JP6543540B2 - Belt continuously variable transmission and failure determination method thereof - Google Patents

Description

  The present invention relates to a technology for determining abnormality of a signal from an external device or failure of a sensor, a solenoid valve, or the like in a belt continuously variable transmission (hereinafter referred to as "CVT").

  The CVT is composed of a primary pulley and a secondary pulley whose groove width can be changed, and a belt wound around them. If the groove width of each pulley is changed, the contact radius between the belt and each pulley changes, and the transmission ratio changes steplessly.

  The groove widths of the primary and secondary pulleys are changed by the primary pressure and the secondary pressure supplied to the oil chambers of the pulleys. Also, the belts are pinched between the primary pulley and the secondary pulley by these hydraulic pressures.

  Whether the sensor that detects the primary pressure and the secondary pressure has failed can be determined based on whether or not the combination of detected values is within the normal range. That is, in CVT, since the combination that primary pressure and secondary pressure can take is known in advance from the gear ratio range, input torque, input rotation, etc., one pressure is too high or too low for the other pressure. In this case, it can be determined that the sensor that detects the primary pressure or the secondary pressure is broken.

  Then, when it is determined that the sensor that detects one of the pressures is broken, feedback control of hydraulic control is stopped and switching to feedforward control is performed as disclosed in Patent Document 1 .

Unexamined-Japanese-Patent No. 2010-270798

  The primary pressure and the secondary pressure are adjusted according to the input torque to the CVT to prevent belt slippage, and the input torque to the CVT is determined based on a signal from the engine controller.

  If the signal from the engine controller is abnormal and the input torque to the CVT can not be determined, the indicated value of the secondary pressure is set to a predetermined high pressure, and the primary pressure is feedforward controlled according to the vehicle speed. To be done. As a result, even if the input torque is unknown, it is possible to shift according to the vehicle speed while preventing belt slippage.

  However, when this control is executed, the secondary pressure is always high while the primary pressure is the pressure according to the vehicle speed. Therefore, for example, in a situation where the engine speed is low and the engine speed is high, the secondary pressure is A situation occurs that is too high for the primary pressure. Therefore, when the failure determination of the sensor based on the combination of the primary pressure and the secondary pressure is performed, it is determined that the sensor is broken.

  Furthermore, if it is determined that the sensor that detects the primary pressure or the secondary pressure in addition to the signal abnormality from the engine controller has also failed, fail safe control for double failure will be executed.

  Fail-safe control for double failure is, for example, control for fixing the gear position of the auxiliary transmission mechanism to the second speed and implementing the torque reduction of the engine, in the case of a CVT with an auxiliary transmission mechanism. The purpose of this control is to save the vehicle safely to a safe place, and the effect on the power performance of the vehicle when executed is large, and such control is executed based on an erroneous judgment result. May be undesirable.

  The present invention has been made in view of such technical problems, and when a signal from an external device such as an engine controller is abnormal, a sensor that detects a primary pressure or a secondary pressure that has not failed is broken. The purpose is to make sure that it is not

  According to an aspect of the present invention, there is provided a pressure regulating valve for adjusting the primary pressure supplied to the primary pulley to become the primary command pressure, and a pressure regulating valve for adjusting the secondary pressure supplied to the secondary pulley to be the secondary command pressure. There is provided a belt continuously variable transmission including: a primary pressure sensor that detects the primary pressure; a secondary pressure sensor that detects the secondary pressure; and a controller.

The controller determines whether at least one of the primary pressure sensor and the secondary pressure sensor is broken based on whether the combination of the primary pressure sensor and the detection value of the secondary pressure sensor is in a normal region, and an external device Control the primary indicated pressure according to the vehicle speed and execute failsafe control with the secondary indicated pressure as a fixed value when the signal received from the vehicle is abnormal, and the primary pressure sensor based on the combination of the detected values And prohibiting the failure determination of the secondary pressure sensor.

  Further, according to another aspect of the present invention, there is provided a corresponding method for judging a belt continuously variable failure.

  According to these aspects, when the signal from the external device is abnormal, the failure determination of the primary pressure sensor and the secondary pressure sensor is not performed. Therefore, although either the primary pressure sensor or the secondary pressure sensor is normal, it is not erroneously determined that one of them is broken.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram of the belt continuously variable transmission which concerns on embodiment of this invention. It is a partial schematic block diagram of a hydraulic control circuit. It is a figure for demonstrating the failure determination method of a primary pressure sensor and a secondary pressure sensor. It is a figure showing signs that a primary pressure sensor and a secondary pressure sensor are judged to be in error accidentally. It is the flowchart which showed the processing content of the transmission controller.

  Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

  FIG. 1 is a schematic configuration view of a vehicle equipped with a belt continuously variable transmission according to an embodiment of the present invention. This vehicle is equipped with an engine 1 as a power source. The output rotation of the engine 1 is transmitted to the drive wheels 7 via the torque converter 2, the first gear train 3, the transmission 4, the second gear train 5, and the differential device 6. The second gear train 5 is provided with a parking mechanism 8 which mechanically locks the output shaft of the transmission 4 in a non-rotatable manner during parking.

  The engine 1 is an internal combustion engine such as a gasoline engine or a diesel engine. The engine speed and torque are controlled by the engine controller 13.

  The torque converter 2 includes a lockup clutch 2a. When the lockup clutch 2a is engaged, slippage in the torque converter 2 is eliminated, and the transmission efficiency of the torque converter 2 can be improved.

  In the vehicle, an oil pump 10 driven by utilizing a part of the power of the engine 1, and a hydraulic control circuit 11 which regulates the hydraulic pressure from the oil pump 10 and supplies it to each part of the transmission 4; A transmission controller 12 for controlling the hydraulic control circuit 11 is provided.

  The transmission 4 is a continuously variable transmission provided with a variator 20 and an auxiliary transmission mechanism 30 provided in series with the variator 20. “To be provided in series” means that the variator 20 and the auxiliary transmission mechanism 30 are provided in series in the power transmission path from the engine 1 to the drive wheels 7. In this example, the auxiliary transmission mechanism 30 is provided on the output side of the variator 20, but the auxiliary transmission mechanism 30 may be provided on the input side.

  The variator 20 is a continuously variable transmission mechanism including a primary pulley 21, a secondary pulley 22, and a belt 23 wound around the pulleys 21 and 22. The pulleys 21 and 22 are disposed in a state in which the sheave surfaces are opposed to the fixed conical plates 21f and 22f and the fixed conical plates 21f and 22f, respectively, and form movable grooves between the fixed conical plates 21f and 22f. It is provided with plates 21m and 22m, and hydraulic cylinders 21p and 22p provided on the back of the movable conical plates 21m and 22m for axially displacing the movable conical plates 21m and 22m. As the belt 23, although a metal belt, a rubber belt, a chain type belt etc. can be mentioned as an example, it is not particularly limited.

  When the hydraulic pressure (primary pressure Ppri and secondary pressure Psec) supplied to the pulleys 21 and 22 is adjusted, the force with which the pulleys 21 and 22 clamp the belt 23 changes, and the torque capacity (maximum transmittable torque) of the variator 20 becomes The groove width changes, and the contact radius between the belt 23 and the pulleys 21 and 22 changes, and the transmission ratio of the variator 20 changes steplessly.

  The auxiliary transmission mechanism 30 is a transmission mechanism having two forward gears and one reverse gear. The auxiliary transmission mechanism 30 includes a Ravigneaux type planetary gear mechanism 31 in which carriers of two planetary gears are connected, and a plurality of friction elements (Low brake 32, High clutch 33, Rev brake 34). By adjusting the hydraulic pressure supplied to the friction elements 32-34 and changing the engagement state of the friction elements 32-34, the gear position of the auxiliary transmission mechanism 30 is changed.

  The transmission controller 12 includes a CPU, a storage device including a RAM and a ROM, an input / output interface, and a bus connecting these components to one another.

Various signals are input to the transmission controller 12 via an input / output interface. The following signals can be input:
A signal from an accelerator opening degree sensor 41 which detects an accelerator opening degree APO representing an operation amount of an accelerator pedal A signal from a primary rotational speed sensor 42 which detects a primary rotational speed Npri which is a rotational speed of the primary pulley 21 A signal from an output rotational speed sensor 43 for detecting an output rotational speed (a vehicle speed) of 4 A signal from a line pressure sensor 44 for detecting a line pressure PL A signal from a primary pressure sensor 45 for detecting a primary pressure Ppri Signal from secondary pressure sensor 46 detecting pressure Psec Signal from inhibitor switch 47 detecting position of select lever Signal from secondary rotation speed sensor 48 detecting secondary rotation speed Nsec which is rotation speed of secondary pulley 22・ Engine controller 13 Et state of operation the engine 1 (rotational speed, torque), and the signal indicating.

  The storage device of the transmission controller 12 stores a transmission control program of the transmission 4 and a transmission map used in the transmission control program. The transmission controller 12 reads out the transmission control program stored in the storage device and causes the CPU to execute it, thereby performing predetermined arithmetic processing on the signal input via the input interface, and performing each operation of the transmission 4 The instruction pressure of the hydraulic pressure supplied to the part is set, and the set instruction pressure is output to the hydraulic control circuit 11 through the input / output interface. In addition, the transmission controller 12 outputs an engine control signal (for example, a torque down signal) to the engine controller 13 as necessary.

  The hydraulic control circuit 11 is composed of a plurality of flow paths and a plurality of hydraulic control valves. The hydraulic control circuit 11 controls the plurality of hydraulic control valves based on the command pressure from the transmission controller 12 to switch the supply path of the hydraulic pressure, and generates the hydraulic pressure according to the command pressure. Supply to the site. Thereby, the shift of the variator 20, the change of the shift position of the auxiliary transmission mechanism 30, the displacement control of the friction elements 32 to 34, and the engagement / release of the lockup clutch 2a are performed.

  FIG. 2 shows a portion of the hydraulic control circuit 11, which is related to the shift of the variator 20.

  The line pressure solenoid valve 61 is a drain pressure regulation type solenoid valve that regulates the line pressure PL to the line command pressure by draining and reducing a part of the discharge pressure of the oil pump 10.

  The primary pressure solenoid valve 62 and the secondary pressure solenoid valve 63 drain and reduce a portion of the line pressure PL with the line pressure PL as the original pressure, thereby reducing the primary pressure Ppri and the secondary pressure Psec to the primary indication pressure and the secondary indication, respectively. It is a drain pressure regulation type solenoid valve that regulates pressure to pressure.

  The solenoid valves 61 to 63 respectively have feedback circuits 61f, 62f, 63f for returning the hydraulic pressure after pressure regulation to the pressure regulation valve and performing feedback control of the hydraulic pressure after pressure regulation to the command pressure. The command pressure is commanded to the solenoid valves 61-63 in the form of a command current to the solenoid valves 61-63. Also, the solenoid valves 61 to 63 are normally high solenoid valves in which the output hydraulic pressure with respect to the input hydraulic pressure is maximized when the indicated current is 0 mA.

  With such a configuration, the hydraulic pressure control circuit 11 can adjust the primary pressure Ppri and the secondary pressure Psec independently with the line pressure PL as the source pressure.

  By the way, the transmission controller 12 monitors and determines whether the signals from the sensors 41 to 48, the solenoid valves 61 to 63, and the engine controller 13 are normal, and determines whether any abnormality has occurred. Fail safe control is performed.

  For example, the transmission controller 12 determines whether the combination of the primary pressure Ppri detected by the primary pressure sensor 45 and the secondary pressure Psec detected by the secondary pressure sensor 46 is within the normal range shown in FIG. The normal region is set based on the combination that the primary pressure Ppri and the secondary pressure Psec can normally take in accordance with the torque and rotational speed input from the engine 1 to the variator 20, the gear ratio of the variator 20, and the like. When the combination of the detected values of the primary pressure Ppri and the secondary pressure Psec leaves the normal region and enters the failure region, the transmission controller 12 causes either the primary pressure sensor 45 or the secondary pressure sensor 46 to fail. Judge that there is (deviation detection).

  If it is determined that either the primary pressure sensor 45 or the secondary pressure sensor 46 is broken, the transmission controller 12 switches control of the primary pressure Ppri and the secondary pressure Psec from feedback control to feedforward control. Furthermore, the transmission controller 12 increases the secondary command pressure by a predetermined value to prevent belt slippage due to lack of hydraulic pressure.

  In addition, if the signal input from the engine controller 13 to the transmission controller 12 is abnormal due to disconnection of the signal line, a failure of the engine controller 13 itself, etc., the torque of the engine 1, that is, the input torque to the variator 20 becomes unclear. Therefore, the transmission controller 12 sets the command current to the secondary pressure solenoid valve 63 to 0 mA, that is, maximizes the secondary command pressure, so that the output hydraulic pressure to the input hydraulic pressure of the secondary pressure solenoid valve 63 is maximized, The secondary pressure Psec is increased to prevent the belt 23 from slipping due to insufficient holding pressure. For the primary pressure solenoid valve 62, the transmission controller 12 sets the primary command pressure (command current) to a value corresponding to the vehicle speed, and based on this, performs feedforward control of the primary pressure Ppri, thereby changing the speed according to the vehicle speed. To achieve.

  Also, if the transmission controller 12 determines that a double failure has occurred at multiple locations, fail safe control for double failure to safely save the vehicle to a safe place Run. In this control, for example, the transmission controller 12 fixes the gear position of the sub transmission mechanism 30 to the second speed, and instructs the engine controller 13 to execute the torque reduction of the engine 1.

  However, when the signal from the engine controller 13 is determined to be abnormal and the fail safe control is being performed, the primary pressure sensor 45 and the secondary pressure sensor 46 based on the combination of the detected values of the primary pressure Ppri and the secondary pressure Psec. If neither the primary pressure sensor 45 nor the secondary pressure sensor 46 has failed, it is erroneously determined that one of them has failed, and failsafe for double failure is performed. It may be executed.

  FIG. 4 shows the situation at that time.

  When it is determined that the signal from the engine controller 13 is abnormal and the failsafe control is being performed, as described above, the secondary hydraulic pressure of the secondary pressure solenoid valve 63 is maximized with respect to the input hydraulic pressure. The indicated current to the solenoid valve 63 is 0 mA, that is, the secondary indicated pressure is maximized, and the secondary pressure Psec is increased. The primary pressure Ppri is controlled in accordance with the vehicle speed.

  Therefore, for example, when the vehicle speed is low and the rotational speed of the engine 1 is high, the secondary pressure Psec is too high relative to the primary pressure Ppri, and the combination of the detection values of the primary pressure Ppri and the secondary pressure Psec is It leaves the normal area and enters the failure area (point X in the figure → point Y).

  As a result, although both the primary pressure sensor 45 and the secondary pressure sensor 46 are normal, it is erroneously determined that one of them has failed.

  If it is determined that either the primary pressure sensor 45 or the secondary pressure sensor 46 has failed following a signal abnormality from the engine controller 13, fail-safe control for double failure is executed, but double failure As described above, since the fail-safe control for safety is a fail-safe control that places importance on safety, it has a large influence on the running performance, and it is not preferable that such control is executed based on an erroneous judgment result.

  Therefore, when the transmission controller 12 determines that the signal from the engine controller 13 is abnormal, it determines the failure of the primary pressure sensor 45 and the secondary pressure sensor 46 based on the combination of the detected values of the primary pressure Ppri and the secondary pressure Psec. Prohibit

  FIG. 5 shows the processing contents of the transmission controller 12 for that purpose.

  According to this, when the transmission controller 12 determines that the signal from the engine controller 13 is abnormal, it advances the process from step S1 to steps S2 and S3. Then, the transmission controller 12 executes failsafe control (secondary indicated pressure = maximum pressure) when the signal from the engine controller 13 is abnormal, and prohibits the failure determination of the primary pressure sensor 45 and the secondary pressure sensor 46. Do.

  Thereby, when the signal from the engine controller 13 is abnormal, the failure judgment of the primary pressure sensor 45 and the secondary pressure sensor 46 is not performed, and both the primary pressure sensor 45 and the secondary pressure sensor 46 are normal. Nevertheless, there is no possibility that one of them is erroneously determined to be faulty (effects corresponding to claims 1, 2 and 7).

  Further, since the secondary indication pressure is set to the maximum pressure (the indication current is 0 mA), belt slippage can be prevented even in a situation where the torque input from the engine 1 to the variator 20 is unclear (claims) Effects corresponding to items 3 and 4).

  Furthermore, since it is no longer judged to be a double failure, it is judged to be a double failure and fail safe control for a double failure is executed, the secondary transmission mechanism 30 is fixed at the second speed, and the traveling performance is greatly reduced. There is no problem (effect corresponding to claim 5).

  As described above, the transmission controller 12 executes the failsafe control according to the failure point, but when the ignition key is turned off, the failsafe control under execution ends at that timing. Then, when the ignition key is turned on again and the vehicle restarts again, it is judged again whether the signal from the engine controller 13 is abnormal or not, the sensor, the solenoid valve, etc. are broken again, and the abnormality or malfunction If it is judged again that there is a failure safe control is to be executed again.

  This is because the failure may be resolved when the ignition key is turned on again, and in this case, unnecessary failsafe control is executed to deteriorate the traveling performance at the time of vehicle restart. This can be prevented (the effect corresponding to claim 6).

  As mentioned above, although embodiment of this invention was described, the said embodiment is only what showed one of the application examples of this invention, and the meaning which limits the technical scope of this invention to the specific structure of the said embodiment is not.

  For example, in the above embodiment, if the signal from the engine controller 13 is abnormal, the secondary command pressure is set to the maximum pressure, but it is not limited to the maximum pressure because it may be a predetermined high pressure that can prevent belt slippage.

  Further, although the above embodiment executes failsafe control that raises the secondary pressure Psec to a predetermined high pressure if the signal from the engine controller 13 is abnormal, the present invention is directed to the transmission controller 12 from an external device. The present invention can be applied as long as the primary pressure Ppri or the secondary pressure Psec is fixed to a predetermined pressure when there is any abnormality in the input signal.

4 belt continuously variable transmission 12 transmission controller 13 engine controller 21 primary pulley 22 secondary pulley 30 secondary transmission mechanism 45 primary pressure sensor 46 secondary pressure sensor 62 primary pressure solenoid valve 63 secondary pressure solenoid valve

Claims (7)

It is a belt continuously variable transmission,
A pressure control valve for adjusting the primary pressure supplied to the primary pulley to become the primary command pressure;
A pressure control valve for adjusting the secondary pressure supplied to the secondary pulley to become the secondary command pressure;
A primary pressure sensor that detects the primary pressure;
A secondary pressure sensor that detects the secondary pressure;
Controller,
Equipped with
The controller
It is determined whether at least one of the primary pressure sensor and the secondary pressure sensor is broken based on whether a combination of the detection value of the primary pressure sensor and the detection value of the secondary pressure sensor is in a normal region,
When a signal received from an external device is abnormal, the primary indication pressure is controlled according to the vehicle speed, and failsafe control is performed with the secondary indication pressure as a fixed value, and the primary based on a combination of the detection values Prohibit failure judgment of the pressure sensor and the secondary pressure sensor,
Belt continuously variable transmission characterized in that. The belt continuously variable transmission according to claim 1, wherein
The external device is an engine controller,
Belt continuously variable transmission characterized by The belt continuously variable transmission according to claim 1 or 2, wherein
The fail safe control is control to make the secondary command pressure the maximum pressure,
Belt continuously variable transmission characterized by The belt continuously variable transmission according to claim 3, wherein
The pressure regulating valve for which the maximum pressure is instructed by the fail safe control is a normal high type solenoid valve in which the output oil pressure with respect to the input oil pressure is maximized when the instruction current is 0 mA,
The fail safe control is control to set an indication current to the normal high type solenoid valve to 0 mA.
Belt continuously variable transmission characterized by The belt continuously variable transmission according to any one of claims 1 to 4, wherein
The auxiliary transmission mechanism further includes a first shift speed and a second shift speed having a smaller gear ratio than the first shift speed.
When the controller determines that at least one of the primary pressure sensor and the secondary pressure sensor is defective and the signal received from the external device is abnormal, the controller sets the gear position of the auxiliary transmission mechanism to the second gear position. Further configured to be fixed in two gear positions,
Belt continuously variable transmission characterized by The belt continuously variable transmission according to any one of claims 1 to 5, wherein
The controller is further configured to release the failsafe control when an ignition key is turned off.
Belt continuously variable transmission characterized by A pressure regulating valve that adjusts the primary pressure supplied to the primary pulley to the primary command pressure, a pressure regulator that adjusts the secondary pressure supplied to the secondary pulley to the secondary command pressure, and a primary pressure that detects the primary pressure It is a failure judging method of a belt continuously variable transmission provided with a sensor and a secondary pressure sensor which detects the above-mentioned secondary pressure,
It is determined whether at least one of the primary pressure sensor and the secondary pressure sensor is broken based on whether a combination of the detection value of the primary pressure sensor and the detection value of the secondary pressure sensor is in a normal region,
When a signal received from an external device is abnormal, the primary indication pressure is controlled according to the vehicle speed, and failsafe control is performed with the secondary indication pressure as a fixed value, and the primary based on a combination of the detection values Prohibit failure judgment of the pressure sensor and the secondary pressure sensor,
A method of judging failure of a belt continuously variable transmission characterized in that.

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