JPS61132425A - Line pressure control device in stepless speed change unit - Google Patents

Abstract

PURPOSE:To always ensure an optimum line pressure to enhance the responsiveness of a stepless speed change unit, by regulating the line pressure fed to actuators for changing the gear ratio of the speed change unit in accordance with the amount of intake-air in an engine intake-air system, which substantially corresponds to the torque of an engine. CONSTITUTION:In a stepless speed change unit in which the gear ratio is changed by adjusting the groove gaps of drive and driven pulleys having variable effective diameters, by means of hydraulic actuators, there is provided a line pressure regulating means (relief valve) A for adjusting the line pressure discharged from a hydraulic pump and fed to actuators. Further, the line pressure regulating means controls such that the line pressure is controlled in accordance with a line pressure which is set by a line pressure control means C in accordance with the output of an air amount detecting means B.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a V-belt type continuously variable transmission.
The present invention relates to a line pressure control device for a continuously variable transmission that sets belt tension to an appropriate value.

(Prior art) Recently! A V-belt type continuously variable transmission is being implemented as a transmission for both IL and IL. In this V-belt type continuously variable transmission, a V-belt is wound around a driving pulley and a driven pulley, and a hydraulic actuator changes the groove spacing between both pulleys, that is, the widthwise spacing of the V-belt, thereby changing the gear ratio. This is subject to change. Continuously variable transmissions of this type have major advantages such as no shift shock and easy optimization of engine operation, resulting in fuel savings, and are expected to be used as future vehicle transmissions. There are high expectations.

By the way, -1- the transmission possible (
- Considering the torque, this can be promoted as the tension of the V-belt, that is, the force that clamps and presses the V-belt from the width direction by the left and right flanges of the pulley. To explain this point with reference to FIG. 12, the V-belt 3', which is sandwiched from the width direction by a pair of left and right fixed flanges 1' and movable flanges 2', has an inclined surface 1'a of both flanges 1' and 2'. ,
The maximum transmission force will be determined by the frictional force against 2'a. This frictional force is then applied to the V-belt 3'
The friction coefficient for the inclined surfaces 1a' and 2a' is p, the clamping force or pressing force by both flanges 1' and 2' is F, and the angle formed by the inclined surfaces 1a' and 2a' is 2θ, and it is determined by friction. The transmittable torque f is f-2XgXFXcosθ□ (1). The suppressing force F is expressed as -, where A is the pressure-receiving area of the piston 5' in the hydraulic actuator 4' for actuating the movable flange 2', and PL is the pressure acting on the piston 5', that is, the line pressure. AXPL (2). As can be understood from equations (1) and (2), the torque that can be transmitted by the continuously variable transmission ultimately depends on the line pressure P.
Depending on L, the larger the line pressure, the larger the transmittable torque. This line pressure is obtained by adjusting the pump pressure generated by an oil pump driven by the engine using line pressure adjusting means such as a relief valve.

On the other hand, the torque that can be transmitted by the continuously variable transmission and (
Considering the relationship between belt slippage (hereinafter referred to as transmittable torque) and the torque required to drive the vehicle, that is, the transmission torque required for the continuously variable transmission (hereinafter referred to as F-required transmission torque), In order to prevent the belt from slipping on the pulley, it is necessary to satisfy the following relationship (3): required transmission torque ≦transmissible i・lux □ (3). In addition, increasing the transmittable torque, that is, the tension of the V-belt, more than necessary causes the oil pump to do unnecessary work, resulting in poor fuel efficiency and also causing problems with the durability of the V-belt. Become. Of course, from the viewpoint of the durability of the belt I, it is also undesirable to cause the belt to slip.

For this reason, as shown in Japanese Patent Application Laid-Open No. 58-39871, line pressure has been changed according to engine torque,
It has been proposed to improve the durability of the V-belt and save fuel by minimizing the transmittable torque of the continuously variable transmission while satisfying the relationship in equation (3). To explain this point in detail, now the vehicle's drive wheels are
If we consider the case where a driving force of k is generated, the effective radius of this drive wheel is r, the effective radius of the differential gear is 2, the gear ratio of the differential gear is g, and the input torque of the differential gear is T3. The gear ratio of the continuously variable transmission is n,
If the input torque of the S-stage transmission is TI, and the output torque of the continuously variable transmission is T2, the required transmission torque fO is as follows: fo=FkXr/u (4)=T37
□(5) = gXT27 sentence □(6) = n X g x T 1 / 9. - (7). As is clear from equations (4) to (7) above, especially equation (7), the required transmission torque is determined by the input torque of the continuously variable transmission that corresponds to the engine torque. By setting the line pressure, it is possible to satisfy the relationship of equation (3) while keeping the line pressure as low as possible.

By the way, as mentioned above, in order to set the line pressure according to the engine torque number, how to detect this engine torque is the key to effectively using this type of continuously variable transmission. becomes important.

(Object of the Invention) The present invention has been made in consideration of the following two circumstances, and it is possible to detect the engine torque extremely easily and to obtain the optimum setting of the line pressure based on this engine torque. An object of the present invention is to provide a line pressure control device for a continuously variable transmission.

(Structure of the Invention) In order to achieve the above-mentioned [1], in the present invention, the amount of air in the engine intake system is used as a value representative of the engine torque. Specifically, as shown in Fig. 1, the engine drive system includes a driving pulley, a driven pulley, and a V-belt wound around both pulleys, and the groove spacing between the two pulleys is controlled by a hydraulic actuator. The continuously variable transmission is configured to change the gear ratio by changing the gear ratio, and the continuously variable transmission includes: a line pressure adjusting means for adjusting the line pressure supplied to the hydraulic actuator; an air amount detecting means for detecting the amount of air in the engine intake system; , line pressure control means that receives an output from the air amount detection means, sets a line pressure corresponding to the air amount, and outputs a line pressure signal to the line pressure adjustment means. .

With this configuration, the line pressure is set according to the amount of air in the engine intake system, which has a substantially corresponding relationship with the engine torque. It can be made to correspond as such.

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 2 showing the overall outline, l is an engine, and the output (rotation) of the engine l is transmitted to the drive wheels 6 via the clutch 2, gearbox 3, continuously variable transmission 4, and differential gear 5. The power transmission mechanism from the engine 1 to the drive wheels 6 constitutes an engine drive system.

An intake pipe 8 is connected to the engine 1 via an intake manifold 7, and in the intake pipe 8, an air flow meter 144, a throttle valve 9,
A fuel injection valve IO is provided.

The opening degree of the throttle valve 9 is electronically controlled, and therefore the throttle drive mechanism 1
01 is provided. Moreover, the gearbox 3 is
As described later, R (reverse),
The ranges are N (neutral), D (drive), and L (low). Furthermore, clutch 2
The on/off of the transmission and the change of the gear ratio of the continuously variable transmission 4 are automatically performed as will be described later by controlling an actuator using hydraulic pressure.

Next, the clutch 2, gearbox 3, and early gear transmission 4
, the throttle drive mechanism 101 will be sequentially explained based on FIG.

Clutch 2 The clutch 2 is of a friction type and includes a clutch input shaft 21 which also serves as the crankshaft of the engine l, and the input shaft 21.
The latch output shaft 22 is rotatable relative to the latch output shaft 22. A clutch disc 23 is spline-fitted to the clutch output shaft 22, and by press-contacting the clutch disc 23 to a flywheel 24 that is integrated with the clutch input shaft 21, both shafts 21 and 22 are connected. Conversely, when the clutch disc 23 and flywheel 24 are separated, a disconnection state occurs in which the interlocking relationship between the shafts 21 and 22 is cut off. In order to press the latch disk 23 against and separate from the flywheel 24 in this way, the output shaft 2
2, a sleeve 25 is slidably and rotatably fitted into the sleeve 25, and one end of a spring member 27, such as a disc spring, which is swingable about a fulcrum 26 is connected to the sleeve 25. - On the other hand, the other end of the spring member 27 is connected to a clutch pressure plate 28 facing the back surface of the clutch disc 23. As a result, when the sleeve 25 moves to the left in FIG. 3, the clutch pressure plate 28, that is, the clutch disc 23 is displaced to the left in the figure via the spring member 27, resulting in a connected state, and conversely, from this connected state, the sleeve 25 is moved to the left in the figure. When it moves to the left in FIG. 3, it enters the cutting state.

The displacement position of the sleeve 25 in the left direction in FIG. 3 is adjusted by a cylinder device 01 surface 29 serving as a hydraulic actuator. That is, the piston rod 30 of the cylinder device 29 is
One force is connected to the - end of the swinging arm 32 which can swing freely around , and the other end of the swinging arm 32 is connected to iffff.
I am facing the 25th page of resleeve. In addition, the oil chamber 34 defined by the piston 33 of the cylinder device 29 is
It is connected via a pipe 35 to a clutch solenoid valve 36 consisting of a three-way electromagnetic switching valve, and the clutch solenoid valve 36 is connected to a pipe 38 extending from the discharge side of an oil pump 37 and a pipe 40 extending from a reservoir tank 39, respectively. ing. And oil pump 37
A filter 41 is connected to the suction side of the piping 42 extending from the reservoir tank 39 .

The clutch solenoid valve 36 has two solenoids 36a and 36b for connection and disconnection, and when the connection solenoid 36a is energized (the disconnection solenoid 36b is deenergized), the oil chambers of the oil pump 37 and the cylinder device 29 are 3
4 are communicated with each other, the piston rod 30 is extended, and the clutch 2 is connected. The transmission torque of the clutch 2 during this connection becomes stronger as the hydraulic pressure supplied to the oil chamber 34 increases (the pressing force of the flange disk 23 against the flywheel 24 increases). Also, the disconnection solenoid 36b is energized (the connection solenoid 36a
When demagnetized), the oil distribution chamber 34 is opened to the reservoir tank 39, the piston rod 30 is retracted by the return spring 43, and the clutch 2 is disengaged. Further, when both the solenoids 36a and 36b are demagnetized, the oil chamber 34 is sealed, and the screws I and Iζ30 are maintained as they are.

Gearhox 3 The input shaft of the Kia Honx 3 is the clutch output shaft 2.
2, and the clutch output shaft 22 is integrally formed with a first gear 51 and a T52 gear 52 having a smaller diameter than the first gear 51. A gear hook output shaft 53 is arranged parallel to this output shaft 221, and
A gear 54 that constantly meshes with the second gear 52 is disposed between the two shafts 22 and 53. -1- A large-diameter intermediate gear 55 that constantly meshes with the first gear 51 is rotatably fitted into the gear box output lever 53, while
A sleeve 56 is integrated. The clutch gear 5 is always spline-fitted to the sleeve 56, and as the clutch gear 5 is displaced in the axial direction, the clutch gear 5 is connected to the intermediate gear 55 as shown in FIG. Spline fitting is also possible.

In such a gear hook 3, when the clutch gear 57 is at the rightmost position as shown in FIG. 56 to the gearbox output shaft 53, and the direction of rotation of the output shaft 53 at this time corresponds to the forward direction of the automobile. Also, clutch gear 5
7 is displaced to the leftmost position in FIG. , the rotational direction of the output shaft 53 at this time corresponds to the backward direction of the automobile. Furthermore, when the clutch gear 57 is in the intermediate loaf position in the left-right direction in FIG. Shaft 22 and gear hook output shaft 53
It becomes a neutral state in which the interlocking with is cut off.

The displacement position of the clutch gear 57 is adjusted by a cylinder device 58 serving as a hydraulic actuator. That is, when the piston rod 59 of the cylinder device 58 is linked to the clutch gear 57 via the interlocking arm 60 and the piston rod 59 is extended, the clutch gear 57 is displaced to the left in FIG. It has become. This cylinder device 58 has two oil chambers 62 and 63 defined by its piston 61, and the oil chamber 62 and the oil chamber 63 are connected through a piping 64 and a piping 65, respectively.
Through the manual/sulpro 6 consisting of a three-way switching valve
are connected to each. The manual valve 66 is connected to the oil pump 37 via a pipe 67.
They are also connected to the reservoir tank 39 via piping 68, respectively.

Such a manual valve 66 is switched by manually operating an operating lever 70 that is swingable about a fulcrum 69, and the operating lever 70 is pivoted clockwise in FIG. As the range increases, the R range, N range, D range, and L range can be taken sequentially.

In this R range position, the oil chamber 62 is communicated with the oil pump 37, and the oil chamber 63 is connected to the reservoir tank 3.
9, the piston rod 59 extends and the gearbox 3 enters the backward state. In addition, in the N range position, both oil chambers 62 and 63 are opened to the reservoir tank 39, and due to the balancing action of the return spring 71, the piston rod 59, that is, the clutch gear 57 is in the intermediate stroke position, and the gearbox 3 is the neutral position described above. In the D range position, the oil chamber 62 is opened to the reservoir tank 39, the oil chamber 63 is communicated with the oil pump 37, the piston rod 59 is retracted, and the gearbox 3 is It is in the forward state as described above.In addition, when in the L range position,
The manual valve 66 is located at the same position as the D range.
This switch function is used to issue commands for engine braking, which will be described later.

Collection/discharge 1-speed gearbox 4 1111 The continuously variable transmission 4 has an input shaft 8 parallel to 17-
1 and an output shaft 82, and the input shaft 81 has a drive pulley 8.
3, and a driven pulley 84 is provided on the output shaft 82, and a belt 85 is wound between the two pulleys 83 and 84. The drive pulley 83 is composed of a fixed flange 86 that is integrated with the input shaft 81 and a movable flange 87 that can be slidably displaced with respect to the input shaft 81. In order to do this, the V-belt 85 is brought closer to the flange 86 so that the winding radius of the V-belt 85 around the drive pulley 83 becomes larger. Similarly to the drive pulley 83, the driven pulley 84 also has a fixed flange 8 integral with the output shaft 82.
9, and a movable flange 90 that can be slidably displaced with respect to the output shaft 82, and as the hydraulic pressure supplied to the hydraulic actuator 91 increases, the movable flange 90 approaches the fixed flange 89. , (2) The winding radius of the belt 85 around the driven pulley 84 is made large.

The hydraulic actuator 88 is connected to a speed change solenoid valve 94, which is a three-way electromagnetic switching valve, through a pipe 92, and the hydraulic actuator 91 is connected to a speed change solenoid valve 94, which is a three-way electromagnetic switching valve, through a pipe 95. It is connected to the oil pump 37 and to the reservoir tank 39 via piping 96, respectively.

The speed change solenoid valve 94 has two valves, one for speed increase and one for deceleration.
When the speed increase solenoid 94a is energized (the deceleration solenoid 94b is demagnetized), the hydraulic actuator 88 is communicated with the oil pump 37, and the hydraulic actuator 91 is connected to the reservoir tank 39. Since the belt 85 is released, the winding radius of the belt 85 around the drive pulley 83 becomes larger, while the winding radius around the driven pulley 84 becomes smaller, and the output shaft 82 enters a speed increasing state where its rotational speed increases (speed ratio small). Also,
When the deceleration solenoid 94b is energized (the speed increase solenoid 94a is demagnetized), on the contrary, the hydraulic actuator 91 is communicated with the oil pump 37, and the hydraulic actuator 88 is opened to the reservoir tank 39. The winding radius around the driving pulley 83 becomes smaller, while the winding radius around the driven pulley 84 becomes larger, and the output shaft 82 enters a deceleration state where its rotational speed decreases (
variable speed Hokuten). Of course, the gear ratio is the number of revolutions of the input shaft 81 divided by the number of revolutions of the output shaft 82 (■ Belt 85
(the winding radius for the driven pulley 84 divided by the winding radius for the drive pulley 83).

When both the renoids 94a and 94b are demagnetized, the line pressure after being regulated by the relief valve 97, which will be described later, is supplied to the actuator 91 on the driven boob 984 side via the throttle 94c. , the actuator 88 on the drive pulley 83 side is sealed, thereby
With the gear ratio set at a predetermined speed ratio, a tension corresponding to the in-pressure indicated by L is applied to the V-bell I.85. In addition,
The reason why the line pressure is supplied to the driven pulley 84 side is that the continuously variable transmission 4 acts as a speed reducer and the transmission I/Lux on the driven pulley 83 side is larger than that on the driving pulley 83 side. The reason why the actuator 88 on the side of the boot 983 is sealed is to prevent the set gear ratio from changing.

Throttle drive mechanism 101 The throttle drive mechanism 101 includes a throttle valve 9
Cylinder device 10 as a hydraulic actuator for driving
2. This cylinder device 102 has two oil chambers 104 .
105 is defined, and a piston rod 106 extending from the piston 103 is connected to the throttle valve 9. ” - The oil distribution chamber 104 is connected to the oil chamber l via the pipe 107.
.

5 are respectively connected to three-way electromagnetic switching valves 10 via piping 108.
The switching valve 109 is connected to the oil pump 37 via a pipe 110 and to the reservoir tank 39 via a pipe 111.

As a result, the two solenoids 109a of the switching valve 109
, 109b, when the solenoid 109a for increasing the opening degree is energized (the solenoid 109b is demagnetized), the oil chamber 1
04, the oil chamber 105 is opened to the reservoir tank 39, and the opening degree of the throttle/help 9 is increased.

Conversely, when the opening reduction solenoid 1ζ 109b is energized (the solenoid 109a is demagnetized), oil is supplied to the oil chamber 105, while the oil chamber 104 is connected to the reservoir tank 39.
The opening degree of the throttle valve 9 is reduced. When both the threaded blades 109a and 109b are demagnetized, both oil chambers 104 and 105 are sealed, and the opening degree of the throttle valve 9 is maintained.

The oil pressure 111 discharged from the oil pump 37, that is, the pump pressure, is regulated to a predetermined line pressure as described later by the relief valve 97 as a line pressure regulating means, and then the pressure is regulated to a predetermined level of line pressure as described below. 36.66.
94.109.

In FIGS. 2 and 3, 131 is a control unit, to which the outputs of the sensors 132 to 141 are input; 36, the speed change solenoid valve 94, the relief valve 97, and the electromagnetic switching valve 109 are outputted.

To explain each of the sensors 132 to 141, the sensor 132 is a throttle sensor that detects the opening degree of the throttle valve 9. The sensor 133 is a rotation speed sensor that detects the rotation speed NE of the engine 1 (same as the rotation speed E of the clutch input shaft 21 in the embodiment). Sensor 13
4 is a rotation speed sensor that detects the rotation speed C of the clutch output shaft 22. The sensor 135 is connected to the R of the operating lever 7o,
This is a position sensor that detects the N, D, and L positions.

The sensor 136 detects the rotation speed N of the input shaft 81 of the continuously variable transmission 4.
This is a rotation speed sensor that detects P. The sensor 137 is a vehicle speed sensor that detects the rotational speed Ns of the output shaft 82 of the continuously variable transmission 4, that is, the vehicle speed ■. Sensor 13B is an accelerator sensor for detecting the opening degree of accelerator pedal 142. The sensor 139 is a pre-drive sensor for detecting whether the brake pedal 143 is being operated. The sensor 140 is an air amount sensor that detects 111 the amount of air flowing through the engine intake system. The sensor 141 is a slope sensor that detects the slope of the road surface on which the vehicle is running.

Next, the contents of control by the control unit 131 will be explained in order based on the flowcharts shown in FIGS. 4 to 6 and 10, divided into overall control, clutch control, gear ratio and throttle control, and line pressure control. do.

Overall control (Figure 4) Figure 4 shows the overall processing system.
After the system is initialized in step 1, various data necessary for control are input in step 202, and then clutch control in step 203, gear ratio control in step 204, throttle control in step 205, and line pressure control in step 206 are performed. It will be.

Clutch control (FIG. 5) First, in step 221, it is determined whether the operating lever 70, that is, the gearbox 3 is in the N range. If not in the N range, the process moves to step 222. In this step 222, it is determined whether the vehicle speed is high (for example, 10 km/h or more). If the vehicle speed is high, a vehicle speed flag is set in step 223, and then step 224
Move to.

In step 224, the differential value E' of the rotation speed E of the clutch input shaft 21 is determined, and it is determined whether or not the differential value E' is positive indicating an increase in the rotation speed. If so, the process moves to step 225. This step 2
25, it is determined whether or not the rotation speed E of the clutch input shaft 21 is larger than the rotation speed C of the clutch output shaft 22.
If it is tc, the process moves to step 226. In step 226, the connecting solenoid 36a of the clutch solenoid valve 36 is energized, while the disconnecting solenoid 36b is deenergized to connect the clutch 2, that is, increase its transmission torque. Also, in step 225, E
If it is determined that it is not tc, the process moves to step 228, where the connection and disconnection solenoids 36a and 36b of the taratch solenoid valve 36 are both demagnetized to maintain the transmission torque of the clutch 2 as it is.

If it is determined in step 224 that E'>0 is not true, the process moves to step 227, where it is determined whether E<C. When EtC, the process moves to step 226, clutch 2 is connected, and Et
If not c, the process moves to step 228 and the connected state of the clutch 2 is maintained as it is.

The process from step 224 to 225 described above is based on the assumption that the rotation of the clutch input shaft 21 is increasing due to the heat, and the process from step 225 to 226 is based on the assumption that the rotation speed E of the clutch input shaft 21 is increasing to the clutch output shaft 22. Since this is the case when the rotational speed C is higher than the rotational speed C, it is necessary to increase the transmission torque of the clutch 2, and therefore, the connection is performed in order to increase the transmission torque of the clutch 2. This case corresponds to, for example, a so-called half-clutch state when starting an automobile. The engagement speed of the clutch 2 at this time is increased as the rate of change E' of the engine speed is larger and as the vehicle speed is larger, and similarly, the degree of change of the gear ratio of the continuously variable transmission 4 to the upshift side is increased. The larger it is, the larger it will be. Further, the flow from step 225 to step 228 is when the transmission torque of the clutch 2 is exactly balanced, so the clutch 2 is held in that state, and in this case, for example, it corresponds to a steady running state. .

Conversely, the flow from step 224 to step 227 is based on the assumption that the rotational speed of the clutch input shaft 21 is decreasing, and the transfer of torque between the clutch input shafts 21 and 22 occurs exactly at step 224. Since the flow from step 225 is reversed, the determination in step 227 is changed to step 2.
In contrast to the determination in step 25, it is checked whether E<C. Note that the flow from step 227 to step 226 corresponds to, for example, the case where the operation lever 70 is changed to the D range while driving with the control lever 70 set to the N range, and in this case as well, the so-called half-clutch state is reached. Form. Further, the flow from step 227 to step 228 corresponds to, for example, a deceleration traveling state using engine braking.

- On the other hand, if it is determined in step 221 that the vehicle is in the N range, the vehicle speed flag is reset in step 229, and then the process proceeds to step 230. This step 2
30, the connection solenoid 36a of the clutch clutch make valve 36 is deenergized, while the disconnection solenoid 36b is energized to disconnect the clutch 2. That is, in this case, it is clear that the driver himself requests a neutral state, so the clutch 2 is unconditionally disengaged.

If it is determined in step 222 that the vehicle speed is low, the process moves to step 231, where the accelerator pedal is pressed down.
It is determined whether or not 42 is turned ON by being stepped on. When this accelerator is not ON, it means that the output of engine l is not requested, so the process moves to step 232.
It is determined whether the vehicle speed flag is set. When the 11j speed flag is set, it means that the vehicle speed has not decreased to the last minute, and in this case, the process moves to step 233, where it is determined whether the brake pedal 143 is depressed and turned ON. It is determined whether or not.

Then, if the brake is ON, step 23
Move to 4, and here the engine speed NE is 150 Or
If it is determined that it is below pm, the process moves to step 230 via step 229 (clutch 2 is disengaged). If it is determined in step 233 that the brake is not turned on, the process moves to step 235, and if it is determined here that the engine speed NE is 1100 Orp or higher, the process goes through steps 229 and 229 to step 235. Processing 230 is performed (clutch 2 is disengaged). If it is determined in step 234 that the engine speed NE is not less than 150° rpm, and in step 235, the engine speed NE is determined to be 1100° rpm or less.
If it is determined that it is not less than rp, step 224
The process described above is performed.

In this way, the engine rotation speed N is used as a criterion for determining whether or not to disengage the clutch 2 when the brake is turned on or off.
The reason why the magnitude of E was made different was to provide some leeway to avoid the danger of engine stalling, considering that the drop in vehicle speed is slower when the brakes are on (ON) than when the brakes are not on. . Note that when it is determined in step 232 that the vehicle speed flag is not set, the process of step 230 is performed via step 229 to prevent engine stalling (clutch 2 is disengaged).

Gear ratio and throttle control (Fig. 6) First, in step 241, the state of change in the accelerator opening α is determined. If the accelerator opening α is increasing, the gear change flag is set to 1 in step 242, and then step 243. In this step 243, the target acceleration GT is set from the change in the accelerator opening degree α minus the star Δα. That is, as shown in FIG. 7, the larger the accelerator opening degree increaser, the larger the acceleration desired by the driver, and the larger the target acceleration GT is set. After that, in step 244, the current vehicle speed V is set as the vehicle speed VT, and then the process moves to step 245.

In step 245, the running resistance F of the vehicle is determined depending on the gradient of the road surface on which the vehicle is running and the vehicle speed VT.
Calculate L. This running resistance FL is calculated as follows: (pLy+s inK) m
It is obtained by adding the calculated values of the river s, D, and VT2 to the calculated value of W. To explain this point diagrammatically with reference to FIG. 8, this corresponds to finding a point x1 corresponding to the vehicle speed VT on the constant traveling resistance line β in the third quadrant of FIG.

Then, in step 246, the target acceleration GT
The driving force Fe required to achieve this is calculated. This driving force Fe is obtained by adding the calculated value of GT -W to the running resistance FL. This means that, in FIG. 8, the equal power line of the engine 1 passes through the point The relevant X' of γ
This corresponds to finding the driving force at two points in time.

After step 246, in steps 247 and 248, the engine operating characteristics to achieve the driving force Fe, the target engine speed NeT and the target throttle opening that achieve the most fuel efficiency to achieve the engine operating characteristics are determined. Tht is calculated. Both target values N
aT, T ht are the driving force F in FIG.
The intersection point X3 between the constant power line γ', which is obtained by mapping the constant power line γ corresponding to e to the first quadrant of FIG.
The engine speed corresponding to 3 is the target engine speed Ne
T, and the throttle opening corresponding to this intersection x3 is set as the target throttle opening Tht (step 248
).

Next, in step 249, it is determined whether or not the current engine speed NE is greater than the 11 standard engine speed NET. If NE is greater than NET, step 2 is executed.
After outputting the shift I/up signal at 50, select NE or N again.
If it is less than ET, a downshift signal is output in step 251, and then the process moves to step 252. Note that when the shift i/down signal is output in step 251, the larger the difference between [1 mark acceleration + N a 'r and the current acceleration G, the higher the speed at which the gear ratio of the continuously variable transmission 4 is changed, that is, the gear ratio. The rate of change d n /d t is set to be large. This gear ratio change speed d n
/dt can be adjusted by controlling the shift solenoid valve 94 by duty, as shown in FIG. The tute ratio is set according to the line pressure supplied to 94. pressure).

In step 252, it is determined whether or not the current throttle opening Th is larger than the target throttle opening Tht. If Th is larger than Tht, the throttle opening is decreased in step 253; Th
If it is not greater than t, the throttle opening is increased.

If it is determined in step 241 that there is no change in the accelerator opening, the process moves to step 255, where the shift flag is determined. If it is determined that the shift flag is 1, the processing from step 243 described above will be performed.

The processing from step 255 to step 243 onwards is as follows:
As is clear from the explanation up to now, like the processes from step 242 to step 243 onward, the control is performed during constant acceleration driving.

On the other hand, when it is determined in step 241 that the accelerator opening degree has been decreased, the shift flag is sequentially set to O in step 256, and the vehicle speed flag in step 257 (the vehicle speed flag in FIG. 6 is the vehicle speed flag in FIG. 5). 2) is set to O, the process moves to step 258.

In this step 258, it is determined whether or not the position 8-70 of m-crop is in the L range. If it is determined that it is not in the L range, the process moves to step 259. In step 259, it is determined whether the vehicle speed flag is 1 or not.
9, the vehicle speed flag is 0. In this case, the current vehicle speed V is set to VT in step 260, the vehicle speed flag is set to 1 in step 261, and then the target acceleration GT is set in step 262. 6, the processing from step 245 described above is performed. Once step 261 is passed, the vehicle speed flag is set to 1 in step 259.
In this case, steps 260 and 261 are performed.
The processing from step 262 to step 245 and subsequent steps is performed without passing through. In this way, the route passing through step 262 is used as control during constant-speed driving to maintain the vehicle speed at the current vehicle speed.

The position 8-70 is set to L by the operation in step 258.
If it is determined that the vehicle is in the range, this means that a large deceleration is required, so the process moves to step 263, where the gear ratio n is set so as to obtain a large deceleration according to the vehicle speed. be done. Thereafter, it is determined whether the actual gear ratio obtained by dividing the input shaft rotation speed Np of the continuously variable transmission 4 by the output shaft rotation Ns is larger than the gear ratio n set in step 263, which is indicated by -. Ru. And N p / N
When s > n, the throttle opening is decreased at step 267 after upshifting is performed at step 265, and after shifting down at step 266 when N p /N s > n is not satisfied. In this way, the route passing through step 263 is used as control during engine braking operation.

Note that after decreasing the accelerator opening degree, if the accelerator opening degree is maintained at the reduced position, the process moves from step 241 to step 255, but in step 255, if the shift flag is O, Since the determination is made (because steps 241 to 256 have been passed in the previous control), the process moves to step 258, and the above-described constant speed operation or engine brake operation is controlled.

Line pressure control (Fig. 10) First, in step 272, the current gear ratio n is calculated from the input and output rotational speeds Np and Ns of the continuously variable transmission 4, and then in step 273, the air amount QA of the engine intake system, i.e. The output torque Te of the engine 1 is calculated from the intake air amount. Note that this engine torque Te is based on the stoichiometric air-fuel ratio (14
, 7) is calculated assuming that combustion is performed. After this, in step 274, the output torque Te of the engine l is
The reference line pressure PL is calculated from the speed ratio n at step 271. Of course, this reference line pressure PL is
Using the above equation (7), the necessary minimum size is determined to satisfy the above equation (3).

After this, in step 275, it is determined whether the clutch 2 is completely connected. This clutch 2 is completely +i
Whether or not they are connected is determined, for example, by comparing their input shaft rotational speeds.

When this clutch is fully engaged, the process moves to step 276, and from this step 276 step 2
81, the reference line pressure PL is corrected.

This correction will be sequentially explained for each step 276 to 280.

Step 276 When the absolute value of the target gear ratio change speed dn/dt (see explanation of step 251) is larger than the predetermined set value,
Since the V-belt 85 of the continuously variable transmission 4 is likely to slip, the reference line pressure PL is corrected in the direction of increasing it.

Step 277 is a correction based on the shift direction; when shifting up, the transmitted torque becomes smaller, so the line pressure is corrected to be smaller; when shifting down, on the other hand, the line pressure is corrected to be larger.

Step 278 This is a correction based on a change in accelerator opening α (the same applies to changes in intake pressure), and when the absolute value of the rate of change dα/dt in accelerator opening is larger than a predetermined set value, the line pressure is corrected in the direction of increasing it. do. This correction is made in order to respond to changes in the output torque of the engine 1 with good response.

Step 279 Correction during braking, brake pedal 143
When the pedal is depressed, the line pressure is corrected to increase. This is to cope with an increase in transmission torque corresponding to an increase in drive load due to the brake and release of inertia from the engine 1 due to a decrease in engine speed.

Step 280 Correction based on acceleration/deceleration, d v representing acceleration/deceleration
/ d When the absolute value of t is larger than the predetermined setting value,
Correct to increase line pressure. In addition, during sudden braking when the brake pedal 143 is depressed greatly, that is,
During sudden deceleration when dv/dt (negative value in this case) is smaller than a predetermined set value, impact is applied to the V-belt 85 due to the release of inertia from the engine and a sudden increase in transmission torque due to a sudden increase in driving load. To avoid this, correct the line pressure to reduce it. In other words, in this case, instead of increasing the transmission torque of the continuously variable transmission 4 by dealing with the increase in the transmitted I/lux, priority is given to the durability of the belt 85, and even if the belt 85 slips, Even reduce line pressure.

After the line pressure is corrected in step 276 to 286 as described above, it is determined in step 281 whether or not the position of operating lever 70 is in the neutral range, and when it is determined that it is in the neutral range, Since driving force transmission is not required, the line pressure is corrected to be lower. Then, in step 283, a current corresponding to the final line pressure after the various corrections described above is output to the relief valve 97. Further, when it is determined in step 281 that the range is not in the neutral range, the process proceeds to step 283 without passing through step 282.

Here, if it is determined in step 275 that the clutch is not fully engaged, then after passing through step 284, the processes from step 276 onwards are performed. In step 284, the line pressure is corrected based on the clutch control signal.

To prove this point with reference to Figure 11, (a) in Figure 11 shows the change in accelerator opening, and (b) shows the engine output torque (calculated value), clutch transmission torque, and V
Each change in the transmittable torque of the belt 85 (continuously variable transmission 4) is shown, and (C) also shows the change in the engine rotation speed and the clutch output shaft rotation speed. In this Figure 11,
From the stopped state, the clutch 2 starts to be connected at time t2, which is slightly delayed from the time t1 when the accelerator opening is increased, and the transmission torque of the clutch 2 is gradually increased, and the clutch output shaft rotation speed is increased accordingly. also increases. Eventually 13
At time t4, the clutch transmission torque is temporarily set to a value (maintained in a half-clutch state), and at time t4, the engine speed and clutch output shaft speed match (clutch 2 is substantially fully engaged). ). After this, the clutch transmission torque will further increase by the amount of the extra capacity. Then, when the accelerator opening degree starts to decrease at time t5, clutch 2 is disengaged at time t6, which is delayed from this, and at the time of clutch disengagement, the line pressure is corrected to become smaller, causing unnecessary The time the line pressure is kept high is shortened.

In the above-mentioned operating condition, the transmission torque of the V-belt 85 is maintained until the clutch 2 is fully engaged (1+
up to that point), that is, during the clutch engagement process, the clutch transmission torque is followed, and after this complete engagement of the clutch 2, the engine output torque is followed. Then, when the clutch 2 is disengaged, the clutch transmission torque is made to follow the clutch transmission torque at time 17 when the transmission torque of the clutch 2 becomes smaller than the engine output torque. That is, in the clutch engagement process in which the engine drive system is controlled by the transmission torque of the clutch 2, the reference line pressure PL corresponding to the engine output torque in step 274 is adjusted so that the line pressure matches the required transmission torque of the V-belt 85. This prevents the V-belt 85 from slipping during the clutch connection process.

In particular, as in the embodiment, if the transmission torque (line pressure) of the V-belt 85 during the clutch connection process is based on the clutch control signal, slippage of the belt 85 can be prevented. Although it is possible to set the pressure as low as possible and for a relatively short time, the oil pump 3
7 will not have to do unnecessary work, which will improve fuel efficiency.''
will be planned.

Although two embodiments have been described above, the present invention is not limited thereto, and includes, for example, the following cases.

(Each valve 36.66.1 other than 0-speed solenoid 94)
For No. 09, the pressure of the oil pump 37 may be supplied via a constant pressure valve. For No. 109, which particularly requires duty control, it is recommended to supply constant pressure in order to facilitate the duty control. This is preferable.

(2) The throttle valve 9 may be driven by other driving means such as a step motor, or may be mechanically linked to the accelerator pedal 142 as in a normal vehicle.

■Air m in step 273: The initial performance of the engine torque Te based on Q A may not be determined uniformly based on the stoichiometric air-fuel ratio, but may be changed according to changes in the air-fuel ratio, i.e. Depending on the engine, a region in which it is operated at a specific air-fuel ratio other than the stoichiometric air-fuel ratio is set in advance, and the fuel injection I) 118m from the fuel injection valve 10 is adjusted according to this operating region ('It control). There are also systems that do this, but in this case, the same 1 ton of air
Even in QA, the engine torque Te may be calculated or the calculation result at the stoichiometric air-fuel ratio may be corrected based on the signal indicating that the engine is in the specific operating region. In addition, corresponding to the region operated with the smallest air-fuel ratio (if the air fttQA is the same, the engine torque T
(corresponding to a region where e becomes large), the engine torque Te may be calculated based on the air amount QA.

(Effects of the Invention) As is clear from the above, the line pressure is set based on the amount of air in the engine intake system that corresponds to the engine torque, so the line pressure is adjusted according to the engine torque. 1- is preferable because it allows the optimal setting of the speed change and the effective use of the continuously variable transmission. Furthermore, the line pressure can be set optimally by responding to changes in the air amount in the engine intake system, that is, changes in engine I/lux, which is advantageous in terms of ensuring responsiveness. Of course, since the amount of air in the engine intake system can be detected extremely easily, this method is also advantageous in terms of ease of implementation.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the present invention. FIG. 2 is an overall schematic diagram showing an embodiment of the present invention. FIG. 3 is an overall system diagram showing one embodiment of the present invention. FIG. 4, FIG. 5, FIG. 6, and FIG. 1O are flowcharts showing an example of control according to the present invention. FIG. 7 is a diagram showing the relationship between target acceleration and the amount of change in accelerator opening. FIG. 8 is a diagram showing an example of obtaining the target engine speed and target throttle opening required to achieve the target acceleration. FIG. 9 is a diagram showing the relationship between the duty ratio and the target gear ratio change speed. FIG. 11 is a diagram showing how to set the transmission i and torque of the V-belt. FIG. 12 is a diagram illustrating the relationship between the transmittable torque of the V-belt and the line pressure. 1: Engine 4: Continuously variable transmission 37: Hydraulic pump 83: Drive pulley 85: V belt 84: Followed pulley 88.91 + hydraulic actuator 97: Relief valve (line pressure adjustment means) 131: Control unit 140: Air amount sensor No. 12 Figure 0 Box 1 Box Nri 1

Claims (1)

[Claims] (1) Interposed in the drive system of the engine, comprising a drive pulley, a driven pulley, and a V-belt wound around both pulleys,
In a continuously variable transmission in which the gear ratio is changed by changing the groove spacing between the two pulleys using a hydraulic actuator, a line pressure adjusting means for adjusting line pressure supplied to the hydraulic actuator; and air in an engine intake system. air amount detection means for detecting the amount of air; and line pressure control means for receiving the output from the air amount detection means, setting a line pressure corresponding to the air amount, and outputting a line pressure signal to the line pressure adjustment means. A line pressure control device for a continuously variable transmission, comprising: