JPH07103907B2 - Start clutch control method for automatic transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting clutch control method for an automatic transmission, and more particularly to a creep force control method for a sliding start clutch capable of arbitrarily controlling a transmission torque.

Conventional technology and its problems Conventionally, a sliding clutch such as a wet clutch or a dry clutch is used as a starting clutch of an automatic transmission, and its transmission torque capacity is controlled by an actuator so that an arbitrary starting characteristic can be obtained. There are known ones (see JP-A-60-241530 and JP-A-60-176925). In the case of this type of starting clutch, it is possible to perform slip control at the time of idling of the running range so as to generate a creep force similar to that of the fluid coupling, for the purpose of smoothness of starting, prevention of backward movement at the time of starting on a slope, and the like.

However, it is impossible to arbitrarily change the creep force in response to the driver's request because the above-mentioned starting clutch is preset to generate a certain amount of creep.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to automatically change a creep force according to a driver's request and to prevent an unexpected change in creep force of a driver. It is to provide a starting clutch control method for an aircraft.

In order to achieve the above-mentioned object, the present invention is provided with a slip-type starting clutch capable of arbitrarily controlling the transmission torque, and the starting clutch is slip-controlled so as to generate a predetermined creep force during idling of a running range. In automatic transmission,
In the non-running range state, the engine is warmed up, and the engine speed when the state where the throttle opening is opened by a certain amount or more is continued for a certain period of time is memorized, and after switching to the driving range, the above The transmission torque capacity of the starting clutch is controlled so that the creep force corresponding to the stored engine speed is generated.

That is, when the driver wants to change the creep force, in the non-running range, the throttle opening is opened in the warmed-up state, the engine is idle, and the creep force is changed according to the engine speed at that time. It is a thing.
Further, the control of the present invention is in a non-running range, in a stable state such as a warm-up state, and further, on condition that the throttle opening is continuously opened over a certain opening, the creep force change unexpected by the driver is made. Is being prevented.

Description of Embodiments FIG. 1 shows a V-belt type continuously variable transmission which is an example of an automatic transmission according to the present invention. A crankshaft 2 of an engine 1 is connected to an input shaft 4 via a damper mechanism 3. An external gear 5 is fixed to the end of the input shaft 4, and the external gear 5 meshes with an internal gear 6 fixed to the drive shaft 11 of the continuously variable transmission 10 to reduce the power of the input shaft 4. And transmitted to the drive shaft 11.

The continuously variable transmission 10 includes a drive pulley 12 provided on a drive shaft 11,
The driven shaft 13 is composed of a driven pulley 14 and a V belt 15 wound between the pulleys. 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 force proportional to the input torque, and the compression spring 17 generates V
The belt 15 generates an initial thrust that does not slacken, and these thrusts apply the belt tension required for torque transmission to the V-belt 15. On the other hand, the driven pulley 14 is also the drive pulley 12
Similarly, it has a fixed sheave 14a and a movable sheave 14b, and behind the movable sheave 14b is a hydraulic chamber 18 for gear ratio control.
Is provided. The hydraulic pressure to the hydraulic chamber 18 is controlled by a pulley control valve 43 described later.

A hollow shaft 19 is rotatably supported on the outer periphery of the driven shaft 13, and is disconnected from the hollow shaft 19 of the driven shaft 13 by a starting clutch 20 composed of a wet multi-plate clutch. The starting clutch
The hydraulic pressure to 20 is controlled by a start control valve 45 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
Thus, either the forward gear 21 or the reverse gear 22 is connected to the hollow shaft 19. The reverse gear 24 meshes with the reverse gear 22 on the reverse idler shaft 24.
25 and another reverse idler gear 26 are fixed.
A counter gear 28 that meshes with the forward gear 21 and the reverse idler gear 26 at the same time and a final reduction gear 29 are fixed to the counter shaft 27, and the final reduction gear 29 meshes with a ring gear 31 of the differential device 30. , The power is transmitted to the output shaft 32.

The pressure regulating valve 40 regulates the hydraulic pressure discharged from the oil sump 41 by the oil pump 42 and outputs it as a 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 actuate the solenoids 44 and 46 by the duty control signal output from the electronic control unit 60 to control the line pressure to control the hydraulic chamber 18 and the start clutch 20 of the driven pulley 14, respectively. The control oil pressure is output to.

Specific structures of the control valves 43 and 45 are, for example, a combination of a spool valve 50 and a solenoid valve 52 as shown in FIG.
As shown in the figure, the ball-shaped valve body 53 may selectively open and close the input port 54 and the drain port 55 to output the control hydraulic pressure to the output port 56, which may be a single 3-port solenoid valve. For example, when the control valves 43 and 45 are composed of the spool valve 50 and the solenoid valve 52 as shown in FIG. 2, if the duty ratio output from the electronic control unit 60 to the solenoid valve 52 is D, the spool valve The output hydraulic pressure P _{OUT of} 50 is given by the following equation.

_{P OUT × A 1 = P L} × D × A 2 + F in ... (1) where the land of A _1, A ₂ each spool valve 50 5
The pressure receiving areas of 0a and 50b, P _L is the line pressure, and F is the spring load of the spring 51.

Further, when the control valves 43, 45 are composed of a single solenoid valve as shown in FIG. 3, the output hydraulic pressure P _OUT is given by the following equation.

P _OUT = P _L × D (2) In formulas (1) and (2), A ₁ , A ₂ , P _L and F are constant values, so the duty ratio D and the output hydraulic pressure P _OUT are Proportional.
On the other hand, since the gear ratio of the continuously variable transmission 10 and the transmission torque of the starting clutch 20 can be controlled by the output oil pressure P _OUT , the gear ratio of the continuously variable transmission 10 and the transmission torque of the starting clutch 20 can be freely adjusted by the duty ratio D. You will have control.

FIG. 4 shows a block diagram of the electronic control unit 60, in which 61 is a block diagram.
Is a sensor for detecting the engine speed (may be the speed of the input shaft 4), 62 is a sensor for detecting the vehicle speed, 63 is the speed of the driven shaft 13 (the input speed of the starting clutch 20 or the driven pulley).
A sensor for detecting the number of revolutions of 14), 64 is P, R, N, D,
A sensor that detects each shift position of L, a sensor that detects a throttle opening degree, a sensor that detects an engine water temperature, and a sensor that detects the engine water temperature. Is converted into a digital signal by the A / D converter 68. 69 is a central processing unit (CP
U), 70 is a read-only memory (ROM) in which programs and various data for controlling the pulley control solenoid 44 and the start control solenoid 46 are stored, and 71 is a temporary signal or parameter sent from each sensor. Random access memory (RAM) to be stored in the RAM, 72 is a non-volatile memory that stores an average engine speed N _Nave in a non-running range, which will be described later, and 73 is an output interface.
OM70, RAM71, non-volatile RAM72, output interface 7
3. The input interface 67 and the A / D converter 68 are interconnected by a bus 74. The output of the output interface 73 is output as a duty control signal to the pulley control solenoid 44 and the start control solenoid 46 via the output driver 75.

The starting clutch 20 is always cut off because the duty ratio of the starting control solenoid 46 is 0% in the non-driving range or the oil passage is cut off by a manual valve (not shown), and the starting clutch 20 is started during idling in the running range. A low duty ratio signal is output to the control solenoid 46, and slip control is performed so as to generate a predetermined creep force. In the conventional automatic transmission, the creep force is controlled to a substantially constant value, but in the present invention, the creep force can be freely changed according to the intention of the driving vehicle.

Next, a control method of the starting clutch according to the present invention, particularly a creep force changing control method will be described with reference to FIGS.

First, the idle speed when not performing the standard idle speed N ₁ and is a standard idling speed N ₂ of the driving range is set in advance, the following creep force changes the non-driving range to the electronic control unit 60 is N ₁ , N ₂ is maintained.

When the control is started, it is determined whether the shift position at that time is in the N, P non-running range or the D, L running range (80), and when it is in the non-running range, the control factor i = 0
It is determined whether or not (81). This determination is for determining whether the preceding cycle was the running range or the non-running range, i = 0 indicates the running range, and i = 1 indicates the non-running range. If i = 0, it means that the state one cycle before is the traveling range, that is, immediately after switching from the traveling range to the non-traveling range.
The n data of the engine speed N _N in the non-running range stored in the memory described later is initialized and the data is erased (82). However, the average engine speed _N Nave stored in the nonvolatile memory at the time of this initialization is not deleted.

Next, the factor i is defined as 1 (83), and then it is compared whether the engine water temperature is higher than a constant value T ₀ (84). When it is high, it is compared whether the throttle opening is larger than a constant value θ _0. To (85). The comparison of the engine water temperature with the constant value T ₀ is
This is for determining whether or not the engine is warmed up, and it is preferable to detect the lubricating oil temperature inside the transmission, but the engine water temperature can be used instead. Further, the reason why the throttle opening is compared with the constant value θ ₀ is to determine that the driver intentionally depresses the accelerator pedal, and to distinguish the operation of the choke button and the like.

When the engine water temperature is higher than a constant value T ₀ and the throttle opening is larger than a constant value θ ₀ , the engine speed at that time
Detects N _N (86), and stored sequentially in the memory, to ensure the most recent n data (87). Then, when all n engine speeds N _N are higher than 0 (88), that is, when all the memories are filled after a certain period of time, the maximum value N _N max and the minimum value N _{N of the} engine speed N _N are reached. The difference from min is compared with a predetermined value N ₀ (89). This comparison determines whether or not n pieces of data of the engine speed N _N accumulated as described above are almost averaged, in other words, whether or not the rotation is in a stable state.

When N _N max-N _N min <N ₀ , the above n engine speeds
The average value N _N ave of N _N is calculated by the following equation (90), the average engine speed N _N ave obtained is stored in a nonvolatile memory (9
1). In addition, the previous average engine speed N
_{If N} ave is stored, it is updated to the newly obtained value.

On the other hand, in the case of the driving range of D and L in the determination of (80), the factor i is defined as 0 (92), and then the set rotational speed N _D in the D and L ranges is read out from the nonvolatile memory and averaged. It is calculated from the following formula using the engine speed N _N ave (93).

N _D = N ₁ −K · N _N ave (4) In the equation (4), N ₁ and K are constants, but can be variously changed.

Figure 6 shows N when N ₁ = 1050 rpm and K = 0.05 in equation (4).
_It shows the relationship between _D and N _N ave. For example, when the average engine speed N _N ave in the non-running range is 3000 rpm, the set speed N _{D in the} running range is 900 rpm.

After calculating the set rotational speed N _D as described above, the starting clutch 20 is creep-controlled so as to satisfy this N _D (94).
As a specific method thereof, for example, as shown in FIG. 7, the relationship between the set rotational speed N _D and the duty ratio of the start control solenoid 46 is set in advance and the set rotational speed obtained from the equation (4) is used.
A desired creep force can be generated by outputting the duty ratio corresponding to N _D to the start control solenoid 46. For example, in FIG. 7, when N _D = 750 rpm, that is, when it is desired to adjust the creep force so that the idle descent amount is 150 rpm with respect to the idle rotation speed of 900 rpm in neutral, the start control solenoid 46 has a duty ratio of 10%. Should be output.

As described above, if the engine speed is adjusted to be higher than the normal idling speed in the non-driving range, the idling speed in the driving range is adjusted accordingly,
After all, the creep force can be increased. Note that the creep force can be decreased not only by increasing the creep force but by similar control.

In the above control, only the case where the traveling range is D or L is shown, but the R range may be included. However, unlike the other travel ranges, the R range may cause trouble if the creep force is changed. Therefore, a constant creep force may always be generated in the R range.

Further, in the above control, the condition that the throttle opening is in the warm-up state and continuously opened for a certain period of time is set as a condition for distinguishing the following state from the control of the present invention.

When the driver intentionally operates the accelerator pedal in order to accelerate warm-up in the cold state immediately after start-up When the driver unintentionally or intermittently operates the accelerator pedal in the warm-up state. According to the present invention, as will be apparent from the description, the engine speed when the engine is in the non-running range state, the engine is warmed up, and the state in which the throttle opening is opened by a certain amount or more is continued for a certain amount of time or more. The transmission torque capacity of the starting clutch is controlled so as to generate the creep force according to the stored engine speed after switching to the driving range, so the creep force can be arbitrarily set by the driver's intention. it can. Further, since the control of the present invention is executed only when the above three conditions are satisfied, it is possible to prevent a change in creep force unintended by the driver and an unnecessary and frequent change in creep force.

[Brief description of drawings]

FIG. 1 is a schematic view of an example of a V-belt type continuously variable transmission to which the present invention is applied, and FIGS. 2 and 3 are specific structural views of a control valve.
FIG. 4 is a block diagram of the electronic control unit, FIG. 5 is a flowchart of an example of the control method according to the present invention, and FIG. 6 is a diagram showing the relationship between the average engine speed _N Nave and the set speed N _D. , FIG. 7 is a diagram showing the relationship between the set rotational speed N _D and the duty ratio. 1 ... Engine, 10 ... Continuously variable transmission, 20 ... Start clutch, 32 ... Output shaft, 45 ... Start control valve, 46 ... Start control solenoid, 60 ... Electronic control unit.

Claims (1)

[Claims] 1. An automatic transmission having a slip-type starting clutch capable of arbitrarily controlling a transmission torque, wherein the starting clutch is slip-controlled so as to generate a predetermined creep force during idling of the running range, in a non-running range state. , The engine speed is stored when the engine is warmed up and the throttle opening is opened for a certain period of time or more for a certain period of time. After switching to the driving range, the stored engine speed is stored. A starting clutch control method for an automatic transmission, characterized in that the transmission torque capacity of the starting clutch is controlled so as to generate a creep force according to the above.