JPS6148652A - Speed change control method of vehicular automatic transmission - Google Patents

Abstract

PURPOSE:To improve various characteristics such for example as specific fuel consumption, power performance, and shock produced in speed change, and thereby elimate uncomfortableness of a driver by achieving increased speed change stages in higher engine load while reduced speed change stage in lower engine load. CONSTITUTION:With higher engine load, many seed change stages are achieved, while with lower engine load, reduced speed changes achieved. Hereby, an engine can smoothly be changed in its speed without subjecting overload thereto, so that durability of a frictional member can be improved together with the improvement of specific fuel consumption, power performance, and speed change shock, etc. In addition, since the number of times of speed changes is reduced, uncomfortableness of a driver can be eliminated.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a speed change control method for an automatic transmission for a vehicle, and in particular, a main transmission capable of automatically changing gears related to at least vehicle speed, and a main transmission connected in series with the main transmission. The present invention relates to an improvement in a speed change control method for a vehicle automatic transmission equipped with an auxiliary transmission that is disposed in a vehicle and can switch between a low speed side and a high speed side. (Prior Art) In an automatic transmission, as the number of gears achieved increases, the change in engine speed during gear shifting decreases.
The amount of energy to be absorbed by the friction material is reduced, the durability of the friction material can be improved, and torque fluctuations (shift shock) during gear changes can be greatly reduced. . Conventionally, in order to increase the number of gears achieved, and to reduce design changes to existing automatic transmissions and provide manufacturing advantages, existing automatic transmissions have been developed that are capable of automatically changing gears at least in relation to vehicle speed. An automatic transmission that can achieve a large number of gears by using an automatic transmission as the main transmission and arranging in series a sub-transmission that can switch between a low speed side and a high speed side. Are known. For example, an overdrive device (0
/D) is connected in series to the input side or output side of the main transmission as an auxiliary transmission, and the first
By performing speed change control as shown in the table,
It is possible to achieve multi-stage shifting of six forward stages. By increasing the number of gears achieved in this way,
As mentioned above, improved durability of friction material, speed change 1
It is possible to reduce the shift shock caused by the engine, and since no excessive load is placed on the engine, it is possible to obtain good results in terms of fuel efficiency and power performance. Table 1

[Problems to be Solved by the Invention] However, in the automatic transmission in which the auxiliary transmission is arranged in series with the main transmission as described above to achieve multi-speed shifting, the main transmission Since the shift as a sub-transmission and the shift as an auxiliary transmission are performed alternately or at the same time, there are problems in that the shift control method becomes complicated and the shift frequency increases, which may cause discomfort to the driver. there were. In particular, the gear position of the entire automatic transmission changes from 2nd gear to 3rd gear,
When a hair shift is performed from the fourth gear to the fifth gear, the gear position of the main transmission is upshifted, but the gear position of the auxiliary transmission is downshifted. When the gear position of the entire automatic transmission is downshifted from 5th gear to 4th gear and from 3rd gear to 2nd gear, the gear position of the main transmission is downshifted, but the gear position of the auxiliary transmission is downshifted. gear is upshifted. When the shifting directions of the main transmission and the differential gear are reversed as described above, there is a problem in that the shift feeling becomes worse unless the timing of the shifting operation is appropriately and strictly controlled. [Effects of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and provides improvements in the durability of friction materials, reduction in torque fluctuations during gear shifting, improvement in fuel consumption, improvement in ° and power performance, etc. For vehicles, while maintaining the benefits of having more gears, it eliminates the driver's discomfort caused by increased gear shifting frequency or shifts in the shift timing of the main and auxiliary transmissions. An object of the present invention is to provide a method for controlling the speed change of an automatic transmission.

[Measures to Solve the Problems] The present invention includes a main transmission that can automatically switch gears at least in relation to the vehicle speed, and a main transmission that is arranged in series with the main transmission and that has a low-speed side and a high-speed side. In a shift control method for a vehicle automatic transmission equipped with an auxiliary transmission that can switch between The above objective is achieved by adopting a configuration that achieves one gear shift with fewer gears when the gear is low.・ Embodiments of the present invention allow the auxiliary transmission to shift only when the main transmission is in the highest gear when the engine load is low. The present invention is designed to effectively prevent discomfort caused by increased frequency of shifting and shifts in shifting timing, without significantly reducing the advantages of multi-stage shifting. Further, in an embodiment of the present invention, when the engine load is high, the main transmission and the sub-transmission are shifted alternately or simultaneously,
By achieving twice the number of gear stages that the main transmission has, the advantages of multi-speed shifting can be fully utilized when the engine is under high load. Further, in an embodiment of the present invention, the engine load condition is detected by the opening degree of the throttle valve, so that the engine load condition can be detected quickly and accurately with a simple structure. [Function] In the present invention, when the engine load is high, the number of gears that can be achieved is large, so that the gears can be shifted smoothly without putting an excessive load on the engine.As a result, the durability of the friction material is improved and the fuel efficiency is increased. The advantages of multi-speed shifting, such as improvement in power performance, improvement in shift shock, etc., can be fully exploited. Furthermore, when the engine load is low, the gear setting is changed so that the number of gears to be achieved is reduced, so the frequency of gear changes is reduced accordingly, and the driver's discomfort can be alleviated. Furthermore, when the engine load is low, the friction material is in a state where there are no problems in terms of durability, and the driver is also likely to be in a state where they want stable driving rather than power, so the overall effect is good. properties can be obtained. [Examples] Examples of the present invention will be described in detail below based on the drawings. FIG. 2 shows an example of an automatic transmission with a torque converter, in which a first embodiment of the automatic transmission control method for a vehicle according to the present invention is adopted. This automatic transmission 10 includes a torque converter 14 that receives the output of an engine 12, a main transmission 16 that has two planetary gears achieved by a Simpson type gear train, and is capable of switching between three speeds. The sub-transmission 18 is disposed in series on the output side of the engine 16 and is capable of switching between a low speed side and a high speed side, and the output of the engine 12 is shifted to a maximum of 6 forward speeds and transmitted to the output shaft 20. It is now possible to do so. That is, the Q automatic transmission 10 is operated by a central processing unit 26 that receives signals from a throttle sensor 22 that detects the throttle opening that reflects the load condition of the engine 12, a vehicle speed sensor 24 that detects vehicle speed, etc. , electromagnetic solenoid valves $1, $2, $3 in the main transmission control hydraulic circuit 28 and electromagnetic solenoid valve $4 in the sub-transmission control hydraulic circuit 30 are driven and controlled according to a preset shift pattern, Shift control is also performed. The solenoid valves S1 and S2 control the first to third speeds of the main transmission 16, and the electromagnetic solenoid valve S3 controls a lock-up clutch (not shown). Further, the electromagnetic solenoid valve S4 switches the sub-transmission 18 between low speed and high speed. In addition, the reference numeral 32 in the figure is a shift position sensor, which detects the positions of N (neural), D (drive), R (reverse), etc. operated by the driver, and 34 is a pattern select switch. E (economy driving) and P (power driving) are selected, numeral 36 indicates a water temperature sensor for detecting the engine cooling water temperature, and numeral 38 indicates a brake switch for detecting the operation of the brake. Next, the operation of this first embodiment will be explained with reference to the flowchart shown in FIG. First, when the engine 12 is started, the process proceeds to step 110, where six forward gears are determined in accordance with the vehicle speed and throttle opening in the main routine. Next, if it is determined in step 120 that the shift is an upshift, the process proceeds to step 130, where it is determined whether the throttle opening θ is larger than a predetermined throttle opening θ0. If it is determined that the throttle opening degree θ is larger than the set opening degree θ0, it is determined that the throttle opening degree is high, and the process proceeds to step 160 to utilize all of the shift patterns obtained by the main transmission 16 and the sub-transmission 18. Shift control is performed up to six forward speeds, and corresponding solenoid drive is performed in step -190. On the other hand, if it is determined in step 130 that the throttle opening degree θ is smaller than the throttle setting opening degree θ0, the process proceeds to step 140, and in order to change the number of gears to 4, the main gear 1i16 is set to the highest speed, that is, 3rd gear. It is determined whether or not it has entered. If it is determined that the main transmission 16 is not in third gear, the process proceeds to step 170, where the auxiliary transmission 18 is fixed to the low speed side, and gear change control using only the main transmission 16 is executed. A corresponding solenoid drive takes place. If it is determined in step 140 that the main transmission 16 is in third gear, the process proceeds to step 150, where the auxiliary transmission 18 is allowed to shift, and the conditions are met according to a predetermined shift diagram. A signal is then issued to shift the sub-transmission to the high speed side, and in step 190 the corresponding solenoid is actuated. Note that if it is determined in step 120 that there is no upshift, the process proceeds to step 125 and the township shift is performed.
If it is determined that a downshift is to be performed, the process proceeds to step 180 and a town shift i~ is executed according to a predetermined downshift control routine. Step 12
If it is determined that the shift is neither upshift nor downshift at 0.125, the gear position determined in step 110 is executed as is. According to this first embodiment, when the engine load is high, the gears are shifted at the highest number of gears that can be achieved (six gears), so the advantages of multi-stage shifting are improved durability of the friction material, improved fuel efficiency, and improved power. This improves performance and reduces gear shift shock. On the other hand, when the engine load is low, a four-stage gear shift control is performed, which is two gears less than this, which prevents the phenomenon of frequent gear shifting. , and main transmission 16
And sub-shift! ! 18 are selectively shifted in opposite directions, allowing the driver to drive more comfortably. FIG. 4 shows a second embodiment of the present invention. 'In this second embodiment, first in step 200 it is determined whether the throttle opening θ is larger than the set opening θ0. If it is determined that the throttle opening degree θ is smaller than the set opening degree θ0, the process proceeds to step 220, and a shift pattern for low throttle opening degrees as shown in FIG. 5 is selected. If it is determined in step 200 that the throttle opening θ is larger than the set opening θ0, the process proceeds to step 210, where a high throttle opening shift pattern as shown in FIG. 6 is selected. . Step 210
Alternatively, after the shift pattern is selected in step 220, the process proceeds to step 230, where the main routine determines the gear position according to the selected shift pattern according to the vehicle speed and throttle opening, and in step 240, the corresponding solenoid valve is activated. is driven. The shift pattern for high throttle opening in FIG. 6 is a pattern that allows shifting in all six gears,
The shift pattern for low throttle opening in FIG. 5 reduces the number of gears by performing only the shifts corresponding to 1.3.5.6. This shift pattern for low throttle opening is, as a result, a shift pattern in which the shift of the auxiliary transmission 18 is permitted only when the main shift gear 16 is in 3rd speed, and similarly to the first embodiment, the shift pattern is Only 2nd and 4th gears, where the shock could be large, are selectively eliminated to improve driving sensation. Nao, in the above two embodiments, when the engine load is low, the number of gears is reduced by allowing the auxiliary transmission to shift only when the main transmission is in the highest gear. The method of reducing the number of gears according to the invention is not limited to this, for example, the main transmission 1
Alternatively, the sub-transmission 16 may be allowed to shift only when the main transmission 16 is in the lowest gear, or this may be combined with the above embodiments, so that the main transmission 16 is in the lowest gear or the highest gear. The configuration may be such that shifting of the sub-transmission is permitted only at certain times. Furthermore, when the engine load is low, the auxiliary transmission maintains the high or low gear shift at that point until the engine load becomes high again.
It is also possible to adopt a configuration in which gear changes are performed only by the main transmission. Further, in the above embodiment, the engine load state is detected by the opening degree of the throttle valve, but the method for detecting the engine load according to the present invention is not limited to this. It may be configured to detect from the air amount or intake pipe pressure. Furthermore, in the above embodiments, the sub-transmission was provided on the output side of the main transmission, but in the present invention, the sub-transmission is provided on the side of the main transmission. It is obvious that it is good. Further, the auxiliary transmission may be one in which a gear ratio is specifically set, or may be a conventional overdrive device (low speed gear ratio is 1). Effects of the Invention As explained above, according to the present invention, when the engine is in a low load state, the number of gears achieved is small, the frequency of gear changes is reduced, and comfortable driving is possible. On the other hand, when the engine is under high load, it is possible to achieve more multi-speed shifting, which reduces friction, improves material durability, improves fuel efficiency, improves power performance, and reduces shift shock by 1q. Excellent effects can be obtained.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the main structure of the present invention, and FIG.
FIG. 3 is a block diagram illustrating an example of an automatic transmission with a torque converter, in which the first embodiment of the shift control method for an automatic transmission for a vehicle according to the present invention is adopted. FIG. 4 is a flowchart showing the speed change control routine according to the second embodiment of the present invention, and FIG. 5 is a flowchart corresponding to FIG.
The figure is a diagram of a shift pattern for a low throttle opening used in the second embodiment, and FIG. 6 is a diagram of a shift pattern for a high throttle opening. 10... automatic transmission, 12... engine,
14... Torque converter, 16... Main transmission, 18... Sub-transmission, 20... Output shaft, 26... Seihen i! Hydraulic circuit for machine control, 28... Hydraulic circuit for sub-transmission control. - Agent Takaya Ronmatsu 111 Kei Taimaki No Mll Hiroshi Figure 1 Figure 3 Figure 4

Claims (4)

[Claims] (1) A main transmission capable of automatically switching gears at least in relation to vehicle speed, and arranged in series with the main transmission,
In a shift control method for a vehicle automatic transmission equipped with a sub-transmission capable of switching between a low speed side and a high speed side, a large number of gears is achieved when the engine load is high, and a small number of gears is achieved when the engine load is low. A shift control method for an automatic transmission for a vehicle, characterized in that: (2) The automatic transmission for a vehicle according to claim 1, characterized in that when the engine load is low, the auxiliary transmission is allowed to shift only when the main transmission is in the highest gear. transmission control method. (3) When the engine load is high, the main transmission and the auxiliary transmission are shifted alternately or simultaneously to achieve a number of gears that is twice the number of gears that the main transmission has. A method for controlling a speed change of an automatic transmission for a vehicle according to scope 1. (4) The state of the engine load is detected based on the opening degree of the throttle valve.
3. A method for controlling a speed change of an automatic transmission for a vehicle according to any one of items 1 to 3.