DE4017961A1 - Vehicle double clutch gear change control system - has synchronisation on all gears controlled from output shaft during gear change - Google Patents

Abstract

The transmission has a double clutch (A, B) on the input side of the gearbox, with the two clutches ooperating in overlap to change gear under full load. The synchromesh on each gear is operated from the output shaft (15) and operates on all gears during gearchange. This allows gearcahnge between any two ratios, without having to switch through the gear range. The synchromesh action is moved to higher speeds when the system is braking or accelerating, providing more control. An electronic processor controls the gearchanges using programmed values and linked ot the transmission by sensors. ADVANTAGE - Improved gearchange, cna change between any two gears.

Description

The invention relates to a control system for a powershift double clutch transmission with one electronic control unit in which characteristics, maps and control programs are stored and associated with Vehicle and engine sizes and the driver request via the Throttle switch and the position of the accelerator pedal electrical Output signals for switching and controlling controllable valves generated, the actuating cylinders for Adjustment of power shift clutches and Synchronous clutches of the gears in the transmission with one Pressurized medium, the speeds above Sensors and the position of the couplings via displacement sensors and feedback reported to the electronic control unit will.

Such a power shift double clutch transmission with a control system and an electronic control is described in VDI report No. 466/1983, pages 101 to 108. The drive in this transmission is divided into two coaxially arranged shafts, each shaft being connected to a clutch. The gears G 1 , G 3 , G 5 are assigned to one shaft, the gears G 2 , G 4 and GR to the other shaft or clutch. By actuating the corresponding clutch, it is possible to switch from one gear of one shaft to a gear of the other shaft without interrupting the tractive force. For this purpose, the coupling is pressurized hydraulically via an actuating device. The actuators are controlled by an electro-hydraulic control unit in which a specific control program is stored and which responds to signals from a gear selector lever. Figure 5 of this publication shows a gear sequence diagram with the order of the possible power shiftable gear sequences and Figure 6 shows the shift sequence of an upshift, for example. From the description in the latter picture and from this itself it can be seen that a gear change takes place in three phases.

• 1. Insert the new gear
• 2. Changing the clutch of the power shiftable clutches
• 3. Take out the old aisle

After that, a load circuit is only in the Gear order or in an order possible from The clutch works gear to gear even when there is a gear jump changes, e.g. from aisle 1 to aisle 4 according to picture 2. On Gear jump over only one gear, e.g. from gear 1 to gear 3, can not. In addition, the gear change is still too slow, especially if before changing the clutch too high a differential speed between the old and the new gear must be synchronized.

Based on the font above it is Object of the invention, a control system according to the Preamble of claim 1 in the direction of switching options to develop further. In particular, the circuits should faster and better for each driving situation be customizable.

This task comes with the distinctive features fulfilled by claim 1.

While in the prior art synchronizing the new gear only takes place when the power shift ends and the line in which the new gear lies is free of load, this synchronization takes place during the Overlapping circuit of the power shift clutches. This makes it possible to still during or immediately on End of the first load switching - namely when the  Synchronization of the new gear is complete - the next load switching if this is the Driving situation required. The first load circuit to the end, but also after synchronization of the following course are canceled. A power shift from 1st gear to 3rd gear with no dwell time in 2nd gear possible because the synchronization of the new gear during the slip phase of the power shift clutches he follows. The shift from gear 1 to gear 2 to gear 3 is like a direct powershift from gear 1 felt after course 3.

This has the disadvantage that load switching Double clutch transmissions only from gear to gear or with a gait jump over two gears are possible, in which in any case the couplings are changed - see picture 5 of the above-mentioned font -, overcome.

The invention is advantageously designed when strong braking and accelerating the beginning of the Synchronization towards higher differential speeds be moved there. Because the higher delay or Acceleration of the output shaft synchronizing favors the permissible Load parameters not exceeded. While after State of the art in determining the maximum possible Differential speed was assumed that during the Synchronizing the vehicle speed and so that the speed of the output shaft remains constant according to the invention resulting from the driving situation Change in speed when determining the maximum Speed difference also taken into account. The Synchronization process can therefore at a higher Differential speed begin, so that the synchronization is completed before the vehicle speed to the corresponds to new gear to be shifted. Will be the one to be replaced  Coupling with the power shift only shortly before the start of Synchronization of the new gear shift clutch completely opened, this is partially synchronized Drive train through the clutch. The speed of the The drive shaft can not run away, so that too synchronizing speed differences through the participation the gear shift clutches are lower. The This makes synchronization faster and with one lower load on the synchronization devices. In order to it is possible to sync even smaller ones to use. A is particularly advantageous Double clutch transmission when the powershift Couplings directly in the input area of the gearbox with the Drive shaft are connected and if the Synchronizing clutches for the gears as double clutches are arranged on the output shaft. For one Transmission results in a particularly favorable one Control device in a special configuration acts electro-pneumatically.

Also from ATZ "Automobil-Technische Zeitschrift" 1989 (1987) 9, pages 439 to 452, is a power shiftable Double clutch gearbox known, in principle similar which is already described. From this too Description is a power shift in gear order or possible in an order that goes from course to course the clutch also changes when there is a gear shift, e.g. Gear 1 to gear 4 according to picture 2. A gear jump over only one Aisle, e.g. from gear 1 to gear 3, cannot take place.

The invention is not based on the combinations of features of claims limited. For the person skilled in the art further sensible combinations of requirements and individual claim characteristics from the task.

Further details of the invention are based on Drawings and exemplary embodiments explained. Show it:

Figure 1 is a schematic diagram of a 5-speed double clutch transmission.

Figure 2 shows an electro-pneumatic control for gear shifting in a schematic representation.

Fig. 3 shows a switching sequence;

Fig. 4 shows a drive train in 1st gear

Fig. 5 shows a drive train in 2nd gear

Fig. 6 shows the representation of a drive train in 3rd gear

The double-clutch transmission 1 according to Fig. 1 consists of a drive shaft 11 for the two power shift clutches A, B. By the clutch plate A 1 of clutch A is the central input shaft 12 to the gear 121 and the clutch plate B 1 of the coupling B the hollow shaft 13 to gear 131 . With the countershaft 14 , the gears are firmly connected in the order from left to right 141 to 145 , and the double gear 16 is loosely arranged on the countershaft 14 between the gears 141 and 142 . The transmission output shaft 15 is mounted in the central input shaft and carries the clutch bodies 151 to 153 for the synchronous clutches of the gears G 1 to G 5 and GR, the gear wheels 17 loosely mounted on the output shaft 15 being the 2nd gear, 18 the 3rd Gear, 19 are assigned to 1st gear, 20 to R gear and 21 to 5th gear. In the wheel train 20/144 from the R gear, an R gear wheel 22 is also arranged to reverse the direction of rotation. The drive train in connection with the clutch A in this example are the central shaft 12 with the gear 121 , the double gear 16 loosely arranged on the countershaft and the idler gear 17 on the output shaft 15 and the clutch body 151 on the output shaft 15 and the synchronous clutch of the Gears G 4 and G 2 assigned. From the clutch B, the other drive train leads via the hollow shaft 13 and the gears 131/141 to the countershaft 14 and then optionally

• - Via the gears 142/18 and the synchronous clutch of the third gear G 3 and the synchronizer body 152 to the output shaft 15 ;
• - Via the gears 143/19 and the synchronizer clutch of the 1st gear G 1 and the synchronizer body 152 to the output shaft 15 ;
• - Via the gears 144/22/20 and the synchronous clutch of the R-gear and the synchronizer body 153 to the output shaft 15 ;
• - Via the gears 145/21 and the synchronizer clutch of the 5th gear G 5 and the synchronizer body 153 to the output shaft 15 .

As a result of this construction, it is possible, in a known manner, to shift five gears with only two power shift clutches A, B without load interruption and gear shift restrictions which have been customary to date. In the control system for a double clutch transmission 1 according to FIG. 2, the shafts and clutches are designated as already described in FIG. 1. 11 is the drive shaft for power shift clutches A and B, the central input shaft 12 leading from clutch A into the transmission to the synchronizing clutches of gears G 2 and G 4 . The hollow shaft 13 leads from the power shift clutch B and the spur gear chain 131/141 to the countershaft 14 and from there in the manner already described in FIG. 1 to the synchronous clutches of the gears G 1 , G 3 , G 5 and GR. 15 is the transmission output shaft. The electronic control unit 3 receives the load requirements and the wishes of the driver via the signal from the position of the accelerator pedal 31 and the driving switch 32 . The speed of the drive shaft 11 equal to N _mot or N _on , the input shafts 12 , 13 equal to N _A , N _B and the transmission output shaft 15 equal to N _ab are detected by sensors 33 and corresponding signals are fed to the electronic control unit 3 via line 34 . To operate the power shiftable clutches A, B, single-acting actuating cylinders are arranged, the filling of which is controlled by solenoid valves 5 A, 5 B, these receiving their switching impulses from the electronic control unit. The respective position of the actuating cylinders 4 A, 4 B and thus of the clutches A and B is detected via displacement sensors 41 A, 41 B and passed via lines 42 to the electronic control unit 3 as displacement signals. The three double clutches of the gears G 2 / G 4 ; G 1 / G 3 and G 5 / GR are each shifted from a three-position cylinder 6 into the respective gear position or into the middle position - neutral position. For this purpose, two solenoid valves 5 are arranged for each three-position cylinder 6 , which are acted upon by the electronic control unit 3 . The three positions of the three-position actuating cylinders are also assigned feedback 61 which transmit the respective position to the electronic control unit via line 62 . The three-position cylinder 6 and actuating cylinder 4 A, 4 B are acted upon by the solenoid valves 5 "G 1 " to 5 "G 5 " and 5 A, 5 B via compressed air, for which purpose all solenoid valves with a compressed air source 51 via line 52 and are connected to the three-position cylinders and actuating cylinders 4 A, 4 B via the lines 53 .

Fig. 3 shows an upshift of gear G 1 in the gear G 3, plotted over time t, being shown only the overlap shift from the gear G 1 on the gear G 2 in detail, and to it immediately the load circuit of gear G 2 to gear G 3 is connected. The upper diagram 7 shows the shift sequence and below that the diagram 8 shows the speed curve at the transmission input. In the third diagram the clutch moments 9 and in the last diagram the positions of the synchronizations over the elapsed time t of this upshift are plotted. The vehicle runs in 1st gear, see also FIG. 4, in that the drive train via the drive shaft 11, the power shift clutch B, the hollow shaft 13 , the gear wheels 131/141 , the countershaft 14 , the gear wheels 143 and 19 to the output shaft 15 via the synchronizing clutch 1st gear G 1 is closed. Gear G 2 is synchronized in the drive train of clutch A and gear G 1 is synchronized in the drive train of clutch B. Clutch B is closed when the vehicle is running in 1st gear. The clutch A has the speed N _from × i ₂ and is load-free. When the gear shift point for an upshift is reached, which is determined and recognized in the electronic control unit, the load shift follows from gear G 1 to gear G 2 , see line 71 in FIG. 3. With only a slight time delay, the solenoid valve 5 becomes "A" of the clutch A applied - line 72 -. Line 73 shows the feedback from the displacement sensor 41 , which characterizes the closing process in clutch A. Simultaneously with the closing of clutch A, clutch B is opened to a residual torque, see line 74/75 . For this purpose, the solenoid valve 5 B is acted upon accordingly, and the displacement sensor 41 B reports the corresponding position of the clutch to the electronic control unit 3 . Now the synchronizing clutch of the 1st gear is brought into the neutral position by actuating the solenoid valves 5 "G 1 " and 5 "G 3 " - the corresponding three-position cylinder 6 and the double clutch of the gears G 1 / G 3 are adjusted to the middle position - . Completion is confirmed via the corresponding feedback 61 to the electronic control unit - line 77 -. The speed of the almost load-free clutch B does not increase with the speed of the output shaft, but falls with the engine speed during the power shift. The size of the existing differential speed, which is a decisive factor in the load on the synchronization, can thus be significantly reduced, and thus a smaller synchronization can be used. The speed of clutch B thus moves toward the output speed N _ab , the differential speed N _an - N _ab × i ₃ constantly decreasing and thus falling below the maximum permissible differential speed at the synchronization of gear G 3 at an early stage. If the maximum permissible differential speed for the synchronization of 3rd gear G 3 is undershot, actuation of solenoid valve 5 B opens clutch B completely, see also line 75 . Now the new gear G 3 is synchronized - line 78 -. For this purpose, the solenoid valve 5 "G 3 " is acted upon, and the corresponding three-position cylinder 6 moves the clutch for the 3rd gear G 3 for synchronization in the direction of the gear wheel 18 . After synchronization of the 3rd gear has been completed - this is indicated by the feedback 61 from gear 3 according to FIG. 2 - it is possible to connect the second power shift up to the 3rd gear G 3 immediately - line 79 , FIG. 3 -. The synchronization that has taken place is determined via the speed sensors 33 and ascertained in the electronic control unit 3 . The speed curve 8 at the transmission input according to FIG. 3 results from the shift sequence described in FIG. 7 as follows:

In accordance with, for example, the load demand via the accelerator pedal 31, the engine speed N _mot = N rises _and reaches the switching point 81 at the gear G 1 to G transition. 2 After load acceptance of clutch A, the speed of the almost load-free clutch B does not increase with N _ab × i ₁ , but falls during load switching with the engine speed or the speed of the drive shaft N _mot , N _an . The considerable speed drop during the synchronization of the third gear can also be seen very well from the speed curve at the transmission input 8 , so that with the completion of this synchronization at point 82 or as shown at the end of the load shift from G 1 to G 2, the load shift from G 2 to G 3 can begin. The time in which the drive train of clutch B is partially synchronized is shown at 91 in the diagram of clutch moments 9 . This synchronization is triggered via the still existing partial torque of clutch B - designated 92 - this partial synchronization creating the prerequisites for the synchronization of the gear shift clutch G 3 during the power shift from gear 1 to gear 2. The establishment of the synchronization according to FIG. 10 , FIG. 3, in our opinion requires no further explanation, since it has already been described in connection with the switching sequence 7 . While, as described in 1st gear, the drive train of FIG. 4 in a double-clutch transmission of the clutch B on the 1st gear G is effective 1, at the end of the load circuit G 1 to G 2, the drive train of Fig. 5 effective . The power flow goes from the transmission input shaft 11 via the power shift clutch A to the central input shaft 12 and to the gear 121 . The loose gear 17 is then driven on the output shaft 15 via the loose double gear 16 rotating on the countershaft 14 and the output shaft 15 itself is driven via the synchronous clutch of the second gear G 2 . Since the power shifts from gear 2 to gear 3 immediately follow the power shift 1 to 2 described in detail, there is no dwell time in the 2nd gear, so that after the power shift from gear 2 to gear 3 has been completed, which in principle is the same as the power shift described 1 to 2 runs, the drive again via the clutch B goes with the drive train according to FIG. 6. The drive takes place via the drive shaft 11 and the clutch B, the hollow shaft 13 , the gear wheels 131/141 , the countershaft 14 , the gear wheels 142 and 18 to the output shaft 15 via the synchronizing clutch of the 3rd gear.

Reference numerals

A Powershift clutch
A 1 clutch disc
B Powershift clutch
B 1 clutch disc
1 double clutch transmission
11 drive shaft
12 central input shaft
121 gear
13 hollow shaft
131 gear
14 countershaft
141-145 gears
15 gearbox output shaft
151-153 clutch body
16 double gear loose
17-21 gears loose on the output shaft
22 reverse gear
G 1 - G 5 synchronous clutches of the gears
GR reverse gear
G 4 / G 2 double clutch
G 3 / G 1 double clutch
GR / G 5 double clutch
3 electronic control unit
31 accelerator pedal
32 travel switches
33 speed sensors
34 lines
4 A , 4 B actuating cylinders
41 displacement sensor
42 line
5 A , 5 B solenoid valves
5 "G 1 " - 5 "G 5 " solenoid valves
5 "GR" solenoid valve
51 pressure medium source
52 line
53 line
6 three-position cylinders
61 feedback
62 management
7 Diagram switching sequence
71-79 line
8 Speed curve diagram
81 switching point G 1 - G 2
82 End of synchronization G 3
9 Diagram of the clutch torques
91 Synchronization of the drive train of clutch B
92 partial torque of clutch B
10 Position of the synchronization
t time
N _an = N _mot engine speed, speed of the drive shaft
N _{from the} speed of the output shaft
N _A Speed of clutch A
N _B speed of clutch B

Claims (6)

1.Control system for a double clutch transmission ( 1 ) with an electronic control unit ( 3 ), in which the characteristic curves, maps and control program are stored and in connection with the vehicle and engine sizes and the driver's wishes via the travel switch ( 32 ) and the position of the accelerator pedal ( 31 ) electrical output signals for switching and controlling controllable valves ( 5 ) are generated, the actuating cylinders ( 4 , 6 ) for adjusting power shift clutches (A, B) and synchronous clutches of the gears (G 1 to G 5 , GR) in the transmission ( 1 be) subjected to a pressure means, detects the speed by means of sensors (33) and the position of the clutches via displacement sensors (41) and feedback module (61) and reported to the electronic control unit (3), characterized in that during a load circuit / overlap circuit of the Clutches (A, B) the gear shift clutches (G 1- G 5 ) are synchronized so that a shift over two gears ( G 1 , G 3 ) is possible without dwell time in the adjacent aisle (G 2 ). 2. Control system according to claim 1, characterized in that the start of synchronization for downshifting or upshifting is shifted to higher differential speeds in the case of strong braking and acceleration processes in the drive train, since the deceleration or acceleration of the output shaft ( 15 ) favors the synchronization . 3. Control system according to claim 1, characterized in that the clutch (A, B) to be released in an overlap shift transmits a residual torque until the start of synchronization in the gear shift clutch for the next gear (G 3 ) and thus that of the respective clutch (A , B) assigned drive train is partially synchronized. 4. Control system according to claim 1, characterized in that the powershiftable clutches (A, B) are connected directly to the drive shaft ( 11 ) at the input of the double clutch transmission ( 1 ), so that the drive trains which the clutches (A , B) are assigned, result in two coaxial input shafts (central input shaft 12 , hollow shaft 13 ) and that all synchronizing clutches for the gears (G 1 to G 5 , GR) are arranged on the output shaft ( 15 ). 5. Control system according to claim 1, characterized in that for controlling the power shift clutches (A, B) and the synchronizing clutches of the gears (G 1 to G 5 , GR)

• - An electronic control unit ( 3 ) is arranged, in which characteristics, maps and switching programs are stored and in which the driver's wishes are forwarded to the electronic control unit via the accelerator pedal ( 31 ) and the driving switch ( 32 ),
• - The speeds of the input ( 11 ) and output shaft ( 15 ) and the speeds from the respective drive train of the clutches (A, B) via sensors ( 33 ) and the position of the clutches (A, B) via displacement sensors ( 41 A, 41 B) and the position of the synchronizing clutches of the gears (G 1 to G 5 , GR) are reported to the electronic control unit ( 3 ) via feedback ( 61 ),
• - The powershift clutches (A, B) can be opened via an actuating cylinder ( 4 A, 4 B), and that the double clutches of the gears (G 4 / G 2 ; G 3 / G 2 ; GR / G 5 ) over Three-position cylinders ( 6 ) are adjusted to the neutral position or the gear positions of the gears (G 4 / G 2 ),
• - That one for the actuating cylinders ( 4 A, 4 B) and two for the three-position cylinders two solenoid valves ( 5 , 5 A, 5 B) are arranged, which are controlled by the electronic control unit ( 3 ) and the actuating cylinders via a pressure medium ( 4 , 6 ).

6. Control system according to claim 5, characterized in that the pressure medium is compressed air, and that the solenoid valves ( 5 ) are connected to a compressed air source ( 51 ).