DE102018128239A1 - Method and control unit for operating a hybrid drive during a starting maneuver - Google Patents

Abstract

A control unit for a vehicle is described, the vehicle comprising an internal combustion engine and an electrical machine for driving a primary shaft of a starting clutch. The control unit is set up to determine whether the internal combustion engine and / or the electrical machine are used to drive the primary shaft for a starting maneuver of the vehicle. In addition, the control unit is set up as a function of setting a speed of the primary shaft for the starting maneuver.

Description

The invention relates to a hybrid vehicle. In particular, the invention relates to a method and a corresponding control unit for operating the internal combustion engine and the electric machine of a hybrid vehicle during a starting maneuver.

A vehicle with a hybrid drive, in particular with a parallel hybrid drive, comprises an internal combustion engine and an electrical machine, which can each be used individually and / or together to produce a drive torque. The internal combustion engine and the electrical machine can be coupled to one or more wheels of the vehicle via a clutch, in particular via a starting clutch. The clutch can be part of a transmission of the vehicle. In particular, the clutch can be an integrated starting element of the transmission. In particular, in a start-up situation due to speed differences between a primary shaft of the clutch (driven by the internal combustion engine and / or by the electric machine) and a secondary shaft of the clutch (which, for example, faces the transmission or is integrated in the transmission) The clutch heats up and the gear unit heats up if necessary. A high heat input in the clutch and / or in the transmission can lead to an impairment and / or a restriction of the operation of the respective component.

The present document deals with the technical task of enabling a hybrid drive of a vehicle to be operated gently, in particular as part of a starting maneuver.

The task is solved in each case by the independent claims. Advantageous embodiments include described in the dependent claims. It is pointed out that additional features of a claim dependent on an independent claim without the features of the independent claim or only in combination with a subset of the features of the independent claim can form a separate invention that is independent of the combination of all features of the independent claim can be made the subject of an independent claim, a divisional application or a late application. This applies in the same way to the technical teachings described in the description, which can form an invention that is independent of the features of the independent claims.

According to one aspect, a control unit for a vehicle (in particular for a hybrid vehicle) is described. The vehicle includes an internal combustion engine and an electric machine for driving the vehicle. The internal combustion engine and the electrical machine can be arranged in series with one another. In particular, the hybrid drive can be a parallel hybrid drive.

The internal combustion engine and the electrical machine can be set up to drive the primary shaft of a starting clutch. The starting clutch can be connected upstream of a transmission of the vehicle or integrated into a transmission of the vehicle. Furthermore, the secondary shaft of the starting clutch can be set up (possibly via a transmission or via a part of a transmission) to drive one or more drive wheels of the vehicle.

In addition, the vehicle can have a separating clutch which is arranged between the internal combustion engine and the electrical machine and is configured to decouple or couple the internal combustion engine from the electrical machine and / or from the primary shaft of the starting clutch. The primary shaft of the starting clutch can be fixed or connected to the shaft of the electrical machine via a transmission, or the primary shaft can correspond to the shaft of the electrical machine.

The control unit can be set up to determine whether the internal combustion engine and / or the electrical machine are used to drive the primary shaft for a starting maneuver of the vehicle. For this purpose e.g. Data relating to the state of charge of an electrical energy store of the vehicle are taken into account, in which electrical energy for the operation of the electrical machine is stored. As an alternative or in addition, the current driving situation can be taken into account for the starting maneuver (e.g. starting on a slope, starting with a trailer, starting with a relatively high load condition, etc.). For example, it is determined that the internal combustion engine alone, the electric machine alone or the internal combustion engine and the electric machine in combination are used for driving the primary shaft for a starting maneuver.

A starting maneuver can be regarded as a maneuver in which the vehicle is accelerated from an initial speed of 0 km / h (i.e. starting from a standstill) to a certain intermediate speed (e.g. from 5km / h or less).

In addition, the control unit is set up, depending on the selected drive form (electrical, internal combustion engine, or both electrical and internal combustion engine), the speed of the primary shaft for the Stop maneuvers. Depending on the drive form selected, at least some different speeds or different speed curves over time can be used for the starting maneuver.

By using different speeds for different types of drive during a starting maneuver, the temperature input into the starting clutch (and possibly into the transmission) can be reduced and thus the load on the starting clutch can be reduced.

The control unit may be configured to set a first speed of the primary shaft (e.g. at the start of the starting maneuver when the speed of the secondary shaft of the starting clutch is zero) if it has been determined that only the internal combustion engine is used to drive the primary shaft. The first speed can e.g. the idling and / or basic speed of the internal combustion engine (possibly multiplied by the gear ratio of an optional gear ratio between the internal combustion engine and the primary shaft), which should not be undercut for the operation of the internal combustion engine (e.g. to ensure stable and / or acoustically quiet running of the Ensure internal combustion engine).

Furthermore, the control unit can be set up to set a second rotational speed of the primary shaft (e.g. at the start of the starting maneuver) if it has been determined that the electrical machine is used to drive the primary shaft at least in part or alone. The second speed can be lower than the first speed. Lower speeds can thus be used when using the electrical machine than when using the internal combustion engine. In this way, the temperature input into the starting clutch and thus the load on the starting clutch can be reduced in an efficient manner.

The control unit can e.g. be set up to set a speed of the primary shaft of the starting clutch, which increases synchronously with the speed of the secondary shaft of the starting clutch, from the beginning of the starting maneuver if only the electric machine is used to drive the primary shaft. The temperature input into the starting clutch and thus the load on the starting clutch can be reduced to a particularly great extent.

As already explained above, the internal combustion engine and the electrical machine can be coupled or uncoupled to one another via a separating clutch. A first speed of the internal combustion engine (e.g. the idling or basic speed, possibly multiplied by a gear ratio) and a (different) secondary speed of the primary shaft of the starting clutch can then be set if it has been determined that both the internal combustion engine and the electrical one Machine to drive the primary shaft. The speed difference between the first speed and the second speed can then be intercepted by the clutch. However, the temperature input into the separating clutch is limited because only a part of the total drive torque (which acts on the starting clutch) is transmitted via the separating clutch.

The total speed difference between the first speed (which is caused by the internal combustion engine) and the speed of the secondary shaft of the starting clutch can thus be divided into a first speed difference, which acts on the separating clutch, and a second speed difference, which acts on the starting clutch , respectively. The overall load for the separating clutch and for the starting clutch can be optimized, in particular minimized, by such a division of the total speed difference.

The control unit can be set up to determine temperature data in relation to the temperature of the starting clutch and / or in relation to the temperature of the separating clutch. The temperature data can be determined using one or more temperature sensors and / or using a temperature model. Depending on the temperature data, it can then be determined whether the internal combustion engine and / or the electric machine are used to drive the primary shaft for the starting maneuver of the vehicle. Alternatively or additionally, the speed of the primary shaft for the starting maneuver can be set depending on the temperature data. By taking temperature data into account, the load on the starting clutch can be further reduced.

In particular, the control unit can be set up to determine that the electrical machine is used at least partially (or alone) to drive the primary shaft when the temperature data indicate a relatively high temperature of the starting clutch; and / or to determine that at least partially (or alone) the internal combustion engine is used to drive the primary shaft when the Temperature data indicate a relatively low temperature of the starting clutch.

Alternatively or in addition, the control unit can be set up to set a relatively low rotational speed of the primary shaft, in particular at the beginning of the starting maneuver, when the temperature data indicate a relatively high temperature of the starting clutch; and / or to set a relatively high speed of the primary shaft, in particular at the start of the starting maneuver, when the temperature data indicate a relatively low temperature of the starting clutch.

The control unit can be set up to determine a first torque that is to be generated for the starting maneuver by the internal combustion engine on the primary shaft, and to determine a second torque that is to be generated for the starting maneuver by the electrical machine on the primary shaft. The speed of the primary shaft of the starting clutch can then be set as a function of the first torque and / or as a function of the second torque. By taking the torque generated by the respective drive module into account, the load on the starting clutch can be further reduced.

According to a further aspect, a vehicle, in particular a (road) motor vehicle (such as a passenger car or a truck or a bus or a motorcycle) is described, which comprises the control unit described in this document.

According to a further aspect, a method for operating a hybrid drive is described, the hybrid drive comprising an internal combustion engine and an electrical machine for driving a primary shaft of a starting clutch. The method includes determining whether the internal combustion engine and / or the electric machine are used or should be used to drive the primary shaft for a starting maneuver. Furthermore, depending on the drive module used, the method includes setting the speed of the primary shaft for the starting maneuver.

According to a further aspect, a software (SW) program is described. The SW program can be set up to be executed on a processor (e.g. on a control device of a vehicle) and thereby to carry out the method described in this document.

According to a further aspect, a storage medium is described. The storage medium can comprise a software program which is set up to be executed on a processor and thereby to carry out the method described in this document.

It should be noted that the methods, devices and systems described in this document can be used both alone and in combination with other methods, devices and systems described in this document. Furthermore, any aspect of the methods, devices and systems described in this document can be combined with one another in a variety of ways. In particular, the features of the claims can be combined with one another in a variety of ways.

• 1 einen beispielhaften Hybridantrieb eines Fahrzeugs;
• 2 beispielhafte Kennlinien zur Einstellung der Drehzahl eines Antriebsmoduls; und
• 3 ein Ablaufdiagramm eines beispielhaften Verfahrens zum Betrieb eines Hybridantriebs.

The invention is described in more detail below with the aid of exemplary embodiments. Show

• 1 an exemplary hybrid drive of a vehicle;
• 2nd exemplary characteristic curves for setting the speed of a drive module; and
• 3rd a flow diagram of an exemplary method for operating a hybrid drive.

As stated at the beginning, the present document deals with the reliable and gentle operation of a hybrid drive of a vehicle, in particular in the context of a starting situation or a starting maneuver. In this context shows 1 a block diagram of an exemplary hybrid drive of a vehicle 100 . The hybrid drive includes an internal combustion engine 101 and an electrical machine 102 that can be used individually or together to create a drive torque for the vehicle 100 to generate. The internal combustion engine 101 and the electrical machine 102 are arranged so that the drive motor 101 , 102 generated moments (via the respective drive motor 101 , 102 assigned translation (e.g. via a pre-translation of the electrical machine 102 ) and / or via a common gear ratio) to a total drive torque, the total drive torque typically via a clutch 108 , in particular via a starting clutch, via a transmission 104 and possibly via a differential lock 105 on one or more wheels 106 of the vehicle 100 provided. The coupling 108 can in the gearbox 104 be integrated. In this case, the secondary shaft 123 the clutch 108 inside the gearbox 104 be arranged (and / or possibly the output shaft 124 of the transmission 104 correspond).

In particular, it is in 1 shown hybrid drive around a parallel hybrid drive, in which the drive torques of the two motors or drive modules 101 , 102 directly or via the respective drive motor 101 , 102 assigned translation additively to the transmission input shaft 123 (or on the secondary shaft 123 the starting clutch 108 ) act. Furthermore shows 1 a disconnect clutch 103 with which the transmission 104 from the internal combustion engine 101 can be decoupled and / or with which the internal combustion engine 101 and the electrical machine 102 can be decoupled from each other.

The vehicle 100 further comprises a control unit 110 (e.g. an engine control unit) that is set up, a requested total drive torque 114 to determine. The requested total drive torque 114 can, for example, via an accelerator pedal (in particular via the deflection of the accelerator pedal) and / or via an adjustment of the transmission 104 be specified by a driver of the vehicle. For example, a driver can actuate or deflect the accelerator pedal by an increased total drive torque 114 to request.

The control unit 110 is further set up, the requested total drive torque 114 in a first moment 111 (for the internal combustion engine 101 ) and in a second moment 112 (for the electrical machine 102 ) to divide. In other words, the control unit 110 can be set up the internal combustion engine 101 and the electrical machine 102 depending on a requested total drive torque 114 to operate.

The internal combustion engine 101 and the electrical machine 102 can be operated as a function of characteristic data, in particular at a suitable speed of the internal combustion engine depending on the driving situation 101 and / or the electrical machine 102 to effect. The combustion engine 101 and the electrical machine 102 typically operated so that both drive motors 101 , 102 directly or via the respective drive motor 101 , 102 assigned translation at the input and output of the disconnect clutch 103 provides the same speed to the disconnect clutch 103 to be able to separate or close in a flexible manner. In particular, in a parallel hybrid vehicle 100 with automated transmission 104 (e.g. dual clutch transmission or automatic transmission) regardless of the current drive form of the hybrid drive (electric or combustion engine) the same starting speed strategy (ie the same time course of the speed) and the same starting speed for the internal combustion engine 101 and for the electrical machine 102 be used.

With an internal combustion engine 101 Typically, speeds below a certain limit speed (for example below the idling speed) cannot be used, in particular in order to enable stable and / or acoustically advantageous operation. Thus the wave points 121 of the internal combustion engine 101 typically a basic speed for a starting maneuver 211 on (see 2nd ), which cannot be undercut. As a result, the primary wave typically also points 122 the starting clutch 108 the basic speed 211 on. On the other hand, the output shaft 124 of the transmission 104 as well as the secondary wave 123 the starting clutch 108 At the start of a start-up maneuver, the speed is typically zero.

Consequently, there is a relatively high speed difference between the speed of the primary shaft during a start-up maneuver 122 and the secondary wave 123 the starting clutch 108 in front. This speed difference leads to a relatively high temperature input into the starting clutch 108 . This can also lead to an increase in the temperature of the transmission oil circuit, for example if the starting clutch 108 in the transmission 104 is integrated. The consequence of this can be impairments and / or operational restrictions of the starting clutch 108 and / or the transmission 104 be.

2nd shows an exemplary characteristic 201 for the speed of the internal combustion engine 101 as a function of the deflection of the vehicle's accelerator pedal 100 and / or as a function of the torque to be produced. As from the characteristic 201 can be seen, the speed of the internal combustion engine falls below 101 not the base speed 211 . The characteristic 201 for the internal combustion engine 101 can also be used for the electrical machine during a start-up maneuver 102 are used to synchronize the speed of internal combustion engines 101 and electrical machine 102 to enable. This enables flexible use of the internal combustion engine 101 and / or electrical machine 102 . In particular, this can be done in a flexible manner between the internal combustion engine 101 and electrical machine 102 change.

On the other hand, the electrical machine could 102 from a technical and / or acoustic point of view for a starting maneuver to be operated at a speed which is lower than the basic speed 211 is. In particular, the characteristic curve, for example 202 used to control the speed of the primary shaft during a start-up maneuver 122 synchronous with the speed of the secondary shaft 123 to increase. So the heat input into the starting clutch 108 be avoided or at least reduced during a starting maneuver.

The starting speed can thus be decoupled during an internal combustion engine starting maneuver and the starting speed during an electric starting maneuver. In particular, a lower starting speed can be used for an electric starting maneuver than for an internal combustion engine starting maneuver.

Alternatively or in addition, the separating clutch can be used 103 between the wave 121 of the internal combustion engine 101 and the wave 122 of the electrical machine 102 can be used as an additional torque transmission element during a starting maneuver. In particular, the disconnect clutch 103 used to make a speed difference between the shaft 121 of the internal combustion engine 101 and the wave 122 of the electrical machine 102 intercept at least temporarily. The temperature input brought about is typically less than the temperature input into the starting clutch 108 because that is via the disconnect clutch 103 The transmitted (first) torque is typically smaller than that via the starting clutch 108 total drive torque transmitted.

The electrical machine 102 can be used, for example, for a starting maneuver according to the characteristic curve 203 out 2nd operate. In particular, the electrical machine can also 102 at the start of a starting maneuver with a basic speed 213 are operated that are greater than zero but less than the basic speed 211 of the internal combustion engine 101 is. As a result, temperature is entered into the starting clutch during a starting maneuver 108 which, however, is less than the temperature input when using the basic speed 211 of the internal combustion engine 101 is.

If for the starting maneuver in addition to the electrical machine 102 the internal combustion engine 101 with the basic speed 211 is used, the temperature is also entered into the clutch 103 , which is the difference between that on the input side and that on the output side of the separating clutch 103 effective speeds by the internal combustion engine 101 (input side) or from the electrical machine 102 (on the output side) depends.

The total temperature input in both clutches 103 , 108 is, however, less than the temperature input when using the basic speed 211 of the internal combustion engine 101 for both drive modules 101 , 102 would be present because that is on the disconnect clutch 103 transmitted first torque 111 is smaller than that on the starting clutch 108 total torque transmitted 114 . By using different speeds for the internal combustion engine 101 and for the electrical machine 102 can thus the temperature input and thus the load on the one or more couplings 103 , 108 of a hybrid drive can be reduced.

The vehicle 100 can have one or more temperature sensors 107 include, which are set up, temperature data related to the temperature of the starting clutch 108 and / or in relation to the temperature of the disconnect clutch 103 capture. Alternatively or additionally, the temperature data can be based on a temperature model of the starting clutch 108 and / or the disconnect clutch 103 be determined. The speed of the internal combustion engine 101 and / or the electrical machine 102 during a start maneuver can be set depending on the temperature data. For example, a relatively low starting speed of the electrical machine 102 used when the temperature data indicate that the starting clutch 108 has a relatively high temperature (by a further temperature entry into the starting clutch 108 to avoid or reduce due to the starting maneuver).

As an alternative or in addition, the form of drive for a starting maneuver can be selected as a function of the temperature data. In particular, depending on the temperature data, it can be determined whether the starting maneuver is purely electrical, purely internal combustion engine or with a combined operation of an internal combustion engine 101 and electrical machine 102 he follows. At a relatively high temperature of the starting clutch 108 can be determined, for example, that the electrical machine 102 is at least partially involved in a start-up maneuver (with a relatively low speed) (around the temperature entry into the start-up clutch 108 to reduce).

It can thus efficiently reduce the temperature input into the starting clutch 108 and / or in the oil circuit of the transmission 104 can be achieved if a suitable starting strategy for a starting maneuver is selected depending on a current situation.

3rd shows a flow diagram of an exemplary method 300 for operating a hybrid drive, in particular a parallel hybrid drive. The hybrid drive includes an internal combustion engine 101 and an electrical machine 102 that are set up, the primary wave 122 a starting clutch 108 to drive. The starting clutch can 108 in a gearbox 104 of the hybrid drive. The secondary wave 123 the starting clutch 108 can, possibly via a gear 104 , with one or more drive wheels 106 of a vehicle 100 be connected. The procedure 300 can by a control unit 110 of the vehicle 100 and / or the hybrid drive.

The procedure 300 involves determining 301 whether the combustion engine for a start-up maneuver 101 and / or the electrical machine 102 to drive the primary shaft 122 be used or should be used. The form of drive used for a starting maneuver can be based on temperature data in relation to the temperature of the starting clutch 108 be determined. As an alternative or in addition, the state of charge of the electrical energy store can 109 to provide electrical energy for the operation of the electrical machine 102 be taken into account when selecting the drive form for a starting maneuver. As an alternative or in addition, a current driving situation can be recognized, and the form of drive for a starting maneuver can be determined as a function of the current driving situation. The current slope of the road during the starting maneuver, the fact whether the vehicle is in motion, for example, can be elements of the driving situation 100 operated or not with a trailer and / or the mass of the vehicle 100 be determined.

The procedure also includes hiring 302 the speed of the primary shaft 122 for the starting maneuver depending on the selected drive form. Different speeds or different speed profiles can be set for the starting maneuver, depending on whether the electrical machine 102 alone, or the internal combustion engine 101 alone or the electric machine 102 and the internal combustion engine 101 in combination to drive the primary shaft 122 the starting clutch 108 be used. So the load and wear of a starting clutch 108 be reduced.

The present invention is not restricted to the exemplary embodiments shown. In particular, it should be noted that the description and the figures are only intended to illustrate the principle of the proposed methods, devices and systems.

Claims (10)

Control unit (110) for a vehicle (100), which comprises an internal combustion engine (101) and an electrical machine (102) for driving a primary shaft (122) of a starting clutch (108); the control unit (110) being set up, - to determine whether the internal combustion engine (101) and / or the electrical machine (102) are used to drive the primary shaft (122) for a starting maneuver of the vehicle (100); and - as a function of setting a speed of the primary shaft (122) for the starting maneuver. Control unit (110) according to Claim 1 , wherein - a first speed (211) of the primary shaft (122) is set if only the internal combustion engine (101) is used to drive the primary shaft (122), - a second speed (213) of the primary shaft (122) is set if at least partially the electrical machine (102) is used to drive the primary shaft (122); and - the second speed (213) is lower than the first speed (211). Control unit (110) according to one of the preceding claims, wherein - The internal combustion engine (101) has an idling and / or basic speed (211), which should not be undercut; and - The speed of the primary shaft (122) for the starting maneuver is set lower than the idling and / or basic speed (211) when the electrical machine (102) is used at least partially to drive the primary shaft (122). Control unit (110) according to one of the preceding claims, wherein from the beginning of the starting maneuver a synchronous with a speed of a secondary shaft (123) of the starting clutch (108) increasing speed of the primary shaft (122) of the starting clutch (108) is set, if only the electric machine (102) is used to drive the primary shaft (122). Control unit (110) according to one of the preceding claims, wherein - The internal combustion engine (101) and the electrical machine (102) can be coupled to one another via a separating clutch (103); - A first speed (211) of the internal combustion engine (101) and a second speed (213) of the primary shaft (122) are set when both the internal combustion engine (101) and the electrical machine (102) are used to drive the primary shaft (122) will; - The first speed (211) is greater than the second speed (213), and - The speed difference between the first speed (211) and the second speed (213) is intercepted by the clutch (103). Control unit (110) according to one of the preceding claims, wherein the control unit (110) is set up - determine temperature data in relation to a temperature of the starting clutch (108); and - Depending on the temperature data, to determine whether the internal combustion engine (101) and / or the electrical machine (102) are used to drive the primary shaft (122) for the starting maneuver of the vehicle (100); and or - Depending on the temperature data, set the speed of the primary shaft (122) for the starting maneuver. Control unit (110) according to Claim 6 , wherein the control unit (110) is set up to - determine that the electrical machine (102) is used at least partially to drive the primary shaft (122) when the temperature data indicate a relatively high temperature of the starting clutch (108); and / or - to determine that the internal combustion engine (101) is used to drive the primary shaft (122) at least in part if the temperature data indicate a relatively low temperature of the starting clutch (108). Control unit (110) according to one of the Claims 6 to 7 , wherein the control unit (110) is set up to - set a relatively low rotational speed of the primary shaft (122), in particular at the beginning of the starting maneuver, when the temperature data indicate a relatively high temperature of the starting clutch (108); and / or - to set a relatively high speed of the primary shaft (122), in particular at the beginning of the starting maneuver, when the temperature data indicate a relatively low temperature of the starting clutch (108). Control unit (110) according to one of the preceding claims, wherein the control unit (110) is set up - Determine a first torque (111) to be provided for the starting maneuver by the internal combustion engine (101) on the primary shaft (122), and / or - To determine a second torque (112) to be provided for the starting maneuver by the electrical machine (102) on the primary shaft (122), and - Adjust the speed depending on the first torque (111) and / or the second torque (112). Method (300) for operating a hybrid drive, the hybrid drive comprising an internal combustion engine (101) and an electrical machine (102), which are set up to drive a primary shaft (122) of a starting clutch (108); the method comprising (300) - Determining (301) whether the internal combustion engine (101) and / or the electrical machine (102) are used for driving the primary shaft (122) for a starting maneuver; and - Depending on this, setting (302) a speed of the primary shaft (122) for the starting maneuver.

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