JP2561151B2 - Transmission control device for automatic transmission - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for controlling a shift of an automatic transmission.

<Prior Art> A vehicle equipped with an automatic transmission with a torque converter is conventionally known to perform gear shifting according to a preset gear shifting pattern based on a vehicle speed and a throttle valve opening. (See Japanese Utility Model Publication No. 62-194231, etc.).

<Problems to be Solved by the Invention> In such a conventional shift control, a slip state of a vehicle is detected based on a rotation difference between a driving wheel and a driven wheel, and a shift pattern for controlling a gear position higher than usual is selected. Although there is one that performs gear shift control, it is necessary to provide a plurality of sensors.

Further, since the gear shift is performed regardless of the cornering operation, traveling may be unstable when the gear shift is performed during the cornering operation.

The present invention has been made in view of the above conventional problems, and only by providing a means for detecting the acceleration of the vehicle, the slip state and the cornering operation state of the vehicle are determined by software, and the state is adapted to these states. It is an object of the present invention to provide a shift control device for an automatic transmission, which performs stable shift control by performing the above shift control.

<Means for Solving the Problems> Therefore, according to the present invention, as shown by a solid line in FIG. 1, in the shift control device of the automatic transmission for automatically controlling the shift position according to the driving condition, the acceleration of the vehicle is changed in the direction. Vehicle acceleration detection means for detecting the vehicle speed, vehicle speed detection means for detecting the vehicle speed from the vehicle drive system, and vehicle acceleration calculation means for calculating the longitudinal acceleration of the vehicle based on the vehicle speed detected by the vehicle speed detection means. Comparing a value obtained by dividing a difference between the calculated longitudinal acceleration of the vehicle and the longitudinal acceleration of the vehicle detected by the vehicle acceleration detecting means or dividing the calculated acceleration by the calculated vehicle acceleration with a reference value, When the value of is larger than the reference value, it is judged that the vehicle is in a road surface condition in which it is likely to slip, and a shift pattern to control to a gear position higher than usual is selected and controlled. It is characterized in that the control means and the control means are included.

<Operation> The vehicle acceleration detecting means detects the acceleration of the vehicle including its direction, while the vehicle acceleration calculating means calculates the longitudinal acceleration of the vehicle based on the vehicle speed detected by the vehicle speed detecting means.

Then, the slip shift control means divides the difference between the calculated longitudinal acceleration of the vehicle and the detected longitudinal acceleration of the vehicle by the detected or calculated vehicle speed acceleration,
This value is compared with the reference value, and when the former value is equal to or greater than the reference value, it is determined that the vehicle is in a road surface condition in which the vehicle is likely to slip, and the gear position is controlled to a higher gear position than usual.

<Example> Below, the Example of this invention is described based on drawing.

Referring to FIG. 2 showing the configuration of an embodiment, an automatic transmission 1 including a torque converter and a transmission.
In order to control the hydraulic pressure of each transmission element such as front clutch, rear clutch, brake band, low & reverse brake, one-way clutch,
Solenoid valves 2A to 2E are provided which are interposed in hydraulic passages guided by these and control the operating hydraulic pressure by controlling the valve opening duty thereof.

On the other hand, a throttle sensor 3 for detecting the opening of a throttle valve provided in an engine passage (not shown) is provided. A vehicle speed sensor 4 for detecting a vehicle speed V is provided near the output shaft of the transmission, and a gear position G is provided for the transmission.
A gear position sensor 5 for detecting (shift position) is provided.

Further, an acceleration sensor 6 as an acceleration detecting means for detecting the acceleration of the vehicle including the direction, an auto mode for automatically switching a plurality of shift patterns as described later, and a manual mode for setting a selected shift pattern. A mode selector switch 7 for switching between and is provided.

Each signal detected by these is input to the control unit 8.

The control unit 8 is configured by incorporating a microcomputer, determines the gear shift point of the transmission in consideration of the steering angle information based on the signals from the respective sensors, and opens the solenoid valves 2A to 2E. Shift control is performed by controlling the duty.

The shift control will be described below with reference to the flowchart shown in FIG.

In step (denoted as S in the figure) 1, the detected values of the current throttle valve opening θ, vehicle speed V, gear position G, and vehicle acceleration α are read.

In step 2, the vehicle acceleration α is calculated from the detected value of the vehicle speed V.
Calculate _c . Specifically, this routine is executed in unit time Δ
The change amount ΔV of the vehicle speed V, which is obtained by subtracting the vehicle speed V detected before or a predetermined number of times n from the vehicle speed V detected this time, is performed every t, and the time difference Δt between the two detection values or the predetermined number of times. The value is divided by the time n · Δt for n minutes, that is, α _c = ΔV / Δt (or ΔV / (n · Δt)).

In step 3, the longitudinal component α _f is calculated from the vehicle acceleration α detected by the acceleration sensor 6. this is,
If the angle between the acceleration direction and the traveling direction is β, α _f
= Α ・ cos β

In step 4, the acceleration α _{c of} the vehicle speed obtained by calculation based on the detected value of the vehicle speed V (the acceleration is also the traveling direction, that is, the front-rear direction because the vehicle speed V is detected in the traveling direction), and the acceleration sensor 6 A value (α _c −α _f ) / α _f obtained by dividing the difference (α _c −α _f ) from the acceleration α _f obtained from the acceleration α detected by α _f by α _f is compared with the reference value Δα. Alternatively, (α _c −α _f ) / α _c may be compared with Δα.

Then, (α _c −α _f ) / α _f or (α _c / α _f ) / α
_{When c} is equal to or greater than Δα, the vehicle is slipping because the actual vehicle speed is relatively small with respect to the vehicle speed detected from the drive system (wheel rotation), and the slipping with respect to the magnitude of the acceleration is caused. It is determined that the road surface condition is such that the ratio of the magnitudes of the values is greater than a predetermined value and slip is likely to occur, and a flag F _s for using a shift pattern for controlling to a gear position higher than usual which is suitable for the road surface condition is set. .

As described above, if the configuration is such that the slipperiness of the road surface is determined based on the ratio of the magnitude of slip to the magnitude of acceleration, the determination accuracy is improved.

When the determination in step 4 is that the slip is small, the process proceeds to step 6, and this time, the lateral acceleration α _s is calculated from the detected acceleration α. This is obtained as α _s = α · sin β.

In step 7, based on the lateral acceleration α _s and the vehicle speed V, it is determined whether or not to switch to the hold-type gear shift pattern suitable for a curved road surface such as a mountain road. Specifically, first, the coefficient A is retrieved from the map shown in FIG. 4 by the acceleration α _s . This has a characteristic that it gradually decreases when the acceleration α _s is larger than a predetermined value. Next, the coefficient B is retrieved from the map shown in FIG. 5 by the vehicle speed V. This is the vehicle speed V
Has a characteristic that it decreases until reaching an intermediate vehicle speed, for example, 40 km / h, and conversely increases at a vehicle speed V higher than that. And
The values A and B obtained by multiplying these coefficients A and B are compared with the set value C. If the set value C or less, the process proceeds to step 8 and a flag for using the hold type shift pattern adapted to the curved road. Set F _c . That is, basically, when the lateral acceleration α _s is large, it is desired to stop the shift, so the coefficient A is made small, and in the vicinity of the intermediate vehicle speed, the shift is most frequently performed in the normal shift pattern. Since the shift pattern for stopping the shift is also desired, the coefficient B is set to a small value. As a result, the probability of being in the low gear position is high even in the normal shift pattern on the low vehicle speed side. The coefficient B is increased because the load on the engine is increased if the gear position is kept low and that shifting is performed by switching the shift pattern is not preferable on the high vehicle speed side.

The predetermined value to be compared with A and B is set with a hysteresis so as to prevent frequent shifts due to switching of shift patterns.

When it is determined in step 7 that the flag F _c is not set, the process proceeds to step 9, and this time, an average value α _{m of} a plurality of times of acceleration α detected by the acceleration sensor 6 (for example, one second sampling). Is calculated.

Then, in step 10, the average value α _m is the predetermined value α _mo
If YES, it is determined that the vehicle is accelerated / decelerated as a result of repeated acceleration / deceleration operations on an uphill and a downhill on a mountain road. Go to 7 and set the flag F _c . If NO, the process proceeds to step 10 to reset the flag F _s and the flag _c .

After passing through step 5, step 8 or step 10, the process proceeds to step 11, and it is determined whether the mode changeover switch 7 is in the automatic mode.

Then, in the case of the automatic mode, the process proceeds to step 12 and it is determined whether or not the flag F _s is set.

If it is set, the routine proceeds to step 12, where a shift pattern corresponding to the slip road surface is selected and shift control is performed. In this shift pattern, the shift point is set so that the gear position is shifted to a higher gear position compared to the standard shift pattern as shown in the figure in order to reduce the driving torque of the wheels and suppress slip. Note that the gear shift control is performed by the gear position G searched for the target gear position searched from the gear shift pattern.
Compared with the above, when the two match, the gear is not shifted, and when they do not match, the gear is shifted to the target gear position. The same applies to shift control with other shift patterns.

When it is determined in step 12 that the flag F _s is reset, the process proceeds to step 14 and it is determined whether the flag F _c is set.

If it is set, the process proceeds to step 15 to select a hold type shift pattern suitable for a curved road surface or a mountain road with many ups and downs, and shift control is performed. This shift pattern has a characteristic that the gear position is fixed at a low gear position (low or second / low two-stage switching) at an intermediate vehicle speed or lower. The throttle valve opening θ may be used for correction, or for simplification, the shift point may be set only by the vehicle speed V.

When the determination in step 14 is NO, that is, when both the flag F _s and the flag F _c are reset, the process proceeds to step 16, and shift control using the standard shift pattern is performed.

When it is determined in step 11 that the automatic mode is not set, the process proceeds to step 17, and shift control according to each manually selected shift pattern is performed.

If such a shift control is performed, a shift pattern suitable for the condition of the road surface can be selected and the shift control can be performed.
Improves cornering, climbing and descending performance.

Further, by providing only one acceleration sensor 6, the various shift control can be performed by software, and the cost merit is large.

In the above embodiment, the function of step 2 constitutes vehicle acceleration calculation means, the functions of steps 3 and 4 constitute comparison means, and the functions of steps 5, 12 and 13 constitute slip shift control means. The functions of steps 6, 7, 9, 14, and 15 constitute the hold type shift pattern control means.

<Effects of the Invention> As described above, according to the present invention, a road surface state in which slippage is likely to occur is determined based on a value obtained by dividing the difference between the acceleration detected from the drive system of the vehicle caused by slip and the actual acceleration by the acceleration. In this case, the gear is shifted to a higher gear position than usual to suppress slip, and when it is determined that the vehicle is on a curved road or a road surface with a large ups and downs, it is fixed at a low gear position to stabilize the operation. It is possible to obtain good running performance.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIG. 2 is
FIG. 3 is a diagram showing a configuration of an embodiment of the present invention, FIG. 3 is a flowchart showing a shift control routine of the same embodiment, FIG. 4 is a map of a coefficient A used in the same embodiment, and FIG. It is a map of B. 1 ... Automatic transmission, 2A-2E ... Solenoid valve, 3 ...
... Throttle sensor, 4 ... Vehicle speed sensor, 5 ... Gear position sensor, 6 ... Acceleration sensor, 8 ... Control unit

Claims (1)

(57) [Claims] 1. A shift control device for an automatic transmission which automatically controls shift positions according to operating conditions, and a vehicle acceleration detecting means for detecting acceleration of a vehicle including a direction, and a vehicle speed from a vehicle drive system. Vehicle speed detecting means, vehicle acceleration calculating means for calculating the longitudinal acceleration of the vehicle based on the vehicle speed detected by the vehicle speed detecting means, the calculated longitudinal acceleration of the vehicle, and the vehicle acceleration detecting means The difference between the longitudinal acceleration of the vehicle detected and the value obtained by dividing by the calculated vehicle acceleration is compared with the reference value, and when the former value is larger than the reference value, the vehicle is likely to slip in road conditions. It is judged that there is such a change, and a slip shift control means for controlling a shift by selecting a shift pattern for controlling to a gear position higher than usual, and an automatic shift characterized by the following: Machine of the shift control device.