JP2012002329A - Control device of vehicle - Google Patents

Abstract

The present invention provides a vehicle control device capable of improving the drivability while maintaining a good connection to normal flex control while suppressing the increase in engine speed at flex start and improving fuel efficiency.
An SLU command pressure, which is a hydraulic pressure command value applied to a linear solenoid valve SLU, is learned and corrected. When the learned and corrected SLU command pressure is equal to or less than a predetermined lower guard value, the SLU command pressure is reduced to a lower guard value. Is given to the linear solenoid valve SLU, so that the engine speed Ne at the flex start is prevented from being blown up and fuel efficiency is improved, while maintaining a good connection to the normal flex control and drivability can be improved.
[Selection] Figure 7

Description

  The present invention relates to a vehicle control apparatus including a lockup clutch, and more particularly to a vehicle control apparatus that controls an engagement hydraulic pressure of a lockup clutch.

  Conventionally, there is a vehicle provided with a hydraulic lockup clutch that directly connects an engine side and an automatic transmission side to a fluid type power transmission device disposed between an engine and an automatic transmission. In such a vehicle, it is widely known to perform engagement / release control of the lockup clutch using a solenoid that continuously changes the engagement hydraulic pressure of the lockup clutch in accordance with a hydraulic pressure command value.

  For example, as a control device for such a vehicle, in control for sliding and starting a lock-up clutch (hereinafter referred to as flex start), a clutch control signal pressure in a predetermined initial engagement section is controlled by a solenoid at a predetermined initial engagement. The one that maintains the pressure and performs the flex start stably has been proposed (for example, see Patent Document 1).

  In this vehicle control device, when the lock-up clutch is controlled to be slipped when the vehicle starts, a predetermined initial engagement pressure is maintained in advance in a predetermined initial engagement section prior to the start of flex start control. As a result, the control deviation at the start of the flex start control of the lockup clutch is reduced, and the flex start control of the lockup clutch at the start of the vehicle is stably executed.

  On the other hand, there are variations in the characteristics of the solenoid, and if the indicated hydraulic pressure for the solenoid is increased, the engagement pressure of the lockup clutch may increase more than necessary, and an engagement shock may occur. For this reason, in a vehicle control device, it is considered to perform learning control to weaken the command pressure for the solenoid so that the engagement pressure of the lockup clutch does not increase unnecessarily.

JP 2005-016563 A

  However, in such a conventional vehicle control device, if the engagement pressure of the lock-up clutch is weakened too much, the engagement pressure is reduced when the lock-up clutch flex control during normal driving is connected from the flex start. There was a problem that the difference was large and a shock might occur.

  The present invention has been made to solve such a conventional problem, and suppresses the increase in the engine speed at the flex start and improves the fuel efficiency, while maintaining a good connection to the normal flex control, It is an object of the present invention to provide a vehicle control device capable of improving safety.

  In order to solve the above-described problems, a vehicle control apparatus according to the present invention includes: (1) a hydraulic power transmission device with a lock-up clutch disposed between an engine and an automatic transmission; and the lock-up clutch. A control device for a vehicle, comprising: a solenoid that continuously changes a combined hydraulic pressure; and a lockup clutch hydraulic pressure control unit that applies a predetermined hydraulic pressure command value to the solenoid and controls an engagement hydraulic pressure of the lockup clutch; , A differential rotation detecting means for detecting a change amount of the differential rotational speed between the input side rotational speed and the output side rotational speed of the fluid power transmission device, and within a predetermined time from establishment of a predetermined flex start control start condition, Oil pressure learning means for learning and correcting the oil pressure command value on the condition that the amount of change in the differential rotation speed detected by the differential rotation detection means is less than or equal to a predetermined value. The up-clutch hydraulic pressure control means supplies the learning-corrected hydraulic pressure command value to the solenoid on condition that the flex start control start condition is satisfied, and the learning-corrected hydraulic pressure command value is less than a predetermined lower limit guard value. In some cases, the hydraulic pressure command value is given to the solenoid as the lower limit guard value.

  With this configuration, the hydraulic pressure command value given to the solenoid is learned and corrected, and when the learned and corrected hydraulic pressure command value is less than or equal to a predetermined lower limit guard value, the hydraulic pressure command value is given to the solenoid as the lower limit guard value. While improving the fuel efficiency by suppressing the engine speed increase at, the connection to the normal flex control can be maintained well and the drivability can be improved.

  The vehicle control apparatus according to the present invention is the vehicle control apparatus according to (1), further comprising (2) an operation state detection unit that detects an operation state of the vehicle, and the lockup clutch hydraulic control unit. Is configured to determine a hydraulic pressure command value of the solenoid based on the operational state detected by the operational state detecting means, and to give the determined hydraulic pressure command value to the solenoid.

  With this configuration, the hydraulic pressure command value of the solenoid is determined based on the operating state, and the determined hydraulic pressure command value is given to the solenoid, so that the engagement hydraulic pressure of the lockup clutch according to the operating state is ensured and the drivability is improved. be able to.

  Further, the vehicle control device according to the present invention is the vehicle control device according to (2), wherein (3) the lockup clutch hydraulic pressure control means has a predetermined operation state detected by the operation state detection means. On the condition that the vehicle is in a low load starting state, a predetermined low load starting hydraulic pressure command value is given to the solenoid regardless of the learning correction.

  With this configuration, in a low load start state in which the control of the lockup clutch greatly affects drivability, a dedicated low load start hydraulic pressure command value is given, so that drivability at low load start can be improved. .

  Furthermore, the vehicle control device according to the present invention is the vehicle control device according to (3), wherein (4) the lockup clutch hydraulic pressure control means sets the low load start hydraulic pressure command value to the lower limit guard value. It has the structure characterized by these.

  With this configuration, the oil pressure command value at the time of low load start is set as the lower limit guard value, so that the connection to the normal flex control can always be kept good and drivability can be improved even at times other than the time of low load start.

  Further, the vehicle control device according to the present invention is the vehicle control device according to any one of (1) to (4), wherein (5) the lockup clutch hydraulic pressure control means is connected to the driving state detection means. According to the detected driving state, a hydraulic command value for releasing the lockup clutch is given to the solenoid when a high load start condition is established.

  With this configuration, at the time of high load start, the lock-up clutch is released, so that the torque converter is in the converter state, a desired torque increasing function works, acceleration performance can be improved, and drivability can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of the vehicle which keeps the connection to normal flex control favorable, and improves drivability can be provided, suppressing the blowing-up of the engine speed in a flex start, and improving a fuel consumption. .

It is a schematic block block diagram of the vehicle provided with the control apparatus which concerns on embodiment of this invention. It is a schematic block block diagram showing the structure of the transmission in embodiment of this invention. It is an operation | movement table | surface which shows the engagement state of the friction engagement apparatus which implement | achieves each gear stage in embodiment of this invention. It is a circuit diagram which shows the principal part schematic structure of the hydraulic control circuit in embodiment of this invention. It is a graph which shows the relationship between the signal pressure Plin for flex control output from the linear solenoid valve SLU in embodiment of this invention, and the pressure difference (DELTA) P of the engagement side of a lockup clutch, and a releasing side. It is a timing chart explaining the timing of the flex start in the embodiment of the present invention. It is a timing chart explaining the timing of the flex start in the embodiment of the present invention. It is a flowchart which shows the vehicle control process in embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
First, the configuration of a vehicle including a control device according to an embodiment of the present invention will be described with reference to the schematic block configuration diagram of the vehicle shown in FIG. 1 and the schematic block configuration diagram of the transmission shown in FIG.

  As shown in FIG. 1, the vehicle 10 according to the present embodiment transmits an engine 20 as a power source and power generated in the engine 20, that is, torque, and a speed ratio according to the traveling state of the vehicle 10. The transmission 30 to be changed, the differential mechanism 40 for distributing the torque transmitted from the transmission 30 to the drive shafts 51L and 51R as drive shafts, and the vehicle 10 is driven by being rotated by the power transmitted from the drive shafts 51L and 51R. Drive wheels 52L and 52R to be driven.

  The vehicle 10 also includes an ECU (Electronic Control Unit) 100 as a vehicle electronic control device for controlling the entire vehicle 10 and a hydraulic control device 120 that controls the transmission 30 with hydraulic pressure. Further, the vehicle 10 includes a crank angle sensor 131, a drive shaft rotational speed sensor 132, an input shaft rotational speed sensor 133, an output gear rotational speed sensor 134, a shift sensor 141, an accelerator opening sensor 142, a foot A brake sensor (hereinafter referred to as “FB sensor”) 143, a throttle opening sensor 145, an intake air amount sensor 151, an intake air temperature sensor 152, a cooling water temperature sensor 153, an oil temperature sensor 154, and other not shown. Various sensors are provided. Each sensor provided in the vehicle 10 outputs a detected detection signal to the ECU 100.

  The engine 20 is configured by a known power unit that outputs torque by burning a mixture of hydrocarbon fuel such as gasoline or light oil and air in a combustion chamber of a cylinder (not shown). The engine 20 intermittently repeats intake, combustion, and exhaust of the air-fuel mixture in the combustion chamber to reciprocate the piston in the cylinder, and rotates the crankshaft 21 (see FIG. 2) connected to the piston so that power can be transmitted. As a result, torque is transmitted to the transmission 30. The fuel used for the engine 20 may be an alcohol fuel containing alcohol such as ethanol.

  The transmission 30 receives the torque output from the engine 20 via the crankshaft 21, changes the gear ratio according to the traveling state of the vehicle 10, and transmits to the differential mechanism 40 by the reduction gear mechanism 90 (see FIG. 2). It is designed to output. Details of the transmission 30 will be described later.

  The differential mechanism 40 allows a difference in rotational speed between the drive wheel 52L and the drive wheel 52R when traveling on a curve or the like. The differential mechanism 40 distributes the torque input by the reduction gear mechanism 90 to the drive shafts 51L and 51R and outputs it. Note that the differential mechanism 40 may be capable of taking a differential lock state in which the drive shafts 51L and 51R have the same rotation and do not allow a difference in rotational speed between the drive wheels 52L and the drive wheels 52R.

  The ECU 100 includes a CPU (Central Processing Unit) 100a as a central processing unit, a ROM (Read Only Memory) 100b for storing fixed data, a RAM (Random Access Memory) 100c for temporarily storing data, and rewritable. An EEPROM (Electrically Erasable and Programmable Read Only Memory) 100d and an input / output interface circuit (I / F and illustration) 100e, each of which is a non-volatile memory, control the vehicle 10.

  As will be described later, the ECU 100 is connected to a crank angle sensor 131, a drive shaft rotational speed sensor 132, an accelerator opening sensor 142, and the like. The ECU 100 detects the engine speed Ne, the vehicle speed V (the traveling speed of the vehicle 10), the accelerator opening Acc, and the like based on the detection signals output from these sensors.

  Further, the ECU 100 controls the hydraulic control device 120 to control the hydraulic pressure of each part of the transmission 30. Thereby, the ECU 100 can change the transmission gear ratio of the transmission 30.

  Further, the ROM 100b of the ECU 100 stores a throttle opening degree control map, a shift diagram, a lockup control map, specification values of the vehicle 10, an operation table for realizing each shift stage, a program for executing vehicle control, and the like. Has been.

  The throttle opening degree control map is a map for obtaining the throttle opening degree θth based on the accelerator opening degree Acc. Further, the throttle opening degree control map may have a plurality of modes, and the modes may be switched according to the traveling state, the traveling path, and the like. The ECU 100 may automatically switch the mode selection in the throttle opening control map according to the traveling state, the traveling path, or the like, or may be switched according to the selection by the driver.

Further, the shift diagram is a map for determining a gear position for automatic shift based on the vehicle speed V and the throttle opening θth. For example, when the vehicle speed V increases at the same throttle opening θth and the vehicle speed V increases and the throttle opening θth is small, exceeding the upshift shift line, the speed is increased to the gear corresponding to that region. shift. On the other hand, when the vehicle speed V decreases at the same throttle opening θth and the vehicle shifts to a region where the vehicle speed V is small and the throttle opening θth is large beyond the downshift line, the gear speed is reduced to the gear corresponding to that region. shift. Similarly, when the throttle opening .theta.th increases at the same vehicle speed V and the vehicle shifts to a region where the vehicle speed V is small and the throttle opening .theta.th is large beyond the downshift shift line, the speed change corresponding to that region is performed. Downshift to stage.
Here, the CPU 100a of the ECU 100 stores, in the RAM 100c, the shift speed determined according to the vehicle speed V and the throttle opening θth based on the shift diagram.

  The lockup control map is a map for determining the lockup state of the torque converter 60 (see FIG. 2) based on the vehicle speed V and the accelerator opening Acc. For example, in a region where the vehicle speed V is large and the accelerator opening degree Acc is small, a lock-up operation region is entered, and the ECU 100 places the torque converter 60 in a lock-up state. Further, in a region where the vehicle speed V is small and the accelerator opening degree Acc is large, the converter region is established, and the ECU 100 is in a converter state in which the lockup of the torque converter 60 is completely released.

  Further, the lockup control map includes a flex lockup operation region between the lockup operation region and the converter region. In this case, when the region corresponding to the vehicle speed V and the accelerator opening degree Acc becomes the flex lockup operation region, the ECU 100 locks the torque converter 60 in the flex lockup state, that is, at a predetermined slip rate. Engage state.

The specification values of the vehicle 10 include vehicle dimensions such as full width and total height, vehicle weight, total engine displacement, minimum turning radius, tire diameter of the vehicle 10 (the diameters of the drive wheels 52L and 52R), and the speed change mechanism 70. Gear ratio etc. are included.
In addition, an operation table for realizing each gear position stored in the ROM 100b of the ECU 100 and a program for executing vehicle control will be described later.

  The hydraulic control device 120 includes linear solenoid valves SLT and SLU as electromagnetic valves controlled by the ECU 100, on / off solenoid valves SL, and linear solenoid valves SL1 to SL5. The hydraulic control device 120 is controlled by the ECU 100 to switch the hydraulic circuit and control the hydraulic pressure by the solenoid valves, and operate each part of the transmission 30. The function of each solenoid valve of the hydraulic control device 120 will be described later.

  The crank angle sensor 131 is controlled by the ECU 100 to detect the number of rotations of the crankshaft 21 and output a detection signal corresponding to the detected number of rotations to the ECU 100. More specifically, the crank angle sensor 131 detects a crank rotation signal by a crank sensor plate (not shown) provided on the crankshaft 21, and detects a crank position and a crank angular velocity. Further, the ECU 100 calculates the rotation speed of the crankshaft 21 from the detection signal output from the crank angle sensor 131 and obtains it as the engine rotation speed Ne.

  The drive shaft rotational speed sensor 132 is controlled by the ECU 100 to detect the rotational speed of the drive shaft 51L (or 51R) and output a detection signal corresponding to the detected rotational speed to the ECU 100. . Further, the ECU 100 is configured to acquire the rotational speed of the drive shaft 51L (or 51R) represented by the detection signal output from the drive shaft rotational speed sensor 132 as the drive shaft rotational speed Nd. Further, the ECU 100 calculates the vehicle speed V based on the drive shaft speed Nd acquired from the drive shaft speed sensor 132.

The input shaft rotational speed sensor 133 is controlled by the ECU 100 to detect the rotational speed of the input shaft 71 (see FIG. 2) and output a detection signal corresponding to the detected rotational speed to the ECU 100. Yes. Further, the ECU 100 acquires the rotation speed of the input shaft 71 represented by the detection signal output from the input shaft rotation speed sensor 133 as the input shaft rotation speed Nm.
The input shaft 71 is connected to the turbine shaft 62 (see FIG. 2) of the torque converter 60 and has the same rotational speed as that of the turbine shaft 62. Therefore, the input shaft 71 is detected by the input shaft rotational speed sensor 133 below. The input shaft rotation speed Nm is defined as the turbine rotation speed Nt.

  The output gear rotation speed sensor 134 is controlled by the ECU 100 to detect the rotation speed of the output gear 72 (see FIG. 2) and to output a detection signal corresponding to the detected rotation speed to the ECU 100. It has become. Further, the ECU 100 acquires the rotation speed of the output gear 72 represented by the detection signal output from the output gear rotation speed sensor 134 as the output gear rotation speed Nc.

  Further, the ECU 100 detects the input shaft rotational speed Nm acquired from the input shaft rotational speed sensor 133, that is, the input rotational speed of the speed change mechanism 70 (see FIG. 2) and the output gear rotational speed acquired from the output gear rotational speed sensor 134. Based on the number Nc, that is, the output rotational speed of the transmission mechanism 70, the speed ratio γ (= the actual rotational speed Nm of the input shaft 71 / the actual rotational speed Nc of the output gear 72) can be calculated. It is like that.

  The shift sensor 141 is controlled by the ECU 100 to detect which of the plurality of switching positions the shift lever (not shown) is in, and outputs a detection signal representing the shift lever switching position to the ECU 100. It is supposed to be. In addition, the ECU 100 acquires the shift lever switching position indicated by the detection signal output from the shift sensor 141 as the shift position Psh.

  Here, the shift lever includes a D position corresponding to a drive range (hereinafter simply referred to as a D range), an N position corresponding to a neutral range, an R position corresponding to a reverse range, and parking from the rear to the front of the vehicle 10. The P position corresponding to the range is taken.

  When the shift lever is located in the D range, the speed stage of the speed change mechanism 70, which will be described later, is configured to form any one of the first speed to the sixth speed, and as will be described later, the ECU 100 A gear position is selected from the gear positions based on the vehicle speed V and the throttle opening θth.

  Further, the shift lever includes an M position representing a manual position for shifting the shift stage of the transmission mechanism 70 in a manual shift mode (sequential shiftmatic mode: hereinafter simply referred to as S range), and a plus position for instructing an upshift. (+ Position) and a minus position (− position) for instructing a downshift. The M position is located beside the D position, and the shift lever is held at the M position by a spring (not shown) when moved sideways from the D position.

  The accelerator opening sensor 142 is controlled by the ECU 100 to detect an amount of depression (hereinafter referred to as a stroke) by which an accelerator pedal (not shown) is depressed, and outputs a detection signal corresponding to the detected stroke to the ECU 100. It is supposed to be. Further, the ECU 100 calculates the accelerator opening Acc from the accelerator pedal stroke represented by the detection signal output from the accelerator opening sensor 142.

  The FB sensor 143 is controlled by the ECU 100 to detect a depression amount (hereinafter referred to as a stroke) by which a foot brake pedal (not shown) is depressed, and outputs a detection signal corresponding to the detected stroke amount to the ECU 100. It is supposed to be. Further, the ECU 100 calculates the foot brake pedal force Bf from the stroke of the foot brake pedal represented by the detection signal output from the FB sensor 143.

  The FB sensor 143 provides a predetermined threshold value for the foot brake pedal stroke, not the foot brake pedal effort Bf representing the foot brake pedal stroke. A foot brake on / off signal may be output depending on whether or not it has been exceeded. Further, the FB sensor 143 detects a hydraulic pressure applied to a brake main body (not shown) provided on the drive wheels 52L and 52R, and outputs a detection signal representing the hydraulic pressure applied to the brake main body to the ECU 100. Good. Also in this case, the FB sensor 143 provides a predetermined threshold value for the hydraulic pressure of the brake cylinder, and outputs a foot brake on / off signal depending on whether or not the hydraulic pressure of the brake cylinder exceeds this threshold value. Good.

  Here, the foot brake pedal transmits the depressed stroke to a brake master cylinder (not shown). The brake master cylinder generates a hydraulic pressure corresponding to the stroke transmitted from the foot brake pedal. The hydraulic pressure generated in the brake master cylinder is transmitted to the brake main body provided on each drive wheel 52L, 52R via a brake actuator (not shown). The brake body converts the transmitted hydraulic pressure into a mechanical force to brake the drive wheels 52L and 52R.

The throttle opening sensor 145 is controlled by the ECU 100 to detect the opening of a throttle valve that is driven by a throttle actuator (not shown), and outputs a detection signal corresponding to the detected opening to the ECU 100. ing. In addition, the ECU 100 is configured to acquire the throttle valve opening indicated by the detection signal output from the throttle opening sensor 145 as the throttle opening θth.
Further, since the ECU 100 obtains the throttle opening degree θth from the accelerator opening degree Acc based on the throttle opening degree control map, the ECU 100 obtains it from the throttle opening degree control map without using the detection signal output from the throttle opening degree sensor 145. The throttle opening θth can also be used as a detection value.

  The intake air amount sensor 151 is controlled by the ECU 100 to detect the amount of air drawn from an intake valve (not shown) of the engine 20 and output a detection signal corresponding to the detected air amount to the ECU 100. ing. Further, the ECU 100 acquires the intake air amount Qar of the engine 20 from the detection signal output from the intake air amount sensor 151.

  The intake air temperature sensor 152 is controlled by the ECU 100 to detect the temperature of air sucked from the intake valve of the engine 20 and output a detection signal corresponding to the detected temperature to the ECU 100. Yes. Further, the ECU 100 acquires the intake air temperature Tar of the engine 20 from the detection signal output from the intake air temperature sensor 152.

  The cooling water temperature sensor 153 is controlled by the ECU 100 to detect the temperature of cooling water that cools a cylinder (not shown) of the engine 20 (hereinafter simply referred to as cooling water for the engine 20), and detects the detected temperature according to the detected temperature. A signal is output to the ECU 100. Further, the ECU 100 acquires the coolant temperature Tw of the engine 20 from the detection signal output from the coolant temperature sensor 153.

  The oil temperature sensor 154 is controlled by the ECU 100 to detect the temperature of oil in the hydraulic circuit in the transmission 30 and the hydraulic control device 120 (hereinafter, simply referred to as oil temperature or oil temperature), and to detect the detected temperature. A corresponding detection signal is output to the ECU 100. Further, the ECU 100 acquires the oil temperature Tf from the detection signal output from the oil temperature sensor 154.

  Next, a detailed configuration of the transmission 30 in the present embodiment will be described with reference to a schematic block configuration diagram shown in FIG.

As shown in FIG. 2, the transmission 30 includes a torque converter 60 that transmits torque output from the engine 20, a rotation speed of an input shaft 71 that is an input shaft, and a rotation speed of an output gear 72 that is an output gear. A speed change mechanism 70 that performs speed change, and a reduction gear mechanism 90 that inputs torque from the speed change mechanism 70 and increases the driving force while reducing the rotational speed and outputs the same to the differential mechanism 40 are provided.
Further, the transmission 30 is provided with the aforementioned input shaft rotational speed sensor 133 and the output gear rotational speed sensor 134.

  The torque converter 60 is disposed between the engine 20 and the transmission mechanism 70, changes the direction of the oil flow, the pump impeller 63 that inputs torque from the engine 20, the turbine runner 64 that outputs torque to the transmission mechanism 70, and the oil flow direction. A stator 66 and a lock-up clutch 67 that directly connects the pump impeller 63 and the turbine runner 64 are provided to transmit torque via oil.

  The pump impeller 63 is connected to the crankshaft 21 of the engine 20. Further, the pump impeller 63 is rotated integrally with the crankshaft 21 by the torque of the engine 20.

  The turbine runner 64 is connected to the turbine shaft 62, and the turbine shaft 62 is connected to the speed change mechanism 70. The turbine shaft 62 is connected to an input shaft 71 that is an input shaft of the speed change mechanism 70. The turbine runner 64 is rotated by the flow of oil pushed out by the rotation of the pump impeller 63, and outputs the rotation of the crankshaft 21 of the engine 20 to the transmission mechanism 70 via the turbine shaft 62. .

  The stator 66 is rotatably supported by the housing 31 of the transmission 30 serving as a non-rotating member via a one-way clutch 65. The stator 66 flows out of the turbine runner 64 and again changes the direction of the oil flowing into the pump impeller 63 to change the force to further rotate the pump impeller 63. The stator 66 is prevented from rotating by the one-way clutch 65, and changes the direction in which this oil flows.

  Further, the stator 66 is prevented from idling when the pump impeller 63 and the turbine runner 64 rotate at substantially the same speed, and reverse torque is applied to the turbine runner 64.

The lock-up clutch 67 is directly connected between the pump impeller 63 and the turbine runner 64, and mechanically directly transmits the rotation of the crankshaft 21 of the engine 20 to the turbine shaft 62.
Here, the torque converter 60 transmits rotation between the pump impeller 63 and the turbine runner 64 via oil. Therefore, the rotation of the pump impeller 63 cannot be transmitted 100% to the turbine runner 64. Therefore, when the rotational speed of the crankshaft 21 and the turbine shaft 62 approaches, the lockup clutch 67 is operated to mechanically directly connect the pump impeller 63 and the turbine runner 64, so that the speed change mechanism from the engine 20 is achieved. The transmission efficiency of rotation to 70 is increased, and the fuel efficiency is improved.

Further, the lock-up clutch 67 can realize a flex lock-up that slides at a predetermined slip rate. The state of the lockup clutch 67 (the converter state with the lockup clutch 67 released, the lockup state with the lockup clutch 67 engaged, or the flex lockup state with the lockup clutch 67 slid). Is selected by the CPU 100a of the ECU 100 according to the traveling state of the vehicle 10, specifically, the vehicle speed V and the accelerator opening Acc, based on the lock-up control map stored in the ROM 100b of the ECU 100. It has become.
Further, the pump impeller 63 is provided with a mechanical oil pump 68 that generates hydraulic pressure for shifting the speed change mechanism 70 and hydraulic pressure for supplying oil for operation, lubrication and cooling to each part. ing.

  As described above, the torque converter 60 is disposed between the engine 20 and the speed change mechanism 70 and includes the lockup clutch 67. That is, the torque converter 60 constitutes a fluid power transmission device with a lock-up clutch in the present invention.

  The transmission mechanism 70 includes an input shaft 71, an output gear 72, a first planetary gear device 73, a second planetary gear device 74, a C1 clutch 75, a C2 clutch 76, a B1 brake 77, a B2 brake 78, and a B3. A brake 79 and an F one-way clutch 80 are provided.

The input shaft 71 is directly connected to the turbine shaft 62 of the torque converter 60. Therefore, the input shaft 71 directly inputs the output rotation of the torque converter 60.
The output gear 72 is connected to the carrier of the second planetary gear unit 74 and engages with the counter driven gear 91 of the reduction gear mechanism 90 to function as a counter drive gear. Therefore, the output gear 72 transmits the output rotation of the speed change mechanism 70 to the reduction gear mechanism 90.

  The first planetary gear unit 73 is configured by a single pinion type planetary gear mechanism. The first planetary gear device 73 includes a sun gear S1, a ring gear R1, a pinion gear P1, and a carrier CA1.

  The sun gear S <b> 1 is connected to the input shaft 71. Therefore, the sun gear S <b> 1 is connected to the turbine shaft 62 of the torque converter 60 via the input shaft 71. The ring gear R1 is selectively fixed to the housing 31 of the transmission 30 via the B3 brake 79.

  The pinion gear P1 is rotatably supported by the carrier CA1. The pinion gear P1 is engaged with the sun gear S1 and the ring gear R1. The carrier CA1 is connected to the sun gear S2 of the second planetary gear device 74. Further, the carrier CA1 is selectively fixed to the housing 31 via the B1 brake 77.

  The second planetary gear unit 74 is configured by a Ravigneaux type planetary gear mechanism. The second planetary gear device 74 has a sun gear S2, a ring gear R2 (R3), a short pinion gear P2, a long pinion gear P3, a sun gear S3, a carrier CA2, and a carrier CA3.

  The sun gear S2 is coupled to the carrier CA1 of the first planetary gear device 73. The ring gear R2 (R3) is selectively connected to the input shaft 71 via the C2 clutch 76. The ring gear R2 (R3) is selectively fixed to the housing 31 via a B2 brake 78. Also, the ring gear R2 (R3) is prevented from rotating in the direction opposite to the rotation direction of the input shaft 71 (hereinafter referred to as the reverse direction) by the F one-way clutch 80 provided in parallel with the B2 brake 78. ing.

  The short pinion gear P2 is rotatably supported by the carrier CA2. Short pinion gear P2 is engaged with sun gear S2 and long pinion gear P3. The long pinion gear P3 is rotatably supported by the carrier CA3. Long pinion gear P3 is engaged with short pinion gear P2, sun gear S3, and ring gear R2 (R3).

  The sun gear S3 is selectively connected to the input shaft 71 via the C1 clutch 75. The carrier CA2 is connected to the output gear 72. The carrier CA3 is connected to the carrier CA2 and the output gear 72.

  Further, the B1 brake 77, the B2 brake 78, and the B3 brake 79 are fixed to the housing 31 of the transmission 30. The C1 clutch 75, the C2 clutch 76, the F one-way clutch 80, the B1 brake 77, the B2 brake 78, and the B3 brake 79 (hereinafter simply referred to as the clutch C and the brake B unless otherwise specified) are multi-plate clutches and brakes. The hydraulic friction engagement device is controlled to be engaged by a hydraulic actuator. Further, the clutch C and the brake B correspond to a hydraulic circuit that is switched according to excitation or de-energization of the linear solenoid valves SL1 to SL5, SLU and SLT, and the on / off solenoid valve SL of the hydraulic control device 120, or an operating state of a manual valve (not shown) Thus, the state can be switched between the engaged state and the released state.

  The reduction gear mechanism 90 includes a counter driven gear 91 that inputs torque from the speed change mechanism 70, and a differential drive pinion 92 that outputs torque to the differential mechanism 40.

  Counter driven gear 91 is engaged with output gear 72 of transmission mechanism 70. The differential drive pinion 92 is engaged with the differential ring gear 42 of the differential mechanism 40. The counter driven gear 91 and the differential drive pinion 92 are fixed to the same shaft so as to integrally rotate.

  With this configuration, when the output gear 72 of the speed change mechanism 70 rotates, the reduction gear mechanism 90 rotates the counter driven gear 91 engaged with the output gear 72. When the counter driven gear 91 is rotated, the differential drive pinion 92 is rotated through the same shaft. When the differential drive pinion 92 is rotated, the differential ring gear 42 of the differential mechanism 40 engaged with the differential drive pinion 92 is rotated, and the rotation is transmitted to the differential mechanism 40.

  Therefore, the reduction gear mechanism 90 rotates the torque input from the speed change mechanism 70 in accordance with the gear ratio between the output gear 72 and the counter driven gear 91 and the gear ratio between the differential drive pinion 92 and the differential ring gear 42. While reducing the number, the driving force is increased and transmitted to the differential mechanism 40.

  On the other hand, the differential mechanism 40 includes a hollow differential case 41, a differential ring gear 42 provided on the outer periphery of the differential case 41, a pinion shaft 43 provided inside the differential case 41, differential pinion gears 44a and 44b, and side gears 45L and 45R. And. The differential pinion gears 44a and 44b and the side gears 45L and 45R are bevel gears.

  The differential case 41 is held rotatably about the drive shafts 51L and 51R. The differential ring gear 42 is provided on the outer periphery of the differential case 41 and is engaged with the final drive gear 94 of the reduction gear mechanism 90. The pinion shaft 43 is fixed so as to rotate integrally with the differential case 41 in parallel with the differential ring gear 42.

  The differential pinion gears 44 a and 44 b are provided to be rotatable around the pinion shaft 43. The side gear 45L is provided so as to rotate integrally with the drive shaft 51L, and is engaged with the differential pinion gear 44a and the differential pinion gear 44b. Similarly, the side gear 45R is provided so as to rotate integrally with the drive shaft 51R and is engaged with the differential pinion gear 44a and the differential pinion gear 44b.

  For this reason, in the differential mechanism 40, when the differential pinion gears 44a and 44b do not rotate, the side gear 45L and the side gear 45R rotate equally. On the other hand, in the differential mechanism 40, when the differential pinion gears 44a and 44b are rotated, the side gear 45L and the side gear 45R are relatively reversely rotated. Therefore, the differential mechanism 40 allows a difference in rotational speed between the side gear 45L that rotates integrally with the drive shaft 51L and the side gear 45R that rotates together with the drive shaft 51R, and travels on a curve or the like. The difference in rotational speed between the drive wheel 52L and the drive wheel 52R can be absorbed.

  Next, in the transmission mechanism 70 of the transmission 30 according to the present embodiment, the engagement state of the friction engagement elements that realize the respective shift stages will be described with reference to the operation table shown in FIG.

  As shown in FIG. 3, the operation table for realizing each gear stage indicates the state of engagement and release of each friction engagement device (clutch C, brake B) of the transmission mechanism 70 in order to realize each gear stage. It is shown. In FIG. 3, “◯” represents engagement. “X” represents release. “◎” represents engagement only during engine braking. “Δ” represents engagement only during driving.

  By operating each friction engagement device by the excitation, de-excitation, or current control of the linear solenoid valves SL1 to SL5 provided in the hydraulic control device 120 and the transmission solenoid (not shown) with the combinations shown in this operation table, 1 A forward shift speed of 1st to 6th speed (6th) and a reverse shift speed (R) are formed.

  Based on such an operation table, when realizing the first speed (1st), the ECU 100 engages the F one-way clutch 80 in addition to the engagement of the C1 clutch 75 during driving. On the other hand, when realizing the first speed (1st), the ECU 100 engages the B2 brake 78 in addition to the engagement of the C1 clutch 75 when applying the engine brake.

Further, the ECU 100 engages the C1 clutch 75 and the B1 brake 77 when realizing the second speed (2nd). Further, when realizing the third speed (3rd), the ECU 100 engages the C1 clutch 75 and the B3 brake 79.
In addition, when realizing the fourth speed (4th), the ECU 100 engages the C1 clutch 75 and the C2 clutch 76. Further, when realizing the fifth speed (5th), the ECU 100 engages the C2 clutch 76 and the B3 brake 79. Further, the ECU 100 engages the C2 clutch 76 and the B1 brake 77 when realizing the sixth speed (6th).

Further, the ECU 100 engages the B2 brake 78 and the B3 brake 79 when the reverse gear stage (R) is realized.
Further, the ECU 100 releases all of the C1 clutch 75, the C2 clutch 76, the B1 brake 77, the B2 brake 78, the B3 brake 79, and the F one-way clutch 80 when realizing the neutral range and the parking range. As described above, the transmission mechanism 70 is in a neutral state in which no power is transmitted between the input and output of the transmission mechanism 70 by releasing all the friction engagement devices.

  Therefore, for example, when upshifting from the 3rd speed (3rd) to the 4th speed (4th) based on such an operation table, the ECU 100 releases the B3 brake 79 and engages the C2 clutch 76. It is designed to carry out the grabbing. In addition, when downshifting from the third speed (3rd) to the second speed (2nd), the ECU 100 releases the B3 brake 79 and executes a grip change to engage the B1 brake 77. .

  Further, for example, when the vehicle 10 stops at the second speed (2nd) and then starts, the ECU 100 releases the B1 brake 77 and engages the F one-way clutch 80, thereby driving the first speed during driving. The vehicle 10 is started by realizing (1st).

Next, the function of each solenoid valve of the hydraulic control device 120 will be described.
The linear solenoid valve SLT performs hydraulic control of a line pressure PL (hereinafter referred to as a first line pressure Pl1) which is an original pressure of oil supplied to each part. Specifically, the linear solenoid valve SLT includes a throttle opening θth, an intake air amount Qar of the engine 20, a cooling water temperature Tw of the engine 20, an engine speed Ne, an input shaft speed Nm (turbine speed Nt), and a transmission 30. The ECU 100 controls the first line pressure Pl1 based on the oil temperature Tf, the shift position Psh, the shift range, and the like of the hydraulic control device 120.

The linear solenoid valve SLU performs lock-up control in the torque converter 60. Specifically, the linear solenoid valve SLU includes an engine speed Ne that is an input speed of the torque converter 60, a turbine speed Nt that is an output speed of the torque converter 60, a throttle opening θth, a vehicle speed V, an input torque, and the like. The lockup relay valve 320 (see FIG. 4) and the lockup control valve 360 (see FIG. 4) are regulated to control the lockup clutch 67.
The on / off solenoid valve SL switches the hydraulic pressure of the lockup relay valve 320.

  The linear solenoid valves SL1 to SL5 perform shift control. Linear solenoid valves SL1 and SL2 control the hydraulic pressures of the C1 clutch 75 and the C2 clutch 76. The linear solenoid valves SL3, SL4, and SL5 control the hydraulic pressures of the B1 brake 77, the B2 brake 78, and the B3 brake 79.

The hydraulic control device 120 includes a first regulator valve, a second regulator valve, and a third regulator valve.
The first regulator valve regulates the oil pumped from the oil pump 68 to generate the first line pressure Pl1.

The second regulator valve is a relief-type pressure regulating valve, and corresponds to the torque of the engine 20 by regulating the oil flowing out from the first regulator valve based on the accelerator opening Acc or the throttle opening θth. The second line pressure Pl2 is generated.
The third regulator valve is a pressure reducing valve that uses the first line pressure Pl1 as a source pressure, and generates a constant third line pressure Pl3.

  The oil regulated to the first line pressure Pl1 by the first regulator valve is supplied to the manual valve that is linked to the shift lever. When the shift lever is positioned at a position corresponding to the forward range, oil having a forward position pressure PD equal to the first line pressure Pl1 is supplied from the manual valve to the linear solenoid valves SL1 to SL5. .

  The linear solenoid valves SL1 to SL5 are arranged to correspond to the C1 clutch 75, the C2 clutch 76, the B1 brake 77, the B2 brake 78, and the B3 brake 79, respectively. The ECU 100 controls the hydraulic solenoids PC1, PC2, PB1, PB2, and PB3 by controlling these linear solenoid valves SL1 to SL5 with a solenoid current, and C1 clutch 75, C2 clutch 76, B1 brake 77, B2 brake 78, The engagement and release of the B3 brake 79 are switched and the engagement pressure is adjusted.

  As described above, the speed change mechanism 70 is configured so that the friction engagement device (the first line pressure Pl1 is a source pressure) according to the operating state of the linear solenoid valve SLT and the linear solenoid valves SL1 to SL5 of the hydraulic control device 120. The clutch C and the brake B) are selectively engaged or released and controlled with a predetermined engagement pressure. The speed change mechanism 70 forms a gear position according to the combination of engagement and release of these friction engagement devices (clutch C and brake B), and changes the ratio of the rotational speeds of the input shaft 71 and the output gear 72. It is supposed to be.

  Therefore, the speed change mechanism 70 in the present embodiment is any one of the six forward shift speeds configured from the first speed (1st) to the sixth speed (6th) and the one reverse shift speed as described above. The gear is in a neutral state.

  Next, FIG. 4 shows a schematic configuration of a main part of the hydraulic control circuit according to the embodiment of the present invention, that is, a circuit diagram showing a part related to engagement control of the lock-up clutch 67 in the hydraulic control device 120 and will be described.

  As shown in FIG. 4, the hydraulic control device 120 includes an on / off solenoid valve SL, a lockup relay valve 320, a linear solenoid valve SLU, and a lockup control valve 360.

The on / off solenoid valve SL is switched on / off by a switching electromagnetic solenoid 311 to generate a switching signal pressure Psw.
The lockup relay valve 320 is switched between a release side position where the lockup clutch 67 is released and an engagement side position where the lockup clutch 67 is engaged according to the switching signal pressure Psw generated in the on / off solenoid valve SL. It has become.

The linear solenoid valve SLU is a pressure reducing valve that uses a constant third line pressure Pl3 generated by the third regulator valve as a source pressure, and is controlled by the ECU 100. Further, the linear solenoid valve SLU generates a flex control signal pressure Plin that increases with the drive current Islu input from the ECU 100, and causes the flex control signal pressure Plin to act on the lockup control valve 360. ing.
That is, the linear solenoid valve SLU generates the flex control signal pressure Plin corresponding to the drive current Islu supplied from the ECU 100.

  The lock-up control valve 360 adjusts the pressure difference ΔP between the engagement-side oil chamber 60c and the release-side oil chamber 60o of the lock-up clutch 60 according to the flex control signal pressure Plin output from the linear solenoid valve SLU, and locks the lock-up control valve 360. The slip amount of the up clutch 60 is controlled.

Further, the on / off solenoid valve SL includes a switching electromagnetic solenoid 311, a spherical valve element 312, an input port 313, and an output port 314.
The on / off solenoid valve SL is configured to block the communication between the input port 313 and the output port 314 by the spherical valve element 312 under the control of the ECU 100 when the switching electromagnetic solenoid 311 is in a non-excited state (off state). . The on / off solenoid valve SL is controlled by the ECU 100 so that when the switching electromagnetic solenoid 311 is in an excited state (on state), the input port 313 and the output port 314 are communicated with each other to switch the switching signal pressure Psw to the lock-up relay. It acts on the valve 320.

  The lockup relay valve 320 includes a release port 321, an engagement port 322, an input port 323, a first discharge port 324, a second discharge port 325, a supply port 326, and a spool valve element 327. And a spring 328, a plunger 329, a first oil chamber 331, a second oil chamber 332, and a third oil chamber 333.

  The release side port 321 communicates with the release side oil chamber 60 o of the lockup clutch 67. The engagement side port 322 communicates with the engagement side oil chamber 60 c of the lockup clutch 67. The input port 323 is supplied with the second line pressure Pl2.

  The first discharge port 324 is configured to discharge the oil in the engagement side oil chamber 60 c when the lockup clutch 67 is released. The second discharge port 325 is configured to discharge oil in the release side oil chamber 60 o when the lockup clutch 67 is engaged. A part of the oil discharged from the second regulator valve is supplied to the supply port 326 for cooling when the lock-up clutch 67 is engaged.

  The spool valve element 327 switches the connection state of a plurality of ports. The spring 328 biases the spool valve element 327 toward the off-side position. The plunger 329 is arranged so as to be able to contact the end of the spool valve element 327 on the spring 328 side.

  The first oil chamber 331 is provided between the spool valve element 327 and the plunger 329, and receives the R range pressure Pr that acts on the end surfaces of the spool valve element 327 and the plunger 329. The second oil chamber 332 receives the first line pressure Pl1 that acts on the end surface of the plunger 329 opposite to the first oil chamber 331. The third oil chamber 333 causes the switching signal pressure Psw input from the on / off solenoid valve SL to act on the end surface of the spool valve element 327 opposite to the first oil chamber 331 to generate a thrust toward the on-side position. Therefore, the switching signal pressure Psw is received.

  As described above, when the on / off solenoid valve SL is in the OFF state, the switching signal pressure Psw is not applied to the third oil chamber 333 of the lock-up relay valve 320, and the spool valve element 327 has the spring 328. In accordance with the urging force and the first line pressure Pl1 acting on the second oil chamber 332, it is positioned at the off-side position. Therefore, the input port 323 and the release side port 321 of the lockup relay valve 320 are communicated with each other, so that the hydraulic pressure Poff in the release side oil chamber 60o of the lockup clutch 67 is changed to the hydraulic pressure Pon in the engagement side oil chamber 60c. When the lockup clutch 67 is released, the oil in the engagement side oil chamber 60c is discharged from the first discharge port 324 to the drain via an oil cooler and a check valve (not shown). . In addition, a relief valve (not shown) is provided between the first discharge port 324 and the oil cooler to prevent an excessive pressure rise.

  On the other hand, when the on / off solenoid valve SL is in the on state, the switching signal pressure Psw is applied to the third oil chamber 333 of the lockup relay valve 320, and the spool valve element 327 is connected to the spring 328. The urging force and the first line pressure Pl1 acting on the second oil chamber 332 are opposed to the on-side position. Therefore, the input port 323 and the engagement side port 322, the release side port 321 and the second discharge port 325, and the supply port 326 and the first discharge port 324 of the lockup relay valve 320 are communicated with each other. The hydraulic pressure Pon in the engagement-side oil chamber 60c of the 67 is made higher than the hydraulic pressure Poff in the release-side oil chamber 60o, and the lock-up clutch 67 is engaged. 2 is discharged to the drain via the discharge port 325 and the lockup control valve 360.

  The linear solenoid valve SLU includes a supply port 341, an output port 342, a spool valve element 343, a first spring 344, a second spring 345, a flex control electromagnetic solenoid 346, and an oil chamber 347. Have.

The supply port 341 is supplied with the third line pressure Pl3. The output port 342 outputs the flex control signal pressure Plin.
The spool valve element 343 opens and closes a plurality of ports. The first spring 344 biases the spool valve element 343 in the valve closing direction. The second spring 345 urges the spool valve element 343 in the valve opening direction with a smaller thrust than the first spring 344.

  The flex control electromagnetic solenoid 346 biases the spool valve element 343 in the valve opening direction in accordance with the drive current Islu. The oil chamber 347 is adapted to receive a feedback pressure (flex control signal pressure Plin) for causing the spool valve element 343 to generate thrust in the valve closing direction.

  Therefore, the spool valve element 343 has a biasing force in the valve opening direction by the flex control electromagnetic solenoid 346 and the second spring 345 and a biasing force in the valve closing direction by the feedback pressure applied to the first spring 344 and the oil chamber 347. Actuated to equilibrate.

  The lockup control valve 360 includes a line pressure port 361, a receiving port 362, a drain port 363, a spool valve element 364, a plunger 365, a spring 366, a signal pressure oil chamber 367, and a first oil chamber. 368 and a second oil chamber 369.

  The line pressure port 361 is supplied with the second line pressure Pl2. The receiving port 362 receives oil in the release side oil chamber 60o of the lockup clutch 67 discharged from the second discharge port 325 of the lockup relay valve. The drain port 363 discharges the oil received in the receiving port 362.

  The spool valve element 364 communicates between the receiving port 362 and the drain port 363 (first position in FIG. 4), and the second position (communication between the receiving port 362 and the line pressure port 361). It is provided so as to be movable between the left side position in FIG. The plunger 365 is disposed so as to be able to contact the spool valve element 364 to urge the spool valve element 364 toward the first position. The spring 366 is accommodated in the signal pressure oil chamber 367 and biases the spool valve element 364 in the direction toward the second position.

  The signal pressure oil chamber 367 is used for flex control in order to cause the plunger 365 and the spool valve element 364 to act on the flex control signal pressure Plin to generate thrusts in directions away from each other. The signal pressure Plin is received.

  The first oil chamber 368 causes the plunger 365 to act on the hydraulic pressure Poff in the release-side oil chamber 60o of the lockup clutch 67 to generate a thrust in the direction toward the first position on the plunger 365 and the spool valve element 364. Therefore, the hydraulic pressure Poff is received. The second oil chamber 369 applies a hydraulic pressure Pon in the engagement side oil chamber 60c of the lock-up clutch 67 to the spool valve element 364 to generate a thrust force in the direction toward the second position on the spool valve element 364. The hydraulic Pon is accepted.

  Therefore, when the spool valve element 364 of the lock-up control valve 360 is in the first position, the receiving port 362 and the drain port 363 are communicated, and the oil in the release-side oil chamber 60o of the lock-up clutch 67 is reduced. Discharged. As a result, the pressure difference ΔP (= Pon−Poff) between the oil pressure Pon in the engagement side oil chamber 60c of the lockup clutch 67 and the oil pressure Poff in the release side oil chamber 60o is increased.

  On the other hand, when the spool valve element 364 of the lockup control valve 360 is in the second position, the receiving port 362 and the line pressure port 361 are communicated to each other in the release side oil chamber 60o of the lockup clutch 67. A two-line pressure Pl2 is supplied. As a result, the pressure difference ΔP is reduced.

  Here, the plunger 365 of the lockup control valve 360 has a first land 371 having a sectional area A1 on the first oil chamber 368 side, and a sectional area A2 smaller than the sectional area A1 on the signal pressure oil chamber 367 side. A second land 372 is formed. In addition, the spool valve element 364 of the lock-up control valve 360 includes a third land 373 having a cross-sectional area A3 larger than the cross-sectional area A1 and a cross-sectional area of the first land 371 smaller than the cross-sectional area A3 from the signal pressure oil chamber 367 side. A fourth land 374 having the same cross-sectional area A4 as A1 and a fifth land 375 having the same cross-sectional area A5 as the cross-sectional area A1 are formed. The cross-sectional areas of the first land 371 to the fifth land 375 have a relationship of A2 <A1 (= A4 = A5) <A3.

  Therefore, in a state where the lockup relay valve 320 is in the ON state and the flex control signal pressure Plin is relatively small and the relationship shown in the following equation (1) is satisfied, the plunger 365 of the lockup control valve 360 is Then, they abut against the spool valve element 364 and operate integrally with each other. Thus, the pressure difference ΔP between the oil in the engagement side oil chamber 60c and the release side oil chamber 60o of the lockup clutch 67 is set to a magnitude corresponding to the flex control signal pressure Plin.

A1 * Poff ≧ A2 * Plin Equation (1)
This pressure difference ΔP changes relatively gradually according to the rate of change {(A3−A2) / A1} according to the following equation (2) with respect to the flex control signal pressure Plin. In Expression (2), Fs is the biasing force of the spring 366.

ΔP = Pon-Poff
= {(A3-A2) / A1} Plin + Fs / A1 Formula (2)
However, when the flex control signal pressure Plin becomes larger than a predetermined value PA, the relationship shown in the following equation (3) is established.

A1 * Poff <A2 * Plin Formula (3)
This predetermined PA is a value determined in advance so as to obtain a change range ΔPslip of the pressure difference ΔP that is sufficiently large for the flex control of the lockup clutch 67, and the flex control signal pressure Plin is The above-described cross-sectional areas and the like are set so that the relationship shown in Expression (3) is established when the value PA is reached. Therefore, in a state where the flex control signal pressure Plin is larger than the predetermined value PA and the relationship shown in the equation (3) is established, the plunger 365 and the spool valve element 364 are separated from each other, and the spool valve element 364 It is operated so that the following formula (4) is established.

A3 * Plin> A5 * Pon + Fs (4)
However, in a state in which the spool valve element 364 is operated so that the expression (4) is established, the lock-up control valve 360 is in communication with the receiving port 362 and the drain port 363. Since the hydraulic pressure Poff in the release side hydraulic chamber 60o of 67 is further reduced to atmospheric pressure, the pressure difference ΔP = ΔPmax = Pon is established and the complete engagement is established.

A solid line shown in FIG. 5 indicates a change characteristic of the pressure difference ΔP obtained by the operation of the lockup control valve 360 with respect to the flex control signal pressure Plin.
Also, as shown in FIG. 5, when the flex control signal pressure Plin decreases and becomes equal to or less than a value PB that satisfies the following equation (5), the pressure difference ΔP = ΔPmin = 0, and therefore, the lockup relay valve Despite 320 being in the on state, the lockup clutch 67 is released.

A3 * Plin <A5 * Pon (5)
As described above, the engagement hydraulic pressure of the lockup clutch 67 is continuously changed by the flex control signal pressure Plin. Therefore, the linear solenoid valve SLU continuously changes the engagement hydraulic pressure of the lockup clutch 67. That is, the linear solenoid valve SLU constitutes a solenoid in the present invention.

  Hereinafter, the characteristic structure of the vehicle 10 provided with the control apparatus in embodiment of this invention is demonstrated.

  The ECU 100 determines the differential rotation speed ΔN (= Ne−Nt) between the engine rotation speed Ne detected by the crank angle sensor 131 and the turbine rotation speed Nt detected by the input shaft rotation speed sensor 133, that is, the input side rotation of the torque converter 60. The amount of change in the difference rotational speed ΔN between the number and the output side rotational speed is detected. That is, the ECU 100 constitutes a differential rotation detection means in the present invention.

  Further, the ECU 100 provides a hydraulic pressure command value to be given to the linear solenoid valve SLU on the condition that the amount of change in the differential rotational speed ΔN is equal to or less than a predetermined value within a predetermined time after the predetermined flex start control start condition is satisfied. Learning correction. That is, the ECU 100 constitutes a hydraulic pressure learning means in the present invention. The above conditions such as the flex start control start condition will be described later.

  Further, the ECU 100 detects the driving state of the vehicle 10 based on detection signals detected by the various sensors 131 to 154. That is, the ECU 100 constitutes an operating state detection unit in the present invention.

  The ECU 100 controls the engagement hydraulic pressure of the lockup clutch 67 by giving a predetermined hydraulic pressure command value to the linear solenoid valve SLU. Further, the ECU 100 gives the hydraulic pressure command value corrected by learning to the linear solenoid valve SLU on condition that the flex start control start condition is satisfied, and the hydraulic pressure command value corrected by learning is equal to or smaller than a predetermined lower limit guard value. The hydraulic pressure command value is given to the linear solenoid valve SLU as a lower limit guard value.

  Further, the ECU 100 determines a hydraulic pressure command value for the linear solenoid valve SLU based on the detected operating state, and gives the determined hydraulic pressure command value to the linear solenoid valve SLU. In addition, the ECU 100 is configured to give a predetermined low load start hydraulic pressure command value to the linear solenoid valve SLU regardless of the learning correction on condition that the detected driving state is a predetermined low load start state. . Further, the ECU 100 sets the low load start hydraulic pressure command value as a lower limit guard value.

  Further, the ECU 100 is configured to give a hydraulic pressure command value for releasing the lockup clutch 67 to the linear solenoid valve SLU in accordance with the establishment of the high load start condition according to the detected operation state. That is, the ECU 100 constitutes a lockup clutch hydraulic pressure control means in the present invention.

  FIG. 6 and FIG. 7 show timing charts of the flex start in the embodiment of the present invention, and the change of the hydraulic pressure instruction value and the input / output rotational speed for the lockup clutch 67 at the flex start will be described. Here, the timing charts shown in FIGS. 6 and 7 indicate the engine speed Ne, the turbine speed Nt, the SLU command pressure, the SL command, and the throttle opening in order from the top. The SLU indicated pressure indicates a hydraulic pressure command value that the ECU 100 gives to the linear solenoid valve SLU.

  First, the ECU 100 increases the throttle opening θth and outputs an SL instruction (turns on) when the flex start condition is satisfied, for example, when the accelerator pedal 212 is depressed. In addition, the ECU 100 increases the SLU instruction pressure to Pfmax greatly for a certain period of time (between t0 and t1) and decreases it to the lockup engagement start pressure. This temporary increase in the SLU command pressure is performed in order to reduce a margin for releasing the lock-up clutch 67, so-called play. Therefore, the fixed time (between t0 and t1) and the SLU command pressure (Pfmax) to be increased are values determined by this play amount.

  The throttle opening θth is increased based on the depression amount of the accelerator pedal 212. When the depression of the accelerator pedal 212 is maintained, the throttle opening θth is maintained at a value based on the accelerator opening Acc at which the depression is maintained (after t2). ).

  The ECU 100 maintains this value for a predetermined time (between t1 and t3) after reducing the SLU command pressure to the lockup engagement start pressure. Thereafter, the ECU 100 gradually increases the SLU command pressure to the lockup engagement pressure (between t3 and t4), and when it increases to the lockup engagement pressure, maintains the lockup engagement pressure (from t4). (Up to t5), take over acceleration flex control. This series of changes in the SLU command pressure is indicated by broken lines in FIGS.

  From this flex start until the acceleration flex is taken over, the turbine rotational speed Nt gradually increases from 0 rotation, and the engine rotational speed Ne increases from the idle rotational speed to a large extent, and then the increase amount is small. , Come down a little. Therefore, the amount of change in the difference rotational speed ΔN (= Ne−Nt) between the engine rotational speed Ne and the turbine rotational speed Nt is a positive value at the beginning of the flex start, but becomes 0 at a predetermined time. Negative value.

  By the way, since the linear solenoid valve SLU has hardware variations, even if the same SLU command pressure is given from the ECU 100, the output pressure varies from individual to individual, so that the lockup clutch 67 is set to a pressure higher than the target pressure. In some cases, the engine speed Ne decreases early. That is, the torque on the engine 20 side is transmitted too quickly to the drive wheels 52L and 52R side via the turbine 67 side, and hence the transmission, and a shock may occur, resulting in a loss of drivability. For this reason, when such a shock occurs, so-called learning control is performed in which the SLU command pressure is weakened in the next flex start control. Here, the determination of the occurrence of the shock is made when the change amount of the differential rotation speed ΔN becomes a negative value within a predetermined time from the start of the flex start control.

  In the learning control at the flex start, the ECU 100 increases the SLU command pressure to a predetermined time (between t0 and t1) Pfmax, and then decreases the command by a predetermined learning value from the previous lockup engagement start pressure. Pressure (between t1 and t5), and the acceleration flex control is taken over as it is. This series of changes in the SLU indicated pressure is indicated by a one-dot chain line in FIG.

  Further, when it is determined that a shock has occurred even by this learning control, the learning control is performed again so that the SLU command pressure is lowered until it is not determined that a shock has occurred. This series of changes in the SLU indicated pressure is indicated by a two-dot chain line in FIG.

  However, if the SLU command pressure is excessively lowered by learning control, the hydraulic pressure difference becomes large when taking over to the acceleration flex control, so that a so-called hydraulic step is generated, and a shock may occur at the time of taking over.

  Therefore, in the present invention, in learning control in flex start control, a lower limit guard value is provided when the SLU command pressure is lowered, and the SLU command pressure is not lowered below this lower guard value.

  Furthermore, in the vehicle control apparatus of the present embodiment, in the learning control in the flex start control, the time from when the lockup engagement start pressure is lowered to the time when the acceleration flex control is taken over (between t1 and t5), The SLU command pressure is obtained by lowering the SLU command pressure by a certain learning value. This series of changes in the SLU indicated pressure is indicated by a one-dot chain line in FIG. Then, learning control is performed until it is not determined that a shock has occurred, and when the SLU command pressure falls below the lower limit guard value, the SLU command pressure is set to the lower limit guard value. This series of changes in the SLU indicated pressure is indicated by a solid line in FIG.

  In the flex start control, when a predetermined number of shocks have not occurred, the SLU command pressure is sequentially returned by a certain learning value.

  Next, FIG. 8 shows a flowchart showing a vehicle control process in the embodiment of the present invention, and the operation will be described.

  The flowchart shown in FIG. 8 represents the execution contents of a vehicle control process program executed by the CPU 100a of the ECU 100 using the RAM 100c as a work area. The vehicle control processing program is stored in the ROM 100b of the ECU 100.

  As shown in FIG. 8, first, the CPU 100a of the ECU 100 determines whether or not a flex start control start condition is satisfied (step S11). Specifically, the CPU 100a of the ECU 100 determines whether or not the flex start control region determination has been established, for example, whether or not the value indicated by the turbine speed Nt and the accelerator opening Acc is within the flex start control region. Determine.

  Further, the CPU 100a of the ECU 100 determines whether or not the shift position Psh is the “D position”, that is, the “D range”. Further, the CPU 100a of the ECU 100 determines whether the brake is off (whether the foot brake pedal force Bf is equal to or less than a predetermined value or whether a brake off signal is detected), and whether the current gear is the first speed. . Furthermore, the CPU 100a of the ECU 100 determines whether it is not prohibited by fail-safe, whether the accelerator opening Acc is equal to or greater than a predetermined value, or whether the oil temperature condition is satisfied.

  Furthermore, the CPU 100a of the ECU 100 determines whether the shift control, the garage control, and the N control (neutral control) are not in operation or whether there is a stop history of the vehicle 10. Then, the CPU 100a of the ECU 100 determines that the flex start control start condition is satisfied if all of the above conditions are satisfied.

  When the CPU 100a of the ECU 100 determines that the flex start control start condition is not satisfied (determined as NO in step S11), the vehicle control process ends.

  When the CPU 100a of the ECU 100 determines that the flex start control start condition is satisfied (YES in step S11), the CPU 100a performs the following flex start control (step S12 to step S22).

  When starting the flex start control (step S12), the CPU 100a of the ECU 100 first sets the SLU command pressure to Pfmax (step S13).

  Subsequently, the CPU 100a of the ECU 100 outputs the SLU command pressure to the linear solenoid valve SLU (step S14).

  Next, the CPU 100a of the ECU 100 determines whether or not the flex start start operation has ended (step S15). If the flex start start operation has not ended (determined NO in step S15), the process proceeds to step S14. Returning, the SLU command pressure set to Pfmax is continuously output to the linear solenoid valve SLU.

  If the CPU 100a of the ECU 100 determines that the operation at the start of the flex start has been completed (determined as YES in step S15), the CPU 100a acquires the SLU command pressure corresponding to the operating conditions, and stores the acquired SLU command pressure in the RAM 100c. The learned values thus added are added (step S16).

Next, the CPU 100a of the ECU 100 determines whether or not the updated SLU command pressure is equal to or lower than the lower limit guard value stored in the ROM 100d (step S17).
If the SLU command pressure after updating the learning value is equal to or lower than the lower limit guard value (determined as YES in step S17), the CPU 100a of the ECU 100 resets the SLU command pressure to the lower limit guard value (step S18). If the SLU command pressure is not less than or equal to the lower limit guard value (determined as NO in step S17), the set SLU command pressure is output to the linear solenoid valve SLU without changing the SLU command pressure after updating the learning value ( Step S19).

  Next, the CPU 100a of the ECU 100 determines whether or not the “acceleration flex control start condition” is satisfied (step S20), and when the “acceleration flex control start condition” is not satisfied (determined NO in step S20). In step S16, the SLU command pressure corresponding to the operating condition is acquired, the learned value stored in the RAM 100c is added to the acquired SLU command pressure (step S16), and "acceleration flex control start condition" The above process (step S16 to step S20) is repeated until is established.

  When the “acceleration flex control start condition” is satisfied (YES in step S20), the CPU 100a of the ECU 100 performs a learning value update process (step S21).

  Specifically, the CPU 100a of the ECU 100 determines that the amount of change in the differential rotational speed ΔN between the engine rotational speed Ne and the turbine rotational speed Nt is within a preset time after the “flex start control start condition” is satisfied. When the value becomes negative, the learning value is updated to a negative value that lowers the SLU command pressure. Further, the CPU 100a of the ECU 100 did not change the amount of change in the differential rotation speed ΔN but became a positive value within a preset time after the “flex start control start condition” was satisfied. In this case, the learning value is updated to 0.

  Further, the CPU 100a of the ECU 100 continues the predetermined number of times that the change amount of the differential rotation speed ΔN remains a positive value within a preset time after the “flex start control start condition” is satisfied. If this occurs, the learning value is updated to a positive value that increases the SLU command pressure.

  When the learning value update process (step S21) ends, the CPU 100a of the ECU 100 ends the flex start control (step S22), and ends the vehicle control process.

  As described above, the vehicle control apparatus according to the present embodiment learns and corrects the SLU command pressure, which is a hydraulic command value applied to the linear solenoid valve SLU, and the learned and corrected SLU command pressure is equal to or less than a predetermined lower limit guard value. In some cases, the SLU command pressure is applied to the linear solenoid valve SLU as the lower limit guard value, which keeps the connection to the normal flex control good while suppressing the increase in the engine speed Ne at the flex start and improving fuel efficiency. , Drivability can be improved.

  In addition, the vehicle control apparatus according to the present embodiment determines the SLU command pressure of the linear solenoid valve SLU based on the driving state, and gives the determined SLU command pressure to the linear solenoid valve SLU. The engagement hydraulic pressure of the up clutch 67 is ensured, and drivability can be improved.

  Furthermore, the vehicle control apparatus according to the present embodiment provides a dedicated low load start hydraulic pressure command value, that is, a lower limit guard value, in a low load start state where the control of the lockup clutch 67 greatly affects drivability. Therefore, drivability at the time of low load start can be improved.

  Furthermore, since the vehicle control device in the present embodiment uses the low load start hydraulic pressure command value as the lower limit guard value, the vehicle always maintains a good connection to the normal flex control even when the load is low, and the driver Can be improved.

  Further, the vehicle control apparatus in the present embodiment places the lock-up clutch 67 in the released state at the time of high load start, so that the torque converter 60 enters the converter state, the desired torque increasing function works, and the acceleration performance is improved. , Drivability can be improved.

  In addition, in embodiment mentioned above, although demonstrated as what has one ECU, it is not restricted to this, You may be comprised by several ECU. For example, the ECU 100 of the present embodiment may be configured by a plurality of ECUs such as an E-ECU that performs combustion control of the engine 20 and a T-ECU that performs transmission control of the transmission 30. In this case, each ECU inputs and outputs necessary information mutually. In this case, the same effect as that of the vehicle control device described above can be obtained.

  The embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  As described above, the vehicle control device according to the present invention improves the fuel efficiency while suppressing the increase in the engine speed at the flex start, while maintaining a good connection to the normal flex control and improving the drivability. This is useful as a vehicle control device for controlling the engagement hydraulic pressure of the lockup clutch.

DESCRIPTION OF SYMBOLS 10 Vehicle 20 Engine 21 Crankshaft 30 Transmission 40 Differential mechanism 51L, 51R Drive shaft 52L, 52R Drive wheel 60 Torque converter (fluid type power transmission device)
62 Turbine shaft 63 Pump impeller 64 Turbine runner 65 One-way clutch 66 Stator 67 Lock-up clutch 68 Oil pump 70 Transmission mechanism (automatic transmission)
71 Input shaft 72 Output gear 90 Reduction gear mechanism 100 ECU (Lock-up clutch hydraulic control means, differential rotation detection means, hydraulic pressure learning means, operation state detection means)
DESCRIPTION OF SYMBOLS 120 Hydraulic control apparatus 131 Crank angle sensor 132 Drive shaft rotational speed sensor 133 Input shaft rotational speed sensor 134 Output gear rotational speed sensor 141 Shift sensor 142 Accelerator opening sensor 143 Foot brake sensor (FB sensor)
145 Throttle opening sensor 154 Oil temperature sensor 320 Lock-up relay valve 360 Lock-up control valve SLT Linear solenoid valve SLU Linear solenoid valve (solenoid)
SL ON / OFF solenoid valve SL1-SL5 linear solenoid valve

Claims (5)

In a vehicle control device comprising: a fluid power transmission device with a lock-up clutch disposed between an engine and an automatic transmission; and a solenoid that continuously changes an engagement hydraulic pressure of the lock-up clutch.
Lockup clutch hydraulic pressure control means for giving a predetermined hydraulic pressure command value to the solenoid and controlling the engagement hydraulic pressure of the lockup clutch;
Differential rotation detection means for detecting a change amount of the differential rotation speed between the input-side rotation speed and the output-side rotation speed of the fluid power transmission device;
The hydraulic pressure command value is learned and corrected on the condition that the change amount of the differential rotation detected by the differential rotation detection means becomes equal to or less than a predetermined value within a predetermined time from the establishment of the predetermined flex start control start condition. Hydraulic learning means to
The lockup clutch hydraulic pressure control means gives the learned hydraulic pressure command value to the solenoid on condition that the flex start control start condition is satisfied, and the learned hydraulic pressure command value is a predetermined lower limit guard value. In the case of the following, the vehicle control device is characterized in that the hydraulic pressure command value is given to the solenoid as the lower limit guard value. Comprising driving state detecting means for detecting the driving state of the vehicle;
The lockup clutch hydraulic pressure control means determines a hydraulic pressure command value of the solenoid based on an operating state detected by the operating state detection means, and gives the determined hydraulic pressure command value to the solenoid. Item 2. The vehicle control device according to Item 1.   The lock-up clutch hydraulic pressure control means is configured to start the solenoid at a predetermined low load start regardless of the learning correction on the condition that the operation state detected by the operation state detection means is a predetermined low load start state. The vehicle control device according to claim 2, wherein a hydraulic pressure command value is given.   The vehicle control apparatus according to claim 3, wherein the lockup clutch hydraulic pressure control means sets the low load start hydraulic pressure command value as the lower limit guard value.   The lock-up clutch hydraulic pressure control means gives a hydraulic pressure command value for releasing the lock-up clutch to the solenoid when the high load start condition is satisfied according to the driving condition detected by the driving condition detection means. The vehicle control device according to any one of claims 2 to 4, wherein:

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