JP3099206B2 - Start control device for fluid coupling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting control device for a fluid coupling provided in a power transmission system having a fluid coupling for intermittently transmitting the rotational force of an engine to a continuously variable transmission, and more particularly to a fluid coupling control means. The present invention relates to a start control device for a fluid coupling that performs a connection / disconnection operation of the fluid coupling according to operation information of the engine.

[0002]

2. Description of the Related Art Hitherto, as a power transmission system connected to an engine of a vehicle, a power transmission system connected with a fluid coupling, a forward / reverse switching unit, a continuously variable transmission unit, a final reduction gear, a differential, and wheels has been known.

[0003] As a fluid coupling, the damper clutch includes a compressor integrally connected to the engine and a turbine connected to and separated from the compressor and connected to the transmission side, and a hydraulic oil supplied from a clutch control valve through a connection hydraulic path. And are separated so as to receive the pressure oil from the disconnect hydraulic path. Conventionally, the damper clutch performs the switching according to the pilot pressure from the electromagnetic control valve, and the electromagnetic control valve is driven according to the control output of the clutch control means. In this case, the clutch control unit is operated to connect or disconnect according to the engine operation information, particularly, the gear position information.

On the other hand, the continuously variable transmission supplies a gear ratio control oil pressure based on a gear ratio determined according to the operation information of the engine to a gear ratio control valve, and the two pulley control oil pressures regulated by the valve are used as primary and secondary pulley control oil pressures. The hydraulic pressure is supplied to both secondary hydraulic actuators, thereby changing the winding diameter ratio of the belt wound around the pair of pulleys, thereby performing a continuously variable transmission. Here, when the same hydraulic pressure is supplied to both hydraulic actuators, the winding diameter ratio of the primary pulley is set to be larger than that of the secondary pulley,
A low gear ratio (high gear) is achieved, and conversely, a high gear ratio (low gear) is achieved as the hydraulic pressure on the primary cylinder side is reduced.

[0005] Further, a forward / reverse switching unit provided in the continuously variable transmission is supplied with hydraulic fluid for switching between forward and reverse from a manual valve for switching the speed, to a hydraulic actuator for forward / reverse switching of the switching unit. The actuator is configured to switch between forward and reverse.

In such a power transmission system, a target engine speed Neo is normally set according to the throttle opening as shown in an M3 map in FIG.
, the continuously variable transmission works and the high gear ratio (low gear) L
The continuously variable transmission is continuously performed from the side to the lower speed ratio (higher speed) OD side, and the vehicle speed V is increased.

[0007]

However, when the clutch control means sets the target engine speed Neo according to the throttle opening when the vehicle is started by such a device, the engine speed becomes the target engine speed Neo.
After reaching the target engine speed, the damper clutch is disengaged until the target engine speed Neo is reached, and the engine speed is controlled so as to increase the engine speed at an early stage.

For this reason, at the time of starting, the slip state of the damper clutch changes depending on the degree of engine output, the degree of slip between the compressor on the engine side and the turbine side receiving the load on the wheel side, and the like. For this reason, the time-dependent change characteristic of the engine speed when the engine speed increases at the start and approaches the target engine speed Neo differs each time. In particular, when the slip amount is large, only the increase in the engine output speed rapidly advances. For example, as shown by a broken line e1 in FIG. 4, the target value is exceeded. Conversely, when the slip amount is small, the two-dot chain line e2 is shown in FIG. As shown by, the engine speed may drop rapidly. If the engine speed exceeds the target value, the engine output is largely used only to increase the engine speed, and the starting torque decreases. Conversely, if the engine speed drops significantly, the engine stops due to insufficient output. In some cases, the starting characteristics become unstable depending on the degree of slip of the damper clutch, and there is a problem.

An object of the present invention is to provide a starting control device for a fluid coupling which can improve the starting characteristics.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a compressor which rotates integrally with an engine and a hydraulic oil passage which is connected to the compressor by receiving pressure oil from a joint hydraulic passage. Coupling with a fluid coupling provided with a turbine that receives and separates hydraulic oil, a continuously variable transmission that is provided in a power transmission system including the fluid coupling and can continuously achieve a target gear ratio, and joining the fluid coupling A fluid coupling, comprising: a clutch control valve for supplying switching pressure oil to a hydraulic path and a disconnection hydraulic path in accordance with a switching command; and a fluid coupling control means for switching and controlling the clutch control valve according to engine operation information. In the start control device, the fluid coupling control means calculates the required torque from the actual engine speed and the throttle opening of the engine at the time of start, and determines the required torque according to the required torque. The clutch joining oil pressure of the fluid coupling is calculated as a reference joining oil pressure, and a proportional integral term corresponding to a deviation between the actual engine speed and the target engine speed is calculated as a corrected oil pressure by PI control. The joint hydraulic pressure of the fluid coupling, which can eliminate the deviation between the two engine rotational speeds so as to achieve the target engine rotational speed according to the degree, is calculated by adding the correction hydraulic pressure by PI control to the reference joint hydraulic pressure. The clutch control valve is controlled so as to supply the hydraulic pressure to the joining hydraulic path.

[0011]

When the fluid coupling control means starts, the required torque to be transmitted is determined from the actual engine speed of the engine and the throttle opening, and the clutch hydraulic pressure of the fluid coupling according to the required torque is calculated as a reference hydraulic pressure. Calculating a proportional integral term corresponding to a deviation between the actual engine speed and the target engine speed as a corrected hydraulic pressure by PI control, and setting the actual engine speed to a target engine speed corresponding to the throttle opening. The joining hydraulic pressure of the fluid coupling that can eliminate the deviation of both engine speeds is calculated by adding the correction oil pressure by the PI control to the reference joining oil pressure, and the clutch control valve is supplied to supply the joining oil pressure to the joining oil pressure path. By driving the engine, the actual engine speed can be adjusted to the target engine speed. To sudden change the force, it is possible to give a rotational load in accordance with the joining force to the engine side.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The starting control apparatus for a fluid coupling shown in FIG. 1 is provided in a power transmission system of a vehicle. As shown in FIG. 2, the power transmission system includes an engine 1, a fluid coupling 2, a continuously variable transmission 3, a speed reducer 4, a differential 5, left and right axle shafts 6, and drive wheels (not shown). It is configured so that The fluid coupling 2 includes a compressor 8 that rotates integrally with an engine output shaft 7, a turbine 9 that receives the rotational energy of the compressor 8 via oil, and a direct coupling clutch 10 described below. The distal end of the compressor 8 is pivotally supported via a bearing 12 at the base of the casing 14 concentrically with the turbine shaft 11. Here, the tip of the compressor 8 also serves as a drive shaft of the oil pump 13, thereby enabling oil to be supplied to the continuously variable transmission 3 and the fluid coupling 2.

The continuously variable transmission 3 includes a forward / reverse switching unit 15 and a continuously variable transmission unit 16. Here, the forward / reverse switching unit 15
Is a turbine shaft 11 pivotally supported between a pair of bearings 12 and 17.
, A forward clutch 18 and a reverse clutch 19 are provided. The forward clutch 18 is connected to a peripheral portion of a front rotating body 20 ′ integral with the turbine shaft 11 and a carrier 2 of a planetary gear train 21 ′ described later.
The peripheral portion 2 'is brought into contact with and separated from the peripheral portion, and is switched by a hydraulic piston 23' for a forward clutch. Here, the planetary gear train 21 ′ includes a sun gear 24 ′ integrated with the turbine shaft 11, a plurality of planetary gears 25 ′ meshed therearound and pivotally supported by the carrier 22 ′, and inner peripheral teeth meshed with the planetary gears 25 ′. Ring gear 26 '. The reverse clutch 19 has a brake function for bringing the outer periphery of the ring gear 26 ′ into and out of contact with the casing 14, and is switched by a hydraulic piston 27 ′ for the reverse clutch 19. In this case, when only the forward clutch 18 is joined, the turbine shaft 11 and the carrier 22 ′ side are integrated, and the engine rotation is transmitted to the main shaft 28 ′ of the continuously variable transmission unit 16 as it is, and the reverse clutch 1
When only 9 is joined, the rotation of the turbine shaft 11 is inverted and transmitted to the main shaft 28 'of the continuously variable transmission portion 16 on the carrier 22' side.

The continuously variable transmission 16 has a main shaft 28 'integral with the carrier 22' and a sub shaft 29 'arranged in parallel with the main shaft 28' at a predetermined interval. A main pulley 30 'is connected to the sub shaft 29' by the main shaft. Pulleys 31 'are provided, and an endless belt 32' is stretched between the pulleys. Pulley 3
0 ′ and 31 ′ are both divided into two parts,
Reference numerals 01 and 311 are externally fitted to the fixed-side pulley members 302 and 312 so that they cannot be rotated relative to each other and can be separated from and separated from each other. A primary cylinder 33 'and a secondary cylinder 34' are mounted on the movable pulley members 301 and 311 as hydraulic actuators for operating the relative distance from the fixed pulley material. In this case, the fixed pulley member 30 of the main pulley 30 '
2, the winding diameter of the main pulley is increased by approaching the movable pulley material 301, and the winding diameter is reduced by moving the movable pulley 311 away from the fixed pulley material 312 of the sub pulley 31 ', thereby reducing the winding diameter ratio ( The configuration is such that the sub-pulley winding diameter / main pulley winding diameter) is reduced, that is, a low gear ratio (high gear stage) is achieved, and conversely, a high gear ratio (low gear stage) is achieved.

The speed reducer 4 employs a configuration in which a final gear 37 is connected to a gear 35 'integral with the countershaft 29' via a gear train 36 ', and the differential 5 operates in a differential casing (not shown) integral with the final gear 37. It has a well-known configuration in which a mechanism is housed, and a rotational force is allowed to be divided into two and the rotational force is divided and output. The hydraulic circuit of the fluid coupling 2 and the forward / reverse switching unit 15 of FIG. 2 will be described with reference to FIG. The hydraulic circuit includes an oil pump 13, and the discharge oil is supplied to the fluid coupling 2, the forward clutch 18 and the reverse clutch 19 of the forward / reverse switching unit 15, and the continuously variable transmission unit 16.

Here, the oil pump 13 is driven according to the rotation of the engine to change its oil pressure. Therefore, the maximum allowable pressure of the oil discharge is regulated by the line pressure regulator valve 20. To maintain the pressure, the regulator valve 21 operates to regulate the pressure. A part of the line pressure passage 22 is pressure-reduced and adjusted to a set value by a clutch pressure modulator valve 23, passes through a clutch oil passage 24 to a manual valve 28, and further to a pressure adjustment oil passage 25
Is supplied to the first solenoid valve 26 and the second solenoid valve 27 via

The regulator valve 21 has a line pressure passage 22
, A pilot port 222 for receiving pilot pressure from the second solenoid valve 27, a clutch refueling port 223 for supplying oil to the clutch control valve 29, and a drain port 224.
The oil pressure in the line pressure passage is adjusted according to the balance operation between 0 and 31.

The manual valve 28 is linked to a manual shift lever (not shown) for shifting gears, and
The oil passage is switched according to each of the ranges 2 and L, the reverse R range, and the neutral N and parking P ranges. That is, the manual valve 28 is connected to the clutch oil passage 2
4, a forward port 242 communicating with the forward clutch 18 and a reverse port 243 communicating with the reverse clutch 19 are formed. Here, in each of the forward ranges D, 2 and L, the forward clutch 18 is connected to the refueling port 241 and the engine rotation is transmitted to the continuously variable transmission unit 16 as it is. The power is transmitted to the step transmission unit 16.

The fluid coupling 2 allows the relative rotation between the compressor 8 and the turbine 9 when the direct coupling clutch 10 is disconnected and transmits rotation based on the flow resistance, and when the direct coupling clutch 10 is engaged, the fluid coupling 2 is connected to the compressor 8 on the engine output shaft 7 side. The turbine 9 on the turbine shaft 11 side is integrally rotated. The direct connection clutch 10 receives and joins the pressure oil from the connection hydraulic path 32, receives and disconnects the pressure oil from the disconnection hydraulic path 33, and these two paths are connected to the clutch control valve 29. The clutch control valve 29 is connected to a line pressure port 29 connected to the line pressure passage 22.
1. Clutch refueling port 22 of regulator valve 21
3, a pilot port 293 for receiving the pilot pressure of the first solenoid valve 26, a pair of closed ports 294 and 295 connected to the closed circuit 34, a connecting port 296 for connecting the connecting hydraulic path 32, and a disconnect hydraulic path A disconnect port 297 is provided for communication with the port 33. The valve 29 performs a balance operation of the spool 35 based on the hydraulic pressure of the pressure regulating oil passage 25, the elastic force of the spring 38, and the pilot pressure applied thereto.

As a result, the spool 35 is switched and adjusted to the breaking position S1 shown by the solid line, the joining position S2 shown by the two-dot chain line, and the intermediate position. At the disconnection position S1, the oil pressure port 292 communicates with the disconnection port 297 and the hydraulic pressure passage 33, the direct coupling clutch 10 is disconnected, and at the connection position S2, the line pressure port 291 passes between the lands a and b. ,
The closing port 294, the closing path 34 closing port 295, the joining port 296, and the joining hydraulic path 32 communicate with each other.
Join. Particularly, in this case, the first solenoid valve 26 regulates the hydraulic pressure of the pressure regulating oil passage 25 to the pilot pressure in accordance with the commanded duty ratio Du, and supplies the pilot pressure to the pilot port 293. It is configured so that the force can be adjusted.

The fluid coupling 2, the forward / reverse switching unit 15, and the continuously variable transmission unit 16 are controlled by connecting each electromagnetic control valve in the hydraulic circuit to a CVT ECU 36 as control means. The CVT ECU 36 also has a function as a fluid coupling control means, and a main part thereof is constituted by a microcomputer. A built-in storage circuit stores control programs of a CVT control processing routine of FIG. 8 and a clutch control processing routine of FIG. Is stored.

Here, the CVT ECU 36 receives an engine speed N from an engine control unit (not shown).
e, throttle opening θs, vehicle speed V, etc.
The rotation information of the main and sub pulleys 30 'and 31' is captured by a sensor (not shown), and the continuously variable transmission control of the continuously variable transmission is performed according to a known program based on the information.

Hereinafter, the starting control process of the fluid coupling will be described with reference to the control program of FIGS. 8 and 9 and the block diagram of FIG. In the present embodiment, the engine body 1 is started by operating an ignition key (not shown), an engine control unit (not shown) performs fuel supply control, ignition control, and the like in accordance with the engine operation information. The joint 2, the forward / reverse switching unit 15, and the continuously variable transmission unit 16 are controlled.

First, the CVT ECU 36 takes in data such as the throttle opening θs, the engine speed Ne, the vehicle speed V, the main and auxiliary pulley speeds Wp, Ws of the continuously variable transmission, and other data from an engine control unit and sensors (not shown).
If the current vehicle speed V is smaller than the stop determination speed Va, the process proceeds to step 3, and if the vehicle has been started, the process proceeds to step a4. Step a3
First, as shown in FIG. 9, the start process of θs, Ne, V
The latest required data such as the above is taken in, and the required torque is calculated from the current θs and Ne based on the torque calculation map M1 as shown in FIG. This torque calculation map can calculate the required transmission torque T, which is the current generated torque at each throttle opening θs and engine speed Ne. Subsequently, the direct clutch 10 possible joining force transmitting transmission required torque T is calculated based on a reference junction oil pressure calculation map M2 a possible reference junction pressure P _B occurs.

In step b4, a target engine speed Neo is obtained from the target engine speed calculation map M3 in FIG. 5 based on the throttle opening θs. Here, the target engine speed calculation map in FIG. 5 is a map of the target engine speed Neo that can optimize the power performance at each throttle opening θs, and corresponds to each throttle speed indicated by a broken line in FIG. It is created from a value corresponding to the maximum torque value of the opening degree θs. In steps b5 and b6, a difference ΔN between the target engine speed Neo and the actual engine speed Ne is obtained, and the difference ΔN is calculated.
The proportional term ΔP _P is calculated by multiplying N by a proportional coefficient. Here, it is obtained from the proportional term calculation map M4. Step b
7, b8 in sequentially integrates the difference ΔN is calculated integrated value ΣΔN _I, calculates the integral term [Delta] P _I by multiplying the integral coefficient [rho _KI equivalence. In this case, the integral value ΣΔN _I is subjected to a limiter process of a maximum value ΔP _IH and a minimum value ΔP _{IL in} order to prevent divergence of control, and an integral term ΔP _I is set.

In steps b9, b10 and b11, a proportional term ΔP _P (= ΔP _P + ΔP _I ) is derived from a proportional term ΔP _P capable of maintaining control responsiveness and an integral term ΔP _I capable of eliminating control errors and maintaining control stability. ) Is calculated. The adjusted hydraulic pressure corresponding to the proportional integral term ΔP is used to bring the engine speed Ne closer to the target engine speed Neo, so that the direct-coupled clutch 1
It is calculated in order to generate a joining force at 0 and reduce or increase the engine speed. Therefore, the proportional integral term ΔP _PI is subsequently subtracted from the reference joining oil pressure P _B , and the target joining oil pressure P _B is subtracted.
Is calculated, and the duty ratio Du corresponding to the joining hydraulic pressure P is calculated from the duty ratio calculation map M5,
The same value is output.

As a result, as shown by the solid line in FIG. 4, in the starting range S, the engine speed (on the engine output shaft 7 side)
Ne enters the process of increasing the rotational speed at time t1 toward the target engine rotational speed Neo corresponding to the throttle opening θs at that time. The actual engine speed is the target engine speed Ne.
If the actual engine speed attempts to rapidly increase temporarily while reaching o, the target joining oil pressure P is calculated by the PID control in Steps b6 to b10. The joining force of the direct coupling clutch 10 is applied to the engine output shaft 7 as a rotational load, so that the actual engine speed Ne can be prevented from excessively fluctuating. The engine output is used only for increasing the engine speed and the starting torque decreases. Can be prevented, and the actual engine speed can approach the target engine speed Neo relatively early. In the starting region S, the fluid coupling 2 transmits rotation by the flow resistance between the compressor 8 and the turbine 9 and the frictional force associated with the joining force of the direct coupling clutch 10.
Then, the output rotation, that is, the rotation speed No of the turbine shaft 11 gradually increases from the time point t1 toward the time point t2, and after the time point t2, that is, passes through the starting region S, the target engine rotation speed Ne
After o is achieved, when the direct coupling clutch 10 is completely engaged, the rotation substantially coincides with the rotation on the engine output shaft 7 side.

After such a start processing routine, the process reaches step a4 of the main routine. The CVT control process here is a well-known program, that is, the target gear ratio is calculated to hold the target engine speed Neo corresponding to the throttle opening θs, and the main and sub pulleys 30 and 3 are set to achieve the same gear ratio.
The adjustment of the winding ratio of 1 is performed by adjusting the hydraulic pressures of the primary cylinder 33 and the secondary cylinder 34, and thereafter the control process returns to Step a1.

[0029]

As described above, according to the present invention, at the time of starting processing, the clutch engagement hydraulic pressure that can secure the required transmission torque obtained from the actual engine speed of the engine and the throttle opening is calculated as the reference engagement oil pressure. Calculate the joining oil pressure of the fluid coupling that can eliminate the deviation between the actual engine speed and the target engine speed by correcting the reference joining oil pressure by PI control, and drive the fluid coupling with the same joining oil pressure to obtain the actual engine speed. Can be adjusted to the target engine speed, so that even when the actual engine speed changes suddenly, the joining force equivalent to the joining hydraulic pressure of the fluid coupling can be adjusted with good responsiveness and control stability. And the excessive fluctuation of the engine speed can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram of a starting control device for a fluid coupling as one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a power transmission system of a vehicle including the fluid coupling start control device of FIG. 1;

FIG. 3 is an operation explanatory view of a clutch control valve in the start control device for the fluid coupling of FIG. 1;

FIG. 4 is an explanatory diagram of an operation over time in the start control device for the fluid coupling of FIG. 1;

FIG. 5 is a functional block diagram of the starting control device for the fluid coupling in FIG. 1;

FIG. 6 is an engine speed-torque characteristic diagram of the fluid coupling used in the start control device for the fluid coupling of FIG. 1;

FIG. 7 is a control characteristic diagram of a continuously variable transmission in a power transmission system in which the starting control device for a fluid coupling in FIG. 1 is mounted.

FIG. 8 is a flowchart of a control program executed by the starting control device for a fluid coupling in FIG. 1;

FIG. 9 is a flowchart of a control program executed by the fluid coupling start control device of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Fluid coupling 3 Continuously variable transmission 7 Engine output shaft 8 Compressor 9 Turbine 10 Directly-coupled clutch 11 Turbine shaft 16 Continuously variable transmission section 29 Clutch control valve 36 CVTEC Ne Ne Engine speed θs Throttle opening

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-292462 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 59/00-63/48

Claims (1)

(57) [Claims] 1. A fluid coupling comprising: a compressor that rotates integrally with an engine; and a turbine that receives and connects to the compressor by receiving pressure oil from a joint hydraulic path and receives and receives pressure oil from a disconnection hydraulic path. A continuously variable transmission provided in a power transmission system including the fluid coupling and capable of continuously achieving a target gear ratio; and a switching pressure in accordance with a switching command for switching between a joining hydraulic path and a disconnecting hydraulic path of the fluid coupling. A fluid coupling start control device comprising: a clutch control valve for supplying oil; and a fluid coupling control means for switching and controlling the clutch control valve according to engine operation information. The required transmission torque is calculated from the actual engine speed of the engine and the throttle opening, and the clutch connection hydraulic pressure of the fluid coupling according to the required transmission torque is calculated as the reference connection hydraulic pressure. And the above real engine
The proportional integral term corresponding to the deviation between the engine speed and the target engine speed
The joint hydraulic pressure of the fluid coupling, which can be calculated as a corrected hydraulic pressure by PI control and can eliminate the deviation between the two engine rotational speeds so that the actual engine rotational speed becomes the target engine rotational speed according to the throttle opening, is set as the reference hydraulic pressure. PI for joining hydraulic pressure
A start control device for a fluid coupling, wherein the clutch control valve is controlled so as to calculate by adding the correction hydraulic pressure by control and to supply the bonding hydraulic pressure to the bonding hydraulic path.