JP2010007815A - Control device and control method of vehicle - Google Patents

Abstract

A reduction in power transmission capability of a torque converter caused by air mixed in hydraulic oil is suppressed.
When the ECU is in the D position and the vehicle speed is zero (YES in S100), a step of starting a timer (S102) and a predetermined time T (0) elapses. (YES in S104), obtaining the engine speed NE (S106), the engine speed NE is equal to or higher than the reference speed NE (0) (YES in S108), and the brake is turned off. (YES in S110), a program including the step of controlling the lockup clutch (S112) is executed.
[Selection] Figure 7

Description

  The present invention relates to control of a vehicle equipped with an automatic transmission equipped with a lock-up clutch, and more particularly to control of a lock-up clutch when a torque converter of the automatic transmission is in a lost drive state.

  An automatic transmission mounted on a vehicle may have a lockup clutch that enables direct connection between an input side and an output side of a torque converter. By controlling the input side and the output side of the torque converter to be directly connected by engaging this lock-up clutch, the engine brake is effective and the fuel efficiency is improved.

  As such a lockup clutch, for example, Japanese Patent Laying-Open No. 2005-16563 (Patent Document 1) discloses a lockup clutch for a vehicle in which slip control of the lockup clutch that is started when the vehicle starts is stably executed. A control device is disclosed. This control device is a slip control means for adjusting a control hydraulic pressure so that a slip rotation speed of a lockup clutch is a target rotation speed in a vehicle having a fluid transmission device with a lockup clutch between an engine and an automatic transmission. An initial pressure control means for maintaining a control hydraulic pressure at a predetermined initial engagement pressure in a predetermined initial engagement section prior to the start of slip control by the slip control means. , Including.

According to the vehicle lockup clutch control device disclosed in the above publication, the control deviation at the start of the lockup clutch slip control is suitably reduced, so that the lockup clutch slip control at the start of the vehicle is stable. Is executed automatically.
JP 2005-16563 A

  However, in an automatic transmission, the hydraulic oil inside the automatic transmission is difficult to return to the oil pan when the oil temperature is low, so that the oil level is lowered and the hydraulic oil mixed with bubbles is supplied to the components in the automatic transmission. The Rukoto. This is because the viscosity of the hydraulic oil increases at low oil temperatures.

  Therefore, for example, when the vehicle is stopped and the drive position is selected as the shift position of the automatic transmission, only the input shaft of the torque converter rotates and rotation of the output shaft is suppressed. There is a problem that the power transmission capability is reduced due to the retention and accumulation of hydraulic oil bubbles in the torque converter, and the driving force of the vehicle is reduced.

  The vehicle lock-up clutch control device disclosed in the above-mentioned publication does not take into account such a problem, and thus cannot solve the problem.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle control device that suppresses a reduction in power transmission capability of a torque converter caused by air mixed into hydraulic oil. It is to provide a control method.

  In the vehicle control device according to the first aspect of the present invention, the vehicle includes an engine, an automatic transmission connected to the engine, and drive wheels to which the power of the engine is transmitted via the automatic transmission. The automatic transmission includes a torque converter connected to the engine, a lockup clutch provided inside the torque converter, and a transmission mechanism connected to the torque converter. The lockup clutch engages to directly connect the input shaft and the output shaft of the torque converter, and releases the direct connection state by releasing the lockup clutch. The control device includes a detection unit for detecting the engine speed, a first condition that the state of the transmission mechanism is a state in which engine power is transmitted to driving wheels while the vehicle is stopped, and the engine. When the determination condition including the second condition that the rotational speed of the engine is equal to or higher than the reference rotational speed corresponding to the state of the transmission mechanism is satisfied, the power transmission capacity from the engine to the transmission mechanism decreases. Determining means for determining that the vehicle is in a lost drive state, and controlling the lock-up clutch so as to suppress a decrease in power transmission capability according to the state of the vehicle when it is determined that the vehicle is in a lost drive state Control means. A vehicle control method according to a seventh aspect has the same configuration as the vehicle control apparatus according to the first aspect.

  According to the first aspect of the present invention, when the speed change mechanism is in a state of transmitting the engine power to the drive wheels while the vehicle is stopped, It can be determined that the power transmission capability is reduced due to the lost drive state. For this reason, when it is determined that the torque converter is in the lost drive state, the lockup clutch is controlled so as to suppress a decrease in power transmission capability according to the state of the vehicle. Can be moved. Therefore, it is possible to provide a vehicle control device and a control method that suppress a decrease in power transmission capability of the torque converter caused by air mixed into the hydraulic oil.

  In the vehicle control apparatus according to the second aspect of the invention, in addition to the configuration of the first aspect, the determination means may determine whether the second condition is satisfied after a predetermined time has elapsed since the first condition is satisfied. It is determined whether or not is established. A vehicle control method according to an eighth aspect has the same configuration as the vehicle control apparatus according to the second aspect.

  According to the second invention, by determining whether or not the second condition is satisfied after a predetermined time has elapsed since the fluctuation of the engine speed converges after the first condition is satisfied. It is possible to accurately determine whether or not the torque converter is in the lost drive state.

  In the vehicle control apparatus according to the third aspect of the invention, in addition to the configuration of the first or second aspect of the invention, the control means includes means for eliminating the directly connected state of the lockup clutch while the vehicle is stopped, and a torque converter. Means for controlling the lock-up clutch so that the degree of engagement of the lock-up clutch increases when the vehicle starts, when it is determined that the state is a lost drive state. A vehicle control method according to a ninth aspect has the same configuration as the vehicle control apparatus according to the third aspect.

  According to the third invention, when it is determined that the torque converter is in the lost drive state, the lockup clutch is controlled so that the degree of engagement of the lockup clutch increases when the vehicle starts. Thus, the power transmission from the input shaft to the output shaft in the torque converter is assisted by the engagement of the lockup clutch, so that a reduction in the power transmission capability of the torque converter can be suppressed.

  In the vehicle control apparatus according to the fourth aspect of the invention, in addition to the configuration of any one of the first to third aspects, the control means determines whether the engine is in the lost drive state when the torque converter is in the lost drive state. The lockup clutch is controlled so that the rotation speed of the motor becomes the reference rotation speed. A vehicle control method according to a tenth aspect of the invention has the same configuration as the vehicle control apparatus according to the fourth aspect of the invention.

  According to the fourth invention, when it is determined that the torque converter is in the lost drive state, the input shaft in the torque converter is controlled by controlling the lockup clutch so that the engine speed becomes the reference speed. Power transmission from to the output shaft is assisted by engagement of the lockup clutch. Therefore, the automatic transmission can be warmed up by the frictional heat in the lockup clutch while ensuring the driving force at the time of starting. As a result, the lost drive state can be improved.

  A vehicle control apparatus according to a fifth aspect of the invention further includes setting means for setting a reference rotational speed based on the states of the engine and the automatic transmission in addition to the configuration of any one of the first to fourth aspects of the invention. . A vehicle control method according to an eleventh invention has the same configuration as the vehicle control device according to the fifth invention.

  According to the fifth invention, the torque converter is in the lost drive state by setting the reference rotational speed based on the states of the engine and the automatic transmission (for example, fuel injection amount, cooling water temperature, engine oil temperature, AT oil temperature). It can be accurately determined whether or not.

  In the vehicle control device according to the sixth invention, in addition to the configuration of any one of the first to fifth inventions, the determination condition is that the temperature of the hydraulic oil of the automatic transmission is equal to or lower than a predetermined temperature. Further includes conditions. A vehicle control method according to a twelfth aspect of the invention has the same configuration as the vehicle control apparatus according to the sixth aspect of the invention.

  According to the sixth aspect of the present invention, it is accurately determined whether or not the torque converter is in the lost drive state by adding a condition that the temperature of the hydraulic oil of the automatic transmission is equal to or lower than a predetermined temperature as the determination condition. can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
With reference to FIG. 1, the structure of the vehicle 10 carrying the vehicle control apparatus which concerns on embodiment of this invention is demonstrated. The vehicle 10 is a front engine front drive (FF) vehicle. A vehicle other than FF may be used.

  Vehicle 10 includes an engine 1000, an automatic transmission 2000, a differential gear 5000, a drive shaft 6000, a front wheel 7000, and an ECU (Electronic Control Unit) 8000. The vehicle control apparatus according to the present invention is implemented by ECU 8000. Automatic transmission 2000 includes a torque converter 3200, a planetary gear unit 3000, and a hydraulic circuit 4000.

  Engine 1000 is an internal combustion engine that burns a mixture of fuel and air injected from an injector (not shown) in a combustion chamber of a cylinder. The piston in the cylinder is pushed down by the combustion, and the crankshaft is rotated.

  Automatic transmission 2000 is connected to engine 1000 via torque converter 3200. The automatic transmission 2000 changes the rotational speed of the crankshaft to a desired rotational speed by forming a desired shift speed.

  The output gear of automatic transmission 2000 is in mesh with differential gear 5000. A drive shaft 6000 is connected to the differential gear 5000 by spline fitting or the like. Power is transmitted to the left and right front wheels 7000 via the drive shaft 6000.

  The ECU 8000 includes a vehicle speed sensor 8002, a position switch 8006 of a shift lever 8004, an accelerator opening sensor 8010 of an accelerator pedal 8008, a stop lamp switch 8014 of a brake pedal 8012, and a throttle opening sensor 8018 of an electronic throttle valve 8016. The engine speed sensor 8020, the input shaft speed sensor 8022, the output shaft speed sensor 8024, and the oil temperature sensor 8026 are connected via a harness or the like.

  The vehicle speed sensor 8002 detects the speed of the vehicle from the rotational speed of the drive shaft 6000 and transmits a signal representing the detection result to the ECU 8000. The position of shift lever 8004 is detected by position switch 8006, and a signal indicating the detection result is transmitted to ECU 8000. Corresponding to the position of the shift lever 8004, the gear stage of the automatic transmission 2000 is automatically formed. Further, a manual shift mode in which the driver can select an arbitrary gear position may be selected according to the driver's operation.

  Accelerator opening sensor 8010 detects the opening of accelerator pedal 8008 and transmits a signal representing the detection result to ECU 8000. The stop lamp switch 8014 transmits a signal indicating that the brake pedal 8012 is depressed to the ECU 8000 when the depression amount of the brake pedal 8012 is equal to or greater than a predetermined amount. A stroke sensor may be used instead of the stop lamp switch 8014.

  The throttle opening sensor 8018 detects the opening of the electronic throttle valve 8016 whose opening is adjusted by the actuator, and transmits a signal representing the detection result to the ECU 8000. Electronic throttle valve 8016 adjusts the amount of air taken into engine 1000 (output of engine 1000).

  Engine speed sensor 8020 detects the speed of the output shaft (crankshaft) of engine 1000 (hereinafter also referred to as engine speed NE), and transmits a signal representing the detection result to ECU 8000. Input shaft rotational speed sensor 8022 detects input shaft rotational speed (hereinafter also referred to as turbine rotational speed) NT of automatic transmission 2000 and transmits a signal representing the detection result to ECU 8000. Output shaft rotational speed sensor 8024 detects output shaft rotational speed NO of automatic transmission 2000 and transmits a signal representing the detection result to ECU 8000.

  The output shaft of engine 1000 is connected to the input shaft of torque converter 3200, and the output shaft of torque converter 3200 is connected to the input shaft of planetary gear unit 3000, which is a transmission mechanism. The number is the same as the rotational speed of the input shaft of the torque converter 3200. Further, the input shaft rotation speed of automatic transmission 2000 is the same as the rotation speed of the output shaft of torque converter 3200.

  Oil temperature sensor 8026 detects the temperature of hydraulic oil in automatic transmission 2000 and transmits a signal representing the detection result to ECU 8000.

  The ECU 8000 includes a vehicle speed sensor 8002, a position switch 8006, an accelerator opening sensor 8010, a stop lamp switch 8014, a throttle opening sensor 8018, an engine speed sensor 8020, an input shaft speed sensor 8022, an output shaft speed sensor 8024, an oil temperature. Based on a signal sent from the sensor 8026 and the like, a map and a program stored in a ROM (Read Only Memory), the devices are controlled so that the vehicle is in a desired running state.

  In the present embodiment, ECU 8000 has a first gear to a sixth gear when the shift lever 8004 is positioned at the D (drive) position and the D (drive) range is selected as the shift range of automatic transmission 2000. The automatic transmission 2000 is controlled so that any one of the shift stages is formed. By forming one of the first to sixth gears, the automatic transmission 2000 can transmit driving force from the engine 1000 to the front wheels 7000 that are driving wheels.

  When the shift lever 8004 is in the N (neutral) position, when the N (neutral) range is selected as the shift range of the automatic transmission 2000, the automatic transmission 2000 is set in a neutral state (power transmission cut-off state). Is controlled.

  A planetary gear unit 3000 provided in the automatic transmission 2000 will be described with reference to FIG. Planetary gear unit 3000 is connected to a torque converter 3200 having an input shaft 3100 coupled to a crankshaft. Planetary gear unit 3000 includes a first set 3300 of planetary gear mechanisms, a second set 3400 of planetary gear mechanisms, an output gear 3500, a B1 brake 3610, a B2 brake 3620 and a B3 brake 3630 fixed to gear case 3600, and C1. Clutch 3640 and C2 clutch 3650, and one-way clutch F3660 are included.

  The first set 3300 is a single pinion type planetary gear mechanism. First set 3300 includes sun gear S (UD) 3310, pinion gear 3320, ring gear R (UD) 3330, and carrier C (UD) 3340.

  Sun gear S (UD) 3310 is coupled to output shaft 3210 of torque converter 3200. Pinion gear 3320 is rotatably supported by carrier C (UD) 3340. Pinion gear 3320 is in mesh with sun gear S (UD) 3310 and ring gear R (UD) 3330.

  Ring gear R (UD) 3330 is fixed to gear case 3600 by B3 brake 3630. Carrier C (UD) 3340 is fixed to gear case 3600 by B1 brake 3610.

  The second set 3400 is a Ravigneaux type planetary gear mechanism. The second set 3400 includes a sun gear S (D) 3410, a short pinion gear 3420, a carrier C (1) 3422, a long pinion gear 3430, a carrier C (2) 3432, a sun gear S (S) 3440, and a ring gear R. (1) (R (2)) 3450.

  Sun gear S (D) 3410 is coupled to carrier C (UD) 3340. Short pinion gear 3420 is rotatably supported by carrier C (1) 3422. Short pinion gear 3420 is in mesh with sun gear S (D) 3410 and long pinion gear 3430. Carrier C (1) 3422 is coupled to output gear 3500.

  Long pinion gear 3430 is rotatably supported by carrier C (2) 3432. Long pinion gear 3430 is in mesh with short pinion gear 3420, sun gear S (S) 3440, and ring gear R (1) (R (2)) 3450. Carrier C (2) 3432 is coupled to output gear 3500.

  Sun gear S (S) 3440 is coupled to output shaft 3210 of torque converter 3200 by C1 clutch 3640. Ring gear R (1) (R (2)) 3450 is fixed to gear case 3600 by B2 brake 3620 and connected to output shaft 3210 of torque converter 3200 by C2 clutch 3650. The ring gear R (1) (R (2)) 3450 is connected to the one-way clutch F3660 and cannot rotate when the first gear is driven.

  The one-way clutch F3660 is provided in parallel with the B2 brake 3620. That is, the outer race of the one-way clutch F3660 is fixed to the gear case 3600, and the inner race is connected to the ring gear R (1) (R (2)) 3450 via the rotation shaft.

  A lockup clutch 5600 is provided inside the torque converter 3200. The lock-up clutch 5600 is brought into a direct connection state between the input shaft and the output shaft of the torque converter 3200 by being engaged, and is released from the direct connection state. The lock-up clutch 5600 is engaged, released, or semi-engaged by hydraulic pressure supplied from a hydraulic circuit 4000 described later. The hydraulic pressure supplied from the hydraulic circuit 4000 to the lockup clutch 5600 is controlled by the ECU 8000.

  FIG. 3 shows an operation table showing the relationship between the respective shift speeds and the operation states of the clutch elements and the brake elements. By operating each brake element and each clutch element in the combination shown in this operation table, a forward speed of 1st to 6th speed and a reverse speed are formed.

  As shown in FIG. 3, the C1 clutch 3640 is engaged in all of the first to fourth gears. That is, it can be said that the C1 clutch 3640 is an input clutch in the first gear to the fourth gear. C2 clutch 3650 is engaged at the fifth speed and the sixth speed. That is, it can be said that C2 clutch 3650 is an input clutch at the fifth speed and the sixth speed.

  In the present embodiment, the case where the present invention is applied to an automatic transmission having two input clutches will be described, but the number of input clutches is not particularly limited.

  In the present embodiment, when the D position is selected while the vehicle 10 is stopped, the first gear is formed and the C1 clutch 3640 is engaged. Therefore, output torque based on the power of engine 1000 appears on the output shaft of automatic transmission 2000.

  The main part of the hydraulic circuit 4000 will be described with reference to FIGS. The hydraulic circuit 4000 is not limited to the one described below.

  As shown in FIG. 4, a hydraulic circuit 4000 includes an oil pump 4004, a primary regulator valve 4006, a manual valve 4100, a solenoid modulator valve 4200, and an SL1 linear solenoid (hereinafter referred to as SL (1)) 4210. SL2 linear solenoid (hereinafter referred to as SL (2)) 4220, SL3 linear solenoid (hereinafter referred to as SL (3)) 4230, and SL4 linear solenoid (hereinafter referred to as SL (4)) 4240. And an SLT linear solenoid (hereinafter referred to as SLT) 4300 and a B2 control valve 4500.

  The hydraulic source of the automatic transmission 2000 includes an oil pan 4008 for storing automatic transmission fluid (ATF (Automatic Transmission Fluid)), and the hydraulic oil of the oil pan 4008 using the power of the engine 1000 for each friction engagement element. It includes an oil pump 4004 to be supplied and a distribution path 4014 for distributing the hydraulic oil of the oil pan 4008 to the oil pump 4004.

  Oil pump 4004 is connected to the crankshaft of engine 1000 with torque converter 3200 interposed therebetween. That is, oil pump 4004 is connected to the input shaft of planetary gear unit 3000. When the crankshaft of the engine 1000 is rotated, the oil pump 4004 is driven, the hydraulic oil in the oil pan 4008 is sucked through the distribution path 4014, and is supplied to the hydraulic circuit 4000 to generate hydraulic pressure. . A strainer 4012 is provided at the end of the distribution path 4014 on the oil pan 4008 side.

  The hydraulic pressure generated by the oil pump 4004 is regulated by the primary regulator valve 4006 to generate a line pressure.

  Primary regulator valve 4006 operates using the throttle pressure regulated by SLT 4300 as a pilot pressure. Line pressure is supplied to manual valve 4100 and SL (4) 4240 via line pressure oil passage 4010.

  Manual valve 4100 includes a drain port 4105. From the drain port 4105, the oil pressure in the D range pressure oil passage 4102 and the R range pressure oil passage 4104 is discharged. When the spool of the manual valve 4100 is in a position corresponding to the D range, the line pressure oil passage 4010 and the D range pressure oil passage 4102 are communicated, and the oil pressure is supplied to the D range pressure oil passage 4102. At this time, the R range pressure oil passage 4104 and the drain port 4105 are communicated, and the R range pressure of the R range pressure oil passage 4104 is discharged from the drain port 4105.

  When the spool of the manual valve 4100 is in a position corresponding to the R range, the line pressure oil passage 4010 and the R range pressure oil passage 4104 are communicated, and the oil pressure is supplied to the R range pressure oil passage 4104. At this time, the D-range pressure oil passage 4102 and the drain port 4105 are communicated, and the hydraulic oil in the D-range pressure oil passage 4102 is discharged from the drain port 4105.

  When the spool of the manual valve 4100 is in a position corresponding to the N range, both the D range pressure oil passage 4102 and the R range pressure oil passage 4104 and the drain port 4105 are communicated with each other in the D range pressure oil passage 4102. The working oil and the working oil in the R range pressure oil passage 4104 are discharged from the drain port 4105.

  The oil pressure supplied to the D-range pressure oil passage 4102 passes through the SL (1) 4210, SL (2) 4220, SL (3) 4230, and the oil passage 4106, and finally the B1 brake 3610 and the B2 brake. 3620, C1 clutch 3640 and C2 clutch 3650. The hydraulic pressure supplied to the R range pressure oil passage 4104 is finally supplied to the B2 brake 3620.

  The solenoid modulator valve 4200 adjusts the hydraulic pressure (solenoid modulator pressure) supplied to the SLT 4300 to a constant pressure using the line pressure as the original pressure.

  SL (1) 4210 regulates the hydraulic pressure supplied to the C1 clutch 3640. SL (2) 4220 regulates the hydraulic pressure supplied to C2 clutch 3650. SL (3) 4230 regulates the hydraulic pressure supplied to the B1 brake 3610. SL (4) 4240 regulates the hydraulic pressure supplied to the B3 brake 3630. SL (1) 4210, SL (2) 4220, SL (3) 4230, SL (4) 4240, and SLT 4300 are controlled by a control signal transmitted from ECU 8000.

  The SLT 4300 adjusts the solenoid modulator pressure in accordance with a control signal from the ECU 8000 based on the accelerator opening detected by the accelerator opening sensor 8010, and generates a throttle pressure. The throttle pressure is supplied to the primary regulator valve 4006 via the SLT oil passage 4302. The throttle pressure is used as a pilot pressure for the primary regulator valve 4006.

  The B2 control valve 4500 selectively supplies the hydraulic pressure from one of the D range pressure oil passage 4102 and the R range pressure oil passage 4104 to the B2 brake 3620. A D range pressure oil passage 4102 and an R range pressure oil passage 4104 are connected to the B2 control valve 4500. The B2 control valve 4500 is controlled by the hydraulic pressure supplied from the SL solenoid valve (not shown) and the SLU solenoid valve (not shown) and the biasing force of the spring.

  When the SL solenoid valve is off and the SLU solenoid valve is on, the B2 control valve 4500 is in the state on the left side in FIG. In this case, the B2 brake 3620 is supplied with the hydraulic pressure adjusted from the D range pressure using the hydraulic pressure supplied from the SLU solenoid valve as a pilot pressure.

  When the SL solenoid valve is on and the SLU solenoid valve is off, the B2 control valve 4500 is in the state on the right side in FIG. In this case, the R range pressure is supplied to the B2 brake 3620.

  As shown in FIG. 5, in addition to the configuration of the hydraulic circuit 4000 shown in FIG. 4, the hydraulic circuit 4000 includes a secondary regulator valve 4016, a lockup relay valve 5100, a lockup control valve 5200, and a linear solenoid (SLU). 5300. Lock-up clutch 5600 includes an engagement side oil chamber 5602 and a release side oil chamber 5604.

  ECU 8000 outputs a control signal to linear solenoid (SLU) 5300. ECU 8000 performs slip control (flex lock-up control) on lock-up clutch 5600 based on the engine speed, which is the input speed of torque converter 3200, the turbine speed, the throttle opening, and the vehicle speed.

  The linear solenoid (SLU) 5300 generates a signal pressure that generates an engagement force for the lockup clutch 5600.

  The lock-up control valve 5200 adjusts the pressure difference between the engagement-side oil chamber 5602 and the release-side oil chamber 5604 provided in the torque converter 3200 based on the signal pressure output from the linear solenoid (SLU) 5300 to lock the lock-up clutch. The engagement force is controlled.

  The lock-up relay valve 5100 is connected to the engagement-side oil chamber 5602 or the release-side oil chamber 5604 of the lock-up clutch 5600 so that the engagement force continuously changes until the lock-up clutch 5600 changes from the engaged state to the released state. Supply hydraulic pressure.

  The lockup relay valve 5100 and the lockup control valve 5200 are supplied with the hydraulic pressure regulated by the secondary regulator valve 4016. The secondary regulator valve 4016 is connected to the primary regulator valve 4006, and generates the secondary regulator pressure by regulating the hydraulic oil flowing in from the primary regulator valve 4006 based on the throttle pressure.

  The lockup relay valve 5100 includes a release side port communicating with the release side oil chamber 5604 of the lockup clutch 5600, an engagement side port communicating with the engagement side oil chamber 5602, and an input port supplied with a secondary regulator pressure. Is provided.

  The lockup relay valve 5100 having such a configuration takes a position as an engagement side of the lockup clutch 5600 and a position as a release side of the lockup clutch 5600, respectively. When the lock-up clutch 5600 is engaged, the secondary regulator pressure supplied to the lock-up clutch 5600 is supplied to the engagement-side oil chamber 5602 of the lock-up clutch 5600 as an engagement oil pressure, that is, an on-pressure. At the time of releasing 5600, the secondary regulator pressure is supplied to the release side oil chamber 5604 as a release hydraulic pressure, that is, an off pressure.

  That is, when the off-pressure is supplied to the lock-up clutch 5600, the hydraulic pressure in the release-side oil chamber 5604 of the lock-up clutch 5600 is higher than the hydraulic pressure in the engagement-side oil chamber 5602, and the lock-up clutch 5600 is released. At the same time, the hydraulic oil in the engagement side oil chamber 5602 is discharged to the drain via a discharge port or a check valve.

  On the other hand, when the on-pressure is supplied to the lockup clutch 5600, the hydraulic pressure in the engagement side oil chamber 5602 of the lockup clutch 5600 is made higher than the hydraulic pressure in the release side oil chamber 5604, and the lockup clutch 5600 is engaged. At the same time, the hydraulic oil in the release side oil chamber 5604 is discharged to the drain via the discharge port or the lock-up control valve 5200.

  The linear solenoid (SLU) 5300 generates a slip control signal pressure that increases with the output voltage from the ECU 8000, and causes the slip control signal pressure to act on the lockup control valve 5200.

  The lockup control valve 5200 includes a line pressure port to which a secondary regulator pressure is supplied, a receiving port that receives hydraulic oil in the release oil chamber side of the lockup clutch 5600 discharged from the discharge port of the lockup relay valve 5100, and A drain port for discharging the hydraulic oil received in the receiving port.

  Furthermore, the lock-up control valve 5200 is provided so as to be movable between a first position for communicating between the receiving port and the drain port and a second position for communicating between the receiving port and the line pressure port. Has a spool valve. The spool valve is a force generated by applying a force based on a spring biasing force and a signal pressure for slip control from the linear solenoid (SLU) 5300, a hydraulic pressure supplied to the engagement side oil chamber 5602, and a release side oil. Due to the force generated by applying the hydraulic pressure supplied to the chamber 5604, the chamber 5604 moves to one of the first position and the second position.

  In this lock-up control valve 5200, when the spool valve is in the first position, the receiving port and the drain port are communicated with each other, and the hydraulic oil in the release-side oil chamber 5604 of the lock-up clutch 5600 is discharged to lock. The pressure difference between the hydraulic oil pressure in the engagement side oil chamber 5602 of the up clutch 5600 and the hydraulic oil pressure in the release side oil chamber 5604 is increased.

  On the other hand, in this lockup control valve 5200, when the spool valve is in the second position, the receiving port and the line pressure port are communicated to supply the secondary regulator pressure into the release side oil chamber 5604 of the lockup clutch 5600. As a result, the pressure difference between the hydraulic oil pressure in the engagement-side oil chamber 5602 of the lockup clutch 5600 and the hydraulic oil pressure in the release-side oil chamber 5604 is reduced.

  In this way, the lockup control valve 5200 adjusts the pressure difference between the engagement side oil chamber 5602 and the release side oil chamber 5604 based on the slip control signal pressure output from the linear solenoid (SLU) 5300. The slip amount of the lockup clutch 5600 is controlled. Thereby, the lock-up clutch 5600 is slip-controlled.

  FIG. 6 shows a functional block diagram of ECU 8000 which is a vehicle control apparatus according to the present embodiment.

  ECU 8000 includes an input interface (hereinafter referred to as an input I / F) 300, an arithmetic processing unit 400, a storage unit 500, and an output interface (hereinafter referred to as an output I / F) 600.

  The input I / F 300 includes an oil temperature signal from the oil temperature sensor 8026, a shift position signal from the position switch 8006, a vehicle speed signal from the vehicle speed sensor 8002, an engine speed signal from the engine speed sensor 8020, and a stop. The brake signal from the lamp switch 8014 is received and transmitted to the arithmetic processing unit 400.

  Arithmetic processing unit 400 includes a condition determination unit 402, a timer unit 404, an elapsed time determination unit 406, a rotation speed determination unit 408, a brake determination unit 410, and a lockup clutch control unit 412.

  The condition determination unit 402 determines whether the shift position of the automatic transmission 2000 is the D position and the vehicle speed is zero. The condition determination unit 402 determines whether or not the shift position is the D position based on the shift position signal. Furthermore, the condition determination unit 402 determines whether or not the vehicle speed is zero based on the vehicle speed signal. For example, the condition determination unit 402 may turn on the condition establishment flag when the vehicle is at the D position and the vehicle speed is zero.

  The timer unit 404 activates the timer when the condition determination unit 402 determines that the vehicle is at the D position and the vehicle speed is zero. That is, the timer unit 404 measures the elapsed time Td by resetting the count value to the initial value and adding a predetermined count value for each calculation cycle. Note that the timer unit 404 may start the timer when the condition establishment flag is turned on, for example.

  The elapsed time determination unit 406 determines whether or not the elapsed time Td measured by the timer unit 404 is equal to or greater than a predetermined time T (0). Note that the elapsed time determination unit 406 may turn on the elapsed time determination flag when the measured elapsed time Td is equal to or greater than a predetermined time T (0).

  The rotational speed determination unit 408 determines whether or not the engine rotational speed NE is equal to or higher than the reference rotational speed NE (0) based on the engine rotational speed signal. The rotational speed determination unit 408 sets the reference rotational speed NE (0) based on the state of the engine 1000 and the automatic transmission 2000. For example, the engine speed determination unit 408 uses the map as a reference engine speed NE (0) based on the fuel injection amount, the coolant temperature of the engine 1000, the oil temperature of the engine 1000, the oil temperature and the air temperature of the automatic transmission 2000, and the like. May be set. Note that, for example, the engine speed determination unit 408 may turn on the engine speed determination flag when the engine speed NE is equal to or higher than the reference engine speed NE (0).

  The brake determination unit 410 determines whether or not the brake pedal 8012 is turned on based on the brake signal from the stop lamp switch 8014. For example, if the brake determination unit 410 does not receive a brake signal, the brake determination unit 410 determines that the brake pedal 8012 is turned off (depression is released). For example, the brake determination unit 410 may turn on the brake determination flag when the brake pedal 8012 is turned on (depressed) and turn off the brake determination flag when the brake pedal 8012 is turned off.

  When the torque converter 3200 is in the lost drive state (that is, the lock-up clutch control unit 412 has a predetermined time T (0) from when the shift position is the D position and the vehicle speed becomes zero). When the engine speed NE is equal to or higher than the reference speed NE (0) after the passage of time), when the brake pedal 8012 is turned off, the control signal is applied so that the lockup clutch 5600 is engaged according to the state of the vehicle. Is transmitted to the linear solenoid (SLU) 5300 via the output I / F 600. For example, the lock-up clutch control unit 412 controls the lock-up clutch 5600 so that a predetermined creep force is exerted on the drive wheels. Unless the accelerator pedal 8008 is depressed, the lock-up clutch control unit 412 locks the clutch 5600 so that a predetermined vehicle speed, a predetermined engine speed, or a predetermined driving torque is generated. May be feedback controlled. Further, when the brake pedal 8012 is depressed while the vehicle is stopped, the lockup clutch control unit 412 cancels the direct connection state of the lockup clutch 5600 and sets the release state.

  Note that the lockup clutch control unit 412 may control the lockup clutch 5600, for example, when the rotation speed determination flag is on and the brake determination flag is off.

  In the present embodiment, condition determination unit 402, timer unit 404, elapsed time determination unit 406, rotation speed determination unit 408, brake determination unit 410, and lockup clutch control unit 412 are all arithmetic processing units. Although the description will be made assuming that (Central Processing Unit) functions as software realized by executing a program stored in storage unit 500, it may be realized by hardware. Such a program is recorded on a recording medium and mounted on the vehicle.

  Hereinafter, with reference to FIG. 7, a control structure of a program executed by ECU 8000 which is the vehicle control apparatus according to the present embodiment will be described.

  In step (hereinafter, step is referred to as S) 100, ECU 8000 determines whether or not the shift position is the D position and the vehicle speed is zero. If it is in the D position and the vehicle speed is zero (YES in S100), the process proceeds to S102. If not (NO in S100), the process returns to S100.

  In S102, ECU 8000 starts a timer and measures elapsed time Td. In S104, ECU 8000 determines whether or not elapsed time Td is equal to or longer than a predetermined time T (0). If elapsed time Td is equal to or longer than predetermined time T (0) (YES in S104), the process proceeds to S106. If not (NO in S104), the process returns to S104.

  In S106, ECU 8000 obtains engine speed NE. In S108, ECU 8000 determines whether or not acquired engine speed NE is equal to or higher than reference speed NE (0). If engine speed NE is equal to or higher than reference speed NE (0) (YES in S108), the process proceeds to S110. If not (NO in S108), the process returns to S106.

  In S110, ECU 8000 determines whether or not the brake is turned off. If the brake is turned off (YES in S110), the process proceeds to S112. If not (NO in S110), the process returns to S106. In S112, lock-up clutch control is executed according to the state of the vehicle.

  The operation of ECU 8000 serving as the vehicle control apparatus according to the present embodiment based on the above-described structure and flowchart will be described with reference to FIG.

  For example, it is assumed that the vehicle is stopped with the P position or the N position selected as the shift position. Further, it is assumed that the engine speed NE is NE (1) higher than NE (0).

  At time T (1), when the driver depresses the brake pedal 8012 and operates the shift lever 8004 to change the shift position to the D position, the C1 clutch 3640 is engaged and the first gear is formed. Is done. Therefore, output torque TO (0) is generated in automatic transmission 2000. The power of the engine 1000 is used to rotate the pump impeller. Since the turbine runner does not rotate when the vehicle stops, the torque converter 3200 slips. Therefore, the rotational speed of engine 1000 decreases from NE (1) due to the reaction force of torque converter 3200. Since the vehicle is stopped, the vehicle speed is zero. Therefore, when the shift position is changed to the D position (YES in S100), a timer is started (S102).

  When a predetermined time T (0) elapses from time T (1) at time T (2) (YES in S104), engine speed NE is acquired (S106), and the acquired engine speed is acquired. It is determined whether or not the number NE is greater than or equal to a reference rotational speed NE (0) set according to the engine 1000 and the automatic transmission 2000 (S108).

  At time T (3), when the state of the torque converter 3200 becomes a lost drive state in which the power transmission capability is reduced due to the bubbles of hydraulic oil being retained or accumulated in the torque converter 3200, the engine speed NE increases. At the same time, the output torque TO of the automatic transmission 2000 decreases from TO (0).

  When engine speed NE becomes equal to or higher than reference speed NE (0) at time T (4) (YES in S108), it is determined whether or not the brake is turned off (S110). After the time T (4), when the decrease in power transmission capability of the torque converter 3200 converges, the engine speed NE and the output torque TO become substantially constant.

  When the driver releases the depression of brake pedal 8012 at time T (5) (YES in S110), creep force is developed and the vehicle starts to move. Along with the release of the brake pedal 8012, lock-up clutch control is executed (S112). As the engagement force of the lockup clutch 5600 increases, the degree of transmission of power from the engine 1000 to the drive wheels increases, so the output torque TO increases. Further, the engine speed NE decreases due to a reaction force from the road surface.

  As described above, according to the vehicle control apparatus of the present embodiment, when the vehicle is stopped, when the state of the speed change mechanism is a state in which the engine power is transmitted to the drive wheels, the engine speed NE. Can be determined that the torque converter is in the lost drive state and the power transmission capability is reduced. Therefore, when it is determined that the torque converter is in the lost drive state, by controlling the lock-up clutch so that the degree of engagement of the lock-up clutch is increased when the vehicle is started, Since power transmission to the output shaft is assisted by engagement of the lockup clutch, it is possible to suppress a decrease in power transmission capability of the torque converter. Therefore, the vehicle can be moved according to the driver's intention. Therefore, it is possible to provide a vehicle control device and a control method that suppress a decrease in power transmission capability of the torque converter caused by air mixed into the hydraulic oil.

  Further, after a shift time is changed to the D position and a predetermined time T (0) when the fluctuation of the engine speed NE converges after it is determined that the vehicle speed is zero, the engine speed NE is increased. Can be accurately determined whether or not the torque converter is in the lost drive state by determining whether or not is greater than or equal to the reference rotational speed NE (0).

  In the present embodiment, the engine rotational speed NE is changed to the reference rotational speed after a predetermined time T (0) has elapsed after the shift position is changed to the D position and the vehicle speed is determined to be zero. Although it has been described that the lockup clutch is controlled when the determination condition of NE (0) or higher is satisfied, for example, as the determination condition, the temperature of the hydraulic oil of the automatic transmission based on the oil temperature signal is determined in advance. You may make it add the conditions that it is below a certain temperature. In this way, it can be accurately determined whether or not the torque converter is in a lost drive state.

<Second Embodiment>
Hereinafter, the vehicle control apparatus according to the second embodiment will be described. The vehicle control apparatus according to the present embodiment is executed by ECU 8000 and the operation of rotation speed determination unit 408 shown in FIG. 6 as compared with the configuration of the vehicle control apparatus according to the first embodiment described above. The program control structure is different. The rest of the configuration is the same as the configuration of the vehicle control device according to the first embodiment described above. They are given the same reference numerals. Their functions are the same. Therefore, detailed description thereof will not be repeated here.

  In the present embodiment, ECU 8000 provides a reference based on engine speed NE when a predetermined time T (0) has elapsed since the shift position is the D position and the vehicle speed becomes zero. A feature is that the lockup clutch is controlled when the engine speed NE (0) is set and the engine speed NE is equal to or higher than the set reference engine speed NE (0).

  The rotation speed determination unit 408 shown in FIG. 6 sets the reference rotation speed NE (0) based on the engine rotation speed signal. Specifically, the rotational speed determination unit 408 sets a value obtained by adding a predetermined value α to the detected engine rotational speed NE as the reference rotational speed NE (0). The predetermined value α is not particularly limited as long as it can determine the lost drive state of the torque converter 3200, and is a value that is adapted by experiments or the like. Further, the rotational speed determination unit 408 determines whether or not the engine rotational speed NE is equal to or higher than the reference rotational speed NE (0). Note that, for example, the engine speed determination unit 408 may turn on the engine speed determination flag when the engine speed NE is equal to or higher than the reference engine speed NE (0).

  Hereinafter, with reference to FIG. 9, a control structure of a program executed by ECU 8000 which is the vehicle control apparatus according to the present embodiment will be described.

  In the flowchart shown in FIG. 9, the same steps as those in the flowchart shown in FIG. 7 are given the same step numbers. The processing for them is the same. Therefore, detailed description thereof will not be repeated here.

  When engine speed NE is acquired at S106, ECU 8000 calculates a reference speed NE (0) by adding a predetermined value α to the acquired engine speed NE at S200. In S202, ECU 8000 obtains engine speed NE. Thereafter, the process proceeds to S108.

  The operation of ECU 8000 serving as the vehicle control apparatus according to the present embodiment based on the above-described structure and flowchart will be described.

  For example, it is assumed that the vehicle is stopped with the P position or the N position selected as the shift position. The engine speed NE is assumed to be NE (1) higher than NE (0).

  When the driver depresses the brake pedal 8012 and operates the shift lever 8004 to change the shift position to the D position, the C1 clutch 3640 is engaged and the first gear is formed. Therefore, output torque TO (0) is generated in automatic transmission 2000. The power of the engine 1000 is used to rotate the pump impeller. Further, since the turbine runner does not rotate, slip occurs in the torque converter 3200. Therefore, the rotational speed of engine 1000 decreases from NE (1) due to the reaction force of torque converter 3200. Since the vehicle is stopped, the vehicle speed is zero. Therefore, when the shift position is changed to the D position (YES in S100), a timer is started (S102).

  When a predetermined time T (0) has elapsed since the timer was started (YES in S104), engine speed NE is acquired (S106). A reference value NE (0) is set by adding a predetermined value α to the acquired engine speed NE (S200). Further, the engine speed NE is acquired (S202), and it is determined whether or not the acquired engine speed NE is equal to or higher than the reference speed NE (0) (S108).

  When the torque converter 3200 is in the lost drive state, the power transmission capability of the torque converter 3200 is reduced, so that the engine speed NE is increased and the output torque TO of the automatic transmission 2000 is decreased from TO (0). Go.

  When engine speed NE is equal to or higher than reference speed NE (0) (YES in S108), it is determined whether or not the brake is turned off (S110). When the decrease in the power transmission capability of torque converter 3200 converges, engine speed NE and output torque TO become substantially constant.

  When the driver releases the depression of brake pedal 8012 (YES in S110), creep force is developed and the vehicle starts to move. Along with the release of the brake pedal 8012, the lockup clutch 5600 is controlled according to the state of the vehicle (S112). As the engagement force of the lockup clutch 5600 increases, the degree of transmission of power from the engine 1000 to the drive wheels increases, so the output torque TO increases. Further, the engine speed NE decreases due to a reaction force from the road surface.

  As described above, according to the vehicle control device of the present embodiment, the same effect as that obtained by the operation of the vehicle control device of the first embodiment described above can be obtained.

<Third Embodiment>
Hereinafter, the vehicle control apparatus according to the third embodiment will be described. Compared with the configuration of the vehicle control device according to the first embodiment described above, the vehicle control device according to the present embodiment is executed by the operation of lock-up clutch control unit 412 shown in FIG. The program control structure differs. The rest of the configuration is the same as the configuration of the vehicle control device according to the first embodiment described above. They are given the same reference numerals. Their functions are the same. Therefore, detailed description thereof will not be repeated here.

  In the present embodiment, ECU 8000 determines that engine speed NE is equal to that of engine 1000 when the shift position is the D position and a predetermined time T (0) has elapsed from the time when the vehicle speed becomes zero. A feature is that the lockup clutch 5600 is controlled so that the engine rotational speed NE becomes the reference rotational speed NE (0) when the reference rotational speed NE (0) or more set according to the state of the automatic transmission 2000 is reached. Have.

  The lockup clutch control unit 412 shown in FIG. 6 determines that the engine speed NE is the reference after a predetermined time T (0) has elapsed since the shift position is the D position and the vehicle speed becomes zero. When it is equal to or higher than the rotational speed NE (0), the lockup clutch 5600 is controlled using the reference rotational speed NE (0) as the target rotational speed. That is, the lockup clutch control unit 412 increases the engagement force of the lockup clutch 5600 so that the engine speed NE that has risen above the reference speed NE (0) decreases to the reference speed NE (0). The lockup clutch control unit 412 generates a control signal so that the engagement force of the lockup clutch 5600 is increased, and transmits the control signal to the linear solenoid (SLU) 5300 via the output I / F 600. Note that the lockup clutch control unit 412, for example, locks the clutch so that the engine rotational speed NE becomes the reference rotational speed NE (0) when the rotational speed determination flag is on and the brake determination flag is on. The 5600 may be controlled.

  Further, the lockup clutch control unit 412 controls the lockup clutch 5600 so that the engagement force increases in accordance with the state of the vehicle so that a predetermined creep force is generated when the brake is turned off.

  Hereinafter, with reference to FIG. 10, a control structure of a program executed by ECU 8000 which is the vehicle control apparatus according to the present embodiment will be described.

  In the flowchart shown in FIG. 10, the same steps as those in the flowchart shown in FIG. The processing for them is the same. Therefore, detailed description thereof will not be repeated here.

  If it is determined at S108 that engine speed NE is greater than or equal to reference speed NE (0), ECU 8000 determines whether or not the brake is turned off at S300. If the brake is turned off (YES in S300), the process proceeds to S112. If not (NO in S300), the process proceeds to S302.

  In S302, ECU 8000 performs feedback control on the engagement force of lockup clutch 5600 with reference rotation speed NE (0) as the target rotation speed. In S304, ECU 8000 determines whether or not the brake is turned off. If the brake is turned off (YES in S304), the process proceeds to S112. If not (NO in S304), the process returns to S302.

  The operation of ECU 8000 serving as the vehicle control apparatus according to the present embodiment based on the above-described structure and flowchart will be described.

  For example, it is assumed that the vehicle is stopped with the P position or the N position selected as the shift position. The engine speed NE is assumed to be NE (1) higher than NE (0).

  When the driver depresses the brake pedal 8012 and operates the shift lever 8004 to change the shift position to the D position, the C1 clutch 3640 is engaged and the first gear is formed. Therefore, output torque TO (0) is generated in automatic transmission 2000. The power of the engine 1000 is used to rotate the pump impeller. Further, since the turbine runner does not rotate, slip occurs in the torque converter 3200. Therefore, the rotational speed of engine 1000 decreases from NE (1) due to the reaction force of torque converter 3200. Since the vehicle is stopped, the vehicle speed is zero. Therefore, when the shift position is changed to the D position (YES in S100), a timer is started (S102).

  When a predetermined time T (0) has elapsed since the timer was started (YES in S104), engine speed NE is acquired (S106), and the acquired engine speed NE is set to engine 1000 and automatic transmission. It is determined whether or not the rotational speed is equal to or higher than the reference rotational speed NE (0) set according to the state of the machine 2000 (S108).

  When the torque converter 3200 is in the lost drive state, the power transmission capability of the torque converter 3200 is reduced, so that the engine speed NE is increased and the output torque TO of the automatic transmission 2000 is decreased from TO (0). Go.

  When engine speed NE is equal to or higher than reference speed NE (0) (YES in S108), it is determined whether or not the brake is turned off (S300). When the decrease in the power transmission capability of torque converter 3200 converges, engine speed NE and output torque TO become substantially constant.

  If the driver continues to depress brake pedal 8012 (NO in S300), lock-up clutch 5600 is controlled with reference rotational speed NE (0) as the target rotational speed. Control of the engagement force of the lockup clutch 5600 with the reference rotation speed NE (0) as the target rotation speed is continued as long as the driver depresses the brake pedal 8012. As the engagement force of the lock-up clutch 5600 increases, frictional heat due to the slip generated in the lock-up clutch 5600 is generated. Therefore, the automatic transmission 2000 is warmed up by the generated frictional heat. When the temperature of the hydraulic oil rises due to warm-up, the viscosity of the hydraulic oil decreases, so the lost drive state of the torque converter 3200 improves with time.

  When the driver releases the depression of brake pedal 8012 (YES in S304), creep force is developed and the vehicle starts to move. Along with the release of the brake pedal 8012, the lockup clutch 5600 is controlled according to the state of the vehicle (S112). As the engagement force of the lockup clutch 5600 increases, the degree of transmission of power from the engine 1000 to the drive wheels increases, so the output torque TO increases. Further, the engine speed NE decreases due to a reaction force from the road surface.

  As described above, according to the vehicle control apparatus according to the present embodiment, in addition to the effects that are manifested by the operation of the vehicle control apparatus according to the first embodiment described above, the lockup is performed while the vehicle is stopped. Since the clutch 5600 is controlled so that the engagement force increases from the state in which the direct connection state is eliminated, frictional heat is generated by slipping of the friction engagement element, and warming up of the automatic transmission 2000 is promoted, and the lost drive state Can be improved.

<Fourth embodiment>
A vehicle control apparatus according to the fourth embodiment will be described below. Compared with the configuration of the vehicle control device according to the first embodiment described above, the vehicle control device according to the present embodiment includes rotation speed determination unit 408 and lockup clutch control unit 412 shown in FIG. The operation and the control structure of the program executed by ECU 8000 are different. The rest of the configuration is the same as the configuration of the vehicle control device according to the first embodiment described above. They are given the same reference numerals. Their functions are the same. Therefore, detailed description thereof will not be repeated here.

  In the present embodiment, ECU 8000 provides a reference based on engine speed NE when a predetermined time T (0) has elapsed since the shift position is the D position and the vehicle speed becomes zero. When the engine speed NE (0) is set and the engine speed NE becomes equal to or higher than the set reference engine speed NE (0), the lockup clutch 5600 is set so that the engine engine speed NE becomes the reference engine speed NE (0). It has a feature in that it controls.

  The rotation speed determination unit 408 shown in FIG. 6 sets the reference rotation speed NE (0) based on the engine rotation speed signal. Specifically, the rotational speed determination unit 408 sets a value obtained by adding a predetermined value α to the detected engine rotational speed NE as the reference rotational speed NE (0). The predetermined value α is not particularly limited as long as it can determine the lost drive state of the torque converter 3200, and is a value that is adapted by experiments or the like. Further, the rotational speed determination unit 408 determines whether or not the engine rotational speed NE is equal to or higher than the reference rotational speed NE (0). Note that, for example, the engine speed determination unit 408 may turn on the engine speed determination flag when the engine speed NE is equal to or higher than the reference engine speed NE (0).

  The lockup clutch control unit 412 shown in FIG. 6 determines that the engine speed NE is the reference after a predetermined time T (0) has elapsed since the shift position is the D position and the vehicle speed becomes zero. When it is equal to or higher than the rotational speed NE (0), the lockup clutch 5600 is controlled using the reference rotational speed NE (0) as the target rotational speed. In other words, the lock-up clutch control unit 412 increases the engagement force of the lock-up clutch 5600 so that the engine speed NE that has risen above the reference speed NE80) decreases to the reference speed NE (0). The lockup clutch control unit 412 generates a control signal so that the engagement force of the lockup clutch 5600 is increased, and transmits the control signal to the linear solenoid (SLU) 5300 via the output I / F 600. Note that the lockup clutch control unit 412, for example, locks the clutch so that the engine rotational speed NE becomes the reference rotational speed NE (0) when the rotational speed determination flag is on and the brake determination flag is on. The 5600 may be controlled.

  Further, the lockup clutch control unit 412 controls the lockup clutch 5600 to increase the engagement force according to the state of the vehicle so that a predetermined creep force is generated when the brake is turned off.

  Hereinafter, with reference to FIG. 11, a control structure of a program executed by ECU 8000 which is the vehicle control apparatus according to the present embodiment will be described.

  In the flowchart shown in FIG. 11, the same steps as those in the flowchart shown in FIG. 7 are given the same step numbers. The processing for them is the same. Therefore, detailed description thereof will not be repeated here.

  When engine speed NE is acquired in S106, ECU 8000 calculates a reference speed NE (0) by adding a predetermined value α to the acquired engine speed NE in S400. In S402, ECU 8000 obtains engine speed NE.

  In S404, ECU 8000 determines whether or not engine speed NE is equal to or higher than calculated reference speed NE (0). If engine speed NE is equal to or higher than reference speed NE (0) (YES in S404), the process proceeds to S406. If not (NO in S404), the process returns to S402.

  In S406, ECU 8000 determines whether or not the brake is turned off. If the brake is turned off (YES in S406), the process proceeds to S112. If not (NO in S406), the process proceeds to S408.

  In S408, ECU 8000 performs feedback control on the engagement force of lockup clutch 5600 with reference rotation speed NE (0) as the target rotation speed. In S410, ECU 8000 determines whether or not the brake is turned off. If the brake is turned off (YES in S410), the process proceeds to S112. If not (NO in S410), the process returns to S408.

  The operation of ECU 8000 serving as the vehicle control apparatus according to the present embodiment based on the above-described structure and flowchart will be described.

  For example, it is assumed that the vehicle is stopped with the P position or the N position selected as the shift position. The engine speed NE is assumed to be NE (1) higher than NE (0).

  When the driver depresses the brake pedal 8012 and operates the shift lever 8004 to change the shift position to the D position, the C1 clutch 3640 is engaged and the first gear is formed. Therefore, output torque TO (0) is generated in automatic transmission 2000. The power of the engine 1000 is used to rotate the pump impeller. Further, since the turbine runner does not rotate, slip occurs in the torque converter 3200. Therefore, the rotational speed of engine 1000 decreases from NE (1) due to the reaction force of torque converter 3200. Since the vehicle is stopped, the vehicle speed is zero. Therefore, when the shift position is changed to the D position (YES in S100), a timer is started (S102).

  When a predetermined time T (0) has elapsed since the timer was started (YES in S104), engine speed NE is acquired (S106). A reference value NE (0) is set by adding a predetermined value α to the acquired engine speed NE (S400). Further, the engine speed NE is acquired (S402), and it is determined whether or not the acquired engine speed NE is equal to or higher than the reference speed NE (0) (S404).

  When the torque converter 3200 is in the lost drive state, the power transmission capability of the torque converter 3200 is reduced, so that the engine speed NE is increased and the output torque TO of the automatic transmission 2000 is decreased from TO (0). Go.

  If the engine speed is equal to or higher than the reference speed NE (0) (YES in S404), it is determined whether or not the brake is turned off (S406). When the decrease in the power transmission capability of torque converter 3200 converges, engine speed NE and output torque TO become substantially constant.

  If the driver continues to depress brake pedal 8012 (NO in S406), lock-up clutch 5600 is controlled using reference rotational speed NE (0) as the target rotational speed. Control of the engagement force of the lockup clutch 5600 with the reference rotation speed NE (0) as the target rotation speed is continued as long as the driver depresses the brake pedal 8012. As the engagement force of the lock-up clutch 5600 increases, frictional heat due to the slip generated in the lock-up clutch 5600 is generated. Therefore, the automatic transmission 2000 is warmed up by the generated frictional heat. When the temperature of the hydraulic oil rises due to warm-up, the viscosity of the hydraulic oil decreases, so the lost drive state of the torque converter 3200 improves with time.

  When the driver releases the depression of brake pedal 8012 (YES in S410), creep force is developed and the vehicle starts to move. Along with the release of the brake pedal 8012, the lockup clutch 5600 is controlled according to the state of the vehicle (S112). As the engagement force of the lockup clutch 5600 increases, the degree of transmission of power from the engine 1000 to the drive wheels increases, so the output torque TO increases. Further, the engine speed NE decreases due to a reaction force from the road surface.

  As described above, according to the vehicle control apparatus according to the present embodiment, in addition to the effects that are manifested by the operation of the vehicle control apparatus according to the first embodiment described above, the lockup is performed while the vehicle is stopped. Since the clutch 5600 is controlled so that the engagement force increases from the state in which the direct connection state is eliminated, frictional heat is generated by slipping of the friction engagement element, and warming up of the automatic transmission 2000 is promoted, and the lost drive state Can be improved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram which shows the power train controlled by ECU which is the control apparatus of the vehicle which concerns on 1st Embodiment. It is a skeleton figure which shows the gear train of an automatic transmission. It is a figure which shows the action | operation table | surface of an automatic transmission. FIG. 3 is a first diagram illustrating a part of a hydraulic circuit of an automatic transmission. FIG. 6 is a second diagram illustrating a part of a hydraulic circuit of the automatic transmission. It is a functional block diagram of ECU which is a control device of vehicles concerning a 1st embodiment. It is a flowchart which shows the control structure of the program performed with ECU which is the control apparatus of the vehicle which concerns on 1st Embodiment. It is a timing chart which shows operation of ECU which is a control device of vehicles concerning a 1st embodiment. It is a flowchart which shows the control structure of the program performed with ECU which is the control apparatus of the vehicle which concerns on 2nd Embodiment. It is a flowchart which shows the control structure of the program performed with ECU which is the control apparatus of the vehicle which concerns on 3rd Embodiment. It is a flowchart which shows the control structure of the program performed with ECU which is the control apparatus of the vehicle which concerns on 4th Embodiment.

Explanation of symbols

  300 input I / F, 400 arithmetic processing unit, 402 condition determination unit, 404 timer unit, 406 elapsed time determination unit, 408 rotation speed determination unit, 410 brake determination unit, 412 lockup clutch control unit, 500 storage unit, 600 output I / F, 1000 engine, 2000 automatic transmission, 3000 planetary gear unit, 3100 input shaft, 3200 torque converter, 3210 output shaft, 3610 B1 brake, 3620 B2 brake, 3630 B3 brake, 3640 C1 clutch, 3650 C2 clutch, 4000 hydraulic pressure Circuit, 4004 oil pump, 4006 primary regulator valve, 4008 oil pan, 4012 strainer, 4014 flow path, 4016 secondary regulator valve, 4100 manual Al valve, 4200 solenoid modulator valve, 4500 B2 control valve, 5000 differential gear, 5100 lockup relay valve, 5200 lockup control valve, 5600 lockup clutch, 5602 engagement side oil chamber, 5604 release side oil chamber, 6000 drive shaft, 7000 front wheel, 8002 vehicle speed sensor, 8004 shift lever, 8006 position switch, 8008 accelerator pedal, 8010 accelerator opening sensor, 8012 brake pedal, 8014 stop lamp switch, 8016 electronic throttle valve, 8018 throttle opening sensor, 8020 engine speed sensor 8022 Input shaft speed sensor 8024 Output shaft speed sensor 8026 Oil temperature sensor Nsa.

Claims (12)

A control device for a vehicle, wherein the vehicle includes an engine, an automatic transmission connected to the engine, and driving wheels to which power of the engine is transmitted via the automatic transmission. The transmission includes a torque converter connected to the engine, a lockup clutch provided in the torque converter, and a transmission mechanism connected to the torque converter, and the lockup clutch is engaged. Thus, the input shaft and the output shaft of the torque converter are brought into a direct connection state, and the direct connection state is canceled by releasing,
Detecting means for detecting the rotational speed of the engine;
The first condition that the state of the transmission mechanism is a state in which the power of the engine is transmitted to the drive wheels while the vehicle is stopped, and the rotational speed of the engine corresponds to the state of the transmission mechanism. When a determination condition including a second condition that the engine speed is equal to or higher than a reference rotational speed is satisfied, it is determined that the state of the torque converter is a lost drive state in which a power transmission capability from the engine to the transmission mechanism is reduced. Determination means for,
And a control unit for controlling the lockup clutch so as to suppress a decrease in the power transmission capability in accordance with the state of the vehicle when it is determined that the lost drive state is established. .   2. The vehicle control device according to claim 1, wherein the determination unit determines whether or not the second condition is satisfied after a predetermined time has elapsed since the first condition is satisfied. . The control means includes
Means for eliminating the directly connected state of the lock-up clutch while the vehicle is stopped;
Means for controlling the lockup clutch so that the degree of engagement of the lockup clutch increases when the vehicle starts when it is determined that the state of the torque converter is the lost drive state The vehicle control device according to claim 1, comprising:   The said control means controls the said lockup clutch so that the rotation speed of the said engine may become the said reference rotation speed, when it determines with the state of the said torque converter being the said lost drive state. 4. The vehicle control device according to any one of 3.   The vehicle control device according to any one of claims 1 to 4, wherein the control device further includes setting means for setting the reference rotational speed based on states of the engine and the automatic transmission.   The vehicle control device according to claim 1, wherein the determination condition further includes a condition that a temperature of hydraulic oil of the automatic transmission is equal to or lower than a predetermined temperature. A vehicle control method, wherein the vehicle includes an engine, an automatic transmission connected to the engine, and driving wheels to which power of the engine is transmitted via the automatic transmission. The transmission includes a torque converter connected to the engine, a lockup clutch provided in the torque converter, and a transmission mechanism connected to the torque converter, and the lockup clutch is engaged. Thus, the input shaft and the output shaft of the torque converter are brought into a direct connection state, and the direct connection state is canceled by releasing,
A detection step of detecting the rotational speed of the engine;
The first condition that the state of the transmission mechanism is a state in which the power of the engine is transmitted to the drive wheels while the vehicle is stopped, and the rotational speed of the engine corresponds to the state of the transmission mechanism. When a determination condition including a second condition that the engine speed is equal to or higher than a reference rotational speed is satisfied, it is determined that the state of the torque converter is a lost drive state in which a power transmission capability from the engine to the transmission mechanism is reduced. A determination step;
And a control step of controlling a lock-up clutch so as to suppress a decrease in the power transmission capability in accordance with the state of the vehicle when it is determined that the lost drive state is set.   The vehicle control method according to claim 7, wherein the determining step determines whether or not the second condition is satisfied after a predetermined time has elapsed since the first condition is satisfied. . The control step includes
Canceling the directly connected state of the lock-up clutch while the vehicle is stopped;
Controlling the lock-up clutch so that the degree of engagement of the lock-up clutch is increased when the vehicle is started when it is determined that the torque converter is in the lost drive state. The vehicle control method according to claim 7 or 8, further comprising:   The said control step controls the said lockup clutch so that the rotation speed of the said engine may become the said reference rotation speed, when it determines with the state of the said torque converter being the said lost drive state. The vehicle control method according to claim 9.   The vehicle control method according to claim 7, wherein the control method further includes a setting step of setting the reference rotational speed based on states of the engine and the automatic transmission.   The vehicle control method according to claim 7, wherein the determination condition further includes a condition that a temperature of hydraulic oil of the automatic transmission is equal to or lower than a predetermined temperature.

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