JP2011208695A - Control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an automatic transmission, for compatibly improving the startability of a vehicle and improving the driveability thereof when finishing neutral control.SOLUTION: A T-ECU determines a reset mode (Step S4) in accordance with a change speed relative to the footing amount of a brake pedal and the footing or not of an accelerator pedal when determining that resetting conditions are established during executing neutral control (YES in Step S3). The T-ECU starts counting using a timer (Step S6) when determining that a turbine rotating speed is not higher than a reference turbine rotating speed corresponding to the reset mode (YES in Step S5), and releases a B1 brake (Step S16) when determining that the counting using the timer reaches a waiting time corresponding to the reset mode (YES in Step S6).

Description

  The present invention relates to an automatic transmission control device, and more particularly, to an automatic transmission control device that performs neutral control.

  In general, in a control device for an automatic transmission, when a vehicle stops in a forward range, driving force generated by engine idling rotation is transmitted as creep force to driving wheels via a torque converter and a transmission mechanism. Creep phenomenon occurs. In order to maintain the stop of the vehicle, the driver needs to operate the brake to suppress the creep force, and there is a problem that the fuel consumption of the engine is reduced by the amount of the creep force consumed by the brake. Therefore, when the brake pedal is depressed in the forward range state and the vehicle is stopped in a state where the accelerator pedal is not depressed, the first engagement element that is engaged at the start is moved from the engagement state. Neutral control is performed to shift the automatic transmission to the neutral state by shifting to the half-engaged state.

  In addition, when such neutral control is executed, the driving force transmitted from the engine to the drive wheels is reduced, so that the vehicle may move backward when the driver finishes stepping on the brake pedal when starting off the slope. Will occur. Therefore, such a control device is in a hill hold mode in which the second engagement element that is in the released state at the start is engaged so that the vehicle does not move backward even when the depression of the brake pedal is completed at the start from the uphill road. It is supposed to migrate.

  Conventionally, in this type of automatic transmission control device, when the first engagement element is shifted from the semi-engaged state to the engaged state in the return mode in which the neutral control is terminated and the automatic transmission is shifted to the driving state. A device that prevents fluctuations in output torque transmitted to drive wheels is known (see, for example, Patent Document 1).

  The conventional automatic transmission control device described in Patent Document 1 starts engaging the first engagement element when the neutral control execution termination condition is satisfied and the hill hold mode is shifted to the return mode. When the engagement of the first engagement element is completed, the second engagement element is released.

  As a result, since the engagement of the second engagement element continues while the first engagement element transitions from the semi-engagement state to the engagement state, the engagement state of the first engagement element The variation of the output torque due to the change is suppressed.

Japanese Patent Laid-Open No. 10-19121

  However, in the conventional automatic transmission control device described in Patent Document 1 as described above, the fluctuation of the output torque generated when the first engagement element is engaged is improved. However, no consideration was given to the release of the second engagement element.

  Therefore, there is a possibility that the start of the second engagement element is not completed even though a quick vehicle start request is generated, and the start is delayed or the start request is low even when the start request is low. Since the second engagement element is released in the same manner as when the engine speed is high, the output torque fluctuates due to the release of the second engagement element, and the vehicle is shocked. Therefore, there is a problem that it is impossible to achieve both improvement in vehicle startability and improvement in drivability.

  The present invention has been made to solve such a problem, and an automatic transmission control device capable of improving both vehicle startability and drivability at the end of neutral control. The purpose is to provide.

  In order to achieve the above object, an automatic transmission control apparatus according to the present invention includes: (1) a speed change mechanism that outputs power input from a power source at a speed ratio corresponding to one of a plurality of speed stages. The automatic transmission control device includes a first engagement element that is engaged when the vehicle is started and a second engagement element that is released, and the start mechanism detects a start request for the vehicle. Executing a hill hold mode for decreasing the engagement pressure of the first engagement element and increasing the engagement pressure of the second engagement element while the vehicle is stopped in the forward range, Neutral control means for executing a return mode for engaging the first engagement element and releasing the second engagement element when the vehicle starts, wherein the neutral control means comprises the start request detection means. By Setting the release timing of the second engagement element in the return mode according to the degree of the issued starting demand, characterized in that.

  With this configuration, the release timing of the second engagement element can be changed according to the degree of the start request to the vehicle of the driver, so priority is given to quickly ending the return mode according to the degree of the start request. Or giving priority to the prevention of vibrations generated in the vehicle. Therefore, it is possible to achieve both improvement in vehicle startability and improvement in drivability.

  In the automatic transmission control apparatus according to (1), (2) a reference point for the input shaft rotation speed of the transmission mechanism is set according to the degree of the start request detected by the start request detecting means. Reference point setting means is provided, wherein the neutral control means sets the release timing as a time when a predetermined time elapses from the time when the input shaft rotational speed decreases to the reference point set by the reference point setting means. To do.

  With this configuration, the release timing can be adjusted by changing the reference point for the input shaft speed according to the degree of the driver's start request. Therefore, it is possible to improve the accuracy with respect to the release timing of the second engagement element, and to realize both improvement in vehicle startability and improvement in drivability.

  In the automatic transmission control apparatus according to (1), (3) a shift progress degree calculating means for calculating a shift progress degree in the return mode based on an input shaft rotational speed of the speed change mechanism; Reference point setting means for setting a reference point for the shift progress degree according to the degree of the start request detected by the request detection means, wherein the neutral control means calculates the shift progress calculated by the shift progress degree calculating means. The release timing is a time when a predetermined time has elapsed from a time when the degree reaches the reference point set by the reference point setting means.

  With this configuration, it is possible to adjust the release timing by changing the reference point for the shift progress according to the degree of the driver's start request. Therefore, it is possible to improve the accuracy with respect to the release timing of the second engagement element, and to realize both improvement in vehicle startability and improvement in drivability.

  In the automatic transmission control apparatus according to (2) or (3), (4) the start request detecting means detects a degree of the start request based on a brake pedal force and an accelerator pedal force. And

  With this configuration, since the driver changes the depression of the brake pedal and the accelerator pedal in response to the start request, it is possible to accurately calculate the degree of the start request to the vehicle by the driver based on the brake depression force and the accelerator depression force. Become.

  In the automatic transmission control device according to (4), (5) the reference point setting means sets the reference point so that the release timing is earlier as the decrease in the brake pedal force is faster. Features.

  With this configuration, when the driver promptly starts the vehicle and the brake pedal force decreases rapidly, the return mode is shortened by setting the reference point so that the release timing of the second engagement element is advanced. It becomes possible. In addition, when quick start of the vehicle is not required, drivability can be improved by delaying the release timing of the second engagement element.

  In the automatic transmission control apparatus according to the above (4) or (5), (6) the reference point setting means is configured so that the release timing is earlier as the increase in the accelerator pedal force is detected earlier. A reference point is set.

  With this configuration, when the driver requires a quick start of the vehicle and the accelerator pedal is depressed quickly, the return is set by setting the reference point so that the release timing of the second engagement element is advanced. The mode can be shortened. In addition, when quick start of the vehicle is not required, drivability can be improved by delaying the release timing of the second engagement element.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of the automatic transmission which can make the improvement of vehicle startability and the improvement of drivability compatible at the time of completion | finish of neutral control can be provided.

1 is a schematic configuration diagram schematically showing a vehicle equipped with an automatic transmission control device according to an embodiment of the present invention. 1 is a skeleton diagram showing a configuration of a control device for an automatic transmission according to an embodiment of the present invention. It is an operation | movement table | surface of the automatic transmission which concerns on embodiment of this invention. 1 is a circuit diagram showing a schematic configuration of a hydraulic control circuit according to an embodiment of the present invention. It is a timing chart which shows the neutral control which concerns on embodiment of this invention. It is a flowchart which shows the neutral control which concerns on embodiment of this invention. It is a graph which shows an example of the instruction | indication oil_pressure | hydraulic which concerns on embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram schematically showing a vehicle equipped with a control device for an automatic transmission according to an embodiment of the present invention. FIG. 2 is a skeleton diagram showing the configuration of the control device for the automatic transmission according to the embodiment of the present invention.

  In the present embodiment, a case will be described in which the control device for an automatic transmission according to the present invention is applied to an FF (Front engine Front drive) vehicle.

  As shown in FIG. 1, the vehicle 1 includes an engine 2, a torque converter 3, a transmission mechanism 4 having a forward clutch, a hydraulic control circuit 9 for controlling the torque converter 3 and the transmission mechanism 4 with hydraulic pressure, An E-ECU (Electronic Control Unit) 11 for controlling the engine 2 as a source and a T-ECU 12 for controlling the hydraulic control circuit 9 are configured.

  The engine 2 is constituted by 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. A rotating electrical machine or the like may be used instead of the engine 2.

  The torque converter 3 increases the torque from the engine 2 to the speed change mechanism 4 to transmit the power of the engine 2 and, as will be described later, a pump impeller (hereinafter simply referred to as “impeller”) connected to the output shaft of the engine 2. An impeller 43), a turbine runner (hereinafter simply referred to as a turbine 44) connected to the input shaft of the speed change mechanism 4, and a stator 46 that is prevented from rotating in one direction by a one-way clutch 45. The impeller 43 and the turbine 44 transmit power via a fluid.

  Furthermore, the torque converter 3 is a lock-up clutch 47 (in order to increase power transmission efficiency from the engine 2 to the transmission mechanism 4 by mechanically connecting the impeller 43 and the turbine 44 when the vehicle 1 is traveling at high speed. 2).

  The torque converter 3 and the speed change mechanism 4 constitute an automatic transmission 5. The automatic transmission 5 shifts the rotation speed of a crankshaft (not shown) to a desired rotation speed by forming a desired shift speed. The power output from the output gear 70 of the speed change mechanism 4 is transmitted to left and right front wheels (not shown) via a differential gear and a drive shaft (not shown). The transmission mechanism 4 will be described in detail later.

  The hydraulic control circuit 9 has linear solenoid valves SL1 to SL4. The hydraulic control circuit 9 has an oil temperature sensor 33 for measuring the oil temperature of the hydraulic oil.

  The E-ECU 11 has a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an input / output interface (not shown). The E-ECU 11 controls the rotational speed of the engine 2 by the CPU based on signals input from an accelerator sensor and a throttle sensor, which will be described later, a map stored in the ROM, and the like.

  The T-ECU 12 has a CPU, a RAM, a ROM, and an input / output interface (not shown). The ROM of the T-ECU 12 stores a map in which the vehicle speed and throttle opening are associated with the gear position of the transmission mechanism 4. Therefore, the T-ECU 12 determines the gear position of the transmission mechanism 4 by the CPU based on a signal input from a vehicle speed sensor 25 and a throttle sensor 24 described later and a map stored in the ROM.

  The T-ECU 12 changes the operating state of the linear solenoid valves SL1 to SL4, and selectively engages or releases the friction element of the speed change mechanism 4 with the operating hydraulic pressure using the line pressure as the original pressure. The ratio of the rotational speed between the input shaft and the output shaft of the speed change mechanism 4 is changed by a combination of engagement and release of these friction elements, so that a gear stage is configured.

  The vehicle 1 further includes an engine rotation speed sensor 21 for measuring the rotation speed Ne of the engine 2, an intake air amount sensor 22 for measuring the intake air amount of the engine 2, and the amount of air sucked into the engine 2. An intake air temperature sensor 23 for measuring the temperature, a throttle sensor 24 for detecting the opening of the throttle valve 31, a vehicle speed sensor 25, a cooling water temperature sensor 26 for measuring the cooling water temperature of the engine 2, A brake sensor 27, an operation position sensor 29 for detecting the operation position of the shift lever 28, and a turbine rotation speed sensor 30 for measuring the rotation speed Nt of the turbine 44 of the torque converter 3 are provided.

  The engine speed sensor 21 measures the speed of the engine 2 based on the rotation of the crankshaft.

  The throttle sensor 24 is constituted by, for example, a hall element that can obtain an output voltage corresponding to the throttle opening of the throttle valve 31. The throttle sensor 24 outputs this output voltage to the E-ECU 11 and the T-ECU 12 as a signal representing the throttle opening of the throttle valve 31.

  The vehicle speed sensor 25 outputs a signal representing the output shaft rotational speed of the transmission mechanism 4 to the E-ECU 11 and the T-ECU 12, and the E-ECU 11 and the T-ECU 12 calculate the vehicle speed based on this signal. It is supposed to be.

  The cooling water temperature sensor 26 is composed of, for example, a thermistor whose resistance value changes according to the water temperature, and outputs a signal based on the resistance value that changes according to the cooling water temperature of the engine 2 to the E-ECU 11 and the T-ECU 12. It is like that.

  The brake sensor 27 transmits a signal corresponding to the amount of depression of the driver with respect to the brake pedal 36 provided in the vehicle 1 to the E-ECU 11 and the T-ECU 12. The T-ECU 12 determines that the brake OFF signal has been input when a signal indicating that the depression amount with respect to the brake pedal 36 is smaller than a predetermined value is acquired from the brake sensor 27. Therefore, the T-ECU 12 constitutes means for detecting the brake pedal effort.

  The vehicle 1 replaces the brake sensor 27 with a stop lamp switch that outputs a brake ON signal when the driver depresses the brake pedal 36 and outputs a brake OFF signal when the brake pedal 36 is not depressed. You may make it provide.

  The operation position sensor 29 detects the position of the shift lever 28 and transmits a signal representing the detection result to the T-ECU 12. The T-ECU 12 forms an optimum gear position of the transmission mechanism 4 from a range corresponding to the position of the shift lever 28. Further, the operation position sensor 29 may be configured to detect that the shift lever 28 is located at a manual position where the driver can select an arbitrary gear position according to the operation of the driver.

  The accelerator opening sensor 32 is composed of, for example, an electronic position sensor using a hall element. When the accelerator pedal 34 mounted on the vehicle 1 is operated by the driver, the accelerator position indicated by the accelerator pedal 34 is indicated. A signal indicating the opening is output to the E-ECU 11. Further, the T-ECU 12 receives a signal representing the accelerator opening degree via the E-ECU 11. Therefore, the T-ECU 12 constitutes a means for detecting the accelerator pedal force.

  As shown in FIG. 2, the torque converter 3 is rotated in one direction by an impeller 43 connected to the output shaft 41 of the engine 2, a turbine 44 connected to the input shaft 48 of the transmission mechanism 4, and the one-way clutch 45. And a stator 46 that is blocked. The impeller 43 and the turbine 44 transmit power via a fluid.

  The input shaft 48 of the transmission mechanism 4 is connected to the turbine 44 of the torque converter 3. Therefore, the input shaft 48 of the speed change mechanism 4 also functions as an output shaft of the torque converter 3. The transmission mechanism 4 includes a first set 50 of planetary gear mechanisms, a second set 60 of planetary gear mechanisms, an output gear 70, a B1 brake 72, a B2 brake 73 and a B3 brake 74 fixed to a gear case 71, and C1. The clutch 75, the C2 clutch 76, and the one-way clutch F77 are included.

  The first set 50 includes a single pinion type planetary gear mechanism. The first set 50 includes a sun gear 51, a pinion gear 52, a ring gear 53, and a carrier 54.

  The sun gear 51 is connected to the turbine 44 of the torque converter 3 via the input shaft 48. The pinion gear 52 is rotatably supported by the carrier 54. The pinion gear 52 is engaged with the sun gear 51 and the ring gear 53.

  The ring gear 53 can be selectively fixed to the gear case 71 by a B3 brake 74. The carrier 54 can be selectively fixed to the gear case 71 by the B1 brake 72.

  The second set 60 is constituted by a Ravigneaux type planetary gear mechanism. The second set 60 includes a sun gear 61, a short pinion gear 62, carriers 63 and 65, a long pinion gear 64, a sun gear 66, and a ring gear 67.

  The sun gear 61 is connected to the carrier 54. The short pinion gear 62 is rotatably supported by the carrier 63. The short pinion gear 62 is engaged with the sun gear 61 and the long pinion gear 64. The carrier 63 is connected to the output gear 70.

  The long pinion gear 64 is rotatably supported by the carrier 65. The long pinion gear 64 is engaged with the short pinion gear 62, the sun gear 66 and the ring gear 67. The carrier 65 is connected to the output gear 70.

  The sun gear 66 can be selectively connected to the input shaft 48 via the C1 clutch 75. The ring gear 67 can be selectively fixed to the gear case 71 by the B2 brake 73 and can be selectively connected to the input shaft 48 by the C2 clutch 76. The ring gear 67 is connected to the one-way clutch F77, so that the gear position is one and cannot be rotated during driving.

  FIG. 3 is an operation table of the automatic transmission 5 according to the embodiment of the present invention. “◯” represents engagement. “X” represents release. “◎” represents engagement only during engine braking. “Δ” represents engagement only during driving. By operating the brakes and the clutches by exciting and de-energizing linear solenoid valves SL1 to SL4 provided in the hydraulic control circuit 9 (see FIG. 1) and a transmission solenoid (not shown) in the combinations shown in the operation table. A first to sixth forward shift stage and a reverse shift stage are formed.

  Here, since the one-way clutch F77 is provided in parallel with the B2 brake 73, as indicated by “◎” in the operation table, the drive state from the engine side when the first speed (1st) of the shift stage is formed. It is not necessary to engage the B2 brake 73 (during acceleration). In the present embodiment, the one-way clutch F77 is configured to prevent the ring gear 67 from rotating during driving when the gear stage is at the first speed. On the other hand, when the engine brake is applied, the one-way clutch F77 does not prevent the ring gear 67 from rotating.

  As shown in the operation table, the C1 clutch 75 is engaged at the first (1st) shift stage formed when the vehicle 1 starts. Accordingly, the C1 clutch 75 functions as a forward clutch and constitutes a first engagement element that is engaged when starting. Further, the B1 brake 72 is released at the first gear (1st). Accordingly, the B1 brake 72 constitutes a second engagement element that is released when the vehicle starts.

  The shift lever 28 (see FIG. 1) has an L position corresponding to the low range, a 2-3 position corresponding to the second to third ranges, a drive range (hereinafter simply referred to as a D range) from the rear to the front of the vehicle 1. ), N position corresponding to the neutral range, R position corresponding to the reverse range, and P position corresponding to the parking range. The forward range according to the present invention refers to at least the forward range, excluding the neutral range, reverse range, and parking range, and in the present embodiment refers to the D range.

  When the shift lever 28 (see FIG. 1) is located in the D range, the gear stage is configured to form any one of the first to sixth gears. As described above, the T-ECU 12 Of these gears, the gear is selected based on the vehicle speed and the throttle opening.

  The shift lever 28 (see FIG. 1) is further provided with an M position representing a manual position for shifting the shift stage of the automatic transmission 5 (see FIG. 1) in the manual shift mode, and a plus position for instructing an upshift ( (+ Position) and a minus position (-position) for instructing a downshift may be taken. In this case, the M position is positioned beside the D position. When the shift lever 28 (see FIG. 1) is moved sideways from the D position, the shift lever 28 is held at the M position by a spring (not shown).

  FIG. 4 is a circuit diagram showing a schematic configuration of the hydraulic control circuit 9 according to the embodiment of the present invention. The hydraulic fluid pumped from the oil pump 38 is regulated by the relief-type first pressure regulating valve 40 to become the first line pressure PL1. The oil pump 38 is constituted by, for example, a mechanical pump that is rotationally driven by the engine 2.

  The hydraulic oil having the first line pressure PL1 is supplied to the manual valve 39 that is interlocked with the shift lever 28 (see FIG. 1). When the shift lever 28 is located at a position corresponding to the forward range, hydraulic oil having a forward position pressure PD equal to the first line pressure PL1 is supplied from the manual valve 39 to the linear solenoid valves SL1 to SL4. It has become.

  The linear solenoid valves SL1 to SL4 are disposed to correspond to the C1 clutch 75, the C2 clutch 76, the B1 brake 72, and the B3 brake 74, respectively. The T-ECU 12 controls the hydraulic solenoids PC1, PC2, PB1, and PB3 by controlling these linear solenoid valves SL1 to SL4 with a solenoid current, and controls the C1 clutch 75, the C2 clutch 76, the B1 brake 72, and the B3 brake 74. Switch between engagement and release, or adjust engagement pressure.

  Hereinafter, a characteristic configuration of the T-ECU 12 constituting the control device for the automatic transmission 5 according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  The T-ECU 12 determines whether or not the neutral control operation condition is satisfied while the vehicle 1 is stopped. Specifically, the T-ECU 12 determines that the position of the shift lever 28 detected by the operation position sensor 29 is the D position, the vehicle speed detected by the vehicle speed sensor 25 is 0, and the brake pedal 36 is depressed. When the brake sensor 27 detects that the accelerator pedal 34 is not depressed and the accelerator opening sensor 32 detects that the accelerator pedal 34 is not depressed, the neutral control execution condition is satisfied. It is judged that it is established. In addition to these conditions, the T-ECU 12 indicates that the cooling water temperature of the engine 2 detected by the cooling water temperature sensor 26 is equal to or higher than a predetermined value, or the oil temperature of the hydraulic oil detected by the oil temperature sensor 33 is Conditions such as being greater than or equal to a predetermined value may be added.

  When the neutral control execution condition is satisfied, the T-ECU 12 shifts the C1 clutch 75 from the engaged state to the half-engaged state, and prevents the vehicle 1 from moving backward on the uphill road. Execute the hill hold mode to engage. That is, the T-ECU 12 constitutes a neutral control means according to the present invention. In the present embodiment, the half-engaged state of the C1 clutch 75 means that the C1 clutch 75 is in a slip state between the engaged state and the released state.

  Further, the T-ECU 12 determines whether or not a return condition for starting a return mode for shifting the speed change mechanism 4 from the neutral state to the drive state is satisfied during execution of the neutral control. Specifically, the T-ECU 12 determines that the return condition is satisfied when the signal acquired from the brake sensor 27 is switched from the brake ON signal to the brake OFF signal when the driver depresses the brake pedal 36. It comes to judge. When the vehicle 1 includes a stop lamp switch, the T-ECU 12 determines that the return condition is satisfied when the signal input from the stop lamp switch is switched from the ON signal to the OFF signal. It has become. In addition, the T-ECU 12 predicts whether or not the brake is released according to the pressure value in the master cylinder that converts the brake pedal force to hydraulic pressure instead of the stop lamp switch, and the return condition is established based on this prediction. You may make it judge. Further, the T-ECU 12 determines that the return condition is satisfied even when a predetermined time has elapsed from the start of execution of the neutral control.

  Further, when the T-ECU 12 determines that the return condition is satisfied, the T-ECU 12 determines which of the normal brake OFF return, the brake slow release return, the brake ON return, and the accelerator ON return. ing.

  Here, the slow release release of the brake means that the change rate of the depression amount of the brake pedal 36 when the signal output from the brake sensor 27 switches from the brake ON signal to the brake OFF signal is equal to or less than a predetermined value. Means. It should be noted that the T-ECU 12 performs braking based on a signal that represents the change rate of the brake pedal force, such as a signal that represents the pressure change rate in the master cylinder that converts the brake pedal force to hydraulic pressure, instead of the signal input from the brake sensor 27. It may be determined whether or not it is released slowly.

  The brake-on return means that the return condition is satisfied when a predetermined time has elapsed since the start of the neutral control.

  The accelerator ON return means that the accelerator opening sensor 32 detects that the accelerator pedal 34 is depressed immediately after the signal output from the brake sensor 27 is switched from the brake ON signal to the brake OFF signal. To do. Here, “immediately after switching to the brake OFF signal” means a time sufficiently shorter than the duration of the return mode.

  In addition, normal brake OFF return means a return other than brake release slowly, brake ON return, and accelerator ON return.

  Therefore, the T-ECU 12 constitutes a start request detecting means for detecting the degree of the start request based on the brake pedal force and the accelerator pedal force, and the normal brake OFF return, the brake slowly released return, and the brake ON return according to the start request degree. Of the accelerator ON return, it is determined which return is in effect.

  When the T-ECU 12 determines that the return condition is satisfied, the T-ECU 12 starts the return mode and shifts the C1 clutch 75 from the semi-engaged state to the engaged state. Thereby, the turbine rotational speed Nt detected by the turbine rotational speed sensor 30 starts to decrease.

Further, the T-ECU 12 determines whether or not the turbine rotational speed Nt is equal to or lower than a predetermined reference turbine rotational speed Ntc _i (1 ≦ i ≦ 4).

Here, the reference turbine speeds Ntc ₁ , Ntc ₂ , Ntc ₃ and Ntc ₄ represent the reference turbine speeds for the normal brake OFF return, brake release slowly return, brake ON return and accelerator ON return, respectively. reference turbine speed Ntc _i of is stored in the ROM in advance T-ECU 12.

Moreover, T-ECU 12, when the turbine speed Nt is determined to have become equal to or less than the reference turbine speed Ntc _i is adapted to start time measurement by the timer. When the predetermined waiting time t (s) _i (1 ≦ i ≦ 4) elapses after the T-ECU 12 determines that the turbine rotational speed Nt has become equal to or less than the reference turbine rotational speed Ntc _i , the B1 brake 72 is released, and the first speed is formed in the speed change mechanism 4. Therefore, the T-ECU 12 constitutes a neutral control means for setting the release timing of the second engagement element in the return mode according to the degree of the start request.

Here, the predetermined waiting time t (s) _i is set as follows, and is stored in advance in the ROM of the T-ECU 12.

  First, during execution of the hill hold mode, the C1 clutch 75 is half-engaged and the B1 brake 72 is engaged, and the transmission mechanism 4 has a second gear. When the return condition for terminating the neutral control is established, the T-ECU 12 increases the engagement pressure of the C1 clutch 75 and shifts the B1 brake 72 from the engaged state to the half-engaged state.

  When the engagement pressure of the C1 clutch 75 starts to increase, the turbine rotation speed Nt starts to decrease. At this time, since the B1 brake 72 is engaged, the output torque transmitted to the output gear 70 increases slightly, but is substantially constant. When the turbine speed Nt drops to 0 at the end of the inertia, the output torque of the engine 2 is consumed in the converter 3, so the output torque transmitted to the output gear 70 drops. On the other hand, when the B1 brake 72 is released when the neutral control is finished, the gear stage formed in the transmission mechanism 4 is shifted from the second speed to the first speed. Due to this downshift, the output torque transmitted from the engine 2 to the output gear 70 increases.

  Therefore, by releasing the B1 brake 72 at the end of the inertia, the drop in the output torque due to the end of the inertia and the increase in the output torque due to the downshift cancel each other, and the fluctuation of the output torque transmitted to the output gear 70 is suppressed. Thus, vibrations can be prevented from occurring in the vehicle 1.

  Here, the timing at which the output torque transmitted to the output gear 70 drops due to the end of inertia changes in accordance with the decreasing speed of the turbine rotational speed Nt.

The decreasing speed of the turbine rotation speed Nt changes in accordance with each return state of normal brake OFF return, brake slow release return, brake ON return, and accelerator ON return. Therefore, the predetermined waiting time t (s) _i is obtained in advance by experimental measurement in accordance with each return state of normal brake OFF return, brake slow release return, brake ON return, and accelerator ON return.

The reference turbine speed Ntc _i is set as follows.

First, when the accelerator is turned on, a quick acceleration request for the vehicle 1 is generated by the driver. Therefore, it is necessary to accelerate the release of the B1 brake 72 as compared with the normal brake OFF return. Therefore, Ntc ₄ > Ntc ₁ is satisfied.

Further, in the brake slow release return, the driver's demand for acceleration on the vehicle 1 is lower than in the normal brake OFF return. Similarly, in the brake-on return, the driver's demand for acceleration on the vehicle 1 is low to the same extent or more than the brake release slowly. Therefore, at the time of such return, even if the release of the B1 brake 72 is delayed later than usual, the start of the vehicle 1 is not affected. Therefore, Ntc ₁ > Ntc ₂ ≧ Ntc ₃ is satisfied.

From the above, the reference turbine speed Ntc _i is set to satisfy Ntc ₄ > Ntc ₁ > Ntc ₂ ≧ Ntc ₃ . Therefore, the T-ECU 12 constitutes a reference point setting unit according to the present invention, and the reference turbine speed constitutes a reference point according to the present invention.

Then, when the waiting time t (s) _i has elapsed, the T-ECU 12 drains the hydraulic oil for the B1 brake 72 and releases the B1 brake 72. Here, the time when the waiting time t (s) _i elapses and the drain of the hydraulic oil to the B1 brake 72 is started means the release timing according to the present invention.

  Next, neutral control in the T-ECU 12 will be described with reference to a timing chart shown in FIG.

  The T-ECU 12 determines that the return condition for ending the neutral control is satisfied at the time T1, and increases the hydraulic pressure of the hydraulic oil supplied to the C1 clutch 75 to the shelf pressure (see the solid line 83). As a result, the turbine rotational speed Nt starts to decrease (see the solid line 82). At this time, the T-ECU 12 reduces the hydraulic pressure of the hydraulic oil supplied to the B1 brake 72 within a range in which the engaged state can be maintained (see the solid line 84), so that the B1 brake 72 is released at the release timing. To be released quickly.

Moreover, T-ECU 12 is above normal braking OFF return, brake slowly release returning the brake ON restoration, according to any one of the accelerator ON return, setting a reference turbine speed Ntc _i.

Then, T-ECU 12 at time T2, if the turbine speed Nt is determined to lower than the reference turbine speed Ntc _i, starts counting by the timer.

The T-ECU 12 drains the hydraulic oil supplied to the B1 brake 72 when the waiting time t (s) _i has elapsed from the start of timing. Thereby, at time T3, the output torque falls due to the end of the inertia phase, and the torque increases due to the downshift of the gear stage formed in the transmission mechanism 4 from the second speed to the first speed (see the broken line 86). Cancel each other, the torque output to the output gear 70 is kept constant, and the vehicle 1 can be prevented from vibrating (see the solid line 85).

  A broken line 87 represents, for comparison, fluctuations in output torque when the B1 brake 72 is released during execution of the return mode. As the engagement pressure of the C1 clutch 75 increases, the output torque transmitted to the output gear 70 increases. When the inertia phase ends, the output torque drops and a shock occurs in the vehicle 1.

  Next, the neutral control operation will be described with reference to FIG. The process described below is realized by a program stored in advance in the ROM of the T-ECU 12, and is executed by the CPU of the T-ECU 12 at predetermined time intervals.

  First, the T-ECU 12 determines whether or not a neutral control start condition is satisfied (step S1). As described above, the T-ECU 12 determines that the shift lever 28 is in the D position, the vehicle speed is 0, the brake pedal 36 is depressed, and the accelerator pedal 34 is not depressed. If the condition is also established, it is determined that the neutral control execution condition is established.

  If the T-ECU 12 determines that the neutral control execution condition is satisfied (YES in step S1), the process proceeds to step S2. On the other hand, if it is determined that the neutral control execution condition is not satisfied (NO in step S1), this step is repeated.

  Next, the T-ECU 12 performs neutral control (step S2). In the neutral control, the T-ECU 12 shifts the C1 clutch 75 from the engaged state to the half-engaged state and shifts to the hill hold mode in which the B1 brake 72 is engaged.

  Next, the T-ECU 12 determines whether or not a return condition for starting the transition from the hill hold mode to the return mode is satisfied in order to end the neutral control (step S3).

  The T-ECU 12 returns when the signal acquired from the brake sensor 27 is switched from the brake ON signal to the brake OFF signal, or when the duration from the start of the neutral control exceeds a predetermined time, for example, several minutes. It is determined that the condition is met.

  If the T-ECU 12 determines that the return condition is satisfied (YES in step S3), the process proceeds to step S4. On the other hand, if it is determined that the return condition is not satisfied (NO in step S3), this step is repeated.

  When the T-ECU 12 determines that the return condition is satisfied, the T-ECU 12 determines the amount of depression of the brake pedal 36 based on the amount of change in the amount of depression during a minute time of the signal input from the brake sensor 27 at that time. Calculate the rate of change. Further, based on a signal input from the accelerator pedal 34, it is determined whether or not the accelerator pedal 34 is depressed.

  Next, the T-ECU 12 determines whether or not the normal brake is off (step S4). Specifically, the T-ECU 12 determines that the normal brake is OFF when the change speed of the depression amount of the brake pedal 36 exceeds a predetermined value and the accelerator pedal 34 is not depressed. .

  If the T-ECU 12 determines that the normal brake OFF return has occurred (YES in step S4), the process proceeds to step S5.

In step S5, T-ECU 12 is the turbine speed Nt is determined whether a reference turbine speed Ntc ₁ below. When the turbine speed Nt exceeds the reference turbine speed Ntc ₁ (NO in step S5), the T-ECU 12 repeats step S5. On the other hand, when the turbine rotational speed Nt becomes equal to or less than the reference turbine rotational speed Ntc ₁ (YES in step S5), the process proceeds to step S6, and time measurement by a timer is started.

In step S6, the T-ECU 12 determines whether or not the time measured by the timer has reached the waiting time t (s) ₁ . If the T-ECU 12 determines that the waiting time t (s) ₁ has not been reached (NO in step S6), it repeats step S6. On the other hand, if it is determined that the time measured by the timer has reached the waiting time t (s) ₁ (YES in step S6), the process proceeds to step S16.

  On the other hand, when the T-ECU 12 determines that the normal brake OFF return is not made (NO in step S4), the process proceeds to step S7.

  In step S7, the T-ECU 12 determines whether or not the brake is released slowly. Specifically, the T-ECU 12 determines that the brake is released slowly when the change speed of the depression amount of the brake pedal 36 is equal to or less than a predetermined value and the accelerator pedal 34 is not depressed.

  If the T-ECU 12 determines that the brake is released slowly (YES in step S7), the process proceeds to step S8. On the other hand, if it is determined that the brake has not been released slowly (NO in step S7), the process proceeds to step S10.

In step S8, T-ECU 12 is the turbine speed Nt is determined whether a reference turbine speed Ntc ₂ below. When the turbine speed Nt exceeds the reference turbine speed Ntc ₂ (NO in step S8), the T-ECU 12 repeats step S8. On the other hand, when the turbine rotational speed Nt becomes equal to or lower than the reference turbine rotational speed Ntc ₂ (YES in step S8), the process proceeds to step S9, and time measurement by a timer is started.

In step S9, the T-ECU 12 determines whether or not the time measured by the timer has reached the waiting time t (s) ₂ . If the T-ECU 12 determines that the waiting time t (s) ₂ has not been reached (NO in step S9), it repeats step S9. On the other hand, if it is determined that the time measured by the timer has reached the waiting time t (s) ₂ (YES in step S9), the process proceeds to step S16.

  On the other hand, the T-ECU 12 determines in step S7 that the brake is slowly released and does not return, and if the process proceeds to step S10, the T-ECU 12 determines whether it is a brake ON return. Specifically, when the brake ON signal is input from the brake sensor 27, the T-ECU 12 determines that the brake is on.

  If the T-ECU 12 determines that the brake has been turned on (YES in step S10), the process proceeds to step S11. On the other hand, when it is determined that the brake is not returned (NO in step S10), the process proceeds to step S13.

In step S11, T-ECU 12 is the turbine speed Nt is determined whether a reference turbine speed Ntc ₃ below. When the turbine speed Nt exceeds the reference turbine speed Ntc ₃ (NO in step S11), the T-ECU 12 repeats step S11. On the other hand, when the turbine rotational speed Nt becomes equal to or less than the reference turbine rotational speed Ntc ₃ (YES in step S11), the process proceeds to step S12, and time measurement by a timer is started.

In step S12, the T-ECU 12 determines whether or not the time measured by the timer has reached the waiting time t (s) ₃ . If the T-ECU 12 determines that the waiting time t (s) ₃ has not been reached (NO in step S12), it repeats step S12. On the other hand, when it is determined that the time measured by the timer has reached the waiting time t (s) ₃ (YES in step S12), the process proceeds to step S16.

  On the other hand, the T-ECU 12 determines in step S10 that the brake has not been returned, and if the process proceeds to step S13, the T-ECU 12 determines whether or not the accelerator has been returned. Specifically, when the T-ECU 12 determines that the accelerator pedal 34 is depressed immediately after the signal output from the brake sensor 27 is switched from the brake ON signal to the brake OFF signal (YES in step S13), The process proceeds to step S14. On the other hand, if it is determined that the accelerator has not been returned (NO in step S13), the process proceeds to step S4.

In step S14, T-ECU 12 is the turbine speed Nt is determined whether a reference turbine speed Ntc ₄ below. When the turbine speed Nt exceeds the reference turbine speed Ntc ₄ (NO in step S14), the T-ECU 12 repeats step S14. On the other hand, when the turbine rotational speed Nt becomes equal to or less than the reference turbine rotational speed Ntc ₄ (YES in step S14), the process proceeds to step S15, and time measurement by a timer is started.

In step S15, the T-ECU 12 determines whether or not the time measured by the timer has reached the waiting time t (s) ₄ . If the T-ECU 12 determines that the waiting time t (s) ₄ has not been reached (NO in step S15), it repeats step S15. On the other hand, if it is determined that the time measured by the timer has reached the waiting time t (s) ₄ (YES in step S15), the process proceeds to step S16.

  In step S16, the T-ECU 12 drains the hydraulic oil supplied to the B1 brake 72 and releases the B1 brake 72.

  As described above, the T-ECU 12 according to the embodiment of the present invention can change the release timing of the B1 brake 72 in accordance with the degree of the driver's start request for the vehicle 1, and therefore the degree of the start request. Accordingly, priority can be given to quickly exiting the return mode, or priority can be given to prevention of vibrations occurring in the vehicle 1. Therefore, it is possible to achieve both improvement in startability of the vehicle 1 and improvement in drivability.

Further, the release timing can be adjusted by changing the reference turbine speed Ntc _i according to the degree of the driver's start request. Therefore, the accuracy with respect to the release timing of the B1 brake 72 can be improved, and both the startability of the vehicle 1 and the improvement of drivability can be realized.

  In addition, since the driver changes the depression of the brake pedal 36 and the accelerator pedal 34 according to the start request, it is possible to accurately calculate the degree of the start request to the vehicle by the driver based on the brake pedal force and the accelerator pedal force. Become.

  Further, when the driver is required to start the vehicle 1 quickly and the brake pedal force decreases rapidly, the return mode can be shortened by setting the reference point so that the release timing of the B1 brake 72 is advanced. Become. Further, when quick start of the vehicle 1 is not required, drivability can be improved by delaying the release timing of the B1 brake 72.

Further, rapid start of the vehicle 1 is requested by the driver, when the depression of the accelerator pedal 34 is performed early, by setting the reference turbine speed Ntc _i as the release timing of the B1 brake 72 is accelerated, The return mode can be shortened. Further, when quick start of the vehicle 1 is not required, drivability can be improved by delaying the release timing of the B1 brake 72.

In the above description, when the turbine speed Nt has decreased to the reference turbine speed Ntc _i has been described for the case of starting the time measurement by the timer. However, the timer may be started according to the shift progress degree.

  In this case, the T-ECU 12 acquires the turbine rotational speed Nthold during execution of the hill hold mode.

  Further, the T-ECU 12 acquires the turbine rotational speed Nt in the return mode, and calculates the shift progress degree α from the following equation (1).

α = (Nthold−Nt) / Nthold (1)
Further, the T-ECU 12 stores in advance in the ROM the reference shift progress degree αc that starts timing by a timer in the above-described normal brake OFF return, brake release slowly return, brake ON return, and accelerator ON return.

  When the T-ECU 12 determines that the shift progress rate α has reached the reference shift progress rate αc based on the equation (1), the T-ECU 12 starts timing by the timer, and when the above-described waiting time has elapsed, the B1 brake 72 is released.

In the above description, the case where the hydraulic oil for the B1 brake 72 is drained when the waiting time t (s) _i has elapsed has been described. However, the speed at which the hydraulic oil is drained to the B1 brake 72 may be adjusted. As a result, when the time required for returning to the neutral control is likely to vary, it is possible to suppress the occurrence of vibration in the vehicle 1 by slowing the draining speed, and when the variation is difficult to occur, the draining is performed. By increasing the speed, it is possible to quickly exit the return mode.

  Further, when the accelerator is turned on, the input torque from the engine 2 increases during the return mode. Therefore, the commanded hydraulic pressure for the B1 brake 72 is increased to maintain the engagement state of the B1 brake 72 in the return mode. It may be.

  In this case, as shown in FIG. 7, the command hydraulic pressure for the B1 brake 72 is increased according to the input torque. Note that the relationship between the input torque and the command hydraulic pressure for the B1 brake 72 may be set such that the command hydraulic pressure for the B1 brake 72 increases as the input torque increases, such as a proportional function or a quadratic function.

Further, in the above description, when the return condition for terminating the neutral control is satisfied, the T-ECU 12 is any return from normal brake OFF return, brake release slowly, brake ON return, and accelerator ON return. The case where it is judged was demonstrated. However, T-ECU 12, depending on the rate of change of the amount of depression of the depression amount of the change speed and the accelerator pedal 34 of the brake pedal 36, the setting of the reference turbine speed Ntc _i may more be subdivided. In this case, the T-ECU 12 sets the reference turbine speed Ntc _i to be higher as the change speed of each depression amount is faster. Also, as the depression start of the accelerator pedal 34 is faster in the return mode at the start or the return mode may be set high standards turbine speed Ntc _i.

In the above description, the T-ECU 12 sets the waiting time t (s) _i according to the respective return states of the normal brake OFF return, the brake slow release return, the brake ON return, and the accelerator ON return. explained. However, when it is possible torque variation release timing of the B1 brake 72 by the setting of the reference turbine speed Ntc _i is to match the timing does not occur, T-ECU 12 is the wait time irrespective of the return state uniformly It may be set.

In the above description, when the T-ECU 12 determines that the return condition is satisfied in step S3 described above, the T-ECU 12 calculates the change speed with respect to the depression amount of the brake pedal 36 and whether the accelerator pedal 34 is depressed. In step S4, S7, S10 and S13 described above, which one of the normal brake OFF return, the brake slow release return, the brake ON return, and the accelerator ON return is determined based on the execution result. The case where each was judged was explained. However, the T-ECU 12 is temporarily set when the depression of the accelerator pedal 34 is detected before the return mode ends after determining that the normal brake is OFF, the brake is released slowly, or the brake is ON. The reference turbine speed Ntc _i may be reset to the reference turbine speed Ntc ₄ for returning the accelerator to ON. As a result, it is possible to respond to a quick start request of the vehicle 1.

  In the above description, the case where the T-ECU 12 executes the neutral control according to the present invention has been described. However, the present invention is not limited to this and is executed by another ECU mounted on the vehicle 1 such as the E-ECU 11. May be. A plurality of ECUs may cooperate to execute the neutral control according to the present invention.

  In the above description, the case where the control device is mounted on the front-wheel drive vehicle 1 has been described. However, the present invention is not limited to this, and the control device is mounted on a vehicle such as four-wheel drive or rear-wheel drive. It may be.

  As described above, the vehicle control device according to the present invention has the effect of achieving both improvement in vehicle startability and improvement in drivability at the end of neutral control, and neutral control. It is useful for a control device of an automatic transmission that executes

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Engine 3 Torque converter 4 Transmission mechanism 5 Automatic transmission 9 Hydraulic control circuit 11 E-ECU
12 T-ECU
DESCRIPTION OF SYMBOLS 21 Engine speed sensor 22 Intake air amount sensor 23 Intake air temperature sensor 24 Throttle sensor 25 Vehicle speed sensor 26 Cooling water temperature sensor 27 Brake sensor 28 Shift lever 29 Operation position sensor 30 Turbine speed sensor 31 Throttle valve 32 Accelerator opening sensor 33 Oil Temperature sensor 34 Accelerator pedal 36 Brake pedal 41 Output shaft 43 Impeller 44 Turbine 45 One-way clutch 46 Stator 47 Lock-up clutch 48 Input shaft 70 Output gear 71 Gear case

Claims (6)

A first engagement element that includes a transmission mechanism that outputs power input from a power source at a gear ratio corresponding to any one of a plurality of gear speeds, the gear shift mechanism being engaged when the vehicle starts. And a control device for an automatic transmission having a second engagement element to be released,
Start request detecting means for detecting a start request for the vehicle;
While the vehicle is stopped in the forward range, a hill hold mode is executed in which the engagement pressure of the first engagement element is decreased and the engagement pressure of the second engagement element is increased, and the vehicle is started when the vehicle starts. Neutral control means for engaging a first engagement element and executing a return mode for releasing the second engagement element;
The control apparatus for an automatic transmission, wherein the neutral control means sets a release timing of the second engagement element in the return mode in accordance with a degree of the start request detected by the start request detecting means. . Reference point setting means for setting a reference point for the input shaft speed of the transmission mechanism according to the degree of the start request detected by the start request detecting means,
2. The release timing according to claim 1, wherein the neutral control unit sets the time when a predetermined time has elapsed from the time when the input shaft rotation speed has decreased to the reference point set by the reference point setting unit. Control device for automatic transmission. Shift progress calculation means for calculating the shift progress in the return mode based on the input shaft speed of the transmission mechanism;
Reference point setting means for setting a reference point for the shift progress degree according to the degree of the start request detected by the start request detecting means,
The neutral control means uses the time when a predetermined time elapses from the time when the shift progress calculated by the shift progress calculating means reaches the reference point set by the reference point setting means as the release timing. The control device for an automatic transmission according to claim 1.   The control device for an automatic transmission according to claim 2 or 3, wherein the start request detecting means detects a degree of the start request based on a brake pedal force and an accelerator pedal force.   5. The control apparatus for an automatic transmission according to claim 4, wherein the reference point setting means sets the reference point so that the release timing is earlier as the decrease in the brake pedal force is faster.   The automatic transmission according to claim 4 or 5, wherein the reference point setting means sets the reference point so that the release timing is earlier as the increase in the accelerator pedal force is detected earlier. Control device.

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