means of which the two shifting components are simultaneously operated in slip operation, with an overall friction output that is required to produce a desired creeping moment is variably distributed to the two shifting components, wherein the distribution of the overall friction output to the two shifting components is performed using a rotational speed control of the electric motor, by means of which the power dissipating moment of the shifting components, which are correlated with the individual frictional moments, are set, with the electrical motor speed (nEM) is varied in a speed range between a transmission input speed (nGE) as a lower limit, and a combustible engine speed (nVM) as an upper limit.
Dependencies are inferred from the claim text.
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Control systems specially adapted for hybrid vehicles: control strategies involving selection of hybrid configuration, e.g. selection between…
Characterised by the driveline clutches: actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
Characterised by apparatus, components or means specially adapted for HEVs: characterised by the assembly or relative disposition of components
Characterised by the architecture of the hybrid electric vehicle: parallel type
About 3 years 6 months of term left · ends 28 Apr 2030 (estimated)
This application is a filing under 35 U.S.C. §371 of International Patent Application PCT/EP2008/066572, filed Dec. 2, 2008, which claims priority to German Application No. 10 2007 055 825.4, filed Dec. 17, 2007, each of which is incorporated by reference herein in its entirety.
The invention relates to a method and apparatus for controlling a creeping operation of a vehicle with a hybrid drive.
Hybrid drives gain in importance in the vehicle manufacturing because of their potential to cut emissions and energy consumption. Such cars have various power sources, with combinations of internal-combustion engine and electric motors being particularly advantageous, because they can utilize, on the one hand, the range and performance advantages of internal-combustion engines and, on the other, the flexible applications of electrical machines as a sole or auxiliary power source or as a starter generator to produce electricity and ensure recuperation.
To illustrate the invention, a drawing is included in the description of an embodiment. This shows
FIG. 1 shows a schematic representation of a hybrid drive of a vehicle for the implementation of an inventive method for controlling a creeping operation, and
FIG. 2 shows a speed chart for friction output distribution to two clutches during the creeping operation.
FIG. 1 represents a diagram of a hybrid vehicle drive 1 with a parallel hybrid power train 2, as it can be used, for example, in a commercial vehicle (truck, bus, special vehicle). The drive train 2 has an internal combustion engine 3, for example, a diesel engine with a crankshaft 24, which can be connected to an electric motor 5 via a shifting component 4 that is designed as a friction clutch. The electric machine 5 can, in turn, be coupled—via a second shifting component 6 that is designed as a friction clutch—with a transmission input 27 of the transmission 7. The function of the second shifting component 6 can be assumed, as already mentioned above, by (not shown) coupling components arranged inside the transmission, in particular one or more clutches and/or switching brakes of a suitably designed transmission, for example, a tri-element planetary gear train. The transmission 7 can be followed, as indicated in FIG. 1, by a non-described power take-off (PTO) 8 as a subordinate drive technology. Over a drive 26 and a differential output 9, an output torque of the hybrid drive can be transmitted to a drive axle 10 and, though this, then forwarded to the drive wheels 11.
Depending on the operating situation, the electric machine 5 may be operated as an electric drive unit or as a generator. For this purpose, it is connected to a converter 12, which is controlled by an inverter control unit 13. By means of the inverter 12, the electrical machine 5 is connected with an electric energy storage drive 14, for example, a 340V high-voltage battery (supercaps are also possible). When in its motor operation, the electric motor is fed energy from the energy storage device 14. In its generator mode, i.e., when driving through the combustion engine 3 and/or in the recuperation operation, the energy storage device 14 is being charged by the electric motor 5. Furthermore, the electric motor 5 acts as an integrated starter generator (ISG) to start the combustion engine 3. The high-voltage circuit of the energy storage device 14 and/or the connected control units are connected to a vehicle electrical system 16 (24V or 12V) via a bi-directional DC/DC 15. The energy storage device 14 is monitored and controlled by a battery management system (BMS) 17 with respect to its state of charge (SOC). The DC 15 is controlled by a DC-control unit 18. Moreover, a control unit 19 for unspecified brake control functions, in particular an anti-lock brake system (ABS) or an electronic braking system (EBS) and another control unit 20 for an electronic diesel control (EDC) of the provided combustion engine 3 designed, for example, as a diesel engine. The various above-mentioned control units can also be integrated at least in part, in a single a control unit.
Furthermore, an integrated control device 21 is provided, which integrates a transmission control unit (TCU), a hybrid control unit (HCU) and various operational functions in the form of electronic control and/or regulation programs. According to the invention, to the control device 21 there are assigned control means 25 to control the shifting components 4 and 6 for their slip mode. For this purpose, the control means 25 are designed to that they act in coordination with the control device 21, which also controls the operation of the electrical machine 5, in the regulation of an inventive creeping operation with two shifting components 4, 6 in the slip operation and speed control of electric machinery 5. A central strategy unit 22 is provided to control and switch the possible drive modes of the hybrid drive, which is advantageously connected via a data bus (e.g., CAN) 23 with the control device 21 and the control unit 25 and the other relevant control devices 13, 17, 18, 19.