DE102010031029A1 - Drive assembly for vehicle e.g. wheeler loader, has brake device coupled with element of planetary gears connected with electrical machine, and claw shift member provided to bypass starting element - Google Patents

Abstract

The assembly has an electro-dynamic starting element designed as planetary gears (4), where a combustion engine (1), an electrical machine (5) and a gearbox (2) are coupled to an element (6) i.e. sun wheel, of the planetary gears such that a moment support is temporarily provided at the starting element over the electrical machine. A brake device (9) i.e. controllable frictional lamella brake element, is coupled with the element of the planetary gears connected with the electrical machine. A claw shift member (10) is provided for bypassing the starting element. An independent claim is also included for a method for executing a starting process of a drive assembly with an electro-dynamic starting element.

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.

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 removably 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 at least one braking device and with a gearbox and an electrodynamic starting element, which is designed as a planetary gear, wherein the internal combustion engine, the electric machine and the gearbox each with an element of Are coupled planetary gear so that a torque support on the starting element is at least partially or temporarily provided over the electric machine. According to the invention, the braking device is coupled to the element of the planetary gear connected to the electric machine for torque support, at least one claw switching element being provided 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, on the one hand, the braking device which can be controlled with regard to the transmission capability are provided on the starting element and, on the other hand, the jaw switching element is provided for possible bridging after starting.

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 is connected to the one hand with the starting element and on the other hand arranged fixed to the housing. However, it is also possible to use other frictional switching elements, such as friction clutches or the like, as braking devices that can apply the control of a requested torque required for torque support.

As a lock-up clutch is preferably an unsynchronized shift claw or used in the closed state after starting a connection between the engine and the element of the planetary gear, which is also coupled to the electric machine.

The object underlying the invention is also achieved by a method for performing a starting operation, 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. According to the invention, the torque support on the starting element depending on the required Abstützmomentes at least temporarily or partially via the control of a desired torque of an electric machine and / or at least temporarily or partially by driving a target torque of a braking device are applied, wherein after starting a jaw switching element for Bridging the starting element can be closed.

In this way, a method is proposed, which allows 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 an electric motor limited in power, in optionally a braking torque for torque support or support is used.

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 required target torque of the braking device and the electric machine is determined for support in the context of the inventive method, so that the desired drive torque is available throughout the journey. When using the braking device for torque assistance or torque support, there is the advantage that the torque acting as a drive of the internal combustion engine is not reduced.

The proposed method also includes the operating case in which the braking device is controlled in such a way that the nominal torque of the braking device assumes approximately zero and the supporting torque is applied solely by actuating the electric machine via the requested nominal electrical torque, if at the beginning of a desired starting process the condition is recognized that the necessary support torque is smaller than the maximum possible torque of the electric machines with the switching claw element open.

However, if it is detected at the beginning of the starting process to be carried out that the necessary support torque is greater than the maximum possible torque of the electric machine can be provided in the context of the inventive method that the electric machine is controlled such that as requested desired torque of the electric machine, the maximum possible torque is applied, wherein the still missing residual torque is applied for support by driving the braking device. Thus, the requested support load is applied by the brake device and the electric machine together.

If, during the further starting process, it is recognized independently of the previous operating state that the necessary supporting torque is less than or equal to the maximum possible torque of the electric machine, the braking device can be opened or remain open and the electric machine can apply the supporting moment alone until a synchronization point is reached. The synchronization point corresponds to the time at which the speed of the electric machine and the transmission input speed and the engine speed are identical. As soon as the synchronization point is reached, the shifting claw for bridging the starting element can be closed and the torque of the electric motor can be reduced.

However, should it also be recognized during the further start-up process that the necessary support torque is greater than the maximum possible torque of the electric machine, the electric machine can not apply the desired moment alone to the synchronization point, since the reverse-rotating electric machine is close to the speed reversal and apply hardly any moment can. In the context of the method according to the invention can therefore be provided that the electric machine is decelerated via the braking device and finally braked, so that the starting process is terminated. As a result, the requested transmission input torque is maintained throughout the start-up process, but the speed of the internal combustion engine increases. The electrodynamic starting element is used quasi in this state as Vorschaltgetriebe to the main transmission. In this way, the changeover can be done earlier than usual in the manual transmission.

If, for example, it is detected at a later time after the start-up process has ended, that a lower load requirement exists, so that the maximum possible torque of the electric machine is greater than the necessary support torque, the load transfer can again take place from the braking device to the electric machine, so that the target torque of the braking device is reduced to zero and the electric machine actively synchronize the shift dog element can. Subsequently, the shift dog can be closed to realize a bridging of the starting element.

In the event that no lower load request is requested after the start of the starting process and is not expected, the closing of the shift dog can be prepared by a motor intervention. The engine intervention should be done at a time when there is no loss of comfort or function for the driver. However, an engine intervention should absolutely or immediately be carried out if, for example, it is detected that the state of charge of the battery assumes a critical value or that the highest gear is already engaged in the manual transmission. Other conditions may be set to perform engine intervention to prevent critical driving conditions.

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 starting operation with low drive torque according to the method of the invention;

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

3A a diagram with speed curves during a start-up process with high drive torque according to the method of the invention; and

3B a diagram with torque curves during the starting process according to 3A ,

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 for bridging the starting element after the starting a claw switching element 10 intended. With the claw switching element 10 can the internal combustion engine 1 or the drive shaft of the internal combustion engine 1 and the first element 6 of the planetary gear 4 be coupled. The braking device 9 is designed as a controllable, frictional lamella 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 and the electric machine 5 or applied individually.

In 2A and 2 B are exemplified speed curves and torque curves in a starting operation with low drive torque, while in the 3A and 3B Exemplary speed curves and torque curves are shown in a startup with high torque.

In the 2A and 3A are each the progressions of the rotational 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 the 2 B and 3B in each case the curves of the maximum possible torque M_EM_max of 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 the maximum possible torque M_B1_max the braking device 9 as well as the maximum possible torque M_EM_max of the electric machine 5 are shown over time t during a startup process.

In particular, goes from the in the 2A . 2 B . 3A and 3B indicated courses exemplified the operation of the invention for controlling the braking device and the claw switching element during a journey forth. A starting operation from the standstill of the vehicle begins at time t1 and ends in accordance with 2A and 2 B when the shift dog element is closed 10 to the synchronization point t4 or according to the 3A and 3B by stalling the electric machine 5 using the braking device 9 at time t3.

According to 2a and 2 B During the starting operation with low drive torque between the times t1 and t2, the requested support torque M1_soll with open shift claw element 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 the requested support torque M1_soll is reached at time t2, while the desired torque M_B1_soll of the braking device 9 continuously decreases until it becomes zero at time t2.

Thus results between the times t1 and t2 a load change of a common load transfer of braking device 9 and electric machine 5 to a sole load transfer by the electric machine 5 , which is present at time t2.

At time t2 it is decided that the electric machine 5 capable of the necessary supporting M1_soll without the operation of the braking device 9 Apply, as from the course of the speed n1 of the electric machine 5 according to 2A it can be seen that the backward rotating electric machine 5 is sufficiently removed from the speed reversal at time t3 and thus can still apply sufficient moment to apply the requested support torque M1_soll between the times t2 and t4 alone. As a result, identical courses of required supporting moment M1_setpoint and the setpoint torque M_EM_setpoint of the electric machine result between these times 5 ,

From the speed curves according to 2A In turn, it results that at time t4 the synchronization point is reached at which both the rotational speed n1 of the electric machine 5 and the transmission input speed n2 and the engine speed n3 are identical. As a result, at time t4, the shift dog 10 be closed and thus the startup process is terminated. Subsequently, the target torque of the electric machine 5 degraded until it assumes the value zero at time t5.

According to 3a and 3B is the requested support torque M1_soll with open switching claw element during the starting process with higher drive torque between times t1 and t2 10 both via the electric machine 5 as well as the braking device 9 applied, as in the starting process with a lower driving torque according to the 2A and 2 B , As a result, essentially the same courses occur between the times t1 and t2, apart from the absolute values as a result of the different supporting moments M1_soll.

At time t2 according to the 3A and 3B results from the speed curve n1 of the electric machine 5 that the electric machine 5 due to its low negative speed near the speed reversal can not apply the requested support torque M1_soll to the synchronization point, see t4 according to 2A and 2 B to bring about. Therefore, the target torque M_EM_soll of the electric machine 5 At time t2 reduced to zero and at the same time the target torque M_B1_soll the braking device 9 increased to apply the requested support M1_soll. As a result, the electric machine 5 decelerated, wherein at time t3, the electric machine 5 through the closed brake device 9 is braked firmly. This results in a load transfer from the electric motor from time t2 5 on the braking device 9 , wherein the starting process is completed at time t3.

By stalling the electric machine 5 and thus by holding the sun gear or the first elements 6 of the planetary gear 4 the electrodynamic starting element acts as a primary gear to the main gearbox 2 and thereby the engine speed n3 of the internal combustion engine increases 1 after time t3 on, like out 3A is apparent. By increasing the engine speed n3 takes place in the manual transmission 2 the upshift earlier. The switching points will be according to the conversion of the combustion engine 1 to the transmission input by the factor for example i0 / (1 - i0) preferred.

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

Claw switching element or claw

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_B1_max

maximum possible moment of the braking device

io

Translation of the manual transmission

t1

Start of the starting process

t2

End of the moment support by the braking device

t3

Speed reversal at the electric machine

t4

synchronization point

t5

Time at which the electric machine does not apply a moment

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 (13)

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 ) are coupled so that a torque support on the starting element at least temporarily via the electric machine ( 5 ) is provided, 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, wherein for bridging the starting element at least one claw switching element ( 10 ) is provided. 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 the form-locking claw switching element ( 10 ) on the one hand with the internal combustion engine ( 1 ) and on the other hand coupled to the starting element. A method for performing a starting operation in a drive assembly with an electrodynamic starting element, in particular according to one of the preceding claims, wherein for starting a requested support torque (M1_soll) is applied to the starting element, characterized in that the torque support on the starting element depending on the requested support torque at least temporarily via the activation of a setpoint torque (M_EM_soll) of an electric machine ( 5 ) and at least temporarily via the activation of a desired torque (M_B1_soll) of a braking device ( 9 ) is applied, wherein after starting a claw switching element ( 10 ) can be closed to bridge the starting element. A method according to claim 4, characterized in that when at the beginning of the starting process approximately at a time (t1) is detected that the required support torque (M1_soll) is less than or equal to the maximum possible torque (M_EM_max) of the electric machine ( 5 ), the electric machine ( 5 ) is controlled in such a way that the required nominal electrical torque (M_EM_soll) corresponds approximately to the necessary support torque (M1_soll) and the braking device ( 9 ) remains open or is opened. A method according to claim 4, characterized in that, if at the beginning of the starting process approximately at a time (t1) is detected that the necessary support torque (M1_soll) is greater than the maximum possible torque (M_EM_max) of the electric machine ( 5 ), the electric machine ( 5 ), the requested desired torque (M_EM_soll) is approximately the maximum possible torque (M_EM_max) of the electric machine ( 5 ) and the braking device ( 9 ) is controlled such that the requested desired torque (M_B1_soll) of the braking device ( 9 ) about the value of the difference between the required support torque (M1_soll) and the maximum possible torque (M_EM_max) of the electric machine ( 5 ) corresponds. A method according to claim 6, characterized in that, if it is detected during the starting process approximately at a time (t2) that the necessary support torque (M1_soll) is less than or equal to the maximum possible torque (M_EM_max) of the electric machine ( 5 ), the braking device ( 9 ) is opened or remains open at the time (t2), so that the requested setpoint torque (M_B1_soll) of the braking device ( 9 ) assumes or maintains the value zero and at the same time the electric machine ( 5 ) is controlled such that the desired torque (M_EM_soll) of the electric machine ( 5 ) to a synchronization point (t4), in which substantially equal speed between the rotational speed (n1) of the electric machine ( 5 ), the transmission input speed (n2) of the engine speed (n3) corresponds approximately to the necessary support torque (M1_soll). Method according to Claim 7, characterized in that, when the synchronization point (t4) has reached the claw switching element ( 10 ) is closed for bridging the starting element and that the requested desired torque (M_EM_soll) of the electric machine ( 5 ) is degraded. Method according to one of claims 4 to 6, characterized in that, if it is detected during the starting process about at a time (t2) that the necessary support torque (M1_soll) is greater than the maximum possible torque (M_EM_max) of the electric machine ( 5 ), the braking device ( 9 ) is controlled in such a way that the necessary support torque (M1_soll) the desired torque (M_B1_soll) of the braking device ( 9 ) corresponds. Method according to claim 9, characterized in that the electric machine ( 5 ) after time (t2) at about time (t3) by the braking device ( 9 ) is completely braked, after which the desired torque (M_B1_soll) of the braking device ( 9 ) about the maximum possible torque (M_B1_max) of the braking device ( 9 ), which is greater than the requested support moment (M1_soll). Method according to one of claims 9 or 10, characterized in that if after the time (t3) is recognized due to a lower load requirement that the necessary support torque (M1_soll) is less than or equal to the maximum possible torque (M_EM_max) of the electric machine ( 5 ), the electric machine ( 5 ) is controlled in such a way that the required supporting moment (M1_soll) the desired torque (M_EM_soll) of the electric machine ( 5 ), so that the claw switching element is actively activated by the electric motor ( 5 ) and then the claw switching element ( 10 ) is closed to bridge the starting element. Method according to one of claims 9 or 10, characterized in that, if after the time (t3) is detected that the necessary support torque (M1_soll) continues to be greater than the maximum possible torque (M_EM_max) of the electric machine ( 5 ), an engine intervention to reduce the necessary support torque (M1_soll) is performed. A method according to claim 12, 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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