DE102008009430A1 - Method and apparatus for operating a hybrid propulsion system - Google Patents

Abstract

The invention relates to a method for operating a hybrid drive system with an internal combustion engine (2) and an electric drive (3) with the following steps:
- Providing a desired torque (M _Soll ) indicating a to be supplied by the engine drive torque;
Determining an adapted setpoint torque (M _setpoint ) dependent on the setpoint torque (M _setpoint ) and a provided adaptation value (M _A );
- determined driving the internal combustion engine (2) depending on the adapted target torque (M _Soll ') engine sizes to adjust to that of the target torque (M _Soll) predetermined drive torque to the internal combustion engine (2);
characterized,
in that the adaptation value (M _A ) is provided as a function of a load point of the hybrid drive system, the load point indicating a moment balance existing between the internal combustion engine (2) and the electric drive (3).

Description

Technical area

The The invention relates to a method and a motor control unit for Operating a hybrid drive system. The invention particularly relates a method and a motor control unit to an adapted target torque in a hybrid propulsion system.

State of the art

at Hybrid drives with an internal combustion engine and one on the drive train arranged electric motor, a motor control is made so that the applied to the drive train moments to a desired by the driver Add torque.

To the Setting a desired Torque becomes a torque model in an internal combustion engine used, the target torque engine sizes, such. Injection quantity, ignition angle, Assigns throttle position and the like. The torque model is achieved by parametrization of an individual internal combustion engine or a motor type on a test bench. The precision of such a torque model, resulting from the difference between the desired Torque (setpoint torque) and the actually obtained actual torque determined, however, is limited and, for example, due from installation in manufacturing tolerances between 0 and 10%. The percentage Torque deviation depends additionally from the respective loading point of the engine (speed, torque, Temperature, etc.). The friction and converter losses are based on calculated by other models, which also has a certain inaccuracy subject.

Also for determining the actual torque of the hybrid drive used Electric motor, a torque model is used, which is a corresponding Inaccuracy of the provided Istmoments may have and also dependent on the load point is.

Especially When idling the drive system, it is important to the torque contributions of the internal combustion engine and the electric motor to know exactly because torque deviations between the Target moment and the over the corresponding torque models determined torque immediately as speed changes make noticeable, the first balanced by intervention of an idle speed controller Need to become.

As well it is also higher Speeds are important, that the entire set and actual moment exactly match, so that the driver set a desired speed by means of the accelerator pedal and can hold this. Otherwise changes due to torque inaccuracies the engine speed, without the driver the accelerator pedal angle, with to which this specifies the desired torque (driver request torque) changes. These Effects are perceived by the driver as uncomfortable.

at a conventional one Drive system with only one internal combustion engine are functions in an engine control unit provided that adapt idle torque loss and idle thereby increase the torque accuracy. This is usually done by applying the predetermined setpoint torque with a previously determined adaptation value. The determination of this adaptation value is based on the knowledge that in standing (unloaded) idling at constant speed, the output at the output shaft torque exactly 0 Nm. This is the load point of the internal combustion engine clearly determined.

at however, such an algorithm is no longer a hybrid drive suitable because the engine in idle mode any load point can assume, depending on which load torque of the electric motor, which may be in generator mode, for example, on the Output shaft exerts. Thus, the required for constant idling 0 Nm at the output shaft through a corresponding combination of positive torque (drive torque) of the internal combustion engine and negative torque (load torque) of the Reach electric motor.

With the conventional one Adaptive functions, it is thus not possible in the hybrid drive, the Torque inaccuracies reliable to determine and balance.

It Object of the invention, the torque accuracy of the entire To improve drivetrain and thereby achieve in particular that even with changes in the load points, the idle speed of a Hybran drive remains constant. This can continue to be achieved that the driver a desired Speed can be better adjusted with the accelerator pedal.

Disclosure of the invention

These The object is achieved by the method for operating a hybrid drive system according to claim 1 and by the engine control and the engine system according to the siblings claims solved. Further advantageous embodiments of the invention are specified in the dependent claims.

• – Bereitstellen eines Soll-Drehmoments, das ein vom Verbrennungsmotor zu lieferndes Antriebsmoment angibt;
• – Ermitteln eines adaptierten Soll-Drehmoments abhängig von dem bereitgestellten Soll-Drehmoment und einem bereitgestellten Adaptionswert;
• – Ansteuern des Verbrennungsmotors mit in Abhängigkeit von dem adaptierten Soll-Drehmoment ermittelten Motorgrößen, um ein von dem Soll-Drehmoment abhängiges Antriebsmoment einzustellen,

wobei der Adaptionswert abhängig von einem Lastpunkt des Hybridantriebsystems bereitgestellt wird, wobei der Lastpunkt eine Angabe über eine zwischen Verbrennungsmotor und Elektroantrieb bestehende Momentenbilanz angibt.According to a first aspect, a method for operating a hybrid drive system with an internal combustion engine and an electric drive is provided. The method comprises:

• Providing a desired torque indicative of a drive torque to be supplied by the internal combustion engine;
• - Determining an adapted target torque depending on the provided target torque and a provided adaptation value;
• Activating the internal combustion engine with engine variables determined as a function of the adapted setpoint torque in order to set a drive torque dependent on the setpoint torque,

wherein the adaptation value is provided as a function of a load point of the hybrid drive system, wherein the load point indicates an indication of an existing between engine and electric drive torque balance.

The above method allows it, in a hybrid drive, the torque adaptation of the target torque dependent from the load point at which the hybrid drive system from internal combustion engine and electric drive is operated. Thereby can Disadvantages are avoided, resulting from a torque adjustment with a constant adaptation value, since, depending on the load point of the Influence of the load torque of the electric drive independent of the respective load point, the target torque is applied. The above method therefore provides, adapted for different load points Provide adaptation values.

According to one embodiment become several adaptation values and their associated load points provided in an adaptation value map.

In In this case, the integrator portion of the speed control is added uses the adaptation value for to update the load point. The load point results from the provided by the engine actual torque and that recorded by the electric motor Actual moment and is provided by the engine control unit.

Farther the provided adaptation value can be added to the setpoint torque to obtain the adapted setpoint torque.

According to one preferred embodiment the information about The load point can be determined by that of the electric drive recorded load torque during an unloaded idling of the hybrid drive system is determined.

Farther can the from the indication over the load point provided during an unloaded idle of the hybrid drive system.

Especially can while the unloaded idling of the hybrid drive system, a speed control be active, wherein the adaptation value assigned to the instantaneous load point with the help of a size from the Speed control is updated. It can be the current Load point associated with an integrator value from the speed control provided with an integration component to be updated. Alternatively, the current load point assigned adaptation value with the help of a total sum moment of the Internal combustion engine and the electric drive minus the torque loss can be determined.

Furthermore, the updating can take place by replacing the adaptation value assigned to the instantaneous load point by the integrator value, if the control loop of the speed control has not taken into account the instantaneous adaptation value assigned to the load point, or
The updating can be done by applying the value of the adaptation value associated with the instantaneous load point to the integrator value if the control loop of the speed control has taken into account the instantaneous adaptation value assigned to the load point.

• – eine Drehmomentenmodelleinheit zum Ansteuern des Verbrennungsmotors mit abhängig von einem adaptierten Soll-Drehmoment ermittelten Motorgrößen,
• – eine Einheit zum Ermitteln des adaptierten Soll-Drehmoments abhängig von dem Soll-Drehmoment und einem bereitgestellten Adaptionswert, um ein von dem Soll-Drehmoment abhängiges Antriebsmoment einzustellen;
• – eine Adaptionswerteinheit zum Bereitstellen des Adaptionswertes abhängig von einer Angabe über einen Lastpunkt des Hybridantriebsystems, wobei der Lastpunkt eine Angabe über eine zwischen Verbrennungsmotor und Elektroantrieb bestehende Momentenbilanz angibt.

In another aspect, an engine control unit is provided for operating a hybrid propulsion system having an internal combustion engine and an electric drive. The engine control unit includes:

• A torque model unit for activating the internal combustion engine with engine variables determined as a function of an adapted setpoint torque,
• A unit for determining the adapted setpoint torque as a function of the setpoint torque and a provided adaptation value in order to set a drive torque dependent on the setpoint torque;
• An adaptation value unit for providing the adaptation value as a function of an indication of a load point of the hybrid drive system, the load point indicating an indication of a torque balance existing between the internal combustion engine and the electric drive.

According to a further embodiment, a motor control unit is provided with a speed control for adjusting a rotational speed of the hybrid drive system in an unloaded idle and for providing a variable from the speed control, with the help of which provided by the indication of the load point adaptation value during ei nes unloaded idling of the hybrid drive system is updated.

According to one another aspect is an engine system with a hybrid drive system, having an internal combustion engine and an electric drive, and provided with the above engine control unit.

According to one Another aspect is a computer program is provided, the program code contains when, on a data processing unit, in particular in a motor control unit executed is performing the above method.

Brief description of the drawings

preferred embodiments The invention will be described below with reference to the accompanying drawings explained in more detail. It demonstrate:

1 a hybrid drive system according to an embodiment of the invention; and

2 a schematic representation of the function of a motor controller according to an embodiment of the invention.

Description of embodiments

In 1 is a hybrid drive system with a first drive unit, in particular an internal combustion engine 2 , and a second drive unit, in particular an electric motor 3 connected to a common output shaft 4 are arranged, shown. The internal combustion engine 2 is about a clutch 5 with the electric motor 3 coupled. The components of the drive system 2 . 3 . 4 . 5 be through a motor control unit 6 controlled.

For controlling the internal combustion engine 2 As a rule, an indication of a desired torque is provided, from which with the aid of a torque model engine variables, such. B. throttle position, ignition angle, injection quantity and the like are determined, with which the internal combustion engine 2 is controlled. The torque model is for the internal combustion engine 2 parameterized individually or type-dependent, so that ideally sets when specifying the specification of the target torque, an actual torque that corresponds to the target torque exactly.

However, the parameterization is carried out in practice only with a limited accuracy, so that there is a deviation between the predetermined target torque and that of the internal combustion engine 2 provided actual torque can come. These deviations can also over the life of the internal combustion engine 2 vary.

Around To compensate for these deviations, is in a conventional Drive system with only one internal combustion engine in unloaded idling mode, in which no torque is applied to the output shaft, an adaptation value determined, the predetermined target torque, for example, one over a Accelerator pedal of a motor vehicle corresponds to predetermined driver's desired torque, is added. This makes possible, that the internal combustion engine according to a adjusted nominal torque is operated. The determined adaptation value is thus adapted to the idling operation of the internal combustion engine.

In hybrid drive systems, idling can now occur at different load points, depending on the torque of the electric motor 3 of the hybrid drive absorbs. Although the adaptation in idle mode without concern of an external load torque on the output shaft 4 can be performed, there are many load points on which the hybrid drive system can be located. For example, the internal combustion engine 2 give off a positive torque (drive torque) by the electric motor 3 , which is, for example, in a generator mode is recorded. As a result, the total torque on the output shaft is 0 Nm.

The for the needed different load points Adaptation values to compensate for the inaccuracies of the moment model can to be different. It is therefore proposed that the adaptation value, with the specified target torque before is converted to engine sizes, in a hybrid drive system depending on the particular load point of the hybrid drive system in unloaded idle mode.

In 2 FIG. 3 is a schematic block diagram illustrating the method of operating a hybrid propulsion system. FIG 1 and a method for teaching adaptation values depending on load points of a hybrid propulsion system 1 shown. The methods may be part of the engine control and are preferably in the common engine control unit 6 executed, which also includes other functions for controlling the internal combustion engine 2 the hybrid drive system or the electric motor provided therein 3 contains. The schematic representation of 2 shows the part of the control of the hybrid drive system, the control of the internal combustion engine 2 concerns.

It is assumed that a predetermined desired torque M _Soll , for example, in an operating state of the hybrid drive system in which the entire torque only via the internal combustion engine 2 should be provided, which is specified by the driver via an accelerator pedal position Driver request torque corresponds. This predetermined setpoint torque M _Soll becomes a selection element 11 z. B. supplied in the form of a demultiplexer. The desired torque M _Soll is supplied from the selector element 11 depending on a selection signal L to a summer 12 passed. The selection signal L indicates whether a likewise provided speed control 17 is active or not. The speed control 17 is usually disabled when the internal combustion engine 2 not in an unloaded idle mode. The indication of whether the engine is in an unloaded idling mode is specified externally or in the Mo gate control unit 6 determined from other farm sizes. As soon as the predetermined desired torque M _Soll changes or increases, the speed control is deactivated, for. B. by the selection signal is changed and thereby the target torque M _Soll to the summing 12 is forwarded.

In the summator 12 is applied to the target torque M _Soll with an adaptation value M _A , which indicates a correction torque. Preferably, the adaptation value is added to the predetermined setpoint torque M _Soll . However, there are also other options conceivable to apply the setpoint torque M _target with a correction value, for. B. by multiplication and the like. The corrected target torque M _Soll becomes a torque model unit 13 supplied, which determined from the predetermined corrected target torque M _target engine sizes S1, S2, S3, etc., and this the internal combustion engine 2 makes available to operate this. The engine sizes provided may be, for example, the ignition timing (ignition angle), the throttle position and the injection quantity. Other adjustable motor sizes for controlling the internal combustion engine 2 , with which the corrected target torque can be adjusted, are conceivable.

The adaptation value M _A is from an adaptation value unit 14 provided. The adaptation value unit 14 includes in the embodiment shown an adaptation value memory 15 and an interpolation unit 16 , Furthermore, the adaptation value unit receives 14 an indication of the instantaneous load point (torque specification) of the hybrid drive in the form of a load point signal LPS. The load point signal gives the torque contributions of the internal combustion engine 2 and the electric motor 3 in the unloaded idle mode of the hybrid drive system. This is usually done by the internal combustion engine 2 a positive drive torque provided by a negative load torque of the electric motor 3 , which is in a generator mode, for example, for charging a vehicle battery is recorded. As a result, the drive torque on the output shaft is 0 Nm.

In the adaptation value unit 14 is determined from the provided information about the load point of the adaptation value M _A. This can be done, for example, by means of an adaptation value map stored in the adaptation value memory 15 is stored. Using the interpolation unit 16 For example, adaptation values for load points are determined by an interpolation for which there are no concrete values in the adaptation value memory 15 are deposited. Alternatively, adaptation values can be determined using a suitable adaptable function with respect to the given load point.

When using an adaptation map, it is necessary that the adaptation values that are to be stored in the map, the inaccuracies of the torque model with respect to the individual internal combustion engine or those that are due to the aging of the internal combustion engine 2 give, compensate. The adaptation values M _A should therefore be before commissioning of the internal combustion engine 2 be taught in and updated continuously or at regular intervals.

The updating of an adaptation value stored in the adaptation map takes place in the unloaded idling mode of the hybrid drive system 1 , In unloaded idle mode, the speed control 17 activated to set a constant speed control torque M _{rule of} the selection unit 11 provides. The selection signal L indicates that the control torque M _Rule instead of the setpoint torque M _Soll the summing 12 provided. The speed control 17 receives as inputs a predetermined target idle speed n _{Soll_Leerlauf} and the instantaneous actual speed n _actual . The speed control 17 is preferably designed as a PID controller and has a proportional element P, an integrator I and a differentiator D. The integration element I adjusts in the steady state of the speed control to a specific integrator value.

The integrator value represents a correction value M _K for the adaptation value M _A at the corresponding instantaneous load point, since the speed control 17 in the control loop also the summing element 12 contains, by the control torque M _rule also during the active speed control with the current adaptation value M _A from the adaptation value unit 14 is charged. The correction value M _K is therefore added to the existing at the load point adaptation value M _A. Alternatively, the correction value M _{K can} also be calculated from the total sum torque of the internal combustion engine 2 and the electric motor 3 minus the loss moments are determined.

The adaptation of the adaptation values stored in the adaptation value map can always be done occur when the hybrid drive system is in unloaded idle and the speed control is in the steady state. Then, the integration value M _K has assumed a constant amount.

In the adaptation value map stored in the memory 15 is stored, becomes each load point of the internal combustion engine 2 an adaptation value M _A stored. Furthermore, the adaptation value map can take into account different engine and converter oil temperatures and different speeds. When determining the load point, it is sufficient to determine the load point of the internal combustion engine 2 to determine, because the electric motor 3 in unloaded idle must provide exactly the same amount of torque with a negative sign.

In order to avoid large jumps when learning the adaptation values, one can use the integrator value of the adaptation value unit 14 limit provided correction values M _K for each adaptation step and / or weighted with a weighting factor.

alternative you can also the adaptation value in the feedforward control of the idle control to flow in, instead of correcting the modeled loss moments.

Claims (13)

Method for operating a hybrid drive system with an internal combustion engine and an electric drive, comprising the following steps: - providing a setpoint torque (M _setpoint ) that is provided by the internal combustion engine ( 2 ) indicates the drive torque to be supplied; - Determining an adapted setpoint torque (M _Soll ') depending on the desired torque and a provided adaptation value (M _A ); - Controlling of the internal combustion engine with depending on the adapted setpoint torque (M _Soll ') determined engine sizes to the of the target torque (M _Soll ) predetermined drive torque to the internal combustion engine ( 2 ); characterized in that the adaptation value (M _A ) is provided as a function of a load point of the hybrid drive system, the load point being an indication of a difference between an internal combustion engine ( 2 ) and electric drive ( 3 ) indicates existing torque balance. The method of claim 1, wherein a plurality of adaptation values (M _A ) and the load points associated therewith are provided in an adaptation value map. The method of claim 1 or 2, wherein the provided adaptation value (M _A ) to the target torque (M _Soll ) is added to obtain the adapted target torque (M _Soll '). Method according to one of claims 1 to 3, wherein the indication of the load point is determined by that of the electric drive ( 3 ) recorded load torque during unloaded idling of the hybrid drive system is determined. Method according to one of claims 1 to 4, wherein the provided by the indication of the load point adaptation value (M _A ) during an unloaded idling of the hybrid drive system is updated. The method of claim 5, wherein during the unloaded idling of the hybrid drive system, a speed control ( 17 ) is active, wherein the adaptation value (M _A ) assigned to the instantaneous load point is updated by means of a variable from the speed control. Method according to Claim 6, in which the adaptation value (M _A ) assigned to the instantaneous load point is determined by means of an integrator value from the speed control provided with an integration component ( 17 ) is updated. Method according to Claim 6, in which the adaptation value (M _A ) assigned to the instantaneous load point is determined by means of a total sum torque of the internal combustion engine ( 2 ) and the electric drive ( 3 ) minus the loss moments. Method according to claim 7, wherein the updating takes place by replacing the adaptation value associated with the instantaneous load point by the integrator value, if a control loop of the speed control ( 17 ) has not taken into account the instantaneous adaptation value (M _A ) assigned to the load point, or wherein the updating takes place by applying the adaptation value (M _A ) associated with the instantaneous load point to the integrator value, if the control loop of the speed control ( 17 ) has taken into account the instantaneous adaptation value (M _A ) assigned to the load point. Engine control unit ( 6 ) for operating a hybrid propulsion system having an internal combustion engine ( 2 ) and an electric drive ( 3 ), comprising: - a torque model unit for driving the internal combustion engine ( 3 ) with determined depending on an adapted setpoint torque (M _Soll ') Mo torgrößen to set one of the desired torque (M _Soll ) predetermined drive torque; - one unity ( 12 ) for determining the adapted setpoint torque (M _setpoint ) as a function of the setpoint torque (M _setpoint ) and a provided adaptation value (M _A ); characterized by: - an adaptation value unit ( 14 ) for providing the adaptation value (M _A ) depending on a load point of the hybrid drive system, wherein the load point is an indication of an between internal combustion engine ( 2 ) and electric drive ( 3 ) indicates existing torque balance. Engine control unit ( 6 ), further comprising: a speed control for adjusting a speed of the hybrid drive system in an unloaded idle and for providing a variable from the speed control ( 17 ), with the help of which the adaptation value (M _A ) provided by the indication of the load point is updated during an unloaded idling of the hybrid drive system. Engine system with a hybrid propulsion system that has an internal combustion engine ( 2 ) and an electric drive ( 3 ), and with the engine control unit ( 6 ) according to any one of claims 10 to 11. Computer program containing a program code which, when running on a computing device, a method according to a the claims 1 to 9 executes.