DE3735184A1 - Arrangement for controlling the gear change of a motor vehicle transmission - Google Patents

Abstract

A control for a semi-automatic transmission of a motor vehicle, in which the gear stages engaged are preselected by the driver, is equipped with a plausibility monitoring for the preselected gear stage; this prevents the acceptance of a gear stage which would lead to over-revving or stalling of the driving internal combustion engine. In certain driving conditions, it seems necessary, however, to suppress this plausibility monitoring. This is achieved in that a shift command transmitter is moved beyond the normal gear stage preselect position by increased operating force, so that the preselected gear stage is engaged, bypassing the plausibility monitoring.

Description

The invention relates to an arrangement according to the preamble of the main claim.

Motor vehicles are increasingly using so-called semi-automatic transmissions equipped, which the driver of the job of changing gears facilitate and possibly also remove the actuation of a clutch however, leave the opportunity to choose a suitable gear intervene. The same applies to vehicles with automatic transmissions, which the speed levels are limited (reduced) to a level desired by the driver can.

However, in order to safeguard against incorrect operation by the driver, it makes sense to the choice or preselection of the gear step of a so-called Subject to plausibility monitoring. This prevents one Gear stage is inserted at which the speed of an internal combustion engine Motor vehicle in an downshift an upper limit exceeds (over-revving the internal combustion engine) or at one Upshifting falls to a value below the idle speed is (stalling of the internal combustion engine).

However, this plausibility monitoring can be undesirable, for example when a heavily loaded motor vehicle is on a downhill gradient and another Vehicle brake supported by the braking effect of the internal combustion engine should or should be.

If the driver chooses a lower one because the engine braking effect is too low Gear stage at which the engine speed is above the plausibility limit increases, the transmission control does not assume this gear.

From EP-00 46 845A2 goes a semi-automatic transmission control a plausibility check, which indicates the insertion of unsuitable Gears, for example when skipping multiple gears prevented.  

For this purpose, a locking device is arranged on the shift lever, which only ever allows a plausible jump by one gear. This locking device can made ineffective by means of a switch arranged on the shift knob if a jump over several gear levels within the plausible Speed limits is possible.

It is an object of the invention to provide an arrangement for controlling the gear change to create a motor vehicle transmission, which the a driver Possibility to intervene in the selection of a suitable gear and suppress the plausibility check by simple measures, so that a gear deemed suitable by the driver can be engaged at any time can.

The object is achieved by the characterizing features of claim 1. Further features of the invention which are advantageously designed are shown in contain the subclaims.

The main advantages are that one Plausibility monitoring of a gear preselected by a driver simple measures are suppressed and those deemed suitable by the driver Gear can be engaged at any time. The measures are characterized constructive simplicity and are inexpensive with little effort producible. A special design also results in the Service case a clear traceability of such deliberately exceeding the plausibility limits.

The invention is illustrated and exemplified in drawings explained below.

It shows

Fig. 1 is a block diagram of an arrangement for controlling the gear shift of a motor vehicle transmission,

Fig. 2 is a switch commander according to the prior art,

Fig. 3 is a switch commander with an extended actuation to initiate a command signal modified according to the invention,

Fig. 4 shows a detail X of the shift commander of FIG. 3,

Fig. 5 is a flowchart of a control program of the array,

Fig. 6 is a flow chart of Fig. 5, but for an interrupt program.

In Fig. 1 is shown an arrangement for controlling the gear shift of a vehicle transmission 2 with 1. The transmission 2 is driven by an internal combustion engine 3 via a friction clutch 4 or a hydrodynamic torque converter. The control or implementation of the gear change (and possibly additionally the clutch 4 ) is carried out by means of a control unit 5 via servo elements 6 , a driver of the motor vehicle being able to preselect a gear stage via a shift command transmitter 7, 7 ' . Finally, a display 8 is also provided, which indicates an engaged and / or preselected gear stage. The control unit 5 is preferably constructed in microcomputer technology and processes input signals from the shift command transmitter 7, 7 ' (preselection signal kv) , from the transmission 2 (transmission measurement signals mg , for example gear stage k and transmission output speed na) , and u. U. of the clutch 4 (clutch measurement signals mk) and the internal combustion engine 3 (engine measurement signals mm) and determines command signals bs for the servo elements 6th The servo elements 6 performing a gear change are preferably of an electromotive, magnetic, hydraulic or pneumatic type and convert the command signals bs into gearbox control signals sg for the gearbox 2 or into clutch control signals sk for the clutch 4 .

In FIG. 2, a embodied as a rocker switch commander 7 is shown according to the prior art, which is disposed in a body of the motor vehicle in the handling area of the vehicle driver. Its shift lever 9 , which can be deflected from a rest position R1 at least in one plane, that is to say in two directions h, r about an axis of rotation 10 fixed to the vehicle and returns to this after actuation. For this purpose, two return springs 11, 12 act against the body and act against one another on the shift lever 9 . The deflection of the shift lever 9 is limited in both directions r, h by stops 13, 14 of a guideway 15 which is also fixed to the body. Both end positions of the shift lever 9 are (non-contact preferably) by limit switches 16, sampled 17, being selected by the first limit switch 16 is an upshift (upshift signal kvh) and by the second limit switch 17, a downshift (downshift signal kvr) or initiated.

The upshift signal kvh or the downshift signal kvr is subjected to a plausibility check in a known manner by the control unit 5 according to FIG. 1, in that the control unit calculates a transmission input speed nmot in the preselected gear stage from the transmission output speed na and the preselected gear stage kv and this with lower (upshift ) Limit values and with upper (downshift) limit values. If these limit values are undershot or exceeded, the preselected gear stage is ignored, not accepted or delayed until the limit values are reached.

In order - as described above - to be able to suppress the plausibility check at least for one downshift, the switching command generator 7 is modified according to the invention. An example of such a modified switching command transmitter 7 ' is shown in Fig. 3, which allows suppression of the plausibility check for downshifts.

For this purpose, the guideway 15 of the switching command transmitter according to FIG. 2 is first enlarged by a certain angular range (modified guideway 15 ' ), so that the switching lever can be actuated in an enlarged manner beyond the downshift position. This takes place against an increased restoring force of a variable stop 18 , which is supported by means of a prestressed spring 19 against an enlarged stop 14 'of the modified guideway 15' . The variable stop 18 forms a pressure point in the actuation of the shift lever 9 at the point at which the downshift r is triggered with a plausibility check, ie the shift lever 9 faces the second limit switch 17 .

By additionally applying the restoring force applied by the spring 19 , the shift lever 9 can be actuated until it faces a third limit switch 17 ' . This then outputs a modified downshift signal kvr ' , which triggers a downshift without taking into account the plausibility monitoring.

According to Fig. 4, which shows a detail X of FIG. 3, the variable stop 18 can also be secured by a tear-off pin 20 (predetermined breaking member), which can tear off by increased actuating force on the shift lever at a desired location between the stop 18 and the guideway 15 ' . In this way, in the event of service, it is possible to prove at any time that an implausible switching has been requested or willfully carried out.

It is also possible with electronic control devices 5 capable of diagnosis to provide such evidence by noting this extended actuation in a fault memory with the time and date; then the tear-off pin 20 can be omitted.

Of course, it is also possible to introduce a bypassing of the plausibility monitoring for upshifts; then only the switching command transmitter according to Fig. 3 or 4 is to be expanded in mirror image.

In FIGS. 5 and 6, finally, is a flow chart of a control program of the control unit 5 is illustrated, Fig. 5 illustrates a main routine and Fig. 6, an interrupt program which is triggered by one of the limit switches 16, 17 and 17 'and a flow of the Main program interrupts.

After switching on the control device 5 or the ignition current of the internal combustion engine 3 , the program start 21 and the initialization phase 22 begin, in which the computer is brought into a basic state and memories and flags are reset. After passing a mark A , measured values are recorded at the input of the control device 5 , 23 , and processed, 24 . It is queried whether a flag is set to 1, 25 ; if yes, it branches back to mark A , if not, it is queried whether the engine speed nmot is greater than an upper limit nmax , 26 . If so, after passing a mark B , a query is made as to whether the top gear kmax is engaged, 27 ; if no, the gear step k is increased by 1, 28 , and a subroutine "upshift", 29 is called, which carries out a gear change to a higher gear step, but which should not be dealt with in more detail, and branches back to mark A after its execution, if the query 27 is positive, the process continues to mark A.

If query 26 is negative, the method continues to query 30 which checks whether engine speed nmot is less than a lower limit value nmin ; if no, the system branches back to mark A , if yes, via a mark C to a query 31 which checks whether the lowest gear step kmin is engaged; if yes, the program branches back to mark A ; if no, the gear step is reduced by 1, 32 , and the subroutine "downshift", 33 is called to carry out the gear change, which is likewise not to be discussed. When it expires, the program branches back to mark A.

The interrupt program of FIG. 6 kv by one of the signals kvr, kvr 'of the limit switches 16, 17, 17' triggered and stored the gear preselection, 34. A query is made 35 whether kv is kvr ′ ; if so, the flag is set to 1, 36 , and the fault memory of the control unit 5 is written , 37 . The brand C is then returned to.

If no, a further query 38 checks whether kv is kvr ; if yes, the engine speed nmot is calculated in the next lowest gear nmot = nmot ((k -1), na)) , 39 and a further query 40 checks whether nmot is greater than nmax . If so, the branch is returned to mark A , if not, the flag is set to zero, 41 , and the process continues to mark C. If query 38 is negative, the flag is set to zero, 42 and the engine speed in the next higher gear nmot = nmot ((k +1) na)) is calculated, 43 . Finally, a query 44 determines whether the engine speed nmot is less than nmin ; if yes, branch to brand A , if no, branch B

The two subroutines 29 and 33 (upshift, downshift) depend on the type of transmission. Such sequence programs are known per se, so that there is no need to go into them in detail.

However, the invention is not only based on semi-automatic transmissions Rocker switch limited as a switching command transmitter, but in the same way also for other switching command transmitters (e.g. with the known H circuit) or  for limiting the gear stages of an automatic transmission to lower ones Gear steps applicable. The switching command transmitter is then closed in the same way modify.

The programs described in FIGS. 5 and 6 are constructed in such a way that, if the shift is not plausible, they process a selected gear stage preselection as not being given. It is of course conceivable to redesign this program so that the gear stage preselection remains stored until plausible speed limits are reached and the requested shift is then carried out.

Claims (10)

1. Arrangement for controlling the gear change of a motor vehicle equipped with a transmission, in which gear stages of a transmission are preselected, limited or triggered by a driver via a shift command transmitter and a gear change depending on shift signals of the shift command transmitter (preselection signals) and / or of operating and / / or driving parameters are carried out by means of servo elements controlled by a control unit, the switching signals (preselection signals) being subjected to a plausibility check which suppresses the switching signals (preselection signals) of the switching command transmitter, provided that the preselected gear stage after gear change has been carried out is too undesirable or inadmissible due to the speed being too high or too low Operating conditions or damage to the internal combustion engine and / or the transmission and / or a clutch, characterized in that the switching command transmitter ( 7, 7 ' ) to devices ( 14', 15 ', 17', 18, 19 ) is tert, can be used with which the plausibility check is suppressed, so that a gear change in a preselected or limited, undesirable or impermissible operating states (nmot <nmax, nmot <nmin) leading transition stage (k) is made possible. 2. Arrangement according to claim 1, characterized in that the switching command transmitter ( 7 ) is modified such that the plausibility check suppressing, gear stages (k) preselecting, triggering or limiting devices ( 14 ', 15', 17 ', 18, 19 ) can be controlled by extended actuation beyond a normal actuation change of the switching command transmitter ( 7 ). 3. Arrangement according to claim 2, characterized in that the extended Actuation overcoming an increased restoring force and / or mechanical, hydraulic or pneumatic escapement required.   4. Arrangement according to claim 2 or 3, characterized in that the extended actuation requires destruction of a predetermined breaking member lying in the extended actuation path (tear-off pin ( 20 )). 5. Arrangement according to claim 3 or 4, characterized in that the extended actuation is stored in a fault memory of the control unit ( 5 ) by date. 6. Arrangement according to at least one of the preceding claims, wherein the switching command transmitter is constructed in the form of a rocker switch, which can be rotated in at least one plane from a stable rest position to limited end positions and wherein the limitation takes place by a guideway with two stops, which Limit switches for triggering switching signals ( upshift signal kvh , downshift signal kvr) are assigned, characterized in that the guideway ( 15 ) is expanded (modified) at least in the direction of downshifting (r) ( 15 ′ ) and the extended actuation path can be overcome by an increased actuating force Inhibition is limited and a further, a modified downshift signal (kvr ') generating limit switch ( 17' ) is arranged in the extended actuation path . 7. Arrangement according to claim 5, characterized in that the escapement is formed by a variable stop ( 18 ) which is supported by means of a prestressed spring against a modified stop ( 14 ' ) of the modified guideway ( 15' ). 8. Arrangement according to claim 7, characterized in that the variable stop is connected via a tear-off pin ( 20 ) with the modified guideway ( 15 ' ). 9. Arrangement according to claim 8, characterized in that after triggering a modified downshift signal (kvr ') and the gear change caused thereby renewed gear change depending on operating and / or driving parameters or further downshift signals (kvr) are suppressed until plausible Speed values in the next lowest gear (nmot = nmot ((k -1), na) less than or equal to nmax) have been reached or until an upshift signal (kvh) has been triggered again. 10. The arrangement according to at least one of the preceding claims, characterized in that the suppression of a switching operation by the plausibility monitoring is carried out in such a way that either the switching signals (kvr, kvh)

• - used as not given, or
• - Delayed in the preselected gear ratio (k) until plausible speed values are reached (nmin less than or equal to nmot less than or equal to nmax) .