DE4111645A1 - Controlling automatic transmission of motor vehicle - correcting gearchange positions when wheel-spin control operates - Google Patents

Abstract

Automatic transmission is provided with programmed gear-change positions w.r.t. engine speed and torque. During wheel-spin control, the gear-change positions are modulated to take account of the overall reduced throttle settings. The last non-adjusted throttle setting is taken as a reference. The system allows gear-change under programmed conditions, e.g. hill work, during wheel-spin control. The gear-change operations are stabilised to prevent undue switching during wheel-spin control. ADVANTAGE - Improved stability, quiter operation.

Description

The invention relates to a method according to the preamble of Claim 1.

Such a method is known from DE 39 27 349 A1, in which during a control intervention of the traction control system in one force vehicle the gearbox control unit change gear within a time window and / or through the transition to specifically for the control intervention of the drive Slip control system suppressed shifting characteristic curves to pen prevent del circuits. - The following is under the term "Control intervention" always refers to the control intervention of the traction control system understand. - To carry out this Ver known from DE 39 27 349 A1 driving the internal combustion engine of the motor vehicle has two throttle valves on: a first throttle valve, its opening angle through the accelerator pedal given and used for the control of the gear change, and a second throttle valve, the opening angle of which by the drive slip Control system is set.

In such a device for performing the from DE 39 27 349 A1 known method, is given by the accelerator pedal at the same Throttle valve opening angle with a control intervention of the drive Slip control system a different vehicle speed than without Rule intervention. This can lead to a gear change contrary to the driver's request and lead to pendulum shifts when to control the gear change a control intervention, the switching characteristics used for the Nor painting operation, d. H. without rule intervention.

In the method known from DE 39 27 349 A1, shuttle circuits are intended can be avoided by special for operation during control intervention coordinated shifting characteristics can be used or gear changes within of a time window can be suppressed.  

The use of special switching characteristics is complex and memory intensive, since several maps depend on different conditions must be created and saved.

Suppression of switching operations during a control intervention within a time window is inflexible to different vehicles reactions such as B. the engine torque change or the vehicle speed gradient, under different driving conditions, such as. B. Ascent uphill or downhill ride.

It is an object of the invention in motor vehicles with an automatic transmission with control intervention of the traction control system flexible, simple and prevent space-saving oscillating circuits.

This object is achieved by the features of patent claim 1.

The switching points corresponding to the switching characteristics depend on the one hand the throttle valve opening angle specified by the accelerator pedal, on the other hand on the vehicle speed. It hangs without rule intervention Change in vehicle speed only from the opening angle of the first throttle valve, which is predetermined by the accelerator pedal. The public The opening angle of the second throttle valve is constantly 100% open. For In this case, the switching characteristics are matched. During a rule intervention this relationship between the position of the first throttle valve and the vehicle speed falsified, because then the by the Control intervention changed the opening angle of the second throttle valve the change the vehicle speed with determined. The transmission control unit receives information about start and from the traction control system End of rule intervention. This allows the gearbox control unit to change React behavior of vehicle speed. Basis of The method according to the invention remains the switching characteristics for the Normal operation, depending on which during a control intervention of relative vehicle speed changes related to the Vehicle speed is not mandatory at the beginning of the control intervention  Gear change is carried out. In addition, absolute top and defines lower upshift and downshift limits that change gear depending on other requirements for the vehicle such as maintaining the tractive force or advance or delay moment jump prevention. Because too low tractive effort or excessive torque jumps result in more dynamic Cooperation of the gearbox control unit with a drive slip Control system pendulum circuits.

With this method according to the invention for controlling the gear change in the event of a control intervention of the drive slip control system, simple Pendulum circuits wisely and without general suppression of gear changes prevented. Further development effort and storage space saved for the creation and storage of special maps.

A positive embodiment of the invention is the subject of Claim 2.

Downshifts during a control intervention are permitted within a defined vehicle speed range in accordance with the switching characteristic curves valid in normal operation. This vehicle speed range is between the lower downshift limit v _R1 and the upper downshift limit v _R2 . Below the lower downshift limit v _R1 , a downshift is carried out immediately, regardless of the switching characteristic. Above the upper downshift limit v _R2 , no downshift is carried out regardless of the switching characteristic. The lower downshift limit v _R1 and the upper downshift limit v _R2 can be defined specifically for each gear.

The lower switch-back limit v _R1 is used to maintain traction during a control intervention. The upper downshift limit v _R2 prevents excessive torque jumps, which would promote a drive slip and thus pendulum shifts on slippery roads.

Another positive embodiment of the invention is the subject of Claim 3.  

Is during a rule intervention, e.g. B. according to a shift characteristic, an upshift request before, the upshift is delayed as long as the vehicle speed has not reached a minimum value, the lower upshift limit v _H1 . The lower upshift limit v _H1 can be defined specifically for each gear.

Like the lower downshift limit v _R1, the lower upshift limit v _H1 serves to maintain tensile force during a control intervention. B. when driving uphill, the engine works in an optimal speed range for torque delivery, in which the traction control system can optimally control. In addition, this also avoids oscillating circuits.

Another positive embodiment of the invention is the subject of Claim 4.

If there is no upshift request above a certain maximum value of the vehicle speed, the upper upshift limit v _H3 , an upshift is carried out immediately, regardless of the shifting characteristic curves. The upper upshift limit v _H3 can also be defined specifically for each gear.

The upper upshift limit v _H3 , like the upper downshift limit v _R2 , prevents excessive torque jumps.

The lower upshift limit v _H1 and the upper upshift limit v _H3 have higher priority than the following configurations.

Another positive embodiment of the invention is the subject of Claim 5.

If there is an upshift request corresponding to a shift characteristic during a control intervention, the upshift is only carried out if the vehicle speed has increased by an amount δv since the vehicle speed value v _R that was present during the control intervention. Otherwise, the upshift is delayed until the vehicle speed has increased by δv.

This function is used to wait for changes in vehicle behavior through the control intervention and so long receives the better traction of the lower one Ganges until an acceleration of the vehicle despite reduced Drive torque is ensured. This function also works as a pendulum circuits against, otherwise with too little traction after a Upshifting the control intervention is terminated, causing the gearbox to return switches back.

Another positive embodiment of the invention is the subject of Claim 6.

If there is no upshift request during the control intervention after the vehicle speed has increased by the amount δv since the vehicle speed value v _R at the beginning of the control intervention, an upshift is carried out at the shift point in accordance with the shift characteristic.

The control of the gear change according to this embodiment also provides sure that the traction of the vehicle after an upshift during of a rule intervention is sufficient, otherwise not after the rule intervention trigger a downshift again.

Another positive embodiment of the invention is the subject of Claim 7.

Furthermore, an upper upshift threshold v _{H2 is} provided for the vehicle speed, which limits the embodiment of the invention in claim 8 to the effect that upshifting occurs immediately when the vehicle speed reaches this upper upshift threshold v _H2 . The upper upshift threshold v _H2 can also be defined on a gear-specific basis.

This additional function in turn prevents a gear change an excessive jump in torque at higher vehicle speeds causes a drive slip on smooth roads and thus Pendulum circuits would favor.

Another positive embodiment of the invention is the subject of Claim 8.  

If there is no upshift request during the control intervention, after the vehicle speed has increased from the vehicle speed value v _R at the beginning of the control intervention by the amount δv and at the same time the vehicle speed value (vR + δv) is above the upper upshift threshold v _H2 , one immediately becomes independent of the shift characteristics Upshift carried out.

This function also prevents a gear change at higher Vehicle speeds causes an excessive jump in torque.

Another positive embodiment of the invention is the subject of Claim 9.

The amount δv by which the vehicle speed v _R must increase before an upshift is carried out is defined differently for each gear. The smaller the gear, the greater the amount δv.

This function takes into account the different gear ratios of the individual Gears. The vehicle accelerates with the same throttle valve positions faster in a low gear than in a high gear. thats why even in low gears when changing the throttle valve opening angle a faster vehicle speed change possible. Thereby the pendulum shifts in low gears more from the vehicle speed dependent than in high gears. Thus, in low gears a stronger increase in vehicle speed awaited than in high gears.

An advantageous development of the invention is the subject of Claim 10.

If the road is icy over a longer section of road, the traction control system can be repeatedly activated at short intervals. The status of the previous control intervention is therefore retained in the transmission control unit for a time t _x . The time t _x is chosen empirically so that a new control intervention can be ruled out within a very short time.

This prevents frequent switching to different modes of the Transmission control unit causing unpleasant or faulty transmission reactions being able to lead.

Another advantageous embodiment of the invention is the subject of Claim 11.

If, during the time t _x, the driver takes his foot off the accelerator pedal, ie the position of the accelerator pedal triggers overrun operation, a renewed control intervention of the traction control system is unlikely, so that the maintenance of the status for a control intervention is unnecessary. Thus, the transmission control unit leaves this status even during the time t _x , when a threshold value for the throttle valve opening angle predetermined by the accelerator pedal is undershot to identify the coasting operation.

Possible exemplary embodiments of the invention are explained below. It shows

Fig. 1 is a downshift characteristic curve with the present invention downshift examples, wherein the predetermined accelerator pedal by the throttle valve opening angle during the control intervention is to remain constant,

Fig. 2 is an upshift characteristic curve with the present invention upshift examples, wherein the predetermined accelerator pedal by the throttle valve opening angle should remain constant during the control procedure.

The abbreviations used in the following description and in the figures have the following meaning:  

RA the beginning of the rule intervention,
RE the end of the rule intervention,
v the vehicle speed,
HS an upshift,
RS a downshift,
DKG the throttle valve opening angle, which results from the position of the accelerator pedal,
v _R the vehicle speed at the start of the control intervention,
δv is the constant vehicle speed amount by which the vehicle speed v _R must be increased in order to carry out an upshift,
v _H1 the lower upshift limit,
v _H2 the upper upshift threshold,
v _H3 the upper upshift limit,
v _R1 the lower downshift limit and
v _R2 the upper switchback limit.

In Fig. 1 and Fig. 2 is each an upshift characteristic line map of a switch, ie, shown from the plurality of shift characteristics. An upshift requirement corresponding to the shift characteristic generally results from increasing vehicle speed (v) and / or from an increase in the throttle valve opening angle (DKG). In both figures, the throttle valve opening angle (DKG) is plotted on the ordinate and the driving speed (v) is plotted on the abscissa. If the vehicle speed v _RS or v _{HS is} reached at which the throttle valve opening angle DKG intersects the upshift characteristic curve, there is a downshift request or an upshift request. This intersection of the vehicle speed v _RS or v _HS with the throttle valve opening angle DKG on the shift characteristic is also referred to as the shift point.

In Fig. 1 is a downshift characteristic curve is shown of a shift map. A downshift request corresponding to the downshift characteristic curve results from falling vehicle speed (v) and / or from a reduction in the throttle valve opening angle (DKG). The lower downshift limit v _R1 and the upper downshift limit v _{R2 are} entered on the abscissa.

In Fig. 1 three examples of a downshift during the control intervention are shown, wherein the throttle valve opening angle DKG predetermined by the accelerator pedal should remain constant.

In case 1, the vehicle speed v _R at the start of the control intervention is lower than the lower downshift limit v _R1 . In this case, according to the invention, a downshift is triggered immediately at the start of the control intervention, regardless of the downshift characteristic.

In case 2, the vehicle speed v _R at the beginning of the control intervention lies between the lower downshift limit v _R1 and the upper downshift limit v _R2 . If the vehicle speed drops to the value that results from the intersection of the throttle valve opening angle DKG₂ with the downshift characteristic, the system switches back.

In case 3, the control intervention begins at a vehicle speed v _R which is greater than the upper downshift limit v _R2 . Furthermore, the intersection of the throttle valve opening angle DKG₃ with the downshift characteristic at a vehicle speed which is also greater than the upper downshift limit v _R2 . In this case, downshifting is prohibited until the vehicle _{speed has} dropped to the value of the upper downshift limit v _R2 .

In FIG. 2, an upshift characteristic is shown in a shift map. An upshift requirement corresponding to the shift characteristic results from increasing vehicle speed (v) and / or from increasing the throttle valve opening angle (DKG). The lower upshift limit v _H1 , the upper upshift threshold v _H2 and the upper upshift limit v _{H3 are} entered on the abscissa. In FIG. 2, seven examples of an upshift are shown according to the invention during a control action, wherein the predetermined accelerator pedal by the throttle valve opening angle DKG is to remain constant.

In case 1, the vehicle speed v _R is more than the amount δv below the lower upshift threshold v _H1 . The intersection of the throttle valve opening angle DKG₁ with the upshift characteristic is at a vehicle speed which is also less than the lower upshift limit v _H1 .

This means that after the vehicle speed v _{R has} increased by the amount δv, an upshift request corresponding to the upshift characteristic is pending. With the definition of a lower upshift limit v _H1 , however, an upshift is only carried out according to the invention when the vehicle speed has reached the value of the lower upshift limit v _H1 .

In case 2, the control intervention begins at a vehicle speed v _R just below the vehicle speed lying at the intersection of the throttle valve opening angle DKG₂ with the upshift characteristic. Before this vehicle speed is increased by the complete amount δv, an upshift is requested in accordance with the upshift characteristic or in accordance with the lower upshift limit v _H1 . However, the upshift takes place according to the invention only after the vehicle speed has increased by the amount δv.

In case 3, the vehicle speed v _{R is} just below the lower upshift limit v _H1 . While the vehicle speed v _{R is} increased by the amount δv, the lower upshift limit v _{H1 is} exceeded, but the intersection of the throttle valve opening angle DKG₃ with the upshift characteristic is not yet reached. In this case, there is no upshift after increasing the vehicle speed v _R by the amount δv, since there is still no upshift request. Only after reaching the vehicle speed at the intersection of the throttle valve opening angle DKG₃ with the upshift characteristic is upshifted.

In case 4, the control intervention begins at a vehicle speed above the lower upshift limit v _H1 and just below the intersection of the throttle valve opening angle DKG₄ with the upshift characteristic. In this case, the upshift is requested before the vehicle speed is increased by the amount δv, but according to the invention is carried out only after the increase by the complete amount δv.

In case 5, after the vehicle speed v _{R has} increased by the amount δv, there is still no upshift pending according to the upshift characteristic. It is therefore only upshifted when the vehicle speed has reached the value which is assigned to the intersection of the throttle valve opening angle DKG₅ with the upshift characteristic.

In case 6, on the one hand, after increasing the vehicle speed v _R by the amount δv, there is still no upshift according to the upshift characteristic curve, on the other hand the vehicle speed has exceeded the value of the upper upshift threshold v _H2 . Exceeding this upper upshift threshold v _H2 is equivalent to an upshift request according to the invention. Therefore, after increasing the vehicle speed v _R , the gear is shifted up by the amount δv, even if the vehicle speed which is assigned to the intersection of the throttle valve opening angle DKG₆ with the upshift characteristic has not yet been reached.

In case 7, the control intervention begins at a vehicle speed shortly before the upper upshift limit v _H3 . While the vehicle speed v _{R is} increased by the amount δv, the value of the upper upshift limit v _{H3 is} exceeded. This is the only case in which neither an upshift request corresponding to the upshift characteristic curve nor the increase in the vehicle speed v _R by the full amount δv is waited for. When the upper upshift limit v _H3 is reached, the upshift takes place immediately.

In addition, other cases are due to the combination of cases 1 to 7 possible, which are not described here.

With the described embodiments, in a flexible manner, simple and saves space in the event of a control intervention of the drive slip Control system in connection with an electronic grate control unit Pendulum circuits prevented. In addition, sufficient traction is at get low vehicle speed or a too high moment jump avoided at high speeds.

Claims (11)

1. A method for controlling the gear change of a motor vehicle automatic transmission with electronic transmission control unit, which receives the vehicle speed and a throttle opening angle predetermined by the accelerator pedal as input signals and is correspondingly stored in the transmission control unit, the vehicle speed and this throttle opening angle-dependent shifting characteristic curves controls the gear change, the internal combustion engine of the motor vehicle with at least one throttle valve, the opening angle of which can be predetermined by the accelerator pedal, and is provided with a traction-slip control system that communicates its control intervention to the gearbox control unit and, through its control intervention on the first or a further throttle valve, the torque when the drive wheels slip the internal combustion engine reduced, characterized in that the gear changes during a control intervention of the traction control system depending on the vehicle speed are deviating from the shifting characteristic curves stored in the transmission control unit. 2. The method according to claim 1, characterized in that during the control intervention of the traction control system downshifts according to the switching characteristics only between a lower downshift limit v _R1 and an upper downshift limit v _{R2 are} permitted that none for a vehicle speed v <v _R2 Downshifts are allowed and that downshifts are carried out immediately for a vehicle speed v <v _R1 . 3. The method according to claim 1 or 2, characterized in that upshifts during the control intervention of the traction control system regardless of the switching characteristics for a vehicle speed v below a (for each gear) lower upshift limit v _{H1 are} not permitted. 4. The method according to any one of claims 1 to 3, characterized in that upshifts during the control intervention of the traction-slip control system regardless of the shifting characteristics for a vehicle speed v above an (for each gear) upper upshift limit v _H3 are carried out immediately. 5. The method according to any one of the claims 1 to 4, characterized in that upshifts during the control intervention of the traction control system at the earliest after increasing the vehicle speed v _R present at the beginning of the control intervention of the traction control system by a defined (gear-specific) Amount δv can be executed. 6. The method according to claim 5, characterized in that in the absence of an upshift request after the increase at the beginning of the control intervention of the traction control system driving speed v _R by a defined (gear-specific) amount δv an upshifting at the vehicle speed v _K at the latest which results from the intersection of the throttle valve opening angle specified by the transmission control unit for the gear change with the next upshift characteristic. 7. The method according to claim 5 or 6, characterized in that in the absence of an upshift request after the increase at the start of the control intervention of the traction control system driving speed v _R by a defined (gear-specific) amount δv an upshift at the latest at the upper upshift threshold v _{H2 is} executed when the vehicle speed v _K , which results from the intersection of the throttle valve opening angle selected by the transmission control unit for the gear change with the next upshift characteristic, is greater than the upper upshift threshold v _H2 and the vehicle speed v _R + δv is less than that upper shift threshold v _H2 . 8. The method according to any one of the claims 5 to 7, characterized in that in the absence of an upshift request after increasing the vehicle speed v _R present at the start of the control intervention of the traction control system by a defined (gear-specific amount) δv an upshift in the vehicle speed v _R + .DELTA.V is performed when the upper upshift threshold v _H2 is smaller than the vehicle speed v _R + .DELTA.V, and the vehicle speed v _R + .DELTA.V smaller than the upper limit v upshift is _H3. 9. The method according to any one of claims 5 to 8, characterized in that the defined (gear-specific) amount δv by which the vehicle speed v _R must be increased for an upshift, the greater the smaller the current gear. 10. The method according to any one of claims 1 to 9, characterized in that the transmission control unit maintains the time t _x for a control intervention of the traction control system after the end of the control intervention of the traction control system. 11. The method according to claim 10, characterized in that the transmission control unit after the end of the control intervention of the drive-slip control system, the maintenance of the status for a control intervention of the drive-slip control system during the time t _x aborts, if the predetermined by the accelerator pedal Throttle valve opening angle falls below a threshold value.