JP4830718B2 - Control device for automatic transmission - Google Patents

Description

  The present invention relates to a control device for an automatic transmission, and more particularly to a technique for controlling an automatic transmission in which a plurality of gear stages are formed by selectively engaging a plurality of friction engagement elements.

  Conventionally, a vehicle equipped with an automatic transmission in which a plurality of gear stages are formed by selectively engaging a plurality of friction engagement elements is known. In such a vehicle, generally, a desired gear stage is formed by engaging two friction engagement elements. By the way, for example, in order to smoothly shift from the first gear to the second gear, when the first gear is formed, a one-way clutch is engaged instead of a friction engagement element such as a clutch or a brake. There is something. In such an automatic transmission, a first gear is formed by engaging a one-way clutch when the vehicle is driven. For example, when the vehicle is braked by engine braking, a first gear is formed by engaging a friction engagement element provided in parallel with the one-way clutch.

  By the way, even when the vehicle is driven, the one-way clutch is not always engaged. For example, if the temperature of the hydraulic oil for the automatic transmission (hereinafter also referred to as oil temperature) is low, the one-way clutch may not be engaged due to the high viscosity. Therefore, a technique has been proposed in which a first gear is forcibly formed by engaging a friction engagement element provided in parallel with the one-way clutch at a low oil temperature where the one-way clutch may not be engaged. .

  JP 2006-183705 A (Patent Document 1) discloses a power transmission path disposed between an input member and an output member, a plurality of friction engagement elements capable of selectively switching the power transmission path, A power transmission path having a one-way clutch engaged at the first forward speed, and selectively engaging a friction engagement element to transmit power between the forward range constituting the forward speed and the input / output member. Disclosed is a shift control device for an automatic transmission that can be switched to a neutral range to be shut off. The transmission control device described in Patent Document 1 includes a temperature detection unit that detects the oil temperature of the one-way clutch portion or a temperature related to the oil temperature, and a switching detection unit that detects that the neutral range is switched to the forward range. When the temperature detected by the oil temperature detection unit is not more than a predetermined value and the switching detection unit detects that the temperature is switched from the neutral range to the forward range, the one-way clutch is mechanically connected and the first forward speed And a control unit that engages frictional engagement elements that do not need to be engaged in a stage until a predetermined release condition is satisfied.

According to the speed change control device described in this publication, when the oil temperature of the one-way clutch portion or the temperature related to the oil temperature is equal to or lower than a predetermined value and is switched from the neutral range to the forward range, And the frictional engagement elements that do not need to be engaged in the first forward speed are engaged until a predetermined release condition is satisfied. As a result, the function of the one-way clutch can be replaced with a friction engagement element that does not need to be engaged. For this reason, when the roller type one-way clutch is employed, even if the roller cannot block the lubricating oil having a high viscosity at a low temperature and the lock function is lost, the start can be surely performed.
JP 2006-183705 A

  By the way, since the viscosity of the hydraulic oil is high at the time of low oil temperature, even if the first gear is formed, the gear ratio is lower than the first gear (for example, the second gear). The frictional engagement elements engaged to form the torque may transmit torque. In this case, the one-way clutch cannot be engaged, and the gear ratio becomes lower than the gear ratio of the first gear. As a result, the driving force decreases. As a result, the acceleration performance deteriorates. However, the shift control device described in Japanese Patent Application Laid-Open No. 2006-183705 only engages a friction engagement element provided in parallel with the one-way clutch when the oil temperature is low. Therefore, no consideration is given to deterioration in acceleration due to the frictional engagement element that should originally be in the released state transmitting torque.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device for an automatic transmission that can suppress deterioration in acceleration performance.

  According to a first aspect of the present invention, there is provided a control device for an automatic transmission, wherein the first friction engagement element that is operated by the pressure of the hydraulic oil is in a released state and is operated by the pressure of the hydraulic oil. The first gear stage is formed when the first friction engagement element is in the engagement state and the second friction engagement element is in the release state. A control device for an automatic transmission in which a second gear is formed when the engagement element is in a released state and the second friction engagement element is in an engaged state. The control device is controlled so that the temperature of the hydraulic oil is detected, the first friction engagement element is in a released state, and the second friction engagement element is in a released state. And determining means for determining whether or not the gear ratio of the automatic transmission is changed by the second friction engagement element, and the first friction engagement element is in the released state. And the second frictional engagement element is controlled to be in the released state, and the temperature is equal to or lower than a predetermined temperature and the gear of the automatic transmission is driven by the second frictional engagement element. Control means for controlling the first frictional engagement element to be in the engaged state when it is determined that the ratio is changed.

  According to the first invention, when the first friction engagement element that is operated by the pressure of the hydraulic oil is in a released state, and the second friction engagement element that is operated by the pressure of the hydraulic oil is in a released state; The first gear stage is formed when the first friction engagement element is in the engaged state and the second friction engagement element is in the released state. The second gear stage is formed when the first friction engagement element is in the released state and the second friction engagement element is in the engagement state. Therefore, when the first frictional engagement element is controlled to be in the released state and the second frictional engagement element is controlled to be in the released state, the viscosity becomes higher at the low oil temperature and the second When the frictional engagement element transmits torque, the gear ratio of the automatic transmission can change. In this case, when the gear ratio decreases, the driving force of the vehicle decreases and the acceleration performance deteriorates. Therefore, the temperature of the hydraulic oil is detected. When the first frictional engagement element is controlled to be in a released state and the second frictional engagement element is controlled to be in a released state, the gear ratio of the automatic transmission is controlled by the second frictional engagement element. It is determined whether or not the state is changed. When the first frictional engagement element is controlled to be in a released state and the second frictional engagement element is controlled to be in a released state, the temperature is equal to or lower than a predetermined temperature; and When it is determined that the gear ratio of the automatic transmission is changed by the second friction engagement element, the first friction engagement element is engaged. Thereby, the state in which the first gear stage is formed can be maintained. Therefore, it can suppress that a gear ratio becomes low. As a result, it is possible to provide a control device for an automatic transmission that can suppress deterioration in acceleration performance.

  According to a second aspect of the present invention, there is provided a control device for an automatic transmission, in addition to the configuration of the first invention, in a state where the first frictional engagement element is controlled to be in an engaged state by the control means. Means are further included for controlling the first frictional engagement element to be in a released state when the degree is greater than or equal to a predetermined value.

  According to the second invention, when it is determined that the temperature is equal to or lower than a predetermined temperature and the gear ratio of the automatic transmission is changed by the second friction engagement element, the first In a state where the friction engagement element is controlled to be in the engaged state, when the accelerator opening is equal to or greater than a predetermined value, the first friction engagement element is brought into the released state. Thereby, when the torque input to the automatic transmission is increased and the influence of the torque transmitted by the second friction engagement element is reduced, the first friction engagement element can be released. . Therefore, it can suppress engaging the 1st friction engagement element unnecessarily.

  According to a third aspect of the present invention, there is provided a control device for an automatic transmission, in addition to the configuration of the first invention, in a state in which the first frictional engagement element is controlled to be engaged by the control means. Means are further included for controlling the first frictional engagement element to be in a released state if it is greater than or equal to the predetermined value.

  According to the third invention, when it is determined that the temperature is equal to or lower than a predetermined temperature and the gear ratio of the automatic transmission is changed by the second friction engagement element, the first In a state where the friction engagement element is controlled to be in the engaged state, when the vehicle speed is equal to or higher than a predetermined value, the first friction engagement element is brought into the released state. As a result, when the vehicle speed increases and the gear is shifted from the first gear to another gear, the first friction engagement element can be released. Therefore, it is possible to suppress an interlock in which a friction engagement element that is engaged when forming the first gear stage and a friction engagement element that is engaged when forming another gear stage are simultaneously engaged. be able to.

  In the control device for an automatic transmission according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the judging means is configured so that the first friction engagement element is in a released state and When the frictional engagement element 2 is controlled to be in the released state, if the input shaft rotational speed and the output shaft rotational speed of the automatic transmission are not synchronized, the second frictional engagement element Means for determining that the gear ratio of the automatic transmission is being changed is included.

  According to the fourth invention, the input shaft of the automatic transmission is controlled when the first friction engagement element is controlled to be in the released state and the second friction engagement element is controlled to be in the released state. If the rotation speed and the output shaft rotation speed are not synchronized, it is determined that the gear ratio of the automatic transmission is changed by the second friction engagement element. For example, if the difference between the value obtained by multiplying the output shaft rotational speed by the gear ratio of the first gear stage and the input shaft rotational speed is greater than a predetermined value, the input shaft rotational speed and the output shaft rotational speed are synchronized. It can be said that it is in a state that does not. Accordingly, it is possible to accurately determine the state in which the gear ratio of the automatic transmission is changed by the second friction engagement element.

  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.

  A vehicle equipped with a control device according to an embodiment of the present invention will be described with reference to FIG. This vehicle is an FR (Front engine Rear drive) vehicle. A vehicle other than FR may be used.

  The vehicle includes an engine 1000, an automatic transmission 2000, a torque converter 2100, a planetary gear unit 3000 that forms part of the automatic transmission 2000, a hydraulic circuit 4000 that forms part of the automatic transmission 2000, a propeller shaft 5000, A differential gear 6000, a rear wheel 7000, and an ECU (Electronic Control Unit) 8000 are included. The control device according to the present embodiment is realized by executing a program recorded in a ROM (Read Only Memory) 8002 of ECU 8000, for example.

  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. The auxiliary power 1004 such as an alternator and an air conditioner is driven by the driving force of the engine 1000. A motor may be used as a power source instead of or in addition to engine 1000.

  Automatic transmission 2000 is connected to engine 1000 via torque converter 2100. Automatic transmission 2000 changes the rotational speed of the crankshaft to a desired rotational speed by forming a desired gear stage.

  The driving force output from automatic transmission 2000 is transmitted to left and right rear wheels 7000 via propeller shaft 5000 and differential gear 6000.

  The ECU 8000 includes a position switch 8006 for the shift lever 8004, an accelerator opening sensor 8010 for the accelerator pedal 8008, a pedaling force sensor 8014 for the brake pedal 8012, a throttle opening sensor 8018 for the electronic throttle valve 8016, and an engine speed sensor 8020. The input shaft rotational speed sensor 8022, the output shaft rotational speed sensor 8024, the oil temperature sensor 8026, and the water temperature sensor 8028 are connected via a harness or the like.

  The position (position) of shift lever 8004 is detected by position switch 8006, and a signal representing 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 stage 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 pedaling force sensor 8014 detects the pedaling force of the brake pedal 8012 (the force with which the driver steps on the brake pedal 8012), and transmits a signal representing the detection result to the ECU 8000.

  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).

  Instead of or in addition to the electronic throttle valve 8016, the amount of air drawn into the engine 1000 can be reduced by changing the lift amount of the intake valve (not shown) or the exhaust valve (not shown) and the opening / closing phase. You may make it adjust.

  Engine rotation speed sensor 8020 detects the rotation speed of the output shaft (crankshaft) of engine 1000 and transmits a signal representing the detection result to ECU 8000. Input shaft rotational speed sensor 8022 detects input shaft rotational speed NI of automatic transmission 2000 (turbine rotational speed NT of torque converter 2100), 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.

  Oil temperature sensor 8026 detects the temperature (oil temperature) of oil (ATF: Automatic Transmission Fluid) used for the operation and lubrication of automatic transmission 2000, and transmits a signal indicating the detection result to ECU 8000.

  Water temperature sensor 8028 detects the temperature (water temperature) of cooling water for engine 1000 and transmits a signal representing the detection result to ECU 8000.

  The ECU 8000 includes a position switch 8006, an accelerator opening sensor 8010, a pedal effort sensor 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 sensor 8026, and a water temperature sensor. Based on a signal sent from 8028 or the like, a map stored in the ROM 8002, and a program, the devices are controlled so that the vehicle is in a desired running state.

  In the present embodiment, ECU 8000 has the forward 1st to 8th gears when the shift lever 8004 is in the D (drive) position and the D (drive) range is selected as the shift range of automatic transmission 2000. Automatic transmission 2000 is controlled so that one of these gears is formed. The automatic transmission 2000 can transmit a driving force to the rear wheel 7000 by forming any one of the first to eighth forward gears. In the D range, it may be possible to form a higher gear than the eighth gear. The gear stage to be formed is determined based on a shift diagram created in advance by experiments or the like using the vehicle speed and the accelerator opening as parameters.

  As shown in FIG. 1, ECU 8000 includes an engine ECU 8100 that controls engine 1000 and an ECT (Electronic Controlled Transmission) _ECU 8200 that controls automatic transmission 2000.

  Engine ECU 8100 and ECT_ECU 8200 are configured to be able to transmit and receive signals to and from each other. In the present embodiment, engine ECU 8100 transmits a signal representing the accelerator opening to ECT_ECU 8200. ECT_ECU 8200 transmits to engine ECU 8100 a signal representing a torque request amount determined as torque to be output by engine 1000.

  The planetary gear unit 3000 will be described with reference to FIG. Planetary gear unit 3000 is connected to a torque converter 2100 having an input shaft 2102 coupled to the crankshaft.

  The planetary gear unit 3000 includes a front planetary 3100, a rear planetary 3200, a C1 clutch 3301, a C2 clutch 3302, a C3 clutch 3303, a C4 clutch 3304, a B1 brake 3311, a B2 brake 3312, and a one-way clutch (F). 3320.

  The front planetary 3100 is a double pinion type planetary gear mechanism. Front planetary 3100 includes a first sun gear (S1) 3102, a pair of first pinion gears (P1) 3104, a carrier (CA) 3106, and a ring gear (R) 3108.

  The first pinion gear (P1) 3104 meshes with the first sun gear (S1) 3102 and the first ring gear (R) 3108. The first carrier (CA) 3106 supports the first pinion gear (P1) 3104 so that it can revolve and rotate.

  First sun gear (S1) 3102 is fixed to gear case 3400 so as not to rotate. First carrier (CA) 3106 is coupled to input shaft 3002 of planetary gear unit 3000.

  The rear planetary 3200 is a Ravigneaux type planetary gear mechanism. The rear planetary 3200 includes a second sun gear (S2) 3202, a second pinion gear (P2) 3204, a rear carrier (RCA) 3206, a rear ring gear (RR) 3208, a third sun gear (S3) 3210, a third Pinion gear (P3) 3212.

  Second pinion gear (P2) 3204 meshes with second sun gear (S2) 3202, rear ring gear (RR) 3208, and third pinion gear (P3) 3212. Third pinion gear (P3) 3212 meshes with third sun gear (S3) 3210 in addition to second pinion gear (P2) 3204.

  The rear carrier (RCA) 3206 supports the second pinion gear (P2) 3204 and the third pinion gear (P3) 3212 so that they can revolve and rotate. Rear carrier (RCA) 3206 is coupled to one-way clutch (F) 3320. The rear carrier (RCA) 3206 becomes non-rotatable when driving the first gear (when traveling using the driving force output from the engine 1000). Rear ring gear (RR) 3208 is coupled to output shaft 3004 of planetary gear unit 3000.

  The one-way clutch (F) 3320 is provided in parallel with the B2 brake 3312. That is, the outer race of the one-way clutch (F) 3320 is fixed to the gear case 3400, and the inner race is connected to the rear carrier (RCA) 3206.

  FIG. 3 shows an operation table showing the relationship between each gear position and the operation state of each clutch and each brake. By operating the brakes and the clutches in the combinations shown in the operation table, a forward 1st to 8th gear and a reverse 1st and 2nd gear are formed.

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

  The hydraulic circuit 4000 includes an oil pump 4004, a primary regulator valve 4006, a manual valve 4100, a solenoid modulator valve 4200, an SL1 linear solenoid (hereinafter referred to as SL (1)) 4210, and an SL2 linear solenoid (hereinafter referred to as “the solenoid valve”). SL2 (described as SL (4)) 4220, SL3 linear solenoid (hereinafter referred to as SL (3)) 4230, SL4 linear solenoid (hereinafter referred to as SL (4)) 4240, and SL5 linear solenoid (hereinafter referred to as SL (3)). , SL (5)) 4250, SLT linear solenoid (hereinafter referred to as SLT) 4300, and B2 control valve 4500.

  Oil pump 4004 is connected to the crankshaft of engine 1000. As the crankshaft rotates, the oil pump 4004 is driven to generate hydraulic pressure. 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. The line pressure is supplied to the manual valve 4100 via the 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 the D position, the line pressure oil passage 4010 and the D range pressure oil passage 4102 are communicated, and hydraulic 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 the R position, 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 D range pressure 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 the N position, both the D range pressure oil passage 4102 and the R range pressure oil passage 4104 are connected to the drain port 4105, and the D range pressure and R of the D range pressure oil passage 4102 are communicated. The R range pressure of the range pressure oil passage 4104 is discharged from the drain port 4105.

  The hydraulic pressure supplied to the D range pressure oil path 4102 is finally supplied to the C1 clutch 3301, the C2 clutch 3302, and the C3 clutch 3303. The hydraulic pressure supplied to the R range pressure oil passage 4104 is finally supplied to the B2 brake 3312.

  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 3301. SL (2) 4220 regulates the hydraulic pressure supplied to C2 clutch 3302. SL (3) 4230 regulates the hydraulic pressure supplied to the C3 clutch 3303. SL (4) 4240 regulates the hydraulic pressure supplied to C4 clutch 3304. SL (5) 4250 regulates the hydraulic pressure supplied to the B1 brake 3311.

  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.

  SL (1) 4210, SL (2) 4220, SL (3) 4230, SL (4) 4240, SL (5) 4250, and SLT 4300 are controlled by a control signal transmitted from ECU 8000.

  The B2 control valve 4500 selectively supplies hydraulic pressure from one of the D range pressure oil passage 4102 and the R range pressure oil passage 4104 to the B2 brake 3312. 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 SLU solenoid valve (not shown) and the biasing force of the spring.

  When 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 3312 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 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 3312.

  The ECU 8000 will be further described with reference to FIG. The functions of ECU 8000 described below may be realized by hardware or may be realized by software.

  Engine ECU 8100 of ECU 8000 includes a torque control unit 8110. The torque control unit 8110 receives the torque request amount output from the ECT_ECU 8200, and the throttle opening of the electronic throttle valve 8016 and the ignition timing by the ignition plug so that the torque corresponding to the torque request amount is output from the engine 1000. To control.

  ECT_ECU 8200 of ECU 8000 includes a torque request unit 8210, a vehicle speed detection unit 8220, a shift control unit 8230, a state determination unit 8240, an oil temperature detection unit 8250, an engagement unit 8260, and a release unit 8270.

  Torque requesting unit 8210 sets a torque request amount that is a torque required for engine 1000 based on the accelerator opening and the like.

  The vehicle speed detector 8220 calculates (detects) the vehicle speed from the output shaft rotational speed NO of the automatic transmission 2000.

  As shown in FIG. 6, the shift control unit 8230 performs an upshift or a downshift according to a shift diagram using the vehicle speed and the accelerator opening as parameters. In the shift diagram, an upshift line and a downshift line are set for each type of shift (combination of the gear stage before the shift and the gear stage after the shift). When the gear shift is performed, the friction engagement elements are normally engaged with the combinations described in the operation table of FIG. 3 described above.

  The state determination unit 8240 indicates that the gear ratio in the state where the B2 brake 3312 is controlled to be in the released state so that the C1 clutch 3301 is in the engaged state when driven at the first forward gear, It is determined whether the state is changed by a friction engagement element other than 3301.

  In other words, it is determined whether or not the friction engagement elements other than the C1 clutch 3301 except for the B2 brake 3312 and the one-way clutch (F) 3320 are in a state of transmitting torque.

  The state determination unit 8240 is controlled so that only the C1 clutch 3301 is engaged and the B2 brake 3312 is controlled to be in the released state, and the input shaft rotational speed NI (turbine rotational speed NT) and the output shaft are controlled. When the rotational speed NO is not synchronized, it is determined that the gear ratio is changed by a friction engagement element other than the C1 clutch 3301.

  For example, when the difference between the value obtained by multiplying the output shaft rotational speed NO by the gear ratio of the first gear is greater than the threshold value, the input shaft rotational speed NI and the output shaft rotational speed NO are Judged out of sync. Note that the method for determining whether or not the gear ratio is changed by a friction engagement element other than the C1 clutch 3301 is not limited to this.

  Oil temperature detection unit 8250 detects the oil temperature based on the signal transmitted from oil temperature sensor 8026.

  Engagement unit 8260 is in a state where the oil temperature is equal to or lower than threshold value THO (0) and the gear ratio is changed by a friction engagement element other than C1 clutch 3301 when driven at the first forward gear. When it is determined that there is, control is performed so that the B2 brake 3312 is engaged.

  The release portion 8270 determines that the oil temperature is equal to or lower than the threshold value THO (0) and the gear ratio is changed by a friction engagement element other than the C1 clutch 3301, and the B2 brake 3312 is engaged. When the accelerator opening is equal to or greater than the threshold value PA (0) or the vehicle speed is equal to or greater than the threshold value V (0), the B2 brake 3312 is controlled to be released. To do.

  With reference to FIG. 7, a control structure of a program executed by ECU 8000 serving as the control device according to the present embodiment will be described. Note that the program described below is repeatedly executed at a predetermined cycle.

  In step (hereinafter, step is abbreviated as S) 100, ECU 8000 determines whether or not it is during driving in a state where the first forward gear is formed. If it is during driving with the forward first gear set (YES in S100), the process proceeds to S110. Otherwise (NO in S100), this process ends.

  In S110, ECU 8000 detects the oil temperature based on the signal transmitted from oil temperature sensor 8026. In S112, ECU 8000 determines whether or not the oil temperature is equal to or lower than threshold value TH0 (0). If the oil temperature is equal to or lower than threshold value TH0 (0) (YES in S112), the process proceeds to S120. If not (NO in S112), the process proceeds to S130.

  In S120, ECU 8000 detects the accelerator opening based on the signal transmitted from accelerator opening sensor 8010. In S122, ECU 8000 determines whether or not the accelerator opening is equal to or greater than threshold value PA (0). If the accelerator opening is equal to or greater than threshold value PA (0) (YES in S122), the process proceeds to S130. If not (NO in S122), the process proceeds to S140.

  In S130, ECU 8000 determines whether or not B2 brake 3312 is engaged. If B2 brake 3312 is in the engaged state (YES in S130), the process proceeds to S180. Otherwise (NO at S130), this process ends.

  In S140, ECU 8000 determines whether or not B2 brake 3312 is in the released state. If B2 brake 3312 is in the released state (YES in S140), the process proceeds to S150. If not (NO in S140), the process proceeds to S170.

  In S150, ECU 8000 detects input shaft rotational speed NI based on the signal transmitted from input shaft rotational speed sensor 8022, and outputs shaft rotational speed NO based on the signal transmitted from output shaft rotational speed sensor 8024. Is detected.

  In S152, ECU 8000 determines whether or not the gear ratio is changed by a friction engagement element other than C1 clutch 3301. If the gear ratio is changed by a friction engagement element other than C1 clutch 3301 (YES in S152), the process proceeds to S160. Otherwise (NO in S152), this process ends. In S160, ECU 8000 places B2 brake 3312 in the engaged state.

  In S170, ECU 8000 detects the vehicle speed based on the signal transmitted from output shaft speed sensor 8024. In S172, ECU 8000 determines whether or not the vehicle speed is equal to or higher than threshold value V (0). If the vehicle speed is equal to or higher than threshold value V (0) (YES in S172), the process proceeds to S180. If not (NO in S172), this process ends. In S180, ECU 8000 places B2 brake 3312 in the released state.

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

  When driving with the forward first gear set (YES in S100), the oil temperature is detected based on the signal transmitted from oil temperature sensor 8026 (S110). If the oil temperature is equal to or lower than threshold value TH0 (0) (YES in S112), the accelerator opening is detected based on the signal transmitted from accelerator opening sensor 8010 (S120). If the accelerator opening is smaller than threshold value PA (0) (NO in S122), it is determined whether or not B2 brake 3312 is in the released state (S140).

  When B2 brake 3312 is in the released state (YES in S140), input shaft rotational speed NI is detected based on the signal transmitted from input shaft rotational speed sensor 8022, and transmitted from output shaft rotational speed sensor 8024. Based on the signal, the output shaft rotational speed NO is detected (S150).

  That is, when the forward first speed gear stage is formed by controlling so that only the C1 clutch 3301 is engaged and the B2 brake 3312 is released, the input shaft rotational speed NI and the output shaft The rotational speed NO is detected (S150).

  At low oil temperature, since the ATF viscosity is high, the C1 clutch 3301 is controlled even when only the C1 clutch 3301 is engaged and the B2 brake 3312 is controlled to be released. Other frictional engagement elements can transmit torque. For example, the B1 brake 3311 that is controlled to be in a released state when the first forward gear stage is formed can transmit torque.

  Accordingly, in a state where the accelerator opening is low, that is, in a state where the torque input from engine 1000 to automatic transmission 2000 is low, a rotating element such as rear carrier (RCA) 3206 of planetary gear unit 3000 has the torque transmitted by B1 brake 3311. Rotated by influence. Therefore, the one-way clutch (F) 3320 cannot be engaged.

  Therefore, the gear ratio of automatic transmission 2000 can be changed to a lower gear ratio than the first forward gear. In such a case, the driving force of the vehicle becomes low. Accordingly, the acceleration performance is deteriorated.

  Therefore, in the present embodiment, since the input shaft rotational speed NI and the output shaft rotational speed NO are not synchronized, the gear ratio is changed by a friction engagement element other than the C1 clutch 3301 ( In S152, YES), the B2 brake 3312 provided in parallel with the one-way clutch (F) 3320 is engaged (S160).

  As a result, the forward first gear can be reliably formed. Therefore, it can suppress that a gear ratio falls and a driving force becomes low. As a result, it is possible to suppress deterioration in acceleration performance.

  Thereafter, the vehicle speed is detected based on the signal transmitted from the output shaft rotational speed sensor 8024 (S172). If vehicle speed is lower than threshold value V (0) (NO in S172), B2 brake 3312 is maintained in the engaged state.

  When driving with the B2 brake 3312 engaged to form the forward first gear (YES in S100), if the oil temperature is higher than threshold value TH0 (0) (NO in S112), C1 It is considered that the possibility that the gear ratio is changed by a friction engagement element other than the clutch 3301 is low. In this case, since B2 brake 3312 is engaged (YES in S130), B2 brake 3312 is released (S180).

  Similarly, if the accelerator opening is equal to or greater than threshold value PA (0) (YES in S122), the input torque of automatic transmission 2000 is high, and therefore the influence of torque transmitted by a friction engagement element other than C1 clutch 3301 is exerted. Becomes relatively small. Therefore, it is considered that the possibility that the gear ratio is changed by a friction engagement element other than the C1 clutch 3301 is low. In this case, since B2 brake 3312 is engaged (YES in S130), B2 brake 3312 is released (S180).

  By the way, when driving in a state where the B2 brake 3312 is engaged and the forward first gear is formed (YES in S100), when the vehicle speed increases, the forward first gear is increased to the forward second gear. A shift is performed.

  At this time, if the B2 brake 3312 is in an engaged state, the friction engagement element to be engaged to form the forward first gear and the forward second gear are formed inside the automatic transmission 2000. An interlock is generated in which the frictional engagement elements to be engaged simultaneously engage.

  In order to suppress the interlock, the oil temperature is lower than threshold value TH0 (0) (YES in S112), the accelerator opening is smaller than threshold value PA (0) (NO in S122), and B2 brake 3312 Is in the engaged state (NO in S140), the vehicle speed is detected (S172). If vehicle speed is equal to or higher than threshold value V (0) (YES in S172), B2 brake 3312 is released (S180). Thereby, an interlock can be suppressed.

  As described above, according to the ECU that is the control device according to the present embodiment, the forward first-speed gear is controlled so that only the C1 clutch is engaged and the B2 brake is released. If the oil temperature is equal to or lower than the threshold value TH0 (0) and the gear ratio is changed by a friction engagement element other than the C1 clutch in the state where the stage is formed, the B2 brake is engaged. Put into state. As a result, the forward first gear can be reliably formed. Therefore, it is possible to suppress a reduction in the driving force due to the gear ratio being lower than the gear ratio of the first forward gear. As a result, it is possible to suppress deterioration in acceleration performance.

  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 of a vehicle. It is a skeleton figure which shows the planetary gear unit of an automatic transmission. It is a figure which shows the operation | movement table | surface of an automatic transmission. It is a figure which shows the hydraulic circuit of an automatic transmission. It is a functional block diagram of ECU. It is a figure which shows a shift map. It is a figure which shows the control structure of the program which ECU performs.

Explanation of symbols

  1000 Engine, 2000 Automatic transmission, 2100 Torque converter, 3000 Planetary gear unit, 3301 C1 clutch, 3302 C2 clutch, 3303 C3 clutch, 3304 C4 clutch, 3311 B1 brake, 3312 B2 brake, 4000 Hydraulic circuit, 8000 ECU, 8002 ROM, 8004 Shift lever, 8006 position switch, 8008 accelerator pedal, 8010 accelerator opening sensor, 8012 brake pedal, 8014 pedal force sensor, 8016 electronic throttle valve, 8018 throttle opening sensor, 8020 engine speed sensor, 8022 input shaft speed sensor, 8024 Output shaft rotational speed sensor, 8026 oil temperature sensor, 8028 water temperature sensor, 8100 Engine ECU, 8110 Torque control unit, 8200 ECT_ECU, 8210 Torque request unit, 8220 Vehicle speed detection unit, 8230 Shift control unit, 8240 State determination unit, 8250 Oil temperature detection unit, 8260 Brake engagement unit, 8270 Brake release unit.

Claims (4)

When the first friction engagement element operated by the pressure of the hydraulic oil is in the released state and the second friction engagement element operated by the pressure of the hydraulic oil is in the released state, and when the first friction engagement element A first gear is formed when the combined element is in the engaged state and the second frictional engagement element is in the released state, and the first frictional engagement element is in the released state; And a control device for an automatic transmission in which a second gear is formed when the second friction engagement element is in an engaged state,
Means for detecting the temperature of the hydraulic oil;
When the first frictional engagement element is controlled to be in a released state and the second frictional engagement element is controlled to be in a released state, the second frictional engagement element causes the automatic A determination means for determining whether or not the gear ratio of the transmission is in a changed state;
When the first friction engagement element is controlled to be in a released state and the second friction engagement element is controlled to be in a released state, the temperature is equal to or lower than a predetermined temperature. When the gear ratio of the automatic transmission is determined to be changed by the second friction engagement element, the first friction engagement element is controlled to be in the engagement state. And a control device for the automatic transmission.   In a state where the first frictional engagement element is controlled to be in an engaged state by the control means, the control device has the first opening when the accelerator opening is equal to or greater than a predetermined value. The control device for an automatic transmission according to claim 1, further comprising means for controlling the friction engagement element to be in a released state.   When the vehicle speed is equal to or higher than a predetermined value in a state where the first friction engagement element is controlled to be in an engaged state by the control means, the control device is configured to perform the first friction engagement. The control device for an automatic transmission according to claim 1, further comprising means for controlling the combined element to be in a released state.   The determination means controls the input of the automatic transmission when the first friction engagement element is controlled to be in a released state and the second friction engagement element is in a released state. And means for determining that the gear ratio of the automatic transmission is changed by the second friction engagement element when the shaft rotational speed and the output shaft rotational speed are not synchronized. Item 4. The control device for an automatic transmission according to any one of Items 1 to 3.

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