JP6169838B2 - Hydraulic control device - Google Patents

Description

  The present invention relates to a hydraulic control device for an automatic transmission.

  Conventionally, as this type of hydraulic control device, one that is applied to a belt type continuously variable transmission (hereinafter referred to as CVT) and adjusts the belt clamping force by controlling the line pressure acting on each pulley is known. (For example, refer to Patent Document 1).

  In this hydraulic control device, the engine torque is calculated from the throttle opening and the engine speed, and the line pressure is controlled in accordance with the corrected engine torque obtained by subtracting the drive loss of the auxiliary equipment from the calculated engine torque.

  By the way, in recent years, a vehicle that performs idle stop control that automatically stops the engine at idle such as when the vehicle is stopped has been put into practical use.

JP 2001-304385 A

  However, in a vehicle that performs such idle stop control, when returning from idle stop control, the engine is restarted with the amount of air remaining on the intake manifold, more specifically, the intake valve downstream side when the engine is stopped.

  For this reason, for example, there is a problem that the engine torque cannot be accurately estimated based on the detected value (air amount) of an air flow sensor provided upstream of the throttle valve and the air amount estimated based on the throttle opening. .

  Therefore, when the hydraulic control device described above is applied to such a vehicle, the line pressure cannot be accurately controlled due to a decrease in the estimation accuracy of the engine torque when the engine is restarted. The same applies to the case where the line pressure control is performed based on the input torque to the automatic transmission obtained by multiplying the engine torque by the torque ratio of the torque converter.

  Specifically, when the engine is restarted, the estimated accuracy of the engine torque or the input torque is reduced, so that the estimated engine torque or the estimated input torque is reduced for the purpose of protecting various hydraulic actuators mounted on the automatic transmission. Set a higher engine torque or input torque by adding a sufficient margin. For this reason, the line pressure of the automatic transmission is set higher than the line pressure actually required.

  The present invention has been made in view of the circumstances as described above, and provides a hydraulic control device that can prevent the line pressure from becoming higher than necessary in a situation where the estimation accuracy of the input torque is reduced. With the goal.

In order to achieve the above object, the hydraulic control apparatus according to the present invention is (1) a hydraulic control apparatus that controls the hydraulic pressure of the automatic transmission based on an input torque input from the internal combustion engine to the automatic transmission via a torque converter. Estimating means for estimating a first input torque as the input torque based on an intake air amount of the internal combustion engine, and estimating a second input torque as the input torque based on a capacity coefficient of the torque converter ; and a control means for controlling the hydraulic pressure of the automatic transmission based on the previous SL minimum of said estimated by estimation means first input torque and the second input torque, said control means, It is possible to execute idle stop control that stops the internal combustion engine when a predetermined stop condition is satisfied, and restarts the internal combustion engine when a predetermined restart condition is satisfied Yes, when the accelerator opening reaches a predetermined accelerator opening when the internal combustion engine is restarted by the idle stop control, it is always the minimum value of the first input torque and the second input torque. The hydraulic pressure of the automatic transmission is controlled based on the above .

With this configuration, the hydraulic control apparatus according to the present invention is configured to always estimate the intake air amount based on the intake air amount when the accelerator opening reaches a predetermined accelerator opening when the internal combustion engine is restarted by the idle stop control . The hydraulic pressure of the automatic transmission is controlled based on the minimum value of the first input torque and the second input torque estimated based on the capacity coefficient of the torque converter. For this reason, the hydraulic control device according to the present invention controls the hydraulic pressure of the automatic transmission based on the first input torque in a region where the first input torque is lower than the second input torque. On the other hand, in a region where the second input torque is lower than the first input torque, the hydraulic pressure of the automatic transmission is controlled based on the second input torque. Therefore, the hydraulic control apparatus according to the present invention can prevent the hydraulic pressure of the automatic transmission from becoming higher than necessary in a situation where the estimation accuracy of the input torque is lowered.

The hydraulic control device according to the present invention is the hydraulic control device according to (1 ), wherein ( 2 ) the estimation means includes a detection result of an air amount detection unit that detects the intake air amount, and an engine of the internal combustion engine. It is preferable to estimate the first input torque based on a detection result of an engine rotation speed detection unit that detects a rotation speed.

The hydraulic control device according to the present invention is the hydraulic control device according to (1) or (2) , wherein ( 3 ) the estimation means includes a capacity coefficient of the torque converter and a maximum value when the internal combustion engine is restarted. The second input torque is preferably estimated based on the engine speed.

  ADVANTAGE OF THE INVENTION According to this invention, the hydraulic control apparatus which can prevent that a line pressure becomes higher than necessary under the condition where the estimation precision of input torque falls can be provided.

It is a schematic block diagram of the power train of the vehicle provided with the hydraulic control apparatus which concerns on embodiment of this invention. 1 is a schematic configuration diagram of an engine according to an embodiment of the present invention. It is a belt clamping pressure map regarding control of the belt clamping pressure of CVT which concerns on embodiment of this invention. It is a flowchart which shows the line pressure calculation process performed by ECU which concerns on embodiment of this invention. It is a flowchart which shows the engine torque estimation process in step S6 of FIG. It is a graph which shows the engine torque estimated in embodiment of this invention.

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

  In the present embodiment, a case will be described in which the hydraulic control device according to the present invention is applied to a vehicle in which a torque converter with a lockup clutch is mounted between an internal combustion engine such as an engine and an automatic transmission.

  In the present embodiment, an example in which a continuously variable transmission (hereinafter simply referred to as CVT) is employed as an automatic transmission will be described.

  First, referring to FIG. 1, a power train of a vehicle equipped with a hydraulic control device according to an embodiment of the present invention will be described.

  As shown in FIG. 1, the power train 10 includes an engine 1 as an internal combustion engine, a torque converter 2, a forward / reverse switching device 3, a CVT 4, a differential gear 5, a hydraulic control circuit 100, an electronic control unit ( (Electronic Control Unit: hereinafter simply referred to as ECU) 200.

  As shown in FIG. 2, the engine 1 includes a cylinder block 11, a cylinder head 12 fixed to the upper portion of the cylinder block 11, and an oil pan 13 that stores oil. The cylinder block 11, the cylinder head 12, Thus, a plurality of cylinders 14 are formed.

  In the present embodiment, the engine 1 is assumed to be an in-line four-cylinder engine, but in the present invention, an in-line six-cylinder engine, a V-type six-cylinder engine, a V-type twelve-cylinder engine, or a horizontally opposed six-cylinder engine. You may be comprised by various types of engines, such as a cylinder engine. The engine 1 shown in FIG. 2 shows one cylinder 14 out of four cylinders arranged in series.

  A piston 15 is accommodated in the cylinder 14 so as to be able to reciprocate, and a combustion chamber 16 of each cylinder 14 is formed by the cylinder block 11, the cylinder head 12, and the piston 15. In the present embodiment, the engine 1 is described as being constituted by a four-cycle engine that performs a series of four strokes including an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke while the piston 15 reciprocates twice. To do.

  The piston 15 accommodated in each cylinder 14 is connected to a crankshaft 18 via a connecting rod 17. The connecting rod 17 converts the reciprocating motion of the piston 15 into the rotational motion of the crankshaft 18. The crankshaft 18 is connected to the input shaft of the torque converter 2.

  Therefore, the engine 1 causes the piston 15 to reciprocate by combusting a mixture of fuel and air in the combustion chamber 16 and rotate the crankshaft 18 via the connecting rod 17 to thereby generate the torque converter 2 (see FIG. 1). ) To transmit power. The power of the engine 1 transmitted to the torque converter 2 is transmitted to the differential gear 5 via the forward / reverse switching device 3, the input shaft 4a, and the CVT 4, and is distributed to left and right drive wheels (not shown) (see FIG. 1).

  In addition, although the fuel used for the engine 1 is gasoline, it may replace with gasoline and the alcohol fuel which mixed alcohol and gasoline, such as hydrocarbon fuels, such as light oil, and ethanol.

  The engine 1 is provided with an intake pipe 30 connected to the cylinder head 12 for introducing air into the combustion chamber 16. The intake pipe 30 includes an air cleaner 31 that cleans air flowing from outside the vehicle, an air flow sensor 32 that detects a flow rate of air introduced into the combustion chamber 16, that is, an intake air amount, and a throttle valve that adjusts the intake air amount. 33 is provided.

  The air cleaner 31 is configured to remove foreign substances in the intake air by using, for example, a paper or synthetic fiber nonwoven fabric filter accommodated therein. The air flow sensor 32 is provided on the upstream side of the throttle valve 33 and outputs a detection signal indicating the intake air amount to the ECU 200. The air flow sensor 32 in the present embodiment constitutes an air amount detection unit according to the present invention.

  The throttle valve 33 is constituted by a thin disc-like valve body, and includes a shaft at the center of the valve body. The throttle valve 33 is provided with a throttle valve actuator 34 that rotates the valve body by rotating the shaft in accordance with the control of the ECU 200 and adjusts the intake air amount to the throttle valve 33.

  Further, the engine 1 is provided with an exhaust pipe 35 connected to the cylinder head 12 in order to exhaust the exhaust gas generated by the combustion of the air-fuel mixture in the combustion chamber 16 to the outside of the vehicle. The exhaust pipe 35 is provided with a catalyst 36 for oxidation-reduction purification of harmful substances in the exhaust gas.

  The cylinder head 12 is formed with an intake port 37 for communicating the intake pipe 30 and the combustion chamber 16 and an exhaust port 38 for communicating the combustion chamber 16 and the exhaust pipe 35.

  The cylinder head 12 has an intake valve 51 for controlling the introduction of combustion air from the intake pipe 30 to the combustion chamber 16 and an exhaust gas for controlling the discharge of exhaust gas from the combustion chamber 16 to the exhaust pipe 35. An exhaust valve 52, an injector 53 for injecting fuel into the combustion chamber 16, and a spark plug 54 for igniting the air-fuel mixture in the combustion chamber 16 are provided.

  The injector 53 has a solenoid coil and a needle valve that are controlled by the ECU 200. Fuel is supplied to the injector 53 at a predetermined pressure. When the solenoid coil is energized by the ECU 200, the injector 53 opens the needle valve and injects fuel into the combustion chamber 16.

  The spark plug 54 is constituted by a known spark plug having an electrode made of platinum or an iridium alloy. The spark plug 54 is discharged when the electrode is energized by the ECU 200 and ignites the air-fuel mixture in the combustion chamber 16.

  As shown in FIG. 1, the torque converter 2 includes a pump impeller 21p connected to the crankshaft 18 and a turbine impeller 21t connected to the forward / reverse switching device 3 via the turbine shaft 2a. Power transmission is performed through this.

  A lock-up clutch 22 is provided between the pump impeller 21p and the turbine impeller 21t of the torque converter 2. Further, an engagement side oil chamber 24 and a release side oil chamber 25 divided by the piston 23 are formed inside the torque converter 2.

  The lockup clutch 22 is engaged or released when the hydraulic pressure supply to the engagement side oil chamber 24 and the release side oil chamber 25 is switched by a switching valve or the like of the hydraulic control circuit 100 described later.

  When the lockup clutch 22 is engaged, the crankshaft 18 and the turbine shaft 2a are directly connected, and the power output from the engine 1 is directly transmitted to the CVT 4 side without passing through the fluid in the torque converter 2. On the other hand, when the lockup clutch 22 is released, the power output from the engine 1 is transmitted to the CVT 4 side via the fluid.

  The pump impeller 21p is provided with an oil pump 26 that operates according to the rotation of the pump impeller 21p. The oil pump 26 is configured by a mechanical oil pump such as a gear pump, for example, and supplies hydraulic pressure to the hydraulic control circuit 100.

  The forward / reverse switching device 3 is provided in a power transmission path between the torque converter 2 and the CVT 4 and is mainly composed of a double pinion type planetary gear device. The forward / reverse switching device 3 includes a forward clutch C1 and a reverse brake B1 that are configured by a hydraulic friction engagement device that is frictionally engaged by a hydraulic cylinder.

  The forward / reverse switching device 3 is brought into an integral rotation state by engaging the forward clutch C1 and releasing the reverse brake B1. At this time, the forward power transmission path is established, and the forward driving force is transmitted to the CVT 4 side.

  On the other hand, when the reverse brake B1 is engaged and the forward clutch C1 is released, the forward / reverse switching device 3 sets the reverse power transmission path for rotating the input shaft 4a in the reverse direction with respect to the turbine shaft 2a. Establish. Thereby, the driving force in the reverse direction is transmitted to the CVT 4 side.

  Further, when both the forward clutch C1 and the reverse brake B1 are released, the forward / reverse switching device 3 is set to a neutral state (blocked state) in which power transmission is blocked.

  The CVT 4 includes an input-side primary pulley 41 having a variable effective diameter, an output-side secondary pulley 42 having a variable effective diameter, and a metal transmission belt (belt) 43 wound around these pulleys. Yes. The CVT 4 transmits power via a friction force between a primary pulley 41 provided on the input shaft 4a and a secondary pulley 42 provided on the output shaft 4b and the transmission belt 43. The CVT 4 is connected to the engine 1 via a forward / reverse switching device 3 and a lockup clutch 22.

  The primary pulley 41 and the secondary pulley 42 are fixed to the input shaft 4a and the output shaft 4b, respectively, and fixed to the input shaft 4a and the output shaft 4b. A movable sheave 41b and a movable sheave 42b are provided so as to be movable.

  The primary pulley 41 changes the winding radius of the transmission belt 43 by changing the groove width. The secondary pulley 42 generates a belt clamping pressure that clamps the transmission belt 43. The transmission belt 43 is wound around a V-shaped pulley groove formed by the fixed sheaves 41a and 42a and the movable sheaves 41b and 42b.

  Moreover, the primary pulley 41 and the secondary pulley 42 have hydraulic actuators 45 and 46 for moving the movable sheaves 41b and 42b in the axial direction, respectively. The hydraulic actuators 45 and 46 are constituted by, for example, hydraulic cylinders.

  The primary pulley 41 and the secondary pulley 42 continuously change the width of the pulley groove by controlling the hydraulic pressure supplied to the hydraulic actuators 45 and 46. Thereby, the winding radius of the transmission belt 43 is changed, and the transmission gear ratio is continuously changed.

  The hydraulic control circuit 100 includes a shift speed control unit 110, a belt clamping pressure control unit 120, a line pressure control unit 130, a lockup engagement pressure control unit 140, a clutch pressure control unit 150, and a manual valve 160. Have.

  The shift speed control unit 110 controls the hydraulic pressure supplied to the hydraulic actuator 45 of the primary pulley 41 according to the hydraulic pressure output from the first solenoid valve 111 for shift control and the second solenoid valve 112 for shift control. That is, the transmission speed control unit 110 controls the transmission ratio of the CVT 4 through hydraulic pressure control.

  The belt clamping pressure control unit 120 controls the hydraulic pressure supplied to the hydraulic actuator 46 of the secondary pulley 42 according to the hydraulic pressure output from the belt clamping pressure control linear solenoid valve 121. That is, the belt clamping pressure control unit 120 controls the belt clamping pressure through the control of the hydraulic pressure.

  The line pressure control unit 130 controls the line pressure according to the hydraulic pressure output from the line pressure control linear solenoid valve 131. The line pressure refers to the hydraulic pressure supplied by the oil pump 26 and regulated by a regulator valve (not shown). Further, the line pressure in the present embodiment corresponds to the “hydraulic pressure of the automatic transmission” in the present invention.

  The lockup engagement pressure control unit 140 controls the engagement force, that is, the transmission torque of the lockup clutch 22 in accordance with the hydraulic pressure output from the lockup engagement pressure control linear solenoid valve 141. The lockup clutch 22 is controlled to any one of a released state, an engaged state, and a slip state (an intermediate state between the released state and the engaged state) according to the magnitude of the transmission torque.

  The manual valve 160 operates in conjunction with the operation of the shift lever 8 by the driver, and switches the oil passage.

  The clutch pressure control unit 150 controls the hydraulic pressure supplied from the manual valve 160 to the input clutch C1 or the reverse brake B1 according to the hydraulic pressure output from the line pressure control linear solenoid valve 131.

  The first solenoid valve 111 for shift control, the second solenoid valve 112 for shift control, the linear solenoid valve 121 for belt clamping pressure control, the linear solenoid valve 131 for line pressure control, and the linear solenoid valve 141 for lockup engagement pressure control described above. Are respectively connected to the ECU 200. A control signal is supplied from the ECU 200 to each of these linear solenoid valves.

  Each linear solenoid valve controls each hydraulic actuator that is a control target by controlling the hydraulic pressure output from each control unit by outputting a control hydraulic pressure in accordance with a control signal from the ECU 200. In other words, the first solenoid valve 111 for shift control and the second solenoid valve 112 for shift control are used for shift control for controlling the gear ratio of the CVT 4. The belt clamping pressure control linear solenoid valve 121 is used for belt clamping pressure control of the transmission belt 43. The line pressure control linear solenoid valve 131 is used to control the line pressure. Further, the lockup engagement pressure control linear solenoid valve 141 is used for the engagement pressure control of the lockup clutch 22.

  For example, the line pressure control linear solenoid valve 131 outputs a control hydraulic pressure to the line pressure control unit 130 and the clutch pressure control unit 150 in accordance with a current value determined by a duty value output from the ECU 200.

  The belt clamping pressure control linear solenoid valve 121 outputs a control hydraulic pressure to the belt clamping pressure control unit 120 in accordance with a current value determined by a duty value output from the ECU 200.

  Here, the belt clamping pressure control unit 120 is supplied with a line pressure that is fed from the oil pump 26 and regulated. The belt clamping pressure control unit 120 adjusts the hydraulic pressure supplied to the hydraulic actuator 46 in accordance with the increase or decrease of the control hydraulic pressure output from the belt clamping pressure control linear solenoid valve 121.

  Specifically, the belt clamping pressure control unit 120 is configured by a clamping pressure control valve, and continuously regulates the line pressure using the control hydraulic pressure from the linear solenoid valve 121 for belt clamping pressure control as a pilot pressure. The belt clamping pressure Pd is output. For example, as shown in FIG. 3, the gear ratio γ and the required hydraulic pressure (target belt clamping pressure) that are experimentally obtained and stored in advance so that belt slip does not occur using the input torque Tin of the CVT 4 corresponding to the transmission torque as a parameter. The belt clamping pressure Pd to the hydraulic actuator 46 is regulated according to the relationship (corresponding to the above) (belt clamping map). The belt clamping pressure, that is, the friction force between the primary pulley 41 and the secondary pulley 42 and the transmission belt 43 is increased or decreased according to the belt clamping pressure Pd.

  Thus, the belt clamping pressure is increased or decreased by adjusting the line pressure by using the control hydraulic pressure output from the belt clamping pressure control linear solenoid valve 121 as a pilot pressure and supplying it to the hydraulic actuator 46.

  The ECU 200 includes a microcomputer including, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an input / output interface, and the like. The CPU has a temporary storage function of the RAM. The signal processing is performed according to a program that is used and stored in advance in the ROM. Various control constants and various maps are stored in advance in the ROM.

  The ECU 200 includes a vehicle speed sensor 201, an accelerator opening sensor 202, an engine rotation speed sensor 203, a turbine rotation speed sensor 204, a primary pulley rotation speed sensor 205, a secondary pulley rotation speed sensor 206, a brake sensor 207, and a shift position sensor 208. Various sensors such as are connected.

  The vehicle speed sensor 201 detects the vehicle speed V. The accelerator opening sensor 202 detects the operation amount of the accelerator pedal, that is, the accelerator opening Acc. The engine rotation speed sensor 203 detects the rotation speed of the pump impeller 21p to which the rotation of the engine 1 is transmitted as the engine rotation speed Ne. The engine rotation speed Ne corresponds to the engine rotation speed in the present invention. Further, the engine rotation speed sensor 203 in the present embodiment constitutes engine rotation speed detection according to the present invention.

  The turbine rotational speed sensor 204 detects the rotational speed of the turbine shaft of the torque converter 2, that is, the turbine rotational speed Nt. The primary pulley rotation speed sensor 205 detects the rotation speed of the primary pulley 41, that is, the primary pulley rotation speed Nin. The secondary pulley rotational speed sensor 206 detects the rotational speed of the secondary pulley 42, that is, the secondary pulley rotational speed Nout.

  The brake sensor 207 detects the amount of depression of the brake pedal. The shift position sensor 208 detects the operation position of the shift lever 8, that is, the shift position. Examples of the shift position include a “D range” for forward travel, an “N range” for a neutral position, and an “R range” for reverse travel.

  ECU 200 outputs a control signal to each solenoid valve of hydraulic control circuit 100 based on the detection signal input from each sensor. Thereby, the control oil pressure output from each solenoid valve is adjusted. ECU 200 in the present embodiment constitutes a control means according to the present invention.

  In addition, the ECU 200 performs an idle stop control that automatically stops the engine 1 when a predetermined stop condition is satisfied, and automatically restarts the engine 1 when a predetermined restart condition is satisfied. This idle stop control is executed to improve fuel consumption, reduce exhaust gas, reduce noise, etc. when the vehicle is stopped at an intersection or the like.

  For example, the ECU 200 temporarily controls the engine 1 by executing a control for closing the throttle valve 33 by the throttle valve actuator 34, a control for stopping the fuel supply from the injector 53, or the like when both predetermined stop conditions are satisfied. Automatically stops. On the other hand, when any one of the predetermined restart conditions is satisfied, ECU 200 restarts engine 1 by restarting the fuel supply from injector 53 or the like.

  Here, the predetermined stop condition is, for example, a zero determination value (meaning a substantially zero value including zero) for determining that the shift position is in the D range or the accelerator opening degree Acc is zero. Or whether the brake pedal is depressed or whether the vehicle speed V is a zero determination value (which means a substantially zero value including zero) for determining that the vehicle speed V is zero. Further, as the predetermined restart condition, for example, when the vehicle is stopped when the shift position is in the D range, the accelerator opening Acc becomes a value that is not set to the zero determination value, that is, whether the accelerator is turned on or the brake pedal is depressed. A condition such as whether or not the brake is released, that is, whether or not the brake is off is included.

  Further, for example, the ECU 200 correlates with the intake air amount Ga (or the intake air amount Ga) from a relationship map between the engine rotational speed Ne and the engine torque Te that is experimentally obtained and stored in advance using the intake air amount Ga as a parameter. The engine torque Te_1 is estimated based on a certain throttle opening) and the engine speed Ne.

  The ECU 200 calculates the input torque Tin_1 input from the engine 1 to the CVT 4 via the torque converter 2 by multiplying the estimated engine torque Te_1 by the torque ratio t of the torque converter 2. . That is, the ECU 200 estimates the input torque Tin_1 based on the intake air amount Ga of the engine 1. The input torque Tin_1 corresponds to the first input torque according to the present invention.

  The torque ratio t described above is a function of the speed ratio e of the torque converter 2 (= turbine rotational speed Nt / pump rotational speed Np (engine rotational speed Ne)). Is calculated by the ECU 200 based on the actual speed ratio e from a relationship (map) (not shown) that is obtained and stored.

  In the present embodiment, such an estimation method of the input torque Tin based on the intake air amount Ga is referred to as a first input torque estimation method.

  On the other hand, the ECU 200 estimates the input torque Tin_2 by the second input torque estimation method in addition to the first input torque estimation method when the engine is restarted when returning from the above-described idle stop control. It has become. The two methods for estimating the input torque Tin are provided in the situation where the estimation accuracy of the input torque Tin is lowered as will be described later (for example, when the engine is restarted when returning from idle stop control). This is because the line pressure controlled based on the input torque Tin is set to an optimum value.

In the second input torque estimation method, the ECU 200 estimates the input torque Tin_2 based on the capacity coefficient C of the torque converter 2. Here, the input torque Tin_2 is the maximum torque generated Te_2 value obtained by multiplying the torque ratio t is _max when the engine restart at the time of return from the idling stop control. The maximum generated torque Te_2 _max is obtained when the engine speed Ne is increased from the stall torque (maximum engine torque) at the maximum engine speed Ne _max when the engine is restarted, which is calculated using the capacity coefficient C of the torque converter 2. The value obtained by subtracting the inertia loss. The maximum engine speed Ne _max is the maximum engine speed set when the engine 1 is restarted. Therefore, when the engine is restarted, the engine speed Ne is controlled in a range that is equal to or lower than the maximum engine speed Ne _max .

  Specifically, ECU 200 calculates turbine torque Tt (= input torque Tin_2) output from torque converter 2 based on the torque converter characteristics of torque converter 2 that have been experimentally obtained and stored in advance. The above-mentioned torque converter characteristics indicate the relationship between the speed ratio e, the torque ratio t, and the capacity coefficient C.

That is, ECU 200 first calculates capacity coefficient C when speed ratio e = 0 (torque ratio t = maximum) based on the above-described torque converter characteristics. Next, the ECU 200 calculates the pump torque Tp (engine torque Te_2) based on the calculated capacity coefficient C and the maximum engine speed Ne _max, and inertia loss when increasing the calculated pump torque Tp and the engine speed Ne. Then, the turbine torque Tt (= input torque Tin_2) is calculated from the maximum torque ratio t corresponding to the speed ratio e = 0.

In other words, the ECU 200 calculates the pump torque Tp, that is, the engine torque Te_2 (= (Ne _max ) ² × C) by multiplying the value obtained by squaring the maximum engine speed Ne _max by the calculated capacity coefficient C. The maximum generated torque Te_2 _max is calculated by subtracting the inertia loss described above from the engine torque Te_2. Then, ECU 200 calculates the turbine torque Tt (= input torque Tin_2) by multiplying the torque ratio t is the maximum torque generated _{Te_2 max} the calculated.

  The ECU 200 estimates the minimum value of the input torque Tin_1 and the input torque Tin_2 calculated (estimated) by the two input torque estimation methods described above as the input torque Tin when the engine 1 is restarted by the idle stop control. The line pressure is controlled based on the estimated input torque Tin (= min (Tin_1, Tin_2)). Therefore, ECU 200 in the present embodiment constitutes an estimation means according to the present invention.

Specifically, the ECU 200 sets the target belt clamping pressure Pd _tgt from the estimated input torque Tin and the gear ratio γ based on, for example, the belt clamping pressure map shown in FIG. The ECU 200 controls the belt clamping pressure control linear solenoid valve 121 so that the set target belt clamping pressure Pd _tgt is obtained. That is, the ECU 200 controls the belt clamping pressure Pd by controlling the line pressure by operating the belt clamping pressure control linear solenoid valve 121 according to the estimated input torque Tin. .

  Next, the operation will be described.

  The ECU 200 is configured to execute the following line pressure calculation processing at predetermined time intervals.

  As shown in FIG. 4, ECU 200 determines whether or not a predetermined stop condition related to the idle stop control is satisfied during operation of engine 1 (step S1). Since the predetermined stop condition is as described above, the description is omitted here. When it is determined that the predetermined stop condition is not satisfied, ECU 200 repeats this step again.

  On the other hand, when it is determined that the predetermined stop condition is satisfied, the ECU 200 executes idle stop control (step S2). Specifically, ECU 200 closes throttle valve 33 and stops the supply of fuel to engine 1 to stop engine 1.

  Next, ECU 200 determines whether or not a predetermined restart condition is satisfied during execution of the idle stop control (step S3). Since the predetermined restart condition is as described above, description thereof is omitted here. When ECU 200 determines that the predetermined restart condition is not satisfied, it repeats this step again.

  On the other hand, when it is determined that a predetermined restart condition is satisfied, ECU 200 restarts engine 1 (step S4). Specifically, the ECU 200 restarts the engine 1 by restarting the fuel supply from the injector 53 or the like.

  Then, ECU 200 determines whether or not the idle determination is ON (step S5). The ECU 200 can make an idle determination based on whether or not the accelerator opening Acc has reached a predetermined accelerator opening (for example, Acc = 0), or whether the idle switch is ON. For example, the ECU 200 sets the idle determination flag to ON when the accelerator opening Acc reaches a predetermined accelerator opening (for example, Acc = 0), and determines the idle while the idle determination flag is kept ON. Is determined to be ON.

  If the ECU 200 determines that the idle determination is not ON, the ECU 200 calculates the input torque Tin_1 based on the intake air amount Ga without going through steps S6 to S8 described later, and estimates this as the input torque Tin to the CVT 4. Then, the line pressure is controlled in accordance with the estimated input torque Tin (step S10).

  On the other hand, when it is determined that the idle determination is ON, the ECU 200 executes an input torque estimation process (step S6). Here, with reference to FIG. 5, the detail of the above-mentioned input torque estimation process is demonstrated.

  As shown in FIG. 5, when the ECU 200 determines that the idle determination is ON, the ECU 200 calculates the input torque Tin_1 based on the intake air amount Ga (step S61). Next or simultaneously with step S61, the ECU 200 calculates the input torque Tin_2 based on the capacity coefficient C of the torque converter 2 (step S62). A specific method for calculating the input torque Tin_1 and the input torque Tin_2 is as described above.

  Next, the ECU 200 selects the minimum value of the input torque Tin_1 and the input torque Tin_2, estimates this as the input torque Tin (= min (Tin_1, Tin_2)) to the CVT 4 (step S63), and performs this process. finish.

  Returning to FIG. 4, the ECU 200 controls the line pressure according to the input torque Tin estimated in the input torque estimation process of FIG. 5 (step S <b> 7). In the present embodiment, the line pressure is controlled to a value corresponding to the input torque Tin estimated in the input torque estimation process in step S6 until a reset condition described later is satisfied.

  Next, the ECU 200 determines whether or not a reset condition is satisfied (step S8). Here, the reset condition is a condition for ending the control of the line pressure using the input torque Tin estimated by the input torque estimation process of FIG. 5. For example, (1) idle determination is turned off. (2) The engine rotational speed Ne has become a predetermined value or more, (3) Neutral control that is automatically switched to the neutral state while the vehicle is stopped in the D range, (4) For example, a shift lever 8 (see FIG. 1) includes the fact that a garage shift is performed to switch from the D range to another range, and (5) that a predetermined time has elapsed since the engine restart in step S4. Such reset conditions are arbitrarily set, and are not limited to the above-described conditions.

  Therefore, the ECU 200 determines that the reset condition is satisfied when at least one of the reset conditions (1) to (5) is satisfied, and the input torque in step S6 described above. The calculation of the line pressure according to the input torque Tin estimated by the estimation process is terminated. Therefore, the input torque estimation process is repeated until the reset condition is satisfied, and the line pressure is calculated according to the input torque Tin estimated by the input torque estimation process.

  When the ECU 200 determines that the reset condition is satisfied, the ECU 200 determines that the estimation accuracy of the input torque Tin is not reduced, calculates the input torque Tin_1 based on the intake air amount Ga, and supplies this to the CVT 4. The input torque Tin is estimated (step S9). Then, the ECU 200 controls the line pressure according to the input torque Tin estimated based on the intake air amount Ga (step S10).

  Next, the operation of the hydraulic control apparatus according to the present embodiment will be described with reference to FIG.

  FIG. 6 shows time on the horizontal axis, whether or not the idle stop control is executed, the engine speed Ne, the input torque Tin_1, Tin_2, the actual input torque Tin_r, and the line pressure in the present embodiment and the conventional line pressure. It is a thing. Here, the actual input torque Tin_r is obtained by multiplying the actual engine torque Ter by the torque ratio t.

As shown in FIG. 6, when a predetermined restart condition is satisfied and an engine restart request is made during execution of the idle stop control, the idle stop control is turned off and the engine speed Ne is The maximum engine speed Ne _{max is} increased. Thereafter, the engine rotational speed Ne decreases to the _idle rotational speed Ne _idle or becomes a rotational speed corresponding to the accelerator opening degree Acc.

  At this time, the input torques Tin_1 and Tin_2 calculated in the input torque estimation process shown in FIG. 5 change as shown in FIG. That is, the input torque Te_1 calculated based on the intake air amount Ga changes at a higher value than the input torque Tin_2 calculated based on the capacity coefficient C of the torque converter 2 from when the engine restart request is made. The characteristic decreases as the actual input torque Tin_r decreases.

  On the other hand, the input torque Tin_2 is held at a constant value that is lower than the input torque Te_1 since the engine restart request was made. Conventionally, the line pressure is controlled according to the input torque Te_1 that is higher than the maximum value of the actual input torque Tin_r even when the engine is restarted when returning from the idle stop control. For this reason, as shown by the broken line in FIG. 6, the line pressure is controlled to be high.

  On the other hand, in the present embodiment, the minimum value of the input torques Tin_1 and Tin_2 is used as the input torque Tin used for controlling the line pressure when the engine is restarted when returning from the idle stop control. did. Therefore, in the region where the input torque Tin_1 is higher than the input torque Tin_2 after the engine restart request is made, the input torque Tin_2 that is the minimum value of the input torque Tin_1 and Tin_2, which is close to the actual input torque Tin_r, is the line pressure. It is used as the input torque Tin used for the control of (as shown by the solid line in the figure).

  Thereafter, in a region where the input torque Tin_1 becomes lower than the input torque Tin_2 as the actual input torque Tin_r decreases, the input torque Tin_1 is used as the input torque Tin used for controlling the line pressure (shown by a solid line in the figure). Street). Thereby, as shown by the solid line in FIG. 6, the line pressure is reduced particularly in a region where the input torque Tin_1 is higher than the input torque Tin_2 as compared with the conventional line pressure shown by the broken line in FIG. 6. . Further, the input torque Tin used for the control of the line pressure approaches the actual input torque Tin_r, and the estimation accuracy of the input torque Tin is improved as compared with the conventional case.

  As described above, the hydraulic control apparatus according to the present embodiment has the first input torque Tin_1 estimated based on the intake air amount Ga and the second input torque estimated based on the capacity coefficient C of the torque converter 2. The line pressure is controlled based on the minimum value of Tin_2.

  For this reason, the hydraulic control apparatus according to the present embodiment controls the line pressure based on the first input torque Tin_1 in a region where the first input torque Tin_1 is lower than the second input torque Tin_2. On the other hand, in a region where the second input torque Tin_2 is lower than the first input torque Tin_1, the line pressure is controlled based on the second input torque Tin_2.

  Therefore, the hydraulic control apparatus according to the present embodiment prevents the line pressure from becoming unnecessarily high when the engine is restarted when returning from idle stop control, for example, in a situation where the estimation accuracy of the input torque Tin decreases. can do.

  Thereby, the hydraulic control apparatus according to the present invention can prevent the load on the transmission belt 43 from increasing due to the deterioration of fuel consumption or the increase of the belt clamping pressure.

  In the present embodiment, in step S5 in the line pressure calculation process executed by the ECU 200, it is determined whether or not the idle determination is ON. However, this step may be omitted. In this case, it is preferable to remove from the reset condition that the above-described (1) idle determination is turned off in accordance with omission of step S5.

  In the present embodiment, an example in which the hydraulic control device according to the present invention is applied to a vehicle equipped with a CVT 4 as an automatic transmission has been described. However, the present invention is not limited to this, and the hydraulic control device according to the present invention is stepped. You may apply to the vehicle which mounts a type automatic transmission. In this case, the line pressure controlled by the hydraulic control device according to the present embodiment is a hydraulic pressure source for engaging and releasing a plurality of friction engagement elements. In this stepped automatic transmission, by controlling the line pressure described above, a plurality of gears with different gear ratios are established by selectively engaging or releasing a plurality of friction engagement elements. ing. Even in a vehicle equipped with such a stepped automatic transmission, it is possible to prevent the line pressure from becoming higher than necessary by applying the hydraulic control device according to the present embodiment. Loss can be suppressed and fuel consumption can be improved.

  As described above, the hydraulic control apparatus according to the present invention can prevent the line pressure from becoming higher than necessary under the condition that the estimation accuracy of the input torque is reduced, and the hydraulic control apparatus for an automatic transmission Useful.

DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine), 2 ... Torque converter, 4 ... CVT (automatic transmission), 32 ... Air flow sensor (air amount detection part), 43 ... Transmission belt (belt), 100 ... Hydraulic control circuit, 130 ... Line Pressure controller, 131 ... Linear solenoid valve for line pressure control, 200 ... ECU (estimating means, control means), 203 ... Engine rotational speed sensor (engine rotational speed detecting section), Tin_1 ... Input torque (first input torque) , Tin_2 ... Input torque (second input torque)

Claims (3)

A hydraulic control device for controlling the hydraulic pressure of the automatic transmission based on an input torque input from the internal combustion engine to the automatic transmission via a torque converter,
Estimating means for estimating a first input torque as the input torque based on an intake air amount of the internal combustion engine, and estimating a second input torque as the input torque based on a capacity coefficient of the torque converter ;
And a control means for controlling the hydraulic pressure of the automatic transmission based on the previous SL minimum of said estimated by estimation means first input torque and the second input torque,
The control means can execute idle stop control for stopping the internal combustion engine when a predetermined stop condition is satisfied, and restarting the internal combustion engine when a predetermined restart condition is satisfied,
At the time of restart of the internal combustion engine by the idle stop control, when the accelerator opening reaches a predetermined accelerator opening, it is always based on the minimum value of the first input torque and the second input torque. A hydraulic control device for controlling the hydraulic pressure of the automatic transmission . The estimation means estimates the first input torque based on a detection result of an air amount detection unit that detects the intake air amount and a detection result of an engine rotation speed detection unit that detects an engine rotation speed of the internal combustion engine. The hydraulic control device according to claim 1 . The said estimation means estimates the said 2nd input torque based on the capacity | capacitance coefficient of the said torque converter and the largest engine speed at the time of the restart of the said internal combustion engine, The Claim 1 or Claim 2 characterized by the above-mentioned. The hydraulic control device described.

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