Vehicle control device

Abstract

To provide a vehicle control device suppressing occurrence of abnormal vibration.SOLUTION: Control of a WSC oil pressure PR is executed so that a period when the WSC oil pressure PR is a piston stroke end attainment pressure Pe or lower and also a rotor movement start pressure Ps or higher, becomes a prescribed thrust application time Ta or longer which is equal to or longer than a period having a conventional rotor movement start pressure Ps or higher when power transmission is performed in a slip state of a clutch WSC. Thereby, an inclination of a rotor support member MGrt linked with the clutch WSC is corrected by the WSC oil pressure PR, and abnormal vibration of a vehicle 10 caused when a separator 50 and a friction material 52 incline and get in touch with each other is suppressed.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a vehicle control device that suppresses the occurrence of abnormal vibration of a clutch.

Background Art

[0002] In order to suppress the occurrence of abnormal vibration when the clutch is switched from the released state to the engaged state, a technique for reducing the undulation of the surface of the friction material in the clutch is known. For example, the one described in Patent Document 1 is such a technique. As described in Patent Document 1, if the surface of the friction material is smooth, the occurrence of abnormal vibration such as judder is suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a vehicle including a first clutch that disconnects and connects power transmission between an internal combustion engine and an electric motor, a second clutch that disconnects and connects power transmission between the electric motor and a pair of drive wheels, and a rotor support member of the electric motor that houses the second clutch, even if the surface of the friction material of the second clutch is smooth, when there is an inclination in the rotor support member, when the second clutch performs power transmission in a slip state, the separator, which is an input-side component of the second clutch, and the friction material, which is an output-side component, may come into contact while being inclined, resulting in the occurrence of the abnormal vibration.

[0005] The present invention has been made against the background of the above circumstances, and an object thereof is to provide a vehicle control device capable of suppressing the occurrence of abnormal vibration.

Means for Solving the Problems

[0006] The gist of the present invention is a control device for a vehicle, comprising: (a) a first clutch for disconnecting and connecting power transmission between an internal combustion engine and an electric motor; a second clutch for disconnecting and connecting power transmission between the electric motor and a pair of drive wheels; and a rotor support member of the electric motor that houses the second clutch, wherein (b) when the second clutch performs power transmission in a slip state, the engagement hydraulic pressure of the second clutch is controlled such that the period during which the engagement hydraulic pressure is equal to or lower than the hydraulic pressure for causing the piston of the second clutch to reach the stroke end position and equal to or higher than the hydraulic pressure for starting to move the rotor support member in the thrust direction is equal to or longer than a predetermined time.

Effect of the Invention

[0007] According to the control device for a vehicle of the present invention, when the second clutch performs power transmission in a slip state, the engagement hydraulic pressure of the second clutch is controlled such that the period during which the engagement hydraulic pressure is equal to or lower than the hydraulic pressure for causing the piston of the second clutch to reach the stroke end position and equal to or higher than the hydraulic pressure for starting to move the rotor support member in the thrust direction is equal to or longer than a predetermined time. As a result, the time from the start pressure of the rotor support member in the thrust direction to the piston stroke end pressure is lengthened, and the movement of the rotor support member in the thrust direction can be utilized. Therefore, the inclination of the rotor support member of the electric motor that houses the second clutch is corrected by the engagement hydraulic pressure of the second clutch, and abnormal vibration of the vehicle that occurs when the separator, which is an input-side component of the second clutch, and the friction material, which is an output-side component of the second clutch, are inclined and come into contact is suppressed.

[0008] Preferably, the hydraulic pressure in the engagement control of the second clutch (hereinafter referred to as inclination correction control) performed in the previous item is preferably changed according to the oil temperature. For example, when the oil temperature is high, the viscosity of the oil is low, the hydraulic pressure can be lowered, and the fuel consumption can be improved by not applying an excessive hydraulic pressure.

[0009] Preferably, the inclination correction control is not performed except for gear ratios where the output torque fluctuation is high, that is, where the vibration transmission sensitivity in the vehicle is a problem. Therefore, at gear ratios with low output torque fluctuation, the inclination correction control is not performed, and since the torque transmission reaction is accelerated, drivability is improved.

[0010] Preferably, since the vibration transmission sensitivity and the force applied due to the specifications of the second clutch differ for each vehicle, by not performing the inclination correction control on vehicles with low output torque fluctuation, the torque transmission reaction is accelerated and drivability is improved. The determination of whether the output torque fluctuation is low is made, for example, based on whether the fluctuation range of the output rotational speed detected by an output rotational speed sensor is equal to or less than a predetermined threshold value. The fluctuation range is calculated, for example, by extracting the primary component through the execution of a sequential fast Fourier transform and band-pass filter processing on the output rotational speed. Also, the determination may be made, for example, based on whether the acceleration fluctuation range measured by an acceleration sensor provided in the vehicle is equal to or less than a predetermined threshold value.

[0011] Preferably, since there is a risk that the reaction of power transmission to the driver's driving force request will be slower than before, the inclination correction control is started at the time of starting the engine (internal combustion engine), which is the stage before the power transmission of the second clutch. Thereby, it is possible to quickly respond to the driver's driving force request and drivability is improved.

[0012] Preferably, when implementing the inclination correction control in a four-wheel drive vehicle equipped with two power sources that independently drive the front and rear wheels respectively, the driving torque from the other power source is increased. Thereby, the torque response delay due to the implementation of the inclination correction control is interpolated by the driving torque from the other power source, improving the torque responsiveness.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment

[0015] In FIG. 1, the vehicle 10 is a four-wheel drive hybrid vehicle having two power sources. The first power source is a front drive unit 16 including an engine 12 and a trunk axle 18 incorporating a motor MG1, and power is transmitted to the front wheels 14, which are a pair of drive wheels, via a front drive shaft 26. The second power source is a rear drive unit 32 incorporating a motor MG2, and power is transmitted to a pair of rear wheels 34 via a rear drive shaft 36. Further, the vehicle 10 is provided with a battery 46 and a DCDC converter 48 for transforming the voltage of the battery 46 as power sources for operating the motor MG1 and the motor MG2.

[0016] The engine 12 is a well-known internal combustion engine and corresponds to the "internal combustion engine" in the present invention.

[0017] The trunk axle 18 includes, in order from the side connected to the engine 12 via the crankshaft 20, a clutch K0, a motor MG1, a rotor support member MGrt, a clutch WSC, an input shaft 28, an automatic transmission 22, an output shaft 30, a front differential 24, etc., and also includes a hydraulic control circuit 40 and an inverter 42, which are well-known configurations.

[0018] Clutch K0 is an engagement device that disconnects and connects power transmission between the engine 12 and the motor MG1, and clutch WSC is an engagement device that disconnects and connects power transmission between the motor MG1 and the automatic transmission 22, and each is, for example, a wet multi-plate hydraulic friction engagement device. The motor MG1 is, for example, a so-called motor generator, and the electric power (voltage) transformed from the battery 46 via the DCDC converter 48 is rotationally driven via the inverter 42. The rotor support member MGrt supports the rotor RT and is a bottomed cylindrical component that houses the clutch WSC, and is rotatably supported by the case CA via a pair of bearings LB and HB. Clutch K0 and clutch WSC respectively correspond to the "first clutch" and "second clutch" in the present invention.

[0019] The hydraulic control circuit 40 supplies the necessary hydraulic oil OIL to each part in the trunk axle 18, using the hydraulic pressure of the hydraulic oil OIL discharged from, for example, an oil pump (not shown) as the original pressure.

[0020] The rear drive unit 32 includes a motor MG2, an inverter 44, a speed reduction mechanism 38 that incorporates a rear differential, etc. The motor MG2 is, for example, a so-called motor generator, and the electric power (voltage) of the battery 46 is rotationally driven via the inverter 44. The power of the motor MG2 is transmitted to the rear wheels 34 via the speed reduction mechanism 38 and the rear drive shaft 36.

[0021] The electronic control unit 90 executes various controls for the vehicle 10. Various signals (for example, the output rotational speed Nout of the output shaft 30 corresponding to the vehicle speed V, the longitudinal acceleration Gx and the lateral acceleration Gy of the vehicle 10, the accelerator opening θacc representing the magnitude of the driver's accelerator operation, the yaw rate Ryaw which is the rotational angular velocity around the vertical axis of the vehicle 10, etc.) based on the detection values by various sensors (for example, the output rotational speed sensor 74, the G sensor 76, the accelerator opening sensor 78, the yaw rate sensor 80, etc.) are input to the electronic control unit 90. Further, various control signals (for example, the engine control signal Se, the shift control signal Sat of the automatic transmission 22, the K0 control signal Sk0 of the clutch K0, the WSC control signal Swsc of the clutch WSC, the MG1 control signal Sm1 of the motor MG1, the MG2 control signal Sm2 of the motor MG2, etc.) are output from the electronic control unit 90 to each device (for example, the engine 12, the hydraulic control circuit 40, the inverter 42, the inverter 44, etc.) provided in the vehicle 10.

[0022] The electronic control unit 90 calculates the required driving torque Tr for the vehicle 10 by the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to a predetermined driving demand amount map. Further, the electronic control unit 90 sets the torque distribution ratio γfr (front distribution ratio Fr: rear distribution ratio Rr) of the front and rear wheels, for example, by applying a plurality of driving force related values such as the accelerator opening θacc, the vehicle speed V, the longitudinal acceleration Gx, the yaw rate Ryaw, etc. to a predetermined torque distribution ratio map, and calculates the required front torque Trf (= required driving torque Tr × front distribution ratio Fr) and the required rear torque Trr (= required driving torque Tr × rear distribution ratio Rr). The electronic control unit 90 outputs the engine control signal Se to the engine 12 and the MG1 control signal Sm1 to the inverter 42 so that the driving torques of the engine 12 and the motor MG1 become the required front torque Trf. Further, the MG2 control signal Sm2 is output to the inverter 44 so that the required rear torque Trr is obtained. Thereby, the torque distribution between the front wheels 14 and the rear wheels 34 is performed.

[0023] Figure 2 is a cross-sectional view of the clutch WSC. Figure 2(a) shows the radially outer peripheral portion of the clutch WSC in the upper half of the axis CL accommodated in the rotor support member MGrt. The clutch WSC includes a disk-shaped separator 50 which is an input-side component, a disk-shaped friction material 52 which is an output-side component, a piston 54, a spring 56, and a spring receiving plate 58. The separator 50 is connected to the inner peripheral surface of the bottomed cylindrical rotor support member MGrt so as not to be relatively rotatable and to be movable in the direction of the axis CL. The friction material 52 is connected to the outer peripheral surface of the clutch hub 66 connected to the input shaft 28 so as not to be relatively rotatable and to be movable in the direction of the axis CL.

[0024] The piston 54 is provided with a pressing portion 54a for pressing the separator 50. The spring 56 is interposed between the piston 54 and the spring receiving plate 58 and biases a part of the piston 54 to abut against the base portion 60 on the left side of the paper surface of the rotor support member MGrt. An oil chamber 62 is formed between the piston 54 and the base portion 60 in the rotor support member MGrt. Further, an oil passage 64 communicating with the oil chamber 62 is formed in the base portion 60.

[0025] When the clutch WSC is engaged, the hydraulic oil OIL is supplied from the hydraulic control circuit 40 to the oil chamber 62 via the oil passage 64. When the engagement hydraulic pressure of the clutch WSC (hereinafter referred to as the WSC hydraulic pressure) PR becomes a hydraulic pressure (hereinafter referred to as the piston stroke end arrival pressure) Pe that causes the piston 54 to reach the stroke end position exceeding the biasing force of the spring 56, the piston 54 moves in the direction of the separator 50 where the pistons 54 are alternately stacked, and the pressing portion 54a of the piston 54 presses the separator 50 and the friction material 52, and the power transmission due to the slip state of the clutch WSC is started.

[0026] Incidentally, as shown in FIG. 2(b), when power transmission is performed in a slip state of the clutch WSC with the rotor support member MGrt tilted, the separator 50 connected to the rotor support member MGrt contacts the friction material 52 connected to the input shaft 28 in a tilted state. FIG. 2(c) is an enlarged view of the separator 50 and the friction material 52 in (b). When the clutch WSC is in a slip state, the inclination at which the separator 50 and the friction material 52 contact causes abnormal vibration called judder.

[0027] FIG. 3 is an example of a time chart for explaining the control operation of the WSC hydraulic pressure PR of the electronic control device 90 when power transmission is performed in a slip state of the clutch WSC. The broken line indicates the control operation of the conventional example, and the solid line indicates the control operation of the present embodiment. In FIG. 3, the rotor movement start pressure Ps is a hydraulic pressure command value for starting to move the rotor support member MGrt in the thrust direction (leftward) of the bearing LB side in FIG. 2(a).

[0028] In the conventional example, first, from time t00 to time t10, the pre-pressure of the oil chamber 62 is applied. Specifically, at the quick-fill pressure application from time t00 to time t01, the hydraulic oil OIL is supplied and filled into the oil chamber 62. Thereafter, by time t10, the WSC hydraulic pressure PR is stabilized at the thrust application pressure Pa. Next, the WSC hydraulic pressure PR is increased from time t10 when it is stabilized at the thrust application pressure Pa to time t11 to the piston stroke end arrival pressure Pe. At this time, based on the WSC hydraulic pressure PR, a thrust force is generated on the bearing LB side of the rotor support member MGrt and a thrust force is generated on the bearing HB side of the separator 50 and the friction material 52. However, since the WSC hydraulic pressure PR is low and is increased slowly, while the separator 50 and the friction material 52 are moving, the contribution of the thrust force (thrust force) on the bearing LB side of the rotor support member MGrt based on the WSC hydraulic pressure PR is large, and the rotor support member MGrt is moved to the bearing LB side. However, when the WSC hydraulic pressure PR becomes high toward the piston stroke end arrival pressure Pe, the thrust force on the bearing LB side of the rotor support member MGrt and the thrust force on the bearing HB side of the separator 50 and the friction material 52 are balanced, and the rotor support member MGrt stops moving. In this case, as shown in FIG. 2(b), since the separator 50 and the friction material 52 are in contact with each other in an inclined state, abnormal vibration occurs in the slip state of the clutch WSC.

[0029] In this embodiment, in the engagement control of the clutch WSC, by making the action period of the thrust force on the rotor support member MGrt longer than in the prior art, the thrust force sufficiently presses the rotor support member MGrt against the bearing LB side (left direction), and control for correcting the inclination of the rotor support member MGrt (hereinafter referred to as inclination correction control) is performed. The WSC hydraulic pressure PR is increased to the piston stroke end arrival pressure Pe from time t21 after the state of the thrust application pressure Pa is maintained until time t20 after the pre-pressure from t00 to t10. Here, the WSC hydraulic pressure PR is controlled so that the period from t01 to t21 is equal to or longer than a predetermined thrust application time Ta set in advance experimentally or by design. In this way, while the thrust force on the bearing LB side (left direction) of the rotor support member MGrt acts for a long time, the inclination of the rotor support member MGrt with respect to the axis CL is corrected.

[0030] Preferably, the thrust application pressure Pa is preferably changed according to the oil temperature. For example, when the oil temperature is high, since the viscosity of the oil becomes low, the thrust application pressure Pa can be lowered, and fuel efficiency can be improved by not applying unnecessary oil pressure.

[0031] Preferably, the inclination correction control is not performed except for gear ratios where the output torque fluctuation is high, that is, where the vibration transmission sensitivity in the vehicle becomes a problem. For example, the inclination correction control is not performed except for the 1st gear, 2nd gear, and R gear where the vibration transmission sensitivity between the frequencies f1 - f2 shown in FIG. 4 is equal to or higher than the threshold value Rv. The frequencies f1 - f2 and the threshold value Rv are values preset experimentally or by design. Thereby, in gear ratios with low output torque fluctuation, the inclination correction control is not performed, and since the torque transmission reaction is accelerated, drivability is improved.

[0032] Preferably, since the vibration transmission sensitivity and the force due to the specifications of the clutch WSC vary for each vehicle, by not performing the inclination correction control on vehicles with low output torque fluctuation, the torque transmission reaction is accelerated and drivability is improved. The determination of whether the output torque fluctuation is low is made, for example, based on whether the fluctuation width |ΔNout| of the output rotation speed Nout detected by the output rotation speed sensor 74 is equal to or less than a predetermined threshold value. The fluctuation width |ΔNout| is calculated, for example, by extracting the primary component by performing a sequential fast Fourier transform and band - pass filter processing on the output rotation speed Nout. Further, the determination may be made, for example, based on whether the acceleration fluctuation width by the G - sensor 76 provided in the vehicle is equal to or less than a predetermined threshold value.

[0033] Preferably, since there is a possibility that the reaction of the power transmission to the driver's driving force request may be slower than before, the inclination correction control is started at the time of starting the engine 12, which is the stage before the power transmission of the clutch WSC. Thereby, it is possible to quickly react to the driver's driving force request and drivability is improved.

[0034] Preferably, when performing the tilt correction control in the four-wheel drive vehicle 10, in the front-rear wheel torque distribution ratio γfr, the torque distribution ratio of the rear wheels (rear distribution ratio Rr) is increased. As a result, the torque response delay of the front wheels 14 when the tilt correction control is performed is interpolated by an increase in the required rear torque Trr to the rear wheels 34, thereby improving the torque responsiveness.

[0035] As described above, according to the electronic control device 90 of the present embodiment, when the clutch WSC performs power transmission in a slip state, the period during which the WSC hydraulic pressure PR is less than or equal to the piston stroke end arrival pressure Pe and greater than or equal to the rotor movement start pressure Ps is equal to or greater than the period during which the conventional rotor movement start pressure Ps is greater than or equal to a predetermined thrust application time Ta or more. Control of the WSC hydraulic pressure PR is executed. As a result, the tilt of the rotor support member MGrt connected to the clutch WSC is corrected by the WSC hydraulic pressure PR, and abnormal vibration of the vehicle 10 that occurs when the separator 50 and the friction material 52 are tilted and come into contact is suppressed.

[0036] Note that what has been described above is an embodiment of the present invention, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art without departing from the gist thereof.

Explanation of Reference Numerals

[0037] 10: Vehicle, 12: Engine (internal combustion engine), 14: Front wheels (pair of drive wheels), 90: Electronic control device (control device), K0: Clutch (first clutch), MG1: Electric motor, MGrt: Rotor support member, WSC: Clutch (second clutch), Pe: Piston stroke end arrival pressure, Ps: Rotor movement start pressure, Ta: Predetermined thrust application time (predetermined time)

Claims

【Claim 1】 A control device for a vehicle, comprising: a first clutch that disconnects and connects power transmission between an internal combustion engine and an electric motor; a second clutch that disconnects and connects power transmission between the electric motor and a pair of drive wheels; and a rotor support member of the electric motor that houses the second clutch, when the second clutch performs power transmission in a slip state, the engagement hydraulic pressure of the second clutch is equal to or lower than the hydraulic pressure that causes the piston of the second clutch to reach the stroke end position, and the period during which the hydraulic pressure is equal to or higher than the hydraulic pressure that starts moving the rotor support member in the thrust direction is a predetermined time or more. Perform engagement control of the second clutch so that it becomes longer, A vehicle control device characterized by this.

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