DE102013114958B4 - Start-up control for a vehicle with a dual clutch transmission - Google Patents

Abstract

A vehicle (10), comprising:an engine (12);an engine control module (30) in connection with the engine (12), the engine control module (30) providing an actual torque value (TE) of the engine (12). ; and a dual clutch transmission (DCT) assembly (14) having first and second input clutches (C1, C2), first and second gear sets (24, 124) selectively connected to the respective first and second input clutches (C1, C2). engine (12), and a transmission control module (20) connected to the DCT assembly (14) and the engine control module (30) and having a calibrated torque-to-position table (60);wherein the transmission control module (20) is designed to: receive (102) a starting request (Th%) of the vehicle (10); receive the actual torque value (TE) of the engine (12) from the engine control module (30) ( 106);determine (104);an inertia torque value (Iα) as the product of an acceleration (α) and an inertia (I) of the engine (12);a clutch torque (TCALC) for a specific one of the first and second input clutches (C1, C2) as a function of the actual torque value (TE) of the engine (12) and the inertia torque value (Iα); calculate (108) a difference (Δ) between the calculated clutch torque (TCALC) and a commanded clutch torque (Tcc) ; and to provide (112, 114) control of a position (P) of the particular input clutch (C1, C2) using the difference (Δ) as a feedback term, wherein the transmission control module (20) is designed to control the position (P) at least in part by extracting the clutch position (P) from the torque-to-position table (60) and transmitting the clutch position signal to the specific input clutch (C1, C2), the transmission control module (20) being configured to provide the torque-to-position Modify position table (60) so that less clutch torque in the torque-to-position table corresponds to a given engagement position of the particular input clutch (C1, C2) when the calculated clutch torque (TCALC) exceeds the commanded clutch torque (Tcc) ( 110), and so that more clutch torque in the torque-to-position table corresponds to the given engagement position when the calculated clutch torque (TCALC) is less than the commanded clutch torque (Tcc) (110);Adjusting the torque-to-position Table (60), where the amount of adjustment is limited by limits (112, 114).

Description

This disclosure relates to the starting control of a vehicle with a dual clutch transmission.

Dual clutch transmissions combine certain features of manual and automatic transmissions. In a dual clutch transmission or DCT with odd and even gear sets, one of a pair of input clutches is engaged to engage any of the odd gear sets. Likewise, the other input clutch is engaged to engage any of the even gear sets. An on-board transmission controller predicts the next gear to be selected using available control inputs such as engine acceleration and braking levels, and then commands engagement of the next gear at the start of the upcoming shift. Compared to a conventional transmission, a DCT can deliver quicker gear changes, typically with improved shift control and increased power.

The two available input clutches in a wet DCT are cooled and lubricated by transmission fluid that is circulated via an engine-driven or auxiliary fluid pump. In a dry DCT (dDCT), the various gear sets within a DCT gearbox are cooled and lubricated in the same manner, while the two input clutches remain dry. As a result, a dDCT may experience a greater amount of temperature-related performance variation relative to a wet DCT.

The US 2008 / 0 207 393 A1 discloses a vehicle comprising: an engine; an engine control module in communication with the engine, the engine control module providing an actual torque value of the engine; and an input clutch, a gear set selectively connected to the engine via the respective first and second input clutches, and a transmission control module connected to the input clutch and the engine control module and having a calibrated torque-to-position table. The transmission control module is configured to receive a drive request of the vehicle; receive the actual engine torque value from the engine control module; determine an inertia torque value as the product of an acceleration and an inertia of the engine; calculate a clutch torque for the input clutch as a function of the actual engine torque value and the inertia torque value; calculate a difference between the calculated clutch torque and the commanded clutch torque; and provide control of a position of the input clutch using the difference as a feedback term. The transmission control module is configured to provide position control at least in part by extracting a clutch position from a torque-to-position table and transmitting the clutch position signal to the input clutch.

It is the object of the present invention to achieve smooth, consistent behavior when starting a vehicle equipped with a dual clutch transmission assembly.

This task is achieved by a vehicle with the features of claim 1.

Advantageous embodiments are specified in the dependent claims.

• 1 ist eine schematische Darstellung eines Fahrzeugs, das ein Doppelkupplungsgetriebe (DCT) mit einer Kupplungsposition aufweist, die während des Anfahrens des Fahrzeugs unter Verwendung eines Anfahrsteuerungsverfahrens geregelt wird, wie es hierin beschrieben ist.
• 2 ist ein Satz von Zeitdiagrammen, die die sich ändernden Amplituden von verschiedenen Fahrzeugleistungsvermögenswerten beschreiben, wobei die Zeit auf der horizontalen Achse aufgetragen ist und die Amplitude auf der vertikalen Achse aufgetragen ist.
• 3 ist ein Zeitdiagramm eines Beispielkupplungspositions-Regelungssignals für eine Eingangskupplung des in 1 gezeigten DCT, wobei die Zeit auf der horizontalen Achse aufgetragen ist und die Amplitude auf der vertikalen Achse aufgetragen ist.
• 4 ist ein Beispiel-Drehmoment-zu-Position-Modell, das mit dem Fahrzeug von 1 verwendbar ist, wobei das befohlene Kupplungsdrehmoment auf der horizontalen Achse aufgetragen ist und die Kupplungsposition auf der vertikalen Achse aufgetragen ist.
• 5 ist ein Flussdiagramm, das eine Beispielausführungsform eines Fahrzeuganfahrregelungsverfahrens für das in 1 gezeigte Fahrzeug oder für jedes andere Fahrzeug, das eine nasse oder eine trockene DCT als Teil seines Antriebsstrangs aufweist, beschreibt.

The invention is described below using the drawings as an example:

• 1 is a schematic illustration of a vehicle having a dual clutch transmission (DCT) with a clutch position controlled during vehicle launch using a launch control method as described herein.
• 2 is a set of time charts that describe the changing amplitudes of various vehicle performance values, with time plotted on the horizontal axis and amplitude plotted on the vertical axis.
• 3 is a timing diagram of an example clutch position control signal for an input clutch of the in 1 DCT shown, with time plotted on the horizontal axis and amplitude plotted on the vertical axis.
• 4 is an example torque-to-position model used with the vehicle from 1 can be used, with the commanded clutch torque plotted on the horizontal axis and the clutch position plotted on the vertical axis.
• 5 is a flowchart illustrating an example embodiment of a vehicle launch control method for the in 1 vehicle shown or for any other vehicle that has a having wet or dry DCT as part of its powertrain.

Referring to the drawings, in which like reference numerals refer to like components throughout the various figures, in 1 a vehicle 10 shown schematically. The vehicle 10 includes an internal combustion engine 12 and a dual clutch transmission (DCT) assembly 14, with the engine (E) 12. The speed of the engine 12 is responsive to a received gas request (arrow Th%), eg a force or a percentage of a Movement of an accelerator pedal 11 or other suitable device that indicates a relative level of requested engine torque. Such a force/distance can be detected via a sensor (not shown) in a conventional manner. In response to receiving the throttle request (arrow Th%), the engine 12 generates input torque (arrow T _l ) into the DCT assembly 14 and delivers the input torque (arrow T _l ) to the DCT assembly 14 via a rotatable drive member 15.

As understood in the art, a DCT is an automated, manual-type transmission that includes a gearbox 13 with two independently operated input clutches, ie, the respective one in 1 shown first and second input clutches C1 and C2. Although to simplify the presentation 1 omitted, each input clutch C1 and C2 may include a center plate containing any number of friction disks, friction plates, or other suitable friction materials. The input clutches C1 and C2 of the DCT assembly 14 may be lubricated/wet, or they may be dry, both designs described above. That is, fluid (arrow F) may be circulated by an engine-driven fluid pump 31 to the input clutches C1, C2 in a wet DCT embodiment, or the fluid (arrow F) may be circulated only to the gear box 13 in a dry DCT embodiment. Associated electronic and hydraulic clutch controls (not shown) ultimately regulate shifting operation and starting of the vehicle in response to instructions from various onboard controllers, as discussed in detail below.

In the example DCT assembly 14 from 1 The first input clutch C1 controls all odd-numbered gear sets 24 (GSo) of the DCT assembly 14, for example the first, third, fifth and seventh gears in an example 7-speed transmission, while the second input clutch C2 controls each even-numbered gear set 124 (GS _E ) controls, for example, the second, fourth and sixth in the same example 7-speed transmission. Within each of the gear sets 24, 124 additional clutches, e.g. B. hydraulic, piston-operated, rotating or braking clutches can be engaged or disengaged as required to produce the desired gear state. The reverse gear state may be part of the odd gear set 24 and controlled via the first input clutch C1. Using this type of gear arrangement, the DCT assembly 14 can be quickly shifted through its available range of gears without completely interrupting the power flow from the engine 12.

The controllers of the in 1 Vehicle 10 shown includes at least a transmission control module (TCM) 20 and an engine control module (ECM) 30. As described below with reference to FIG 2-4 executed, the TCM 20 operates in conjunction with the ECM 30 during startup of the vehicle 10 to thereby provide engine acceleration-based position control of any actuators of the particular input clutch, e.g. B. clutch piston to initiate. As a rule, input clutch C1 would be used for starting in 1st gear, although starting in other gears is not excluded and therefore input clutch C2 could be controlled in the same way. For a dry DCT, the present launch control approach can help address the fundamental fluctuations to improve launch quality. Although such fluctuation is typically more prevalent in a dry DCT due to the lack of cooling at the friction interfaces of the input clutches, starting a vehicle with a wet DCT may also benefit from the present invention.

In the example vehicle 10 of 1 The DCT assembly 14 also includes an output shaft 21 connected to a set of drive wheels (not shown). The output shaft 21 ultimately transmits output torque (arrow To) to the drive wheels to drive the vehicle 10. The DCT assembly 14 may include a first shaft 25 connected to the first input clutch C1, a second shaft 27 connected to the second input clutch C2, and respective even and odd gear sets 24, 124 (GSo, GS _E ). , which is arranged within the gearbox 13, both by circulating a transmission fluid from a sump 35 via an engine-driven main pump 31, e.g. B. can be cooled and lubricated via a pump shaft 37, or alternatively via an auxiliary pump (not shown).

Within the DCT assembly 14, the first shaft 25 is connected to and drives only the odd gear sets 24 (GSo). The second shaft 27 is connected to and drives only the straight gear sets 124 (GSE), which include a reverse gear set. The DCT assembly 14 further includes upper and lower main shafts 17 and 19, respectively, connected to final drive (F/D) gear sets 34, 134. The final drive gear sets 34 and 134 are in turn connected to the output shaft 21 of the DCT assembly 14 and are designed to provide any required final drive reduction.

With respect to the controllers of the vehicle 10, the TCM 20 and the ECM 30 may be configured as microprocessor-based devices having components such as processors 22, 32, memories 23, 33, tangible, non-transitory computer-readable media, such as Includes, but is not necessarily limited to, read-only memory (ROM), optical memory, solid-state flash memory, and the like, as well as random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), flash memory, etc., and a circuit comprising a high speed clock, analog-to-digital (A/D) circuitry, digital-to-analog (D/A) circuitry, a digital signal processor or DSP, transceivers 26, 36 and the necessary input/output (E /A) devices and other signal conditioning and / or buffer circuitry includes, but is not limited to.

The TCM 20 and ECM 30 are programmed to perform the required steps of the launch control procedure, an example of which is at 100 in 5 is shown, wherein the TCM 20 in particular provides a proportional, integral, derivative (PID)-based position control of the operation of a particular input clutch C1 and C2 during the entire duration of a start-up of the vehicle 10. As part of the present traction control method, the ECM 30 may generate various regulation or control values, which include an engine speed request (arrow N _ER ) for the control of the engine 12 and an engine acceleration value (arrow Iα), the latter of which goes to the TCM 20 is transmitted from the TCM 20 for use in a calculation of what is hereinafter referred to as a calculated clutch torque. Ultimately, the TCM 20 uses the engine acceleration value (arrow Iα), specifically the variance between engine torque and the calculated clutch torque, in maintaining position control of the input clutch C1 or C2 and outputs a position control signal (arrow P _X ) to the particular input clutch C1 or C2 to thereby control the position of the particular input clutch C1 or C2 in the manner described below.

With reference to 2 a set of lines describes 50 different performance characteristics during a start-up of the in 1 shown vehicle 10. In each of the lines, the signal amplitude (A) is plotted on the vertical axis and the time (t) is plotted on the horizontal axis. At time t ₀ , a driver of the vehicle 10 requests a start by depressing the accelerator pedal 11. In response to the increased gas request, a corresponding engine speed request is generated by the ECM 30, for example, where the engine speed request is proportional to the gas request (line Th% of 1 ).

When the engine speed request is transmitted from the ECM 30 to the engine 12, the various actuators of the engine 12 are controlled by the ECM 30 as necessary to provide a calibrated rate of engine acceleration. The actual torque of the engine (line T _E ) increases, with most of this torque initially doing the work of increasing the speed of the engine (line N _E ). As understood in the art, the actuators of the engine can z. B. spark plugs and / or cylinders of the engine 12, whereby the ECM 30 controls the speed of the engine (line N _E ) by controlling the spark / ignition, the number of active cylinders, etc.

wobei α die gemessene oder berechnete Beschleunigung der Kraftmaschine 12 ist und die anderen Faktoren oben beschrieben sind. Jede Differenz zwischen dem befohlenen Kupplungsdrehmoment (Tcc) von dem TCM 20 und dem berechneten Kupplungsdrehmoment (T_CALC), das wie oben dargelegt abgeleitet wird, wird verwendet, um eine Regelkorrektur der Kupplungsposition der bestimmten Eingangskupplung C1 oder C2 der in 1 dargestellten DCT-Baugruppe 14 durchzuführen, wobei eine mögliche Einstellung an einer TTP-Tabelle aufgezeichnet ist oder für das TCM 20 zugänglich ist.Some of the actual engine torque (T _E ) from engine 12 is necessary to overcome the inertia (l) of engine 12, particularly when starting. Moment of inertia of the engine (l) is used in the position control of the various engine actuators. More specifically, a calculated torque (T _CALC ) may be derived by the TCM 20 as follows: $$T_{CALC}=T_E-I\alpha$$

where α is the measured or calculated acceleration of the engine 12 and the other factors are described above. Any difference between the commanded clutch torque (Tcc) from the TCM 20 and the calculated clutch torque (T _CALC ) derived as set forth above is used to provide a control correction to the clutch position of the particular input clutch C1 or C2 of FIG 1 DCT module 14 shown to be carried out, with a possible ual setting is recorded in a TTP table or is accessible to the TCM 20.

In 2 When the accelerator pedal 11 is depressed, the speed of the engine (N _E ) increases sharply before stabilizing at approximately t ₁ . Engine torque (T _E ) mainly does the work of increasing the engine speed (N _E ) in this initial interval t ₀ - t ₁ . In this start-up stage, a high engine torque (T _E ) minus a large calculated inertia torque value (Iα) results in low calculated torque (T _CALC ). If the engine speed (N _E ) is a calibrated target, e.g. B. reached at about t ₁ , the engine torque (T _E ) may drop to slow the engine 12 or there may be sufficient clutch torque (Tcc) to stop the acceleration of the engine 12. The calculated torque (T _CALC ) increases to meet the commanded clutch torque (Tcc). A deviation (Δ) of the calculated clutch torque (T _CALC ) from the commanded clutch torque (Tcc) causes the TCM 20 to initiate clutch position control with the goal of bringing T _CALC and Tcc into agreement.

The commanded clutch torque (Tcc) may be provided as a calibration value from the TCM 20, for example extracted from a lookup table or from a torque model recorded in memory 23. The TCM 20 thus monitors the actual torque of the engine (line T _E ) and the moment of inertia of the engine (line Iα) to determine exactly how much load is on the input clutch C1 or C2 of the DCT assembly 14 1 acts during the approach and then sets the position signal (line P _X from 3 ) as needed over time.

With reference to 3 the clutch position signal (line Px) is from the TCM 20 1 generated and sent to the special input clutch C1 or C2 1 , which is used to regulate the starting of the vehicle, is transmitted. As used herein, an "augmented" clutch position signal is any position signal or position command that results in movement of a clutch applying piston or other actuator in an engagement direction of the input clutch C1 or C2, and thus is a signal resulting in a Increase in clutch torque. Likewise, a "reduced" clutch position signal results in movement of a clutch engagement piston or other actuator in the release direction, and is thus a signal that results in reduced clutch torque.

In an example control action in which a calculated clutch torque exceeds the commanded clutch torque from the TCM 20, the clutch position signal (line P _X ) may be modified downward to form line P _X ^- . A control action in which the calculated clutch torque is less than the commanded clutch torque may cause the clutch position signal (line P _x ) to be adjusted upward to form line Px ⁺ . At about t ₂ the 2 and 3 the particular input clutch C1 or C2 reaches synchronous speed and the vehicle 10 is fully moved, typically in first gear.

A setting of the clutch position signal (line Px) from 3 may result in the automatic modification of a recorded torque-to-position (TTP) table 60, an example of which is shown in 4 is shown, with torque (T) plotted on the horizontal axis and position (P) plotted on the vertical axis. The embodiment of 4 is a simple three-position TTP model stored in memory 23 of the in 1 TCM 20 shown can be recorded. Such a table may be used by the TCM 20 to determine exactly how much torque (T) to command for a given clutch position (P), and vice versa. The TTP table 60 may include a calibrated minimum torque T ₁ , a calibrated intermediate torque T ₂ , and a calibrated maximum torque T ₃ , illustrated together as a TTP trace 62 . Each torque value corresponds to a minimum clutch position, a medium level clutch position or a maximum clutch position P ₁ , P ₂ or P ₃ . Thus, as part of a possible regulatory action, the TCM 20 may modify or adjust the TTP table 60 over time, eg, upward in the direction of arrow 65 as shown, to form an adjusted TTP trace 64 that can be recorded for use at the next switching.

With reference to 5 begins an example method 100 for regulating a start-up of the in 1 shown vehicle 10 at step 102, wherein the ECM 30 of 1 receives a gas signal (arrow Th%) indicating that a driver of the vehicle 10 has depressed the accelerator pedal 11 with sufficient force to thereby request the vehicle 10 to start. The method 100 proceeds to step 104 when the gas signal (arrow Th%) has been detected.

Step 104 involves deriving the clutch torque (T _CALC ) as explained above, such as via the product of the known inertia (l) and the measured or calculated acceleration (α) of the engine 12. The inertia (l) may be a calibrated value recorded in the memory 23 of the TCM 20. The acceleration (α) may be determined using any suitable approach, for example, by calculating the rate of change of a measured engine speed signal or by direct measurement. The calculated clutch torque (T _CALC ) is recorded and the method 100 then proceeds to step 108.

In step 106, the actual torque of the engine (line T _E from 2 ) determined. Such a value may, in a particular embodiment, be available from a torque model recorded in memory 33 of ECM 30. Thus, for any given speed point, the torque output from the engine 12 is known and reported to the TCM 20, such as via a Controller Area Network (CAN) bus.

At step 108, the TCM 20 next determines whether a commanded clutch torque, ie, line Tcc of 2 , is equal to the calculated clutch torque (T _CALC ) of step 104, or at least within a small calibrated range of the calculated clutch torque (T _CALC ). If this is the case, there is no adjustment to the clutch position signal (line P _X of 3 ) is required, and method 100 repeats step 102. Steps 102 through 108 may continue in a loop until an exit condition signals a shift to steady state control, which typically indicates completion of startup once the input clutch reaches synchronous speed. If the commanded clutch torque (line Tcc of 2 ) is not equal to the calculated clutch torque (T _CALC ), the method 100 proceeds to step 110 instead.

Step 110 includes determining, via the TCM 20, whether the commanded clutch torque (Tcc) exceeds the calculated clutch torque (T _CALC ) of step 104. If so, the method 100 proceeds to step 112. Otherwise, the method 100 proceeds to step 114.

At step 112, the TCM 20 may receive the clutch position signal (line Px from 3 ) down, i.e. reduce the clutch position signal by a calibrated amount so that less clutch torque is applied for that position. Step 112 may include customizing a TTP table, such as the example TTP table 60 of 4 , entail. The amount of adjustment may be limited by deadbands or other appropriate limits to avoid overadjustment of the TTP model. For example, the position may be reduced by no more than 0.5 mm in each control loop in one possible approach, or by less than 2 mm in another embodiment. The method 100 returns after setting the position signal (line Px from 2 ) back to step 102.

At step 114, the TCM 20 provides the clutch position signal (line Px of 3 ) up, i.e. increases the clutch position signal by a calibrated amount so that more clutch torque is applied to that position. As with step 112, step 114 may involve modifying/adjusting the TTP table 60 of 4 by a small calibrated amount. The method 100 returns after setting the clutch position signal (line Px from 2 ) or the TTP table 60 back to step 102.

Using the method 100 set forth above, the TCM 20 may 1 mix an engine speed request by requesting spark retard or throttle control from the ECM 30 to match the acceleration rate of the vehicle 10. In other words, the calculated torque described above is transmitted to the ECM 30 as a feedforward control term. In this way, the feel of starting is improved relative to traditional approaches. The TCM 20 ensures that command clutch torque of the input clutch C1 or C2 corresponds as closely as possible to the calculated clutch torque via PID-based clutch position control throughout startup. The present approach will help prevent the TCM 20 from commanding clutch torque to too high a level, which could cause undesirable engine pull-down. Such an approach can detect any change in the actual TTP characteristics of a given DCT over time, for example the DCT assembly 14 of 1 , handle better while still allowing maximum output torque through start-up as the engine's torque capacity increases.

Claims (3)

Vehicle (10) comprising: an engine (12); an engine control module (30) in communication with the engine (12), the engine control module (30) providing an actual torque value (T _E ) of the engine (12); and a dual clutch transmission (DCT) assembly (14) having first and second input clutches (C1, C2), a first and second gear set (24, 124) which are selectively connected to the engine (12) via the respective first and second input clutches (C1, C2), and a transmission control module (20) which is connected to the DCT assembly (14) and the engine control module (30) in communication and having a calibrated torque-to-position table (60); wherein the transmission control module (20) is configured to: receive (102) a start request (Th%) of the vehicle (10); receive (106) the actual torque value (T _E ) of the engine (12) from the engine control module (30); to determine (104) an inertia torque value (Iα) as the product of an acceleration (α) and an inertia (I) of the engine (12); calculate a clutch torque (T _CALC ) for a particular one of the first and second input clutches (C1, C2) as a function of the actual torque value (T _E ) of the engine (12) and the moment of inertia value (Iα); calculate (108) a difference (Δ) between the calculated clutch torque (T _CALC ) and a commanded clutch torque (Tcc); and to provide (112, 114) control of a position (P) of the particular input clutch (C1, C2) using the difference (Δ) as a feedback term, the transmission control module (20) being configured to control the position (P). at least in part by extracting the clutch position (P) from the torque-to-position table (60) and transmitting the clutch position signal to the specific input clutch (C1, C2), the transmission control module (20) being configured to provide the torque-to-position -Modify position table (60) so that less clutch torque in the torque-to-position table corresponds to a given engagement position of the particular input clutch (C1, C2) when the calculated clutch torque (T _CALC ) is the commanded clutch torque (Tcc) exceeds (110), and so that more clutch torque in the torque-to-position table corresponds to the given engagement position when the calculated clutch torque (T _CALC ) is less than the commanded clutch torque (Tcc) (110); Adjust the torque-to-position table (60), with the amount of adjustment limited by limits (112, 114). Vehicle after Claim 1 , wherein the engine control module (30) includes a recorded torque model and is configured to extract the actual torque value of the engine from the recorded torque model. Vehicle after Claim 1 wherein the transmission control module (20) is configured to detect when the particular input clutch (C1, C2) reaches a synchronous speed and to transition to steady state control of the particular input clutch in the first gear when the particular input clutch (C1, C2) the synchronous speed is reached.

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