DE10313483A1 - Monitoring gear selection or ratio in vehicle automatic gears, repeatedly compares input- and output speeds with desired ratio at all times - Google Patents

Abstract

The actual gear ratio is compared with the desired ratio. On difference, a failure is detected. The failure number of the relevant gear component is then incremented. When this number exceeds a given maximum value, a symptom or fault is identified and a reversionary mode is introduced. To monitor the actual gear ratio, the input and output speeds of the gearbox are measured. The ratio- or gear selection monitoring, takes place outside gear changes, during gear changes and/or during gear engagement.

Description

The present invention relates to a process for translation or gait monitoring for a Automatic transmission or an automated manual transmission of a motor vehicle according to the generic term of claim 1.

The ever increasing complexity of in automobiles used automatic transmissions (with and without converter) and automated Manual transmissions place ever higher demands on the corresponding diagnostic and surveillance systems. Diagnostic and monitoring systems are to be used here primary guarantee personal protection and driving safety; another goal is the guarantee vehicle availability and the protection of the transmission and its components.

With today's automatic transmissions and automated manual transmissions (e.g. automated manual transmissions or double clutch gearbox) according to the state of the art the protection mechanisms increasingly in the software and hardware of the electronic transmission control integrated. Especially with the so-called shift by wire systems, in which the driver no longer Intervening directly in the system are very special requirements to the protection and monitoring mechanisms posed.

Hydraulic locks, which in earlier Gearboxes are no longer possible because through multiple use of clutches in the different gears on the mechanical side is a difficult task; moreover is the use of hydraulic locks cost-intensive and space-intensive.

Safety systems for automatic transmissions are known from the prior art. For example, the DE 196 01 618 A1 proposed by the applicant to detect malfunctions outside the circuits by monitoring the measured transmission input and output speeds. Then the current gear is switched to a replacement gear, which is the next highest if possible; if the current gear is the highest, then the next lower gear is selected. As part of the DE 196 01 618 A1 a symptom counter is provided for each gear, which is incremented by one if a malfunction is present, an emergency driving program being activated when a predetermined limit value for the symptom counter is exceeded.

This procedure according to the state The technology results in gear systems in which a clutch or brake in several gears in a row is switched, in the event of a malfunction on one of these switching elements, in several circuits and subsequent detection of malfunctions, before a safe operating state is reached. The same goes for also for gear systems with recurrent activation of the same switching element in the next Gear, in which case for a safe state is reached for a short time; however, from the system at the next Up or down shift again tried a switching element with no longer available function to bring into the flow of power.

In the state of the art known method is monitoring outside of the circuits performed; a surveillance while the switching process or gear selection is not provided.

The present invention lies based on the task, based on the prior art mentioned a process for translation or gait monitoring for a Automatic transmission or an automated manual transmission one To specify motor vehicle, which has the disadvantages of the prior art avoids. The method according to the invention should also for Gearboxes with multiple use of clutches and brakes can be used be and after detection of a fault, replacement measures initiate to keep the transmission system in a safe condition, or to bring them into a safe state.

In addition, the inventive method a surveillance also during ensure the switching process or gear selection.

This task is due to the characteristics of claim 1 solved. Other variants and advantages go. from the subclaims.

Accordingly, a procedure for gait monitoring for a Automatic transmission or an automated manual transmission one Motor vehicle proposed in which the actual translations based on of the measured input and output speeds, with the target translations be compared. If the actual translation - including permissible tolerances - from the target translation deviates, are alternative measures initiated, in the context of a preferred variant of the method an error after repeated occurrence of this deviation in one Course or during a circuit is recognized, so that only then replacement measures be initiated. Therefore, in the following a deviation is considered Fault defined; if exceeded a predetermined number of faults an error or a symptom is recognized, the predefined Number of faults can also take the value zero, making a one-time deviation or disturbance is treated as an error.

After an error has been detected, the system is brought into a safe state and the error is stored in the diagnosis management; in the further procedure is defined in the diagnosis management on the basis of the error pattern.

Here is according to a particularly advantageous Variant of the method according to the invention the type of transfer to a safe state depends on the number of errors or symptoms. At the Occurrence of a fault or an error outside or a fault counter is incremented within circuits. exceeds the fault counter one predetermined maximum value, as already explained, then an error or symptom recognized, a symptom counter incremented and into a replacement gear switched, whereby for a symptom counter is provided for each switching element or circuit. With multiple Recognize symptoms outside of circuits or during Circuits, e.g. when the symptom counter reaches a maximum value, a replacement program is activated.

According to the invention, a as safely detected gear "carried", so that this Gear is switched when an error is detected.

The invention is illustrated below the attached Figures closer by way of example explained. They represent:

1 : A representation of the target gear ratios and the gear ratio tolerance bands for two gears x and y and the actual gear ratio for gear x as a function of the output speed n_ab;

2 : A representation of the gear ratio tolerance band for an upshift from gear x to gear y and the actual gear ratio as a function of time;

3 : A representation of the curves of the clutch pressures for the gears x and y during the 2 shown upshift as a function of time;

4 : A representation of the translation tolerance band for engaging gear y and the actual translation as a function of time; and

5 : A representation of an exemplary time course of a clutch pressure during the in 4 shown gear shifting y.

Within the scope of the method according to the invention it is envisaged that the translation or gait monitoring not just outside the circuit but also during of switching operations and during gear shifting becomes.

It will be the actual translations based on measurements of the input and output speeds and with the target translations compared. If the actual translation - including permissible tolerances - by the Target speed deviates, are alternative measures initiated.

According to the invention, based on the tolerance specifications of the input and output speed for each gear, a permissible gear ratio tolerance band is calculated, which in 1 is represented by the lines i_Gang_x_ob (upper limit) and i_Gang_x_un (lower limit) for the aisle x and the lines i_Gang_y_ob (upper limit) and i_Gang_ y_un (lower limit) for the aisle y. Again 1 it can be seen that these lines envelop the actual fixed gear ratio (target gear ratio) i_Gang_x_fest or i_Gang_y_fest, which is determined by the gears in the respective gear.

When driving in one gear and the calculated translation, which about the output speed and the turbine speed is determined in the translation tolerance band then it is assumed that the gearbox or the System is working properly. This is the actual translation i-Gang_ calculated from the quotient turbine speed divided by the output speed is calculated.

If now the calculated actual translation is not within the specified tolerance band, then it is assumed that there is a malfunction. A disturbance could e.g. be that a clutch that is in the flow of power, the moment not broadcast can and slips because the clutch is defective or because of the necessary Pressure in is defective or because of the necessary pressure in the clutch not present or because a speed sensor is defective.

When a deviation occurs an error counter is incremented. exceeds the fault counter one predetermined maximum value, then a symptom or error is recognized. No interference occurs on, the fault counter opens decremented in a predetermined manner (until it has the value zero). When changing to a new actual gear, the fault counter is also set to zero.

If a symptom or error is recognized, symptom counters are incremented according to the invention, wherein for each Switching element each has a symptom counter. In doing so the respective symptom counters of the clutches involved in this gear increased by one.

Is a symptom or error detected? an error code is stored in the controller's error memory or entered in the diagnosis management. At the same time, the Diagnostic software communicated the replacement gear to be inserted. Diagnostic management then determines the equivalent gear and solves the shift in the shift sequence control out.

According to the invention, the predetermined maximum value the fault counter zero so that any deviation is classified as an error. If not recognized of a symptom in the actual aisle and a subsequent switching, the symptom counter becomes Shift start reset to zero.

After detecting an error, is changed to a corresponding safe state depending on the situation. This can e.g. be a gear that still allows based on the speeds is, but in which in the current faulty gear in the power flow lying couplings are not involved.

The monitoring according to the invention can be carried out both in the Forward gears as well also in reverse or in reverse gears (if available).

The method presented here can also be used during a shift. In this case, the calculated actual translation, as in 2 shown using the example of an upshift, also compared with the corresponding permissible tolerance specifications. If the last predefined translation tolerance band is not left, then it is assumed that the shift or the shifting process is OK. If the tolerance band is left during the shift, for example because the clutch to be shifted cannot transmit the torque (the ratio increases when the engine is in train operation), a corresponding safety measure is initiated. The same applies, for example, even if the disengaging clutch cannot reduce the torque, which can result in the old gear ratio not being left, in which case the gear ratio would also increase and the tolerance band would be left.

If an incorrect clutch is engaged, then there is at the end of the switching process - in individual cases already before - one other than the allowed translation. In this case too, the calculated actual translation is used leave the specified tolerance band, so that according to the invention in one safe state passed becomes.

If a There is a fault a fault counter is incremented. exceeds the fault counter one predetermined maximum value (which can also be zero), then a Symptom or error detected. If there is no fault, the fault counter is decremented (until it is zero). The fault counter also becomes active at the start of switching set to zero.

If a symptom is detected, symptom counters are incremented. For every A symptom counter is available for each circuit. The respective symptom counter the associated circuit increased by one.

If a symptom has been identified, an error code entered in the error memory. At the same time the diagnostic software is informed of the replacement gear to be inserted. The Diagnostic management then determines the replacement gear and triggers the circuit by a signal in the switching sequence control. All symptom counters will be according to the invention at restart (ignition OFF / ON) initialized to the value zero.

If a shift in a particular Gait fails after a certain number of attempts, then is changed to a permanently safe state; advantageously this circuit is no longer specified. For example, it can be driven in the current gear, or it will only be certain circuits allowed, which in turn analog by means of Procedure controlled.

The lower tolerance curve of the translation tolerance band is based on a suitable algorithm lake or a calculation rule derived from the lower tolerance value of the old gear; Similarly the upper tolerance curve is based on another calculation rule derived from the upper tolerance value of the old gear, the calculation instructions based on system events - for example by reaching discrete phases of the current circuit - in their temporal sequence can be influenced.

In 3 the clutch pressure curve is shown during the upshift; the clutch pressure (curve A) in the shift element involved in gear x decreases and takes the value zero, while the clutch pressure in the shift element involved in gear y increases to take on a constant value (curve B).

If multiple circuits, so-called nested Circuits that are carried out in succession must be in the transition area from one to the next Circuit when recognizing an impermissible translation, the error is clear be assigned to a circuit, so that according to the invention when it occurs of an error, this of the corresponding circuit or the corresponding clutch system is assigned, whereby the replacement functionality corresponding to this error is called can be.

During gear engagement, the gear ratio tolerance band of the target gear is specified as the target tolerance band according to the method according to the invention. This is in 4 illustrates which of the translation tolerance band as well as the actual translation for shifting gear y shows. The corresponding clutch pressure curve is the subject of 5 (Curve C). The permissible tolerance band during gear selection is determined on the basis of the output speeds using appropriate specifications, whereby these specifications can be based, for example, on the current speeds, load positions (engine torque / accelerator pedal, throttle valve ...). If the specified translation tolerance band is not left here, too, it is assumed that the gear engagement is OK. If the specified tolerance band is left, it is assumed that there is an error.

The response to the mistake can e.g. reloading the neutral position. Another one Gear can according to one Variant of the invention e.g. only allowed after a certain time if there is a driver request. The gear fails despite several attempts, it is assumed that the concrete Gear engagement is permanently buggy, making it a safer State is permanently specified.

Alternatively, according to the invention, a gear other than the desired gear can be switched , whereby here, too, the calculated actual translation is used to check whether the newly selected gear can be engaged. The rest of the process is then the same as for the last gear tested.

According to an advantageous variant of the method according to the invention will switch to a replacement gear if a symptom is outside is recognized by circuits, as follows: When detected Symptom is shifted up one gear. The replacement gear is so according to the invention the next higher gear with the exception of the replacement gear for the highest Gear, which is the next lower Gear is. In the R gear, Neutral is specified as a substitute gear, if there is only one R-gear.

The gear requirement through the replacement gear is a default for the diagnostic management, where the priority of the gait specified becomes. This gives a signal to the switching sequence control. results out of the signal that the translation monitoring calls for an "alternative gear", this will with a higher priority than that Torque protection, maintaining gear or reversing a shift through translation monitoring treated. Here is the downshift prevention not turned off.

If a symptom or error occurs during a Circuit is detected, then the circuit is canceled and the replacement gear without shifting sequence (conversion of the actuators to the replacement gear combination).

Outside of circuits according to one particularly advantageous variant of the invention provided by the replacement gear to switch to normal gear when the target gear is higher or is equal to the actual gear or if the output speed is less than one predetermined threshold is and at the same time dki less than a predetermined Threshold is. It is also possible to switch to normal function if the position is neither D nor R. After a fault detection in the R-gear becomes normal function returned if a driver request other than R is recognized.

While a shift is provided, from the equivalent gear to the normal gear to switch when the position N / R / P has been recognized or a predetermined one Delay Time has expired.

Furthermore, it is part of a Further development of the invention provided that in the event of multiple recognition of symptoms outside of circuits an error memory entry with an associated replacement program he follows. Is a predetermined maximum value for symptoms of several at the same time symptom counters reached, then an error memory entry of the involved takes place Couplings with an associated one Replacement program for the error entries.

If a symptom is detected during circuits then the corresponding one symptom counter incremented. This symptom counter is with the maximum allowable Number (maximum value) of symptoms, depending on the circuit, compared. If the number is less than the maximum value, the Diagnostic interface of the errors entered in the error memory and the related one Replacement gear to be engaged is transmitted, as already explained. is the value of the symptom counter is equal the maximum value, then takes place via the diagnostic interface sends a corresponding message to the diagnostic software, then the corresponding one Substitute function of a substitute program activated. At the same time in the depending on the circuit type Made a corresponding error entry.

A re-filtering is according to the invention the error memory entries provided which outside of circuits is preferably activated every 100 ms. in this connection is checked to everyone Actual a counter provided that records the number of all symptoms while driving. moreover it is stored whether the respective gear has already been checked by the translation monitoring.

If outside of circuits all Passages through translation monitoring checked have been and no symptom has been recognized in any gear, then an error memory entry is no longer indicated by a symptom set present.

Be in a hallway where one certain clutch is involved, one time the test conditions fulfilled in the gear engaged, then this is cached even if the test conditions be left again. Then there is a gear change without Symptom, the fault memory entry is withdrawn.

While a circuit finds a back filtering of a symptom with the return to normal function instead; the back filtering a fault memory entry is made at the end of the circuit, where the following conditions apply: An error code is then on error not set if the test in the associated circuit and the associated monitoring function became active and no error was detected.

i Gang_x_ob

upper Limit or curve of the translation

Zung tolerance band for the Gear x

i_Gang_x_un

lower Limit or curve of the translation

Zung tolerance band for the Gear x

i_Gang_x_fest

fixed translation for the aisle x, firm

placed through the gears

i_Gang_berechnet

calculated Is translation

n_ab

Output speed

A

Clutch action switch off the

the switching element

B

Clutch action to switch on

the switching element

C

Clutch action while of the aisle

insertion

Claims (24)

Method for gear ratio or gear monitoring for an automatic transmission or an automated manual transmission of a motor vehicle, characterized in that the actual gear ratio is compared with the target gear ratio and that if the actual gear ratio deviates from the target gear ratio, a malfunction is detected and at least a malfunction counter of the switching elements involved is incremented, whereby if the malfunction counter exceeds a predetermined maximum value, a symptom or error is recognized and replacement measures are initiated, the actual translation being recorded by measuring the input and output speeds and the translation or Gear monitoring outside of gear changes, during gear changes and / or during gear engagement. A method according to claim 1, characterized in that after detecting a symptom, the system is in a safe Condition transferred and the Error in the diagnosis management is saved, whereby in the Diagnosis management based on the error pattern defines the further process becomes. A method according to claim 1 or 2, characterized in that that switched to a replacement gear after the detection of a symptom becomes. Method according to one of the preceding claims, characterized characterized that at least after the detection of a symptom a corresponding symptom counter is incremented, when the symptom counter reaches a predetermined maximum value reached, a replacement program is activated and each switching element and each circuit a symptom counter assigned. Method according to one of the preceding claims, characterized characterized that if there is no disturbance of the Fault counter on is decremented in a predetermined manner and that with a change the corresponding fault counter is set to zero in a new actual gear. Method according to one of the preceding claims, characterized characterized in that the predetermined maximum value of the fault counter Value is zero. Method according to one of the preceding claims, characterized characterized that for a translation tolerance band for each gear is calculated, which is by means of a lower and an upper tolerance curve the curve of the target translation wrapped up like this that when the values for the actual translation within of the translation tolerance band the condition is classified as error-free or trouble-free. A method according to claim 7, characterized in that the translation tolerance band based on tolerance specifications for Input and output speed is calculated. Method according to one of the preceding claims, characterized characterized that when outside an error is detected by circuits, shifted into gear which is still allowed based on the speeds and at which the Clutches lying in the power flow in the current faulty gear are not involved. Method according to one of the preceding claims, characterized characterized in that when a shift occurs in a particular Walk after a certain predetermined number of attempts fails, is transitioned to a permanently safe state. A method according to claim 10, characterized in that when a gear shift into a particular gear after a certain predetermined number of attempts, this circuit fails is no longer specified. Method according to one of the preceding claims, characterized in that, if a plurality of circuits are carried out in succession, upon detection of an impermissible translation in the transition area from one circuit to the next, the errors are clearly assigned to a circuit on the basis of predefined decision criteria is arranged so that the replacement functionality corresponding to this error can be called. Method according to one of the preceding claims, characterized characterized that during the Gear insert the tolerance band of the target gait as the target tolerance band is specified. A method according to claim 13, characterized in that the allowable Tolerance band during gear selection based on the output speeds via corresponding specifications is determined. A method according to claim 14, characterized in that the specifications of the current speeds and load positions depend. Method according to one of claims 13 to 15, characterized in that that when a fault is detected while in gear, the Reloading the neutral position is performed, with a renewed Gear is allowed after a predetermined time. Method according to one of claims 13 to 14, characterized in that that if a fault is detected during gear engagement in a gear other than the desired gear is switched if based on the calculated actual translation this gear can be engaged. Method according to one of the preceding claims, characterized characterized that the lower tolerance curve during a switching operation of the translation tolerance band based on an algorithm lake or a calculation rule from the lower tolerance curve of the old gear is derived and that the upper tolerance curve of the translation tolerance band based on an algorithm lake or a calculation rule from the lower tolerance curve of the old gear is derived, whereby the calculation rules based on system events in their temporal sequence can be influenced. Method according to one of the preceding claims, characterized characterized that monitoring in forward gears and / or in reverse or in reverse gears if several reverse gears provided are done. Method according to one of the preceding claims, characterized characterized that for all gears except the highest Ganges the replacement gear the next higher gear is that for the highest Gear the replacement gear the next is lower gear and that for the reverse gear the replacement gear is neutral, whereby when shifting into the replacement gear outside of circuits this circuit has a higher priority than that Torque protection, maintaining gear or reversing a shift through translation monitoring has and when switching to the spare gear during a Switching the replacement gear without switching the actuators to the Replacement gear combination is inserted. Method according to one of the preceding claims, characterized characterized that a shift from the equivalent gear to the normal gear outside of circuits then performed becomes when the target gear is higher or is the same as the actual gear or if the output speed is lower than a given threshold and at the same time dki less than one predetermined threshold, or if the position is neither D nor R is, after a fault detection in the R gear to normal function is returned if a driver request other than R is recognized. Method according to one of the preceding claims, characterized characterized that a shift from the equivalent gear to the normal gear while a circuit then performed if the position N / R / P was known or a predefined one Delay Time has expired. Method according to one of the preceding claims, characterized characterized that a counter is provided for each checked actual gear is that records the number of all symptoms while driving and that is filed whether the respective gear has already been checked by the translation monitoring, being if outside of circuits all gears checked have been and no symptom has been recognized in any gear Error memory entry for a symptom is set to no longer available and what if in a corridor in which a certain switching element is involved, once the test conditions Fulfills are, this is cached even if the test conditions be left again and without a symptom when the gear is changed the fault memory entry is withdrawn becomes. Method according to one of the preceding claims, characterized characterized that during a Circuit a back filtering carried out such that a symptom is cleared upon return to normal function and that at the end of the circuit an error code does not indicate errors is set if the test in the associated circuit and the associated monitoring function became active and no error was detected.