JPH0483967A - Shift control method for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a frequent shift during control of constant speed running and to provide an enough drive force by effecting a shift in a way that when constant speed running is performed through operation of a constant speed running means, a gear speed having a change gear ratio narrower than that when constant speed running is not effected is selected. CONSTITUTION:When constant speed running is controlled, the gear speed train of a forward eighth speed containing all forward gear speeds indicated on a table is set, and based on a running condition, a shift to a given gear speed selected from the gear speeds is effected. Thus, in this case, it is clear from the table that a width between the second speed and a 2.5-th speed is approximate 1.3, a width between a third speed and a 3.2-th speed is approximate 1.1, a width between a 3.2-th speed and a 3.5-th speed is approximate 1.2, and a width between a 3.5-th speed and a fourth speed is approximate 1.1. The width of a gear change ratio when constant speed running is controlled is narrower than that when constant speed running is not controlled, and further various drive forces are provided. A drive force obtained at the gear speed is a drive force suitable for running resistance at a current point of time in relation to a set car speed.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a method of controlling the speed change of an automatic transmission connected to an engine equipped with constant speed running means.

BACKGROUND ART This type of engine is configured to maintain the actual vehicle speed at the set vehicle speed by controlling the throttle opening based on the set vehicle speed and the detected vehicle speed.
In vehicles that are equipped with this type of engine and an automatic transmission, the engine's constant speed driving control and the automatic transmission's shift control are generally not particularly actively related. Shifting is carried out in accordance with the vehicle speed and throttle opening in the same way as in a normal vehicle. Therefore, for example, if the vehicle speed does not increase even if the throttle opening is increased due to large running resistance, the automatic transmission will downshift according to the shift diagram, and as a result, the driving force will increase and the vehicle speed will increase. Then you will have to perform an upshift. In other words, if the driving force that matches the running resistance at the set vehicle speed is somewhere between the driving forces obtained at the two gears,
Downshifts and upshifts as described above will occur repeatedly. If the frequency of downshifts and upshifts is high, the shift shock will be large, resulting in poor ride comfort, and if the vehicle is constantly driven in low gears,
Since the engine speed increases, problems such as worsening fuel consumption and noise arise.

Conventionally, a device for controlling an automatic transmission connected to an engine equipped with such a constant speed running means has been disclosed in Japanese Unexamined Patent Application Publication No. 1999-1-
Publication No. 208236 describes a device that changes an upshift line to a high speed side and a downshift line to a low speed side in a shift diagram that defines the shift points of an automatic transmission when traveling at a constant speed. According to this device, the vehicle speed range that the receiver has at a predetermined gear stage is expanded, making it difficult to shift gears, and so-called busy shifting, in which gear shifts occur repeatedly between two gear stages, is prevented.

Problems to be Solved by the Invention With the above-mentioned conventional device, unless the vehicle speed becomes considerably slow,
Alternatively, the downshift will not occur unless the throttle opening becomes considerably large, and the vehicle speed does not increase considerably, or the throttle opening must become considerably small.
Since no upshift occurs, busy shifting can be prevented, but since the shift line is originally set to obtain the necessary driving force, changing it to the low or high speed side will reduce the required driving force. Problems arise in that power cannot be obtained, resulting in reduced power performance or poor riding comfort. In other words, in the conventional device described above, even if the vehicle speed decreases due to insufficient driving force against running resistance, a downshift occurs. The delay becomes large, resulting in a vehicle with an impression of poor power performance. If the vehicle speed increases after downshifting, the set vehicle speed is maintained by operating the accelerator. However, when the upshift point becomes high, the engine speed remains high, forcing the vehicle to drive at a high engine speed, resulting in poor fuel efficiency.

The present invention was made against the background of the above-mentioned circumstances, and an object of the present invention is to provide a speed change control method that can prevent frequent speed changes during constant speed driving control and at the same time obtain sufficient driving force. .

Means for Solving the Problems The above-mentioned conventional devices make it difficult to shift gears at the expense of inadequate driving force, but the present invention, on the contrary, By adapting the driving force to the resistance as much as possible, shifting can be prevented. That is, the present invention provides a method for controlling the speed change of an automatic transmission connected to an engine equipped with a constant speed traveling means for maintaining the vehicle speed at a set vehicle speed, when the constant speed traveling means is operated to perform constant speed traveling. This is a method characterized by selecting a gear position with a narrower gear ratio width than when the vehicle is not traveling at a constant speed.

Function: In the method of the present invention, when the constant speed traveling means is operated to perform constant speed traveling control, the range of the gear ratio set by the automatic transmission is narrowed, and the range of the gear ratio set by the automatic transmission is more appropriate for the traveling resistance at the set vehicle speed. A gear position that can obtain a suitable driving force is selected. Therefore, since the vehicle speed does not significantly decrease or increase, frequent gear changes are not required, and quiet and fuel-efficient driving is possible.

Example Next, the method of the present invention will be explained based on examples.

An example of the method of the present invention is shown in a flowchart in FIG. 1. The automatic transmission targeted by this method is connected to an engine capable of constant speed running control, and has multiple types of engagement/disengagement patterns. FIG. 2 is a block diagram showing an example of this. That is, the automatic transmission A is connected to the engine E via the torque converter T, and the transmission control device 10 receives the throttle opening θ, vehicle speed V1 brake signal, cooling water temperature, pattern select signal, and other signals. Based on this information, the gear position to be set and the engagement/disengagement pattern for setting the gear position are selected and a signal is output to the hydraulic control device C. Furthermore, the speed change control bag [10 is connected to the engine control device 1fll. This engine control device 11 controls a throttle valve using a predetermined actuator (not shown) to maintain a set vehicle speed, and determines whether constant speed driving control is performed or not. A signal indicating this is output to the speed change control device 10.

The automatic transmission A described above includes a gear train having a plurality of types of engagement/disengagement patterns for setting a predetermined gear stage, and an example of the gear train is shown in FIG. 3. The example shown here is
It is mainly composed of three sets of single pinion type planetary gear mechanisms L2, 3, and these planetary gear mechanisms 1, 2.3
Each element in is connected as follows. That is, the carrier IC of the first planetary gear mechanism 1 and the ring gear 3R of the third planetary gear mechanism 3 are connected to rotate together, and the ring gear 2R of the second planetary gear mechanism 2
and the carrier 3C of the third planetary gear mechanism 3 are connected to rotate together.

Further, the sun gear IS of the first planetary gear mechanism 1 is connected to the carrier 2C of the second planetary gear mechanism 2 via the second clutch means 2, and the second planetary gear mechanism 2 is connected to the fourth clutch means via 4. Further, the carrier 2C of the second planetary gear mechanism 2 is connected to the sun gear 3S of the third planetary gear mechanism 3 so as to rotate together.

Note that as a connection structure for each of the above-mentioned elements, a connection structure used in general automatic transmissions such as a hollow shaft, a solid shaft, or an appropriate connecting drum can be used.

The input shaft 4 is connected to the engine E via a power transmission means (not shown) such as a torque converter or a fluid coupling, and the input shaft 4 is connected to the ring gear I of the first planetary gear mechanism 1.
A first clutch means 1 for selectively connecting the two is provided between the input shaft 4 and the first planetary gear mechanism 1.
A third clutch means 3 is provided between the sun gear IS and the sun gear IS for selectively connecting the two.

In addition, in practical use, since there are restrictions on the arrangement of each component, each clutch means Kl is set at 2°K3. It goes without saying that an appropriate intermediate member such as a connecting drum may be interposed as a connecting member to 4.

Further, as a brake means for preventing the rotation of the rotating members in the above planetary gear mechanism 1.2.3, a second brake means B2 for selectively preventing rotation of the carrier 2C of the second planetary gear mechanism 2, and a second brake means B2 for selectively preventing rotation of the carrier 2C of the second planetary gear mechanism 2; A third brake means B3 for selectively blocking the rotation of the sun gear 2S of the gear mechanism 2 is provided. In addition to the multi-plate structure, these braking means include a one-way clutch installed between the transmission case (hereinafter simply referred to as the case) 6, a band brake arranged in parallel with the one-way clutch, etc. It can be configured either in combination or in combination. In addition, in practical use, these brake means B2. Of course, an appropriate connecting member may be interposed between B3 and each element to be fixed by these brake means B2, B3 or between the case 6.

An output shaft 5 that transmits rotation to a propeller shaft and a counter gear (not shown) is connected to the ring gear 2R of the second planetary gear mechanism 2 and the carrier 3C of the third planetary gear mechanism 3, which are connected to each other. ing.

The above-mentioned automatic transmission A has five forward speeds and one reverse speed as the main speeds, and a so-called 2.5th intermediate speed is added between the second forward speed and the third speed, and 3rd and 4th forward gear
It is possible to set 8 forward gears and 1 reverse gear with two intermediate gears, so-called 3rd and 2nd gears and 35th gear, between the two speeds, and this can be shown as an operation table. As shown in Table 1.

In Table 1, the ○ mark indicates engagement, the blank space indicates release, and the * mark indicates engagement. In addition, the gear ratios of the gears shown in Table 1 are as follows: ρl = G, 45G, ρl = G, 45G, ρ
This is the value when 2=ρ3=14t15.

(This page, blank spaces below) Table 1 An example of the method of the present invention for automatic transmission A equipped with the gear train described above is as shown in the flowchart in FIG. Load driving conditions such as θ, vehicle speed, presence or absence of constant speed driving control (odd drive control), pattern select signal, and cooling water temperature. This can be done by the above-mentioned speed change control device 10, and then it is determined from the read data whether constant speed driving control is being performed, that is, autodrive operation is being performed (step 2). If the judgment result is "no", proceed to step 3, set a gear train of 5 forward gears and 1 reverse gear, and select a predetermined gear gear from among these gears based on the driving conditions. Shift to. The five forward gears selected here are 1st gear, 2nd gear, and 2nd gear shown in Table 1.
There are 3rd gear, 4th gear, and 5th gear, and the gear ratios of these gears have a relationship close to a geometric series, and the width (ratio of gear ratios) is "15" to " It is about 14".

Also, if constant speed running control is being performed and the judgment result in step 2 is "yes", proceed to step 4 and set an 8 forward gear train including all the forward gears shown in Table 1, and then proceed to step 4. The gear is shifted to a predetermined gear selected from among these gears based on the conditions. Therefore, in this case, as is clear from Table 1, the width between the 2nd speed and the 25th speed is "1".
3", and the width between 3rd gear and 32nd gear is "
The width between the 32nd speed and the 35th speed is about 1.2, and the width between the 35th and 4th speed is about 11. Compared to the case where constant speed running control is not performed, the range of the gear ratio is narrower and more diverse driving forces can be obtained.

Therefore, for example, if the driving force obtained in 3rd gear is too large for the set vehicle speed and the driving force obtained in 4th gear is insufficient, the intermediate gears, 3.2nd or 365th gear, may be used. is selected and set, and the driving force obtained at that gear is the driving force that is suitable for the set vehicle speed and the running resistance at that time, so slight excesses or deficiencies in the driving force can be dealt with by finely adjusting the throttle opening. and maintain the set speed. As a result, there is no need to shift gears due to a drop in driving force or a large variation in vehicle speed caused by the drop in driving force, so that so-called busy shifts can be prevented and sufficient driving force can be obtained.

Note that if constant speed driving control is not performed, the range of gear ratios will increase, but if gear changes occur frequently or if driving force is insufficient, the vehicle speed may be adjusted artificially. I almost never experience a busy shift or feel a lack of driving force. Furthermore, since shifting according to a gear stage with a narrow gear ratio width is not performed when the vehicle speed is artificially adjusted, it is possible to prevent a busy shift in which a shift occurs every time the accelerator pedal is slightly adjusted.

In the above embodiment, an automatic transmission equipped with a gear train shown in FIG. Targeted automatic transmissions equipped with a gear train that can select between gears with a wide gear ratio range and between gears with a narrow gear ratio range. Examples of automatic transmissions equipped with this type of gear train include one in which any of the frictional engagement means shown in FIG. 3 includes a one-way clutch, and The already proposed Japanese Patent Application No. 1-185151, Japanese Patent Application No. 1-185152, Japanese Patent Application No. 1-186991, Japanese Patent Application No. 1-186992, Japanese Patent Application No. 1-205478,
Examples include those having various configurations described in specifications and drawings such as Japanese Patent Application No. 1-280957.

Effects of the Invention As is clear from the above explanation, according to the method of the present invention, during constant speed driving control in which the vehicle speed is controlled to maintain a constant vehicle speed while driving, the driving resistance at the set vehicle speed is improved. Since the gear position is set to a position where an appropriate driving force can be obtained, it is possible to avoid insufficient driving force, fluctuations in vehicle speed due to the lack of driving force, and frequent gear changes.

[Brief explanation of drawings]

Fig. 1 is a flowchart for explaining an example of the method of the present invention, Fig. 2 is a block diagram showing the basic configuration of an automatic transmission targeted by this invention, and Fig. 3 is a skeleton showing an example of the gear train. It is a diagram. 1.2.3...Planetary gear mechanism, 4...Input shaft, 5
...output shaft, 10...speed change control device, 11...
・Engine control device, A... automatic transmission, C...
・Hydraulic control device, E...Engine. Figure 1

Claims (1)

[Claims of Claims] When controlling the speed change of an automatic transmission connected to an engine that is equipped with a constant speed running means for maintaining the vehicle speed at a set vehicle speed, when the constant speed running means is operated to perform constant speed running. A speed change control method for an automatic transmission, characterized in that the speed change is performed by selecting a gear position having a narrower gear ratio range than when constant speed driving is not performed.