Vehicle control device

Abstract

To appropriately determine an abnormal state of a control valve.SOLUTION: A vehicle control device comprises: a continuously variable transmission having a primary oil chamber and a secondary oil chamber; an oil pump pumping hydraulic oil to the primary and secondary oil chambers; a control valve supplying the hydraulic oil to the primary oil chamber when the continuously variable transmission performs upshift; and a control system controlling the continuously variable transmission through the control valve. The control system sets an upper limit transmission speed on the basis of a transmission gear ratio of the continuously variable transmission when the upshift is started in a stepped transmission mode in which a transmission gear ratio of the continuously variable transmission is controlled in stages. The control system determines that the control valve is in an abnormal state when a transmission speed of the continuously variable transmission exceeds the upper limit transmission speed during the upshift in the stepped transmission mode.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device provided in a vehicle. [Background technology]

[0002] Vehicles such as automobiles are equipped with continuously variable transmissions consisting of a primary pulley and a secondary pulley (see Patent Documents 1 to 3). When changing gears in this continuously variable transmission, hydraulic control is performed on the primary pulley and the secondary pulley. This makes it possible to control the groove width of the primary pulley and the secondary pulley, and to change the winding diameter of the drive chain around each pulley, allowing the continuously variable transmission to shift to a low or high gear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-78371 [Patent Document 2] JP 2018-54027 A [Patent Document 3] JP 2020-172983 A Summary of the Invention [Problem to be solved by the invention]

[0004] Furthermore, when controlling the gear ratio of a continuously variable transmission, it is common to use a control valve to control the supply of hydraulic oil to the primary pulley. Furthermore, the control valve can be used to control the flow rate of hydraulic oil, thereby controlling the speed change speed of the continuously variable transmission. However, when wear occurs in the spool, housing, or other components of the control valve, the gap between the components increases, changing the cross-sectional area of ​​the flow path within the control valve, making it difficult to properly control the speed change speed of the continuously variable transmission. In other words, because wear in the control valve reduces the control accuracy of the continuously variable transmission, it is necessary to properly determine abnormal conditions caused by wear in the control valve.

[0005] An object of the present invention is to appropriately determine an abnormal state of a control valve. [Means for solving the problem]

[0006] A vehicle control device according to one embodiment is a vehicle control device provided in a vehicle, and includes a continuously variable transmission having a primary pulley including a primary oil chamber and a secondary pulley including a secondary oil chamber. The vehicle control device includes: an oil pump connected to the primary oil chamber and the secondary oil chamber, for pumping hydraulic oil to the primary oil chamber and the secondary oil chamber; The vehicle control device includes: a control valve that is provided in an oil passage that connects the oil pump and the primary oil chamber and that supplies hydraulic oil to the primary oil chamber when the continuously variable transmission is upshifted; The vehicle control device includes: A control system including a processor and a memory communicatively connected to each other, the control system controlling the continuously variable transmission via the control valve. It has. The control system controls the gear ratio of the continuously variable transmission stepwise at the start of an upshift in a step shift mode. The larger Upper limit shift speed high setting do. The control system determines that the control valve is in an abnormal state when the shift speed of the continuously variable transmission exceeds the upper limit shift speed during an upshift in the step shift mode. [Effects of the Invention]

[0007] In one embodiment, the vehicle control device sets an upper limit shift speed based on the gear ratio of the continuously variable transmission at the start of an upshift in a step shift mode that controls the gear ratio of the continuously variable transmission in steps, and determines that the control valve is in an abnormal state if the shift speed of the continuously variable transmission exceeds the upper limit shift speed during the upshift in the step shift mode. This makes it possible to appropriately determine the abnormal state of the control valve. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing an example of the configuration of a vehicle equipped with a vehicle control device according to an embodiment of the present invention; [Figure 2] FIG. 1 is a diagram illustrating an example of the configuration of a vehicle control device. [Figure 3] FIG. 2 is a diagram simply illustrating the basic structure of each control unit. [Figure 4] FIG. 4 is a diagram showing an example of a target gear position used in a step shift mode. [Figure 5] FIG. 4 is a diagram showing an example of a target gear position set based on a vehicle speed and an accelerator opening degree. [Figure 6] FIG. 2 is a simplified diagram showing a part of a hydraulic circuit that constitutes the valve body. [Figure 7] FIG. 4 is a diagram illustrating the operation of an upshift valve and a downshift valve during a downshift. [Figure 8] 10A and 10B are diagrams illustrating the operation states of an upshift valve and a downshift valve during an upshift. [Figure 9] 4 is a flowchart showing an example of a procedure for executing valve wear determination control. [Figure 10] FIG. 10 is a diagram showing an example of an upper limit shift speed used in valve wear determination control. [Figure 11] 4 is a timing chart showing an example of an execution state of valve wear determination control. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. In the following description, identical or substantially identical configurations and elements are designated by the same reference numerals and will not be described again.

[0010] [Vehicle configuration] Fig. 1 is a diagram showing an example of the configuration of a vehicle 11 equipped with a vehicle control device 10 according to one embodiment of the present invention. As shown in Fig. 1, the vehicle 11 is equipped with a powertrain 14 including an engine 12 and a continuously variable transmission 13. Wheels 18 are connected to an output shaft 15 of the powertrain 14 via a propeller shaft 16 and a differential mechanism 17. The powertrain 14 shown in the figure is a rear-wheel drive powertrain, but is not limited to this and may be a front-wheel drive or all-wheel drive powertrain.

[0011] Fig. 2 is a diagram showing an example configuration of a vehicle control device 10. As shown in Fig. 2, a powertrain 14 has a continuously variable transmission 13 consisting of a primary pulley 20, a secondary pulley 21, and a drive chain 22. The engine 12 is connected to the primary pulley 20 of the continuously variable transmission 13 via a primary shaft 23, a forward / reverse switching mechanism 24, and a torque converter 25. The wheels 18 are connected to the secondary pulley 21 of the continuously variable transmission 13 via a secondary shaft 26, an output shaft 15, a propeller shaft 16, and a differential mechanism 17. The forward / reverse switching mechanism 24, which switches the rotation direction of the primary pulley 20, is composed of a forward clutch, a reverse brake, a planetary gear train, and the like, all of which are not shown.

[0012] The primary pulley 20 of the continuously variable transmission 13 has a fixed sheave 30 fixed to the primary shaft 23 and a movable sheave 31 provided on the primary shaft 23 so as to be movable in the axial direction. A primary oil chamber 32 is defined on the back side of the movable sheave 31, and by controlling the hydraulic oil pressure (primary pressure) supplied to this primary oil chamber 32, the movable sheave 31 can be moved to change the groove width between the sheaves 30, 31. Similarly, the secondary pulley 21 of the continuously variable transmission 13 has a fixed sheave 33 fixed to the secondary shaft 26 and a movable sheave 34 provided on the secondary shaft 26 so as to be movable in the axial direction. A secondary oil chamber 35 is defined on the back side of the movable sheave 34, and by controlling the hydraulic oil pressure (secondary pressure) supplied to this secondary oil chamber 35, the movable sheave 34 can be moved to change the groove width between the sheaves 33, 34. In other words, by controlling the hydraulic pressure to the primary oil chamber 32 and the secondary oil chamber 35, the pulley groove width can be changed to change the winding diameter of the drive chain 22, thereby allowing the continuously variable transmission 13 to change speeds.

[0013] In order to control the continuously variable transmission 13, forward / reverse switching mechanism 24, and the like that constitute the powertrain 14, a valve body 36 consisting of a plurality of electromagnetic valves, oil passages, and the like is provided in the powertrain 14. An oil pump 37 driven by the engine 12, etc. is connected to the valve body 36. The hydraulic oil pumped from the oil pump 37 passes through the valve body 36, where the supply destination, pressure, and the like are controlled, and the oil is supplied to the continuously variable transmission 13, forward / reverse switching mechanism 24, and the like. In order to control the continuously variable transmission 13, etc. via the valve body 36, a shift control unit 38 is connected to the valve body 36.

[0014] An intake manifold 40 of the engine 12 is provided with a throttle valve 41 that adjusts the amount of intake air. The engine 12 is also provided with an injector 42 that injects fuel into the intake port and cylinder, and an ignition device 43 that includes an igniter, a spark plug, etc. In order to control the operating conditions of the engine 12, an engine control unit 44 is connected to the throttle valve 41, the injector 42, the ignition device 43, etc.

[0015] [Control System] As shown in FIG. 2 , the vehicle control device 10 is provided with a control system 50 consisting of multiple electronic control units to control the powertrain 14 and the like. The electronic control units constituting the control system 50 include the aforementioned transmission control unit 38 and engine control unit 44, as well as a vehicle control unit 51 that outputs control signals to these control units 38, 44. These control units 38, 44, 51 are communicably connected to one another via an in-vehicle network 52 such as CAN or LIN. The vehicle control unit 51 sets operation targets for the engine 12, the continuously variable transmission 13, and the like based on input information from the various control units 38, 44, 51 and various sensors described below. The vehicle control unit 51 then generates control signals corresponding to the operation targets of the engine 12, the continuously variable transmission 13, and the like, and outputs these control signals to the various control units 38, 44.

[0016] Sensors connected to the vehicle control unit 51 include a vehicle speed sensor 60 that detects the vehicle speed, which is the traveling speed of the vehicle 11, an engine rotation speed sensor 61 that detects the engine rotation speed, which is the rotation speed of the engine 12, an accelerator sensor 62 that detects the amount of accelerator pedal operation (hereinafter referred to as accelerator opening), and a brake sensor 63 that detects the amount of brake pedal operation. Sensors connected to the vehicle control unit 51 also include a primary rotation speed sensor 64 that detects the rotation speed of the primary pulley 20 and a secondary rotation speed sensor 65 that detects the rotation speed of the secondary pulley 21. A start switch 66 that is operated by the driver when starting up the control system 50 is also connected to the vehicle control unit 51. A display 67 that displays notification information for the driver is also connected to the vehicle control unit 51.

[0017] Fig. 3 is a diagram simply illustrating the basic structure of each of the control units 38, 44, and 51. As shown in Fig. 3, each of the control units 38, 44, and 51 has a microcontroller 72 incorporating a processor 70, a memory 71, and the like. A predetermined program is stored in the memory 71, and an instruction set of the program is executed by the processor 70. The processor 70 and the memory 71 are connected to each other so that they can communicate with each other. In the illustrated example, one processor 70 and one memory 71 are incorporated in the microcontroller 72, but this is not limiting, and multiple processors 70 may be incorporated in the microcontroller 72, and multiple memories 71 may be incorporated in the microcontroller 72.

[0018] Each control unit 38, 44, 51 is also provided with an input conversion circuit 73, a drive circuit 74, a communication circuit 75, an external memory 76, a power supply circuit 77, etc. The input conversion circuit 73 converts signals input from various sensors into signals that can be input to the microcontroller 72. The drive circuit 74 generates drive signals for actuators such as the valve body 36 based on signals output from the microcontroller 72. The communication circuit 75 converts signals output from the microcontroller 72 into communication signals for other control units. The communication circuit 75 also converts communication signals received from other control units into signals that can be input to the microcontroller 72. The power supply circuit 77 supplies a stable power supply voltage to the microcontroller 72, the input conversion circuit 73, the drive circuit 74, the communication circuit 75, the external memory 76, etc. The external memory 76, such as a nonvolatile memory, stores data that should be retained even when power is off.

[0019] [Step speed change mode] As an example of a control mode for changing the speed of continuously variable transmission 13, a step shift mode in which the gear ratio is controlled in stages will be described. Fig. 4 is a diagram showing an example of a target gear used in the step shift mode, and Fig. 5 is a diagram showing an example of a target gear set based on the vehicle speed and the accelerator opening. In Fig. 4, characteristic line Low indicates the maximum low-side gear ratio that can be controlled by continuously variable transmission 13, and characteristic line High indicates the minimum high-side gear ratio that can be controlled by continuously variable transmission 13. The gear ratio is the ratio (Np / Ns) of the rotational speed of primary pulley 20 (primary rotational speed Np) to the rotational speed of secondary pulley 21 (secondary rotational speed Ns). Therefore, a larger value of the gear ratio means a lower gear ratio, and a smaller value of the gear ratio means a higher gear ratio.

[0020] As shown in FIG. 4, in the step shift mode in which the gear ratio is controlled in stages, a plurality of fixed gear ratios R1 to R6 are set as examples of target gear ratios of the continuously variable transmission 13, that is, pseudo target gears. Also, as shown in FIG. 5, the control system 50 sets the target gear in the step shift mode based on the vehicle speed and the accelerator pedal position. That is, the control system 50 sets a higher target gear as the vehicle speed increases, and sets a lower target gear as the vehicle speed decreases. Also, the control system 50 sets a higher target gear as the accelerator pedal position decreases, and sets a lower target gear as the accelerator pedal position increases. Then, once the target gear is set based on the vehicle speed and the accelerator pedal position as described above, the continuously variable transmission 13 is upshifted or downshifted toward this target gear. In the step shift mode, the target gear may not only be automatically changed based on the vehicle speed and accelerator opening, but also may be changed based on the driver's manual operation such as shift lever operation or paddle operation.

[0021] [Valve body] Next, the valve body 36 that controls the supply of hydraulic oil to the primary pulley 20 and the secondary pulley 21 will be described. FIG. 6 is a simplified diagram showing a portion of the hydraulic circuit that constitutes the valve body 36. As shown in FIG. 6, an oil pump 37, such as a trochoid pump or a gear pump, is connected to the valve body 36. The oil pump 37, driven by the engine 12 or the like, draws hydraulic oil stored in an oil pan 80 and pumps the hydraulic oil toward the primary pulley 20 and the secondary pulley 21. A line pressure passage 81 is connected to the discharge port of this oil pump 37, and a line pressure control valve 82 that adjusts the line pressure PL of the base hydraulic pressure is connected to the line pressure passage 81. In addition, the line pressure passage 81, through which the hydraulic oil adjusted to the line pressure PL flows, branches into a branch oil passage 83 leading to the primary pulley 20 and a branch oil passage 84 leading to the secondary pulley 21.

[0022] One branch oil passage 83 branching from line pressure passage 81 is connected to primary oil chamber 32 of primary pulley 20 via an upshift valve (control valve) 85 and primary oil passages 86 and 87. In this way, oil pump 37 and primary oil chamber 32 are connected via oil passage 88 consisting of line pressure passage 81, branch oil passage 83, and primary oil passages 86 and 87, and this oil passage 88 is provided with an upshift valve 85. In addition, a downshift valve 90 is connected to primary oil chamber 32 of primary pulley 20 via primary oil passages 87 and 89. Furthermore, the other branch oil passage 84 branching from line pressure passage 81 is connected to secondary oil chamber 35 of secondary pulley 21 via a secondary control valve 91 and secondary oil passage 92.

[0023] The illustrated line pressure control valve 82, secondary control valve 91, upshift valve 85, and downshift valve 90 are pilot-operated valves whose operating states are controlled by pilot fluid. Pilot pressure P1 is supplied to the line pressure control valve 82 from a solenoid valve 82a, and the line pressure control valve 82 adjusts the line pressure PL in accordance with the magnitude of pilot pressure P1. Pilot pressure P2 is supplied to the secondary control valve 91 from a solenoid valve 91a, and the secondary control valve 91 adjusts the secondary pressure in accordance with the magnitude of pilot pressure P2. Pilot pressure P3 is supplied to the upshift valve 85 from a solenoid valve 85a, and the upshift valve 85 adjusts the flow rate to the primary oil chamber 32 during an upshift in accordance with the magnitude of pilot pressure P3. Meanwhile, pilot pressure P4 is supplied to the downshift valve 90 from a solenoid valve 90a, and the downshift valve 90 adjusts the flow rate from the primary oil chamber 32 during a downshift in accordance with the magnitude of pilot pressure P4.

[0024] Upshift valve 85 has a housing 100 and a spool 101 movably accommodated therein. An input port 102 and an output port 103 are formed in housing 100 of upshift valve 85. A branch oil passage 83, through which hydraulic oil adjusted to line pressure PL flows, is connected to input port 102 of housing 100, and a primary oil passage 86, which communicates with primary oil chamber 32, is connected to output port 103 of housing 100. In addition, in order to operate spool 101 of upshift valve 85, a spring member 104 is attached to one end of spool 101, and a pilot pressure chamber 105 is defined at the other end of spool 101. A pilot port 106, which communicates with pilot pressure chamber 105, is formed in housing 100, and a pilot pressure passage 107 is connected to pilot port 106. A solenoid valve 85a controlled by the transmission control unit 38 is connected to the pilot pressure passage 107, and the pilot pressure chamber 105 is supplied with a pilot pressure P3 adjusted by the solenoid valve 85a.

[0025] The downshift valve 90 has a housing 110 and a spool 111 movably accommodated therein. An input port 112 and a discharge port 113 are formed in the housing 110 of the downshift valve 90. A primary oil passage 89 that communicates with the primary oil chamber 32 is connected to the input port 112 of the housing 110, and a discharge oil passage 118 that leads to the oil pan 80 is connected to the discharge port 113 of the housing 110. In addition, in order to operate the spool 111 of the downshift valve 90, a spring member 114 is attached to one end of the spool 111, and a pilot pressure chamber 115 is defined at the other end of the spool 111. A pilot port 116 that communicates with the pilot pressure chamber 115 is formed in the housing 110, and a pilot pressure passage 117 is connected to the pilot port 116. A solenoid valve 90a controlled by the transmission control unit 38 is connected to the pilot pressure passage 117, and the pilot pressure chamber 115 is supplied with a pilot pressure P4 adjusted by the solenoid valve 90a.

[0026] The secondary pressure regulated by the secondary control valve 91, i.e., the secondary pressure supplied to the secondary oil chamber 35, is controlled based on the target gear position, input torque, etc., from the viewpoint of preventing slippage of the drive chain 22. The primary pressure regulated by the upshift valve 85 and the downshift valve 90, i.e., the primary pressure supplied to the primary oil chamber 32, is controlled based on the target gear position, secondary pressure, etc., from the viewpoint of controlling the gear ratio of the continuously variable transmission 13. The valve body 36 is provided with a plurality of pressure sensors (not shown), which detect the line pressure, primary pressure, secondary pressure, etc.

[0027] [Downshift] FIG. 7 shows the operation of the upshift valve 85 and the downshift valve 90 during a downshift. As shown in FIG. 7, during a downshift, the supply of pilot pressure P3 from the electromagnetic valve 85a is cut off, and the spool 101 of the upshift valve 85 is held in a position moved in the direction of arrow A1 by spring force. In other words, the input port 102 and the output port 103 of the upshift valve 85 are cut off from each other, and the upshift valve 85 is held in a cut-off state with no hydraulic oil supplied. During a downshift, the pilot pressure P4 is increased by the electromagnetic valve 90a, causing the spool 111 of the downshift valve 90 to move in the direction of arrow B1 against the spring force. This connects the input port 112 and the discharge port 113 of the downshift valve 90 to each other, allowing hydraulic oil in the primary oil chamber 32 to be discharged from the input port 112 through the discharge port 113, as shown by arrow FL1.

[0028] That is, as shown by arrow X1 in Figure 6, hydraulic oil is discharged from the primary oil chamber 32 via the downshift valve 90, and the primary pressure in the primary oil chamber 32 drops, causing the movable sheave 31 of the primary pulley 20 to move away from the fixed sheave 30. Furthermore, because the winding diameter of the drive chain 22 around the primary pulley 20 decreases, the movable sheave 34 of the secondary pulley 21 moves closer to the fixed sheave 33 so as to increase the winding diameter of the drive chain 22 around the secondary pulley 21. In this way, hydraulic oil is discharged from the primary oil chamber 32 via the downshift valve 90, and the primary pressure in the primary oil chamber 32 drops. This allows the winding diameter of the drive chain 22 around the primary pulley 20 to decrease, and the gear ratio of the continuously variable transmission 13 to be changed to a lower gear (low side).

[0029] 7, a tapered notch 120 is formed on the outer peripheral surface of the valve element 119 provided on the spool 111. In other words, when the input port 112 and the discharge port 113 of the downshift valve 90 are to be communicated with each other, the input port 112 and the discharge port 113 are communicated with each other via the notch 120 of the spool 111. Because the notch 109, which functions as this communication flow path, is formed in a tapered shape, the cross-sectional area of ​​the flow path that communicates the input port 112 and the discharge port 113 can be adjusted by adjusting the stopping position of the spool 111 using the magnitude of the pilot pressure P4. In other words, by adjusting the stopping position of the spool 111 using the pilot pressure P4, the flow rate of hydraulic oil flowing from the input port 112 to the discharge port 113 can be controlled, and the gear shift speed during a downshift can be controlled.

[0030] [Upshift] FIG. 8 is a diagram showing the operating conditions of the upshift valve 85 and the downshift valve 90 during an upshift. As shown in FIG. 8, during an upshift, the supply of pilot pressure P4 by the electromagnetic valve 90a is cut off, and the spool 111 of the downshift valve 90 is held in a position moved in the direction of arrow B2 by spring force. In other words, the input port 112 and the discharge port 113 of the downshift valve 90 are blocked from each other, and the downshift valve 90 is held in a blocked state in which no hydraulic oil is discharged. Then, during an upshift, the pilot pressure P3 is increased by the electromagnetic valve 85a, causing the spool 101 of the upshift valve 85 to move in the direction of arrow A2 against the spring force. This allows the input port 102 and the output port 103 of the upshift valve 85 to communicate with each other, and hydraulic oil from the branch oil passage 83 can be supplied from the input port 102 to the output port 103, as shown by arrow FL2.

[0031] That is, as shown by arrow X2 in Figure 6, hydraulic oil is supplied from the upshift valve 85 to the primary oil chamber 32, and the primary pressure in the primary oil chamber 32 increases, causing the movable sheave 31 of the primary pulley 20 to move closer to the fixed sheave 30. Furthermore, the winding diameter of the drive chain 22 around the primary pulley 20 increases, causing the movable sheave 34 of the secondary pulley 21 to move away from the fixed sheave 33 so as to reduce the winding diameter of the drive chain 22 around the secondary pulley 21. In this way, hydraulic oil is supplied from the upshift valve 85 to the primary oil chamber 32, and the primary pressure in the primary oil chamber 32 is increased. This allows the winding diameter of the drive chain 22 around the primary pulley 20 to increase, and the gear ratio of the continuously variable transmission 13 to be changed to a higher gear (high side).

[0032] As shown in FIG. 8 , a tapered notch 109 is formed on the outer peripheral surface of a valve element 108 provided on the spool 101. That is, when the input port 102 and the output port 103 of the upshift valve 85 are to be communicated with each other, the input port 102 and the output port 103 are communicated with each other via the notch 109 of the spool 101. Because the notch 109, which functions as a communication flow path, is formed in a tapered shape, the cross-sectional area of ​​the flow path that communicates the input port 102 and the output port 103 can be adjusted by adjusting the stop position of the spool 101 according to the magnitude of the pilot pressure P3. That is, by adjusting the stop position of the spool 101 according to the pilot pressure P3, the flow rate of hydraulic oil flowing from the input port 102 to the output port 103 can be controlled, and the gear shift speed during an upshift can be controlled.

[0033] [Upshift valve wear] As described above, when upshifting continuously variable transmission 13, the flow rate of hydraulic oil flowing from input port 102 to output port 103 of upshift valve 85 is controlled by controlling pilot pressure P3 to adjust the stop position of spool 101. This makes it possible to control the speed at which continuously variable transmission 13 is upshifted, and to control continuously variable transmission 13 at an appropriate speed in accordance with engine output, etc. If we consider a case where an upshift is performed in step shift mode, the speed is significantly higher than in a continuously variable shift mode or the like in which the gear ratio is changed continuously, and this increases the load on upshift valve 85, which could result in wear on housing 100, etc.

[0034] That is, when an upshift is performed in step shift mode, the flow rate of hydraulic oil passing through the upshift valve 85 is high, and the spool 101 is pushed radially by the hydraulic oil flowing in at high speed from the input port 102. This causes the spool 101 to be pressed strongly against the inner circumferential surface of the housing 100, potentially causing wear on the housing 100 and the spool 101. If the housing 100 and the spool 101 are worn by an upshift in step shift mode, it becomes difficult to control the flow rate of hydraulic oil flowing from the input port 102 to the output port 103, making it difficult to accurately control the shift speed during an upshift. Therefore, the control system 50 executes valve wear determination control, described below, to determine the wear state of the upshift valve 85 and to execute a protection process to protect the upshift valve 85 from excessive wear.

[0035] [Valve wear determination control: Flowchart] The valve wear determination control executed by the control system 50 will now be described. Fig. 9 is a flowchart showing an example of the execution procedure for the valve wear determination control, and Fig. 10 is a diagram showing an example of an upper limit shift speed XS used in the valve wear determination control. Note that each step shown in the flowchart in Fig. 9 represents processing executed by one or more processors 70 that constitute the control system 50. The valve wear determination control shown in Fig. 9 is control that is executed by the control system 50 at predetermined intervals after the driver operates the start switch 66 and the control system 50, which is made up of the vehicle control unit 51 and the like, is started up.

[0036] As shown in Fig. 9, in step S10, it is determined whether or not an upshift has started in the step shift mode. If it is determined in step S10 that an upshift has started in the step shift mode, the process proceeds to step S11, where the gear at the start of the upshift (hereinafter referred to as the upshift gear) is read. In the following step S12, an upper limit shifting speed XS allowable during an upshift is set based on the upshift gear. That is, in step S12, an upper limit shifting speed XS allowable during an upshift is set based on the gear ratio of the continuously variable transmission 13 at the start of the upshift.

[0037] Here, as shown in Figure 10, the upper limit shifting speed XS is set to a higher value as the upshift gear becomes lower. For example, when the upshift gear is second gear (R2), that is, when upshifting from second gear to third gear (R2 → R3), "Xs2" is set as the upper limit shifting speed XS. Also, when the upshift gear is first gear (R1), that is, when upshifting from first gear to second gear (R1 → R2), "Xs1," which is higher than the aforementioned "Xs2," is set as the upper limit shifting speed XS. In this way, the lower the upshift gear is, the higher the upper limit shifting speed XS allowed during an upshift is set.

[0038] As described above, once the upper limit shifting speed XS is set in step S12, the process proceeds to step S13, where the shifting speed Ss of the continuously variable transmission 13 is calculated during the upshift. In step S13, the shifting speed Ss of the continuously variable transmission 13 is calculated based on a predetermined calculation period (e.g., 50 msec) and the amount of change in the gear ratio during this calculation period. Once the shifting speed Ss has been calculated in this manner, the process proceeds to step S14, where it is determined whether the shifting speed Ss exceeds the upper limit shifting speed XS. If it is determined in step S14 that the shifting speed Ss is equal to or less than the upper limit shifting speed XS, it means that the upshift valve 85 is functioning normally, and the process proceeds to step S15, where it is determined whether the upshift has been completed. If it is determined in step S15 that the upshift has not been completed, the process returns to step S13, where the shifting speed Ss during the upshift is calculated and it is determined whether the shifting speed Ss exceeds the upper limit shifting speed XS.

[0039] If it is determined in step S15 that the upshift is completed, that is, if the shift speed Ss of the continuously variable transmission 13 is equal to or less than the upper limit shift speed XS throughout the period from the start to the completion of the upshift, the process proceeds to step S16, where it is determined that the upshift valve 85 is in a normal state and the routine is terminated. In other words, a situation in which the shift speed Ss during the upshift is equal to or less than the upper limit shift speed XS means that the flow rate of hydraulic oil supplied from the upshift valve 85 to the primary oil chamber 32 is appropriate. In other words, a situation in which the shift speed Ss during the upshift is equal to or less than the upper limit shift speed XS means that the flow rate of hydraulic oil passing through the upshift valve 85 is appropriately reduced, and there is no excessive wear on the housing 100, the spool 101, etc. Therefore, if the shift speed Ss of the continuously variable transmission 13 is equal to or less than the upper limit shift speed XS throughout the period from the start to the completion of the upshift, the upshift valve 85 is determined to be in a normal state and the routine is terminated.

[0040] On the other hand, if it is determined in step S14 that the shift speed Ss during an upshift exceeds the upper limit shift speed XS, the process proceeds to step S17, where it is determined that the upshift valve 85 is in an abnormal state. In other words, a situation in which the shift speed Ss during an upshift exceeds the upper limit shift speed XS is a situation in which hydraulic oil is being supplied from the upshift valve 85 to the primary oil chamber 32 at an excessive flow rate. In other words, a situation in which the shift speed Ss during an upshift exceeds the upper limit shift speed XS is a situation in which the flow rate of hydraulic oil passing through the upshift valve 85 is not being appropriately throttled, and is considered to be a situation in which wear of the housing 100, spool 101, etc. is progressing. For this reason, if the shift speed Ss exceeds the upper limit shift speed XS, it is determined that wear of the housing 100, spool 101, etc. is progressing, and the upshift valve 85 is in an abnormal state.

[0041] If it is determined in step S17 that the upshift valve 85 is in an abnormal state, the process proceeds to step S18, where a process is executed to reduce the shift speed during an upshift as a protective process to protect the upshift valve 85. In this process of reducing the shift speed, a new target shift speed S2 that is lower than the target shift speed S1 that is set when the valve is normal is set as the target shift speed during an upshift. This makes it possible to reduce the shift speed when performing an upshift in the subsequent step shift mode, thereby reducing the load on the upshift valve 85 and suppressing the progression of wear. Note that when setting a new target shift speed S2 that is lower than the target shift speed S1, the target shift time from the start to the completion of the upshift may be set longer. In other words, the new target shift speed S2 that is lower than the target shift speed S1 may be set by setting a new target shift time that is longer than the target shift time corresponding to the target shift speed S1.

[0042] Furthermore, if it is determined in step S17 that the upshift valve 85 is in an abnormal state, the process proceeds to step S19, where a process is executed to notify the driver of the abnormal state of the upshift valve 85 as a protection process to protect the upshift valve 85. In step S19, for example, a warning light indicating an abnormality in the continuously variable transmission 13 is turned on, and a message urging the driver to take the vehicle to a maintenance shop or the like is displayed on the display 67. In this way, by urging the driver to inspect or repair the upshift valve 85, it is possible to avoid a breakdown of the upshift valve 85, and therefore it is possible to maintain the shift quality of the continuously variable transmission 13 appropriately over a long period of time.

[0043] [Valve wear detection control: timing chart] Fig. 11 is a timing chart showing an example of the execution status of valve wear determination control. Fig. 11 shows a situation in which an upshift is performed from first gear R1 to second gear R2 in step shift mode. In Fig. 11, the gear ratio α1 and the shift speed α2 shown by the solid lines correspond to each other, and the gear ratio β1 and the shift speed β2 shown by the dashed lines correspond to each other.

[0044] As shown at time t1 in Figure 11, when an upshift in step shift mode is initiated, an upper limit shift speed Xs1 allowed during the upshift is set based on the gear R1 at the start of the upshift. Then, if the shift speed α2 is equal to or less than the upper limit shift speed Xs1 as shown by the solid line over the period from time t1 to time t2, that is, the period from the start to the completion of the upshift, it is determined that the upshift valve 85 is in a normal state. In other words, when the shift speed α2 is equal to or less than the upper limit shift speed Xs1, the flow rate of hydraulic oil is sufficiently restricted by the upshift valve 85, and therefore the upshift valve 85 is determined to be in a normal state. Note that the shift speed α2 during the upshift is controlled toward the target shift speed S1 that is set when the valve is normal.

[0045] On the other hand, as shown by the dashed line, when the shift speed β2 during an upshift exceeds the upper limit shift speed Xs1 (symbol a10), the upshift valve 85 is not sufficiently throttling the flow rate of hydraulic oil, and so the upshift valve 85 is determined to be in an abnormal state (symbol b10). When the upshift valve 85 is determined to be in an abnormal state, a new target shift speed S2 lower than the previous target shift speed S1 is set as the target shift speed for the upshift. This makes it possible to lower the shift speed during subsequent upshifts when the upshift valve 85 is determined to be in an abnormal state, thereby reducing the load on the upshift valve 85 and suppressing the progression of wear. Note that the target shift speeds S1 and S2 may be set differently for each gear, or a common target shift speed S1 and S2 may be set for all gears.

[0046] As described above, the control system 50 sets the upper limit shifting speed XS based on the upshift gear when starting an upshift in step shift mode. Furthermore, if the shifting speed Ss of the continuously variable transmission 13 exceeds the upper limit shifting speed XS during an upshift in step shift mode, the control system 50 determines that the upshift valve 85 is in an abnormal state. This makes it possible to appropriately determine whether an abnormality is caused by wear of the upshift valve 85. Furthermore, the control system 50 does not use a fixed value as the upper limit shifting speed XS, but sets the upper limit shifting speed XS based on the gear ratio of the continuously variable transmission 13. In other words, the control system 50 sets the upper limit shifting speed XS higher the lower the upshift gear. In this way, by varying the upper limit shifting speed XS in accordance with the gear ratio of the continuously variable transmission 13, it is possible to more appropriately determine whether the upshift valve 85 is in an abnormal state.

[0047] Here, a situation in which the upshift gear is a low gear means that a large torque capacity is required of the continuously variable transmission 13, and the line pressure PL of the hydraulic circuit is adjusted high. In other words, even in a situation in which the same wear occurs in the upshift valve 85, when the upshift gear is a low gear, the line pressure PL is higher than when the upshift gear is a high gear, and therefore the flow rate of hydraulic oil passing through the upshift valve 85 is likely to be greater. In other words, when the upshift gear is a low gear, the shift speed Ss of the continuously variable transmission 13 is likely to be higher than when the upshift gear is a high gear.

[0048] For this reason, if a fixed value was used as the upper limit shifting speed XS, it was difficult to appropriately set the upper limit shifting speed XS. That is, if the value of the upper limit shifting speed XS was set to correspond to a high gear, when the upshift gear was a low gear, the shifting speed Ss would easily exceed the upper limit shifting speed XS, which could result in an erroneous determination that the upshift valve 85 was abnormal. On the other hand, if the value of the upper limit shifting speed XS was set to correspond to a low gear, when the upshift gear was a high gear, the shifting speed Ss would not easily exceed the upper limit shifting speed XS, which could result in an erroneous determination that the upshift valve 85 was normal. In contrast, by changing the upper limit shifting speed XS in accordance with the gear ratio of the continuously variable transmission 13, it is possible to appropriately set the upper limit shifting speed XS in accordance with the upshift gear, which could more appropriately determine whether the upshift valve 85 was abnormal.

[0049] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and scope of the present invention. In the above description, the control system 50 is configured by a plurality of control units 38, 44, and 51, but this is not limiting. For example, the control system 50 may be configured by a single control unit. Furthermore, in the above description, the oil pump 37 is driven by the engine 12, but this is not limiting, and the oil pump 37 may be driven by an electric motor.

[0050] In the above description, the upshift valve 85 that controls the supply of hydraulic oil and the downshift valve 90 that controls the discharge of hydraulic oil are connected to the primary oil chamber 32 of the primary pulley 20, but this is not limiting. That is, a single control valve that controls the supply and discharge of hydraulic oil may be connected to the primary oil chamber 32 of the primary pulley 20. Also, in the example shown in FIG. 9, the protective process to protect the upshift valve 85 involves executing a process to reduce the shift speed during upshifts and notifying the driver of an abnormal state of the upshift valve 85, but this is not limiting. For example, the protective process to protect the upshift valve 85 may involve only a process to reduce the shift speed during upshifts, or only a process to notify the driver of an abnormal state of the upshift valve 85.

[0051] In the above description, the step shift mode in which the gear ratio is controlled in steps is used as the shift mode of the continuously variable transmission 13. However, other shift modes may be used in addition to the step shift mode. For example, the continuously variable transmission 13 may use a continuously variable transmission mode in which the gear ratio is continuously controlled. When executing this continuously variable transmission mode, the control system 50 references a predetermined shift characteristic map based on the accelerator pedal position and vehicle speed, and sets the target gear ratio to be used in the continuously variable transmission mode. For example, when the accelerator pedal is depressed while driving, the target primary rotation speed is increased in response to an increasing accelerator pedal position, and the target gear ratio of the continuously variable transmission 13 is continuously controlled toward a lower rotation speed. On the other hand, when the accelerator pedal is released while driving, the target primary rotation speed is decreased in response to a decreasing accelerator pedal position, and the target gear ratio of the continuously variable transmission 13 is continuously controlled toward a higher rotation speed. [Explanation of symbols]

[0052] 10 Vehicle control device 11 vehicles 13 Continuously variable transmission 20 Primary pulley 21 Secondary pulley 32 Primary oil chamber 35 Secondary oil chamber 37 Oil pump 50 Control System 70 processors 71 memory 85 Upshift valve (control valve) 88 Oil road XS upper limit shift speed Ss Shifting speed S1 Target shift speed S2 Target shift speed

Claims

1. A vehicle control device provided in a vehicle, a continuously variable transmission having a primary pulley having a primary oil chamber and a secondary pulley having a secondary oil chamber; an oil pump connected to the primary oil chamber and the secondary oil chamber, and configured to pump hydraulic oil to the primary oil chamber and the secondary oil chamber; a control valve provided in an oil passage connecting the oil pump and the primary oil chamber, the control valve supplying hydraulic oil to the primary oil chamber when the continuously variable transmission is upshifting; a control system including a processor and a memory communicatively connected to each other, the control system controlling the continuously variable transmission via the control valve; and the control system sets an upper limit shift speed higher as the gear ratio of the continuously variable transmission increases at the start of an upshift in a step shift mode in which the gear ratio of the continuously variable transmission is controlled in a stepwise manner, the control system determines that the control valve is in an abnormal state when the shift speed of the continuously variable transmission exceeds the upper limit shift speed during an upshift in the step shift mode. Vehicle control device.

2. 2. The vehicle control device according to claim 1, When the control system determines that the control valve is in an abnormal state, it sets the target shift speed for upshifting to a new target shift speed that is lower than the previous target shift speed. Vehicle control device.

3. 3. The vehicle control device according to claim 1, When the control system determines that the control valve is in an abnormal state, the control system notifies a driver of the abnormal state of the control valve. Vehicle control device.

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