KR102547829B1 - How to control the vehicle's clutch after the vehicle's coasting mode is terminated - Google Patents

Abstract

The present invention relates to a method for controlling a clutch of a vehicle after the coasting mode of the vehicle ends, and the internal combustion engine speed n _V is, after it is confirmed that the coasting mode of the vehicle ends, the speed of the transmission input shaft ( n _G ) matches. In the case of a method in which the above matching is performed without negative influence on the driving mode, the matching of the internal combustion engine speed (n _V ) to the transmission input shaft speed (n _G ) with the clutch 2 open is the internal combustion engine ( 1), the clutch 2 is engaged when the number of revolutions of the internal combustion engine (n _V ) almost corresponds to the number of revolutions of the transmission input shaft (n _G ).

Description

How to control the vehicle's clutch after the vehicle's coasting mode is terminated

The present invention relates to a method for controlling a clutch of a vehicle after the end of a coasting mode of the vehicle, wherein after it is confirmed that the coasting mode of the vehicle has ended, internal combustion engine revolutions are matched to transmission input shaft revolutions.

A motor vehicle equipped with a drive engine, in particular an internal combustion engine, can be operated much more economically if the internal combustion engine is disconnected from the powertrain, for example when driving downhill or when coasting of the vehicle is desired. This driving situation is referred to as a coasting mode. This coasting mode is set when the clutch provided in the powertrain is disengaged. Additionally, the internal combustion engine can also be shut down.

From DE 10 2012 223 744 A1 a clutch controller is known, in which steps are taken into account for initiating the coasting mode of the motor vehicle and the clutch is disengaged to initiate the coasting mode.

Normally, the coasting mode ends when the rotational speed of the internal combustion engine exceeds the rotational speed of the transmission input shaft so that positive slip prevails on the clutch. In this case, the drive side of the clutch rotates faster than the driven side. After positive slip is formed, further increase in engine speed is prevented through engine torque intervention and the clutch is engaged with the same gradient, or the clutch is engaged with a variable gradient without torque intervention. is concluded with In order to be able to maintain slip on the clutch during a torque intervention that prevents a further increase in the internal combustion engine's speed, the engine torque must be increased together similarly to the clutch torque. In the case of the variant without engine torque intervention, the clutch is likewise engaged with a variable inclination, which causes substantially more slip on the clutch.

The object of the present invention is to specify a method for controlling the clutch of a vehicle after the end of the vehicle's coasting mode, in which matching is carried out without adversely affecting the driving mode.

According to the present invention, the matching of the internal combustion engine rotational speed to the transmission input shaft rotational speed in the clutch open state is performed through torque intervention to the internal combustion engine, and the internal combustion engine rotational speed corresponds to the transmission input shaft rotational speed. When nearly matched, the clutch is resolved through engagement. In this case, since the clutch is operated without slipping, there is an advantage in that wear on the clutch is prevented. With this method, the clutch can also be realized as a dog clutch. Accordingly, clutches that are structurally relatively simpler and thus relatively more economical can be used. Alternatively, the actuator for operating the clutch can be formed very simply and economically, since the actuator only needs to set two states, "open" and "engaged".

Preferably, after reaching a preset revolution difference between the internal combustion engine revolutions and the transmission input shaft revolutions, with the clutch open, the internal combustion engine torque is reduced toward almost zero, and then thereafter clutch is engaged

In one embodiment, the intervention on internal combustion engine torque is preset via a driver's demanded torque, which is preferably increased via a required additional internal combustion engine torque. By inputting the driver's required torque, on the one hand, it is signaled that the coasting mode should be ended, and on the other hand, at the same time, a positive torque is expected at the output of the powertrain.

In one variant, after engaging the clutch, the engine torque is adapted to the driver's requested torque.

In one embodiment, the reduction in internal combustion engine torque is performed prior to reaching transmission input shaft revolutions. As a result, delay times occurring during control of internal combustion engine torque as well as clutch torque are taken into account. Since delay times of the clutch or internal combustion engine are known, the engine delay time can be provided.

In one refinement, the speed difference is determined according to the internal combustion engine speed increase and at an engine delay time determined between a decrease in the internal combustion engine torque and the achievement of gradient equality between the internal combustion engine speed and the transmission input shaft speed. The engine delay time and the internal combustion engine speed increase depend on the actual engine torque of the internal combustion engine and/or the temperature of the internal combustion engine retained by the internal combustion engine before the engine torque is reduced. The engine delay time and internal combustion engine speed rise can simply be determined empirically and stored as a characteristic map dependent on engine temperature and actual engine torque.

Since the internal combustion engine speed increase and the engine delay time may vary differently over time and from one internal combustion engine to another, the internal combustion engine speed increase and the engine delay time are adapted accordingly.

In one variant, the internal combustion engine speed increase is evaluated through slip, which is evaluated after the lapse of the engine delay time. Since slip (difference between engine speed and transmission input shaft speed) is a characteristic variable of the clutch, a corresponding sensor device is provided in each clutch system allowing slip to be evaluated. Thus, evaluation of internal combustion engine speed rise through slip enables a cost-effective method, which is carried out simply by processing with corresponding software.

Preferably, the slip is compared with a slip threshold, and when the slip is below the slip threshold, the internal combustion engine speed increase is reduced after a decrease in engine torque of the internal combustion engine, and when the slip is above the slip threshold, the internal combustion engine is rotated. The number rise is increased after the reduction of the engine torque of the internal combustion engine. The adapted values of the internal combustion engine speed increase after reduction in engine torque of the internal combustion engine are stored in a read-only memory, so that the adapted values are available at any time even after switching off the ignition of the vehicle.

In one embodiment, after a decrease in engine torque of the internal combustion engine, the slope of the internal combustion engine speed is monitored and compared with a time limit until the transmission input shaft speed is reached, the slope reaching the time limit too soon. The engine delay time is reduced, and if the slope reaches the time limit too late, the engine delay time is increased. In this case, the engine delay time is defined as the time required between the engine torque reduction point and the state in which the engine speed reaches the slope of the transmission input shaft speed. For this reason, the slope of the engine speed is monitored after engine torque reduction.

In one refinement, the clutch engagement delay of the clutch actuation system is monitored. Accordingly, the period of the engine delay time corresponds to the engine delay time minus the clutch engagement delay. Engagement of the clutch is requested only after the lapse of the above time. Thus, the goal that the clutch is only engaged in a possible slip-free state is supported.

The present invention allows for a number of embodiments. An embodiment of one of them is described in more detail according to the drawings shown in the drawings section.

1 is a schematic diagram showing a power train of a vehicle.
Figure 2 is a graph showing an embodiment for matching the number of revolutions after the end of the coasting mode.
FIG. 3 is a graph showing an enlarged portion of FIG. 2 .
4 is a graph illustrating a basic principle for adapting an engine delay time and an internal combustion engine speed increase.

1 shows a schematic diagram of a powertrain of a vehicle. The power train comprises an internal combustion engine (1) with its drive shaft connected to a clutch (2). The clutch 2 is connected to the manual transmission 4 via a transmission input shaft 3, the transmission output shaft 5 of which is directed to the drive wheels 6. The manual transmission 4 is operated via a manual transmission module in the form of a selector lever 7 on which a gear selection sensor 8 connected to the clutch control device 9 is fixed. In addition, an engine speed sensor 10 for detecting the speed of the internal combustion engine 1 is connected to the clutch control device 9 . The clutch (2) is actuated by a release system (11), which is actuated by a clutch actuator (12) comprising a clutch control device (9). In addition, the rotational speed of the transmission input shaft 3 is sensed by the transmission input shaft rotational speed sensor 13 .

If the vehicle is in coasting mode, while the internal combustion engine 1 is disengaged from the power train via the clutch 2, the vehicle rolls to save fuel. In one embodiment, the internal combustion engine 1 can also be deactivated during the coasting mode of the vehicle. If the driver of the vehicle indicates that the coasting mode should be ended by actuating the accelerator pedal, which is also connected to the clutch control device 9, positive torque is expected at the output. The clutch engaging characteristic curve in the case of overrun operation is similarly processed.

As shown in FIG. 2 , after the end of the coasting mode, the characteristic curve of the clutch engagement process of the clutch 2 is divided into four phases. In the first phase, the clutch 2 remains open, whereby no clutch torque is generated. In this case, the engine torque of the internal combustion engine 1 is increased without being transmitted through the clutch 2 that is open. The increase in engine torque (M _V ) of the internal combustion engine (1) indicates that the engine speed (n _V ) of the internal combustion engine (10) detected through the engine speed sensor (10) is the transmission input shaft speed sensor (13). It is carried out via the clutch control device 9 until it approximately corresponds to the transmission input shaft revolutions n _G sensed by . To accelerate this process, an increase in internal combustion engine torque (M _V ) may be required, in addition to the driver's requested torque (MF _W ). The first phase ends when the difference between the number of revolutions of the internal combustion engine (n _V ) and the number of revolutions of the transmission input shaft (n _G ) falls below a preset threshold value (N_slip_exit) ( FIG. 3 ).

In the second phase, an intervention is performed on the engine torque (M _V ) of the internal combustion engine, which is now shifted towards zero. This process is also carried out with the clutch 2 open. Subsequent to this, a third phase is started in which the clutch 2 is fully engaged. As a result of non-existent slip due to the reduced engine torque M _V of the internal combustion engine 1 , the clutch 2 can be engaged arbitrarily quickly, which occurs in the third phase. The third phase ends when the clutch 2 is fully engaged or at least significantly transmits the clutch torque Mk.

In the final fourth phase, the reduction intervention on the engine torque M _V of the internal combustion engine 1 is canceled and the engine torque M _V of the internal combustion engine 1 adapts to the level of the driver's requested torque MF _W . do. In this case, the slope of the engine torque of the internal combustion engine 1 plays an important role because the internal combustion engine exclusively takes charge of the output torque in the power train. Here, the slope should mean a rate of change in the number of revolutions of the internal combustion engine 1 or the transmission input shaft 3.

For accurate control of the engine speed n _V of the internal combustion engine 1, the internal combustion engine speed must exactly match the transmission input shaft speed of the transmission input shaft 3, and these two speeds must have the same slope . For this reason, the reduction of the engine torque M _V of the internal combustion engine 1, shown in more detail in FIG. 3, must be carried out. In this case, the required absolute value of the engine torque M _V is proportional to the acceleration of the transmission input shaft 3 .

In the above formula,

는 내연기관의 질량 관성이고,

is the mass inertia of the internal combustion engine,

는 변속기 입력 샤프트의 가속도이다.

is the acceleration of the transmission input shaft.

Since the engine torque M _V reacts to this default with a delay time, the reduction intervention for the engine torque of the internal combustion engine 1 must already be carried out before the transmission input shaft speed of the transmission input shaft 3 is reached. As a criterion for the start of the reduction intervention on the engine torque M _V of the internal combustion engine 1, and thus as the start of the second phase, the internal combustion engine 1 and the transmission input shaft 3, determined by the formula ) is used.

In the above formula,

K_DeltaNEng is the internal combustion engine speed increase after engine torque reduction,

K_EngDelay is an engine delay time between torque reduction and achievement of gradient equilibrium between internal combustion engine speed and transmission input shaft speed.

The increase in rotational speed of the internal combustion engine (K_DeltaNEng) and the engine delay time (K_EngDelay) after the torque reduction is particularly influenced by the actual engine torque (M _V ) just before the torque reduction, the temperature of the internal combustion engine 1, and the like. These values are first determined experimentally and are stored in the software of the control unit 9 as a characteristic map dependent on the internal combustion engine speed increase K_DeltaNEng and the engine delay time K_EngDelay.

Since the parameters may vary over time and from engine to internal combustion engine, the parameters must be adapted. The simplest type of adaptation of the internal combustion engine speed increase (K_DeltaNEng) after torque reduction is to evaluate the slip after the engine delay time (K_EngDelay) has elapsed. If, for example, a slip of 0 revolutions per minute is to be achieved, then the slip is the basis for further consideration as a slip threshold. If the slip actually applied to the clutch 2 is less than the slip threshold value, for example -50 U/min, this means that the value of the internal combustion engine speed increase K_DeltaNEng is too large. This has the same meaning as that the engine torque (M _V ) of the internal combustion engine 1 is reduced too quickly, and as a result, the internal combustion engine speed increase (K_DeltaNEng) after the torque reduction is increased by 20 U/min as shown in FIG. 4A. make it decrease Similarly, if the measured slip exceeds the slip threshold of, for example, 50 U/min, the internal combustion engine speed increase (K_DeltaNEng) increases after the engine torque is reduced (FIG. 4B). If the detected slip is between the two defined threshold limits, no adaptation of the internal combustion engine speed increase (K_DeltaNEng) is executed.

Adaptation of the engine delay time (K_EngDelay) is performed in a corresponding type and manner. In this case, the engine delay time K_EngDelay is defined as a time period that elapses from the engine torque reduction to the state where the internal combustion engine speed reaches the slope of the transmission input shaft speed. Accordingly, the slope of the internal combustion engine speed is monitored after engine torque reduction. If the slope of the internal combustion engine speed reaches the value of the input shaft speed of the transmission input shaft 3 much earlier than after the lapse of the engine delay time K_EngDelay, the engine delay time K_EngDelay is reduced. Otherwise, the engine delay time is increased, which is shown in Figs. 4c and 4d.

For the end of the second phase, in addition to the use of the engine delay time (K_EngDelay), the clutch engagement delay time (K_ClutchDelay) of the clutch actuator 12 may also be included. Accordingly, the period D of the second phase 2 is equal to the following formula.

Engagement of the clutch 2 is required after the elapse of the time period D. In this case, the goal is also to engage the clutch 3 in a slip-free state as much as possible. The less slip during the engagement process of the clutch 2, the more comfortable the process.

1: internal combustion engine
2: Clutch
3: transmission input shaft
4: manual gearbox
5: transmission output shaft
6: driving wheel
7: selector lever
8: gear selection sensor
9: clutch control device
10: engine speed sensor
11: release system
12: Clutch actuator
13: transmission input shaft speed sensor
14: engine shaft
n _V : RPM of internal combustion engine
n _G : Transmission input shaft revolutions
M _V : internal combustion engine torque
Mk: clutch torque
MF _W : driver's required torque

Claims (10)

As a method for controlling a clutch of a vehicle after the end of a coasting mode of the vehicle, after it is confirmed that the coasting mode of the vehicle has ended, an internal combustion engine speed (n _V ) is matched to a transmission input shaft speed (n _G ). , In the vehicle clutch control method,
The matching of the internal combustion engine speed (n _V ) to the transmission input shaft speed (n _G ) with the clutch 2 open is performed through torque intervention in the internal combustion engine 1, and the internal combustion engine speed ( The clutch 2 is engaged when n _V ) corresponds to the transmission input shaft rotation speed n _G ,
With the clutch 2 open, after reaching the preset speed difference between the internal combustion engine speed (n _V ) and the transmission input shaft speed (n _G ), the internal combustion engine torque (M _V ) is zero (0). ) and then the clutch (2) is engaged. delete The method of claim 1, characterized in that the intervention on the internal combustion engine torque (M _V ) is preset through a driver's demanded torque (MF _W ) increased through the additionally requested additional internal combustion engine torque (M _V ). , How to control the clutch of a vehicle. The method according to claim 1, characterized in that, after engaging the clutch (2), the internal combustion engine torque (M _V ) is adapted to the driver's requested torque (MF _W ). The method according to claim 1, characterized in that the reduction of the internal combustion engine torque is performed before reaching the transmission input shaft revolution number (n _G ). According to claim 1, the rotation speed difference is according to the internal combustion engine speed increase (K_DeltaNEng), and the internal combustion engine torque (M _V ) decreases, the internal combustion engine speed (n _V ) and the transmission input shaft speed (n _G ) The engine delay time (K_EngDealy) and the internal combustion engine speed increase (K_DeltaNEng) are again dependent on the engine delay time (K_EngDelay), which is determined between the achievement of gradient equilibrium between the internal combustion engine _and A method for controlling a clutch of a vehicle, characterized in that it depends on at least one of an actual engine torque (M _V ) of an internal combustion engine (1) and a temperature of the internal combustion engine (1). 7. The method according to claim 6, characterized in that the internal combustion engine speed increase (K_DeltaNEng) and engine delay time (K_EngDealy) are adapted. 8. The clutch control method of a vehicle according to claim 7, characterized in that the internal combustion engine speed increase (K_DeltaNEng) is evaluated through a slip evaluated after the lapse of an engine delay time (K_EngDelay). 9. The method according to claim 8, wherein the slip is compared with a slip threshold, and if the slip is less than the slip threshold, the internal combustion engine speed increase (K_DeltaNEng) is reduced after a decrease in engine torque (M _V ) of the internal combustion engine (1), A method for controlling a clutch in a vehicle, characterized in that an increase in internal combustion engine speed (K_DeltaNEng) when slip exceeds a slip threshold value is increased after a decrease in engine torque (M _V ) of the internal combustion engine (1). 7. The method according to claim 6, wherein the slope of the internal combustion engine speed is monitored after a decrease in the engine torque (M _V ) of the internal combustion engine (1) and compared with a time limit until the transmission input shaft speed is reached, wherein the slope is determined over time. When the value of the transmission input shaft speed is reached earlier than the limit value, the engine delay time (K_EngDelay) is reduced, and when the slope reaches the value of the transmission input shaft speed later than the time limit value, the engine delay time (K_EngDelay) is increased. Characterized in, a method for controlling a clutch of a vehicle.

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