DE102010031026A1 - Drive arrangement for vehicle, has combustion engine, electric machine, braking unit, shift gearbox and electrodynamic starting element that is formed as planetary gear - Google Patents

Abstract

The drive arrangement has a combustion engine (1), an electric machine (5), a braking unit (9), a shift gearbox (2) and an electrodynamic starting element that is formed as planetary gear (4). The braking unit is coupled with an element (6) of the planetary gear for torque support, where the element is connected with the electric machine. An independent claim is also included for a method for executing a starting process in a drive arrangement.

Description

The present invention relates to a drive arrangement and a method for performing a starting operation according to the closer defined in the preamble of claim 1 and 4, respectively.

For example, from the document DE 199 34 696 A1 is an electrodynamic drive system for a vehicle with a prime mover and a manual transmission and a planetary gear known as a starting element. A ring gear of the planetary gear is connected to the prime mover and the planet carrier is connected to the gearbox. Furthermore, a sun gear of the planetary gear is coupled to an electric motor, so that a total of a wear-free starting element for the vehicle is realized. In order to provide the requested drive torque at the transmission input via the internal combustion engine, it is necessary that the sun gear of the planetary gear is supported by the electric motor accordingly. In the known electrodynamic drive system there is the disadvantage that in the design of the performance of the electric motor, the sole application of the high support torque must be taken into account in the planetary gear, so that a costly, equipped with a correspondingly high efficiency electric motor in the known drive system is necessary.

Furthermore, from the document DE 10 2007 004 461 A1 a hybrid drive arrangement is known in which an internal combustion engine and a transmission with variable ratio and an electric machine are provided in the drive train, wherein the electrical machine is connected on the output side via a planetary gear to the drive train. At least one brake is provided on the electric machine, so that a required support torque is generated on the drive train via the electric machine. With the brake can be carried out in a disadvantageous way only to a standstill of the electric machine, so that the brake applies no support in a complete synchronization of the starting element.

In addition, from the document DE 10 2005 039 928 A1 a method for controlling or regulating an electrodynamic starting element when starting known. In the known method, it is provided that an occurring difference torque between the desired transmission input shaft torque and the transmission input shaft torque actually set via the electric motor is taken over by a clutch which releasably connects the rotor of the electric motor to the internal combustion engine. However, when using the so-called lock-up clutch for assistance, the torque transmittable from the engine to the transmission input decreases. As a result, only a limited drive torque can be displayed.

The present invention is based on the object propose a drive assembly and a method for performing a starting operation in a drive assembly, which enable a control of a starting operation with the highest possible drive torque with limited electromotive support torque.

This object is achieved by the features of claim 1 and 4, wherein further advantageous embodiments of the respective subclaims and the drawings.

It is proposed a drive arrangement for a vehicle with an internal combustion engine, with at least one electric machine and with at least one braking device and with a manual transmission and an electrodynamic starting element, which is designed as a planetary gear, wherein the internal combustion engine, the electric machine and the transmission each with a different element the planetary gear are coupled, so that a torque support is provided on the starting element. According to the invention, the braking device is coupled to the element of the planetary gear connected to the electric machine for moment support, at least one frictional coupling element being provided for further torque support and / or for possible bridging of the starting element.

In this way, a drive arrangement with an electrodynamic starting element is proposed in which the maximum possible transmission input torque or drive torque can also be continuously applied during the starting process, even with a limited electric machine with regard to the available power. For this purpose, the controllable with respect to the transmission capacity braking device and the controllable with respect to the transfer coupling means are provided on the starting element, wherein advantageously the coupling device can also be used to bridge the starting element after starting as needed.

Preferably can be used as a braking device with respect to an attachable braking torque controllable, frictional disk brake element or frictional switching element, which on the one hand connected to the starting element and on the other hand arranged fixed to the housing is. However, it is also possible to use other frictional switching elements or the like, as braking devices that can apply the driving of a requested target torque for torque support.

As a coupling device is preferably a frictional coupling element, such. B. a multi-plate clutch or the like used, which can apply as needed alone or together, for example with the electric machine and / or with the braking device, a torque support on the starting element. If, for example, a bridging of the starting element is desired after the end of the starting operation, this can be achieved by the coupling device acting as a bridging clutch in which the connection created between the internal combustion engine on the one hand and the starting element on the other hand is closed by the coupling device.

The object underlying the invention is also achieved by a method for performing a starting process, in particular in the above-described drive arrangement with an electrodynamic starting element or in other drive arrangements, wherein for starting a requested support torque is applied to the starting element at least partially by electric motor. According to the invention, the electromotive torque support on the starting element can be supported at least temporarily or partially via the activation of a desired torque of a braking device and at least temporarily or partially via the activation of a desired torque of a coupling device.

In this way, a method is proposed, which enables a start over the electrodynamic starting element without closing, wherein the maximum available drive torque or transmission input torque for driving the vehicle, in particular a commercial vehicle, can also be applied continuously with a limited in power electric machine. This is made possible, in particular, by the fact that, depending on requirements, it is possible in part to realize both torque support by controlling a braking device and by driving a clutch device if the required supporting torque is greater than the maximum possible torque of the electric machine. The combined use of brake and clutch results in an optimized starting process with the invention Antriebsanord voltage.

The necessary support torque to the planetary gear as a starting element results arithmetically from the desired or requested by the driver drive torque, which in turn corresponds to the transmission input torque. Depending on the required Abstützmoment the respective target torque of the braking device and the electric machine and the coupling device is determined for support in the context of the inventive method, so that the desired drive torque is available throughout the journey.

If it is assumed that the requested support torque is greater than the maximum possible torque of the electric machine, which is the case in particular with drive assemblies with electric machines with limited performance, the electric machine is driven during the entire starting process such that the electric machine the maximum possible torque for Supports apply.

Preferably can be provided to support the electromotive support that at the beginning of the starting process, the braking device is used to apply a differential torque between the requested support torque and the applied by the electric machine target torque. For this purpose, the braking device can be controlled accordingly.

For example, may be provided in the context of a next development of the present invention that in response to a predetermined limit of the speed of the electric machine or the speed gradient, a load transfer from the brake device to the coupling device for applying a necessary differential torque is performed for torque support. If no speed threshold is used, can be calculated from the speed gradient along the speed curve of the electric machine, how long it takes until the time until the speed of the electric machine takes the value zero. The load transfer is started when a limit value for the necessary time for carrying out the load transfer is reached.

It is also possible that in the method according to the invention in the context of torque support or support at the beginning of the coupling device and then the braking device or are used together. It has been shown, however, that when starting due to the backward rotating electric machine, the differential speed of the clutch device is always higher in terms of magnitude than at the brake device, so that the friction loss at the clutch device is also higher. Accordingly, it is advantageous if at the beginning of the starting process, the braking device due to the lower Friction power is used while the coupling device is used for support after the speed reversal in the electric machine.

When using the braking device for torque assistance or support, it is advantageous that the moment acting as a drive of the internal combustion engine is not reduced. When using the coupling device, the torque to be transmitted is to be chosen so that despite all this the requested drive torque is reached at the transmission input.

According to a next embodiment of the invention can therefore be provided that a load transfer from the braking device to the coupling device begins when a predetermined limit value is reached and is completed when the rotational speed of the electric machine approximately assumes the value zero. However, it is also possible that the load transfer is carried out later or earlier. During load transfer, the process according to the invention results in an overlap of the support of the brake device and the clutch device.

In the method according to the invention, the torque support via the clutch device can preferably take place until the synchronization point is reached, in which there is equal speed between the rotational speed of the electric machine, the transmission input rotational speed and the engine speed rotational speed of the internal combustion engine. Thereafter, the starting operation can be terminated by closing the coupling device for bridging the starting element.

If, for example, it is recognized that the necessary support torque is greater than the possible desired torque of the clutch device, the clutch device can remain open and instead the electric machine is braked by the brake device, wherein the bridging of the starting element is performed by closing the clutch device only at a later time if there is a lower load requirement.

It is also possible for a motor engagement to be performed to reduce the load request in order then to realize the bridging of the starting element by closing the coupling device. For example, such engine intervention can be performed immediately when critical operating conditions are detected, such as a critical state of charge of the energy storage of the electric machine or when it is detected that the transmission is already in the highest gear.

The method proposed according to the invention can preferably be used in the likewise proposed drive arrangement, in which a hydrodynamic torque converter is replaced by the electrodynamic starting element. But there are also other applications conceivable.

The present invention will be further explained with reference to the drawings. Show it:

1 a schematic view of a possible embodiment of a drive arrangement according to the invention;

2A a diagram with speed curves during a start-up process with high drive torque according to the method of the invention; and

2 B a diagram with torque curves during the starting process according to 2A ,

In 1 is an example of a drive arrangement for a vehicle, for example for a commercial vehicle, in particular wheel loader or the like, with an internal combustion engine 1 and a manual transmission 2 shown, which with the output 3 the vehicle is drivingly connected. The drive arrangement comprises an electrodynamic starting element, which serves as planetary gear 4 is trained. The planetary gear 4 Must have a Momentüberhöhung between the internal combustion engine 1 and the transmission input of the gearbox 2 represent. This is the support of a moment on the planetary gear 4 required. This is an electric machine 5 , which can be operated as a generator or motor, with a first element 6 , For example, the sun gear, the planetary gear 4 connected while the manual transmission 2 with a second element 7 , z. B. the web of the planetary gear 4 and the internal combustion engine with a third element 8th , For example, the ring gear of the planetary gear 4 are connected. In the illustrated example, the planetary gear 4 a standard translation io from -2 to.

In order to be able to apply the necessary supporting moment M1_soll, in particular when using an electric machine 5 with limited performance, are in the drive assembly according to the invention in addition to the electric machine 5 in addition a braking device 9 and a frictional coupling device 10 provided, wherein the frictional coupling device 10 can also be used to bridge the starting element after the starting process. For this purpose, designed as a multi-plate clutch element coupling device 10 a frictional connection between the internal combustion engine 1 and the first element 6 of the planetary gear 4 or the electric machine 5 produce.

Both the coupling device 10 as well as the braking device 9 are controllable with regard to their transferability. The braking device 9 is designed as a frictionally engaged disk brake element, and on the one hand fixed to the housing and on the other hand according to the invention with the first element 6 of the planetary gear 4 connected, with which also the electric machine 5 is coupled. In this way, the support torque can optionally together by the braking device 9 , the coupling device 10 and the electric machine 5 or applied individually.

In 2A and 2 B For example, speed curves and torque curves are shown during a starting process with low drive torque.

In 2A are the curves of the speed n1 of the electric machine 5 , the transmission input speed n2 and the engine speed n3 of the internal combustion engine 1 shown over the time t during a startup process. While in 2 B the curves of the maximum possible torque M_EM_max the electric machine 5 , the necessary support torque M1_soll, the in the electric machine 5 requested target torque M_EM_soll, the at the braking device 9 requested target torque M_B1_soll and that in the clutch device 10 requested target torque M_K1_soll are shown over the time t with high drive power during a startup.

In particular, goes from the in the 2A and 2 B indicated courses exemplified the operation of the invention for controlling the braking device 9 and the coupling device 10 during a journey. A starting process from the standstill of the vehicle begins at time t1 and ends when the clutch device is closed 10 to the synchronization point t4.

According to 2A and 2 B is the requested support torque M1_soll with open clutch device during startup with high drive torque between times t1 and t2 10 both via the electric machine 5 as well as the braking device 9 applied. The curves of the setpoint torque M_EM_soll and the maximum possible torque M_EM_max of the electric machine 5 are identical between the times t1 and t2, since the electric machine 5 is operated with the maximum possible moment M_EM_max. The course of the desired torque M_B1_soll the braking device 9 results between the times t1 and t2 from the differential torque of requested support torque M1_soll and maximum torque M_EM_max the electric machine 5 , As a result, the setpoint torque M_EM_soll of the electric machine increases 5 continuously until it has reached the requested support torque M1_soll at time t2, while the target torque M_B1_soll of the braking device 9 continuously reduced until it assumes the value zero at time t3.

In the example selected starting process is the coupling device 10 from the beginning at the time t1 until a time t2 opened and thus brings no torque support on. If at time t2, the speed n1 of the electric machine 5 is smaller than a predetermined limit, a load transfer takes place from the braking device 9 on the coupling device 10 , in the way that at time t3, when a speed reversal in the electric machine 5 the braking device takes place 9 is fully opened, so that the torque support together via the coupling device 10 and the electric machine 5 he follows.

As a result, the target torque M_B1_soll of the brake device becomes 9 from the time t2, for example, via a ramp function to the value zero, wherein at the same time, for example, also via a ramp function, the target torque M_K1_soll the clutch device 10 is increased until at time t3 the required differential torque between requested support torque M1_soll and maximum possible torque M_EM_max of the electric machine 5 has reached.

From the time t3, when the values for the rotational speed n1 of the electric machine 5 are greater than zero, the coupling device 10 so controlled that the course of the desired torque M_K1_soll the clutch device 10 from the respective differential torque of requested support torque M1_soll and maximum possible torque M_EM_max of the electric machine 5 results. Finally, when the synchronization point t4 is reached, the coupling device 10 completely closed, so that the starting process is completed. In this way, via the coupling device 10 bridged the starting element. This is in particular due to the course of the setpoint torque M_K1_soll of the clutch device 10 , which after the synchronization point t4 above the requested support torque M1_soll a constant course in the amount of the maximum possible torque of the clutch device 10 when closed.

LIST OF REFERENCE NUMBERS

1

internal combustion engine

2

manual transmission

3

output

4

Planetary gear or starting element

5

electric motor

6

first element of the planetary gear

7

second element of the planetary gear

8th

third element of the planetary gear

9

braking means

10

frictional coupling device

n1

Speed of the electric machine

n2

Transmission input speed

n3

Engine speed of the internal combustion engine

M_EM_max

maximum possible moment of the electric machine

M1_soll

necessary support torque

M_EM_soll

requested torque at the electric motor

M_B1_soll

desired torque requested at the braking device

M_K1_soll

desired torque requested at the coupling device

io

Translation of the manual transmission

t1

Start of the starting process

t2

Start of load transfer

t3

End of the load transfer

t4

synchronization point

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19934696 A1 [0002]
• DE 102007004461 A1 [0003]
• DE 102005039928 A1 [0004]

Claims (15)

Drive arrangement for a vehicle, with an internal combustion engine ( 1 ), with at least one electric machine ( 5 ) and with at least one braking device ( 9 ) as well as with a manual transmission ( 2 ) and with an electrodynamic starting element, which as a planetary gear ( 4 ) is formed, wherein the internal combustion engine ( 1 ), the electric machine ( 5 ) and the manual transmission ( 2 ) each with an element ( 6 . 7 . 8th ) of the planetary gear ( 4 ), so that a torque support is provided on the starting element, characterized in that the braking device ( 9 ) with the with the electric machine ( 5 ) connected element ( 6 ) of the planetary gear ( 4 ) is coupled to the torque support, and that at least one frictional coupling device ( 10 ) is provided for torque support and / or for bridging the starting element. Drive arrangement according to claim 1, characterized in that as a braking device ( 9 ) is provided a controllable, frictional disk brake element. Drive arrangement according to one of the preceding claims, characterized in that as frictional coupling device ( 10 ) a multi-plate clutch is provided, on the one hand with the internal combustion engine ( 1 ) and on the other hand coupled to the starting element. Method for carrying out a starting operation in a drive arrangement with an electrodynamic starting element, in particular according to one of the preceding claims, wherein for starting a requested support torque (M1_soll) is at least partially electromotive applied to the starting element, characterized in that the electromotive torque support on the starting element at least partially via the activation of a desired torque (M_B1_soll) of a braking device ( 9 ) and at least temporarily via the control of a desired torque (M_K1_soll) of a coupling device ( 10 ) is supported. Method according to claim 4, characterized in that the electric machine ( 5 ) is controlled during the starting process such that the requested electrical desired torque (M_EM_soll) the maximum possible torque (M_EM_max) of the electric machine ( 5 ) corresponds. Method according to one of claims 4 or 5, characterized in that the braking device ( 9 ) at the beginning of the starting operation, for example, from a time (t1) is controlled such that the desired torque (M_B1_soll) of the braking device ( 9 ) about the difference between the requested support torque (M1_soll) and the target torque (M_EM_soll) of the electric machine ( 5 ) corresponds. A method according to claim 6, characterized in that a load transfer for torque support of the braking device ( 9 ) on the coupling device as a function of the rotational speed (n1) of the electric machine ( 5 ) or the speed gradient of the speed curve of the electric machine ( 5 ) is carried out. A method according to claim 7, characterized in that the load transfer at the time (t2), at which the predetermined limit value for the rotational speed (n1) or the speed gradient is reached, and at the time (t3), at which the rotational speed (n1) of the Electric machine ( 5 ) is about zero, is completed. A method according to claim 8, characterized in that the desired torque (M_B1_soll) of the braking device ( 9 ) is reduced from the time (t2) to the time (t3) to the value zero, wherein the course of the desired torque (M_K1_soll) of the coupling device ( 10 ) between the time (t2) and the time (t3) in each case from the necessary support torque (M1_soll) minus the maximum possible torque (M_EM_max) of the electric machine ( 5 ) and the respective setpoint torque (M_B1_soll) of the braking device ( 9 ) is determined. A method according to claim 8 or 9, characterized in that approximately from the time (t3), the braking device ( 9 ) is opened and the desired torque (M_K1_soll) of the coupling device ( 10 ) from the difference of the requested desired torque (M1_soll) and the maximum possible torque (M_EM_max) of the electric machine ( 5 ) is determined. Method according to Claim 10, characterized in that, for example, when the synchronization point (t4) is reached, in which there is substantially equal speed between the rotational speed (n1) of the electric machine ( 5 ), the transmission input speed (n2) of the engine speed (n3) is present, the clutch device ( 10 ) is closed to bridge the starting element. A method according to claim 10, characterized in that when it is detected during the starting process that the necessary support torque (M1_soll) is greater than the possible desired torque (M_K1_soll) of the coupling device ( 10 ), the coupling device ( 10 ) remains open and the electric machine ( 5 ) by the braking device ( 9 ) is completely decelerated, wherein the load transfer from the braking device ( 9 ) on the coupling device ( 10 ) is performed for bridging the starting element at a lower load request. A method according to claim 12, characterized in that if after the time (t3) is detected due to a lower load request that the necessary support torque (M1_soll) is less than or equal to the possible target torque (M_K1_soll) of the coupling device ( 10 ), the braking device ( 9 ) and the coupling device ( 10 ) is closed. A method according to claim 12, characterized in that if after the time (t3) is detected that the necessary support torque (M1_soll) continues to be greater than the possible desired torque (M_K1_soll) of the coupling device ( 5 ), an engine intervention to reduce the necessary support torque (M1_soll) is performed. A method according to claim 14, characterized in that an engine intervention is performed immediately when a critical state of charge of the energy storage of the electric machine ( 5 ) or when the manual transmission ( 2 ) is already in the highest gear.

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