JPS61189354A - Controlling method of automatic speed changing gears of vehicle - Google Patents

Abstract

PURPOSE:To prevent deterioration of ATF (oil used in automatic speed changing gears) by varying gear shift pattern for the purpose of easy attainment of gear shift to lower speeds and by reducing a difference between revolutional speeds when ATF is overheated. CONSTITUTION:An electronic controller 20 changes gear shifting pattern from a D range pattern to a high speed gear shifting pattern to control normal gear shift control in accordance with the high speed gear shifting pattern. The controller also controls speed changing gears in accordance with signals from a valve opening sensor 14 and a car speed sensor 18. The speed range of a second speed gear which is used for low speed running will therefore be widened with respect to car speed so that the gear shift to second speed may be attained easily. A difference between revolutional speeds of input and output shafts 4 and 8 of a torque converter 2 is therefore reduced, hence preventing excessive increase in temperature of ATF. Deterioration of ATF can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to an improvement in a vehicle automatic transmission equipped with a turbo fluid coupling such as a torque converter.

[Conventional technology]

In general, a vehicle's climbing capacity is determined by its weight and traction force, but when combined with a high-torque engine, it can generate a large traction force, so even if the transmission is geared for relatively high speeds. His pitching ability will increase.

On the other hand, in the case of automatic transmissions equipped with a torque converter, the difference in rotational speed between input and output times of the torque converter increases as the load increases (the slope of the slope increases).

Furthermore, since the smaller the gear ratio (higher speed gear), the higher the temperature increases, there is a problem in that the temperature of the automatic transmission oil (hereinafter referred to as ATF) increases due to the increase in the amount of heat generated, and the ATF deteriorates accordingly.

In order to resolve the above problem, it would be possible to set a shift pattern that always uses a low gear when the load is relatively heavy, but this would not only worsen fuel efficiency but also reduce engine speed. Since the number is high, there are problems such as disadvantages in terms of noise.

In response, automatic transmissions in which the shift pattern can be changed have been proposed in Japanese Patent Publication No. 47-36284, Japanese Patent Publication No. 48-209, etc.; This is done by detecting the ON/OFF state of a switch, the acceleration/deceleration state of the vehicle, etc., and is not effective in preventing excessive temperature rise of the ATF due to an increase in the rotational speed difference between the input and output shafts of the torque converter. It is something.

[Structure of the invention]

The present invention has been proposed in view of the above, and is connected to the output shaft of a turbo fluid coupling, and selectively changes one of a plurality of forward gears depending on vehicle speed and engine load. In the automatic transmission for a vehicle configured to achieve the above, a gear stage for a lower speed among the plurality of gear stages is selected according to a value of a rotational speed difference or a rotational speed ratio between the input and output shafts of the turbo fluid coupling. The gist of the present invention is to provide a control method for an automatic transmission for a vehicle, which is characterized by changing a shift pattern so that the following is easily achieved.

〔Effect of the invention〕

According to the above configuration, the shift pattern is changed so that a lower speed gear is more easily achieved in accordance with the value of the rotational speed difference or rotational speed ratio between the input and output shafts of a turbo fluid coupling such as a torque converter. In particular, when the above-mentioned rotational speed difference becomes large and the ATF is likely to overheat, the above-mentioned rotational speed difference is reduced by changing the gear stage to a lower speed, and the AT
This prevents an excessive rise in the temperature of F and prevents the accompanying deterioration of the ATF.

Also, as a result, a variable shift pattern can be obtained.

A lower gear is achieved only when necessary (when the load increases, such as when the driver is off the pitch), and drivability can be improved without deteriorating fuel efficiency.

[Practical example]

An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 5.

In FIG. 1, a torque converter 2 is connected to an engine 6 via an input shaft 4 and to a gear type automatic transmission mechanism 10 via an output shaft 8. Same transmission mechanism 1
0 is from the valve opening sensor 14 that detects the opening of the throttle valve 12 installed in the intake passage of the engine B and the vehicle speed sensor 18 that detects the rotational speed of the drive shaft 160 of the transmission mechanism 10, that is, the vehicle speed. It is controlled via an electric/hydraulic gear shift mechanism 22 by an electronic control device 20 that issues a gear shift signal in response to a signal, and is controlled from 6 to 4 depending on the shift signal.
One of the forward gears is achieved, and their structure and operation are disclosed in Japanese Patent Laid-Open No. 57-101.
No. 152, JP-A No. 58-37569, JP-A No. 48-2
No. 0348 or U.S. Pat. No. 3,448,640, etc., and the present invention is for vehicles in which a plurality of gears, such as those described in the above publications, are electrically controlled. It is applicable to automatic transmissions.

With the above configuration, each gear stage is normally achieved according to the normal shift pattern (hereinafter referred to as D range pattern) as shown in FIG. In addition, Figure 2 fa
A solid line indicates an upshift, and a dashed line indicates a downshift.

The electric control device 20 receives signals from a rotation sensor 24 that detects the rotation speed of the input shaft 40 and a rotation sensor 26 that detects the rotation speed of the output shaft 80.
The input shaft 40 is activated by signals from both rotation sensors 24 and 26.
The rotation speed is set to a predetermined value (which varies depending on the vehicle speed at that time, for example 600 to 110) than the output shaft 60 rotation speed.
As the vehicle speed increases between 00 rpm (a value is set to decrease), the electronic control unit 20 changes from the D range pattern shown in FIG. 2(a) to the high speed shift pattern shown in FIG. 2(bl). (hereinafter referred to as SC pattern), and according to the same SC pattern, the gear position is controlled based on the signals from the valve opening sensor 14 and the vehicle speed sensor 18 in the same way as normal shift control. The range of the second gear, which is a gear gear for lower speeds, becomes wider relative to the vehicle speed.In other words, the second gear gear is easier to achieve.For this reason, the input/output shaft 4 of the torque converter 2
．． The difference in rotational speed between the two rotational speeds becomes smaller, preventing an excessive rise in temperature of the ATF, and also improves drivability since this is an operating state where the load is large.

Thereafter, when the driving state of the vehicle satisfies conditions such as the vehicle speed becoming equal to or higher than a predetermined value, the shift pattern is switched again from the SC pattern to the D range pattern and one normal shift control is performed.

A method for achieving the above control will be explained in detail according to the flowchart shown in FIG. The flowchart starts at the same time as the engine of the vehicle is started and is repeatedly executed at a cycle of, for example, 0.1 seconds. After the program starts, in step (1), the rotation speed NP from the rotation sensor 24 + the rotation speed NT from the rotation sensor 26, and the throttle valve opening θT from the valve opening sensor 14.
, the vehicle speed V from the vehicle speed sensor 18, the position of a shift lever (not shown) for operating a conventionally known manual valve installed in the hydraulic circuit, the gear position achieved by the transmission mechanism 10, etc. are detected, and the step In (2), it is determined whether the shift lever position is in the D range or not. If it is outside the D range, the counter C1+CZe used to measure a predetermined time described later in step (3)
is reset to zero, and in step (4), a shift pattern corresponding to the position (range) of the shift lever is read out from the memory circuit and set, and the shift pattern set in step (5) is read in step (1). It is checked from the valve opening degree θT and the vehicle speed V whether or not it is necessary to change the gear position, and in step (6) it is determined whether or not a gear change is necessary. In step (8), the rotational speed difference between the input shaft 4 and the output shaft 8 of the torque converter 20 is changed according to the vehicle speed V (for example, between 600 and 1 ooorps). The setting value N1 (which decreases as the vehicle speed increases) is calculated.If the shift is not determined in step (6) above, step (8) is executed next.Then, in step (9), the rotation It is determined whether the difference between the speed NP and the rotational speed NT is greater than the above N, and if it is larger, 1 is added to the counter C2 in step (10), and 1 is added to the counter C3 in step (11). Add and exit the program.

If the difference between NP and NT is smaller than N1, step (11) is executed and the program ends. In addition.

When the shift lever is in the neutral, reverse, or parking position, the gear position corresponding to the lever position is achieved, so the control will be explained from the flowchart in Figure 3 to avoid complications. It is omitted.

If it is determined in step (2) above that the shift lever position is in the D position, step (12)
The set state of the SC pattern flag indicating whether or not to select a pattern is determined, and if it is not set (reset state), the vehicle speed V is determined to be equal to or higher than a predetermined VIIh (for example, 60 to 80 Wh) in step (13). If it is not equal to or higher than V□lh, then in step (14) the counter C2 changes depending on various conditions such as the performance of the engine 6 and torque converter 2, the gear ratio setting of the transmission mechanism 10, and the weight of the vehicle. A predetermined time cH seconds (for example, 1
6 seconds) was measured () - One charge is repeatedly executed at a cycle of 01 seconds, so if cH is set to 16 seconds, for example, whether or not step (10) has been executed 160 times. If it is not measured, step (
In step 15), check whether the counter C8 has measured a predetermined time cT seconds determined in the same manner as in the above CH (for example, if it is set to 22 seconds, check whether the step (11) has been executed 220 times or not. If the vehicle speed V is not measured, the vehicle speed V is determined to be the predetermined vehicle speed V21apy'h in step (16).
(for example, 5 to 81 @/h) or less, and
If the vehicle speed V is not less than V2A21/h, then in step (17) the vehicle speed V is set to a predetermined vehicle speed v3Wh (for example, 65 to 85#/h).
) or more, and if it is not more than 'V31an/h, then go to step (18) to judge the cent state of the SC pattern flag again, and if it is in the reset state, step (
At step 19), the D range pattern is read out from the memory circuit and set, and thereafter the control from step (5) onward is performed using the same D range pattern. Also, step (18)
If it is determined that it is in the cent state, step (
At step 20), the SC pattern is read out from the memory circuit and set, and thereafter the speed change control is performed using the same SC pattern.

On the other hand, if it is determined in step (14) that the counter C2 has measured the predetermined time C8 seconds, step (21)
Set the SC pattern flag in step (22).
Reset each counter C,,C,,C,to zero with,.

Thereafter, the program after step (16) is executed, and in step (15) the vehicle speed V is set to a predetermined vehicle speed vI.
k1! If it is determined that it is equal to or more than V/h, or if it is determined in step (15) that Curran/C has measured the predetermined time CT seconds, the processes from step (22) are executed.

Further, in step (16), the vehicle speed V is set to a predetermined speed Vz l
If it is determined that the speed is below ap/h, or if it is determined in step (17) that the same vehicle type V is above the predetermined speed Vslyy'h,
At step (23), the SC pattern flag is reset and each counter C1, C2, C3 is reset to zero.

Thereafter, the processing from step (19) onwards is performed.

On the other hand, if it is determined in step (12) that the SC pattern flag has been set, it is determined in step (24) whether or not the transmission mechanism 10 has achieved the third gear. If so, 1 is added to the counter C□ in step (25), and in step (26) it is determined whether or not the counter C0 has measured a predetermined time C6 seconds (for example, 6 seconds), and whether or not the time has been measured is determined. If so, step (25) above
After that, if the measurement has not been performed, the above step (16)
) and subsequent programs are executed. On the other hand, if it is determined in step (24) that the 6th gear has not been achieved, the counter C1 is reset to zero in step (27), and the program from step (16) onwards is executed. Ru.

In the above example.

■ The rotational speed difference NP-NT of torque converter 2 The rotational speed difference setting value N is larger.

■ Vehicle speed V becomes vl! Iy′h or less The above states ■ and ■ last for C seconds during cT seconds.

It is configured to shift from the D range pattern to the SC pattern when . That is, the 0 term detects a state in which the ATF is likely to be overheated, and when the 0 term continues for a predetermined period of time, it is assumed that the temperature of the ATF has increased, and the pattern is shifted to the SC pattern. Note that the 0 term is set to prevent deterioration of drivability due to deterioration of fuel efficiency and generation of a large shift shock that the driver did not intend when shifting to the SC pattern at a high vehicle speed. Therefore, when all of the conditions shown in items 0 to 0 above are satisfied, the gear stage is set to 2nd speed, which reduces the rotational speed difference NP-NT, resulting in an excessive rise in the ATF temperature and the accompanying increase in the ATF temperature. In addition to being able to prevent deterioration, the above-mentioned item 00 can suppress excessively frequent transitions from the D range pattern to the SC pattern, and furthermore, it is possible to prevent deterioration of fuel efficiency and drivability.

Note that if the value of VzJaIV'h is set high, an SC pattern will be obtained over the vehicle's low speed range to high speed range, and if it is set low, an SC pattern will be obtained only in the vehicle's low speed range. sporty car,
If you set it according to your vehicle (such as a family car), you can get a desirable driving feeling.

Also, the SC pattern.

■ 6th gear is achieved for C8 seconds or more even though the SC pattern flag is set.

■ Vehicle speed V becomes less than v2□h.

■ Vehicle speed V becomes more than v, 1aIV/h.

It is configured to be canceled if at least one of the conditions is met. In other words, the 0 term detects that the driver is not requesting a large pitching ability (output torque) from the vehicle even though it is shifting to the SC range,
The 0 item ensures that the KD range pattern is set when the vehicle starts again after coming to a stop or a near-stop state, so driving at high speeds with the 0 item SC pattern reduces fuel efficiency and reduces engine speed. This is a condition to prevent an increase in noise due to high rotation. Therefore, even though the temperature of the ATF has sufficiently decreased, the SC range is maintained for an extremely long time, and there is an effect that fuel efficiency does not deteriorate.

In the above embodiment, the shift between the third gear and the second gear has been described, but the present invention can be applied to the shift between the fourth gear and the third gear. Needless to say, substantially the same effect can be achieved even when applied to gear shifting.

Further, in the above embodiment, the SC pattern is configured to be set according to the rotational speed difference between the input and output shafts of the torque converter, but it may be configured to be controlled according to the rotational speed ratio of the input and output shafts. It is something.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing the configuration of an embodiment of the present invention, FIG. 2 is an operation explanatory diagram showing a conventional shift pattern and a shift pattern of the above embodiment, and FIG. 3 is a program applied to the above embodiment. FIG. 2...Torque converter 10...Transmission mechanism 18.
...Vehicle speed sensor 4...Input shaft 12...Suit torque valve 20...Electronic control device 6...Engine
14...Valve opening -t! Sensor 22...Electric/hydraulic gear change mechanism 8...Output shaft 1
6... Drive shaft 24.26... Vehicle speed sensor

Claims (1)

[Claims] In a vehicle automatic transmission connected to an output shaft of a turbo fluid coupling and configured to selectively achieve one of a plurality of forward gears depending on vehicle speed and engine load, The shift pattern is changed so that a lower speed gear among the plurality of gears is more easily achieved in accordance with the value of the rotational speed difference or rotational speed ratio between the input and output shafts of the turbo fluid coupling. Characteristic control method for automatic transmission for vehicles