Control device for vehicle

Abstract

To provide a control device for a vehicle, which can suppress an engaging delay of an engagement device when switching to a drive position for the first time after an engine is started.SOLUTION: After an engine is started and before a shift position is switched from a non-traveling position to a traveling position for the first time, a selector valve is temporarily switched to a first state in which a base pressure is supplied to an engagement pressure control valve. As a result, air accumulated in an oil passage for supplying the base hydraulic pressure of an engagement device to the engagement pressure control valve, when the engine is stopped, is discharged by switching to the first state, so that a decrease in hydraulic pressure and base pressure can be suppressed when the engagement device is engaged for the first time. Therefore, when the traveling position is switched for the first time after the engine is started, a delay in engagement of the engagement device can be suppressed. In addition, since the engagement pressure control valve is controlled so as to maintain a disengaged state of the engagement device before first switching to the traveling position, the non-traveling position of a power transmission device is maintained.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle equipped with a power transmission device that transmits engine power to drive wheels via an engagement device. [Background technology]

[0002] There is a well-known control device for a vehicle that includes an engine and a power transmission device that transmits the power of the engine to driving wheels via an engagement device. For example, there is a vehicle control device described in Patent Document 1. Patent Document 1 discloses that when the shift position of the power transmission device is set to a non-driving position in which the power transmission in the power transmission device is cut off, the hydraulic pressure of the engagement device is released to disengage the engagement device, and a neutral state is maintained. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-84160 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the engine is stopped, the oil pressure of the engagement device cannot be generated, and oil leaks out from the hydraulic control circuit including the engagement pressure control valve that outputs the hydraulic pressure of the engagement device. On the other hand, when the shift position is a non-driving position, there may be an oil passage to which oil is not supplied (filled) even after the engine is started in the hydraulic control circuit, for example, an oil passage that supplies the original pressure to the engagement pressure control valve. In this case, when the shift position is switched from the non-driving position to a driving position in which power transmission in the power transmission device is possible, the supply of oil may be delayed and the original pressure may drop. If the original pressure drops below a predetermined value, there is a risk of an engagement delay in the engagement device. This phenomenon is likely to occur when switching to the driving position for the first time after the engine is started from a long engine stop state.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a vehicle control device that can suppress engagement delay of an engagement device when switching to a driving position for the first time after starting the engine. [Means for solving the problem]

[0006] The gist of a first invention is a control device for a vehicle including (a) an engine and a power transmission device that transmits power of the engine to driving wheels via an engagement device, wherein (b) the vehicle further includes an engagement pressure control valve that outputs, to the engagement device, an engagement pressure that is adjusted using hydraulic pressure generated in an operating state of the engine as a base pressure and switches the engagement device between a disengaged state and an engaged state, and a switching valve that is switchable between a first state in which the base pressure is supplied to the engagement pressure control valve and a second state in which the supply of the base pressure to the engagement pressure control valve is cut off, and (c) a control device for a vehicle including a power transmission device that controls a shift position of the power transmission device to be shifted by a switching valve that is switched between a first state in which the base pressure is supplied to the engagement pressure control valve and a second state in which the supply of the base pressure to the engagement pressure control valve is cut off, When the shift position is a driving position in which power transmission in the power transmission device is possible, the switching valve is switched to the first state, while when the shift position is a non-driving position in which power transmission in the power transmission device is cut off, the switching valve is switched to the second state; (d) after the engine is started and before the shift position is switched for the first time from the non-driving position to the driving position, the switching valve is temporarily switched to the first state and the engagement pressure control valve is controlled so that the engagement device is maintained in a released state. Effect of the Invention

[0007] According to the first aspect of the present invention, after the engine is started and before the shift position is switched from the non-driving position to the driving position for the first time, the switching valve is temporarily switched to the first state in which the base pressure is supplied to the engagement pressure control valve. As a result, air accumulated in the oil passage that supplies the base pressure of the hydraulic pressure of the engagement device to the engagement pressure control valve when the engine is stopped is discharged by switching to the first state, and a decrease in the hydraulic pressure and base pressure at the time of the initial engagement of the engagement device can be suppressed. Therefore, a delay in engagement of the engagement device can be suppressed at the time of the initial switching to the driving position after the engine is started. In addition, since the engagement pressure control valve is controlled so that the release state of the engagement device is maintained before the initial switching to the driving position, the non-driving position of the power transmission device is maintained. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is also a diagram illustrating main parts of control functions and a control system for various controls in the vehicle. [Diagram 2] FIG. 2 is a diagram showing a part of a hydraulic control circuit. [Diagram 3] 1 is a flowchart illustrating the main control operations of an electronic control device, and is a flowchart illustrating the control operations for suppressing an engagement delay of an engagement device when switching to a driving range for the first time after the engine is started. [Figure 4] FIG. 13 is a diagram showing another embodiment to which the present invention is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. EXAMPLES

[0010] Fig. 1 is a diagram illustrating a schematic configuration of a vehicle 10 to which the present invention is applied, and is also a diagram illustrating the main parts of the control functions and control system for various controls in the vehicle 10. In Fig. 1, the vehicle 10 is equipped with an engine 12 that functions as a power source, drive wheels 14, and a power transmission device 16 provided in a power transmission path between the engine 12 and the drive wheels 14. The engine 12 is a known internal combustion engine, and is controlled by an electronic control device 90, which will be described later, controlling an engine control device 50 provided in the vehicle 10.

[0011] The power transmission device 16 includes, within a case 18, a torque converter 20 having a lock-up clutch LU, an input shaft 22, a continuously variable transmission mechanism 24, a forward / reverse switching device 26, a gear mechanism 28, an output shaft 30, a counter shaft 32, a reduction gear device 34, a gear 36, a differential gear 38, etc. The power transmission device 16 also includes left and right axles 40 connected to the differential gear 38, etc.

[0012] The power transmission device 16 has a first power transmission path PT1 and a second power transmission path PT2 arranged in parallel between the input shaft 22 and the output shaft 30, and capable of transmitting the power of the engine 12 from the input shaft 22 to the output shaft 30, respectively.

[0013] In the power transmission device 16, the power transmission path that transmits the power of the engine 12 is switched between a first power transmission path PT1 and a second power transmission path PT2 depending on the running state of the vehicle 10. The power transmission device 16 includes a mesh clutch D1, a first clutch C1, a first brake B1, and a second clutch C2 for selectively forming the first power transmission path PT1 and the second power transmission path PT2. The mesh clutch D1 and the first clutch C1 or the first brake B1 are both engagement devices that form the first power transmission path PT1 when engaged. The second clutch C2 is an engagement device that forms the second power transmission path PT2 when engaged.

[0014] The forward / reverse switching device 26 includes a planetary gear set 26p having a carrier 26c, a sun gear 26s, and a ring gear 26r, a first clutch C1, and a first brake B1. The carrier 26c is connected to the input shaft 22. The ring gear 26r is selectively connected to the case 18 via the first brake B1. The sun gear 26s is connected to a small-diameter gear 60 that is provided around the input shaft 22 so as to be rotatable relative to the input shaft 22 and coaxially therewith. The carrier 26c and the sun gear 26s are selectively connected to each other via the first clutch C1.

[0015] Both the first clutch C1 and the first brake B1 are known hydraulic wet friction engagement devices. The first clutch C1 is an engagement device for forward travel, and the first brake B1 is an engagement device for reverse travel. The first clutch C1 and the first brake B1 each have their control states (released state, slip state, engaged state) switched by hydraulic pressure supplied from a hydraulic control circuit 52 provided in the vehicle 10, which is controlled by an electronic control device 90 described later.

[0016] The gear mechanism 28 includes a small diameter gear 60, a gear mechanism counter shaft 62, and a large diameter gear 64 that is provided around the gear mechanism counter shaft 62 coaxially and non-rotatable relative to the gear mechanism counter shaft 62 and meshes with the small diameter gear 60. The gear mechanism 28 also includes an idler gear 66 that is provided around the gear mechanism counter shaft 62 coaxially and non-rotatable relative to the gear mechanism counter shaft 62, and an output gear 68 that is provided around the output shaft 30 coaxially and non-rotatable relative to the output shaft 30 and meshes with the idler gear 66.

[0017] The dog clutch D1 is provided around the gear mechanism counter shaft 62 between the large diameter gear 64 and the idler gear 66, and selectively connects and disconnects the power transmission path therebetween. The dog clutch D1 is a known dog clutch whose control state (released state, engaged state) is switched by the operation of a hydraulic actuator 54 provided in the vehicle 10. The dog clutch D1 is equipped with a known synchromesh mechanism S1. The hydraulic actuator 54 is operated by hydraulic pressure supplied from the hydraulic control circuit 52.

[0018] The continuously variable transmission mechanism 24 includes a primary shaft 70 provided coaxially with the input shaft 22 and connected to the input shaft 22, a primary pulley 72 with a variable effective diameter connected to the primary shaft 70, a secondary shaft 74 provided coaxially with the output shaft 30, a secondary pulley 76 with a variable effective diameter connected to the secondary shaft 74, and a transmission belt 78 wound around the pulleys 72, 76. The continuously variable transmission mechanism 24 is a known belt-type continuously variable transmission.

[0019] The output shaft 30 is disposed coaxially with the secondary shaft 74 so as to be rotatable relative to the secondary shaft 74. The second clutch C2 is provided in a power transmission path between the secondary pulley 76 and the output shaft 30. The second clutch C2 is a known hydraulic wet friction engagement device. The second clutch C2 has its control states (released state, slip state, engaged state) switched by hydraulic pressure supplied from a hydraulic control circuit 52.

[0020] In the power transmission device 16, the speed ratio in the first power transmission path PT1 is set to a value greater than the lowest speed ratio of the continuously variable transmission mechanism 24, which is the maximum speed ratio in the second power transmission path PT2. The gear driving mode in which the first power transmission path PT1 is formed in the power transmission device 16 is selected in a relatively low vehicle speed range including when the vehicle is stopped. The belt driving mode in which the second power transmission path PT2 is formed in the power transmission device 16 is selected in a relatively high vehicle speed range including a medium vehicle speed range.

[0021] The vehicle 10 includes a mechanical oil pump 56. The oil pump 56 is connected to a pump impeller of the torque converter 20, and is driven to rotate by the engine 12 to discharge hydraulic oil OIL that is supplied to the hydraulic control circuit 52. The hydraulic control circuit 52 supplies C1 pressure Pc1, B1 pressure Pb1, C2 pressure Pc2, and S1 pressure Ps1, which are hydraulic pressures for switching the control states of the first clutch C1, the first brake B1, the second clutch C2, and the dog clutch D1, based on the supplied hydraulic oil OIL. The hydraulic pressure for switching the control state of the dog clutch D1 is expressed as S1 pressure Ps1 because it operates the synchromesh mechanism S1.

[0022] The vehicle 10 is equipped with a shift device 58 having a shift operation member operated by a driver to one of a plurality of operation positions POSop. The shift device 58 is a shift switching device for switching the shift position (including the shift range Rsh) of the power transmission device 16. The operation position POSop is a signal representing a selected state of the power transmission state in the power transmission device 16, and includes, for example, P, R, N, and D operation positions. The shift range Rsh represents the power transmission state of the power transmission device 16, and includes, for example, P, R, N, and D ranges. The P (parking) operation position represents a selected state of the P range of the power transmission device 16, in which the power transmission device 16 is in a neutral state and the output shaft 30 is mechanically fixed so as not to rotate. The neutral state of the power transmission device 16 is a state in which neither the first power transmission path PT1 nor the second power transmission path PT2 is formed, and is realized, for example, by disengaging the first clutch C1, the first brake B1, and the second clutch C2. The R (reverse running) operating position represents the selected state of the R range of the power transmission device 16 that enables reverse running in the gear running mode. The N (neutral) operating position represents the selected state of the N range of the power transmission device 16 in which the power transmission device 16 is in a neutral state. The D (forward running) operating position represents the selected state of the D range of the power transmission device 16 that enables forward running in the gear running mode, or enables forward running by executing automatic shift control of the continuously variable transmission mechanism 24 in the belt running mode. The D and R ranges are running positions (also the same as running ranges) in which power transmission in the power transmission device 16 is enabled. The P and N ranges are non-running positions (also the same as non-running ranges) in which power transmission in the power transmission device 16 is cut off.

[0023] Fig. 2 is a diagram showing a part of the hydraulic control circuit 52. In Fig. 2, the hydraulic control circuit 52 includes a first changeover valve 80, a second changeover valve 82, a third changeover valve 84, and a fourth changeover valve 86 for switching oil paths, an ON-OFF solenoid valve SC1, an ON-OFF solenoid valve SC2, and an ON-OFF solenoid valve SC3 for valve operation, and a lock-up hydraulic control valve SLU, a first hydraulic control valve SL1, a second hydraulic control valve SL2, and a garage hydraulic control valve SLG for hydraulic control. The hydraulic control valves SLU, SL1, SL2, and SLG are, for example, linear solenoid valves.

[0024] The first switching valve 80 is electrically switched by an ON-OFF solenoid valve SC1 between a first state (see solid line) in which the line pressure PL is output as a D-range pressure PD and a second state (see dashed line) in which the line pressure PL is output as an R-range pressure PR. The line pressure PL is a hydraulic pressure adjusted by a regulator valve (not shown) based on the hydraulic oil OIL discharged by the oil pump 56, and is a hydraulic pressure generated in the operating state of the engine 12. The first hydraulic control valve SL1 supplies the C1 pressure Pc1, which is the line pressure PL or the D-range pressure PD, to the first clutch C1. The first hydraulic control valve SL1 is an engagement pressure control valve that outputs the C1 pressure Pc1, which is an engagement pressure adjusted to switch the first clutch C1 between a released state and an engaged state, to the first clutch C1 using the line pressure PL as a base pressure. The other hydraulic control valves SLU, SL2, and SLG are similar. The first switching valve 80 is a switching valve that can be switched between a first state in which the line pressure PL is supplied to the first hydraulic control valve SL1 as the D-range pressure PD, and a second state in which the supply of the line pressure PL as the D-range pressure PD to the first hydraulic control valve SL1 is cut off.

[0025] 1, the vehicle 10 is equipped with an electronic control device 90 as a controller including a control device of the vehicle 10. The electronic control device 90 is supplied with various signals (e.g., operation position POSop, etc.) based on detection values ​​by various sensors (e.g., operation position sensor 100, etc.) provided in the vehicle 10. In addition, the electronic control device 90 outputs various command signals (e.g., engine control command signal Se, SC1 control command signal Ssc1, SL1 control command signal Ssl1, etc.) to each device (e.g., engine control device 50, hydraulic control circuit 52, etc.) provided in the vehicle 10.

[0026] The electronic control device 90 includes a hydraulic switching unit 92. When the shift range Rsh of the power transmission device 16 is set to a driving range (particularly the D range), the hydraulic switching unit 92 outputs an SC1 control command signal Ssc1 that turns on the ON-OFF solenoid valve SC1 so as to switch the first changeover valve 80 to a first state. On the other hand, when the shift range Rsh is set to a non-driving range (P, N range), the hydraulic switching unit 92 outputs an SC1 control command signal Ssc1 that turns off the ON-OFF solenoid valve SC1 so as to switch the first changeover valve 80 to a second state. The hydraulic control circuit 52 does not switch the shift range Rsh by a known manual valve linked to the shift device 58, but employs a manual valveless control system that switches the shift range Rsh by hydraulic switching using the ON-OFF solenoid valve SC1.

[0027] Incidentally, in the hydraulic control circuit 52, when the engine 12 is left stopped for a long period of time, the hydraulic oil OIL leaks out from inside. On the other hand, in the hydraulic control circuit 52, there are oil passages, for example, D-range pressure oil passages 88 and 89, to which the hydraulic oil OIL is not supplied (filled) when the range is not in the driving range even after the engine is started. Therefore, when the range is switched to the driving range (especially the D range), the supply of the hydraulic oil OIL to the D-range pressure oil passages 88 and 89 may be delayed, causing the line pressure PL to drop. If the line pressure PL drops below a predetermined value, the output hydraulic pressure of the ON-OFF solenoid valve may drop, causing the switching valve to be erroneously switched, and for example, the mesh clutch D1 may be disengaged, making it impossible to form the driving range.

[0028] Therefore, the hydraulic switching unit 92 switches the first changeover valve 80 to the first state when in the non-driving range after the engine is started, and controls the first hydraulic control valve SL1 so that the release state of the first clutch C1 is maintained. Moreover, the hydraulic switching unit 92 performs this control only until the first switching to the driving range (particularly the D range) after the engine is started. The mesh clutch D1 may be in an engaged state in advance when in the non-driving range. The hydraulic switching unit 92 performs this control after the engine is started, and before the mesh clutch D1 is in an engaged state. If this control is performed after waiting for the switching of the mesh clutch D1 to the engaged state, there is a possibility that an event will occur in which the mesh clutch D1 is in a released state due to a pressure drop in the line pressure PL. If it is performed before the operation to the D operating position, there will be no problem if it is re-engaged, but if the operation to the D operating position is performed in a short time after the engine is started, there is a risk that a problematic event cannot be avoided. For this reason, it is more effective to carry out this control before the dog clutch D1 is brought into the engaged state.

[0029] In this way, after the engine 12 has started and before the shift range Rsh has been switched for the first time from the non-driving position to the driving position, the hydraulic pressure switching unit 92 temporarily switches the first changeover valve 80 to the first state and controls the first hydraulic control valve SL1 so that the first clutch C1 is maintained in the released state. Note that, in order to supply the line pressure PL also to the D-range pressure oil passage 89, the third changeover valve 84 functioning as a changeover valve must also be switched to the first state.

[0030] FIG. 3 is a flowchart illustrating the main control operations of the electronic control device 90, and is a flowchart illustrating the control operations for suppressing an engagement delay of the engagement device when switching to the driving range for the first time after the engine is started, and is executed, for example, repeatedly.

[0031] In FIG. 3, each step of the flow chart corresponds to the function of the hydraulic switching unit 92. In step (hereinafter, step will be omitted) S10, it is determined whether or not a condition is satisfied. The condition is, for example, after the engine is started and before the first switching to the driving range, the line pressure PL is a predetermined value or more, and the dog clutch D1 is not yet engaged. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is positive, in S20, the ON-OFF solenoid valve SC1 is turned on for a predetermined time. That is, the same state as the D range (SC1=ON, SC2=OFF, SC3=ON) is set. In addition, the first hydraulic control valve SL1, the second hydraulic control valve SL2, and the garage hydraulic control valve SLG are turned off, and the output hydraulic pressures of each are set to zero.

[0032] As described above, according to this embodiment, after the engine is started and before the first switching to the driving range, the first switching valve 80 and the third switching valve 84 are temporarily switched to the first state. As a result, air accumulated in the D-range pressure oil passages 88, 89, etc., which supply the line pressure PL to the first hydraulic control valve SL1 when the engine 12 is stopped, is discharged by switching to the first state, and the decrease in the C1 pressure Pc1 and the line pressure PL at the first engagement of the first clutch C1 can be suppressed. Therefore, at the first switching to the driving position after the engine is started, the engagement delay of the first clutch C1 can be suppressed. In addition, before the first switching to the driving position, the first hydraulic control valve SL1 is controlled so that the release state of the first clutch C1 is maintained, so that the non-driving position of the power transmission device 16 is maintained.

[0033] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0034] For example, the present invention can be applied to control that is performed before the initial switching to the R range. In this case, the target switching valve is the second switching valve 82, and the target engagement pressure control valve is the hydraulic control valve SLG.

[0035] The present invention can also be applied to another embodiment shown in Fig. 4. Fig. 4(a) corresponds to Fig. 2, and Fig. 4(b) corresponds to Fig. 3.

[0036] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0037] 10: vehicle 12: engine 14: drive wheels 16: power transmission device 80: first changeover valve (changeover valve) 82: second changeover valve (changeover valve) 84: third changeover valve (changeover valve) 90: electronic control device (control device) B1: first brake (engagement device) C1: first clutch (engagement device) SL1, SL2, SLG: hydraulic control valve (engagement pressure control valve) PL: line pressure (hydraulic pressure, source pressure)

Claims

[Claim 1] A control device for a vehicle including an engine and a power transmission device that transmits power of the engine to drive wheels via an engagement device, The vehicle further includes an engagement pressure control valve that outputs, to the engagement device, an engagement pressure that is adjusted by using hydraulic pressure generated in an operating state of the engine as an original pressure and that switches the engagement device between a disengaged state and an engaged state, and a switching valve that is switched between a first state in which the original pressure is supplied to the engagement pressure control valve and a second state in which supply of the original pressure to the engagement pressure control valve is cut off, When a shift position of the power transmission device is set to a traveling position in which power transmission in the power transmission device is enabled, the switching valve is switched to the first state, whereas when the shift position is set to a non-traveling position in which power transmission in the power transmission device is interrupted, the switching valve is switched to the second state, A vehicle control device characterized in that, after the engine is started and before the shift position is changed for the first time from the non-driving position to the driving position, the switching valve is temporarily changed to the first state and the engagement pressure control valve is controlled so that the engagement device is maintained in a released state.

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