KR20010062837A - Method for the coordinated controlling of an engine and a servo-clutch during reduction of torque during gearshift - Google Patents

Abstract

PURPOSE: An integrated control method of a servo clutch and a vehicle engine in reducing torque is provided to change transmission gear ratio promptly and comfortably despite of reduction of torque in changing gears by presetting the desired torque of the engine. CONSTITUTION: An engine(10) of a vehicle and a servo clutch(12) are arranged in a power train of the vehicle, and controlled with a power train control unit(14). The vehicle engine and the servo clutch have an engine output electronic unit and a clutch electronic unit. The desired variable is established in both control units through the power train control unit. The desired gradient to output torque of the clutch is preset in the servo clutch with the power train control unit, and the desired gradient to the output torque of the engine is decided corresponding to the output torque of the clutch. Torque is reduced comfortably and promptly to change transmission gear ratio with setting the desired gradient in advance. Parts are controlled at torque reduction phase in changing speed.

Description

METHOD FOR THE COORDINATED CONTROLLING OF AN ENGINE AND A SERVO-CLUTCH DURING REDUCTION OF TORQUE DURING GEARSHIFT}

The invention relates to a component arranged in a drive train of a vehicle, such as a vehicle engine with an engine output electronic control and a servo clutch with a clutch electronic control, while the torque of the gear stage changes in the transmission of the drive train is reduced. The present invention relates to a method for integrated control.

In the advanced automation of the components arranged in the drive train of the vehicle, it is necessary to integrate control the components in certain situations. Since the vehicle has, for example, an automated manual transmission (ASG), the vehicle engine and clutch have to be adjusted accordingly for the new transmission ratio setting. This type of transmission can be divided into three stages: torque reduction, gear stage change and torque formation. In particular, torque reduction actually causes significant problems. In this way, opening the clutch too quickly undesirably raises the engine speed, while opening the clutch too late unnecessarily extends the shift time. There was no immediate compensation for this type of error control in the prior art and it was best to delay the shifting slightly. The control of the shift progression is substantially achieved through the clutch controller which replaces signals by the shift controller and the engine output controller. Therefore, the influence on engine torque is achieved by clutch control through corresponding engine operation.

Inertia of principle limited control during torque reduction during gear stage change through the method according to the invention for integrated control of the servo clutch and the vehicle engine, using the drive train control with the features of claim 1. Can be overcome. First, the target slope with respect to the clutch output torque is preset in the servo clutch. The target slope is then determined for the engine output torque corresponding to the target slope of the clutch output torque. By presetting the target slopes, the torque reduction required for shift ratio change can be executed quickly and comfortably.

The target slope of the clutch output torque for the torque reduction phase is well determined according to the selected operating factors such as shift-ID, driving situation, driver type or shift situation. The duration of the torque reduction phase can be determined by the same operating factor. Overall, it has proven beneficial if the slope of the clutch torque is achieved as a hyperbloical tangent function.

According to the method according to the invention, the slopes of the engine torque and the clutch torque are matched. However, it has proved beneficial to consider the switching operation between the target engine output torque and the actual engine output torque. Also in the drive train control, an engine model is provided which provides the evaluation engine torque as an output variable. The torque is an input variable for clutch control.

It is also advantageous for the determination of the target engine output torque to take into account operating variables such as shift-ID, driving situation, driver type and shift situation, for example. Such measures can be implemented, for example, via corresponding characteristic curves.

Other preferred configurations of the invention are described in the features described in the dependent claims.

1 is a schematic graph of the slope of a target clutch output torque.

2 is a schematic block diagram of a drive train controller for determining target variables for a vehicle engine and a vehicle clutch.

3 is a schematic block diagram for determining a target engine output torque.

<Explanation of symbols for the main parts of the drawings>

10: engine

12: clutch

14: drive train control unit

16: counting block

md _{ka, soll} (t): clutch output torque

md _{ma, soll} (t): engine output torque

md _{ma, soll} : target engine output torque

KL _{md, ma} (t '): characteristic curve

Hereinafter, the present invention will be described in detail with reference to the drawings.

In Fig. 2, the components substantially necessary for controlling the vehicle engine 10 and the servo clutch 12 using the drive train control unit are shown. The vehicle engine 10 and the servo clutch 12 are disposed in a drive train of the vehicle and have an engine output electronic controller engine-SG and a clutch electronic controller clutch-SG, the corresponding target variables being communicated via the drive train controller 14. It is set in both control parts. This type of control on the components 10, 12 is carried out in accordance with the invention at a certain phase, ie at the torque reduction phase during the gear stage change in the automatic transmission.

The torque reduction (first phase) phase has the following characteristics.

The start (time ta) is derived through a new gear stage request, for example by a suitable algorithm for gear stage selection. Determination of the inevitable step change is well known and therefore not described in detail herein.

During the torque reduction phase the clutch 12 is opened and the engine torque md _ma is set appropriately. The end of the gear stage propagation phase is characterized in that no rotational torque is transmitted from the clutch 12 anymore. The variable md _ka of the clutch output torque has a value of 0 Nm. When the gear stage progression to the time point te is reached at the end of the first phase, the first condition becomes as follows.

md _ka (t _e ) = 0 Nm (I)

The condition must be met so that the previous gear stage can be released with less force.

In addition, the clutch at the first phase end of the first gear stage progression must be wide open to no longer transmit torque. In other words, the maximum torque m _{dk, max that} can be transmitted from the clutch 12 has a value of 0 Nm as well. The torque m _{dk, max} is set through the control of the clutch actuator, and the torque md _ka actually transmitted from the clutch 12 is equal to or smaller than the maximum torque m _{dk, max that} can be transmitted. The second condition is as follows.

md _{k, max} (t _e ) = 0 Nm (II)

The above condition means that no force connection is generated between the clutch input shaft and the clutch output shaft. This allows the transmission to adapt the rotational speed of the clutch input shaft to the synchronous rotational speed of the new gear.

The engine 10 is controlled from the time point t _a in a manner described in detail below. From one time point t _b ≥ t _a , the clutch 12 is controlled such that the moment m _{dk, max} is reduced and the time interval t _b ≤ t ≤ t _e is indicated as "clutch release".

In particular, in shifting to a step in which the speed ratio is high, other conditions for controlling the engine 10 and the clutch 12 are achieved during clutch release. Thereby, the clutch input rotation speed n _ke is always the same as the clutch output rotation speed n _ka . At this time, the third condition is as follows.

n _ke (t) = n _ka (t), t _b ≤ t ≤ t _e (III)

In shifting to a step of high speed ratio, the engine speed corresponding to the new gear stage is smaller than the actual engine speed. As a result, it is not meaningful that the engine speed and the clutch input speed n _ke are equally increased during the clutch release, which only disturbs the driver. On the other hand, during the clutch release, the clutch input speed n _ke is not less than the clutch output speed n _ka because the positive clutch output torque is no longer transmitted at the next slip that occurs.

The target slope mdka with respect to the clutch output torque in the time interval t _a , t _e is determined during torque reduction. An exemplary slope of the torque m _{dka, soll} (t) is shown in FIG. 1. As described above, from the time point ta, the torque md _{ma, soll} is transmitted to the engine 10 via the drive train 14, and the target output moment md _{k, soll} for controlling the clutch release to the clutch. It is set in advance. The target slope of the clutch output torque md _{ka, soll} (t) can be determined through the function F (τ) according to the following equation.

md _{ka, soll} (t) = md _{red , startF} (τ)

Where τ is τ = (t-tb) / t _red (VI)

t _red = t _e -t _b (VIII)

T _red represents the clutch release duration, and torque (md _{red, start} ) represents the clutch output moment at the beginning of the clutch release. At the end of the clutch release progression, that is, at time t _e , τ = 0. When the speed ratio is fixed and the running resistance is set in advance, the vehicle acceleration is proportional to the transmitted clutch output torque md _ka . Since the running resistance can be kept almost constant during the clutch release duration t _red , the clutch output torque slope md _ka determines the vehicle acceleration slope upon clutch release.

The function F (τ) and the duration t _red can be advantageously determined according to some possible variable. These variables include, for example, a shift-ID representing an evaluation variable for the transmission ratio change of the transmission at the time of switching between predetermined gear stages, or for example ramp and stop and stop & go and Driving conditions in the same predetermined operating mode may be considered. Also, for example, from a driver's type that prefers either a sporting or economical driving method, or a shift situation (e.g. from a shift characteristic curve) for the determination of the function F (τ) and duration t _red . Gear stage selection) may also be considered.

The function F (?) Can be achieved, in particular, as a hyperbolic tangent according to the following equation, as explained.

F (τ) = 1/2 (tanh (-α · τ + β) + 1) (IX)

Where α and β can be used freely and represent factors that allow individual adaptation to the operating system.

It is clearly shown in the drawing according to FIG. 2 that the target engine output torque md _{ma, soll} has to be determined for the integrated control of the engine 10 and the clutch 12. This is described in detail in calculation block 16. The torque md _ma is on the one hand at the input in the engine model 18 and on the other hand is used as an input variable for the engine-SG which is the engine output control.

Engine model 18 transmits an estimated engine output torque md _{ma, est} representing the input variable for clutch-SG, the clutch control.

md _{k, soll} = md _{ma, est} (X)

The estimated engine output torque md _{ma, est} is determined at actual time by the engine model 18 under consideration of the dead time T _t and the transfer function φ. The clutch 12 is set so that the clutch can always transmit the torque md _{k, soll} at maximum. Therefore, the actual clutch output torque md _ka is md _ma , but at most md _{k, soll} .

The target engine output torque md _{ma, soll} is determined in calculation block 16, and is executed as follows.

As described above, at a time interval t _a , t _e for the torque reduction phase, the slope of the engine output torque md _ma (t) corresponds to the clutch output torque md _{ka, soll} (t). The slope of the engine output torque md _{ma, soll} (t) is preset. This establishes the following relationship.

md _ma (t) = md _{ka, soll} (t) (XI)

The transfer function φ and dead time T _t are carried out according to the following equation in order to consider the switching operation, and the required engine output torque is set dynamically by the engine using the switching operation.

md _ma (t) = φ {md _{ma, soll} (tT _t )} (XII)

Using equations (XI) and (XIII) the setpoint for engine output torque

φ {md _{ma, soll} (tT _t )} = md _{ka, soll} (t) (XIII)

It depends on. The following formula holds according to the inversion of the transfer function φ.

md _{ma, soll} (tT _t ) = φ ^-1 {md _{ka, soll} (t)} (XIV)

Recognizing the switching operation of the engine 10 from a predetermined target slope with respect to the clutch output torque md _{ka, soll} (t), the target engine output md _{ma, soll} (t to satisfy the conditions described above during the torque reduction phase The slope for)) can be determined. A target slope for md _{ma, soll} (t) is generated for a predetermined slope (md _{ka, soll} (t)).

Normalization of the target slope with respect to torque md _{ma, soll} is achieved according to the characteristic curve KLi _{md, ma} (see FIG. 3). The input variable of the characteristic curve is the time t 'elapsed from the beginning of the first phase of the shifting process.

t '= t-t _a (XV)

Viewpoint by the corresponding control of the engine 10

t _a = t _b -T _t (XVI)

Starts from. The determination of the target engine output torque md _{ma, soll} is achieved by the following equation.

md _{ma, soll} = KLi _{md, ma} (t ') md md _{red, start} (XVII)

The characteristic curve KLi _{md, ma} may depend on certain operating variables such as shift-ID, driving situation, driver type and shift situation.

According to the present invention, a comfortable and fast shift ratio change is achieved even if the target engine torque is preset so that the torque is reduced during the gear stage change.

Claims (8)

In a method for integrally controlling parts arranged in a drive train of a vehicle, such as a vehicle engine with an engine output electronic control and a servo clutch with a clutch electronic control, while the torque is reduced when the gear stage is changed in the transmission of the drive train. In By the drive train control unit 14 (a) The target slope for the clutch output torque (md _{ka, soll} (t)) is preset in the servo clutch 12, (b) correspondingly, the target slope with respect to the engine output torque md _{ma, soll} (t) is determined in the clutch output torque md _{ka, soll} (t). The method according to claim 1, wherein the target slope of the clutch output torque (md _{ka, soll} (t)) with respect to the torque reduction phase depends on the selected operating factor such as, for example, shift-ID, driving situation, driver type or shift situation. Which method is determined. Method according to any of the preceding claims, characterized in that the duration of the torque reduction phase (t _red ) is determined in accordance with the selected operating factor such as shift-ID, driving situation, driver type or shift situation. The method of claim 1 wherein the slope of the clutch output torque (md _{ka, soll} (t)) is established as a hyperbolic tangent function. An engine model 18 is provided in the drive train 14 which provides the estimated engine output torque md _{ma, est} as an output variable, thereby providing a target engine output torque md _{ma, soll.} ) And the actual engine output torque (md _ma ) is considered. 6. Method according to claim 5, characterized in that the estimated engine output torque (md _{ma, est} ) is an input variable to the clutch control (clutch-SG). Method according to any of the preceding claims, characterized in that the target engine output torque (md _{ma, soll} ) is determined in accordance with the selected operating factor such as shift-ID, driving situation, driver type or shift situation. . A target engine output torque (md _{ma, soll} ) is determined from the characteristic curve (KL _{md, ma} (t '), and the input variable of the characteristic curve is the time elapsed from the beginning of the torque reduction. ).