DE10232832A1 - Method for starting off in a multiple clutch transmission, in particular in a double clutch transmission - Google Patents

Abstract

As part of the method for starting for a multiple clutch transmission, in particular a double clutch transmission, with an input shaft, an output shaft, with at least two starting clutches and at least two partial transmissions that generate different gears, with each partial transmission being assigned a starting clutch, at least two starting clutches are assigned for starting. 4, 4 '), a gear being engaged in each of the partial transmissions (5, 5') which can be coupled by means of the at least two starting clutches (4, 4 '), so that the thermal load when starting off is applied to at least two clutches (4, 4 ') distributed, the torque at the transmission output resulting from the sum of the clutch torques of the at least two starting clutches (4, 4') with the gear ratios generated in the at least two partial transmissions (5, 5 ').

Description

The present invention relates to a method for starting with a multiple clutch transmission, especially in a double clutch transmission, according to the preamble of claim 1.

 Dual clutch transmissions are off the vehicle technology known. Usually include such transmissions essentially two sub-transmissions different gear pairs, a double clutch with two friction clutches, a drive shaft and a drive shaft and depending on the number of gears positive, unsynchronized clutches. With a dual clutch transmission, the Gears free of load and without interruption of tractive power and without tensioning the switchable gears be since the next Gear to be shifted already in the uncoupled sub-transmission is inserted. To switch, a friction clutch is opened and the second closed accordingly. Based on the same principle the three and multiple clutch transmissions in general.

While a start-up process is one of the friction clutches Drive motor or the drive synchronized with the output speed in such a way that the engine doesn't stall becomes.

According to the state of the art, must a double clutch transmission during a starting process in the first, second or in any gear the friction work of one of the two friction clutches are included. To make this happen both clutches dimensioned accordingly large, since this occurring thermal load is very large.

The DE 100 15 296 A1 discloses a dual clutch transmission in which the two clutches are partially closed when starting. The clutch torque of the first clutch is continuously increased during the start, the clutch torque of the second clutch running towards zero. Only when starting in first gear, both clutches are partially closed, the torque support of the second gear becoming less and less during starting and thus the thermal load on the first clutch increasing more and more. The thermal load is thus only partially reduced.

The present invention lies the task, a method for starting for a multiple clutch transmission, Specify in particular a dual clutch transmission, which enables the thermal load on the starting clutches to reduce. This allows the starting clutches regarding the thermal resilience can be made smaller, which also results in a reduction in costs.

This object is achieved according to the invention solved the features of claim 1. Other variants go from the subclaims.

Accordingly, it is proposed that one Starting process with a multiple clutch transmission at least two and preferably all Use starting clutches. Here, in each case by means of at least two starting clutches that can be coupled to one gear be inserted so that the thermal load when starting distributed over at least two clutches.

The at least two used Clutches are made during of starting over the entire start-up period with a constant torque partially closed. Only shortly before in the clutch of the first gear Differential speed approaches zero, it is opened. The torque reduction in the clutch of the first gear is from the clutch of the second Gangs taken over, so that the total drive torque remains constant. Thus the most possible optimal acceleration process achieved. The final course of this acceleration process results from the accelerator pedal position and the respective driving resistance. Only if the driving resistance is so great that the driving performance the starting process ends only in first gear in first gear and the clutch of second gear is no longer created.

This results in the torque on the transmission output from the sum of the clutch torques at least two starting clutches, each in the at least two sub-transmissions generated gear ratios.

As part of a particularly advantageous variant the invention provides that before the differential speed in the clutch assigned to a first partial transmission with the currently highest transmission ratio assumes the value zero, the clutch assigned to this sub-transmission fully open is, the vehicle with the associated with a second sub-transmission Clutch is accelerated further and at the same time in the first sub-transmission in a higher gear when the gear of the second sub-transmission is switched. Then when this shift is finished, the first sub-transmission associated clutch closed again to the second sub-transmission to support the assigned clutch when starting again.

With a double clutch transmission are therefore during of the starting process, both starting clutches are used simultaneously.

A sensible extension of the start-up process is that the drive motor is included in the control process. The drive motor should when starting from its idle speed only to a low speed, e.g. B. 1200 rpm, with the highest possible torque. At this speed, the drive motor is held until the slipping process in the clutches is completed, that is, until the clutch of the second gear is completely closed. Then the drive motor and thus the prime mover is up to its nominal speed, for. B. 1900 rpm, accelerated. Should the vehicle continue to accelerate after this starting process, the next gear, e.g. B. preparing to change from first to third gear. Before the drive motor reaches its nominal speed in second gear, the load is then transferred from the second gear clutch to the third gear clutch. With this method, the friction of the starting clutch is kept as low as possible.

The invention is illustrated below the attached Figure, which is a schematic diagram of a dual clutch transmission shows closer explained.

In the figure is a double clutch transmission 1 , with a drive shaft 2 , an output shaft 3 , as well as two clutches 4 . 4 ' , each of the two sub-transmissions 5 . 5 ' are assigned, shown schematically. The first partial transmission 5 creates the gears 1 . 3 . 5 . 7 . 9 . 11 as well as the three reverse gears 1R . 2R and 3R , whereas the second sub-transmission 5 ' the aisles 2 . 4 . 6 . 8th . 10 , and 12 generated so that twelve forward gears and three reverse gears can be realized.

For example, in the context of the method according to the invention in the first sub-transmission 5 the first gear and in the second sub-transmission 5 ' the second gear is engaged; According to the procedure presented here, the starting process can be carried out with both clutches 4 . 4 ' be performed. The torque at the gearbox output results from the sum of the clutch torque of the first sub-gearbox 5 assigned clutch 4 with the translation of the first gear and the clutch torque of the second sub-transmission 5 ' assigned clutch 4 ' with the translation of the second gear. In this way, the required friction work on both clutches 4 . 4 ' be distributed.

During the acceleration phase of the vehicle, the differential speed in the first sub-transmission 5 assigned clutch 4 strive towards zero first. Shortly before this state is reached, this clutch 4 fully opened and the vehicle is only with the second sub-transmission 5 ' assigned clutch 4 ' accelerated further. At the same time, in the partial transmission 5 switched from first to third gear. When this shift is complete, the clutch begins 4 close again and thus supports the clutch 4 ' ,

If necessary, the procedure can be continued analogously for the shift into fourth gear; depending on the respective conditions, it may be appropriate to continue the procedure until the clutch is opened for the first time 4 perform.

The method according to the invention has the advantage that the couplings used 4 and 4 ' must be designed smaller with regard to the thermal load capacity. Nevertheless, the maximum engine torque should be able to be transmitted.

The method can also be applied analogously to multiple clutch transmissions. For example, in a three-clutch transmission with three clutches the friction work is distributed over the three clutches.

1

Double clutch

2

drive shaft

3

output shaft

4

clutch

4 '

clutch

5

first subtransmissions

5 '

second subtransmissions

Claims (6)

Method for starting for a multiple clutch transmission, in particular a double clutch transmission, with an input shaft, an output shaft, with at least two starting clutches and at least two partial transmissions, which generate different gears, each starting transmission being assigned a starting clutch, characterized in that for starting, at least two starting clutches ( 4 . 4 ' ) are used, with each of the at least two starting clutches ( 4 . 4 ' ) coupling sub-transmission ( 5 . 5 ' ) a gear is engaged so that the thermal load when starting off is at least two clutches ( 4 . 4 ' ) distributed, the torque at the gearbox output being the sum of the clutch torques of the at least two starting clutches ( 4 . 4 ' ) with each in the at least two sub-transmissions ( 5 . 5 ' ) generated gear ratios. A method according to claim 1, characterized in that before the differential speed in the first partial transmission ( 5 ) with the clutch currently assigned to the highest gear ratio ( 4 ) assumes the value zero that this sub-transmission ( 5 ) assigned coupling ( 4 ) is fully opened, whereby the vehicle with the second sub-transmission ( 5 ' ) assigned coupling ( 4 ' ) is accelerated further and at the same time in the first sub-transmission ( 5 ) to a height ren gear than the gear of the second sub-transmission ( 5 ' ) is switched over, and when this shifting process is completed, the first partial transmission ( 5 ) assigned coupling ( 4 ) is closed again to the clutch assigned to the second sub-transmission ( 4 ' ) to support. Method according to claim 1 or 2, characterized in that at the start of the starting process in the first partial transmission ( 5 ) the first gear and in the second sub-transmission ( 5 ' ) the second gear is engaged. Method according to one of the preceding claims, characterized in that in a double clutch transmission both starting clutches ( 4 . 4 ' ) are used, with each of the at least two starting clutches ( 4 . 4 ' ) coupling sub-transmission ( 5 . 5 ' ) a gear is engaged. Method according to one of the preceding claims, characterized in that that the sum of the drive torque is constant during the starting process remains. Method according to one of the preceding claims, characterized in that that the drive motor starts from its idling speed to a slightly increased Speed with the highest possible Torque is raised and at this speed the drive motor is held until the slipping process in the clutches is completed.