DE19832939A1 - Signal synchronization method e.g. for automatic transmission in motor vehicle - Google Patents

Abstract

The method involves delaying a first signal by a predetermined delay and deriving a control signal from the delayed first signal and at least a second signal. The first signal is delayed with respect to the second signal.

Description

The invention relates to a method for synchronizing at least two Signals, of which at least a second signal versus a first signal has a predetermined time delay, one of the signals derived control signal for controlling, regulating or adapting further Operations. This applies in particular to the operation of a controlled or regulated actuation of an automated clutch or an automated transmission in the drive train of a motor vehicle. The Control or regulation can be an adaptive control or regulation that Deviations from quantities in the operating behavior by an adjustment of Performs control or regulation parameters automatically.

In motor vehicles, the effort for electronic controls and Regulations constantly increasing. The one between a drive motor and a gearbox Coupling arranged in the drive train, for example, is increasing automatically actuated by an actuator actuating the clutch from a  Control unit controlled according to the operating conditions of the vehicle becomes. This enables, for example, automated disengagement and reengagement the clutch when changing gears, engaging when starting the vehicle from a standstill or disengaging the clutch at one Braking process controlled or regulated in the state. Likewise, a Control or regulation of the torque that can be transmitted by the clutch to the engine torque provided by the engine within one Tolerance band are carried out or a slip control, so one Regulation of the difference between the drive speed of the clutch and Output speed of the clutch.

Such automated couplings on the one hand increase ease of use of motor vehicles quite considerably. On the other hand, they contribute to ver reduction in consumption because, especially in connection with automated Manual transmissions are driven more frequently in a fuel-efficient gear. The automated clutch is in an operating mode for reasons low energy consumption of the actuator, short time required for operation and comfort operated so that they essentially only so far is closed as necessary, so that no or no impermissibly high Slip occurs. Knowledge is needed to quickly control the clutch the effective engine torque on the clutch advantageous.  

The effective engine torque on the clutch is determined by the Combustion of the charge arising in the internal combustion engine Combustion torque, such as engine torque, and one when the speed changes the internal combustion engine due to the inertial mass dyna mix moment together. The combustion moment is, for example from at least one of the operating parameters of the internal combustion engine, such as Position of a load control element, accelerator pedal position, throttle valve position, Injection time, injection angle, speed, temperature etc. derived. That's because the dynamic moment of inertia of the internal combustion engine effective especially in clutch slip phases due to the sudden Speed change of the engine plays a role, requires a determination of the Spin of the engine. This size is determined by differentiation of the Obtained engine speed signal. Because of the roughening character of one Differentiation is a smoothing of the engine speed signal before the differentiation by means of filtering advantageous or even necessary. The time delays which every applicable filter algorithm brings with it, result in the Calculation of the torque acting on the clutch to errors that the Control of the torque that can be transmitted by the clutch is essential influence.

The invention has for its object to provide a method that permitted in a control or regulation or in an adaptation process  for example the transmission behavior of control or Control sections to avoid errors caused by the fact that at least two used for the control, regulation or adaptation Signals one with respect to the at least one other is delayed in time. This time delay can be, for example, by filtering at least one signal can be produced by means of a filter.

This task is carried out with the features of the main claim or independent claims 2 and 3 solved. According to the time Offset of the two signals compensated by the fact that the first signal, against which the second signal is delayed by a predetermined period of time, is delayed by the same amount of time, so that the two to generate the Control signals used signals are synchronized or at the same time.

The first signal is advantageously stored and with the predetermined one time delay read out from memory and then with the second Signal merged.

The claim 5 characterizes the implementation of the invention Process that is suitable for a wide variety of problems in its Application to the control of an automated clutch.  

Claim 6 advantageously forms the method according to claim 5 Way further, since those caused by filtering and differentiation Time delays are known and accordingly the first signal or Combustion torque signal are delayed by the predetermined time period can.

The invention is described below with the aid of schematic drawings for example and explained in more detail.

They represent:

Fig. 1 is a diagram of a drive train of a motor vehicle,

Fig. 2 curves showing the delay of a calculated acceleration of the engine speed from the actual acceleration of the engine speed,

Fig. 3 curves that illustrate the errors that result from the time delays in the calculation of the engine acceleration and

Fig. 4 is a block diagram showing the delay of a signal.

Referring to FIG. 1, the drive train of a motor vehicle, an internal combustion engine 2, which is connected via a clutch 4 to a gear 6, which in turn through a propeller shaft 8, and a differential 10 connected to the driven rear wheels 12. The front wheels 14 of the motor vehicle are not driven in the example shown.

The clutch 4 is known per se in its construction and contains, among other things, a clutch disc 16 , which is non-rotatably connected to the crankshaft of the internal combustion engine 2 , a pressure plate 18 , which is non-rotatably connected to the input shaft of the transmission 6 and by means of an actuating lever 20 against the force a plate spring is releasable from frictional engagement with the clutch disc 16 .

The transmission 6 is a conventional manual transmission, which can be shifted by means of a shift lever 22 .

To actuate the actuating lever 20 , an actuator 24 , for example an electric stepper motor, is provided, which is controlled by an electronic control unit 26 . The electronic control unit 26 is known per se in its construction and contains a microprocessor with associated memory devices, interfaces etc. Its input is connected to a position sensor 58 for detecting the position of the actuator 24 or the actuating lever 20 , so that the control unit 26 can regulate a target position of the actuating lever 20 and thus the transmissible clutch torque extremely precisely.

Furthermore, the control device 26 is connected via a data line 30 , for example a CAN bus, to an engine control device 32 , the structure of which is also known per se and contains a microprocessor, memory devices, interfaces, etc.

Operating parameters of the internal combustion engine, for example the temperature from a temperature sensor 34 , the rotational speed from a rotational speed sensor 36 and the position of a throttle valve or a load control member are fed from a load sensor 38 to inputs of the engine control unit 32 . Outputs 40 of control unit 32 control the operation of the internal combustion engine, such as ignition timing, injection quantity, exhaust gas flow rate, etc.

As explained above, it is necessary to give a corresponding control of the clutch 4, to know which acts from the engine to the clutch 4 torque. From this torque, a desired position of the clutch or of the actuating lever 20 is calculated in the control unit 26 , which may depend on further parameters such as the selected gear, wheel speed, clutch slip etc. and determines the actuating lever 20 and thus the torque that can be transmitted by the clutch.

To obtain the necessary information, the control unit 26 is connected to the engine control unit 32 via the data line 30 . The data required for calculating the combustion torque generated by the internal combustion engine 2 as a result of the combustion, such as the position of the throttle valve and speed or a signal proportional to the engine torque or the signal representing the engine torque, are supplied to the engine control unit 26 via the data line 30 . Particularly in the case of rapid changes in speed, the dynamic torque generated by the inertial masses of the internal combustion engine, which is added to the combustion torque when the speed decreases and must be subtracted from the combustion torque when the speed increases.

To calculate the rotational acceleration dw / dt of the engine, the engine speed signal detected by the speed sensor 36 and sent to the control unit 26 via the data line 30 is first filtered or smoothed. For example, a time-discrete, non-recursive filter can be used for the filtering and the subsequent differentiation of the signal. Here, for example, four lines are used to create a best-fit line that is optimized according to the method of least squares. Due to the data rate of data line 30 , the engine speed signal is only renewed every 20 ms when using a CAN bus. The change in the engine speed dn per unit time dt (control interrupt 10 ms) can be determined from the slope of the compensating line.

The following relationship results with the quantities mentioned:

dn = [3.n _mot (t) - 3.n _mot (t - 3dt) + n _mot (t - dt) - n _mot t (t - 2dt)] / 20
dw / dt = (dn / dt). (2.π / 60) = dn / dt.1047 / 100.

The maximum swing-in time of the non-recursive filter results from the time interval between the input speed signals under consideration. If large changes in the speed occur in the input speed signal n _mot , the filtering results in a time shift of the calculated rotational acceleration compared to the actual rotational acceleration.

This state of affairs is shown in FIG. 2, where the time is shown on the abscissa and the speed or the rotational acceleration on the ordinate.

The curve drawn through represents the speed curve of the internal combustion engine represents, the case shown is for example a downshift. The dashed curve represents the calculated spin. The dotted Curve represents the actual spin. As can be seen, lies between the calculated and the actual spin one Time delay of approximately 50 ms.

This time shift of the calculated rotational acceleration compared to the actually occurring one leads to errors in the calculation of the dynamic equilibrium on the motor or the torque acting on the transmission, especially during slip phases. The magnitude of these errors can well be 30 Nm, shown in Fig. 3.

In Fig. 3, the abscissa is again the time, the left ordinate indicates a rotational acceleration and the right ordinate indicates a dynamic torque. The curve drawn through refers to the rotational acceleration and indicates the respective difference between the calculated and the actual rotational acceleration. The dotted curve is calculated from the dashed curve in that the dynamic torque D is calculated from the rotational acceleration and the moment of inertia of the internal combustion engine known in a known internal combustion engine. As can be seen, the error of the dynamic torque in the example shown extends to the order of magnitude of 30 Nm.

As stated, this error is due to the fact that the calculated dynamic torque D is only available at a time which is delayed by approximately 50 ms compared to the actually effective dynamic torque. In order to take into account the total torque acting on the clutch from the engine appropriately for the control or regulation or adaptation of characteristic curves of the operation of the clutch 4 , the combustion torque is included in the calculation of the control signal for the actuator 24 in the control unit 26 with the same delay . This is shown with reference to FIG. 3, which shows how the combustion torque (curve drawn through) calculated on the basis of the data transmitted by engine control unit 32 is delayed by 50 ms (dashed curve) and then added to the dynamic moment (dotted curve) by the Generate total torque, which is used to operate the actuator 24 .

The described calculations of the rotational acceleration and the dynamic torque, for which other algorithms can also be used, and the deceleration of the combustion torque signal can be carried out in the control unit 26 purely in software. Additional hardware modules known per se can also be used for implementation.

FIG. 4 shows a block diagram 100 for explaining the delay of a signal. In block 101 , the combustion torque Me (t) of the internal combustion engine is determined or read out by engine control electronics, which determines this quantity, or detected, for example, via a CAN data bus. The same applies to the engine speed n _mot in block 102 . The signal of the combustion torque Me (t) is buffered in block 103 in an intermediate memory, such as RAM memory, as an M _memory (t). The following representation of the stored values applies with a time delay of 40 ms for one signal:

M _memory (t - 40 ms) = M _memory (t - 30 ms)
M _memory (t - 30 ms) = M _memory (t - 20 ms)
M _memory (t - 20 ms) = M _memory (t - 10 ms)
M _memory (t - 10 ms) = M _memory (t).

The block acceleration dw / dt is determined in block 104 :
dn = [3.n _mot t (t) - 3.n _mot (t - 3dt) + n _mot t (t - dt) - n _mot (t - 2dt)] / 20
dw / dt = (dn / dt). (2.π / 60) = dn / dt.1047 / 100.

In block 105 , the torque M _K applied to the clutch (t-40 ms) at the time (t-40 ms) is determined as:

M _K (t - 40 ms) = M _memory (t - 40 ms) - J _motor .dw / dt

with the moment of inertia J _{motor of} the motor.

In block 106 , this engine torque applied to the input part of the clutch is used as M _K for control, regulation or adaptation.

If more than two signals are common in a further process step process that are delayed to different degrees, this can be done above described methods are applied in that the signals are such be synchronized in which the less strongly delayed signals by the Caching to the maximum amount of the present Delay can be deliberately delayed. This makes time differences  offset by filtering, calculations or other measures with regard to individual signals, which are then processed together become.

The claims submitted with the application are drafted strikes without prejudice for obtaining further patent protection. The The applicant reserves the right to do so, so far only in the description and / or to claim disclosed features.

Relationships used in subclaims point to the others Training the subject of the main claim by the features of respective subclaim; they are not a waiver of attainment an independent, objective protection for the characteristics of the return to understand related subclaims.

However, the subjects of these subclaims also form independent ones Inventions that are one of the objects of the previous Have independent claims independent design.

The invention is also not based on the embodiment (s) of the description exercise limited. Rather, there are numerous variations within the scope of the invention  Rations and modifications possible, especially such variants, elements and combinations and / or materials, for example by combination or modification of individual in connection with that in general Description and embodiments as well as the claims described and features or elements or method contained in the drawings steps are inventive and can be combined into one new object or new process steps or process step follow consequences, also insofar as they relate to manufacturing, testing and working processes.

Claims (6)

1. A method for synchronizing at least two signals, of which at least a second signal and possibly further signals have a predeterminable time delay compared to a first signal, a control signal derived from the signals being used to control, regulate or adapt further processes, characterized by its special design and mode of operation in accordance with the present application documents. 2. Method for synchronizing at least two signals, one of which at least one second signal compared to a first signal has predetermined time delay, one of these Control signal derived for control, regulation or Adaptation of further processes is used, characterized in that that the first signal is delayed by the predetermined time delay is and the control signal from the delayed first signal and at least the second signal is derived.   3. Method of synchronizing two signals, one of which is a second Signal compared to a first signal a first predetermined time Has a delay, one derived from both signals Control signal for controlling, regulating or adapting further processes is used, characterized in that the first signal around the predetermined time delay is delayed and the control signal derived from the delayed first signal and the second signal becomes. 4. The method according to any one of claims 1 to 3, characterized in that the first signal is stored and with the predetermined time Delay is read out. 5. The method according to any one of claims 1 to 4, characterized in that the first signal is one of operating parameters Internal combustion engine-derived combustion torque signal, such as Engine torque signal, is that the second signal is on off Engine speed derived dynamic changes Moment signal is and that that from the delayed first signal and control signal derived from the second signal is an operation of a automated clutch controlling signal.   6. The method according to claim 5, characterized in that the second Signal by filtering the measured engine speed signal and Differentiation of the filtered engine speed signal is derived.