Method for controlling a clutch for vehicles

Abstract

A method for controlling a clutch (CL1, CL2) for a vehicle, comprising: determining an increased torque offset of an internal combustion engine by a controller (C) through an input calculation using compensation for an incorrect torque of the internal combustion engine when the torque of the internal combustion engine rises to a reference torque or above in the idle state of the internal combustion engine; prior to determining the increased torque offset, assessing whether the conditions for the input calculation are met by the idle state of the internal combustion engine, a start-up holding time of the internal combustion engine, a disengaged state of the clutch (CL1, CL2), and a coolant temperature; and controlling the clutch (CL1, CL2) based on the determined torque offset of the internal combustion engine by the controller (C).

Description

BACKGROUND OF THE INVENTIONField of the invention

[0001] The present invention relates to a method for controlling a clutch for vehicles, in which an incorrect torque of the internal combustion engine is compensated and the clutch is controlled based on the compensated torque of the internal combustion engine in order to improve the precision of the control. Description of related technology

[0002] An automated manual transmission is a system in which a transmission is automatically controlled based on a manual transmission mechanism, and such a transmission transmits the torque of the internal combustion engine by means of a dry clutch, unlike an automatic transmission which uses a torque converter and a multi-plate clutch.

[0003] However, the dry clutch has the characteristic that the torque transmitted by the clutch varies greatly depending on various factors such as the tolerances of the constituent elements, the degree of wear of the elements depending on the durability, the thermal deformation of the elements caused by high temperatures, the change in the friction coefficient of a disc, etc., and therefore it is difficult to evaluate the torque transmitted to the dry clutch during driving.

[0004] Failure to detect the change in transmitted torque during clutch control may result in excessive clutch slippage or shock loads, and therefore an algorithm for evaluating dry clutch torque characteristics in real time is required.

[0005] Accordingly, the torque transmission characteristics of a clutch were evaluated in a conventional manner using the clutch control system to establish a torque-stroke curve (TS curve), i.e., a torque transmission characteristic curve of a dry clutch. Here, the TS curve of the dry clutch is a curve in which the torque transmission characteristics of the dry clutch are recorded as a function of the strokes of a clutch actuator to create a database.

[0006] The input torque to a transmission is the torque from the internal combustion engine, which is transferred to the wheels via the clutch. To ensure stability during gearshift control, a stable internal combustion engine torque input to the transmission is also important.

[0007] Information regarding the engine torque actually input from the engine can only be accurately calculated if engine drag torque modeling and the load of an air conditioner, etc., are accurately considered. However, such factors cannot be accurately reflected in the engine torque. Furthermore, if an engine control unit (ECU) transmits incorrect engine torque information to a transmission control unit (TCU), starting the vehicle may be impossible, or the engine may overspeed during gear shifting if the accuracy of the engine torque cannot be ensured.

[0008] The information disclosed in this Background of the Invention section is provided only to facilitate understanding of the general background of the invention and is not intended as an acknowledgement or any form of indication that it represents prior art known to those skilled in the art. SHORT SUMMARY

[0009] Various aspects of the present invention are directed to providing a method for controlling a clutch for vehicles in which an incorrect torque of the internal combustion engine is compensated and the clutch is controlled based on the compensated torque of the internal combustion engine to improve the precision of the control.

[0010] According to various aspects of the present invention, a method for controlling a clutch for vehicles may include determining, by a controller, the increased torque offset of the internal combustion engine when the torque of the internal combustion engine is increased to a reference torque or above in the idle state of the internal combustion engine, and controlling the clutch by the controller based on the determined torque offset of the internal combustion engine.

[0011] Before the determination, the method may further include judging whether or not the conditions for the input calculation are met by the engine idle state, the engine cranking hold time, the clutch release state, and the cooling water temperature.

[0012] During the determination, the torque offset of the internal combustion engine can be determined using a function that represents relationships to the torque of the internal combustion engine, the angular acceleration of the internal combustion engine, the rotational inertia of the internal combustion engine and the clutch torques.

[0013] After the determination, the method may further include judging whether or not at least one of an absolute value of the speed change of the internal combustion engine and an absolute value of the torque change of the internal combustion engine is smaller than a reference value.

[0014] After the determination, the method may further include judging whether or not the calculation time of the torque offset of the internal combustion engine meets the specified time period or is longer when the torque of the internal combustion engine increases to the reference torque or above.

[0015] During control, the clutch torque can be controlled based on an average value of the determined torque offset of the internal combustion engine during starting and gear changing.

[0016] During control, the torque values ​​transmitted by the clutch can be learned based on an average value of the determined torque offset of the combustion engine.

[0017] It is understood that the term "vehicle" or "vehicular" or other similar terms used herein generally refer to motor vehicles, such as passenger cars, including sports utility vehicles (SUVs), buses, trucks, various commercial vehicles, personal watercraft including various boats and ships, aircraft, and the like, and also includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles (chargeable from a wall outlet), hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As used herein, a hybrid vehicle is a vehicle with two or more power sources, e.g., vehicles with both gasoline and electric power.

[0018] The methods and apparatus of the present invention have still other features and advantages which will be apparent from or pointed out in more detail in the accompanying drawings, which are hereby incorporated by reference, and the following detailed description, which together explain certain principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Fig. 1 is a schematic view of an overall system of a DCT vehicle to which the present invention can be applied.

[0020] Fig. 2 is a flowchart of a method for controlling a clutch according to an embodiment of the present invention.

[0021] Fig. 3 is a graph illustrating the concept of a method for controlling a clutch in accordance with an embodiment of the present invention.

[0022] It should be understood that the accompanying drawings are not necessarily to scale, presenting a somewhat simplified representation of the various preferred features illustrative of the principles of the invention. The specific design features of the present invention disclosed herein, including, for example, particular dimensions, orientations, locations, and shapes, will be determined in part by the particular intended application and the environmental conditions at the site of use. DETAILED DESCRIPTION

[0023] Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings, which are described below. While the invention(s) will be described in conjunction with exemplary embodiments, it is to be understood that the present description is not intended to limit the invention(s) to these embodiments. Rather, the invention(s) are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments within the spirit and scope of the invention as defined by the appended claims.

[0024] A method for controlling a clutch for vehicles according to various embodiments of the present invention may include calculating (operation S20) and controlling (operation S50).

[0025] The procedure is based on the Fig. 2 and Fig. 3. If, during the calculation (operation S20), the torque of the internal combustion engine increases to the reference torque or above in the idle state of the internal combustion engine, a controller C can calculate the increased torque offset of the internal combustion engine.

[0026] For example, in the idling state of the engine in a shift position P or a shift position N, a change between the minimum and maximum values ​​of the engine torque and a change between the minimum and maximum values ​​of the engine speed are measured in real time. When the engine torque increases beyond the minimum engine torque due to the load of an air conditioning control, etc., the controller C can detect such an increase and calculate the engine torque offset by calculating the offset amount of the increased engine torque.

[0027] Thereafter, during control (operation S50), the controller C can control the clutch based on the calculated torque offset of the internal combustion engine.

[0028] That is, when incorrect engine torque information is transmitted due to the load of the air conditioner, etc. in the engine idling state, the engine torque offset is calculated by compensating the engine torque, and the clutch control is executed based on the assumption that the calculated engine torque offset is a transmission input torque.

[0029] Therefore, the clutch control is carried out based on an accurate real torque of the combustion engine, which improves the precision of the clutch control and thus ensures more stable gear changes and driving behavior.

[0030] The method according to various embodiments of the present invention may further include the first judgment as to whether or not the conditions for the input calculation (operation S20) are satisfied by the idling state of the engine, the engine cranking holding time, the released state of the clutch, and the cooling water temperature (operation S10).

[0031] The calculation (operation S20) can be executed when, for example, the current engine speed A is RPM or below, the target engine idling speed B is RPM or below, the holding time after engine start-up is C seconds or more, both a clutch for the odd-speed transmission and a clutch for the even-speed transmission are released, and the cooling water temperature is D°C or more.

[0032] That is, as exemplified in Fig. 1, various embodiments of the present invention can be applied to a vehicle in which a dual clutch transmission (DCT) is installed, and for ease of understanding, of the two clutches in the DCT, a clutch for the odd-numbered transmission and a clutch for the even-numbered transmission are denoted by CL1 and CL2, respectively; a clutch actuator for the odd-numbered transmission and a clutch actuator for the even-numbered transmission for actuating the respective clutch are denoted by CLA1 and CLA2, respectively; and an input shaft for the odd-numbered transmission and an input shaft for the even-numbered transmission are denoted by INPUT1 and INPUT2, respectively.

[0033] As in Fig.2, in the calculation (operation S20) of the present invention, the torque offset of the internal combustion engine can be calculated by a function representing relationships with the torque of the internal combustion engine, the angular acceleration of the internal combustion engine, the rotational inertia of the internal combustion engine, and the clutch torques. Preferably, the torque offset of the internal combustion engine can be calculated by the following equation.

[0034] Engine torque offset (Te_offset) = Te – Je dNe / dt + (Tc_odd + Tc_even), where Te: engine torque, Je: engine rotational inertia, dNe / dt: engine angular acceleration, Tc_odd: gearbox clutch torque for odd gears, and Tc_even: gearbox clutch torque for even gears.

[0035] Furthermore, the method according to various embodiments of the present invention may include the second judgment as to whether or not the absolute value of the speed change of the internal combustion engine or the absolute value of the torque change of the internal combustion engine is smaller than the reference value (operation S30) after the calculation (operation S20).

[0036] For example, if the absolute value of the speed change of the internal combustion engine is smaller than E RPM or the absolute value of the torque change of the internal combustion engine is smaller than F Nm, control (operation S50) can be executed.

[0037] Furthermore, if the conditions for the first judgment (operation S10) are met in the second judgment (operation S30), control (operation S50) can be executed.

[0038] That is, if the idling state of the engine is kept constant after calculating the torque offset of the engine, the clutch control can be executed based on the torque offset of the engine, thereby improving the reliability of the clutch control.

[0039] Furthermore, according to various embodiments of the present invention, the method may include a third judgment as to whether or not a calculation time of the torque offset of the internal combustion engine has been maintained within the predetermined time or exceeded when the torque of the internal combustion engine increases to the reference torque or above (operation S40).

[0040] For example, if the calculation of the torque offset of the internal combustion engine takes G seconds or longer, control (operation S50) can be executed.

[0041] That is, if the torque offset of the internal combustion engine is utilized only when the increase of the torque of the internal combustion engine continues for a predetermined time or longer, except in the case where the increase of the torque of the internal combustion engine occurs temporarily in the idling state of the internal combustion engine, the reliability of the clutch control is improved.

[0042] Furthermore, during control (operation S50), the clutch torque can be started based on the calculated torque offset of the internal combustion engine during starting and gear shifting.

[0043] That is, when a vehicle is started or a gear shift occurs, the engine power is transmitted to a clutch when the clutch is engaged, and the compensated engine torque offset is used as the transmission input torque, so that the gear shift or vehicle start is controlled based on the engine torque offset. Therefore, the gear shift / start control is performed based on the actual engine torque, thereby improving the precision of clutch control.

[0044] Furthermore, during control (operation S50), the transmitted clutch torque characteristics can be learned based on the calculated torque offset of the internal combustion engine.

[0045] That is, when learning the dry clutch characteristics, the clutch characteristics are learned based on the engine torque (engine torque offset) input from a real engine, and thus more accurate clutch transmission torque characteristics can be learned based on the accurate engine torque, and the precision of dry clutch control can be improved.

[0046] As apparent from the above description, in a method for controlling a clutch for vehicles according to various embodiments of the present invention, the engine torque offset is calculated by compensating the engine torque even when incorrect engine torque information is transmitted in the engine idling state, and the clutch control is performed under the assumption that the calculated engine torque offset is the transmission input torque. Therefore, the clutch control is performed based on the accurate real engine torque, thereby improving the precision of the clutch control and thus ensuring more stable gear shifting and drivability.

[0047] The above descriptions of specific embodiments of the present invention are provided for purposes of example and description. They are not intended to be exhaustive or to limit the invention to the forms disclosed, and obviously numerous modifications and variations are possible in light of the above teachings. The embodiments were chosen and described in order to explain certain principles of the invention and their practical application to enable others skilled in the art to make and utilize various embodiments of the present invention, as well as various alternatives and modifications. It is intended that the scope of the invention be defined by the appended claims and their equivalents.

Claims

[1] A method for controlling a clutch for a vehicle, comprising: Determining the increased torque offset of the internal combustion engine by a controller when the torque of the internal combustion engine increases to a reference torque or above in the idle state of the internal combustion engine; and Controlling the clutch based on the determined torque offset of the combustion engine by the controller. [2] The method of claim 1, further comprising, prior to determining the increased torque offset of the internal combustion engine: Judge whether the conditions for the input calculation are met or not by the idling state of the internal combustion engine, the cranking holding time of the internal combustion engine, the released state of the clutch and the cooling water temperature. [3] The method of claim 1, wherein in determining the increased torque offset of the internal combustion engine, the torque offset of the internal combustion engine is determined by a function representing relationships with the torque of the internal combustion engine, the angular acceleration of the internal combustion engine, the rotational inertia of the internal combustion engine and the clutch torques. [4] The method of claim 1, further comprising, after determining the increased torque offset of the internal combustion engine: Assess whether at least either the absolute value of the speed change of the internal combustion engine or the absolute value of the torque change of the internal combustion engine is smaller than a reference value or not. [5] The method of claim 1, further comprising, after determining the increased torque offset of the internal combustion engine: Judge whether the calculation time of the engine torque offset meets the specified time or is longer when the engine torque increases to the reference torque or above. [6] The method according to claim 1, wherein the clutch control controls the clutch torque based on the average value of the torque offset of the internal combustion engine determined during starting and gear changing. [7] The method according to claim 1, wherein in the clutch control, the clutch transmission torque characteristics are learned based on the average value of the determined torque offset of the internal combustion engine.

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