JPH0450212B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control device for a starting clutch, and more particularly to a device for controlling the transmission capacity of a starting clutch during deceleration.

Conventional technology and its problems Conventionally, there has been a control device that uses a wet multi-disc clutch as a starting clutch and supplies oil pressure that increases in accordance with the engine speed to this clutch to achieve automatic and smooth starting. It has been proposed (Japanese Unexamined Patent Publication No. 1983-75840).

In this type of control device, when decelerating from a running state to a stop, it is necessary to return the starting clutch from a fully engaged state to a half-clutched or disengaged state, and the timing for returning the starting clutch to a half-clutched or disengaged state is determined. It is customary to make a determination when the actual engine speed becomes less than or equal to the set engine speed. In this case, if the set engine speed is set to a relatively high engine speed, the starting clutch returns to the half-clutch or disconnected state while remaining in the high-speed ratio state, resulting in the drawback that the engine brake is not effective. On the other hand, if the set engine speed is set as low as possible in consideration of engine braking performance, the engine is likely to stall when decelerating in a low speed ratio state. Therefore, in the past, the set engine speed was set to a relatively high speed at the expense of engine braking performance.

Purpose of the invention The present invention has been made in view of the above problems, and
The purpose is to provide a starting clutch control device that can reliably prevent engine stalling during deceleration and can effectively operate the engine brake.

Composition of the Invention In order to achieve the above object, the present invention provides a control device for a starting clutch that can continuously control the transmission capacity. The starting clutch is controlled to return from the engaged state to the half-clutch or disengaged state, and the set engine speed is set to decrease as the vehicle speed increases.

That is, the set engine speed when returning the starting clutch from the engaged state to the half-clutch or closed state is set high in a low vehicle speed range and low in a high vehicle speed range. In other words, engine stalling is likely to occur in low vehicle speed ranges, so start control is started from a relatively high engine speed, and engine stalling is less likely to occur in high vehicle speed ranges, so start control is not entered even if the engine speed drops. and can sustain engine braking.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows a schematic structure of a V-belt continuously variable transmission using a starting clutch according to the present invention, in which a crankshaft 2 of an engine 1 is connected to an input shaft 4 via a damper mechanism 3. There is. An external gear 5 is fixed to the end of the input shaft 4, and this external gear 5 meshes with an internal gear 6 fixed to the drive shaft 11 of the continuously variable transmission 10 to transfer the power of the input shaft 4. The speed is decelerated and transmitted to the drive shaft 11.

The continuously variable transmission 10 includes a drive pulley 12 provided on a drive shaft 11, a driven pulley 14 provided on a driven shaft 13, and a V-belt 15 wound between both pulleys. The drive pulley 12 has a fixed sheave 12a and a movable sheave 12b, and a torque cam device 16 and a compression spring 17 are provided behind the movable sheave 12b. The torque cam device 16 generates a thrust proportional to the input torque, and the compression spring 17 generates an initial thrust sufficient to prevent the V-belt 15 from loosening, and these thrusts provide the V-belt 15 with belt tension necessary for torque transmission. ing. On the other hand, similarly to the driving pulley 12, the driven pulley 14 has a fixed sheave 14a and a movable sheave 14b.
A hydraulic chamber 18 for controlling the gear ratio is provided behind. The hydraulic pressure to this hydraulic chamber 18 is controlled by a pulley control valve 43, which will be described later.

A hollow shaft 19 is rotatably supported on the outer periphery of the driven shaft 13, and the driven shaft 13 and the hollow shaft 19 are connected and connected by a starting clutch 20 consisting of a wet type multi-plate clutch. Hydraulic pressure to the starting clutch 20 is controlled by a starting control valve 45, which will be described later. A forward gear 21 and a reverse gear 22 are rotatably supported on the hollow shaft 19, and a forward/reverse switching dog clutch 23 switches either the forward gear 21 or the reverse gear 22 to the hollow shaft 19. It is now connected to The reverse idler shaft 24 has a reverse idler gear 25 that meshes with the reverse gear 22.
, and another reverse idler gear 26 is fixed. Further, the counter shaft 27 is equipped with the forward gear 2.
1 and a reverse idler gear 26, and a final reduction gear 29 are fixed, and the final reduction gear 29 meshes with a ring gear 31 of a differential device 30 to transmit power to an output shaft 32. are doing.

The pressure regulating valve 40 regulates the hydraulic pressure discharged from the oil reservoir 41 by the oil pump 42, and outputs it as line pressure to the pulley control valve 43 and the start control valve 45. The pulley control valve 43 and the start control valve 45 operate the solenoids 44 and 4 in response to a control signal (for example, a duty control signal) output from the electronic control device 60.
6 is operated to regulate the line pressure and output control hydraulic pressure to the hydraulic chamber 18 of the driven pulley 14 and the starting clutch 20, respectively. Therefore, the gear ratio of the continuously variable transmission 10 and the torque transmission capacity of the starting clutch 20 can be freely controlled only by control signals sent from the electronic control device 60 to the solenoids 44 and 46.

FIG. 2 shows a block diagram of the electronic control device 60. In the figure, 61 is a sensor that detects the engine rotation speed N _io (the rotation speed of the input shaft 4), and 62 is a sensor that detects the vehicle speed V (the rotation speed of the output shaft 32). A sensor 63 detects the rotation speed N _put of the driven shaft 13 (the input rotation speed of the starting clutch 20 or the rotation speed of the driven pulley 14), and 64 each shift of P, R, N, D, and L. A sensor 65 detects the position, and a sensor 65 detects the throttle opening. The signals from the sensors 61 to 64 are input to the input interface 66, and the signal from the sensor 65 is converted into a digital signal by an A/D converter 67. be done. 68 is a central processing unit (CPU), 69 is a read-only memory (ROM) in which programs and data for controlling the pulley control solenoid 44 and the start control solenoid 46 are stored, and 70 is a memory sent from each sensor. Random access memory (RAM) 71 is an output interface for temporarily storing signals and parameters, and these CPU68, ROM693RAM70,
Output interface 71, input interface 66 and A/D converter 67 are interconnected by bus 72. Output interface 7
The output of No. 1 is output as a control signal to the pulley control solenoid 44 and the start control solenoid 46 via the output driver 73.

FIG. 3 shows the engagement characteristics of the starting clutch 20 set in the electronic control device 60, and is set so that the torque transmission capacity increases continuously as the engine speed increases. Note that the vertical axis in FIG. 3 may be the clutch oil pressure instead of the transmission capacity, and if the output oil pressure of the start control valve 45 and the input duty ratio are set in a proportional relationship, the vertical axis is the start control. The duty ratio of the solenoid 46 may also be used. At idle speed Ni, the starting clutch 20 is loosely engaged and has a constant creep torque.
Tc is being generated, and the engine speed is at the predetermined value Ns.
When the transmission capacity reaches the maximum Tmax (duty ratio 100%), the starting clutch 20 is engaged.

FIG. 4 shows a speed change diagram set in the electronic control device 60, where Low is the maximum speed ratio of the drive path from the input shaft 4 to the output shaft 32, and High is the minimum speed ratio. N ₁ is when transitioning from shift control to starting control,
That is, this is the set engine speed when the starting clutch 20 is returned from the engaged state to the half-clutch state during deceleration, and the set engine speed _N1 is set to decrease as the vehicle speed increases. Also, _N2
The minimum target in shift control is the engine rotation speed, and the minimum target engine rotation speed _N2 is set higher than the set engine rotation speed _N1 at the time of transition to start control. In particular, in the high vehicle speed range, the difference between the target engine speed N ₂ and the set engine speed N ₁ is set large and a certain hysteresis is provided, so even if sudden deceleration and acceleration are repeated, the shift control and starting control will be controlled. Mutual switching hunting is prevented.

Now, if you slow down slowly while driving at the minimum gear ratio,
The gear ratio is changed to the maximum gear ratio while maintaining the minimum target engine speed _N2 , and when the engine speed becomes below the set engine speed _N1 , the starting clutch 20 returns from the engaged state to the half-clutch state. On the other hand, if a sudden deceleration is performed while driving at the minimum gear ratio, the continuously variable transmission 10
Since the shift to the Low side is delayed, the engine speed drops below the minimum target engine speed _N2 , as shown by the broken line in Figure 4, but the starting clutch 20 is pressed until the engine speed drops below the set engine speed _N1 . Since it remains engaged, engine braking can be applied up to low vehicle speeds. As mentioned above, in low vehicle speed ranges, starting control starts from a relatively high engine speed to reliably prevent engine stalling, and in high vehicle speed ranges, start control does not start even if the engine speed drops. This allows engine braking to continue until the vehicle speed reaches low speeds.

Next, an example of the control method according to the present invention will be explained in the fifth section.
This will be explained according to the diagram.

When control starts, various signals such as throttle opening θ, engine speed N _io , driven shaft speed N _put , and vehicle speed V are input (80), and the set engine speed at the start of start control corresponding to vehicle speed V is determined. N ₁ to 4th
Read from the diagram or calculate (81). Next, the actual engine speed N _io and the set engine speed N ₁ are compared (82), and when N _io >N ₁ , the starting clutch 20 is held in the engaged state and the shift control is continued (83). On the other hand, when N _io ≦N ₁ , the starting clutch 2 is activated with the transmission capacity corresponding to the engine speed N _io.
0 is half-clutched (84). Specifically, the duty ratio corresponding to the engine speed N _io is
It is sufficient to read it from the diagram and output it to the start control solenoid 46.

In the above embodiment, the starting clutch is used in combination with a V-belt type continuously variable transmission, but it is not limited to this and may be used in combination with other continuously variable transmissions, stepped automatic transmissions, manual transmissions, etc. good.

Further, the starting clutch is not limited to a wet type multi-disc clutch, but other types of clutches such as a dry type clutch or an electromagnetic clutch may be used.

Further, in the above embodiment, half-clutch control is used to generate a predetermined creep torque in the starting clutch during idling, but the starting clutch is not limited to this, and the starting clutch may be completely shut off during idling.

Effects of the Invention As is clear from the above explanation, according to the present invention, the set engine speed when returning the starting clutch from the engaged state to the half-clutch or disconnected state is set high in the low vehicle speed range and low in the high vehicle speed range. So,
In low vehicle speed ranges where engine stalling is likely to occur, start control is started from a relatively high engine speed to prevent engine stalling, while in high vehicle speed ranges where engine stalling is less likely to occur, the start clutch is engaged even if the engine speed drops. Since the state is maintained, engine braking can be maintained up to low vehicle speeds.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a V-belt type continuously variable transmission to which the present invention is applied, Fig. 2 is a block diagram of the electronic control device, Fig. 3 is an engagement characteristic diagram of the starting clutch, and Fig. 4 is a shift line. 5 are flowcharts showing specific examples of the control method according to the present invention. 1...Engine, 10...Continuously variable transmission, 20
... Starting clutch, 43 ... Pulley control valve, 44
...Pulley control solenoid, 45...Start control valve, 46...Start control solenoid, 60...Electronic control device.

Claims (1)

[Claims] 1. In a starting clutch control device that can continuously control the transmission capacity, when the actual engine speed falls below the set engine speed during deceleration,
A control device for a starting clutch, characterized in that the starting clutch is controlled to return from a fastened state to a half-clutched state or a closed state, and the set engine speed is set to decrease as the vehicle speed increases.