KR20240085345A - Electric vehicle transmission control system and method - Google Patents

Abstract

A transmission control system and method for an electric vehicle are disclosed.
According to an embodiment of the present invention, a transmission control system for an electric vehicle includes a motor that generates driving torque, a transmission that performs multi-stage shifting using a dog clutch in a binding relationship with a one-way clutch that transmits forward power of the motor, An EPB (Electronic Parking Brake) that operates the brake electronically, a motor controller that controls the driving torque of the motor according to the driver's accelerator pedal (Accelerator Position Sensor, APS) signal, and the transmission according to a torque command based on the APS value Controls multi-stage shifting, but when the dog clutch release fails in a stopped state, the EPB is operated, an estimate of the stress generated between the sleeve and the gear tooth of the dog clutch is calculated, and a primary torque command based on the stress estimate is applied to the motor to drive in the forward direction. It includes a vehicle controller that returns the sleeve in a state in which stress is relieved by driving.

Description

Electric vehicle transmission control system and method {ELECTRIC VEHICLE TRANSMISSION CONTROL SYSTEM AND METHOD}

The present invention relates to a transmission control system and method for an electric vehicle, and more specifically, to a transmission control system and method for an electric vehicle for fail-safe when a dog clutch mounted on a transmission cannot be released.

In the field of transmission generally applied to automobiles, a clutch is a device used to switch power transmission. For example, in the case of an automatic transmission, the system is implemented by combining several clutches, and power is transmitted according to each gear ratio according to the operation and release of the combined clutch. At this time, the axes connected to each clutch are rotating at a rotation speed multiplied by the transmission input speed, output speed, or gear ratio. That is, the clutch performs speed synchronization, power transmission, and power transmission release through coupling and disengagement of axes with different rotation speeds or the same rotation speed.

Recently, in the field of transmission, dog clutches have been actively used to improve power transmission efficiency. For example, transmissions applied to electric vehicles (xEV) are a representative example.

Figure 8 shows a dog clutch applied to a conventional electric vehicle transmission and a situation in which the clutch cannot be released.

Referring to Figure 8(A), the dog clutch is a mechanism that transmits power through teeth engagement at both ends and has a simple structure such as a hub, sleeve, gear teeth, and sleeve drive motor.

The dog clutch does not use hydraulic pressure and has the advantage of high transmission efficiency as there is no friction element for speed synchronization at both ends of the clutch. On the other hand, since there is no fluid buffering effect and no speed synchronization mechanism, speed synchronization and sleeve position control through precise control are required.

However, if precise control of the dog clutch is not performed, shock may occur due to contact without cushioning between each tooth, and there is a problem of causing a feeling of jamming or abnormality when engaging or disengaging for forward power transmission due to the engagement method.

Referring to Figure 8(B), as a conventional transmission structure for an electric vehicle, a dog clutch is used to improve transmission transmission efficiency as a separate component for using regenerative braking in a gear shift using a one-way clutch. This is a configuration in which the one-way clutch operates as a forward power transmission element and the dog clutch operates as a reverse power transmission element. Therefore, in gear shifts using a one-way clutch, the dog clutch is pre-engaged or engaged during driving to prepare for regenerative braking.

However, in the case of this structure, in a forward power transmission situation, displacement of the dog clutch element in a restraint relationship with the one-way clutch may occur due to backlash of the one-way clutch. In this case, the dog clutch probabilistically changes to a power transmission state rather than a deposited state depending on the relative positions of the elements, causing a problem in which release of the dog clutch becomes impossible due to friction between elements (i.e., contact between gear teeth and sleeve teeth). .

In addition, when the dog clutch integrates a friction clutch or parking function, if the dog clutch cannot be released, other integrated functions become unusable, so there is a problem that driving the vehicle becomes impossible.

Meanwhile, in response to this problem of not being able to release the dog clutch, a method of attempting to move the sleeve by operating the sleeve drive motor at maximum torque can be considered. However, in this case, there is a disadvantage that it cannot be released due to the judder phenomenon occurring or the torque limit where the friction between the sleeve and teeth is greater than that of the sleeve drive motor.

In addition, in terms of design, methods of modifying the shape of the teeth, adjusting the number of teeth, and excluding the connection relationship between parts related to dog clutch displacement can be considered. However, this method has the disadvantage of greatly limiting its application due to the interaction between design elements and NVH (Noise, Vibration, Harshness) performance, and packaging limitations.

The matters described in this background art section have been prepared to enhance understanding of the background of the invention, and may include matters that are not prior art already known to those skilled in the art in the field to which this technology belongs.

An embodiment of the present invention is a transmission control system for an electric vehicle that releases the dog clutch through Fail Safe control when the dog clutch cannot be released due to displacement due to backlash of a one-way clutch applied to the transmission of an electric vehicle, and the transmission control system for the electric vehicle. The purpose is to provide a method.

Another object of the present invention is to provide a transmission control system and method for an electric vehicle that manages the degree of deterioration by accumulating the frequency of dog clutch disengagement, warns the driver, and enters the vehicle safety mode to induce preventive maintenance. Do this.

According to one aspect of the present invention, a transmission control system for an electric vehicle includes a motor that generates driving torque; a transmission that performs multi-stage shifting using a dog clutch in a restrained relationship with a one-way clutch that transmits forward power of the motor; EPB (Electronic Parking Brake), which operates the brakes electronically; A motor controller that controls the driving torque of the motor according to the driver's accelerator pedal (Accelerator Position Sensor, APS) signal; and controlling multi-stage shifting of the transmission according to a torque command based on the APS value, but calculating an estimate of the stress generated between the sleeve and gear teeth of the dog clutch after operating the EPB when the dog clutch is failed to be released in a stopped state, and the stress It includes a vehicle controller that applies a first torque command based on an estimate to the motor and performs a first fail-safe control to return the sleeve in a state in which stress is relieved by forward driving.

In addition, the transmission includes an input shaft (IN) that receives power from the motor; An output shaft (OUT) installed parallel to the input shaft (IN) and transmitting power through a multi-stage transmission gear; and a drive shaft installed parallel to the output shaft (OUT) and transmitting power transmitted through a terminal gear to a drive wheel, wherein the multi-stage transmission gear is external to each other along the longitudinal direction of the input shaft (IN) and the output shaft (OUT). It may include a first gear and a second gear installed to do so.

In addition, the dog clutch may transmit forward power together with the one-way clutch by coupling the sleeve with the gear teeth, and return to the hub side after releasing the coupling for regenerative braking to transmit reverse power.

Additionally, in order to calculate the stress estimate, the vehicle controller may collect the forward torque value generated by the motor while immediately performing engagement control of the dog clutch and store it in a memory.

In addition, the vehicle controller multiplies the forward torque value by a compensation factor for the individual torque performance of the sleeve actuator, the inclination state of the vehicle, and the stationary acceleration, and adds a fault diagnosis compensation value for determining deformation of the clutch element to determine the stress. Estimates can be calculated.

Additionally, if the clutch release through the first fail-safe control fails, the vehicle controller may perform the second fail-safe control by applying a second torque command based on the maximum forward torque to the motor.

In addition, if the clutch release through the secondary fail-safe control fails, a failure warning of the clutch component may be displayed through a display device while the EPB operation is maintained, and shift gear fixation and motor torque generation may be limited.

In addition, when the vehicle controller fails to release the clutch through the first fail-safe control, the number of release failures is increased by 1 and cumulatively stored in the non-volatile memory, and if the accumulated number of release failures exceeds the set reference value, Inspection warnings and motor torque output can be limited.

Meanwhile, according to one aspect of the present invention, a transmission control method for an electric vehicle that performs multi-stage shifting including a dog clutch in a restrained relationship with a one-way clutch that transmits forward power of the motor includes disengaging the dog clutch in a stopped state. In case of failure, initiating primary fail-safe control and applying the brake via EPB; calculating an estimate of stress generated between the sleeve and gear teeth of the dog clutch; Attempting to release the sleeve while relieving stress through forward driving by applying the primary torque command based on the stress estimate to the motor; and if the clutch release through the first fail-safe control fails, performing a second fail-safe control of attempting to release the sleeve by applying a second torque command based on a forward maximum torque that is stronger than the first torque command. Includes.

In addition, calculating the stress estimate may include extracting from a memory a forward torque value stored while performing engagement control of the dog clutch immediately before; And calculating the stress estimate by multiplying the forward torque value by a compensation factor for the individual torque performance of the sleeve actuator, the inclination state of the vehicle, and the stationary acceleration, and then adding a fault diagnosis compensation value for determining deformation of the clutch element. do..

In addition, the step of attempting to release the sleeve may include monitoring whether a creep torque is input by an APS signal by the driver or by setting to the system while releasing the sleeve; and when the APS signal or creep torque is input, releasing the brake operation through the EPB and canceling the first fail-safe attempt.

In addition, if the clutch release through the first fail-safe control fails, the step of increasing the number of release failures by 1 and accumulatively storing it in the non-volatile memory.

In addition, when the number of release failures accumulated in the memory exceeds a set standard value, the method may include warning inspection of clutch components and limiting the amount of motor torque output.

In addition, when it is confirmed that the secondary release has failed as a result of completing the secondary fail-safe control, a failure warning of the clutch component is displayed through a display device while maintaining the brake operation of the EPB, and the motor torque generation is limited. It may include entering a vehicle safety mode.

According to an embodiment of the present invention, when the dog clutch cannot be released due to displacement due to backlash of the one-way clutch applied to the transmission, it is controlled to be released through fail-safe control, which has the effect of solving the phenomenon of component damage and impossibility of driving.

In addition, by accumulating the number and frequency of dog clutch failures to be released, the degree of deterioration and failure of parts is predicted, thereby warning drivers and inducing safe driving, which has the effect of preventing accidents due to drive system failure.

In addition, by improving the phenomenon of dog clutch release inability through software (S/W) that performs clutch alignment control without adding or changing separate hardware (H/W), one-way clutch and dog clutch can be locked in electric vehicles without additional cost. There is an effect of being able to actively apply the installed transmission.

Figure 1 schematically shows the configuration of a transmission control system for an electric vehicle according to an embodiment of the present invention.
Figure 2 shows the connection and restraint relationship between elements of a one-way clutch and a dog clutch applied to a transmission according to an embodiment of the present invention.
Figure 3 shows an engaged state of a dog clutch applied to a transmission according to an embodiment of the present invention.
Figure 4 shows a phenomenon in which the dog clutch cannot be released due to backlash of the one-way clutch according to an embodiment of the present invention.
Figure 5 shows a fail-safe control state and control map for dog clutch release according to an embodiment of the present invention.
6 and 7 are flowcharts schematically showing a transmission control method for an electric vehicle according to an embodiment of the present invention.

Below, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, singular forms are intended to also include plural forms, unless the context clearly indicates otherwise. The terms “comprise” and/or “comprising”, when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not include other It will also be understood that this does not exclude the presence or addition of one or more of features, integers, steps, operations, elements, components and/or groups thereof. As used herein, the term “and/or” includes any one or all combinations of the associated listed items.

Throughout the specification, terms such as first, second, A, B, (a), (b), etc. may be used to describe various components, but the components should not be limited by the terms. These terms are only used to distinguish the component from other components, and the nature, sequence, or order of the component is not limited by the term.

Throughout the specification, vehicle or automobile refers to an electric vehicle (Xev).

Throughout the specification, when a component is referred to as being 'connected' or 'connected' to another component, it may be directly connected or connected to the other component, but other components may exist in the middle. It must be understood that it may be possible. On the other hand, when a component is said to be 'directly connected' or 'directly connected' to another component, it should be understood that there are no other components in between.

Throughout the specification, the terminology used is for the purpose of describing specific embodiments only and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

Additionally, it is understood that one or more of the methods or aspects thereof below may be implemented by at least one or more controllers. The term “controller” may refer to a hardware device that includes memory and a processor. The memory is configured to store program instructions, and the processor is specifically programmed to execute the program instructions to perform one or more processes described in more detail below. A controller may control the operation of units, modules, components, devices, or the like, as described herein. It is also understood that the methods below can be performed by an apparatus that includes a controller along with one or more other components, as will be appreciated by those skilled in the art.

Now, the transmission control system and method for an electric vehicle according to an embodiment of the present invention will be described in detail with reference to the drawings.

Figure 1 schematically shows the configuration of a transmission control system for an electric vehicle according to an embodiment of the present invention.

Figure 2 shows the connection and restraint relationship between elements of a one-way clutch and a dog clutch applied to a transmission according to an embodiment of the present invention.

Figure 3 shows an engaged state of a dog clutch applied to a transmission according to an embodiment of the present invention.

1 to 3, the transmission control system 100 of an electric vehicle (xEV) according to an embodiment of the present invention includes a driving information detector 110 that detects driving information from various sensors according to the driver's driving intention, and a vehicle A motor 120 that generates a driving torque, a transmission 130 that performs multi-stage shifting using a one-way clutch 131, a dog clutch 132, and a friction clutch 133, and a speed sensor that measures the speed of the transmission output side. (135), a motor controller (Motor Control Unit, MCU) 140 that controls the driving torque of the motor 120 according to the accelerator pedal sensor (Accelerator Position Sensor, APS) signal collected as the driving information, and the APS It includes a vehicle controller 150 that controls multi-stage shifting of the transmission 130 according to a torque command based on the value. Here, the control status of the electronic parking brake (EPB) 160 and the transmission 130 that operate the brake (BK) in conjunction with the vehicle controller 150 for fail-safe control. It may further include a display device 170 that displays a warning according to. The display device 170 is an in-vehicle cluster or is configured as a navigation (AVN) system.

The driving information detector 110 detects driving information necessary for transmission control from various sensors and controllers according to the operation of the vehicle and transmits it to the motor controller 140 and/or the vehicle controller 150. For example, the driving information detector 110 detects at least one of vehicle speed, APS signal, brake pedal sensor (BPS) signal, motor torque, wheel speed, shift gear, vehicle inclination state, and stationary acceleration according to the operation of the electric vehicle. The driving information included can be detected. Additionally, the driving information detector 110 can collect the transmission output side speed measured by the speed sensor 135 in real time and transmit it to the vehicle controller 150.

The motor 120 generates driving torque for driving the electric vehicle.

The transmission 130 includes a multi-stage transmission gear (G) for an electric vehicle and heterogeneous clutches 131, 132, and 133 for dynamic transmission thereof.

The speed sensor 135 detects the rotational speed (RPM) of the output side of the transmission 130 and generates a signal.

The vehicle control unit (VCU) 150 is a computing system that controls the overall operation of the vehicle, including the transmission control function, and stores at least one program and data for the control in the non-volatile memory 151. . However, the vehicle controller 150 is not limited to this and can be implemented as a normal transmission control unit (TCU).

The vehicle controller 150 transmits a torque command considering the driver's APS value, vehicle stop state, and driving conditions to the motor controller 140 based on driving information collected in real time.

The motor controller 140 drives the motor 120 according to the torque command received from the vehicle controller 150.

The motor controller 140 may perform motor torque increase control and motor torque regeneration control and transmit the resulting actual motor torque and actual speed information to the vehicle controller 150.

The vehicle controller 150 controls the operation of the transmission 130 and the heterogeneous clutches 131, 132, and 133 applied thereto in consideration of motor torque and actual speed information. At this time, the vehicle controller 150 may control the moving position of the sleeve 1322 by applying a current command to the sleeve actuator 134 to operate the dog clutch 132.

The transmission 130 includes an input shaft (IN) that receives power from the motor 120, an output shaft (OUT) installed parallel to the input shaft (IN) and transmitting power through a multi-stage transmission gear (G), and an output shaft (OUT) ) and includes a drive shaft (DA) that is installed in parallel and transmits power transmitted through the terminal gear (G3) to the drive wheel (W).

Here, the multi-stage transmission gear (G) includes a first-stage gear (G1) and a second-stage gear (G2) installed to circumscribe each other along the longitudinal direction of the input shaft (IN) and the output shaft (OUT).

In addition, the drive shaft (DA) can transmit the power transmitted through the output shaft (OUT) and the terminal gear (G3) installed to circumscribe each other to the drive wheels (W) on both sides through the differential (D). The driving wheel W may be at least one of the front and rear wheels of an electric vehicle.

The transmission 130 is applied to the first gear (G1) of the output shaft (OUT) and has a one-way clutch 131 that operates as a forward power transmission element and is connected to the rear end of the one-way clutch 131 as a reverse power transmission element. Includes an operating dog clutch 132.

In addition, the transmission 130 includes a friction clutch 133 that is applied to the second gear G2 of the output shaft OUT and synchronizes the speed of both ends and prevents shift shock through mechanical slip.

The friction clutch 133 may be constructed using dry or wet friction material.

The dog clutch 132 is connected to a hub 1321 connected to the output shaft OUT and a gear tooth 1323 connected to the one-way clutch 131 of the first gear G1, between the hub 1321 and the gear tooth 1323. It includes a sleeve 1322 that moves linearly and selectively couples.

The sleeve 1322 is moved by an electrically operated sleeve actuator 134. The sleeve actuator 134 has individual torque performance set according to the applied product.

The vehicle controller 150 may control the moving position of the sleeve 1322 by applying a current command to the sleeve actuator 134 to operate the dog clutch 132.

For example, the vehicle controller 150 may move the sleeve 1322 horizontally through the sleeve actuator 134 to control the engaging, disengaging, and depositing states.

For example, as shown in Figure 3, the sleeve 1322 moves and engages the gear tooth 1323 and transmits the forward power input through the motor 120 and the one-way clutch 131 to the drive shaft (DA).

That is, the dog clutch 132 combines the sleeve 1322 with the gear teeth 1323 and transmits forward power together with the one-way clutch 131. This can be referred to as a dog clutch engagement state.

In addition, the sleeve 1322 is released for regenerative braking while the dog clutch 132 is engaged and returns to the hub 1321 to transmit reverse power. This can be called clutch release.

Meanwhile, in an electric vehicle, the dog clutch 132 needs to be released while in a manual shift mode (e.g., eco, normal, sport) and driving mode while stopped. For example, when the ECO mode using only the second gear (G2) is activated in the transmission 130 of an electric vehicle, the dog clutch 132 must be released.

In addition, when using the dog clutch 132 and an actuator integrated with the parking mechanism when stopping, the dog clutch 132 must be released when switching from the drive (D) or reverse (R) stage to the parking (P) or neutral (N) stage. Should be.

However, as previously mentioned in the background technology of the invention, in the transmission 130 structure using the one-way clutch 131 and the dog clutch 132, the dog clutch 132 due to backlash of the one-way clutch 131 Unable to release may occur.

For example, Figure 4 shows a phenomenon in which the dog clutch cannot be released due to backlash of the one-way clutch according to an embodiment of the present invention.

Referring to FIG. 4, when forward torque is applied from the one-way clutch 131 connected to the dog clutch 132, displacement due to backlash of the one-way clutch 131 occurs, which causes the dog clutch 132 ) A phase difference occurs between the sleeve 1322 and the gear teeth 1323. However, even in this case, forward power can be transmitted by engaging the dog clutch 132, but when the car stops, the backlash displacement caused by the one-way clutch 131 is restored and the sleeve 1322 and gear teeth of the dog clutch 132 are Stress is generated according to the phase difference between (1323), resulting in a situation in which it is impossible to release the dog clutch (132). At this time, in a state where there is no displacement, the drag clutch 132 fails to release the sleeve 1322 because the sleeve 1322 is fixed and cannot move due to friction caused by the stress of the gear teeth 1323.

Accordingly, when the sleeve release fails, the vehicle controller 150 calculates an estimate of the stress generated between the sleeve 1322 and the gear tooth 1323 of the dog clutch 132, and sends a torque command corresponding to the stress estimate to the motor ( 120), the dog clutch 132 is released through fail safe control, which returns (moves) the sleeve 1322 while the stress is relieved by forward drive.

Here, in order to calculate the stress estimate, the vehicle controller 150 collects the forward torque value generated by the motor 120 while immediately performing engagement control of the dog clutch 1321 and stores it in the memory 151.

Then, the vehicle controller 150 multiplies the forward torque value by a compensation factor for the individual torque performance of the sleeve actuator 134, the inclination state of the vehicle, and the stationary acceleration, and calculates the clutch element (e.g., sleeve tooth, gear tooth) The stress estimate can be calculated by adding the fault diagnosis compensation value to determine the deformation.

The vehicle controller 150 may apply a torque command corresponding to the stress estimate through the motor controller 140 and control the return movement of the sleeve 1322 through the sleeve actuator 134.

In addition, when the sleeve release fails, the vehicle controller 150 manages the degree of deterioration by accumulating the number of dog clutch release function failures in the memory 151, and when release is not possible even through the fail-safe control, it is limited to a failure event and the driver Enters a safe driving mode that provides warnings and limits motor torque output.

Through this, it is possible to induce safe driving control and prompt preventive maintenance by the driver in the event of a transmission component failure.

This vehicle controller 150 may be implemented with one or more processors that operate according to a set program, and the set program is programmed to perform each step of the transmission control method of an electric vehicle for releasing the dog clutch according to an embodiment of the present invention. It may have happened.

This method of controlling the transmission of an electric vehicle will be described in more detail with reference to the drawings below.

Figure 5 shows a fail-safe control state and control conditions for dog clutch release according to an embodiment of the present invention.

6 and 7 are flowcharts schematically showing a transmission control method for an electric vehicle according to an embodiment of the present invention.

Referring to Figures 5 to 7, the vehicle controller 150 according to an embodiment of the present invention collects real-time driving information required for transmission control from the driving information detector 110 (S1).

The vehicle controller 150 can continuously collect driving information including at least one of vehicle speed, APS signal, BPS signal, motor torque, wheel speed, shift gear, vehicle inclination state, and stationary acceleration depending on the vehicle's driving situation. .

The vehicle controller 150 operates the sleeve actuator 134 to release the dog clutch 132 when the vehicle is stopped according to driving information (S2).

At this time, the vehicle controller 150 terminates the fail-safe logic if it succeeds in releasing the dog clutch 132 normally (S3; example), but if it stochastically fails to release the dog clutch 132 in a stopped state (S3; No), the present invention attempts fail safe control according to the embodiment (S4).

Hereinafter, the fail-safe control according to the embodiment of the present invention includes a first fail-safe attempt and a second fail-safe attempt with increased stress when the release fails, depending on the number and success of the vehicle controller 150 attempting to release the dog clutch. Let's explain it by dividing it into parts.

First, the first fail-safe attempt method will be described.

The vehicle controller 150 operates the brake BK through the EPB 160 to prevent oscillation due to forward torque when the vehicle is stopped (S5).

The vehicle controller 150 calculates an estimate of the stress generated between the sleeve 1322 and the gear tooth 1323 of the dog clutch 132 (S6). Here, the vehicle controller 150 extracts from the memory 151 the forward torque value stored while performing engagement control of the dog clutch 1321 immediately before, and determines the individual torque performance of the sleeve actuator 134, the inclination state of the vehicle, It can be calculated by multiplying the forward torque value by a compensation factor for stationary acceleration and then adding a fault diagnosis compensation value for determining deformation of clutch elements (e.g. sleeve teeth, gear teeth).

The vehicle controller 150 applies the first torque command based on the stress estimate to the motor 120 and performs the first fail-safe control to attempt to release the sleeve 1322 while relieving the stress by driving in the forward direction (S7). .

The vehicle controller 150 monitors whether an APS signal by the driver or a creep torque is input by the system setting while releasing the sleeve 1322 (S8). At this time, if the APS signal or creep torque is input (S8; e.g. ), release the brake (BK) operation through the EPB (160) (S9), and cancel the first fail-safe attempt.

On the other hand, the vehicle controller 150 completes the first fail-safe control attempt (S10) without inputting the APS signal or creep torque (S8; No), checks the result (S12), and succeeds in the first release. If it is confirmed (S11; example), the logic is terminated.

However, if it is confirmed that the release of the dog clutch 132 failed as a result of the first fail-safe control attempt (S11; No), the number of release failures is increased by 1 and accumulated and stored in the non-volatile memory 151 (S12). The initial value of the number of release failures is 0, and it accumulates without volatilizing even when the engine is turned off, and the degree of deformation or aging of the clutch element can be predicted depending on the accumulated number or frequency.

Then, the vehicle controller 150 initiates secondary fail-safe control (S13) and attempts to release the sleeve by applying a secondary torque command based on the forward maximum torque, which is stronger than the primary torque command based on the stress estimate (S14). ).

Meanwhile, in the above description, when performing the first fail-safe control and the second fail-safe control, the dog clutch 132 can be released in a general component situation. However, if the clutch cannot be released even with the above secondary fail-safe control method, it is caused by damage or permanent deformation of the dog clutch or the rotating body parts connected to it, so it cannot be released by control until the parts are replaced, and the risk of an accident is high, so the vehicle controller ( 150) supports safe driving mode.

For example, if the vehicle controller 150 receives an APS signal while releasing the sleeve 1322 (S15; example) or confirms that the secondary release is successful as a result of completing the secondary fail-safe control attempt (S17; example), The brake (BK) operation of the EPB 160 is released (S18), and the number of release failures accumulated in the memory 151 is compared with the set reference value (S19).

At this time, the vehicle controller 150 terminates the logic if the accumulated number of release failures does not exceed the set reference value (S19; No), but if the accumulated number of release failures exceeds the set reference value (S19; Yes), An inspection warning for clutch components is displayed through the display device 170, and a vehicle safety mode that limits the motor torque output is entered (S20).

In addition, when the vehicle controller 150 confirms that the secondary release has failed as a result of completing the secondary fail-safe control (S17; No), the vehicle controller 150 maintains the operation of the EPB 160 brake (BK) (S21) , a failure warning of clutch components is displayed through the display device 170, and a vehicle safety mode that limits motor torque generation is entered (S22). In other words, when the number of dog clutch release failures occurs frequently, preventive inspection of clutch parts is encouraged through a warning and vehicle safety mode to prevent major failures in the drive system, and in event situations where dog clutch release is impossible, the clutch Accidents due to vehicle failure can be prevented by warning of component failure and immediately restricting vehicle operation.

As such, according to an embodiment of the present invention, when the dog clutch cannot be released due to displacement due to backlash of the one-way clutch applied to the transmission, it is controlled to be released through fail-safe control, thereby solving the phenomenon of component damage and driving impossibility. There is.

In addition, by accumulating the number and frequency of dog clutch failures to be released, the degree of deterioration and failure of parts is predicted, thereby warning drivers and inducing safe driving, which has the effect of preventing accidents due to drive system failure.

In addition, by improving the phenomenon of dog clutch release inability through software (S/W) that performs clutch alignment control without adding or changing separate hardware (H/W), one-way clutch and dog clutch can be locked in electric vehicles without additional cost. There is an effect of being able to actively apply the installed transmission.

The embodiments of the present invention are not implemented only through the devices and/or methods described above, but can be implemented through programs for realizing functions corresponding to the configuration of the embodiments of the present invention, recording media on which the programs are recorded, etc. This implementation can be easily implemented by an expert in the technical field to which the present invention belongs based on the description of the embodiments described above.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims are also possible. It falls within the scope of rights.

100: Transmission control system
110: Driving information detector
120: motor
130: transmission
131: One-way clutch
132: Dog clutch
1321: hub
1322: sleeve
1323: gear teeth
133: friction clutch
134: sleeve actuator
135: speed sensor
140: Motor controller (MCU)
150: Vehicle controller (VCU/TCU)
151: memory
160:EPB
170: display device

Claims (14)

A motor that generates driving torque;
a transmission that performs multi-stage shifting using a dog clutch in a restrained relationship with a one-way clutch that transmits forward power of the motor;
EPB (Electronic Parking Brake), which operates the brakes electronically;
A motor controller that controls the driving torque of the motor according to the driver's accelerator pedal (Accelerator Position Sensor, APS) signal; and
Controls multi-stage shifting of the transmission according to a torque command based on the APS value, but calculates an estimate of the stress generated between the sleeve and gear teeth of the dog clutch after operating the EPB when the dog clutch fails to be released in a stopped state, and calculates the estimate of the stress a vehicle controller that performs first fail-safe control to return the sleeve in a state of relieving stress through forward drive by applying a base first torque command to the motor;
A transmission control system for an electric vehicle including. According to paragraph 1,
The transmission is,
An input shaft (IN) that receives power from the motor;
An output shaft (OUT) installed parallel to the input shaft (IN) and transmitting power through a multi-stage transmission gear; and
It includes a drive shaft installed parallel to the output shaft (OUT) and transmitting power transmitted through the terminal gear to the drive wheel,
The multi-stage transmission gear is a transmission control system for an electric vehicle including a first gear and a second gear installed to circumscribe each other along the longitudinal direction of the input shaft (IN) and the output shaft (OUT). According to paragraph 2,
The dog clutch is,
A transmission control system for an electric vehicle that combines the sleeve with the gear teeth to transmit forward power with the one-way clutch, releases the coupling for regenerative braking, and returns to the hub to transmit reverse power. According to any one of claims 1 to 3,
The vehicle controller,
A transmission control system for an electric vehicle that collects the forward torque value generated by the motor during immediately preceding engagement control of the dog clutch and stores it in a memory to calculate the stress estimate. According to paragraph 4,
The vehicle controller,
An electric vehicle transmission that calculates the stress estimate by multiplying the forward torque value by a compensation factor for the individual torque performance of the sleeve actuator, the vehicle's inclination state, and stationary acceleration, and adding a fault diagnosis compensation value to determine deformation of the clutch element. control system. According to paragraph 1,
The vehicle controller,
A transmission control system for an electric vehicle that performs secondary fail-safe control by applying a second torque command based on forward maximum torque to the motor when disengaging the clutch through the first fail-safe control fails. According to clause 6,
A transmission control system for an electric vehicle that, when disengaging the clutch through the secondary fail-safe control fails, displays a warning of failure of clutch components through a display device while maintaining operation of the EPB and limits shift gear fixation and motor torque generation. According to paragraph 1,
The vehicle controller,
If the clutch release through the first fail-safe control fails, the number of release failures is increased by 1 and accumulated and stored in the non-volatile memory. If the accumulated number of release failures exceeds the set standard value, a warning is issued to inspect the clutch parts and the motor torque output amount is increased. An electric vehicle transmission control system that limits A transmission control method for an electric vehicle that performs multi-stage shifting including a one-way clutch that transmits forward power of the motor and a dog clutch in a restrained relationship,
Initiating primary fail-safe control and operating the brake through EPB when the dog clutch fails to be released in a stopped state;
calculating an estimate of stress generated between the sleeve and gear teeth of the dog clutch;
Attempting to release the sleeve while relieving stress through forward driving by applying the primary torque command based on the stress estimate to the motor; and
If the clutch release through the first fail-safe control fails, performing a second fail-safe control of attempting to release the sleeve by applying a second torque command based on a forward maximum torque that is stronger than the first torque command;
A transmission control method for an electric vehicle comprising a. According to clause 9,
The step of calculating the stress estimate is,
extracting from a memory a forward torque value stored while immediately performing engagement control of the dog clutch; and
calculating the stress estimate by multiplying the forward torque value by a compensation factor for the individual torque performance of the sleeve actuator, the inclination state of the vehicle, and the stationary acceleration, and then adding a fault diagnosis compensation value for determining deformation of the clutch element;
A transmission control method for an electric vehicle comprising a. According to clause 9,
The step of attempting to release the sleeve is,
Monitoring whether creep torque is input by an APS signal by the driver or by setting to the system while releasing the sleeve; and
When the APS signal or creep torque is input, releasing the brake operation through the EPB and canceling the first fail-safe attempt;
A transmission control method for an electric vehicle comprising a. According to clause 9,
If the clutch release through the first fail-safe control fails, increasing the number of release failures by 1 and cumulatively storing the release failure count in a non-volatile memory. According to clause 12,
A transmission control method for an electric vehicle, including a warning for inspection of clutch components and limiting the amount of motor torque output when the number of release failures accumulated in the memory exceeds a set standard value. According to clause 9,
When it is confirmed that the secondary release has failed as a result of completing the secondary fail-safe control, a vehicle safety system that displays a failure warning of the clutch component through a display device and limits the generation of motor torque while maintaining the brake operation of the EPB How to control the transmission of an electric vehicle entering mode.

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