JPH02286960A - Controller for automatic transmission - Google Patents

Abstract

PURPOSE:To restrain worsening of fuel consumption by providing a speed change pattern altering means for altering speed change patterns in such a way that the larger a load is, the more a speed change line is shifted to a high speed side according to the magnitude of a travelling load judged by a load judging means. CONSTITUTION:A controller 40 reads out a vehicle speed V, a throttle opening T and an engine speed N through respective sensors 41-43 and calcutes an acceleration A as a change rate of the vehicle speed V per time and reads out, from a map standard acceleration A0 corresponding to an operating state at this time. The standard acceleration A0 is compared with an actual acceleration, and it is judged that travelling load larger than the predetermined value is applied to the vehicle when the acceleration A is smaller than a predetermined proportion alpha (e.g. 85%) of A0. In this case, a power pattern wherein each speed change line is set at a high speed side is selected as a speed change pattern, and when it is judged that no large travelling load like the above- mentioned one is applied, a normal pattern wherein each speed change line is set at relatively low speed side is selected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic transmission for a vehicle, and particularly to a control device for an automatic transmission that changes a shift pattern according to a load.

(Prior art) In automatic transmissions, a preset shift pattern is compared with the actual driving condition indicated by vehicle speed, engine load, etc., and when the driving condition exceeds a shift line that constitutes the shift pattern, However, in recent years, the above-mentioned shift patterns have been changed to, for example, a normal pattern (economy pattern) in which each shift line is set to a low vehicle speed side in order to improve fuel efficiency. In order to improve output performance, multiple patterns are set, such as a power pattern in which each shift line is set to the high vehicle speed side, and one of these patterns can be selected manually by the driver. ing.

Also, for example, according to Japanese Patent Publication No. 51-22698,
A system is shown in which the shift line forming the shift pattern is automatically changed according to the driving condition. This detects the rate of change in the throttle opening of the engine, and for example, when the driver depresses the accelerator pedal to accelerate, the shift line shifts to the high speed side in response to the accompanying change in the throttle opening. By doing so, it is possible to obtain acceleration that meets the requirements.

<Problems to be Solved by the Invention> By the way, in the case where the shift pattern is changed by manual operation as described above, since the selection of the shift pattern is not appropriate, the normal pattern may be changed during high load driving such as when pitching. Because it is selected, the throttle opening is unnecessarily large, which worsens fuel efficiency, and because the power pattern is selected when driving at low load, the output becomes higher than necessary, which also worsens fuel efficiency. cases may arise.

In addition, in the case of a device that changes the gear shift line according to changes in throttle opening as shown in the above publication, careless accelerator operation may cause the gear shift line to change against the driver's will or unnecessarily. In this case as well, fuel efficiency will be unnecessarily worsened.

Therefore, when changing the gear shift line according to the driving condition as described above, the present invention makes this change appropriately based on the running load of the vehicle, thereby ensuring output performance that meets the demand. The challenge is to suppress deterioration of fuel efficiency as much as possible.

(Means for Solving the Problems) In order to solve the above problems, the present invention is characterized by having the following configuration.

In other words, the automatic transmission control device according to the present invention controls the throttle opening of the engine in an automatic transmission that compares a preset shift pattern with the operating state and controls the gear to the optimum gear. a throttle opening detection means for detecting the acceleration of the vehicle; an acceleration corresponding to the throttle opening detected by the throttle opening detection means; and an actual acceleration detected by the acceleration detection means. and a load determining means for determining the magnitude of the running load by comparing the values, and a shift pattern such that the shift line shifts to a higher vehicle speed as the load increases, according to the magnitude of the running load determined by the determining means. The present invention is characterized in that it is provided with a speed change pattern changing means for changing the speed change pattern.

(Function) According to the configuration described in ``-'', if the acceleration corresponding to the throttle opening of the engine is set in advance as the reference acceleration, for example, the acceleration obtained at each throttle opening when driving on flat ground, the load judgment can be performed. The running load of the vehicle is determined by comparing the actual acceleration with the reference acceleration corresponding to the throttle opening at that time. For example, when it is determined that the running load is large, such as when climbing a hill, the shift pattern changing means automatically changes the shift pattern to a pattern in which each shift line is set to a high vehicle speed side, thereby changing the gear position. The gear will be downshifted or held at a lower gear. As a result, an output corresponding to the driving load can be obtained as necessary while avoiding deterioration of fuel efficiency due to unnecessary changes in the shift pattern.

(Example) Examples of the present invention will be described below.

First, the configuration and control system of an automatic transmission according to an embodiment of the present invention will be explained with reference to FIG.
A power train 10 that changes the speed of the engine output and transmits it to the wheels; a hydraulic control circuit 30 that controls the supply and discharge of hydraulic pressure to the hydraulic actuators of the plurality of frictional engagement elements 15 to 20 in the power train 10; and the hydraulic control circuit 3
The controller 40 operates a plurality of solenoid valves 31 to 34 according to operating conditions.

The power train IO includes a torque converter 11 to which engine output is input, and first to third planetary gear mechanisms 12 to 14 driven by the output of the torque converter 11.
and a front clutch 1 which switches the power transmission path by these planetary gear mechanisms 12 to 14 to obtain a plurality of gears.
5, a rear clutch 16, a second brake 17, a low reverse brake 18, an overdrive clutch 19, an overdrive brake 20, and other frictional engagement elements, and a one-way clutch 21. By combining the engagement and disengagement of each of the frictional engagement elements 15 to 20 and the one-way clutch 21, 1st to 4th speeds and reverse speed are obtained as shown in the following equation.

(Hereinafter, blank space) The hydraulic pressure 11J control circuit 30 also includes first to third solenoid valves 31 to 33 for shifting and a fourth solenoid valve for operating a lock-up clutch 22 provided in the torque converter 11. 34, and the oil passage in the hydraulic control circuit 30 is switched by a combination of ON and OFF of the speed change solenoid valves 31 to 33, and hydraulic oil is selected for the actuator of each of the frictional engagement elements 15 to 20. is supplied, and the gear stage is changed according to the above formula. Further, by turning on and off the fourth solenoid valve, supply and discharge of hydraulic pressure to and from the lock-up clutch 22 are controlled, so that the clutch 22 is engaged or disengaged.

Further, the controller 40 receives a signal from a vehicle speed sensor 41 that detects the vehicle speed of the vehicle, and a throttle opening sensor 42 that detects the throttle opening as the engine load.
These signals are compared with preset shift patterns and lock-up patterns to select the most suitable gear for the driving conditions, and to adjust the lock-up according to the driving conditions. The first to fourth solenoid valves 31 to 34 are connected so that the clutch 22 is engaged and released.
Outputs a control signal to.

In addition to signals from the vehicle speed sensor 41 and throttle opening sensor 42 described above, a signal from an engine rotation sensor 43 that detects the engine rotation speed is input to the controller 40. A reference acceleration corresponding to the throttle opening degree is compared with an actual acceleration calculated based on the vehicle speed, and a shift pattern is selected according to the comparison result.

Next, the operation of selecting a shift pattern by the controller 40 will be explained according to the flowchart of FIG. 2.

First, in step SI, the controller 40 reads the vehicle speed {circle around (2), throttle opening}'', and engine speed N based on the signals from the sensors 41 to 43 shown in FIG. Acceleration A is calculated as the rate of change, and in step S3, a reference acceleration AO corresponding to the current driving condition is read from the map shown in FIG.

This map uses the engine speed N and throttle opening T as parameters, and for each of these parameters, the acceleration obtained during normal running on flat ground is defined as the reference acceleration A in each driving state. By applying the throttle opening T and engine speed N detected by the sensors 42 and 43 to this map,
Reference acceleration A corresponding to the operating state at that time. is required.

Next, the controller 40 compares the reference acceleration Ao obtained as described above in step S4 and the actual acceleration A calculated in step S2, and determines that the actual acceleration A is the reference acceleration A. (A<AOxα), it is determined that a large running load equal to or greater than a predetermined value is acting on the vehicle. If it is determined that such a large running load is being applied, a power pattern in which each shift line is set to the high vehicle speed side is selected as the shift pattern in step S5, and a power pattern in which the above-mentioned large running load is applied is selected as the shift pattern. If it is determined that this is not in effect, a normal pattern in which each shift line is set to a relatively low vehicle speed side is selected in step S6.

As a result, during normal driving where the running load is not particularly large, the automatic transmission will shift according to the normal pattern, which will increase the frequency of use of high gears, resulting in good fuel efficiency. If the driving load is large, such as when driving under such high load conditions, the shift pattern will be automatically switched to the power pattern, and the gear will be downshifted or held at a low gear. The output will be obtained.

(Effects of the Invention) As described above, according to the present invention, in an automatic transmission that changes the shift pattern according to the driving condition, the reference acceleration and the actual acceleration according to the throttle opening of the engine, etc. By comparing the values, the running load of the vehicle is determined, and the shift pattern is changed according to the result of the determination, so there is no need to unnecessarily change the shift pattern to a power pattern and deteriorate fuel efficiency. During high-load running, the shift pattern is automatically and appropriately switched to the power pattern, resulting in good running performance.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a diagram showing the structure and control system of an automatic transmission according to the embodiment, and FIG.
The figure is a flowchart showing the control for switching the shift pattern, and FIG. 3 is a map of the reference acceleration used in this control. 40...Load determination means, shift pattern changing means (controller), 41...Acceleration detection means (vehicle speed sensor)
, 42... Throttle opening detection means (throttle opening sensor). Figure Figure

Claims (1)

[Claims] (1) A control device for an automatic transmission that controls a gear to an optimal gear by comparing a preset shift pattern and operating conditions, and includes a throttle opening detection means for detecting a throttle opening of an engine. , the acceleration detection means detects the acceleration of the vehicle, and the acceleration corresponding to the throttle opening detected by the throttle opening detection means is compared with the actual acceleration detected by the acceleration detection means to determine the running load. a load determining means for determining the magnitude of the traveling load; and a shift pattern change for changing the shift pattern so that the shift line shifts to a higher vehicle speed as the load increases, depending on the magnitude of the running load determined by the determining means. 1. A control device for an automatic transmission, comprising: means.