Method for controlling and / or regulating a drive train of a motor vehicle

Abstract

The invention relates to a method for controlling and / or regulating a drive train of a motor vehicle, wherein the drive train has at least one drive motor and at least one transmission, wherein the drive motor can be effectively coupled and / or is effectively coupled to the transmission, wherein at least two gear stages, each with a fixed transmission ratio, can be set and / or selected by means of the transmission, and wherein during a shifting operation from one of the gear stages to another of the gear stages at least one power (P) of the drive motor is controlled and / or regulated. An application for controlling and / or regulating can be implemented with little effort by forming a quotient (q) from a numerator and a denominator, whereby the numerator is derived from a difference between a current measured actual speed (n ist ) of the prime mover and a target speed (n z) of the drive motor for the end of the switching process (t E ), where the denominator is the amount of a difference between a value measured at the beginning of the switching process (t A ) measured speed (n aus ) of the prime mover and the target speed (n z ) of the drive motor for the end of the switching process (t E ), in particular where the quotient (q) is calculated according to the formula q = nist − nz | ( naus − nz ) | is calculated and / or determined, wherein the power (P) of the drive machine is controlled and / or regulated during the switching process as a function of this quotient (q).

Description

[0001] The invention relates to a method for controlling and / or regulating a drive train of a motor vehicle with the features of the preamble of patent claim 1.

[0002] Typical drive trains of motor vehicles have at least one prime mover, in particular an internal combustion engine and / or an electric motor, and at least one transmission. The prime mover can be effectively coupled and / or is effectively coupled to the transmission, in particular by means of a clutch. By means of the transmission, at least two gear stages, each with a fixed transmission ratio, can be set and / or selected. During a shift from one of the gear stages to another of the gear stages, at least one power of the prime mover is controlled and / or regulated. In particular, an actual power of the prime mover, i.e. a power of the prime mover currently produced by the prime mover and which can also be measured, is controlled and / or regulated.

[0003] DE 695 22 797 T2 discloses a method for controlling and / or regulating a drive train of a motor vehicle having an electric motor during a gear shift from one gear to another of the gears of a transmission of the motor vehicle. In a first step of the method, after the start of the gear shift, the torque of the electric motor is initially adjusted to a first value for an upshift or to a second value for a downshift, and the transmission is shifted into neutral. In a second step of the method, the torque of the electric motor is adjusted to a value associated with the target speed of the electric motor for the end of the gear shift. The target speed depends on the gear ratio of the target gear. In a third step, after completion of the second step, the transmission is shifted into the target gear.In a fourth step, after completion of the third step, the torque of the electric motor is gradually changed to a torque that corresponds to the position of an accelerator pedal of the motor vehicle.

[0004] DE 10 2004 027 062 A1 discloses a method for controlling and / or regulating a drive train of a motor vehicle with an automatic transmission, which prevents gearshift oscillation in critical gradient situations. For this purpose, the actual transmission input power and the actual transmission input torque are calculated or determined as a function of the engine speed, with the optimal upshift point or the beginning of the gearshift process being determined based on the criterion of equal wheel power or equal tractive force or equal wheel torque at the end of the gearshift process.

[0005] DE 100 10 815 A1 describes a method for controlling and / or regulating a drive train of a motor vehicle with an internal combustion engine (referred to as the engine) and with an automatic dual-clutch transmission. During a gear shift, a control torque obtained from a closed-loop control system is added to a static engine torque and a dynamic engine torque specified by a control system. The dynamic engine torque is a function of a target shift time, a flywheel mass or mass moment of inertia of the engine related to the transmission input side, and a differential speed. The differential speed results from the ratio of the gear ratio effectively engaged before the gear shift and the gear ratio effectively engaged after the gear shift, multiplied by the transmission output speed.The additional control torque ensures that the speed of the speed reduction is maintained, i.e. the control keeps the speed of the speed reduction constant, whereby a constant transmission input speed change results in the advantage of a continuous output torque curve with the highest level of shifting comfort.

[0006] DE 11 2007 000 849 B4 shows a method for adapting the control of the clutches of a dual-clutch transmission, in which, during a gear shift, the torque transmittable by the opening clutch and the torque transmittable by the closing clutch are controlled according to target curves, during the gear shift a difference between a target value and an actual value is determined and the target curve of at least one of the clutches is adapted for a subsequent gear shift in the sense of reducing the difference between the target value and the actual value.

[0007] With the known methods for controlling and / or regulating a drive train of a motor vehicle during a gear shift, a problem arises in that during different gear shifts between different gear ratios, gear steps of different sizes sometimes have to be implemented. During such a gear shift, the difference between the speed of the prime mover measured at the start of the gear shift and the target speed of the prime mover for the end of the gear shift can be / become quite large. In particular, conventional transmissions are designed in such a way that smaller gear steps have to be implemented between higher gear ratios than between lower gear ratios. For gear shifts of different sizes, the control and / or regulation of the drive train must then be adapted or designed separately for each different size gear shift.In particular, for each gear step of varying size, appropriate tests must be conducted in advance on a drive train, and the resulting control and / or regulation parameters must be stored in a control and / or regulation device. This so-called "application" is therefore correspondingly complex, both in the described determination of the control and / or regulation parameters and in the design and / or programming of the associated control and / or regulation device.

[0008] The invention is therefore based on the object of designing and / or developing the method for controlling and / or regulating a drive train of a motor vehicle in such a way that the problems of the prior art are eliminated or at least reduced, in particular whereby an application for controlling and / or regulating the drive train can be carried out with less effort.

[0009] This object underlying the invention is now initially achieved by a method for controlling and / or regulating a drive train of a motor vehicle with the features of patent claim 1.

[0010] One aspect of the invention is essentially that a quotient q is formed from a numerator and a denominator, the numerator being a difference between a current measured actual speed n ist the prime mover and a target speed n z of the drive motor for the end of the switching process, where the denominator is the amount of a difference of a speed n measured at the beginning of the switching process aus the drive machine and the target speed n z of the drive motor for the end of the switching process, in particular the quotient is calculated according to the formula q=nist−nz|(naus−nz)| is calculated and / or determined, whereby the power of the drive machine is controlled and / or regulated during the switching process as a function of this quotient q.

[0011] This quotient q now "normalizes" all gear steps. This makes the application much simpler. The control and / or regulation only needs to be designed for one gear step and, in particular, corresponding tests only need to be carried out on a drive train for one gear step, and the control and / or regulation parameters determined therein need to be stored in a control and / or regulation device of the drive train. Nevertheless, high-quality control and / or regulation is carried out for all different gear steps, precisely by controlling and / or regulating the power of the drive motor during the gear shift as a function of the quotient q. Using the quotient q, the gear shift can still be implemented in a particularly short time for all gear steps.

[0012] Preferably, a setpoint for the power of the drive machine is calculated as a function of the quotient q. By incorporating the quotient q into the setpoint power, the control and / or regulation is further simplified.

[0013] In an advantageous embodiment of the method, the quotient q is calculated and / or determined several times in succession during the gearshift process, in particular at specific time intervals. In particular, the actual speed n ist of the drive machine is determined quasi continuously with a certain sampling rate and then the quotient q for each determined value of the actual speed n istThe quotient q is calculated and / or determined during the switching process at least as often, in particular at appropriate time intervals, so that, on the one hand, sufficiently precise control and / or regulation is possible and, on the other hand, the effort required to determine and / or calculate the associated values such as the quotient q is acceptably high.

[0014] Preferably, a manipulated variable for the power of the drive machine is calculated as a function of at least one control and / or regulating parameter. In particular, the control and / or regulating parameter has the same values and / or a same value progression for each change from one of the gears to any other gear. This further simplifies the application. The corresponding tests on the drive train are particularly easy to carry out due to the relationship between the control and / or regulating parameter and the manipulated variable for the power. In particular, sensors required for determining measured values, such as speeds, during drive train operation can also be used.

[0015] According to a further embodiment of the method, the control and / or regulation of the power of the drive engine as a function of the quotient q is terminated when the quotient q has a value of substantially zero. Subsequently, in particular after completion of the gearshift process, the power of the drive engine is then controlled and / or regulated as intended for normal operation, e.g., as a function of the position of an accelerator pedal of the motor vehicle. If the quotient q has a value of substantially zero, then the actual speed n ist the drive machine the target speed n z of the drive motor is essentially achieved. This avoids torque jumps in the drivetrain at the end of the gearshift.

[0016] Advantageously, different values of the quotient q are each assigned a value of a parameter a, in particular with the aid of a characteristic map. The target power value is adjusted depending on the parameter a. In particular, the value of the parameter a becomes a target preset value for the power P SV to form and / or calculate the target power value. This further reduces the effort required to control and / or regulate the power of the drive motor during the gearshift process, depending on the quotient q. In particular, only particularly simple calculations need to be performed.

[0017] According to a further, in particular alternative, embodiment of the method, the value of the parameter a is determined with an intervention power P, which is specified in particular with the aid of the transmission control unit. Eg This product is then multiplied to the target value of the power P SVto form and / or calculate the target value of the power p soll In particular, the setpoint power P soll then according to Formula P soll = P sv + P Eg × a is calculated and / or determined. This further simplifies the application.

[0018] It can be advantageous if, for an intermediate value of the quotient q present between the different values of the quotient q, an associated intermediate value is interpolated from the two respective adjacent values of the parameter a, in particular by means of a linear approach function or a different type of approach function. For example, a polynomial function with a degree higher than two, such as three, could also be selected as the approach function. Through interpolation, the effort required to determine the parameter a within the scope of the application is further reduced while maintaining high accuracy. The high accuracy of the parameter a for the switching processes then leads in particular to a high quality of the control and / or regulation during the switching processes.

[0019] According to a further preferred embodiment of the method, the power setpoints and / or values of parameter a are constant during a central time period of the switching process. This allows the control and / or regulation of the power of the drive motor during the switching process to be further simplified. With the same power setpoints, assuming no or only minor disturbances, no or only minor changes in the manipulated variable are necessary.

[0020] In order to avoid torque jumps in the drive train and to further improve driving comfort throughout the gearshift, the target power value at the beginning of the gearshift essentially corresponds to the target power value at the end of the gearshift.

[0021] There are now numerous possibilities for advantageously designing and developing the method according to the invention for controlling and / or regulating a drive train of a motor vehicle. Reference is made in this regard to the claims subordinate to claim 1. A preferred embodiment of the method according to the invention for controlling and / or regulating a drive train of a motor vehicle will now be explained and described in more detail with reference to the drawing and the associated description. The drawing shows: Fig. 1 shows schematically the curves of the actual speed of the drive motor, the quotient q and the value of the power of the drive motor during a gear change designed as an upshift, and Fig. 2 shows a schematic representation of the curves of the actual speed of the drive motor, the quotient q and the value of the power of the drive motor during a switching process designed as a downshift.

[0022] Based on the Fig. 1 and Fig. 2 describes a method for controlling and / or regulating a drive train of a motor vehicle.

[0023] Fig. 1 and Fig. 2 shows in particular the curves as a function of time t.

[0024] The drive train comprises at least one prime mover, in particular an internal combustion engine and / or an electric motor, and at least one transmission. The prime mover can be effectively coupled and / or is effectively coupled to the transmission, in particular by means of a clutch. By means of the transmission, at least two gear stages, each with a fixed gear ratio, can be set and / or selected. During a shift from one of the gear stages to another of the gear stages, at least a power P of the prime mover is controlled and / or regulated. The gear stages are designed, in particular, by means of gear pairs. However, it would theoretically also be conceivable to use a transmission which, although mechanically continuously operable, nevertheless has fixed gear ratios through appropriate control of the transmission. The aforementioned clutch is, in particular, controlled automatically. E.g.An automated dual-clutch transmission could be used for the process. The transmission, in particular, has a number of different gear ratios, particularly five to seven gears.

[0025] A quotient q is formed from a numerator and a denominator. The numerator is calculated from the difference between a current measured actual speed n. ist the prime mover and a target speed n z the drive motor for the end of the switching process t E The denominator is calculated from the difference between the values of the switching process t A measured speed n aus the drive machine and the target speed n z the drive motor for the end of the switching process t E In particular, the quotient q is calculated according to the formula q=nist−nz|(naus−nz)| calculated and / or determined. The power P of the drive machine is controlled and / or regulated during the gearshift process as a function of this quotient q. The quotient q is formed in particular with the aid of a control and / or regulating device of the motor vehicle, in particular with the aid of a transmission control unit and / or a drive machine control unit. Such a control and / or regulating device comprises in particular an electrical and / or electronic data processing system, in particular a computer, with the aid of which the quotient q is formed and / or calculated by executing a corresponding program code. The control and / or regulating of the power P of the drive machine is also carried out in particular with the aid of the control and / or regulating device comprising the electronic data processing system.

[0026] The switching process starts at a time t Aof the start of the switching process, at which the drive motor with the then measured speed n aus rotates. The switching process ends at a time t E the end of the switching process, to which the drive motor with the then measured target speed n z rotates. The target speed n z the drive motor for the end of the switching process t E However, it can also be calculated and / or determined in advance at the beginning and during the gear shift using the two gear ratios of the gear effectively engaged before the gear shift and the gear effectively engaged after the gear shift.

[0027] Fig. 1 and Fig. 2 show four time points c 1-4 during the switching process, which are successively between the time t A the start of the switching process and the time t Ethe end of the gearshift process. If the drive motor is designed as an internal combustion engine, the power P of the drive motor can be controlled and / or regulated, for example, by a throttle position of the internal combustion engine.

[0028] A setpoint of the power P soll of the prime mover is calculated as a function of the quotient q. This setpoint power P soll of the drive machine leads to the fact that due to the power P soll carried out control and / or regulation, then the Fig. 1 and Fig. 2 shown power P of the drive machine or its curve is achieved.

[0029] The quotient q is calculated and / or determined several times in succession during the gearshift process, in particular at intervals of specific time intervals. The time intervals are particularly small enough to allow a quasi-continuous progression of the values of the quotient q, and in particular the quotient q is thus available in real time. At least, however, the time intervals are small enough to allow a sufficiently high quality of control and / or regulation. It is conceivable that the time intervals in areas of larger changes in the actual speed n ist are smaller than in areas of smaller changes in the actual speed n ist , the time intervals therefore depend on a gradient of the actual speed n ist are.

[0030] A manipulated variable for the power of the drive machine is calculated as a function of at least one control and / or regulation parameter. In particular, the control and / or regulation parameter has the same values and / or a same value curve for each change from one of the gears to any other gear. The power of the drive machine is controlled, for example, using a P-, I-, or D-control system or any combination of such controls. In this case, a so-called gain, an integral-action time and / or a derivative-action time are used as control and / or regulation parameters. The use of other types of control and / or regulation is also conceivable, however. The control and / or regulation parameter is determined in advance as part of the so-called application in tests on the drive train, for example using at least one step response of the drive train.By “normalizing” the gear steps using the quotient q, the testing effort during this application is advantageously minimized or at least significantly reduced.

[0031] The control and / or regulation of the power P of the drive motor as a function of the quotient q is terminated when the quotient q has a value of essentially zero. When upshifting according to Fig. 1, the quotient q runs from a value of 1 to the time t A of the beginning of the switching process falling to a value of zero at the time t E . of the end of the gearshift. When downshifting according to Fig. 2, the quotient q runs from a value of -1 to the time t A of the start of the switching process rising to a value of zero at time t Eof the end of the gearshift. The quotient q thus has positive values for upshifts and negative values for downshifts.

[0032] Different values of the quotient q are each assigned a value of a parameter a, in particular with the help of a characteristic map. This assignment is shown in Fig. 1 and Fig. 2, each of which is shown next to the curves of the quotient q in the form of a characteristic map presented as a table. This assignment is determined, in particular, during the application process and stored and / or saved in the control and / or regulating device, in particular in a data memory of the control and / or regulating device.

[0033] The setpoint power P soll is adjusted depending on the parameter a. In particular, the value of the parameter a becomes a target value P SV of the power to form and / or calculate the target value of the power P sollThe target value of the power P SV is, in particular, a fixed value. However, in certain applications, it is also conceivable that the target value P SV is not a constant value, especially when it is calculated and / or determined depending on various other parameters. The target value P SV The power can also be specified externally, e.g., with the help of another control unit. The target value of the power P SV is specified and / or determined in particular depending on the position of the accelerator pedal of the motor vehicle and / or with the aid of an assistance system. The target value of the power P SV thus corresponds in particular to a performance desired by the driver of the motor vehicle, taking into account the accelerator pedal position set by the driver.

[0034] The value of the parameter a can - alternatively - be calculated using an intervention power P, which is specified in particular with the aid of the transmission control unit, in addition to the summation just described. Eg This product is then multiplied to the target value of the power P SV then to form and / or calculate the setpoint value of the power P soll In particular, the setpoint power P soll then according to Formula P soll = P SV + P Eg × a is calculated and / or determined. Such an intervention power P Eg can in particular have a fixed value or different values that can be determined with the help of an associated characteristic map.

[0035] For an intermediate value of the quotient q between the different values of the quotient q, a corresponding intermediate value is interpolated from the two respective adjacent values of the parameter a, in particular by means of a linear approach function or a different approach function. According to the representations from Fig. 1 and Fig. 2 is linearly interpolated between the adjacent values of the parameter a, which is determined by the straight sections of the course of the quotient q between the individual times t A , c 1-4 and t E The values of the parameter a for the upshift are shown in the table Fig. 1 negative values, which is symbolized by the asterisk * shown next to the letters w, x, y and z. This allows a reduction of the power P during the switching process. The values of the parameter a for the downshift show, according to the table Fig. 2, on the other hand, have positive values. Thus, an increased power P can be realized during the switching process. Between the values q and a in the table from Fig. 1 and the values q and a from the table Fig. 2 there is a point symmetry with respect to the zero point, ie an equal but negative value of the quotient q is in Fig. 2 compared to Fig. 1 is assigned an equal but positive value of the parameter a. For example, the value q = 0.15 in Fig. 1 the value y* is assigned a negative value and the value q = -0.15 in Fig. 2, the value y is therefore assigned a positive value, which corresponds to a value of y*. However, the aforementioned point symmetry is not required. Values for the parameter a can also be selected for the downshift that differ from the point symmetry for the upshift. This can be useful and expedient, for example, due to different frictional powers realized during the upshift compared to the downshift.

[0036] Setpoints of power P soll and / or values of the parameter a are in a middle time period of the switching process t 2-3 particularly constant. In the tables from Fig. 1 and Fig. 2, two adjacent values of a have the same value, namely the value y* according to Fig. 1 or y according to Fig. 2. The value y* results in the lowest power P during the upshift. The value y results in the highest power P during the downshift.

[0037] The setpoint power P soll at the beginning of the switching process t A essentially corresponds to the target value of the power P soll to the end of the switching process t E . This is achieved in particular by assigning a value a = 0 to the value q = 0 for both the upshift and the downshift. List of reference symbols P Power of the prime mover P soll Setpoint power of the prime mover P SV Target value of the performance P Eg Intervention performance q quotient a Parameter n ist current measured actual speed of the drive machine n aus speed of the drive motor measured at the beginning of the switching process n z Target speed of the drive motor for the end of the gear shift t time t ATime of start of switching process c 1-4 Times during the switching process t E Time of end of switching process

Claims

[1] Method for controlling and / or regulating a drive train of a motor vehicle, wherein the drive train has at least one drive motor and at least one transmission, wherein the drive motor can be effectively coupled and / or is effectively coupled to the transmission, wherein at least two gear stages, each with a fixed transmission ratio, can be set and / or selected by means of the transmission, and wherein during a shifting operation from one of the gear stages to another of the gear stages, at least one power (P) of the drive motor is controlled and / or regulated, characterized by that a quotient (q) is formed from a numerator and a denominator, where the numerator is a difference of a current measured actual speed (n ist ) of the prime mover and a target speed (n z ) of the drive motor for the end of the switching process (t E), where the denominator is the amount of a difference between a value measured at the beginning of the switching process (t A ) measured speed (n aus ) of the prime mover and the target speed (n z ) of the drive motor for the end of the switching process (t E ) is calculated, whereby the power (P) of the drive machine is controlled and / or regulated during the switching process depending on this quotient (q). [2] Method according to claim 1, characterized by that a setpoint of the power (P soll ) of the drive machine is calculated as a function of the quotient (q). [3] Method according to claim 1 or 2, characterized by that the quotient (q) is calculated and / or determined several times in succession during the switching process. [4] Method according to one of the preceding claims, characterized bythat a control variable of the power of the drive machine is calculated as a function of at least one control and / or regulation parameter. [5] Method according to one of the preceding claims, characterized by that the control and / or regulation of the power (P) of the drive machine as a function of the quotient (q) is terminated when the quotient (q) has a value of substantially zero. [6] Method according to one of the preceding claims, characterized by that different values of the quotient (q) are each assigned a value of a parameter (a), whereby the setpoint value of the power (P soll ) is adjusted depending on the parameter (a). [7] Method according to one of the preceding claims, characterized by that the value of the parameter (a) with an intervention power (P Eg ) and this product is added to the target value of the power (P SV) to form and / or calculate the setpoint value of the power (P soll ) is added. [8] Method according to claim 6 or 7, characterized by that if an intermediate value of the quotient (q) exists between the different values of the quotient (q), a corresponding intermediate value is interpolated from the two respective adjacent values of the parameter (a). [9] Method according to one of claims 2 to 8, characterized by that setpoints of power (P soll ) and / or values of the parameter (a) in a middle time period of the switching process (t 2-3 ) are constant. [10] Method according to one of claims 2 to 9, characterized by that the setpoint power (P soll ) at the beginning of the switching process (t A ) essentially corresponds to the setpoint power (P soll ) to the end of the switching process (t E ) corresponds.

Images