JPS62242169A - Controlling method for automatic transmission - Google Patents

Abstract

PURPOSE:To aim at improvement in accelerating sensation and drivability, by installing a delay condition in changeover between an ordinary shift pattern and a power weighing shift pattern. CONSTITUTION:In the case excepting when an internal combustion engine is in lean control (A), gear shifting of an automatic transmission is carried out with an ordinary shift pattern (B), and gear shifting control in the case of using this ordinary shift pattern is continued till the internal combustion engine comes to the lean control (C) and after ward a delay condition is satisfied. When the engine is in the lean control (A), the gear shifting control of the automatic transmission is carried out (E) with a power weighing shift pattern, and the gear shifting control in the case of using this power weighing shift pattern is continued till the engine comes to the case other than the lean control (F) and afterward the delay condition is satisfied (D). With this constitution, frequent gear shifting attributable to frequent selection of these shift patterns is brought to nothing so that improvements in accelerating sensation and drivability are well promotable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of controlling an automatic transmission included in an internal combustion engine that performs lean control.

[Prior Art] Conventionally, as a technique for controlling an automatic transmission according to the state of a vehicle, a technique disclosed in Japanese Patent Laid-Open No. 57-184755 has been proposed.

That is, in the above technology, the gear is normally shifted to a gear determined from the normal shift pattern based on the throttle opening and the vehicle speed. Or, only when the cooling water temperature is in a predetermined state, control is performed to change the shift pattern from a normal shift pattern to a pattern suitable for the predetermined state.

[Problems to be Solved by the Invention] However, the above techniques do not take into account the air-fuel ratio state in which the combustion state and output characteristics of the internal combustion engine change significantly, particularly the lean air-fuel ratio state. As a result, when trying to accelerate the vehicle with the same vehicle speed and throttle valve opening as in normal conditions when the air-fuel ratio is lean, the output is lower than in normal cases, causing the driver to feel strange about the acceleration state. There was also the problem that the accelerator pedal was depressed too much due to lack of acceleration, which resulted in a decrease in fuel efficiency.

[Means for solving the problem] As shown in FIG.
The automatic transmission is shifted using a normal shift pattern (B). Then, the shift control using the normal shift pattern is continued until the internal combustion engine is put into lean control (C) and the delay condition is satisfied (D>).

On the other hand, when the internal combustion engine is under lean control (A), the automatic transmission is controlled using a shift pattern that emphasizes power (
E). Shift control using the power-oriented shift pattern causes the internal combustion engine to perform other than lean control ("),"
This continues until the delay condition is satisfied (D>).

The lean control is, for example, when the ratio of fuel and air supplied to the internal combustion engine is controlled to be leaner than the stoichiometric air-fuel ratio.

The above-mentioned normal shift pattern is, for example, a shift pattern that is normally used and is a pattern that can instruct an appropriate shift gear when control is being performed other than during lean control.

The power-oriented shift pattern is, for example, a pattern that instructs a lower speed gear than the shift gear provided by the normal shift pattern when the same shift conditions as those given to the normal shift pattern are given.

The delay condition is, for example, a combination of elapsed time or air-fuel ratio control conditions.

[Operation] By using the present invention, in cases other than lean control,
A normal shift pattern is used, while a shift pattern emphasizing power is used during lean control.

This power-oriented shift pattern is maintained until the internal combustion engine is no longer under lean control and the delay condition is satisfied. On the other hand, the normal shift pattern is maintained until the internal combustion engine enters lean control and the delay condition is satisfied.

Therefore, as shown in FIG. 2 or 3, during lean control, the normal shift pattern is switched to a shift pattern emphasizing power in the direction of arrow a. In FIGS. 2 and 3, the dotted line is a downshift line from 4th gear to 3rd gear, and the solid line is an upshift line from 3rd gear to 4th gear.

FIG. 2 shows a case where both shift lines are moved largely in the a direction, while FIG. 3 shows a case where both shift lines are moved a
This shows the case where the image is moved slightly in the direction.

Here, the differences between the cases of FIG. 2 and FIG. 3 described above will be explained. In the case of FIG. 2, since the shift line has moved significantly, it is possible to largely compensate for the decrease in output of the internal combustion engine during lean control.

On the other hand, in the case of Fig. 3, the shift line has moved small, so it is not possible to greatly compensate for the decrease in the output of the internal combustion engine, but even if the control changes from this state to something other than one-in control, the shift point This makes it possible to prevent hunting.

In other words, this shift point hunting refers to, for example, when the automatic converter is controlled with a shift pattern emphasizing power in Fig. 2, the throttle opening is increased from point b at 40 degrees/h in 4th gear. In this case, when the vehicle crosses the downshift line at the 0 point, it is downshifted to 3rd gear, and then accelerates and increases the vehicle speed in the direction of arrow d, and when it reaches the 0 point,
Shift point hunting is a phenomenon that occurs when the transition condition to a non-lean condition is satisfied and the shift pattern is switched from a power-oriented shift pattern to a normal shift pattern. That is, if switching between the power-oriented shift pattern and the normal shift pattern is repeated, a phenomenon occurs in which the shift is also repeated at the same time based on the above-described operation.

Therefore, in the present invention, a delay condition is provided for switching between a power-oriented shift pattern and a normal shift pattern, thereby preventing shift hunting, for example.

[Example] A first embodiment of the present invention will be described below.

In FIG. 4, 10 is an engine and 20 is an automatic transmission. The engine 10 is operated with fuel supplied from a fuel injection valve 12 provided in an intake passage 11 at a lean air-fuel ratio or a non-lean air-fuel ratio. automatic transmission 20
is a solenoid valve 21a.

Hydraulic pressure is controlled by energizing or de-energizing 21b, thereby enabling four-speed shifting.

The electromagnetic valves 21a, 21b and the fuel injection valve 12 are driven by signals from a control circuit 30, and the control circuit 30 receives signals from sensors located in various parts of the vehicle including the engine 10 and automatic transmission 20. signal is being input.

These sensors include a throttle opening sensor 14 that detects the opening of the throttle valve 13 disposed in the intake passage 11 of the engine 10, an idle switch 15 that detects the opening and closing of the throttle valve 13, and a sensor that detects the rotation speed of the engine 10. An engine rotation speed sensor 16 for detecting, an intake pressure sensor 17 for detecting intake pressure, and an air-fuel ratio sensor 18 for detecting air-fuel ratio.
, an ignition switch sensor 19 that monitors the ignition switch, and an automatic gear shift 1 that is proportional to the vehicle speed.
! The vehicle speed sensor 22 detects the rotation speed of the output shaft 20C.

The control circuit 30 is constituted by a well-known microcomputer, that is, CPU31, RAM32, ROM3
3, an input port 34, an output port 35, a common bus 36, etc. The input port 34 receives signals from the above-mentioned sensors through a pulse input section 36a,
36b and A/D converters 37a and 37b. The output port 35 is connected to electromagnetic valve drive units 38a, 38b and a fuel injection valve drive unit 39. The ROM 33 contains a downshift pattern shown in FIG. 2 for switching the automatic transmission 20,
and upshift patterns etc. are memorized, and
Flowcharts as shown in FIGS. 5 and 6 are stored.

In this embodiment, the air-fuel ratio correction coefficient FLEAN is calculated based on the flowchart in FIG.
Based on the value of AN and other requirements, switching is performed between an economy shift pattern and a power shift pattern (shift pattern emphasizing power).

In FIG. 5, the air-fuel ratio correction coefficient FLEAN of the engine 10 is
The calculation routine is shown. In this routine, it is first checked whether the lean condition is established, for example, if the cooling water temperature is TH.
W≧80℃, vehicle speed SPD change rate ΔSPD is 5 per 2 seconds
A determination is made based on whether all conditions such as the speed of travel at a speed of less than km/h and a throttle opening of less than 30' are satisfied (step 100). If it is determined that the lean control conditions are satisfied in this judgment, the idle switch (abbreviated as LL) is used.
15 is "off" and if it is not "off", that is, if it is idling, step 110), calculates the average value NAV of the engine rotation speed Ne for a predetermined time (step 12o), NAV is a predetermined average value B,
For example, it is determined whether or not it exceeds 600 ppm (step 13o). Based on this NAV>8 judgment, rYEs
If it is determined to be J, the air-fuel ratio correction coefficient FLEAN is set to 0.92, which is on the lean side (step 140), and this routine is temporarily terminated.

On the other hand, if the lean control condition is satisfied (step 100) and the idle switch 15 is "off", that is, not idling, the air-fuel ratio correction coefficient FLEAN is set based on the intake pressure PM and the engine speed Ne.
It is determined by interpolation from the LEAN map and set to FLEAN (step 150). Then, if lean control is currently in progress, this routine is temporarily terminated, and if lean control is not in progress (step 160), the vehicle 1sPD is 10 km/h.
(Step '170)
, and if SPD>10km/h, this routine is temporarily terminated, and if SPD≦10km/h, FLE is executed.
The AN is changed to 1, and this routine is temporarily ended (step 180). Further, if it is determined in step 100 whether the lean control condition is satisfied, if the condition is not satisfied,
Air-fuel ratio correction coefficient FLEAN without lean correction 1
0 (step 180).

Next, a control routine of the first embodiment for changing the shift pattern of the automatic transmission 20 based on FLEAN set above will be described.

In FIG. 6, first, after starting the engine 10, it is determined whether lean control has been performed up to this point (step 200). In other words, ignition switch 19
is "ON" (abbreviated as IGON in the flowchart) and the air-fuel ratio correction coefficient FLEAN is FLEAN<'
1, and if FLEAN is not less than 1 (step 200), an economy shift pattern is set (step 250).

This prevents the power shift 1 from being erroneously cut in the condition judgments in steps 220 to 240, which will be described later, during cold conditions when lean control is not performed.

Next, if lean control has been performed even once after starting, that is, if warm-up has been completed (step 200>
, is not under lean control (step 210), is not under negative pressure power (described in detail in the notes) (step 220), and the rate of change in vehicle speed is less than or equal to 5/i per 2 seconds (step 230>
, and if the opening degree of the throttle valve 13 is not 30" or more (step 240), an economy shift pattern is set (step 250). On the other hand, if the above conditions are not satisfied, that is, the lean control (step 210), negative pressure power (step 2
20>, if the rate of change in vehicle speed exceeds 5 gaps/h per 2 seconds (step 230), or if the throttle opening is 30" or more (step 240), the power shift pattern is set.The above negative pressure power is turned on when the pressure inside the intake pipe goes from 680mH9 or less to 700YanagiH3 or more, and 700#1IlIH
It is turned off when the value falls from 9 or more to 680IrIII4Hg or less, which is a state in which the amount of intake air is increased, that is, a state in which a large output from the engine 10 is required.

By using the first embodiment described above, it is possible to switch to a power shift pattern during lean control. Then, while the power shift pattern is switched to, for example, if the vehicle speed change rate ΔSPD, which is one of the lean conditions shown in step 100 of FIG. 5, exceeds 5 (/m/i) per 2 seconds. Even when the non-lean state is restored, the shift pattern does not change from the power shift pattern to the economy shift pattern, and steps 220 to 2 in FIG.
If all of the determinations in step 40 are in favor of switching to the economy shift, that is, if the delay condition is satisfied, the shift pattern is switched to the economy shift pattern.

Therefore, even if the engine 10 repeats control between the lean air-fuel ratio and the non-lean air-fuel ratio, in this embodiment, as long as the delay condition combining the conditions for shifting to the non-lean air-fuel ratio is not satisfied, the economy shift pattern It will no longer be possible to switch to As a result, the shift pattern is not changed frequently, and frequent shifts caused by the shift pattern change are eliminated.

If the delay condition is increased by W4, the economy shift pattern is returned to, so that deterioration in fuel efficiency, etc., which is a disadvantage of using the power shift pattern, can be prevented.

Next, the control routine of the second embodiment shown in FIG. 7 will be explained. In this embodiment, as in the first embodiment, in order to prevent the power shift from being set when only non-lean air-fuel ratio control is performed, such as during startup, lean control is It is determined whether lean control has been performed (step 300), and if lean control has not been performed up to this point, an economy shift pattern is set (step 330). If lean control has been performed up to this point, but it is not currently in lean control (step 310), if more than 5 seconds have passed since lean control stopped (step 32o) , an economy shift pattern is set (step 33o). On the other hand, if lean control is being performed after startup (step 300), and lean control is currently in progress (step 310), or if more than 5 seconds have not elapsed since lean control ceased, step 3
20) In either case, a power shift pattern is set (step 34o).

By using the second embodiment described above, the power shift pattern shifted from the economy shift pattern continues for at least 5 seconds or more. Therefore, frequent switching of shift patterns is eliminated. As a result, frequent gear changes are eliminated and drivability is improved.

Next, the control routine of the third embodiment shown in FIG. 8 will be explained. In this embodiment, similarly to the second embodiment, if lean control has not been performed from the time of startup to the present time (step 400), an economy shift pattern is set (step 430). If there has been lean control up to now (step 400), if lean control is not currently in progress (step 410), and if an upshift has been performed since the previous execution of this routine, (step 420) An economy shift pattern is set (step 430).

On the other hand, if lean control is currently being performed (step 410) or if no upshift is being performed (step 4
20), a power shift pattern is set (step 440).

Therefore, by using this embodiment, when the engine 10 is no longer under lean control, an economy shift pattern is set if it has been upshifted, and a power shift pattern is set if it has not been upshifted. Ru. As a result, a shift pattern in which a shift does not occur at the same time as the shift pattern is switched is set, so frequent shifts caused by switching the shift pattern can be prevented.

Next, the control routine of the fourth embodiment shown in FIG. 9 will be explained. In this embodiment, while lean control is not being performed after startup (step 500), an economy shift pattern is set (step 510), and on the other hand, from the time lean control is performed, the power shift pattern continues. (Step 520).

Therefore, if the lean control is executed even once after starting, the power shift pattern is set until the engine is stopped and restarted, thereby preventing frequent gear changes caused by changing the gear shift pattern.

[Effects of the Invention] According to the present invention, when the internal combustion engine is not controlled in a lean manner, a normal shift pattern is set, while when the internal combustion engine is under lean control, a shift pattern that emphasizes power is set. A shift pattern is set.

This power-oriented shift pattern is maintained until the delay condition is satisfied even if the internal combustion engine shifts to a state other than lean control. On the other hand, the normal shift pattern mentioned above is
Even if the internal combustion engine shifts to lean control, this is maintained until the delay condition is satisfied.

Therefore, even when the air-fuel ratio control of the internal combustion engine is frequently switched, the shift pattern is not switched frequently, and as a result, frequent shifts caused by frequent switching of the shift pattern are eliminated. As a result, the shift pattern emphasizing power is effectively used during lean control without being frequently switched to the normal shift pattern, making it possible to improve the sense of acceleration and drivability.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the basic configuration of the present invention, FIGS. 2 and 3 are graphs showing characteristics of the shift pattern of the present invention, FIG. 4 is a configuration diagram of an embodiment of the present invention, and FIG. A flowchart of the air-fuel ratio correction routine of this embodiment, FIG. 6 is a flowchart of the shift point change routine of the first embodiment, FIG. 7 is a flowchart of the shift point change routine of the second embodiment, and FIG. 8 is a flowchart of the shift point change routine of the third embodiment. Flowchart of Example Shift Point Changing Routine FIG. 9 is a flowchart of the shift point changing routine of the fourth embodiment. 10... Engine 13... Throttle valve 14... Throttle opening sensor 16... Engine rotation speed sensor 20... Automatic converter

Claims (1)

[Scope of Claims] When the internal combustion engine is not under lean control, the automatic transmission is controlled using a normal speed change pattern.On the other hand, when the internal combustion engine is under lean control, a speed change pattern that emphasizes power is used compared to the normal speed change pattern. A control method for an automatic transmission that performs speed change control of the automatic transmission using the above-mentioned automatic transmission, further comprising providing a delay condition for switching between the normal speed change pattern and the power-oriented speed change pattern. A method for controlling an automatic transmission characterized by: