WO2014112603A1

WO2014112603A1 - Lock-up-clutch control device and control method

Info

Publication number: WO2014112603A1
Application number: PCT/JP2014/050853
Authority: WO
Inventors: 圭一朗草部; 小林　靖彦; 仁伊澤
Original assignee: アイシン・エィ・ダブリュ株式会社
Priority date: 2013-01-18
Filing date: 2014-01-17
Publication date: 2014-07-24

Abstract

A transmission ECU for controlling a lock-up clutch uses the difference (u*-u) between a target slip speed (u*) and an actual slip speed (u), proportional term gain (Kp), and integral term gain (Ki) to set (S150) a feedback term (FB) for an oil-pressure command value (Up), said feedback term (FB) including a proportional term (FBp) and an integral term (FBi), and uses the oil-pressure command value (Up) including the feedback term (FB) to implement (S160, S170) slip control which causes the actual slip speed (u), i.e. the difference in actual rotational speed between an engine and an input shaft of an automatic transmission, to match the target slip speed (u*). When implementing the slip control, the actual slip speed (u) is calculated (S130), and at least the integral term gain (Ki) is changed (S140) in accordance with the actual slip speed (u).

Description

Control device and control method for lock-up clutch

The present invention relates to a control device and a control method for a lock-up clutch capable of connecting a prime mover of a vehicle and an input shaft of a transmission and releasing the connection therebetween.

Conventionally, as a control device that performs slip control that matches the actual slip speed (actual rotational speed difference) between the prime mover and the input shaft of the transmission with the target slip speed, the low frequency region of the deviation between the target slip rotation and the actual slip rotation is A first feedback compensator (proportional derivative (PD) controller) that has a frequency characteristic in which the gain is set smaller than the gain in the high frequency region and outputs the first slip rotation command value by inputting the deviation; A second feedback compensator (proportional integral derivative) that has a frequency characteristic in which the gain of the deviation in the low frequency region is set larger than the gain in the high frequency region, and outputs the second slip rotation command value by inputting the deviation. (PID) controller) is known (for example, see Patent Document 1).

In order to improve the transient response characteristic of the slip control at the start of the vehicle, the control device determines the magnitude of the response delay of the clutch hydraulic pressure at the start of the vehicle, that is, the control amount that determines the torque capacity of the lockup clutch. Switching from feedback control by the first feedback compensator to feedback control by the second feedback compensator is performed. When switching the feedback compensator, the weighting of the first slip rotation command value and the second slip rotation command value with respect to the slip rotation command value is gradually changed. The control amount for determining the torque capacity of the lockup clutch includes the differential pressure between the apply pressure and the release pressure acting on the lockup clutch, and the lockup clutch torque estimated from the engine torque and the engine speed. A capacity or the like is used. Patent Document 1 also uses a map that predefines a region for switching between feedback control by the first feedback compensator and feedback control by the second feedback compensator using the engine torque and the engine speed as arguments. Are listed.

JP 2010-270822 A

If the slip control as described above is executed not only when the vehicle starts, but also when the vehicle is accelerating or decelerating, or even during shifting, the transmission efficiency of the power through the lock-up clutch and the engine (primary motor) ) Can improve fuel economy. However, the characteristics of the lock-up clutch as the object to be controlled change continuously according to the state of the vehicle and the engine. For this reason, in the control device described in Patent Document 1, the feedback control by the first feedback compensator and the feedback control by the second feedback compensator are switched according to the state of the vehicle or the engine, or the state of the vehicle or the like. Even if the weighting of the first slip rotation command value and the second slip rotation command value is gradually changed according to the above, the characteristics (gains) of the first and second feedback compensators themselves are not changed. In addition, since it is not easy to appropriately change the weighting according to the state of the vehicle or the like, it is difficult to improve the responsiveness of the slip control while stably executing the slip control.

Therefore, the main object of the present invention is to enable slip control to be executed stably and responsively under various circumstances.

A control device for a lock-up clutch according to the present invention includes:
A hydraulic impulsive command value to a lock-up clutch constituting a starting device together with a pump impeller coupled to a vehicle prime mover and a turbine runner coupled to an input shaft of a transmission is the difference in actual rotational speed between the prime mover and the input shaft. In a lockup clutch control device that is set to match a target slip speed according to the state of the vehicle and controls the lockup clutch based on the hydraulic pressure command value,
Feedback term setting means for setting a feedback term of the hydraulic pressure command value including at least a proportional term and an integral term by using at least a difference between the target slip speed and the actual rotational speed difference, a proportional term gain and an integral term gain. With
At least the integral term gain is changed in accordance with the actual rotational speed difference.

This lock-up clutch control device controls a lock-up clutch that constitutes a starting device together with a pump impeller connected to a prime mover of a vehicle and a turbine runner connected to an input shaft of a transmission. The control device sets a feedback term of a hydraulic pressure command value including at least a proportional term and an integral term by using at least the difference between the target slip speed and the actual rotational speed difference, the proportional term gain, and the integral term gain. A feedback term setting means is provided, and slip control is executed to match the actual rotational speed difference between the prime mover and the input shaft of the transmission with the target slip speed using a hydraulic pressure command value including the feedback term.

The present inventors have intensively studied to enable slip control to be executed stably and responsively under various situations by using such a control device, and input shafts of the prime mover and the transmission when the slip control is executed. We paid attention to the actual rotational speed difference. As a result of research, the present inventors have found that the amount of change in the hydraulic command value required to change the actual rotational speed difference by a certain amount varies according to the actual rotational speed difference itself, and at least feedback The lockup clutch control device is configured to change the integral term gain in the term according to the actual rotational speed difference. Thus, when the actual rotational speed difference between the prime mover and the input shaft of the transmission changes with the execution of the slip control, at least the integral term gain is set to a value according to the actual rotational speed difference, thereby obtaining a desired value. The hydraulic pressure command value can be set more appropriately so that the actual rotational speed difference can be obtained. Therefore, according to this control device, it is possible to execute slip control stably and with high responsiveness under various situations. The “vehicle state” may include the state of the prime mover.

Further, the control device may set at least the integral term gain to a larger value as the actual rotational speed difference is smaller. That is, the smaller the actual rotational speed difference between the prime mover and the input shaft of the transmission is, the smaller the friction coefficient of the friction material becomes, so that the friction force of the lockup clutch when the hydraulic pressure command value changes by a certain amount, that is, the torque capacity The amount of change becomes smaller, and accordingly, the amount of change in the actual rotational speed difference when the hydraulic pressure command value changes by a certain amount also becomes smaller. Therefore, in order to change the actual rotational speed difference by a certain amount by the slip control, it is necessary to increase the change amount of the hydraulic pressure command value as the actual rotational speed difference when the slip control is executed is smaller. Thus, if at least the integral term gain is set to a larger value as the actual rotational speed difference is smaller (a smaller value as the actual rotational speed difference is smaller), the response delay of the lockup clutch is reduced when the actual rotational speed difference is relatively small. In addition to improvement, when the actual rotational speed difference is relatively large, it is possible to suppress the sudden engagement of the lockup clutch and improve the stability of the slip control.

Further, the control device may change each of the integral term gain and the proportional term gain according to the actual rotational speed difference. As described above, by independently setting the proportional term gain and the integral term gain according to the actual rotational speed difference, even if the rotational speed of the input shaft of the transmission fluctuates during the execution of the slip control, the desired gain is obtained. The hydraulic pressure command value can be set more appropriately so that the actual rotational speed difference can be obtained, and the actual rotational speed difference between the prime mover and the input shaft can be quickly converged to the target slip speed.

Further, the pump impeller and the turbine runner may constitute a torque converter together with a stator that rectifies the flow of hydraulic oil from the turbine runner to the pump impeller.

A control method for a lockup clutch according to the present invention includes a pump impeller coupled to a prime mover of a vehicle and a turbine runner coupled to an input shaft of a transmission. In the lockup clutch control method, wherein the actual rotational speed difference with the input shaft is set to coincide with the target slip speed according to the state of the vehicle, and the lockup clutch is controlled based on the hydraulic pressure command value.
(A) obtaining the actual rotational speed difference;
(B) changing at least the integral term gain in the feedback term of the hydraulic pressure command value according to the actual rotational speed difference acquired in step (a);
(C) Using at least the difference between the target slip speed and the actual rotational speed difference, the proportional term gain and the integral term gain, a feedback term of the hydraulic pressure command value including at least a proportional term and an integral term is set. And steps to
Is included.

According to this method, when the actual rotational speed difference between the prime mover and the input shaft of the transmission changes as the slip control is executed, at least the integral term gain is set to a value corresponding to the actual rotational speed difference. Since the hydraulic pressure command value can be set more appropriately so that a desired actual rotational speed difference can be obtained, slip control can be executed stably and responsively under various circumstances.

Further, in step (b), each of the proportional term gain and the integral term gain may be set to a larger value as the actual rotational speed difference is smaller. Furthermore, step (b) may change each of the integral term gain and the proportional term gain in accordance with the actual rotational speed difference. The pump impeller and the turbine runner may constitute a torque converter together with a stator that rectifies the flow of hydraulic oil from the turbine runner to the pump impeller.

It is a schematic block diagram of the motor vehicle 10 which is a vehicle containing the control apparatus of the lockup clutch by this invention. 1 is a schematic configuration diagram of a power transmission device 20 including a lock-up clutch 28. FIG. It is a control block diagram which shows the setting procedure of the hydraulic pressure command value Up by the lockup control module 211 of the speed change ECU 21 as a control device for the lockup clutch. FIG. 6 is an explanatory diagram illustrating the relationship between the input rotation speed Nin of the automatic transmission 30 and the proportional term gain Kp and integral term gain Ki. It is explanatory drawing which illustrates the relationship between the oil temperature Toil, the proportional term gain Kp, and the integral term gain Ki. 6 is an explanatory diagram illustrating the relationship between an actual slip speed u between the engine 12 and the input shaft 31 of the automatic transmission 30, and a proportional term gain Kp and an integral term gain Ki. FIG. 5 is a flowchart showing an example of a slip control routine executed by a lockup control module 211. It is explanatory drawing which illustrates the gain setting map for proportional terms, and the gain setting map for integral terms.

Next, an embodiment for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an automobile 10 which is a vehicle including a lockup clutch control device according to the present invention. An automobile 10 shown in the figure includes an engine (internal combustion engine) 12 as a prime mover that outputs power by explosion combustion of a mixture of hydrocarbon fuel such as gasoline and light oil and air, and an engine electronic for controlling the engine 12. A control unit (hereinafter referred to as “engine ECU”) 14, a brake electronic control unit (hereinafter referred to as “brake ECU”) 16 for controlling an electronically controlled hydraulic brake unit (not shown) 16, connected to the engine 12 and from the engine 12 Including a power transmission device 20 that transmits the motive power to the left and right drive wheels DW. The power transmission device 20 includes a transmission case 22, a starting device 23, a stepped automatic transmission 30, a hydraulic control device 50, a shift electronic control unit (hereinafter referred to as a “shift ECU”) 21 that controls these, and the like. Have.

The engine ECU 14 is configured as a microcomputer centering on a CPU (not shown). In addition to the CPU, a ROM that stores various programs, a RAM that temporarily stores data, an input / output port, and a communication port (all not shown). Etc.). As shown in FIG. 1, the engine ECU 14 includes an accelerator opening Acc from an accelerator pedal position sensor 92 that detects a depression amount (operation amount) of an accelerator pedal 91, a vehicle speed V from a vehicle speed sensor 99, a crankshaft 15 (see FIG. 1). 2), signals from various sensors such as a crankshaft position sensor (not shown) and the like, signals from the brake ECU 16 and the shift ECU 21, and the like are input to the engine ECU 14 based on these signals. The throttle valve 13, a fuel injection valve (not shown), a spark plug and the like are controlled. Further, the engine ECU 14 calculates the rotational speed (rotational speed) Ne of the engine 12 based on the rotational position of the crankshaft 15 detected by the crankshaft position sensor. Further, the engine ECU 14 outputs from the engine 12 based on, for example, the rotational speed Ne, the intake air amount of the engine 12 detected by an air flow meter (not shown), the throttle opening THR of the throttle valve 13, a predetermined map or a calculation formula. An engine torque Te that is an estimated value of the torque that is being calculated is calculated.

The brake ECU 16 is also configured as a microcomputer centering on a CPU (not shown). In addition to the CPU, a ROM for storing various programs, a RAM for temporarily storing data, an input / output port and a communication port (none of which are shown). ) Etc. As shown in FIG. 1, the brake ECU 16 has a master cylinder pressure detected by the master cylinder pressure sensor 94 when the brake pedal 93 is depressed, a vehicle speed V from the vehicle speed sensor 99, signals from various sensors (not shown), and the like. Signals from the engine ECU 14 and the shift ECU 21 are input, and the brake ECU 16 controls a brake actuator (hydraulic actuator) (not shown) and the like based on these signals.

The shift ECU 21 that controls the power transmission device 20 is also configured as a microcomputer centered on a CPU (not shown). In addition to the CPU, a ROM that stores various programs, a RAM that temporarily stores data, an input / output port, and communication Port (none shown) etc. are provided. As shown in FIG. 1, the shift ECU 21 includes a shift lever for selecting a desired shift range from among an accelerator opening Acc from an accelerator pedal position sensor 92, a vehicle speed V from a vehicle speed sensor 99, and a plurality of shift ranges. The shift range SR from the shift range sensor 96 that detects the operation position 95, the oil temperature sensor 55 that detects the oil temperature Toil of the hydraulic oil in the hydraulic control device 50, and the input rotational speed of the automatic transmission 30 (turbine runner 25 or automatic Signals from various sensors such as a rotational speed sensor 33 (see FIG. 2) for detecting the rotational speed (rotational speed) Nin of the input shaft 31 of the transmission 30, the rotational speed (rotational speed) Ne of the engine 12 and the engine torque Te Etc., a signal from the engine ECU 14 and a signal from the brake ECU 16 are input. Starting device based on the signal 23 and the automatic transmission 30, i.e. for controlling the hydraulic control unit 50.

As shown in FIG. 2, the starting device 23 included in the power transmission device 20 includes a pump impeller 24 as an input side fluid transmission element connected to the crankshaft 15 of the engine 12 via a front cover 18 as an input member. The turbine runner 25 serving as an output-side fluid transmission element fixed to the input shaft 31 of the automatic transmission 30 via the turbine hub, the pump impeller 24, and the turbine runner 25 are disposed inside the turbine runner 25 to the pump impeller 24. A stator 26 that rectifies the flow of the hydraulic oil, a one-way clutch 26c that restricts the rotation direction of the stator 26 to one direction, a damper mechanism 27 coupled to the turbine hub, a lock-up clutch 28 as a hydraulic start clutch, and the like.

The pump impeller 24, the turbine runner 25, and the stator 26 constitute a torque converter. When the rotational speed difference between the pump impeller 24 and the turbine runner 25 is large, the function of the stator 26 functions as a torque amplifier, and the rotational speeds of the two. When the difference is small, it functions as a fluid coupling. However, in the starting device 23, the stator 26 and the one-way clutch 26c may be omitted, and the pump impeller 24 and the turbine runner 25 may function as a fluid coupling. Further, the damper mechanism 27 includes, for example, an input element coupled to the lockup clutch 28, an intermediate element coupled to the input element via the plurality of first elastic bodies, and an intermediate element coupled to the plurality of second elastic bodies. And an output element fixed to the turbine hub. The damper mechanism 27 attenuates vibration between the front cover 18 and the turbine hub (input shaft 31) when the lock-up clutch 28 is engaged.

The lock-up clutch 28 mechanically connects (via a damper mechanism 27) the pump impeller 24 and the turbine runner 25, that is, the engine 12 (front cover 18) and the input shaft 31 of the automatic transmission 30 fixed to the turbine hub. The lockup to be connected and the release of the lockup are selectively executed. In this embodiment, the lock-up clutch 28 is configured as a hydraulic multi-plate friction clutch, and includes a lock-up piston 280 supported by the front cover 18 so as to be movable in the axial direction, a plurality of friction engagement plates 281, And an annular flange member (oil chamber defining member) 285.

The plurality of friction engagement plates 281 are fitted to a mating plate fitted to a clutch hub fixed to the front cover 18, and a clutch drum having a friction material and connected to an input element of the damper mechanism 27. A friction plate. The flange member 285 is fixed to the front cover 18 so as to be positioned closer to the damper mechanism 27 than the lockup piston 280, and defines an engagement side oil chamber 28a together with the lockup piston 280. The lock-up clutch 28 is engaged by moving the lock-up piston 280 toward the front cover 18 so as to increase the hydraulic pressure in the engagement-side oil chamber 28a and press the plurality of friction engagement plates. The lockup clutch 28 may be configured as a hydraulic single-plate friction clutch including a lockup piston to which a friction material is attached.

The automatic transmission 30 is capable of transmitting the power transmitted to the input shaft 31 to an output shaft (not shown) while changing the gear stage to a plurality of stages, and includes a plurality of planetary gear mechanisms and from the input shaft 31 to the output shaft. Including a plurality of clutches, brakes, one-way clutches, and the like for changing the power transmission path. The output shaft of the automatic transmission 30 is connected to the drive wheels DW via a gear mechanism and a differential mechanism (not shown). Further, the plurality of clutches and brakes are engaged / disengaged by the hydraulic pressure from the hydraulic control device 50. The automatic transmission 30 may be configured as a so-called continuously variable transmission.

The hydraulic control device 50 regulates hydraulic oil from an oil pump (not shown) driven by power from the engine 12 to generate the line pressure PL in order to generate hydraulic pressure to the starting device 23 and the automatic transmission 30. A primary regulator valve, for example, a secondary regulator valve that regulates the drain pressure of the primary regulator valve to generate the secondary pressure Psec, a modulator valve that regulates the line pressure PL to generate a constant modulator pressure Pmod, for example, the accelerator pressure Pmod A linear solenoid valve that adjusts the pressure according to the opening degree Acc or the opening degree THR of the throttle valve 13 to generate a signal pressure to the primary regulator valve. The hydraulic oil is supplied to the plurality of automatic transmissions 30 according to the operation position of the shift lever 95. For clutch and brake Feeding possible to manual valve, including each manual hydraulic oil from the valve (line pressure PL) can be output to the corresponding clutch or brake by regulating a plurality of linear solenoid valves, etc. (all not shown).

Further, the hydraulic control device 50 adjusts, for example, the modulator pressure Pmod according to the applied current value to generate a lockup solenoid pressure Pslu, and a lockup solenoid valve SLU and a lockup solenoid valve SLU. The lockup solenoid valve Pslu operates as a signal pressure, and the secondary pressure Psec is adjusted to generate the lockup pressure Plup to the lockup clutch 28, and the lockup from the lockup solenoid valve SLU. A lock-up relay valve that operates using the solenoid pressure Pslu as a signal pressure and permits / regulates the supply of the lock-up pressure Plup from the lock-up control valve 51 to the engagement-side oil chamber 28a of the lock-up clutch 28. And a 52.

In this embodiment, the lockup solenoid valve SLU sets the lockup solenoid pressure Pslu to a value of 0 when the applied current value is relatively small (does not generate the lockup solenoid pressure Pslu), and the applied current value. After that, the lock-up solenoid pressure Pslu is set higher as the current value increases. Further, when the lockup solenoid pressure Pslu is generated by the lockup solenoid valve SLU, the lockup control valve 51 reduces the secondary pressure Psec, which is the original pressure, as the lockup solenoid pressure Pslu is lower, thereby reducing the lockup pressure Plup. When the lockup solenoid pressure Pslu is set lower than the predetermined lockup engagement pressure P1, the secondary pressure Psec is output as it is as the lockup pressure Plup. Further, the lockup relay valve 52 supplies the circulating pressure Pcir adjusted to a pressure lower than the secondary pressure Psec to the fluid transmission chamber 23a of the starting device 23 when the lockup solenoid pressure Pslu is not supplied from the lockup solenoid valve SLU. In addition, when the lockup solenoid pressure Pslu is supplied from the lockup solenoid valve SLU, the circulation pressure Pcir is supplied to the fluid transmission chamber 23a and the engagement side oil chamber 28a of the lockup clutch 28 is supplied from the lockup control valve 51. The lockup pressure Plup is supplied.

As a result, when the lockup solenoid pressure Pslu is not generated by the lockup solenoid valve SLU, the hydraulic oil (lubricating pressure Pcir) is supplied from the lockup relay valve 52 into the fluid transmission chamber 23a, and the lockup piston 280 and the front cover are supplied. The hydraulic fluid flows into the oil passage formed between the hydraulic fluid 18 and the hydraulic fluid (lock-up pressure Plup) is not supplied into the engagement-side oil chamber 28a. It is released without executing. On the other hand, when the lock-up solenoid pressure Pslu generated by the lock-up solenoid valve SLU is supplied to the lock-up control valve 51 and the lock-up relay valve 52, hydraulic oil, that is, lubrication from the lock-up relay valve 52 into the fluid transmission chamber 23a. While the pressure Pcir is supplied, the lockup pressure Plup generated by the lockup control valve 51 is supplied from the lockup relay valve 52 to the engagement side oil chamber 28a of the lockup clutch 28. Therefore, when the lockup pressure Plup becomes higher than the lubrication pressure Pcir, the lockup piston 280 moves toward the front cover 18, the lockup solenoid pressure Pslu becomes equal to or higher than the lockup engagement pressure P1, and the lockup pressure Plup is increased. When the secondary pressure Psec is reached, the lockup clutch 28 is completely engaged and the lockup is completed.

The plurality of linear solenoid valves, the lock-up solenoid valve SLU, other solenoid valves (not shown) (not shown) and the like included in the hydraulic control device 50 described above are controlled by the transmission ECU 21. As shown in FIG. 2, the shift ECU 21 includes a shift control module 210 and a lockup control module 211 in cooperation with hardware such as a CPU, ROM, and RAM, and software such as a control program installed in the ROM. Is constructed as a functional block.

The shift control module 210 obtains a target shift stage corresponding to the accelerator opening Acc (or the throttle opening 13 of the throttle valve 13) and the vehicle speed V from a predetermined shift diagram (not shown), and from the current shift stage to the target shift stage. Corresponding to the engagement pressure command value to the linear solenoid valve corresponding to the clutch or brake engaged with the change to the gear and the clutch or brake released with the change from the current gear to the target gear Set the release pressure command value to the linear solenoid valve. Further, the shift control module 210 sets a holding pressure command value to the linear solenoid valve corresponding to the engaged clutch or brake during the change from the current shift speed to the target shift speed or after the formation of the target shift speed. .

The lockup control module 211 sets a hydraulic pressure command value Up for the lockup solenoid valve SLU described above. The lock-up control module 211 sets a hydraulic pressure command value Up so that lock-up is executed by the lock-up clutch 28 when a predetermined lock-up condition is satisfied, and a lock-up solenoid from an auxiliary battery (not shown) is set. A drive circuit (not shown) is controlled so that a current corresponding to the hydraulic pressure command value Up is applied to the solenoid portion of the valve SLU. In addition, when a predetermined slip control execution condition is satisfied, the lockup control module 211 is configured so that the front cover 18 (engine 12) as an input member and the input shaft 31 of the automatic transmission 30 are engaged by half-engagement of the lockup clutch 28. The slip control is executed so that the rotational speed difference ΔN (slip speed) matches the target slip speed u * corresponding to at least one of the states of the automobile 10 and the engine 12 (vehicle state). By executing such slip control at the time of lock-up clutch 28 lock-up (when starting), the torque capacity of the lock-up clutch 28 is gradually increased to generate vibrations due to torque fluctuations associated with lock-up. It can suppress well. In addition, the slip control is executed so as to cause the lockup clutch 28 to slip during acceleration or deceleration of the automobile 10 or during a shift, etc., so that the occurrence of vibration due to torque fluctuation accompanying the lockup is improved. While suppressing, it is possible to improve the power transmission efficiency and the fuel consumption of the engine 12 as compared with the case where lockup is not performed.

Next, the slip control of the lockup clutch 28 in the automobile 10 will be described.

FIG. 3 is a control block diagram showing a procedure for setting the hydraulic pressure command value Up by the lockup control module 211 of the transmission ECU 21. As shown in the figure, when executing the slip control, the lockup control module 211 sets the feedforward term FF of the hydraulic pressure command value Up based on, for example, the engine torque Te, the input rotational speed Nin, and the target slip speed u *. . The lockup control module 211 also detects the target slip speed u * and the actual slip speed that is the actual rotational speed difference (actual rotational speed difference) between the engine 12 (front cover 18) and the input shaft 31 of the automatic transmission 30. Using the difference (u * −u) from u (= Ne−Nin), the proportional term gain Kp and the integral term gain Ki, the feedback term FB of the hydraulic pressure command value Up including the proportional term FBp and the integral term FBi is obtained. Set. Note that the feedback term FB of the hydraulic pressure command value UP may further include a differential term in addition to the proportional term FBp and the integral term FBi. Then, the lockup control module 211 sets the hydraulic pressure command value Up by adding the feedforward term FF and the feedback term FB. Thus, in this embodiment, the transmission ECU 21 (lockup control module 211) uses the hydraulic command value Up including the feedback term FB set by relatively simple PI control (or PID control) and the engine 12 to Slip control is executed to match the actual slip speed u with the input shaft 31 of the automatic transmission 30 to the target slip speed u *. As a result, it is possible to significantly reduce the computation load associated with the execution of slip control.

Here, the present inventors have intensively studied to enable slip control to be executed stably and responsively in a wider execution range and various vehicle conditions by the above-described speed change ECU 21 (lockup control module 211). In response to the torque (power) transmitted from the engine 12 to the front cover 18 when slip control is executed, the input rotational speed Nin from the input shaft 31 (turbine runner 25) side or the rotational speed Ne of the engine 12 is determined. We paid attention to the reaction torque acting. That is, when the slip control is executed in the starting device 23 including the lockup clutch 28 and the torque converter having the pump impeller 24, the turbine runner 25, and the stator 26, the speed ratio between the pump impeller 24 and the turbine runner 25 is determined. Tc = C _T · ω _i from the input shaft 31, that is, the turbine runner 25 side of the torque converter, when the capacity coefficient of the torque converter corresponding to is set to “C _T ” and the rotational angular velocity of the input shaft 31 is set to “ω _i ”. A reaction torque of ² acts on the pump impeller 24 as a reaction force against the torque from the engine 12. When the coefficient according to the capacity coefficient C _T is “C _E ” and the rotational angular velocity of the engine 12 (crankshaft 15) is “ω _e ”, the reaction torque Tc is expressed as Tc = C _E · ω _e. ² can be expressed.

Similarly, when slip control is executed in a starting device that includes a lock-up clutch as a hydraulic start clutch and a fluid coupling (without a stator) having a pump impeller and a turbine runner, From the turbine runner side, that is, the input shaft side of the transmission, torque (reaction torque) having a value approximately proportional to the square value of the input shaft and the rotational angular velocity of the engine acts on the pump impeller as a reaction force against the torque from the engine. Even when the lockup clutch is combined only with the damper mechanism or used alone (when not combined with a fluid transmission device such as a torque converter), the slip control is performed from the input shaft side of the transmission. Torque (reaction torque) having a value approximately proportional to the square value of the rotational angular velocity of the input shaft or the engine acts on an input member connected to the engine (crankshaft) as a reaction force against the torque from the engine.

Then, as a result of research, the present inventors responded to fluctuations in the reaction torque Tc acting on the torque from the engine 12 from the input shaft 31 side, that is, fluctuations in the input rotational speed Nin and the rotational speed Ne of the engine 12. Thus, it has been found that the amount of change in the hydraulic command value Up required to change the actual slip speed u by a certain amount varies. That is, when the actual slip speed u is kept constant by the slip control, Te = −T _LU −Tc between the torque capacity T _{LU of the} lockup clutch, the torque Te of the engine 12 and the reaction torque Tc. The relationship is established. Further, the reaction force torque Tc acting on the torque from the engine 12 from the input shaft 31 side is approximately proportional to the square value of the rotational angular velocity ω _i of the input shaft 31 or the engine 12 as described above. The higher the rotational speed of the engine 12, the larger the engine 12 becomes. Therefore, the higher the rotational speed of the input shaft 31 and the engine 12, the larger the amount of change in the torque capacity _TLU of the lockup clutch 28 required to change the actual slip speed u by a certain amount by the slip control. For this reason, in order to change the actual slip speed u by a certain amount by the slip control, it is necessary to increase the change amount of the hydraulic pressure command value Up as the input rotational speed Nin when the slip control is executed is higher. .

Based on this, in this embodiment, the lockup control module 211 of the speed change ECU 21 is configured to change the proportional term gain Kp and the integral term gain Ki in the feedback term FB according to the input rotational speed Nin. It was. Specifically, as shown in FIG. 4, the lockup control module 211 is configured to set each of the proportional term gain Kp and the integral term gain Ki to a larger value as the input rotational speed Nin is higher. The As a result, when the input rotational speed Nin is relatively low, sudden engagement of the lockup clutch 28 is suppressed to improve the stability of the slip control, and when the input rotational speed Nin is relatively high, the lock is increased. It is possible to improve the responsiveness of the up clutch 28 to the hydraulic pressure command value Up.

In addition, in the course of the above-described research, the present inventors have also paid attention to the oil temperature Toil of the hydraulic oil that operates the lock-up clutch 28 when the slip control is performed. Then, the present inventors have found that the amount of change in the hydraulic pressure command value Up required to change the actual slip speed u by a certain amount varies according to the variation in the oil temperature Toil. That is, the higher the oil temperature Toil of the hydraulic oil, the smaller the friction coefficient (dynamic friction coefficient) of the friction material of the lockup clutch 28 due to the lower viscosity of the hydraulic oil. Therefore, the higher the oil temperature Toil of the operating oil, oil pressure command value Up frictional force or the amount of change in the torque capacity T _LU of the lock-up clutch 28 is reduced when the change by a predetermined amount, the hydraulic pressure command value with it The amount of change in the actual slip speed u when Up changes by a certain amount is also reduced. Therefore, in order to change the actual slip speed u by a certain amount by the slip control, it is necessary to increase the change amount of the hydraulic pressure command value Up as the oil temperature Toil when the slip control is executed is higher.

Based on this, in the present embodiment, the lockup control module 211 of the transmission ECU 21 is changed so that the proportional term gain Kp and the integral term gain Ki in the feedback term FB are further changed according to the oil temperature Toil of the hydraulic oil. It was decided to compose. Specifically, as shown in FIG. 5, the lockup control module 211 is configured to set each of the proportional term gain Kp and the integral term gain Ki to a larger value as the oil temperature Toil is higher. . Thus, when the oil temperature Toil is relatively low, slippage is suppressed by suppressing the sudden engagement of the lockup clutch 28 due to the increase in the friction coefficient (dynamic friction coefficient) in the lockup clutch 28 due to the increase in the viscosity of the hydraulic oil. In addition to improving the stability of the control, it is possible to improve the responsiveness of the lockup clutch 28 to the hydraulic pressure command value Up when the oil temperature Toil is relatively high.

Furthermore, the present inventors pay attention to the actual slip speed (actual rotational speed difference) u between the engine 12 and the input shaft 31 of the automatic transmission 30 when the slip control is executed in the course of the above-described research. did. The inventors have found that the amount of change in the hydraulic command value Up required to change the actual slip speed u by a certain amount varies depending on the actual slip speed u itself. That is, the smaller the actual slip speed u between the engine 12 and the input shaft 31 of the automatic transmission 30 is, the smaller the friction coefficient (dynamic friction coefficient) of the friction material of the lockup clutch 28 is. For this reason, the smaller the actual slip speed u, the smaller the frictional force of the lockup clutch 28, that is, the amount of change in the torque capacity _TLU when the oil pressure command value Up changes by a certain amount. The amount of change in the actual slip speed u when it changes by a certain amount also becomes small. Therefore, in order to change the actual slip speed u by a certain amount by the slip control, it is necessary to increase the change amount of the hydraulic pressure command value Up as the actual slip speed u when the slip control is executed is smaller.

Based on this, in the present embodiment, the proportional ECU gain Kp and the integral term gain Ki in the feedback term FB are further changed according to the actual slip speed u between the engine 12 and the input shaft 31. The lockup control module 211 is configured. Specifically, as shown in FIG. 6, the lockup control module 211 is configured to set each of the proportional term gain Kp and the integral term gain Ki to a larger value as the actual slip speed u is smaller. The As a result, when the actual slip speed u is relatively low, the response delay of the lockup clutch 28 due to a decrease in the friction coefficient (dynamic friction coefficient) in the lockup clutch 28 is improved and the actual slip speed u is relatively low. If it is larger, it is possible to suppress the sudden engagement of the lockup clutch 28 and improve the stability of the slip control.

FIG. 7 is a flowchart showing an example of a slip control routine executed by the lockup control module 211.

The slip control routine shown in the figure is repeatedly executed at predetermined intervals by the lockup control module 211 when slipping occurs in the lockup clutch 28 in accordance with the establishment of the slip control execution condition. At the start of the slip control routine of FIG. 7, the lockup control module 211 (CPU) detects the accelerator opening Acc from the accelerator pedal position sensor 92, the engine torque Te from the engine ECU 14, the rotational speed Ne of the engine 12, and the rotational speed sensor. Input processing of data necessary for control, such as the input rotational speed Nin from 33 and the oil temperature Toil from the oil temperature sensor 55 (temperature of hydraulic oil to the lockup clutch 28), is executed (step S100).

After the input process in step S100, the lockup control module 211 sets a target slip speed u * corresponding to the accelerator opening Acc and the engine speed Ne (vehicle state) input in step S100 (step S110). ). In the present embodiment, for example, the relationship between the accelerator opening Acc and the engine speed Ne and the target slip speed u * is determined in advance and stored in the ROM of the speed change ECU 21 as a target slip speed setting map (not shown). In step S110, the target slip speed u * corresponding to the given accelerator opening Acc and the rotational speed Ne is derived and set from the target slip speed setting map. The target slip speed u * may be set based on the opening degree THR and the rotational speed Ne of the throttle valve 13, and is set based on other parameters in addition to the accelerator opening degree Acc and the rotational speed Ne. Alternatively, it may be set based on parameters other than the accelerator opening Acc and the rotational speed Ne.

After setting the target slip speed u * in step S110, the lockup control module 211 sets the feedforward term FF of the hydraulic pressure command value Up based on, for example, the engine torque Te, the input rotational speed Nin, and the target slip speed u *. (Step S120). In the present embodiment, for example, the relationship between the engine torque Te, the input rotational speed Nin, the target slip speed u *, and the value of the feedforward term FF is determined in advance and stored in the ROM of the transmission ECU 21 as a feedforward term setting map (not shown). ing. In step S120, the value of the feedforward term FF corresponding to the applied engine torque Te, the input rotation speed Nin, and the target slip speed u * is derived from the feedforward term setting map. The feedforward term FF may be set based on other parameters in addition to the engine torque Te, the input rotational speed Nin, and the target slip speed u *, and the engine torque Te, the input rotational speed Nin, and the target slip speed. It may be set based on parameters other than u *. Further, the lockup control module 211 calculates the actual slip speed u by subtracting the input rotational speed Nin from the rotational speed Ne of the engine 12 input in step S100 (step S130).

Next, the lockup control module 211 determines the proportional term gain Kp in the feedback term FB and the integral term based on the input rotational speed Nin and the oil temperature Toil inputted in step S100 and the actual slip speed u calculated in step S130. A gain Ki is set (step S140). In the present embodiment, the relationship between the input rotation speed Nin, the oil temperature Toil, the actual slip speed u, and the proportional term gain Kp is determined in advance and stored in the ROM of the transmission ECU 21 as a proportional term gain setting map. Further, the relationship among the input rotational speed Nin, the oil temperature Toil, the actual slip speed u, and the integral term gain Ki is determined in advance and stored in the ROM of the transmission ECU 21 as an integral term gain setting map. In step S140, values corresponding to the given input rotational speed Nin, oil temperature Toil, and actual slip speed u are derived from the proportional term gain setting map and set as the proportional term gain Kp. Values corresponding to the rotational speed Nin, the oil temperature Toil, and the actual slip speed u are derived from the integral term gain setting map and set as the integral term gain Kp.

Figure 8 illustrates the proportional term gain setting map and integral term gain setting map. The proportional term gain setting map shows the relationship between the input rotation speed Nin and the proportional term gain Kp shown in FIG. 4, the relationship between the oil temperature Toil and the proportional term gain Kp shown in FIG. 5, and the relationship shown in FIG. Based on the relationship between the actual slip speed u and the proportional term gain Kp, for example, a plurality of oil temperatures Toil (temperatures T1 and T2 (T2> T1 in the example of FIG. 8), for example, T1 = 60 to 80 °, T2 = 100 to 120 °) and a plurality of actual slip speeds u (in the example of FIG. 8, actual slip speeds u1, u2 and u3 (u1 <u2 <u3), for example, u1 = 10 to 30 rpm) , U2 = 40 to 60 rpm, u3 = 80 to 100 rpm) and the relationship between the input rotational speed Nin and the proportional term gain Kp. In other words, in the present embodiment, the proportional term gain setting map indicates that the proportional term gain Kp is larger (smaller) as the input rotational speed Nin is higher (lower) and the proportional temperature gain is higher (lower) as the oil temperature Toil is higher. The gain Kp is made larger (smaller) and the proportional term gain Kp is made larger (smaller) as the actual slip speed u is smaller (higher).

Further, the integral term gain setting map shows the relationship between the input rotational speed Nin and the integral term gain Ki shown in FIG. 4, the relationship between the oil temperature Toil and the integral term gain Ki shown in FIG. 5, and FIG. For example, for each of a plurality of oil temperatures Toil (temperatures T1 and T2 in the example of FIG. 8) and a plurality of actual slip speeds u ( In the example of FIG. 8, it is created by defining the relationship between the input rotational speed Nin and the integral term gain Ki for each of the actual slip speeds u1, u2 and u3). That is, in the present embodiment, the integral term gain setting map indicates that the integral term gain Ki is larger (smaller) as the input rotational speed Nin is higher (lower), and the integral term gain Ki is higher (lower) as the oil temperature Toil is higher. The gain Ki is made larger (smaller) as the gain Ki is larger (smaller) and the actual slip speed u is smaller (higher).

Note that the proportional term gain setting map and the integral term gain setting map as shown in FIG. 8 are used, and the oil temperature Toil and the actual slip speed u input in step S100 are the temperatures T1 in FIG. , T2, and the actual slip speeds u1 to u3, in step S140, the proportional term gain is obtained by linearly interpolating a plurality of values derived from the proportional term gain setting map and the integral term gain setting map. Kp and integral term gain Ki are set. It goes without saying that the proportional term gain setting map and the integral term gain setting map can be created at intervals smaller than the intervals of the oil temperature Toil and the actual slip speed u shown in FIG.

After setting the proportional term gain Kp and the integral term gain Ki in step S140, the proportional term is used for the difference (u * -u) between the target slip speed u * and the actual slip speed u (= Ne−Nin). A value obtained by multiplying the gain Kp is set as the proportional term FBp of the feedback term FB, and an integrated value obtained by multiplying the difference (u * −u) by the integral term gain Ki is set as the integral term FBp of the feedback term FB. (Step S150). Further, the lockup control module 211 sets the value obtained by adding the proportional term FBp and the integral term Fbi set in step S140 to the feedforward term FF set in step S120, that is, the feedback term FB, as the hydraulic pressure command value Up. (Step S160). Then, the lockup control module 211 controls a drive circuit (not shown) that sets a current to the solenoid portion of the lockup solenoid valve SLU based on the hydraulic pressure command value Up (step S170). Thereafter, when the next execution timing of this routine arrives, the lockup control module 211 executes the processing after step S100 again.

As described above, the shift ECU 21 (lockup control module 211), which is the control device for the lockup clutch 28 constituting the starting device 23, has at least the target slip speed u * and the actual slip speed (actual rotation speed difference) u. The feedback term FB of the hydraulic pressure command value Up including at least the proportional term FBp and the integral term FBi is set using the difference (u * −u), the proportional term gain Kp, and the integral term gain Ki (see FIG. 7). Step S150), slip using the hydraulic command value Up including the feedback term FB to match the actual slip speed u, which is the actual rotational speed difference between the engine 12 and the input shaft 31 of the automatic transmission 30, with the target slip speed u *. Control is executed (steps S160 and S170 in FIG. 7). The shift ECU 21 calculates the actual slip speed u when executing the slip control (step S130 in FIG. 7), and sets the proportional term gain Kp and the integral term gain Ki based on the actual slip speed u. The proportional term gain Kp and the integral term gain Ki are changed according to the fluctuation of the actual slip speed u (step S140 in FIG. 7). Thus, when the actual slip speed u between the engine 12 and the input shaft 31 of the automatic transmission 30 changes with the execution of the slip control, the proportional term gain Kp and the integral term gain Ki are individually slipped. By setting the value according to the speed u, the hydraulic pressure command value Up can be set more appropriately so that a desired actual slip speed u can be obtained. Therefore, in the starting device 23 including the lock-up clutch 28, it is possible to execute slip control stably and with high responsiveness under various situations.

Further, in the above-described embodiment, each of the proportional term gain Kp and the integral term gain Ki is set to a larger value (a smaller value as the actual slip speed u is smaller) (step S140 in FIG. 7). 6 and 8). Thereby, when the actual slip speed u is relatively small, the response delay of the lockup clutch 28 is further improved, and when the actual slip speed u is relatively large, the sudden engagement of the lockup clutch 28 is suppressed. Thus, the stability of the slip control can be further improved.

Further, the speed change ECU 21 has an input rotational speed Nin, an oil temperature Toil, a proportional term gain setting map that defines the relationship between the actual slip speed u and the proportional term gain Kp, an input rotational speed Nin, an oil temperature Toil, and An integral term gain setting map that defines the relationship between the actual slip speed u and the integral term gain Ki; The speed change ECU 21 derives the proportional term gain Kp corresponding to the input rotational speed Nin, the oil temperature Toil, and the actual slip speed u from the proportional term gain setting map, and the input rotational speed from the integral term gain setting map. An integral term gain Ki corresponding to Nin, oil temperature Toil, and actual slip speed u is derived (step S140 in FIG. 7). As a result, the proportional term gain Kp and the integral term gain Ki can be individually set to more appropriate values according to the input rotational speed Nin, the oil temperature Toil, and the actual slip speed u. Therefore, the hydraulic pressure command value Up can be set extremely appropriately.

Further, as in the above-described embodiment, the proportional term gain Kp and the integral term gain Ki of the feedback term FB of the hydraulic pressure command value Up are individually set according to the input rotational speed Nin, the oil temperature Toil, and the actual slip speed u. Then, the hydraulic pressure command value can be set more appropriately so that a desired actual rotational speed difference can be obtained, and the actual slip speed u can be quickly converged to the target slip speed u *. Further, the proportional term gain Kp and the integral term gain Ki are set using, for example, a three-dimensional map in which the input rotation speed Nin, the oil temperature Toil, and the actual slip speed u are taken on the X axis, the Y axis, and the Z axis. May be. However, instead of individually setting the proportional term gain Kp and the integral term gain Ki according to the input rotational speed Nin or the like, only the integral term gain Ki is set to the input rotational speed Nin, the oil temperature Toil, and the actual slip speed u. You may set according to at least one of these.

In the above embodiment, the lock-up clutch 28 constitutes the starter 23 together with the pump impeller 24 connected to the engine 12 and the turbine runner 25 connected to the input shaft 31 of the automatic transmission 30, and the engine 12 (front The cover 18) and the input shaft 31 are connected and the connection between the two is released, but the application target of the present invention is not limited to this. That is, the present invention may be a hydraulic start clutch that is combined only with a damper mechanism or a hydraulic start clutch that is used alone (not combined with a fluid transmission device such as a torque converter or a fluid coupling). Therefore, the pump impeller 24, the turbine runner 25, the stator 26, and the damper mechanism 27 may be omitted from the above-described starting device 23.

In addition, the correspondence between the main elements in the above embodiment and the main elements of the invention described in the summary section of the invention is the same as the embodiment for carrying out the invention described in the summary section of the invention. Since this is an example for concrete description, the elements of the invention described in the summary section of the invention are not limited. In other words, the embodiments are merely specific examples of the invention described in the Summary of Invention column, and the interpretation of the invention described in the Summary of Invention column should be made based on the description in that column. It is.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention. Absent.

The present invention can be used in the manufacturing industry of a lock-up clutch and a starter having the same.

Claims

A hydraulic impulsive command value to a lock-up clutch constituting a starting device together with a pump impeller coupled to a vehicle prime mover and a turbine runner coupled to an input shaft of a transmission is the difference in actual rotational speed between the prime mover and the input shaft. In a lockup clutch control device that is set to match a target slip speed according to the state of the vehicle and controls the lockup clutch based on the hydraulic pressure command value,
Feedback term setting means for setting a feedback term of the hydraulic pressure command value including at least a proportional term and an integral term by using at least a difference between the target slip speed and the actual rotational speed difference, a proportional term gain and an integral term gain. With
A control device for a lockup clutch, wherein at least the integral term gain is changed according to the actual rotational speed difference.
In the lockup clutch control device according to claim 1,
A control apparatus for a lockup clutch, wherein at least the integral term gain is set to a larger value as the actual rotational speed difference is smaller.
In the lockup clutch control device according to claim 1 or 2,
A control apparatus for a lockup clutch, wherein the integral term gain and the proportional term gain are changed in accordance with the actual rotational speed difference.
In the control apparatus of the lockup clutch as described in any one of Claim 1 to 3,
The pump impeller and the turbine runner constitute a torque converter together with a stator that rectifies the flow of hydraulic oil from the turbine runner to the pump impeller.
A hydraulic impulsive command value to a lock-up clutch constituting a starting device together with a pump impeller coupled to a vehicle prime mover and a turbine runner coupled to an input shaft of a transmission is the difference in actual rotational speed between the prime mover and the input shaft. In a lockup clutch control method, which is set to coincide with a target slip speed according to the state of the vehicle, and controls the lockup clutch based on the hydraulic pressure command value,
(A) obtaining the actual rotational speed difference;
(B) changing at least the integral term gain in the feedback term of the hydraulic pressure command value according to the actual rotational speed difference acquired in step (a);
(C) Using at least the difference between the target slip speed and the actual rotational speed difference, the proportional term gain and the integral term gain, a feedback term of the hydraulic pressure command value including at least a proportional term and an integral term is set. And steps to
Control method for lock-up clutch including
In the control method of the lockup clutch according to claim 5,
In step (b), at least the integral term gain is set to a larger value as the actual rotational speed difference is smaller.
In the control method of the lockup clutch according to claim 5 or 6,
In step (b), the integral term gain and the proportional term gain are each changed in accordance with the actual rotational speed difference.
In the control method of the lockup clutch according to any one of claims 5 to 7,
The lockup clutch control method, wherein the pump impeller and the turbine runner constitute a torque converter together with a stator that rectifies the flow of hydraulic oil from the turbine runner to the pump impeller.