JPH0324360A - Speed change control device of automatic transmission - Google Patents

Abstract

PURPOSE:To enable proper transmission control in accordance with road surface conditions such as a slippery surface, a curved road and a very hilly road by detecting the acceleration of a vehicle including the vehicle direction, and performing speed change control while taking account of information on the vehicle body acceleration detected. CONSTITUTION:A vehicle acceleration arithmetic means A carries out arithmetic of the acceleration of a vehicle according to a vehicle speed detected from a vehicle driving system by a vehicle speed detecting means B. a comparing means D compares the acceleration with the vehicle acceleration in its forward and backward directions detected by a vehicle acceleration detecting means C and, when the former is bigger than the latter, diagnoses that slip occurs, and selects a transmission pattern for controlling the gear to a gear position higher than the normal position by a slip transmission control means E. A holding type transmission control means F sets a transmission point mainly according to the vehicle speed when the vehicle acceleration in the transverse direction or the average value per unit time of the accerelation is big, and selects a holding type transmission pattern by which the gear is fixed in a lower gear position at less than intermediate speed. Thus stable driving performance is obtained.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a device for controlling gear changes in an automatic transmission.

<Prior Art> Conventionally, vehicles equipped with an automatic transmission with a torque converter are known to shift gears according to a preset shift pattern based on vehicle speed and throttle valve opening. (Refer to Japanese Utility Model Application Publication No. 194231/1983, etc.).

<Problems to be Solved by the Invention> In such conventional shift control, a slip state of the vehicle is detected based on the rotation difference between the driving wheel and the driven wheel, and a shift pattern is selected that controls the gear position to be higher than usual. There are some systems that control speed change by using multiple sensors, but they require multiple sensors.

Further, since the gear shift is performed independently of cornering driving, when the gear shifting is performed during cornering driving, the driving may become unstable.

The present invention has been made in view of these conventional problems, and by simply providing a means for detecting the acceleration of the vehicle, software can determine the skidding state and cornering driving state of the vehicle and adapt to these conditions. The object of the present invention is to provide a shift control device for an automatic transmission that performs stable shift control by performing controlled shift control. <Means for Solving the Problems> For this reason, the present invention, as shown by the solid line in FIG. The present invention includes a vehicle acceleration detecting means for detecting vehicle acceleration, and a speed change control means for performing speed change control in consideration of information on the detected vehicle body acceleration.

Further, as shown by the chain line in the same figure, the speed change control means includes:
vehicle acceleration calculation means for calculating the acceleration of the vehicle based on the vehicle speed detected from the vehicle drive system by the vehicle speed detection means;
The calculated vehicle acceleration is compared with the longitudinal acceleration of the vehicle detected by the vehicle acceleration detection means, and when the former is greater than the latter, it is determined that the vehicle is slipping, and the vehicle is determined to be slipping. It may be configured to include a slip shift control means that selects a shift pattern that controls a higher gear position and performs shift control.

Further, as shown by the dotted line in the figure, the speed change control means
When the lateral acceleration of the vehicle detected by the vehicle acceleration detection means is large or when the average value of the detected acceleration per time is large, the shift point is set mainly based on the vehicle speed, and when the vehicle speed is below an intermediate vehicle speed, the shift point is set. The present invention may include a hold-type shift control means that selects a hold-type shift switch that is fixedly controlled to a lower gear position and controls the shift.

<Operation> The vehicle acceleration detection means detects the acceleration of the vehicle including its direction, and the shift control means performs shift control taking into consideration information on the detected acceleration of the vehicle.

For example, when the speed change control means includes a vehicle acceleration calculation means and a slip speed change control means, the vehicle acceleration calculation means operates based on the vehicle speed detected from the vehicle drive system by the vehicle speed detection means. The acceleration of the vehicle is calculated, and the slip shift control means calculates the calculated vehicle acceleration and
Comparing the longitudinal acceleration of the vehicle detected by the vehicle acceleration detection means, and determining that the vehicle is slipping when the former is greater than the latter, and controlling the gear to a higher gear position than usual. Select a pattern and control the speed change.

In addition, when the shift control means includes a hold-type shift control means, when the lateral acceleration of the vehicle detected by the vehicle acceleration detection means is large or when the detected acceleration per time When the average value is large, the shift point is set mainly based on the vehicle speed, and a hold-type shift pattern is selected in which the shift point is set mainly based on the vehicle speed and the gear position is fixed at a lower gear position below the intermediate vehicle speed.

Example Embodiments of the present invention will be described below based on the drawings.

In FIG. 2 showing the configuration of an embodiment, the automatic transmission 1, which is composed of a torque converter and a transmission, includes a front clutch, a rear clutch, a brake hand. In order to control the working hydraulic pressure of each transmission element such as the low & reverse brake and one-way clutch, solenoid valves 2A to 2E are installed in the hydraulic pressure passages leading to these and control the working hydraulic pressure by controlling the valve duty. It is provided.

On the other hand, a throttle sensor 3 is provided which detects the opening degree of a throttle valve installed in an engine passage (not shown). In addition, a vehicle speed sensor 4 that detects vehicle speed is located near the output shaft of the transmission, and a gear position G (
A gear position sensor 5 is provided to detect the gear shift position.

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

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

The control unit 8 is configured with a built-in microcomputer, and based on the signals from each sensor,
The gear change point of the transmission is determined in consideration of the steering angle information, and the shift control is performed by controlling the opening duty of each of the solenoid valves 2A to 2E.

The above speed change control will be explained below according to the flowchart shown in FIG. In step 1 (denoted as S in the figure), the detected values of the current throttle valve opening θ, vehicle speed ■, gear position G, and vehicle acceleration α are read.

SteSob 2 calculates the acceleration α of the vehicle from the detected value of the vehicle speed V.

Calculate. Specifically, this routine is executed for a unit time ΔL
The amount of change ΔV in the vehicle speed V obtained by subtracting the vehicle speed V detected last time or a predetermined number of times n from the vehicle speed V detected this time is calculated based on the time difference ΔL between the two detected values or the predetermined number of times n. The value divided by the time in minutes n・Δt, that is,
α. It is determined as =ΔV/Δt (or ΔV/(n·Δ1)).

In step 3, a certain amount α in the longitudinal direction is calculated from the acceleration α of the vehicle detected by the acceleration sensor 6. This can be obtained as α, -α·cos β, where β is the angle formed by the direction of acceleration and the direction of travel.

In step 4, the acceleration αC of the vehicle calculated based on the detected value of the vehicle speed V (since the vehicle speed ■ is detected with respect to the traveling direction, the acceleration is also in the traveling direction, that is, the longitudinal direction) and the acceleration sensor 6 are calculated. The detected acceleration α is compared with the acceleration α calculated from the detected acceleration α.

If α0 is larger than α by a predetermined amount Δα, the actual vehicle speed is relatively small compared to the vehicle speed determined by detection from the drive system (wheel rotation), and the vehicle is slipping. It is determined that this is the case, and the process proceeds to step 5, in which flag F. Set.

In addition, in the comparison in step 4, the larger the acceleration, the
On the other hand, since the acceleration sensor 6 cannot detect very small accelerations, the conditions for comparison are as follows:
Moreover, α. If it is determined that the vehicle is slipping when the value obtained by dividing −α by the acceleration α is equal to or greater than a predetermined value, the determination accuracy will be improved.

If the judgment in step 4 is that the slip is small, the process proceeds to step 6, where the lateral acceleration α is calculated from the detected acceleration α. This is obtained as α,=α·sin β.

In step 7, it is determined whether or not to switch to a hold-type shift pattern suitable for curved road surfaces such as mountain roads based on the lateral acceleration α5 and vehicle speed (2). in particular,
First, coefficient A is searched from the map shown in FIG. 4 using acceleration α8. This has a characteristic that the acceleration α8 gradually decreases when it is greater than a predetermined value. Next, coefficient B is searched from the map shown in FIG. 5 using vehicle speed V. This decreases until the vehicle speed V reaches an intermediate vehicle speed, for example 40 km/h.
At vehicle speeds higher than that, it has the characteristic of gradually increasing.

Then, the value A-B multiplied by these coefficients A and B is compared with the set value C, and if it is less than the set value C, the process proceeds to step 8 to use the hold type shift pattern suitable for the curved road. Set flag FC. That is, basically, when the lateral acceleration α3 is large, it is desired to stop the gear shift, so the coefficient A is set small.Also, near the intermediate vehicle speed, the gear shift is most frequently performed in the normal shift pattern, so Since we want to use a shift pattern that stops shifting, coefficient B is set small.At lower vehicle speeds, there is a high probability that the gear will be in a lower gear position even in a normal shift pattern, so coefficient B is set.
For reasons such as increasing the gear position and forcibly keeping the gear position low at high vehicle speeds will increase the load on the engine, and shifting by changing the shift pattern is not desirable at high vehicle speeds. The coefficient B is increased.

Note that the predetermined value compared with A-B is set with hysteresis in order to prevent frequent shifting due to switching of shift patterns.

If it is determined in step 7 that the flag FC is not set, the process proceeds to step 9, and this time, the average value α of multiple times (for example, sampling for 1 second) of the acceleration α detected by the acceleration sensor 6 is calculated. calculate.

Then, in step 10, the average value α, is changed to a predetermined value α.
. If the answer is YES, it is determined that the vehicle is accelerated or decelerated as a result of repeating acceleration/deceleration operations on uphill and downhill roads on mountain roads, etc., and steps are taken in the same way as in the case of curved roads. Proceed to step 7 and set flag FC. N
In the case of o, the process advances to step 10 and the flag F. and flags. Reset.

Step 5. After passing through step 8 or step IO, the process proceeds to step 11, where it is determined whether the mode changeover switch 7 is in the auto mode.

If the mode is auto mode, the process advances to step 12, where it is determined whether flag F is set.

If it has been set, the process proceeds to step 12 to select a shift pattern corresponding to the slip road surface and perform shift control. In this shift pattern, in order to reduce the drive torque of the wheels and prevent slippage, the shift points are set so that the gear is shifted to a higher gear position than in the standard shift pattern, as shown in the figure. In addition, the shift control is performed by changing the target gear position searched from the shift pattern to the searched gear position G.
When the two match, the gear does not shift, and when they do not match, the gear shifts to the target gear position. The same applies to shift control using other shift patterns.

In step 12, flag F. If it is determined that the flag FC has been reset, the process proceeds to step 14, where it is determined whether or not the flag FC is set.

If it has been set, the process proceeds to step 15 to select a hold-type shift pattern suitable for curved road surfaces, mountain roads with many ups and downs, etc., and perform shift control. This shift pattern has a characteristic that the gear is fixed at a low gear position (low. or two-stage switching of second and low) below an intermediate vehicle speed. The throttle valve opening degree θ may be used for correction, or for simplicity, the shift point may be set using only the vehicle speed ■.

If the determination of the stem 14 is NO, that is, the flag F. If both flag FC and flag FC have been reset, the process proceeds to step 16, where shift control using the standard shift pattern is performed.

If it is determined in step 1l that the mode is not auto mode, the process proceeds to step 17, where shift control is performed according to each of the manually selected shift patterns.

If such shift control is performed, a shift pattern suitable for the road surface conditions can be selected and the shift control can be performed, thereby improving cornering, hill climbing, and descending performance.

Further, by providing only one acceleration sensor 6, the various speed change controls described above can be performed by software, which has a great cost advantage.

In the above embodiment, the solenoid 2 of the automatic transmission 1
The hardware such as A to 2E and the functions shown in FIG. 3 constitute the speed change control means. In particular, the function of step 2 constitutes the vehicle acceleration calculation means, and the function of step 3.4 constitutes the comparison means. The functions of step "-5. 12. 13 constitute the slip speed change control means, and step 6,
7, 9, 14. 15 functions constitute a hold type shift pattern control means.

<Effects of the Invention> As described above, according to the present invention, shift control is performed taking into account the acceleration of the vehicle, and for example, when a slip-prone road surface condition is determined based on acceleration detection information, Stable driving performance is achieved by shifting to a higher gear position than usual to suppress slipping, and when a curved road or road condition with large ups and downs is detected, the gear is fixed at a lower gear position. It is something.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIG. 2 is a block diagram showing the configuration of the present invention.
FIG. 3 is a flowchart showing the shift control routine of the embodiment of the present invention, FIG. 4 is a map of the coefficient A used in the embodiment of the invention, and FIG. 5 is the same. This is a map of coefficient B.

Claims (3)

[Claims] (1) In a shift control device for an automatic transmission that automatically switches and controls the shift position according to driving conditions, a vehicle acceleration detection means that detects the acceleration of the vehicle including the direction and information on the detected vehicle body acceleration are taken into account. 1. A speed change control device for an automatic transmission, comprising: a speed change control means for performing speed change control. (2) The speed change control means includes a vehicle acceleration calculation means that calculates the acceleration of the vehicle based on the vehicle speed detected from the vehicle drive system by the vehicle speed detection means, and a vehicle acceleration calculation means that calculates the acceleration of the vehicle based on the vehicle speed detected from the vehicle drive system by the vehicle speed detection means, and the calculated vehicle acceleration and the vehicle acceleration detection means. It compares the detected acceleration in the longitudinal direction of the vehicle, and when the former is greater than the latter, it determines that the vehicle is slipping, and selects a shift pattern that controls the gear position to be higher than normal. 2. The speed change control device for an automatic transmission according to claim 1, further comprising a slip speed change control means for controlling the slip speed change. (3) The speed change control means is configured to change the speed mainly based on the vehicle speed when the lateral acceleration of the vehicle detected by the vehicle acceleration detection means is large or when the average value per time of the detected acceleration is large. 3. The automatic transmission according to claim 1, further comprising a hold-type shift control means for controlling the shift by setting a point and selecting a hold-type shift pattern in which the gear position is fixed at a lower gear position at an intermediate vehicle speed or lower. transmission control device.