System and method for controlling an emergency operation of a transmission for a vehicle

Abstract

A method for controlling an emergency operation of a transmission for a vehicle, comprising: Detecting (S130) an oil temperature of the transmission for the vehicle by a controller (200); Determining (S140), by the controller (200), whether an oil pump has been operated for a predetermined period of time or longer based on the detected temperature; and Limiting (S150) a power of a machine by the controller (200) when the predetermined time has elapsed; wherein the predetermined time period is a time period required for the oil pump to reach a predetermined temperature; wherein a plurality of predetermined time periods are provided for each oil temperature, and the plurality of predetermined time periods of the corresponding temperatures are applied sequentially; and wherein different machine performance values ​​are output based on the plurality of predetermined time periods applied sequentially.

Description

BACKGROUND 1. Technical field

[0001] The present invention relates to a system and method for controlling a limp home mode of a transmission for a vehicle, and more particularly to a system and method for controlling a limp home mode of a transmission for a vehicle capable of controlling the limp home mode based on a temperature of the transmission during a fault in a transmission control unit (GSE). 2. Description of the state of the art

[0002] A transmission for a vehicle, particularly an automatic transmission, includes a transmission control unit (GSE) configured to change a gear ratio based on a driving condition and a load condition of the vehicle, and to sense a condition of the transmission in real time to control the transmission. The transmission is designed to act as an intermediate element connecting the vehicle's power to a drive axle. Consequently, if a gear change is not performed properly, or if the transmission of power is suddenly blocked, the transmission is not under the control of a driver. Consequently, the drivability of the vehicle is impaired, and the safety of passengers may also be compromised.

[0003] Accordingly, according to one prior art, a method has been developed which includes establishing a connection between an electronic shift lever and a GSE configured to control a transmission; controlling a motor to pull an emergency cable coupled to a parking clutch for a park position when the electronic shift lever determines that the GSE is in a faulty state after the connection; determining again by the electronic shift lever whether the GSE is in a faulty state after the emergency cable has been pulled; determining a vehicle speed by the electronic shift lever in response to determining that the GSE is in a faulty state; and allowing a driver to detect that the vehicle speed is greater than a predetermined speed by the electronic shift lever.However, in the prior art described above, no change in hydraulic pressure occurs when a failure occurs in the transmission control unit while the vehicle is running, so safety is not guaranteed.

[0004] From DE 197 55 128 A1, a control system for regulating the temperature of the transmission fluid in an automatic powershift transmission with a torque converter in a motor vehicle with an electronic engine control system having an oil temperature sensor for detecting a transmission temperature correlated with a temperature of the transmission fluid, and a torque reduction device of the control unit of the automatic transmission, which is connected to the electronic engine control system, for continuously reducing the engine output torque when the transmission temperature detected by the oil temperature sensor is above a predetermined temperature value.Preferably, the system arithmetically predicts a rise in transmission temperature above a predetermined temperature value to reduce engine output torque when a temperature rise predicting a transmission temperature above the predetermined temperature value occurs.

[0005] The prior art has been presented merely to provide an understanding of the background of the present invention. It should not be assumed that the prior art is known to one skilled in the art. OVERVIEW

[0006] It is therefore an object of the present invention to provide a method for controlling a limp-home operation of a transmission for a vehicle, which prevents damage to a passenger, an oil pump, and a transmission by operating the transmission at a predetermined gear ratio when the operation of a transmission control unit is stopped, and gradually limits an output of an engine to prevent an overload of the oil pump based on the operation of the transmission.

[0007] The object is achieved by a method for controlling an emergency operation of a transmission for a vehicle having the features of claim 1 and a system for controlling an emergency operation of a transmission for a vehicle having the features of claim 6. Advantageous further developments can be found in the subclaims.

[0008] A method for controlling a limp home mode for a vehicle according to the invention comprises: detecting, by a controller, an oil temperature of the transmission for a vehicle; determining, by the controller, whether an oil pump has been operated for a predetermined period of time or longer based on the detected oil temperature; and limiting an output of an engine when the predetermined period of time has elapsed, wherein the predetermined period of time is a period of time required for the oil pump to reach a predetermined temperature; wherein a plurality of predetermined periods of time are provided for each oil temperature, and the plurality of predetermined periods of time of the corresponding temperatures are sequentially applied; and wherein different engine output values ​​are output based on the plurality of predetermined periods of time that are sequentially applied.

[0009] The method for controlling fail-safe operation of a transmission for a vehicle may further include determining, by a controller, whether a fault has occurred in a transmission control unit for the vehicle.

[0010] In the process of limiting the power output, different engine power values ​​may be output based on the plurality of predetermined time periods applied sequentially. Additionally, the process of limiting the engine power output may be executed to decrease the engine power output values ​​as the plurality of predetermined time periods applied sequentially are gradually decreased. Information regarding the oil temperature of the transmission may be received, a plurality of predetermined time periods required for the oil pump to reach predetermined temperatures may be provided for each oil temperature, and mapping data for outputting predetermined values ​​of the engine power based on the predetermined time periods may be provided.A machine power value may be a value of a predetermined ratio of a normal value of a machine power output (e.g., an output value when no fault occurs). BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The above and other features of the present invention will now be described in detail with reference to exemplary embodiments and their illustration in the accompanying drawings, which are given below for illustrative purposes only and therefore do not limit the present invention. In the drawings: Fig. 1 is an exemplary flowchart of a method for controlling a limp home mode of a transmission for a vehicle according to an exemplary embodiment of the present invention; Fig. 2 is an explanatory diagram showing a relationship between an oil temperature of a transmission and a predetermined time from map data of the method for controlling a limp home operation of a transmission for a vehicle according to an exemplary embodiment of the present invention; and Fig. 3 is an explanatory diagram showing a relationship between a predetermined time and a value of engine power from the map of the transmission fail-safe control method for a vehicle according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0012] It is understood that terms such as "vehicle" or "vehicle-" or similar terms herein include motor vehicles in general, such as passenger cars including sports utility vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including various boats and ships, aircraft and the like, and also include hybrid vehicles, electric vehicles, internal combustion engines, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (for example, fuels not made from petroleum).

[0013] Although the example embodiments use terms in the plural to describe the example operations, it is understood that the example operations may also be performed by one or more modules. Additionally, it is understood that the term "controller" refers to hardware devices including a memory and a processor. The memory is configured to store the modules, and the processor is specifically configured to execute the modules to perform one or more operations described below.

[0014] Furthermore, the control logic of the present invention may be embodied as a non-transitory computer-readable medium on a computer-readable medium comprising executable program instructions that can be executed by a processor, controller / control unit, or the like. Examples of a computer-readable medium include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tape, floppy disk, flash memory, smart cards, and optical storage devices. The computer-readable medium may also be distributed in a network connected to computer systems so that the computer-readable medium can be stored and executed in a distributed manner, for example, through a telemetry server or a Controller Area Network (CAN).

[0015] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a" and "an" and "the" are intended to encompass the plural forms as well, unless the context clearly indicates otherwise. It is further to be understood that terms such as "comprises" and / or "comprising," as used in the specification, describe the presence of the designated features, integers, steps, acts, elements, and / or components, but do not exclude the presence or existence of one or more additional features, integers, steps, acts, elements, components, and / or groups thereof. As used, the term "and / or" includes any and all combinations of one or more of the elements listed in this list.

[0016] Unless expressly stated or obvious from the context, the term "approximately" is considered within a normal range of tolerance, for example, within two standard deviations of the mean. "Approximately" can be understood as 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise obvious from the context, all numerical values ​​should also be considered "approximately."

[0017] Fig. 1 is an exemplary flowchart for a method for controlling a limp-home mode of a transmission for a vehicle according to an exemplary embodiment of the present invention. The method for controlling a limp-home mode of a transmission for a vehicle according to an exemplary embodiment of the present invention may include, by a controller 200, detecting (S130) an oil temperature of the transmission for a vehicle; determining (S140), based on the detected oil temperature, by the controller 200, whether an oil pump has been operated for a set period of time or longer; and limiting (S150) an output of an engine, by the controller 200, if the predetermined time has elapsed. In particular, the method may further include determining (S100) whether a fault has occurred in a transmission control unit for the vehicle after the fault is determined (S100).

[0018] The transmission control unit for the vehicle may be a GSU, and fault determination may be performed with respect to various components. If a pattern of abnormal operation occurs compared to a normal state (e.g., if no fault has been detected), for example, if a shift is not performed despite a set vehicle speed and an accelerator pedal operation value, an abnormal state may be determined, and consequently, it may be determined that a fault has occurred. However, the present invention is not limited to the above-mentioned normal abnormal states, and various examples are possible.

[0019] Meanwhile, in response to the determination that the transmission control unit is in a fault state, a pressure applied to the transmission may be set by the controller (S120) to set a pressure. The set pressure may be tentatively applied multiple times and may be applied to fix the shift state to a specific state to allow the driver to move the vehicle to a safe location if the fault in the transmission control unit occurs while the vehicle is moving. For example, a pressure of approximately 16 bar may be applied. Various components may be considered when determining the pressure to be set. Various examples are possible. The set pressure may be applied by operating an oil pump that provides pressure to the transmission. The oil pump may be an electronic oil pump.

[0020] Additionally, the detection process (S130) may begin after the pressure has been set (S120). However, the detection process (S130) may also begin before the pressure has been set (S120), and a value for an oil temperature within the transmission may be received by a temperature sensor located within the transmission. Specifically, the measurement may be performed by a temperature sensor, and a measured value may be detected and used in the detection process (S130).

[0021] Meanwhile, in the determination process (S140), the predetermined time may be the time required for the oil pump to reach a predetermined temperature (e.g., rise). Specifically, for the determination process (S140), a time required for the oil pump to reach a preset oil temperature in the transmission may be measured, and this may be stored as map data. Additionally, as a result of determining that a failure has occurred in the transmission control unit, a time for failure or a time at which the oil pump provided the set pressure may be measured (S110).The controller may be configured to determine whether the measured time period exceeds the predetermined time period from the detected oil temperature map data, and if the measured time exceeds the predetermined time, the limiting process (S150) may be executed by the controller.

[0022] A plurality of time periods may be specified for each oil temperature, and the plurality of set time periods for each detected oil temperature may be applied sequentially. This is described with reference to Fig. 2. In particular, Fig. 2 is an exemplary diagram illustrating a relationship between a transmission oil temperature and a predetermined time period from the mapping data for the method for controlling limp-home operation in a transmission for a vehicle according to an exemplary embodiment of the present invention, and a plurality of sets of predetermined time periods for each of the plurality of oil temperatures in tabular form. As previously described, the mapping data may be configured to store the plurality of predetermined time periods required for the oil pump to reach a plurality of preset oil temperatures, and when the predetermined time period has elapsed, the limiting process (S150) may be executed.

[0023] A plurality of preset temperature values, which become a reference for the preset time values ​​and at which the oil pump may reach temperatures that cause the oil pump to overheat, may be gradually increasing values, and these may be set experimentally. Meanwhile, in the limitation process (S150), various performance values ​​of the machine can be derived based on the plurality of set times that are applied sequentially. As shown in Fig. 3, which is a graph showing a relationship between a set time and a value of engine power according to the mapping data, specifically, the set time periods may be applied sequentially and increase gradually, and the corresponding set temperatures of the oil pump may also increase over time.

[0024] Furthermore, data for output values ​​of an engine power based on the specified time can be stored as image data, as in Fig. 3, and machine performance values ​​can be decreased as the majority of the set time periods applied successively increase gradually. In the limiting process (S150), control for the machine performance can be output based on machine performance values ​​output from the mapping data.

[0025] The engine power value may be a value of a set ratio of a normal engine power value and may be a value calculated based on a set percentage of an engine power value when the transmission control unit is in a normal state. As in Fig.3, for example, control may be performed by decreasing the engine output value in steps of 90%, 80%, ... of the engine output value in a normal state at a predetermined time A, and outputting an engine output value corresponding to 10% of the engine output value in a normal state at a predetermined time B. The engine output to the transmission may be forcibly decreased so that the driver immediately recognizes an abnormal state of the transmission, and the engine output may be gradually decreased to prevent the oil pump from overheating and to provide the driver with sufficient time to move the vehicle to a safe location.

[0026] According to the method for controlling a limp-home operation of a transmission for a vehicle having the above-described structure, a passenger can detect the abnormal state of the transmission when the vehicle is moving, and driving can be gradually restricted under the control of the driver, thus ensuring the safety of the passengers. In addition, overheating of the oil pump can be prevented, thus avoiding damage to the oil pump. Since the oil temperature of the transmission can be measured to estimate the temperature of the oil pump and control the torque of the engine, a temperature sensor designed to prevent overheating of the oil pump and logic for determining whether a fault occurs in the temperature sensor of the oil pump can be omitted, thus reducing manufacturing costs and improving productivity.

Claims

[1] A method for controlling an emergency operation of a transmission for a vehicle, comprising: Detecting (S130) an oil temperature of the transmission for the vehicle by a controller (200); Determining (S140), by the controller (200), whether an oil pump has been operated for a predetermined period of time or longer based on the detected temperature; and Limiting (S150) a power of a machine by the controller (200) when the predetermined time has elapsed; wherein the predetermined time period is a time period required for the oil pump to reach a predetermined temperature; wherein a plurality of predetermined time periods are provided for each oil temperature, and the plurality of predetermined time periods of the corresponding temperatures are applied sequentially; and wherein different machine performance values ​​are output based on the plurality of predetermined time periods applied sequentially. [2] A method for controlling an emergency operation of a transmission for a vehicle according to claim 1, further comprising: Determining (S100), by the controller (200), whether a fault has occurred in a transmission control unit of the vehicle. [3] A method for controlling an emergency operation of a transmission for a vehicle according to claim 1, further comprising: Reducing the machine power values ​​by the controller (200) when the majority of the predetermined time periods applied consecutively increase in steps. [4] A method for controlling a limp home operation of a transmission for a vehicle according to claim 1, wherein information regarding the oil temperature of the transmission is received, a plurality of predetermined periods of time required for the oil pump to reach predetermined temperatures for each oil temperature are provided, and map data for outputting predetermined engine performance values ​​based on the predetermined periods of time are provided. [5] A method for controlling an emergency operation of a transmission for a vehicle according to claim 1, wherein an engine power value is a ratio of a normal power value of the engine. [6] System for controlling an emergency operation of a transmission for a vehicle, comprising: a memory configured to store program instructions; and a processor configured to execute program instructions, the program instructions, when executed, being configured to: Detecting (S130) a transmission oil temperature for the vehicle; Determining (S140), based on the detected oil temperature, whether an oil pump has been operated for a predetermined period of time or longer; and Limiting (S150) an output power of a machine when the set time period has elapsed; wherein the predetermined time period is a time period required for the oil pump to reach a predetermined temperature; wherein a plurality of predetermined time periods are provided for each oil temperature, and the plurality of predetermined time periods of the corresponding oil temperatures are applied sequentially; and wherein different machine performance values ​​are output based on the plurality of predetermined time periods applied sequentially. [7] A system for controlling an emergency operation of a transmission for a vehicle according to claim 6, wherein the program instructions, when executed, are further adapted to: Determining (S100), after the error detection, whether an error has occurred in a transmission control unit of the vehicle. [8] A system for controlling an emergency operation of a transmission for a vehicle according to claim 9, wherein the program instructions, when executed, are further adapted to: Reduction of machine performance values ​​when the majority of the specified time periods applied consecutively are increased in stages. [9] A non-transitory computer-readable medium having program instructions executed by a controller (200), the computer-readable medium comprising: Program instructions that detect an oil temperature in the transmission for the vehicle; Program instructions that determine whether an oil pump has been operated for a specified period of time or longer based on the detected oil temperature; and Program instructions that limit the performance of a machine when the preset time period has elapsed; wherein the predetermined time period is a time period required for the oil pump to reach a predetermined temperature; wherein a plurality of predetermined time periods are provided for each oil temperature, and the plurality of predetermined time periods of the corresponding oil temperatures are applied sequentially; and wherein different machine performance values ​​are output based on the plurality of predetermined time periods applied sequentially. [10] A non-transitory computer-readable medium according to claim 9, further comprising: Program instructions that determine whether a fault has occurred in a transmission control unit.

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