JPS6288624A - Method for controlling speed change for automatic transmission - Google Patents

Abstract

PURPOSE:To make an engine-torque changing control proper one suited to a traveling condition by carrying out the start of the change of engine torque by monitoring various sensors while making a backup control by means of a timer when said sensors are out of order. CONSTITUTION:Normally, the accomplishment of an engine-torque change starting condition is detected by the detecting means of a sensor system other than a timer, to carry out the change of engine torque. However, when said detecting means fail due to the failure of the sensor system, and the like, the change of engine torque is carried out by means of a timer as a backup. As a result, a proper torque changing control suited to a traveling condition can always be carried out, preventing a friction engaging device from being overloaded. Also, the sensor system for inputting signals into computers 40, 50, consists of various sensors as follows: an engine speed sensor 108, a throttle sensor 102, a car speed sensor 110, a pattern select sensor 120, an O2 sensor 106, a water temp. sensor 104, an intake temp. sensor 100, an oil temp. sensor, etc.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a speed change control method for automatic transmission, and in particular, to change engine torque by detecting the establishment of engine torque change start conditions by means other than a timer during a speed change, so as to maintain good speed change characteristics. This paper is aimed at improving the speed change control method for automatic transmissions.

[Conventional technology]

It is equipped with a gear shifting mechanism and a plurality of frictional engagement devices, and selectively switches the engagement of the frictional engagement devices by operating a hydraulic control device, and selects one of the plurality of gears. Automatic transmissions for vehicles configured to achieve this are already widely known. By the way, in the above-mentioned automatic transmission for vehicles, the engine torque is changed during gear shifting to obtain good shifting characteristics, and the durability of the frictional engagement device is ensured and improved. Various integrated control methods have been proposed (for example, Japanese Patent Laid-Open No. 55-69738). In other words, this integrated control controls the torque transmission m from the engine during gear shifting.
By changing the amount of energy absorbed by each member of the automatic transmission or by the friction and retention device that brakes them, the gear shift can be completed in a short time and with a small shift shock, giving the driver a good shift feeling. The aim is to improve the durability of each fftff engagement device. In this way, the gear shift i that controls the engine torque by being in J3 during gear shifting.
The i control method integrates the automatic transmission and engine into one
It is attracting attention as a way to move forward with IJI, and is producing considerable results.

[Problems to be solved by the invention]

By the way, when changing engine torque during gear shifting,
If the timing of the start of the change or the start of return is not set properly, the engine torque will be changed at an unnecessary time, resulting in a large shift shock, or the shift time will become longer, resulting in the frictional engagement device becoming less durable. Problems such as deterioration of sex may occur. Therefore, in order to always ensure good transmission characteristics obtained by changing the engine torque, it is necessary to clearly decide when and how to change the engine torque. Conventionally, when changing the engine torque, it is known that the establishment of the starting condition is detected by the passage of a timer, and the other is detected by means other than the timer. As a means other than a timer, for example, one that detects based on a change in engine rotational speed is known. Although unknown, there is a method that detects by changing the oil pressure of a friction engagement device (Japanese Patent Application No. 59-241676), and a method that detects by changing the rotational speed of a rotating member in an automatic transmission (Japanese Patent Application No. 59-241676).
9-272609) may also be considered. When using a timer to start or restore engine torque change, a timer that uses the shift judgment or shift command as a standard is normally used, but if the timing is too early or There is a high possibility that this will lead to an increase. This is because the change in engine torque should start immediately after each member of the automatic transmission actually starts changing the rotation speed for gear shifting (Japanese Patent Application No. 59-234466
), this is because the time from the shift decision or shift command to the start of the rotational speed change of this member varies greatly depending on, for example, the stroke of the piston, the diameter of the orifice for oil pressure flow control, the oil temperature, etc. On the other hand, with devices that detect the establishment of engine torque change start conditions by means other than a timer, there are fewer problems due to such variations, but the sensor used to detect the establishment of change start conditions may malfunction. There is a problem that torque change control becomes impossible when this occurs. In this case, not only does the shift shock increase, but the frictional engagement device also prevents the engine torque from being changed (generally reduced).
Since the operating oil pressure is set according to the engine torque, unless the engine torque is changed, the engine will be placed in a more severe condition, which will cause problems in terms of durability.

[Purpose of the invention]

The present invention has been made in view of these problems, and it is possible to accurately determine the start of torque change under normal conditions by means other than a timer, and even in the unlikely event that the sensor system malfunctions. An object of the present invention is to provide a speed change control method for an automatic transmission that can execute the minimum necessary torque change using a backup timer.

[Means to solve the problem]

The present invention provides a shift υ control method for an automatic transmission in which the engine torque is changed by detecting the establishment of engine torque change start conditions by means other than a timer during the shift, and the shift characteristics are maintained favorably. As shown in FIG. 1, the procedure for determining whether the means for detecting the establishment of the engine torque change start condition has detected the establishment of the change start condition within a prescribed time from a predetermined time; The above object is achieved by including the step of forcibly changing the engine torque for a predetermined period of time when the predetermined period of time has elapsed when it is determined that no detection has been made.

[Effect]

In the present invention, under normal conditions, the establishment of the engine torque change start condition is detected by a detection means other than a timer that can more accurately grasp the gear shifting state of the automatic transmission. Changes can be made appropriately. On the other hand, when it becomes impossible to detect the establishment of the torque change start condition by means other than the timer due to a failure in the sensor system, etc., the timer is used as a backup to change the engine torque. Even in such a case, it is possible to prevent an excessive load from being placed on the frictional engagement device. It is a fact recognized from experience that the ratio of failures in computers that perform timer control is much lower than failures in various sensor systems. In a preferred embodiment, the predetermined time is a time when a shift is determined or a time when a shift command is issued. Thereby, the fail-safe function can be properly executed. Preferably, the predetermined time, the predetermined time, or the predetermined amount is determined by the speed change. ! ! The change is made depending on at least one of the following: type, engine load, select position η of the pattern select switch, engine cooling water temperature, vehicle speed, oil temperature of the automatic transmission, engine RII oil flow, and intake temperature. Thereby, even if the fail-safe function is executed and the torque change i, 11 is controlled by the timer, it is possible to perform torque change control appropriate to the driving conditions. Preferably, when the establishment of the change start condition cannot be detected by means other than the timer, the driver! The purpose of this is to ensure that the public is informed. This makes it possible to promptly notify the driver of a failure in the sensor system, allowing appropriate measures to be taken quickly.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 2 is an overall schematic diagram of an automatic transmission combined with an electronic fuel injection engine for an automobile that detects intake air suspension, to which the present invention is applied. Air taken in from the air cleaner 10 is sent to an air flow meter 12, a throttle valve 14, a surge tank 16, and an intake manifold 18 in order. This air is mixed with fuel injected from the injector 22 near the intake port 20, and is further sent to the combustion chamber 26A of the engine body 26 via the intake valve 24. Combustion chamber 2
Exhaust gas generated as a result of combustion of the air-fuel mixture in the exhaust valve 28, the exhaust port 30, and the exhaust manifold 3
2 and exhaust pipe 34 to the atmosphere. The air flow meter 12 is provided with an intake temperature sensor 100 for detecting intake temperature. The throttle valve 14 rotates fM=F in conjunction with an accelerator pedal (not shown) provided in the lotus seat. This throttle valve 14 is provided with a throttle sensor 102 for detecting its opening degree. Further, a water temperature sensor 104 for detecting the engine cooling water temperature is disposed in the cylinder block 26B of the engine main body 26, and a water temperature sensor 104 for detecting the oxygen concentration in the collecting part of the exhaust manifold 32 is disposed. 02 sensor 106 is provided. Further, the destroyer 38 having a shaft rotated by the crankshaft of the engine body 26 is provided with a crank angle sensor 108 for detecting a crank angle from the rotation of the shaft. Also, automatic transmission 1ffA/
The vehicle T is provided with a vehicle speed sensor 100 for detecting the vehicle speed from the rotational speed of its output shaft, and a shift position sensor 112 for detecting the shift position. Each of these sensors 100, 102.104.106.1
The outputs of 0B, 110, and 112 are input to an engine computer (hereinafter referred to as ECU) 40. ECLI4
0, the fuel injection amount is calculated using the input signals from each sensor as parameters, and the fuel injection amount is calculated using the input signal from each sensor as a parameter. ) The injector 22 is controlled so as to inject fuel for a predetermined period of time corresponding to one amount of fuel. Note that an idle rotation control valve (ISCV) is provided in the circuit that communicates the upstream of the throttle valve 14 and the surge tank 16.
) 42, and the idle rotation speed is controlled by a signal from the ECLJ 40. As shown in detail in FIG. 3, the ECU 40 includes a central processing unit (CPU) 40 consisting of a microprocessor.
A and 2. A memory 40B for storing II control programs, each scale, etc., and an analogue controller having a multiplexer function for converting analog signals from the intake air temperature sensor 1001, water filter sensor 104, etc. into digital signals and importing them. - Digital converter (A/D converter) 40C,
An input interface circuit 400 for directly receiving outputs from the throttle sensor 102, 02 sensor 106, crank angle sensor 108, vehicle speed sensor 110, shift position sensor 112, etc., and arithmetic processing of the CPU 40A]T! ! Depending on the result, the ignition coil 44
ignition signal to the injector 22, fuel injection signal to the injector 22, l
Idle rotation system to 5CV42! It consists of an output interface circuit 40E for outputting all signals and a signal to the ECT computer 50 for the automatic transmission A/T. On the other hand, the ECTTl monitor 50 includes a central processing unit (CPLI) 50Δ consisting of a microprocessor, and a
A memory 50B for storing ilJlil programs and various data, etc., a throttle sensor 102, a vehicle speed sensor 1101, a shift position sensor 112, a pattern select switch 120, a brake lamp switch 122
, the input interface circuit 500 for inputting the outputs from the cruise control switch 124 and the overdrive switch 126, and the solenoids 81, 32, 83 of the automatic transmission A/T according to the arithmetic processing results of the CPU 50A. It is composed of an output interface circuit 50E for outputting signals. The automatic transmission A/T includes a 2-3 shift valve 61 driven by the solenoid S, a 1-2 shift valve 62 and a 3-4 shift valve 63 driven by the solenoid S2, and a 3-4 shift valve 63 driven by the solenoid S3. It includes a driven lock-up clutch control valve 64, and shift valves 61 and 62 control a third-speed unit for obtaining a gear ratio configuration of 1st to 3rd speeds, and a shift valve 63 controls an overdrive gear ratio. An overdrive unit for obtaining the torque is controlled, and a lock-up clutch that mechanically directly connects the input and output sides of the torque converter is controlled by a lock-up clutch control pulp 64. Furthermore, this ECU 40 utilizes the fact that the reciprocal of the time interval of the signal output from the crank angle sensor 108 for each crank angle 30' is proportional to the engine rotational speed. Based on this calculation, the engine rotation speed is calculated. Further, the EC1J40 receives shift information (shift determination, shift command, lock-up clutch engagement permission, etc.) from the ECT computer 50, executes engine torque reduction control, and outputs this control information to the ECT computer 50. Based on this information, the ECT computer 50 issues a lock-up clutch release command and checks whether the above control is being performed reliably. In this embodiment, the ECU 40 and the ECT computer 50 are separate units, and the ECU 40 determines and executes the amount and timing of engine torque reduction. It does not limit the area. Next, the operation of this embodiment will be explained using FIG. 4. First, in step 200, the vehicle speed and engine load (
When a shift decision is made in the same way as in the conventional method depending on the throttle opening degree, etc., a shift command is issued in step 202. When this shift command is issued, the process proceeds to step 204, in which the engine rotational speed NO is calculated based on the output signal from the above-mentioned crank angle sensor 108, and the engine rotational speed NO is calculated based on the output signal from the above-mentioned crank angle sensor 108. It is determined whether or not the engine rotation speed FFNe1 that has been monitored is smaller than the previously monitored engine rotation speed aNe;-+. Here, when this determination is NO corresponds to an important point in this embodiment. That is, in step 206, the elapsed time t from the shift command to the present time is compared with the specified time Tgz. While the elapsed time t is smaller than the specified time Tgz, the flag F is set to 1 in step 302 in order to give priority to detection of the establishment of the torque down start condition by means other than the timer (detection of changes in engine speed) in step 204. It will be reset after that. When the elapsed time t becomes larger than the specified time Tg1, the process proceeds to step 210 and a forced engine torque change command (in this embodiment, the engine torque reduction start condition is not detected in step 204). A command to retard the ignition timing is issued. In this case, the engine torque change continues for a predetermined time T g 2 (step 214). Further, in step 212, the fact that the engine torque control has started after the specified time Tg1 is announced by, for example, a lamp display. Step 214
When it is determined that the predetermined time Tg2 has elapsed, a command to restore the engine torque is issued in step 216, and the flag F is reset (step 304), thereby ending the series of torque change control. Note that when the establishment of the condition for starting the torque change can be detected by means other than the timer in step 204, the torque is changed as usual based on the detection (step 220).
In step 222, the engine torque is restored by detecting that the engine torque restoration condition is met by means other than the timer. That is, in step 222, the return condition is satisfied by adding a constant 711N2, which is set in anticipation of slippage of the torque converter, to the engine rotational speed Ne, which is the output shaft rotational speed No. for each automatic transmission, plus the gear ratio ih. Judgment is made based on whether or not it is smaller than the object. Incidentally, steps 300 to 306 are steps related to setting a flag to substantially stop F-- until each condition in steps 204 and 206 or steps 214 and 222 is satisfied. FIG. 5 shows an example of setting the specified time Tgl (the time until it is determined that there is a malfunction in the sensor system). here,
The specified time Tg+ is set depending on the type of shift and the engine load (throttle opening). Generally I? [The piston stroke time of the engagement device (this is approximately equal to the time from when a gear shift command is received until each member of the automatic transmission actually starts changing the rotation speed for gear shifting) is It decreases from time to time. Further, this time differs depending on the type of each shift. Therefore, the specified time Tg1 is set taking this into consideration. In addition, FIG. 6 shows the predetermined m (engine ignition retard angle 1'CA).
) is shown below. Further, FIG. 7 shows an example of setting the predetermined time (engine torque change time) T g 2. When making these settings, the engine load (throttle opening)
The reason for making the speed change dependent on the lN type is the same as that described for the specified time Tgz. When making these settings, you should also check the vehicle speed, the selection position of the pattern select switch (distinguishing it from economical driving pattern or power driving pattern), automatic transmission oil temperature (or engine cooling water temperature, engine lubricating oil temperature, etc.). It is possible to further change the set value according to factors such as intake air temperature, etc., and although the ffi control becomes a little more complicated, it allows the 7 Aile Safe function to be activated earlier and more accurately. . In addition,
When considering these factors, when the selected position of the pattern select switch is in the power pattern, when the vehicle speed is high, or when the intake temperature is low, it is necessary to set the amount of It is preferable to change the torque for a longer time (predetermined time → large) and for a longer time (predetermined time → large). It is also advisable to reduce the torque early when the oil temperature of the automatic transmission is high or extremely low. A separate map may be provided for the settings, or the setting values shown in FIGS. 5 to 7 may be uniformly increased or decreased by a constant value. FIG. 8 qualitatively shows the effects of the present invention. The solid line in the figure is an example of execution of engine torque change control based on rotational speed detection. The turbine rotation speed is used as the rotation speed detection target. When the actual shift start of the automatic transmission is detected by detecting a change in the turbine rotational speed (point 0), a command is given to reduce the engine torque (point d), and the torque is reduced just before the end of the shift of the automatic transmission (point 1). Command to return. By the way, if the actual shift start timing of the automatic transmission cannot be detected due to a sensor system failure or other reason, the engine torque will not be reduced, and as shown by the dashed line in the figure, the shift time will increase and the energy absorption Φ of the frictional engagement device will be reduced. This increases the number of particles, which is disadvantageous in terms of durability. In the present invention, if the sensor system does not detect the establishment of the engine torque start condition even after a predetermined time Tg has elapsed after the shift command (0 points), a command to change the engine torque is issued at this point, and a predetermined time (1g2 ) By continuing to change the torque within a predetermined width, it is possible to achieve the characteristics shown by the broken line, and it is possible to prevent the problem of a large increase in the shift time. Note that the specified time Tg1 is only used to back up failures such as inability to detect by the sensor system, so it should be set to approximately the maximum value of the variation in the deflection period S of the return spring of the piston of the frictional engagement device shown in the same figure. do. In the present invention, there is no limitation on what means other than the timer is used to detect the establishment of the engine torque change start timing condition during normal conditions.

【Effect of the invention】

As explained above, according to the present invention, the shift state of the automatic transmission is actually monitored by various sensor systems under normal conditions, and the change in engine torque is started in accordance with the shift state, so that the timing is extremely appropriate. It is possible to control engine torque changes. On the other hand, even if a malfunction occurs in the sensor system and the gear shift state cannot be detected, backup II control using the timer is executed, so r! There is no excessive burden on the P, rM engagement device, and the r! The excellent effects of being able to prevent a decrease in the durability of the Jillj engagement device 1 and maintain good shifting characteristics are obtained.

[Brief explanation of drawings]

FIG. 1 is a flowchart without showing the gist of the present invention, and FIG. 2 is a flow chart showing an automatic transmission in combination with a vehicle electronic fuel injection engine to which an embodiment of the automatic transmission transmission control method according to the present invention is applied. 3 is a block diagram extracting and showing the input/output relationship of the engine and automatic transmission; FIG. 4 is a flowchart showing an embodiment of the present invention; FIGS. 5 to 7 The figure is a diagram showing an example of a map of the prescribed time Tg1, the prescribed amount of torque change, and the prescribed time T Is 2, respectively.
FIG. 2 is a shift characteristic diagram qualitatively showing the effects of the present invention. 102... Throttle sensor, 108... Crank angle sensor (engine speed sensor), 110... Vehicle speed sensor, 120... Pattern select switch, 1g1...
Specified time, Ta2...predetermined time, CA...predetermined m (retard angle M).

Claims (7)

[Claims] (1) In a shift control method for an automatic transmission, in which the engine torque is changed by detecting the establishment of engine torque change start conditions by means other than a timer during the shift, and good shift characteristics are maintained. A procedure for determining whether or not the means for detecting the establishment of the change start condition for the engine torque detects the establishment of the change start condition within a prescribed time from a predetermined time, and a step for determining whether the means for detecting the establishment of the change start condition for the engine torque has been detected within a prescribed time from a predetermined time; 1. A shift control method for an automatic transmission, comprising: forcibly changing engine torque by a predetermined amount for a predetermined period of time as time passes. (2) A shift control method for an automatic transmission according to claim 1, wherein the predetermined time is a shift determination time. (3) A shift control method for an automatic transmission according to claim 1, wherein the predetermined time is a shift command time. (4) The specified time depends on at least one of the following: type of gear change, engine load, select position of the pattern select switch, engine cooling water temperature, vehicle speed, automatic transmission oil temperature, engine lubricating oil temperature, and intake air temperature. 4. A shift control method for an automatic transmission according to any one of claims 1 to 3, characterized in that: (5) The predetermined time depends on at least one of the type of gear change, engine load, select position of the pattern select switch, engine cooling water temperature, vehicle speed, automatic transmission oil temperature, engine lubricating oil temperature, and intake air temperature. 5. A speed change control method for an automatic transmission according to any one of claims 1 to 4, characterized in that: (6) The predetermined amount depends on at least one of the type of gear change, engine load, select position of the pattern select switch, engine cooling water temperature, vehicle speed, automatic transmission oil temperature, engine lubricating oil temperature, and intake air temperature. 6. A shift control method for an automatic transmission according to any one of claims 1 to 5, characterized in that: (7) The automatic transmission according to any one of claims 1 to 6, which warns the driver when the establishment of the change start condition cannot be detected by means other than the timer. transmission control method.