DE102013223267A1 - Method and device for adapting a torque loss of an internal combustion engine in a hybrid drive system - Google Patents

Abstract

The invention relates to a method for adapting a torque loss of an internal combustion engine (2) in a hybrid drive system, wherein the adaptation of the loss torque is performed using an adaptation value, comprising the following steps: - Setting an operating point of the internal combustion engine (2) with a predetermined engine torque (M ) and a predetermined target speed (nset); - Controlling the target speed (nSoll) of the internal combustion engine (2) with a speed control (11); - Determining a permanent control deviation of the speed control (11); and - determining the adaptation value of the adaptation variable as a function of the permanent control deviation of the speed control (11).

Description

Technical area

The invention relates to hybrid drive systems with an internal combustion engine, in particular a method for determining and / or adapting a loss torque of the internal combustion engine.

State of the art

The loss torques of an internal combustion engine, which are primarily caused by friction, are subject to great fluctuations even in internal combustion engines of the same series and also change due to wear over the life of the engine.

In hybrid drive systems, in which in addition to the internal combustion engine and an electric drive motor is usually provided to adjust the load distribution and to adjust the total power output precise knowledge of a currently issued from the engine engine torque is necessary. In order to determine the engine torque delivered effectively by the internal combustion engine, the knowledge of a loss torque of an internal combustion engine is necessary.

In order to provide as accurate as possible information about the current torque loss of the internal combustion engine, adaptation methods are necessary during operation of the internal combustion engine, which make plausible a corresponding statement of the torque loss and correct if necessary.

In non-hybrid drive systems in which only an internal combustion engine is provided, in conventional concepts, the adaptation during idling of the internal combustion engine can be provided with active idle speed control. In particular, an integrator component of the idle speed control can be used there for the adaptation.

Disclosure of the invention

According to the invention, a method for adapting a torque loss of an internal combustion engine in a hybrid drive system according to claim 1 and a device, an engine system and a computer program according to the independent claims are provided.

Further embodiments are specified in the dependent claims.

• – Einstellen eines Betriebspunkts des Verbrennungsmotors mit einem vorgegebenen Motormoment und einer vorgegebenen Solldrehzahl;
• – Regeln der Solldrehzahl des Verbrennungsmotors mit einer Drehzahlregelung;
• – Bestimmen einer permanenten Regelabweichung der Drehzahlregelung; und
• – Bestimmen des Adaptionswerts der Adaptionsgröße abhängig von der permanenten Regelabweichung der Drehzahlregelung.

According to a first aspect, a method for adapting a torque loss of an internal combustion engine in a hybrid drive system is provided, wherein the adaptation of the torque loss is performed by means of an adaptation variable. The method comprises the following steps:

• - Setting an operating point of the internal combustion engine with a predetermined engine torque and a predetermined target speed;
• - Controlling the target speed of the internal combustion engine with a speed control;
• Determining a permanent control deviation of the speed control; and
• - Determining the adaptation value of the adaptation variable depending on the permanent control deviation of the speed control.

Furthermore, the predetermined engine torque can be adjusted by driving an electric drive machine coupled to the internal combustion engine.

In particular, the internal combustion engine can be coupled to the electric drive machine and decoupled from further torque-receiving components in order to adapt the torque loss, so that the engine torque output by the internal combustion engine is completely absorbed by the electric drive machine.

While in motor systems with only one internal combustion engine, an operating range defined for the adaptation of the lost torque regularly occurs during normal operation of the engine system in a motor vehicle, the operating case of the idling of the internal combustion engine in a hybrid drive system is generally not provided. The operating conditions provided there usually include an electric operation, d. H. the purely electric operation when the internal combustion engine is switched off and decoupled, the hybrid drive operation, in each of which a partial torque is provided both by the internal combustion engine and by the electric drive machine, as well as the charging operation, in which the electric drive machine is driven as a generator and the mechanical energy required for this can be provided to the internal combustion engine. An operating state in which the engine torque provided by the engine just corresponds to the torque loss of the internal combustion engine, as is the case for example in idle mode, therefore no longer occurs. The previously made in idle mode adaptation of the loss torque can therefore not be carried out in the usual manner.

The above method for adapting the loss torque of the internal combustion engine provides, for. B. with open driveline, ie only with a coupling between the engine and the electric drive machine to set several operating points by constant Output power are defined. The output power is proportional to the product of the engine torque provided by the engine and the speed of the engine. If the hybrid drive system is in the charging mode in which the internal combustion engine operates the electric drive motor with the drive train open, different operating points can be assumed by varying the engine torque and the engine speed provided by the internal combustion engine for each identical engine output.

If the loss torque is properly adapted and corresponds to the actual torque loss, then a variation of the engine torque provided and a corresponding variation of a setpoint speed for a speed control provided in the charging mode result in the same engine power output by the engine, i. H. with constant product of engine torque and speed, no or no significant deviation of the speed control.

However, if a control deviation is detected in the speed control, z. B. via a permanently nonzero integrator component, so that a permanent control deviation can be detected, indicating that the engine torque provided does not correspond to a predetermined engine torque. In this case, an adaptation of the engine torque loss used for adjusting the engine torque can be made in order to minimize or eliminate the control deviation occurring in this case.

A goal of the adjustment of the operating point is to adjust for the adaptation of the loss torque different operating points with a constant product of engine torque and speed. Based on a permanent control deviation of a speed control required to set the speed, the adaptation can be carried out. By choosing different operating points, it is also possible to adapt the loss torque for the internal combustion engine, without a noticeable change in the system behavior takes place. In the charging mode, the electric drive machine, which is operated as a generator, provides the same mechanical power, so that a higher-level hybrid drive control, which specifies the operating mode to be selected, does not have to take account of the implementation of this adaptation method.

Furthermore, a high adaptation quality can be ensured by the targeted approach of operating points, which are defined by the engine torque and the speed, in particular if the adaptation is carried out depending on the operating range, z. For example, in operating areas where sufficient data is not yet available.

According to one embodiment, the speed control can have an integrator component and the permanent control deviation can be determined by an integrator value of the integrator component.

Furthermore, adaptation values can be determined at a plurality of operating points, with the plurality of operating points being selected as operating points in which identical output powers of the internal combustion engine are present.

It can be provided that the adaptation values are assigned to the relevant operating points or operating ranges from a plurality of operating points.

• – seit einer vorbestimmten Zeitdauer keine Adaption des Verlustmoments ausgeführt worden ist; und/oder
• – die benachbarten Betriebsbereichen zugeordneten Adaptionswerte einen Unterschied aufweisen, der einen Unterschiedsschwellenwert übersteigt; und/oder
• – eine Adaptionshäufigkeit eine geringere Häufigkeit angibt als ein vorgegebener Häufigkeitsschwellenwert.

The operating points may be selected to be in different operating ranges, with an operating range being selected as the next operating range to be selected for an adaptation of the torque loss, if

• - No adaptation of the loss torque has been carried out for a predetermined period of time; and or
• The adaptation values associated with adjacent operating areas have a difference that exceeds a difference threshold value; and or
• An adaptation frequency indicates a lower frequency than a predefined frequency threshold value.

Furthermore, an adaptation value of the adaptation variable can be stored in an adaptation map for each operating region, an adaptation value determined for one of the operating regions applying the adaptation value stored in the relevant operating region and storing an updated adaptation value in the relevant operating region.

• – einen Betriebspunkt des Verbrennungsmotors mit einem vorgegebenen Motormoment und einer vorgegebenen Solldrehzahl einzustellen;
• – die Solldrehzahl des Verbrennungsmotors mit einer Drehzahlregelung zu regeln;
• – eine permanente Regelabweichung der Drehzahlregelung zu bestimmen; und
• – den Adaptionswert der Adaptionsgröße abhängig von der permanenten Regelabweichung der Drehzahlregelung zu bestimmen.

According to a further aspect, a hybrid drive control is provided for adapting a torque loss of an internal combustion engine, wherein the loss torque is adapted by means of an adaptation variable, wherein the hybrid drive control is designed to

• - Set an operating point of the internal combustion engine with a predetermined engine torque and a predetermined target speed;
• - To control the target speed of the internal combustion engine with a speed control;
• - to determine a permanent control deviation of the speed control; and
• - To determine the adaptation value of the adaptation variable as a function of the permanent control deviation of the speed control.

• – einen Verbrennungsmotor;
• – eine elektrische Antriebsmaschine; und
• – die obige Hybridantriebssteuerung.

In another aspect, a hybrid propulsion system is provided, comprising:

• An internal combustion engine;
• An electric drive machine; and
• The above hybrid drive control.

In particular, the internal combustion engine may be coupled to the electric drive machine such that the engine torque provided is received by the electric drive machine, wherein the hybrid drive control is configured to operate the hybrid drive system such that the adaptation of the lost torque is performed when the engine torque provided by the electric drive machine is completely absorbed.

Brief description of the drawings

Embodiments are explained below with reference to the accompanying drawings. Show it:

1 a schematic representation of a hybrid drive system with an internal combustion engine and an electric drive machine;

2 a flowchart for illustrating a method for adapting a torque loss of an internal combustion engine in a hybrid drive system; and

3 a diagram illustrating the selection of operating points from different operating ranges for the adaptation of the internal combustion engine.

Description of embodiments

1 shows a schematic block diagram of a hybrid drive system 1 , in particular for the drive of a motor vehicle. The hybrid drive system 1 includes an internal combustion engine 2 that has a power train 5 with a first clutch 3 is coupled. The first clutch 3 is designed to take the output train 5 of the internal combustion engine 2 with an electric drive machine 4 to couple or decouple from this.

The output train 5 is through the electric drive machine 4 consistently formed. On the output side of the electric drive machine 4 is the output train 5 with a second clutch 6 coupled with the output train 5 with a powertrain 7 can be coupled and z. B. via a (not shown) gear with (not shown) drive wheels can be connected.

The hybrid drive system 1 further comprises a hybrid drive control 10 showing the load distribution in the hybrid propulsion system 1 as well as its operating modes. Thus, for example, in an electric operating mode, a drive torque that via the output train 5 is passed to the drive wheels are provided, wherein the electric drive machine 4 using the first clutch 3 from the internal combustion engine 2 decoupled and by closing or keeping closed the second clutch 6 to the drive train 7 is coupled. The electric drive machine 4 is doing about an electrical energy storage 8th supplied with electrical energy. Furthermore, the electric drive machine 4 through the hybrid drive control 10 controlled to provide a desired drive torque.

In one of the hybrid drive control 10 set hybrid mode, the drive torque from the engine 2 and from the electric drive machine 4 with closed first and second clutch 3 . 6 provided jointly, the internal combustion engine 2 and the electric drive machine 4 in each case a partial drive torque on the output train 5 provide.

In a charging mode, the hybrid drive system is 1 over the opened second clutch 6 from the drive train 7 and thus decoupled from the drive wheels. To the electrical energy storage 8th However, it is intended to charge the internal combustion engine 2 to operate and with the thus provided engine torque M with the first clutch closed 3 the electric drive machine 4 to drive as a generator. By the regenerative operation electrical energy is generated, which is the electrical energy storage 8th is supplied. Here is the converted power, ie that of the internal combustion engine 2 over the power train 5 to the electric drive machine 4 supplied power, given. The power is provided by the hybrid drive control 10 given and can be after the filling state of the electrical energy storage 8th and the efficiency of converting the mechanical power into electrical energy by the electric drive machine 4 judge.

The hybrid drive control 10 can the internal combustion engine 2 by setting an engine torque M and at the same time drive the electric drive 4 to receive the supplied motor torque M for generating electrical energy.

Furthermore, the hybrid drive control includes 10 a working speed control 11 that the internal combustion engine 2 continues to drive so that a certain of the hybrid drive control 10 specified setpoint speed n _{setpoint is} set. In this way, the internal combustion engine 2 through the hybrid drive control 10 are operated to provide a predetermined engine torque M at a predetermined target speed n _Soll . At the same time, the electric drive machine 4 operated as a generator so that the provided mechanical power is converted into electrical energy, the electrical energy storage 8th is supplied.

That of the internal combustion engine 2 over the first clutch 3 to the electric drive machine 4 provided engine torque M is essentially dependent on the internal torque of the internal combustion engine 2 , which corresponds to the torque generated by the combustion of fuel, and a loss torque caused by friction and charge exchange losses in the internal combustion engine 2 is effected. The difference results in the engine torque M provided, via the first clutch 3 on the input side to the electric drive machine 4 provided.

The loss torque of the internal combustion engine 2 is for a type of internal combustion engine usually only vaguely known and can also over the life of the engine 2 due to the wear of components as well as the temperature of the internal combustion engine 2 to change. It is therefore intended to adjust the loss moment using an adaptation method regularly, so that the electric drive machine 4 provided engine torque M can be set or specified more accurately.

For the adaptation of the loss moment will be described below with reference to the flowchart in the 2 proposed method proposed.

In step S1, it is first checked whether a mode suitable for adaptation of the hybrid drive system 1 is present. As a suitable mode of operation, the Aufladebetriebsart is considered, in which the hybrid drive system 1 through an opened second clutch 6 from the powertrain 7 and the drive wheels is decoupled. Furthermore, in the charging mode, the internal combustion engine 2 usually in operation and delivers stationary with the first clutch closed 3 the predetermined engine power at a given, by the engine torque M and the corresponding speed n predetermined operating point to the electric drive machine 4 , The electric drive machine 4 then takes the provided engine power completely and converts them into electrical energy, z. B. for charging the electrical energy storage 8th , In step S1, the corresponding mode with closed first clutch 3 and opened second clutch 6 or z. B. a Aufladebetriebsart found (alternative: Yes), the method proceeds to step S2. Otherwise (alternative: No), jump back to step S1.

In 3 For example, in a diagram those operating points B1-B4 defined by the engine torque M and the rotational speed n are shown which lead to the same output power at the electric drive machine 4 to lead. These operating points B1-B4 are located on the hyperbola H shown for a specific output power. That is to say, the operating points B1-B4 indicated by each of the hyperbolas H correspond to operating points of the same engine power as those of the internal combustion engine 2 to the electric drive machine 4 provided.

To provide the engine power, it is necessary to know the engine torque M exactly that to the electric drive machine 4 provided. However, the engine torque M can be adjusted only with a precise knowledge of the loss torque, since the internal moment is the driving of the engine 2 through the hybrid drive control 10 results and the engine torque M is formed as the difference between the internal torque and the torque loss.

Furthermore, the hybrid drive control determines 10 via a corresponding control of the electric drive machine 4 or their power electronics that of the electric drive machine 4 to be absorbed load torque. The load torque to be absorbed is determined there by the generator-generated phase currents, which can be set by the power electronics.

In step S2 is now determined for the existing or set operating point, whether the taking place by the predetermined engine power control of the engine 2 for the delivery of a specific engine torque M at a corresponding speed n is such that the speed control 11 no permanent control deviation is detected or an amount of the control deviation is less than a predetermined control deviation threshold value. A permanent control deviation can be achieved, for example, by evaluating an integrator component of the speed control 11 be determined. If an integrator component not equal to zero or an integrator value that is greater in magnitude than a predetermined integrator threshold value is detected, then it is necessary to adapt the loss torque.

The loss torque is adapted when a control deviation occurs as the difference between the current speed n and the target speed n _Soll . If the deviation is positive, then the current speed is too high and thus the engine torque M greater than that of the electric drive machine 4 recorded load torque. It follows that the assumption of the loss torque is too high and this must be reduced accordingly by the adaptation value. Conversely, if the deviation is negative, the current speed is too low and thus the engine torque M less than that of the electric drive machine 4 recorded load torque. It follows that the assumption of the loss torque is too low and this must be increased accordingly by the adaptation value.

The adaptation can be made depending on the operating area. For this purpose, it is provided to use an adaptation map, which summarizes operating points to operating ranges, in which the loss torque is adapted by a respective adaptation size. This is in 3 represented by the division into the operating areas (shown as fields A). That is, operating points within one of the operating areas A are acted upon by an associated adaptation variable in order to be able to undertake a corresponding correction of the loss torque in these operating areas. For each of the operating areas A, the in 3 are shown, thus an individual adaptation size is determined.

If an adaptation was carried out at the operating point in accordance with step S2, then the determined adaptation variable corresponding to the operating region A is stored in the adaptation characteristic field.

In step S3 is now checked whether the adaptation process should continue to continue. This can be done on the basis of a termination criterion. For example, in the hybrid drive control 10 a mode change may be provided, as a result, the speed control 11 is deactivated. In this case, the adaptation procedure should be terminated. Also other termination criteria can be considered. If it is determined in step S3 that the adaptation is to be aborted (alternative: yes), the method returns to step S1. Otherwise (alternative: no), the method is continued with step S4.

In step S4, a further operating point B1-B4 is selected for a further operating range A, which is characterized in that the same engine power is provided there. It is an operating point B1-B4, which lies on the same hyperbola H as the previously measured operating point B1-B4. Preferably, the new operating point B1-B4 is selected such that it is located in a different operating range A, in order to determine correspondingly the adaptation value associated with this operating range A.

In particular, one operating region A can be selected as the relevant operating region A, for which there are still no sufficient adaptation values for the adaptation variable or in which no adaptation value for the loss torque has been determined during a predetermined period of time. The operating range A, which is selected for the selection of the next operating point B1-B4, can furthermore take place, for example due to unusually high differences (differences greater than a predefined difference threshold value) to adaptation values of operating points from adjacent operating ranges A, in the adaptation characteristic field. Such high differences may occur, for example, due to very different adaptation frequencies (differences between adaptation frequencies greater than a predetermined frequency threshold value) in adjacent operating areas A or else due to the time interval to the last adaptation in the relevant operating area A.

After the new operating point B1-B4 has been set in a step S5, ie the internal combustion engine 2 is operated in accordance with the new operating point B1-B4, a renewed monitoring of the Integratoranteils the speed control 11 performed. The new operating point B1-B4 corresponds to an operating point at which the engine torque M and a corresponding associated setpoint speed n _{Soll are} set and the electric drive machine 4 or an associated power electronics is so controlled that they can absorb the mechanical power and regenerate into electrical energy. This is done by jumping back to step S2. If a continuous control deviation is also detected there, then the adaptation value of the selected operating range A must be changed.

The adaptation variable is designed to act multiplicatively and / or additively on a base loss moment predetermined, in particular, for the relevant operating range A, so as to be able to adapt the loss moment to be taken into account in the relevant operating range A. Initially, adaptation values assigned to the operating areas A are stored. The adaptation value of the adaptation variable in the last assumed operating range A can be changed iteratively, for example, as a function of the sign of the integrator value. Alternatively, the value of the adaptation variable can also be adapted according to the sign and the value of the integrator value as a measure of the height of the control deviation.

Claims (14)

Method for adapting a loss moment of an internal combustion engine ( 2 ) in a hybrid drive system, wherein the adaptation of the loss torque is performed by means of an adaptation variable, comprising the following steps: - setting an operating point of the internal combustion engine ( 2 ) with a predetermined engine torque (M) and a predetermined target speed (n _target ); - rules of the target rotational speed (n _Soll) of the engine ( 2 ) with a speed control ( 11 ); Determining a permanent control deviation of the speed control ( 11 ); and determining the adaptation value of the adaptation variable as a function of the permanent control deviation of the speed control ( 11 ). Method according to claim 1, wherein the predetermined engine torque (M) is controlled by driving one with the internal combustion engine ( 2 ) coupled electric drive machine ( 4 ) is set. Method according to Claim 2, in which, to adapt the loss moment, the internal combustion engine ( 2 ) with the electric drive machine ( 4 ) and decoupled from further torque-receiving components, so that the engine ( 2 ) output engine torque (M) from the electric drive machine ( 4 ) is completely absorbed. Method according to one of claims 1 to 3, wherein the speed control ( 11 ) has an integrator component and wherein the permanent control deviation is determined by an integrator value of the integrator component. Method according to one of claims 1 to 4, wherein adaptation values at a plurality of operating points (B1-B4) are determined, wherein the plurality of operating points (B1-B4) are selected as operating points, in which identical output powers of the internal combustion engine ( 2 ) are present. Method according to Claim 5, wherein the adaptation values are assigned to the relevant operating points (B1-B4) or operating ranges (A) from a plurality of operating points (B1-B4). The method of claim 6, wherein the operating points (B1-B4) are selected to be in different operating ranges (A), wherein an operating range (A) is selected as the next operating range (A) to be selected for an adaptation of the loss torque - No adaptation of the loss torque has been carried out for a predetermined period of time; and or The adaptation values associated with adjacent operating regions (A) have a difference that exceeds a difference threshold value; and or An adaptation frequency indicates a lower frequency than a predefined frequency threshold value. The method of claim 6 or 7, wherein for each operating range (A) an adaptation value of the adaptation variable is stored in an adaptation map, wherein an adaptation value determined for one of the operating areas (A) applied to the adaptation value stored in the respective operating area (A) and an updated adaptation value stores in the relevant operating area (A). Hybrid drive control ( 10 ) for adapting a loss moment of an internal combustion engine ( 2 ), wherein the loss moment is adapted by means of an adaptation variable, wherein the hybrid drive control ( 10 ) is designed to - an operating point (B1-B4) of the internal combustion engine ( 2 ) with a predetermined engine torque (M) and a predetermined target speed (nset); - the setpoint speed (nsoll) of the internal combustion engine ( 2 ) with a speed control ( 11 ) to regulate; - a permanent control deviation of the speed control ( 11 ) to determine; and - the adaptation value of the adaptation variable as a function of the permanent control deviation of the speed control ( 11 ). Hybrid drive system ( 1 ) comprising: - an internal combustion engine ( 2 ); - an electric drive machine ( 4 ); A hybrid drive control ( 10 ) according to claim 9. Hybrid drive system ( 1 ) according to claim 10, wherein the internal combustion engine ( 2 ) so with the electric drive machine ( 4 ) that the engine torque (M) provided by the electric drive machine ( 4 ), wherein the hybrid drive control ( 10 ) is adapted to the hybrid drive system ( 1 ) to operate so that the adaptation of the loss torque is performed when the provided engine torque (M) from the electric drive machine ( 4 ) is completely absorbed. Computer program adapted to carry out the method according to one of claims 1 to 8. An electronic storage medium on which a computer program according to claim 12 is stored. Hybrid drive control ( 10 ) comprising an electronic storage medium according to claim 13.

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