JPH0429667A - Automatic speed change control device for vehicle with torque converter - Google Patents

Abstract

PURPOSE:To surely change a speed relating to a change of engine performance so as to perform a smooth speed change by using drive torque and a car speed at this time and indexing speed change ratio at this time from prepared drive torque and a speed change ratio switching data of the car speed to drive-control a switching drive means. CONSTITUTION:A controller 21 reads drive torque, obtained by a drive torque calculating routine, while calculating a car speed at this time based on a detection signal from a car speed sensor 24. Next, a speed change region at this time is indexed by using the car speed at this time and the drive toque from a data map. Successively, the indexed speed change region is judged for whether it is transferred or not to a region different from the preceding speed change region. In the case of the region transferred, the controller 21 excitation-controls 1-speed, 3-speed solenoids SL1, SL3 so as to obtain speed change ratio of the speed change region. Oppositely in the case of no change, a speed change routine is newly executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic transmission control device that controls a transmission mounted on a vehicle.

[Prior Art] As shown in FIG. 6, a vehicle equipped with a torque converter has a configuration in which an engine 1 is connected to a torque converter 2, and the output of the converter 2 is transmitted to drive wheels 5 via a transmission 3 and a differential gear 4. It has become. The gear ratio of the transmission 3 is controlled by the seventh
As shown in the figure, this is carried out by a controller consisting of a microcomputer. The controller receives detection signals from a vehicle speed sensor that detects the actual speed of the vehicle and an accelerator opening sensor that detects the amount of operation of the accelerator pedal (accelerator opening). Then, the controller determines whether or not to change the gear ratio based on map data prepared in advance as a gear shift map shown in FIG. 7 from the vehicle speed and accelerator opening at that time. In other words, the solid line L1 is the boundary where the gear ratio changes from 1st to 2nd gear, the solid line L2 is the boundary where the gear ratio is changed from 2nd to 3rd, and the broken line L3 is the boundary where the gear ratio is changed from 3rd to 2nd. The broken line L4 indicates the boundary where the gear ratio is changed from 2nd speed to 1st speed. Then, the vehicle speed and accelerator opening at that time are these boundary lines L1~
When L4 is exceeded, the gear ratio is changed to the gear ratio on the side beyond that.

When the change of the gear ratio is determined, the controller drives the gear change actuator that switches the gear ratio of the transmission 3, and changes the transmission 3 via the actuator. It is designed to switch to a suitable gear ratio.

By the way, it is desirable that the speed change map shown in FIG. 7, which determines the change of the speed ratio, be such that smooth speed changes are performed and that no change in driving force occurs before and after the speed change. For this purpose, a driving performance curve is created and a shift map is determined from the driving performance curve. To be more specific, as shown in FIG. 8, the driving performance curve is obtained by determining the driving force versus vehicle speed for each gear ratio of 1st to 3rd speeds while keeping the accelerator opening constant. And the driving performance white line La of ■ speed and 2nd speed.

Intersection A of Lb and driving performance curves Lb for 2nd and 3rd speeds.

Find the intersection B of Lc. That is, the vehicle speed at the intersection A means that even if the vehicle speed is changed from 1st speed to 2nd speed at this accelerator opening degree, the driving force is the same, so the changeover is smooth. Furthermore, the vehicle speed at the intersection point B means that even if the vehicle speed is changed from 2nd speed to 3rd speed at this accelerator opening degree, the driving force is the same, so the changeover is smooth. And these intersection points A and B
is the switching point of the gear ratio based on the accelerator opening and vehicle speed at that time, and below, by changing the accelerator opening and finding the driving performance curve as above for each accelerator opening, the shifting map shown in Fig. 7 is obtained. There is.

Also, at this time, the running performance curve is obtained from the engine output characteristics and torque converter performance shown in FIG. 9, and the output torque of the engine 1 at the intersections A and B comes close to the zero point of the engine output torque characteristics. Therefore, when a shift is performed using the above-mentioned shift map, the shift is performed at the 0 point.

[Problems to be Solved by the Invention] However, the output torque characteristic is such that the output torque rapidly decreases from a certain rotation speed due to the governor device, and the zero point has almost no margin for increasing the engine rotation speed. . Therefore, when the output torque characteristics change as shown by the broken line due to the engine 1 being cold or aging,
The engine speed no longer increases to the speed corresponding to the 0 point.

As a result, the problem arises that the vehicle speed does not increase to the shift point, making it impossible to shift.

In order to avoid this, if the 0 point is set at C1, which has a low rotational speed, the intersection points A and B become points AI and Bl, respectively, on the driving performance curve, and the driving force after shifting decreases. Therefore, if the gear ratio is upshifted while pitching, the driving force will decrease, the vehicle speed will decrease, and the gear will shift down, resulting in repeated upshifts and downshifts, resulting in the problem that smooth pitching will not be possible. arise.

This invention was made to solve the above-mentioned problems, and its purpose is to be able to reliably shift gears against performance changes such as changes in engine temperature and aging, and to perform smooth gear shifts. An object of the present invention is to provide an automatic transmission control device for a vehicle equipped with a torque converter.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a system in which the gear ratio of a transmission that is drivingly connected to an engine through a torque converter is controlled to be switched based on the switching drive of a switching drive means. In an automatic transmission control device for a vehicle equipped with a torque converter, an engine rotation speed detection means for detecting the engine rotation speed, a turbine rotation speed detection means for detecting the turbine rotation speed of the torque converter, and a vehicle speed detection means for detecting the vehicle speed. and speed ratio calculation means for calculating the speed ratio of the torque converter based on the engine rotation speed detected by the engine rotation speed detection means and the turbine rotation speed detected by the turbine rotation speed detection means, and data prepared in advance from the speed ratio. output torque calculating means for determining the capacity and torque ratio of the torque converter with respect to the speed ratio, and calculating the output torque of the torque converter using the capacity, torque ratio, and the engine speed; and the output torque and the transmission at that time. a drive torque calculating means for calculating a drive torque based on a gear ratio; and a drive torque calculation means that calculates a gear ratio at that time from gear ratio switching data of a transmission for the drive torque and vehicle speed prepared in advance using the drive torque and the vehicle speed at that time, and the switching drive. The gist of the present invention is an automatic transmission control device for a vehicle equipped with a torque converter, which is equipped with a transmission ratio calculation control means for driving and controlling the transmission means.

[Operation] The speed ratio calculation means calculates the speed ratio of the torque converter based on the engine rotation speed and turbine rotation speed determined from the engine rotation speed detection means and the turbine rotation speed detection means.

The output torque calculation means calculates the capacity and torque ratio of the torque converter for the speed ratio using data prepared in advance from the speed ratio, first calculates the input torque of the torque converter from the capacity and the engine rotation speed, and calculates the input torque of the torque converter from the capacity and engine speed. The output torque of the torque converter is calculated using the torque and the torque ratio.

The drive torque calculation means calculates the drive torque using the output torque and the gear ratio of the transmission at that time.

The gear ratio calculation control means uses the drive torque and the vehicle speed obtained from the vehicle speed detection means at that time to determine the gear ratio at that time from the gear ratio switching data of the transmission for the drive torque and vehicle speed prepared in advance, and drives the switching drive means. Control.

[Example] Hereinafter, an example in which the present invention is embodied in a forklift will be described with reference to the drawings.

FIG. 1 shows the mechanism and electrical configuration of a forklift drive system, in which the output of an engine 11 is transmitted via a torque converter 12 to an automatic transmission 13 as a transmission, and via a differential gear 14, the drive wheels 15 are shifted to a predetermined position. Rotationally driven with a gear ratio of . The input shaft 16 of the transmission 13 is drivingly connected to an intermediate shaft 17 via gears Ga and Gb.

The intermediate shaft 17 is provided with a first speed (low speed) clutch CLI and a third speed (high speed) clutch CL3 which are wet type multi-disc clutches. When the first gear clutch CLI is connected with hydraulic oil, the intermediate shaft 17 is connected to the gear Gl.
a, is drivingly connected to the aft shaft 18 via Glb. Further, when the third speed clutch CL3 is connected, the intermediate shaft 17 is drivingly connected to the aft shaft 18 via gears G3a and G3b.

On the other hand, the output shaft 18 is provided with a second speed (medium speed) clutch CL2 which is also a wet type multi-plate clutch. Then, when the second speed clutch CL2 is connected, the intermediate shaft 17 and the output shaft 18
That's gear G2a.

Drive-coupled via G2b.

Each pair of gears Gla, Glb to G3a and G3b corresponding to each of the clutches CLI to CL3 constituting the switching drive means has different gear ratios in advance. Therefore, when the 1st gear clutch CLI is connected, the gear ratio suitable for low speed driving is connected, and when the 2nd gear clutch CL2 is connected, the 3rd gear clutch CL3 is connected to the gear ratio suitable for medium speed driving. Then, the transmission 13 is switched to a gear ratio suitable for high-speed driving.

Next, to explain the hydraulic circuit that constitutes the same (switching drive means) that operates each clutch CLI to CL3, the hydraulic oil sent from the hydraulic pump P is supplied to a 2-chamber, 4-port, 3-speed electromagnetic solenoid valve (hereinafter referred to as , 3-speed valve) SV3.Then, 3-speed valve S
When V3 is switched to the b position, hydraulic oil is supplied to the triple clutch CL3 and the clutch CL3 is connected. On the other hand, when the 3-speed valve SV3 is switched to the a position, hydraulic oil is supplied to the 2-chamber, 4-port 1-speed electromagnetic solenoid valve (hereinafter referred to as the 1-speed valve) SVI. Then, when the 1st speed valve SVI is in position a, 3
Hydraulic oil from pump P is supplied to second speed clutch CL2 via speed valve SV3, and second speed clutch CL2 is connected. Conversely, the first speed valve SVI is switched to the b position and the clutch CLI is connected.

Next, each of the 1st and 3rd speed valves SVI configured as above,
The electrical configuration for appropriately controlling SV3 will be explained.

The gear ratio control controller 21 as a speed ratio calculation means, an output torque calculation means, a drive torque calculation means, and a transmission ratio calculation control means is composed of a microcomputer or the like, and is installed in the engine 11 to detect the rotation speed Nl of the engine 11. A detection signal is input from the engine rotation speed sensor 22. The controller 21 is the gear G of the input shut 16
a, that is, the detection signal of the turbine rotation speed sensor 23 that detects the turbine rotation speed No of the torque converter 12 and the rotation speed of the gear Glb of the output shaft 18,
That is, the detection signal of the vehicle speed sensor 24 that detects the vehicle speed V is input. Then, the controller 21 outputs the engine speed NI
The speed ratio Rv of the torque converter 12 is calculated based on the turbine rotational speed NO, and various torques TIN, TO
, T are calculated.

Further, the speed ratio control controller 21 controls the torque ratio R of the torque converter 12 to the speed ratio Rv as shown in FIG.
It is equipped with a data map of T and capacity Ca, and
As shown in FIG. 3, a data speed change map of the speed change ratio determined by the vehicle speed (2) and the driving torque T is provided. The data map of the torque ratio RT and capacity CA of the torque converter 12 with respect to the speed ratio Rv is obtained in advance in a performance test of the torque converter 12. The shift map is determined in advance through tests and determines each shift range based on vehicle speed V and drive torque T, with boundary lines L12 and L23 being upshift boundaries, boundary lines L21 . L32 is the downshift boundary. Boundary line L1 for upshifting
2. L23 is a line connecting the intersections A and B of the driving performance curves shown in FIG. 8, which were obtained by keeping the accelerator pedal constant, obtained for each accelerator opening. This also enables smooth gear ratio changes when upshifting. Further, the boundary lines L21°L32 for downshifting are modified based on the boundary lines L12 and L23 to suit downshifting, and are determined experimentally.

The controller 21 controls the first speed and third speed valves SVI, 5.
V3 (7) Excite control of SLI and SL3, that is, switching control of 1st and 3rd speed valves SVI and SV3, to change and control the gear ratio of the transmission 13 as appropriate. In this embodiment, when the solenoids SVI and SV3 are energized, the valves SVI and SV3 are switched to the b position, and when they are de-energized, the valves SVI and SV3 are switched to the b position, respectively.
V3 returns to position a. The controller 21 also includes first and second shift lever switches SWI provided in the driver's seat.
, an operation signal is input from SW2. When the first shift lever SWI is operated, the controller 21 always maintains the gear ratio of the transmission 13 at the first speed regardless of the vehicle speed and drive torque at that time. When the second shift lever switch SW2 is operated, the controller 21 maintains the gear ratio of the transmission 13 in a state where the gear ratio can be changed only between 1st speed and 2nd speed. in this case,
Boundary line L23 of the speed change map. L32 is gone,
The 2nd speed range is expanded to the 3rd speed range. Both switches SWI
, when SW2 is not operated, the controller 21 is in a normal mode and controls the transmission gear ratio by switching between 1st and 3rd gears according to the shift map shown in FIG.

Next, the operation of the forklift constructed as described above will be explained according to the operation process of the speed ratio controller 21 shown in FIGS. 4 and 5.

First, the drive torque calculation routine will be explained. now,
In the normal mode in which the switches SWI and SW2 are not operated, the controller 21 first detects the engine speed sensor 22 and the turbine speed sensor 2 in step 101.
Based on the detection signal from 3, the engine speed NI at that time
and turbine rotational speed NO, and in step 102, the speed ratio RV (-N
Find O/NI). Subsequently, in step 103, the capacity Ca and torque ratio RT of the torque converter 12 for the speed ratio RV are determined from the data map shown in FIG.

Next, in step 104, the input torque TI of the torque converter 12 is calculated from the capacity Ca and the engine speed Nl.
After calculating N(-Ca-NI2), the process moves to step 105 and the output torque T of the torque converter 12 is calculated from the input torque TIN and the torque ratio RT.

Calculate (-RT-TIN). Then step 106
Then, the driving torque T (=r-TO) is calculated from the gear ratio r of the transmission 13 and the output torque TO at that time. In addition, the controller 21 has valves SVI,
Since SV3 is being controlled and the gear ratio r at that time is known, the calculation is performed using that gear ratio r. When the calculation is completed, the process moves to step 107, waits for 32 milliseconds, and then moves to step 101, where a new drive torque T is calculated.

That is, the controller 21 generates the driving torque T every 32 milliseconds.
is performing the calculation.

Next, the speed change control routine of the controller 21 will be explained.

The controller 21 detects the vehicle speed sensor 24 in step 201.
Based on the detection signal, the vehicle speed V at that time is calculated, and the drive torque T obtained by the drive torque calculation routine is read out. Next, in step 202, the current speed change range is determined from the data map shown in FIG. 3 using the current vehicle speed V and drive torque T. Next, step 203
It is determined whether the determined shift region has moved to a region different from the previous shift region. If the range has changed, the controller 21, in step 204, excites and controls the first and third speed solenoids SLI and SL3 so that the gear ratio corresponds to the shifted range. On the other hand, if there is no change, the process returns to step 201 and a new shift control routine is executed.

As described above, in this embodiment, since the change in the gear ratio is determined based on the drive torque T, the gear ratio is always changed at the intersection points A and B of the driving performance curve shown in FIG. As a result, smooth gear shifting becomes possible, and even if the output torque characteristics change due to the engine 11 being cold or due to aging, the engine 11 rotational speed does not rise to the rotational speed corresponding to the gearshift point. There is no problem of not being able to do it.

Therefore, in order to avoid this problem, point C in FIG. 9 is set to C1, which has a low rotational speed, as in the conventional method, so that the intersection point A on the driving performance curve in FIG.

B becomes points AI and Bl, respectively, and if the driving force after shifting decreases and the gear ratio is shifted up while driving, the vehicle speed decreases due to the decrease in driving force, resulting in a downshift. This solves the problem of repeatedly being knocked down and not being able to pitch smoothly.

Note that this invention is not limited to the above embodiments,
For example, although the turbine rotation speed sensor 22 is used to detect the turbine rotation speed NO, the present invention may be modified such that the turbine rotation speed sensor 22 is substituted with the vehicle speed sensor 24 and the turbine rotation speed NO is determined from the vehicle speed V and the gear ratio r at that time. It may be implemented with appropriate changes without departing from the spirit.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to reliably shift gears against performance changes such as changes in engine temperature and aging, and moreover, it is possible to perform smooth gear shifts, and torque It has excellent effects as an automatic transmission control device for vehicles equipped with a converter.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining the drive system and electrical configuration of a forklift embodying the present invention, Fig. 2 is a diagram for explaining the relationship between the capacity and torque ratio with respect to the speed ratio of the torque converter, and Fig. 3 is a diagram for explaining the relationship between the capacity and torque ratio with respect to the speed ratio of the torque converter. FIG. 4 is a flowchart illustrating the drive torque calculation process of the speed ratio controller; FIG. 5 is a flowchart illustrating the controller's speed change control process; FIG. 7 is a diagram for explaining the drive system and electrical configuration of a conventional forklift, FIG. 7 is a diagram for explaining the conventional accelerator opening and gear change status with respect to vehicle speed, FIG. 8 is a driving performance curve diagram, and FIG. It is an output torque curve diagram of an engine. In the figure, 11 is the engine, 12 is the torque converter, and 13 is the engine.
21 is a transmission as a transmission; 21 is a speed ratio control controller as a speed ratio calculation means, an output torque calculation means, a drive torque calculation means, and a speed ratio calculation control means;
22 is an engine rotation speed sensor as an engine rotation speed detection means, 23 is a turbine rotation speed sensor as a turbine rotation speed detection means, 24 is a vehicle speed sensor as a vehicle speed detection means, and CLI to CL3 are 1 to 3 as switching drive means. The speed clutch SVI is a first speed electromagnetic solenoid valve as a switching drive means, and SV3 is a third speed electromagnetic solenoid valve as a switching drive means. Patent applicant Toyota Industries Corporation representative
Patent Attorney On 1) Hironobu (and 1 other person) Figure 7 Dongliao Figure 8 East 19I! 1 engine specification number

Claims (1)

[Scope of Claims] An automatic transmission control device for a vehicle equipped with a torque converter, in which the transmission ratio of a transmission drive-coupled with an engine via a torque converter is controlled based on switching drive of a switching drive means, which controls the rotation of the engine. a turbine rotation speed detection means for detecting the turbine rotation speed of the torque converter; a vehicle speed detection means for detecting the vehicle speed of the vehicle; and an engine rotation speed detected by the engine rotation speed detection means. speed ratio calculation means for calculating the speed ratio of the torque converter based on the turbine rotation speed detected by the turbine rotation speed detection means; output torque calculation means for calculating the output torque of the torque converter based on the index, the capacity, the torque ratio, and the engine speed; and the drive torque calculation means for calculating the drive torque using the output torque and the gear ratio of the transmission at that time. and a gear ratio calculation control means for determining the current gear ratio from gear ratio switching data of the transmission for the drive torque and vehicle speed prepared in advance using the drive torque and the vehicle speed at that time, and controlling the drive of the switching drive means. Automatic transmission control device for vehicles equipped with torque converters.