DE102006012788A1 - Hybrid drive`s torque distributing method for use in e.g. hybrid electric vehicle, involves determining torque requested by driver, where provisional torque of internal combustion engine is determined from requested torque - Google Patents

Abstract

The method involves requesting a torque (16) of a hybrid drive of a vehicle by a driver. The torque requested by the driver is determined. The torque is received for determining a provisional torque of an electric motor (2). A provisional torque of an internal combustion engine (3) is determined from the requested torque. A torque (21) for the electric motor of the hybrid drive is pre-computed from the requested torque (16). An alignment (24) between the torque (21) and a torque (23) is calculated. An independent claim is also included for a hybrid drive of a vehicle.

Description

The The present invention relates to a torque distribution method by means of a hybrid drive of a vehicle and a hybrid drive of a Vehicle with at least one electric motor and an internal combustion engine.

hybrid drives a vehicle usually have at least two drive sources on. As a rule, it is an internal combustion engine and at least one electric motor. A torque transmission from internal combustion engine and electric motor is usually dependent on of different driving conditions, states of charge a battery as well as a torque distribution strategy various torque requirements of the driver, the state of charge the battery, the vehicle speed, an engine speed like also in dependence adjusted by emissions. One way of dividing the Determining torque is a percentage distribution the torques over a Map to determine. For example, in the map next to the speed of the internal combustion engine a desired Torque of the driver in particular depending on the drive and the Charge state of the battery to be deposited as an input. As possible Result of the map can be a factor or a percentage to be taken with the maximum torque of the electric motor is multiplied to a desired one Share of an electric motor torque to get. Hereinafter various torque distribution strategies are presented, as they emerge from the prior art.

For example, goes from the DE 103 14 396 A1 a method and apparatus for torque distribution in a hybrid electric vehicle. In this case, a torque distribution is achieved via a position detection of the accelerator pedal. In a first area, the vehicle is driven only by the electric motor. When a limit is exceeded, the internal combustion engine is switched on. In this way, a particularly pleasant driving is to be made possible. From the DE 196 32 855 A1 A hybrid vehicle emerges to prevent a vehicle engine from spinning. In the state of the art resulting from this document, it is assumed that operating states can occur in which an output torque of an internal combustion engine increases so much that an electric motor can no longer apply a corresponding reaction torque. To avoid this, a control system is described in which an output torque of the internal combustion engine via a throttle position and a corresponding map is determined. From this, an input torque of an automatic transmission and a torque of the electric motor are calculated. A resulting output torque is then determined via the transmission ratio of the automatic transmission and the already determined input torque. This results in an engine speed, which is used to deduce the necessary engine torque. From the DE 198 31 487 C1 Again, a completely different strategy for determining a torque in a hybrid drive emerges. As can be seen from the description there is a distinction between two extreme operating strategies, according to the former is focused only on an operating point in which the internal combustion engine and the electric motor have the best possible efficiency, while according to the other operating strategy, the internal combustion engine is operated continuously and on the Required power the engine torque or electric motor torque is determined. From this document, a method for operating a hybrid drive is apparent, which can incorporate an influence of the distance in order to split based on this, the switching on and off and thus the torque between internal combustion engine and electric motor. From the DE 10 2004 046 194 A1 however, another hybrid vehicle controller emerges. This utilizes an accounting for a battery used to drive the internal combustion engine and the electric motor depending on the state of charge at an operating point, which is selected as a function of fuel economy based on the determined state of charge and recourse to one or more maps.

The The strategies described above are common to a desired torque distribution which, however, from the final achieved actual Torque distribution may differ.

task The present invention is in consideration of current conditions Torque-emitting units apply a required torque to be able to without too much deviation from the detected operating state to get the aggregates.

These Task is using a torque distribution method with the features of claim 1 and with a hybrid drive of a vehicle with the features of claim 14 solved. Advantageous developments and embodiments are specified in the respective subclaims.

• a) zur Bestimmung eines vorläufigen Drehmomentes eines Elektromotors,
• b) zur Bestimmung eines vorläufigen Drehmomentes einer Brennkraftmaschine, und
• c) zur Bestimmung eines anzufordernden Drehmomentes des Elektromotors

in eine jeweilige Berechnung ein.It is proposed a torque distribution method by means of a hybrid drive of a vehicle, in which a ange of a driver requested torque is absorbed. The requested torque goes

• a) for determining a preliminary torque of an electric motor,
• b) for determining a preliminary torque of an internal combustion engine, and
• c) for determining a torque to be requested of the electric motor

into a respective calculation.

The Use of the requested torque not only in a single, simple further processing, but in the determination of various Parameter for determining a total torque allows a special fast determination of a distribution of the necessary torque on the available standing units of the hybrid drive. Preferably, the Hybrid drive an internal combustion engine and at least one Electric motor on. Instead of or in addition to the internal combustion engine can also be a fuel cell drive or another, a torque generating device can be used. These can, for example, via a or a plurality of transmissions, preferably planetary transmissions, and / or clutches interconnected with each other. Preferably, it is the hybrid drive with a parallel hybrid drive. It can, however Other embodiments of hybrid drives are used, to apply the proposed torque distribution method can. By way of example, but not conclusively, this is the case in the above State of the art cited different hybrid systems and their different configurations in the context of this disclosure.

The Determination of a provisional Torque of the electric motor allows a first value of the To set torque, but not yet with the later indeed must match the torque requested by the electric motor. Much more allows the determination of the provisional Torque the opportunity as part of a torque distribution strategy, a first calculation make and be able to specify. The Determination of a provisional Torque of the internal combustion engine allows, with this value finally the To determine torque to be requested by the internal combustion engine can. By first provisional Torques are calculated by electric motor and internal combustion engine, can be ensured that via a subsequent reconciliation the values can use an optimization. Otherwise, a would Splitting the torques corresponding to the requested torque to the aggregates on the basis of one or more maps, However, without, however, the special features of the vehicle, the currently available, consideration would be taken. The use of the requested torque in the determination of the to be requested torque of the electric motor, that is that torque, that actually From the electric motor is to afford a control of the division. These allowed a multiple review of the actual torque options be able to provide for the aggregates in the calculation without it delays in the determination of the finally to be requested torques of internal combustion engine and electric motor comes.

Prefers it is when the requested torque is parallel in the steps a), b) and c) received. In this way, a parallel processing for the determination of the provisional Torques accompanied at the same time with a review of the resulting Values in the end to be set to be requested torque of the electric motor as also the internal combustion engine. In particular, this allows a review of the indeed existing torque of the internal combustion engine under consideration of the provisional Torque of the internal combustion engine, the former value in the Determination of the actual to be requested torque of the electric motor received. The electric motor is thus used, not by the internal combustion engine available as part of a torque distribution strategy Compensate torques. When calculating the torques can in determining the preliminary torques in particular a map-related calculation by a torque distribution strategy respectively. By the subsequent review of actual However, conditions ensure that the driver requested torque indeed also delivered.

A Embodiment of the torque distribution method provides that after an initial review of the requested torque is determined whether the electric motor at all capable of doing so within the torque distribution strategy fixed provisional Torque at all to deliver. Will this not be possible be, because, for example, a state of charge of the battery is not is sufficient, either only with the maximum possible torque of the electric motor the calculation continues. However, there is also the possibility that upon detection of an excess a maximum value of the torque of the electric motor by fixing a preliminary one Torque a repeated determination of a provisional torque for the electric motor over the Torque distribution strategy is done.

Furthermore, a further education of the Torque distribution method, that in the determination of the torque to be requested by the electric motor also a check of the actual available torque of the electric motor is carried out in advance. If it is found that the determined value for a torque request from the electric motor exceeds a maximum available value, this information can be returned to the torque distribution strategy. Then, for example, a new preliminary torque value for the electric motor is determined with which the calculation can be run again based on the torque requested by the driver. In this way it is ensured that the torque distribution strategy ultimately generates a distribution of the torque to be requested between the electric motor and the internal combustion engine, which is actually executable.

• – Es wird das von einem Fahrer angeforderte Drehmoment bestimmt,
• – ein erstes Drehmoment für zumindest den einen Elektromotor des Hybridsystems ausgehend vom angeforderten Drehmoment wird vorberechnet,
• – es erfolgt eine Überprüfung, ob das erste Drehmoment vom Elektromotor zur Verfügung gestellt werden kann, wobei ein vom Elektromotor zur Verfügung stehendes zweites Drehmoment ermittelt wird,
• – es erfolgt ein erster Abgleich zwischen dem ersten und dem zweiten Drehmoment,
• – auf Basis des angeforderten Drehmomentes und eines Ergebnisses des Abgleichs wird ein gewünschtes drittes Drehmoment berechnet, das eine Verbrennungskraftmaschine zur Verfügung stellen soll,
• – ein zweiter Abgleich erfolgt zwischen dem dritten Drehmoment und einem tatsächlich vorhandenen Drehmoment der Verbrennungskraftmaschine,
• – auf Basis des Ergebnisses des zweiten Abgleichs und des angeforderten Drehmomentes wird unter Heranziehung des zweiten Drehmomentes ein einzustellendes Elektromotor-Drehmoment ermittelt, und
• – das Elektromotor-Drehmoment und das aus dem zweiten Abgleich ermittelte, von der Verbrennungskraftmaschine zur Verfügung gestellte Drehmoment werden miteinander gekoppelt.

Another embodiment of a torque distribution method provides the following steps:

• - It determines the torque required by a driver,
• A first torque for at least one electric motor of the hybrid system based on the requested torque is pre-calculated,
• A check is made as to whether the first torque can be provided by the electric motor, whereby a second torque available from the electric motor is determined,
• A first comparison is made between the first and the second torque,
• On the basis of the requested torque and a result of the adjustment, a desired third torque which is to provide an internal combustion engine is calculated,
• A second adjustment takes place between the third torque and an actually existing torque of the internal combustion engine,
• Based on the result of the second adjustment and the requested torque, an electric motor torque to be set is determined using the second torque, and
• - The electric motor torque and the determined from the second balance, provided by the internal combustion engine torque are coupled together.

in this connection is provided that uses a torque distribution strategy is at least one from the driver's requested torque first value of a preliminary Determine torque. Preferably, the torque distribution strategy determines the provisional Torque of the electric motor firmly. For this purpose, for example, is provided that, in a control device, in particular in a control unit, the torque distribution strategy is deposited. The control device is supplied with parameters the at least one voltage state of a battery, a vehicle speed and characterize a rotational speed of the internal combustion engine. From these as well as from additional other incoming parameters, in particular from parameters such they emerge from the above known prior art and to which reference is made in the context of this disclosure, the Control device according to its own specifications, for example an efficiency maximization, a fuel minimization, a Emission minimization or any other specialization accordingly at least one, if not more, initial values for a subsequent calculation with further use of the requested torque from the driver form. It is preferred if the requested torque is parallel for determining a predetermined first and a predetermined third torque is used.

Especially in a parallel hybrid drive is provided that at least two electric motors the torque determined in the first compensation to work together. There is a possibility that the two electric motors either each provide a same torque contribution. However, it may also be appropriate that different torques provided by the existing electric motors. Preferably provides the torque distribution method that at two or more electric motors will be checked first, whether a single electric motor determined in the first compensation Can provide torque before dividing a to be provided Torque occurs on several electric motors. For example is envisaged that when using two or more electric motors to provide the torque determined in the first compensation below consideration the respective efficiencies of the electric motors torque distribution takes place on the individual electric motors. This can be ensured that, for example, possible losses are minimized.

Furthermore, the torque distribution method may provide that in at least one operating point, the requested torque is provided by the electric motor and the internal combustion engine alone. This can be the case, in particular, at operating points where sufficient torque generation can be ensured via the internal combustion engine. In particular, for this purpose, the torque distribution strategy can have a distinction as to when the torque is only delivered by the electric motor and when only by the internal combustion engine should be finished.

A Continuing training provides that the torque distribution strategy is activated only when based on the requested torque It is clear that this is an operating condition, the use of a makes the electric motor inevitable. This can, for example, in a high acceleration phase, in a high-speed phase as well as during a low vehicle speed or even insufficient charging of the internal combustion engine, for example by a turbocharger running at too low a compression ratio respectively.

For example it is envisaged that, in the case of a determination of an inadequate resulting torque to cover the requested torque from the first adjustment and the second adjustment at least one Recalculation of the resulting torque is done. It can be provided be that from a difference of the requested torque and the result of the first adjustment determines the third torque becomes. It can also be provided that from a difference from the requested torque and from the result of the second Adjustment the electric motor torque is determined. The calculation in the form of a difference allows a particularly fast Determining the respective values, to finally about the necessary electric motor torque to get. Dependent on For example, one of the values determined is that a Engine control a corresponding injection of the internal combustion engine controls.

Becomes the torque distribution method provided in a hybrid drive, in which an electric motor is arranged behind a transmission, so Provide that the requested torque of a gear ratio is adjusted.

According to one Another idea of the invention is a hybrid drive of a vehicle with at least one electric motor and an internal combustion engine to disposal posed. An embodiment of the hybrid drive or an arrangement the one or more electric motors can, as already stated above, accordingly the above-mentioned prior art, to the extent in this respect the disclosure is referenced. Furthermore, at least one control unit, a Torque distribution strategy and a sensor for determination a torque request of a driver of the vehicle provided. The control unit has at least one input via which the torque request the driver, a momentary torque of the internal combustion engine and one or more provisional Enter torques according to the torque distribution strategy. The control unit has at least one output via which at least one of the Internal combustion engine to be requested torque and one of the Electric motor request torque to go out. The control unit points a compensation calculation between the available torque of the internal combustion engine and the provisional torque the internal combustion engine by adjusting the of the electric motor to be requested torque deposited.

Especially can with the hybrid engine of the vehicle with the connected Devices are running a torque distribution method, as stated above.

Preferably is the control unit with an engine control unit via a coupled to the serial data bus, wherein the engine control unit has a functionality for calculation implemented a current torque of the internal combustion engine whose value is provided to the controller. Such functionality is provided for example by the engine control unit DCM 3.1 from Delphi. The control unit, by means of the torque distribution is done, for example, part a hybrid control unit, a so-called HCU - hybrid control unit, be. It However, there is also the possibility that the controller as a separate control unit is housed in the vehicle. In addition, there is the possibility that the controller Part of the engine control unit is.

According to one Embodiment of the hybrid engine is provided that the internal combustion engine and the electric motor are arranged in a parallel circuit. For example, it can be provided that the internal combustion engine and the electric motor have separate waves separated from each other, wherein the electric motor on a drive shaft or on a wheel of the vehicle is arranged. In particular, it can be provided that at least two or four electric motors are provided in the Trap of the latter assigned to each individual wheel of the vehicle are. A development has at least one clutch, via whose activity from a parallel operation to another operation of internal combustion engine and Electric motor can be changed. For example, this can be be a serial operation.

Further advantageous embodiments and further developments are explained in more detail with reference to the following drawings. However, the resulting individual features are not limited to the individual embodiments. Rather, these features may be described above with individual features or features of others Embodiments are connected to further embodiments. Show it:

1 a schematic partial view of a vehicle with a hybrid drive and associated units for determining a requested torque and a distribution of torque to at least one electric motor and an internal combustion engine and

2 an exemplary representation of a possible torque distribution method.

1 shows a schematic view of a hybrid drive 1 of a vehicle. The hybrid drive 1 has at least one electric motor 2 and an internal combustion engine 3 on. About a gearbox 4 For example, the torque provided by each of the two units can be applied to a drive train 5 to provide. There is also an accelerator pedal 6 indicated, which with a schematically indicated sensors 7 connected is. About the sensors 7 is a requested torque on the position of the accelerator pedal 6 determined and sent to a control device 8th transfer. The control device 8th is for example a separately arranged control unit 9 , This is via a serial data bus 10 with an engine control unit 11 , an electric motor control unit 12 and for example other controllers 13 connected. The control unit 13 For example, the controller may be a circuit. The control device 8th has a torque distribution strategy deposited. About an entrance 14 and an exit 15 can from the controller 8th corresponding signals via the serial data bus 10 to the engine control unit 11 as well as the electric motor control unit 12 be passed on. For example, the electric control unit 12 with the electric motor 2 , A non-illustrated battery and a temperature monitor the E lektromotors 2 connected. In particular, the electric motor 2 also as a generator in the context of the hybrid drive 1 be used. The control device 8th is capable of generating a preliminary torque for the electric motor from the requested torque of the driver via the stored torque distribution strategy 2 to determine. Furthermore, there is the possibility that the control device 8th is able to determine a preliminary torque of an internal combustion engine. Preferably, the control device 8th additionally capable of also determining a torque of the electric motor to be requested, namely the electric motor torque. For this purpose, it can for example each on the electric motor control unit 12 or the engine control unit 11 To fall back on. By way of example, there is the possibility of experiencing the torque values that are possible at the present time and of incorporating them into the respective torque distribution.

2 shows an exemplary embodiment of a possibility of a torque distribution method, as for example with the hybrid drive 1 is executable. The following are the same or similar elements 1 in 2 provided with the same reference number. About the sensors 7 becomes the requested torque 16 to a torque distribution strategy to a first computing element 18 and to a second computing element 19 guided. The torque distribution strategy 17 receives parameters 20 of various devices, sensors, control devices and similar devices. This may be, for example, a battery state of charge, a vehicle speed, a rotational speed of a crankshaft of the internal combustion engine, a temperature of a battery, for example, or other predictions necessary for a design of the torque distribution strategy. In addition to actual states, this can also include state variables that are considered over time, such as wear and the like. It is also possible that parameters are included, as they are also in the above-known prior art in the torque distribution strategies and referred to in the context of this disclosure in this regard. The torque distribution strategy 17 is capable of using the supplied parameters 20 and from the requested torque 16 a first torque 21 to determine that from the electric motor as part of a breakdown of the requested torque 16 to be requested. A review 22 compares the first torque 21 with a second torque 23 which characterizes the torque that is available from the electric motor at the moment. Over the first reconciliation in the check 24 becomes a result of the check to the first computation element 18 to hand over. There is also the requested torque 16 one. The first computing element 18 is able to make a difference from the result 25 the first match 24 and the requested torque 16 to investigate. For example, the requested torque 16 as a positive value in the first calculation element 18 be deposited while the result 25 as a negative value. After formation of the absolute value results in a desired third torque 26 which is to provide the internal combustion engine. About a second review 27 For example, it can be determined if the desired third torque 26 can be made available at all. After such a second adjustment 27 between the third torque 26 and the actually existing torque of the internal combustion engine results in a torque to be requested by the internal combustion engine 28 , This will, for example, the engine control 11 to hand over. The engine control 11 operated accordingly the requested torque 28 the internal combustion engine 3 , For example, a fuel injection, a fuel injection mass flow, a valve opening or closing or other engine measures on the part of the engine control 11 respectively. Furthermore, in this schematically illustrated embodiment of a torque distribution method, the engine control 11 capable of the current torque 29 the internal combustion engine 3 to the second computing element 19 transferred to. In the second computing element 19 also goes the requested torque 16 one. The second computing element 19 can as well as the first computing element 18 be designed and work. This means that a difference is again determined from the values received. The result will again be a third review 30 subjected to the resulting desired torque of the electric motor with the second torque 23 , which is actually available from the electric motor, is brought into balance. This results in the requested electric motor torque 31 , This becomes, for example, the electric motor control unit 12 pass, that according to the electric motor 2 actuated. The torque values used in these torque distribution methods shown schematically and implemented by way of example can be represented directly as torques as well as parameters characterizing them by torque. In addition to the elements shown additional elements may be inserted, which allow, for example, repeated steps, in particular checks. In particular, this is off 2 not to limit the procedure but only as an example.

Claims (19)

Torque distribution method using a hybrid drive ( 1 ) of a vehicle with a torque requested by a driver ( 16 ), which a) for determining a preliminary torque of an electric motor ( 2 ), b) for determining a preliminary torque of an internal combustion engine ( 3 ), and c) for determining a torque of the electric motor to be requested ( 2 ) is included in a respective calculation. Torque distribution method according to claim 1, characterized in that the requested torque ( 16 ) enters into steps a), b) and c) in parallel. A torque distribution method according to claim 1 or 2, comprising the following steps, wherein - the torque requested by a driver ( 16 ), - a first torque ( 21 ) for at least the electric motor ( 2 ) of the hybrid drive ( 1 ) based on the requested torque ( 16 ), - a first comparison ( 24 ) between the first (21) and a second (23) torque, wherein a check ( 22 ), whether the first torque ( 21 ) from the electric motor ( 2 ) and one of the electric motor ( 2 ) available second torque ( 23 ), - on the basis of the requested torque ( 16 ) and a result of the reconciliation ( 24 ) a desired third torque ( 26 ) calculating the internal combustion engine ( 3 ), - a second comparison between the third torque ( 3 ) and an actual torque of the internal combustion engine takes place, - on the basis of the result of the second adjustment and the requested torque ( 16 ) using the second torque ( 24 ) an electric motor torque to be adjusted ( 31 ), and - the electric motor torque ( 31 ) and the second balance determined by the internal combustion engine ( 3 ) provided torque are coupled together. Torque distribution method according to claim 3, characterized in that the requested torque ( 16 ) parallel to the determination of a predetermined first ( 21 ) and a predetermined third ( 26 ) Torque is used. Torque distribution method according to one of the preceding claims, characterized in that one in a control device ( 8th ) stored torque distribution strategy ( 17 ) with parameters ( 20 ), which characterize at least one voltage state of a battery, a vehicle speed and a rotational speed of the internal combustion engine. Torque distribution method according to one of the preceding claims 3 to 5, characterized in that at least two electric motors in the first alignment ( 24 ) provide certain torque together. Torque distribution method according to one of the preceding claims 3 to 6, characterized in that in two or more electric motors first checked, whether a single electric motor determines the torque determined in the first adjustment can provide before an allocation of a torque to be provided takes place on several electric motors. Torque distribution method after a of the preceding claims 3 to 7, characterized in that when using two or more electric motors for providing the torque determined in the first adjustment takes into account the respective efficiencies of the electric motors, a torque distribution to the individual electric motors. Torque distribution method according to one of the preceding claims, characterized in that in at least one operating point the requested torque from the electric motor ( 2 ) or of the internal combustion engine ( 3 ) is delivered alone. Torque distribution method according to one of the preceding claims 3 to 9, characterized in that when determining a non-sufficient, resulting torque to cover the requested torque ( 16 ) from the first comparison ( 24 ) and the second adjustment takes place at least a recalculation of the resulting torque. Torque distribution method according to one of the preceding claims 3 to 10, characterized in that from a difference of the requested torque ( 16 ) and the result of the first reconciliation ( 24 ) the third torque ( 26 ) is determined. Torque distribution method according to one of the preceding claims 3 to 11, characterized in that from a difference of the requested torque ( 16 ) and from the result of the second adjustment, the electric motor torque ( 31 ) is determined. Torque distribution method according to one of the preceding claims, characterized in that in an electric motor arranged behind a transmission, the requested torque ( 16 ) is adapted to a transmission ratio. Hybrid drive ( 1 ) of a vehicle with at least one electric motor ( 2 ) and an internal combustion engine ( 3 ), with at least one control unit ( 9 ), with a torque distribution strategy ( 17 ) and with a sensor system ( 7 ) for determining a torque request of a driver of the vehicle, wherein the control unit ( 9 ) at least one input ( 14 ), over which the torque request of the driver, a momentary torque of the internal combustion engine and the electric motor ( 2 ) and preferably one or more provisional torques according to the torque distribution strategy ( 17 ), and wherein the control unit ( 9 ) at least one output ( 15 ), via which at least one of the internal combustion engine ( 3 ) torque to be requested and one of the electric motor ( 2 ) torque to be requested, the control unit ( 9 ) a compensation calculation between an available torque of the internal combustion engine ( 3 ) and the preliminary torque from the internal combustion engine ( 3 ) by an adaptation of the of the electric motor ( 2 ) has deposited requesting torque. Hybrid drive ( 1 ) according to claim 14, characterized in that the control unit ( 9 ) with an engine control unit ( 11 ) via a serial data bus ( 10 ), wherein the engine control unit ( 11 ) a functionality for calculating a current torque of the internal combustion engine ( 3 ) whose value has been passed to the controller ( 9 ) is made available. Hybrid drive according to claim 14 or 15, characterized in that the internal combustion engine ( 3 ) and the electric motor ( 2 ) are arranged in a parallel connection. Hybrid drive according to claim 16, characterized in that the internal combustion engine ( 3 ) and the electric motor ( 2 ) have different waves separated from each other, wherein the electric motor is arranged on a drive shaft or on a wheel of the vehicle. Hybrid drive according to one of the preceding claims, characterized characterized in that at least one clutch is arranged, via the actuation of a parallel operation in another operation of internal combustion engine and electric motor can be changed. Hybrid drive according to one of the preceding claims, characterized in that in the control unit ( 9 ) a method according to any one of claims 1 to 13 is deposited.