JPS60139956A - Control for automatic speed change gear - Google Patents

Abstract

PURPOSE:To reduce the speed-change shock on shift-down by permitting the shift to a low-speed shift when it is detected that an operating brake is in operation and the number of engine revolution is below a prescribed number of revolution when the speed change ratio is within a high-speed ratio. CONSTITUTION:In an automatic speed change gear in which a manual speed change gear 3 provided with 4-stages for advance and one-stage for retreat and a sub speed change gear 4 equipped with hydraulically driven high-speed and low-speed clutches 27 and 28 are integrally installed into a common case 5, and the high-speed clutch 27 is connected by the electric conduction to a solenoid valve 33 through a control circuit, and the low-speed clutch 28 is connected by deenergizing a solenoid valve 34, input and output revolution-angle sensors 37 and 38, a brake switch, etc. are connected to the control circuit. When the control circuit detects that the speed change ratio is within a high-speed ratio and a brake is in operation, the solenoid valves 33 and 34 are controlled so that the shift-down to a low-speed ratio is performed when the number of engine revolution lowers below a prescribed number of revolution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling an automatic transmission in a vehicle equipped with an internal combustion engine.

Automatic transmissions are designed to automatically downshift when the driver starts decelerating while driving at a high ratio. However, when the vehicle is decelerating, the engine output torque fluctuates as the engine speed decreases, so depending on the start timing of the downshift operation, a large shift shock may occur during the downshift.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for controlling an automatic transmission that can reduce the shock caused by downshifting during deceleration operation.

The automatic transmission control method according to the present invention is characterized by shifting to a low speed ratio when it is detected that the operating brake is activated and the engine speed has fallen below a predetermined speed when the automatic transmission is in a high speed ratio.

Hereinafter, an example of collecting mud according to the present invention will be explained with reference to the drawings.

FIG. 1 shows a power transmission system of an automobile to which the control method according to the present invention is applied.

In this figure, the rotational power generated by an engine 1 is transmitted by a clutch 22, a manual transmission 3. Then, the wheels (
(not shown). the law of nature? The rim 22, manual transmission 3, and auxiliary transmission 4 are integrally formed by a case 5. The manual transmission 3 includes a clutch shift 6, a counter shaft 7, a drive shaft 8. Clutch gear9. Counter gear 1° to 14. Third speed gear 15. Second speed gear 16. It is a synchronous mesh type transmission with four forward speeds and one reverse speed, consisting of a first speed gear of 17 degrees, a synchronizer of 18 and 19 degrees, and a reverse gear of 2 degrees.

Sub-transmission 4 is sun gear 21.7' lane carrier 22
．． It is a planetary gear type two-stage automatic transmission using a planetary pinion 23 and a ring gear 24.

The sun gear 21 is rotatably provided on a drive shaft 8 which is the output of the manual transmission 3, and the planetary carrier 22 is fixed to the drive shaft 8 which forms a shaft into which the auxiliary transmission 40 is input. A plurality of planetary pinions 23 meshed with the sun gear 21 are planetary 7/Yaria 22.
They are rotatable and are equally spaced apart from each other. A ring gear 24 meshed with each of the planetary pinions 23 is connected to the drive shaft 8 via a one-sided clutch 25 and is fixed to an output shaft 26. The one-way clutch 25 becomes engaged when the drive shaft 8 attempts to rotate at a rotation speed exceeding the rotation speed of the ring gear 24, and in this state, the drive shaft 8 and the ring gear 24 are connected. Further, the sub-transmission 4 has a high-speed clutch 27 and a low-speed clutch 28 which are hydraulically operated multi-plate clutches. When the high-speed clutch 27 is engaged, the high-speed clutch 27 fixes the sun gear 21 to the case 5, and the rotational power of the drive shaft 8 is transferred to the planetary carrier 22. It is transmitted to an output shaft 26 via a planetary pinion 23 and a ring gear 24, so that the gear ratio is a high speed ratio. Further, when the low speed clutch 28 is engaged, the planetary carrier 22 and the ring gear 24 are connected via the low speed clutch 28 to form a direct three-way connection, so that the gear ratio becomes a low speed ratio.

As shown in FIG. 2, pressure oil is supplied to the high-speed clutch 27 from a hydraulic power source 30 via a hydraulic passage 31, and pressure oil is supplied to the low-speed clutch 28 via a hydraulic passage 32 branched from a hydraulic passage 31. Ru. A solenoid valve 33 is provided downstream from the branch point of the hydraulic passage 51 to the hydraulic passage 32, and a solenoid valve 34 is also provided in the hydraulic passage 32. When the solenoid 3jα of the solenoid valve 33 is de-energized, the valve body 33b moves to the left due to the urging force of the spring 33c and blocks the hydraulic passage 31, and when the solenoid 33a is energized, the valve body 3
3b moves to the right in the figure against the biasing force of the spring 33c, thereby communicating the hydraulic passage 3'1. j
When the solenoid 34α of the solenoid valve 34 is de-energized, the valve body 34b is moved to the left by the urging force of the spring 34c to communicate with the hydraulic passage 32', and when the solenoid 34a is energized, the valve body 34b is moved to the left by the urging force of the spring 34c. The hydraulic passage 32 is closed by moving to the right in the figure against the biasing force of the spring &'34c. Energization/de-energization of the solenoid valves 33.4-34 is controlled by a control circuit 35, which will be described later.

As shown in FIG. 3, the control circuit 35 includes solenoid valves 33 and 34.
In addition, there is also an engine rotation angle detection sensor 36 that is synchronized with the rotation of the force shaft of the engine 1 and generates an angular position signal with a period of rotation, and an engine rotation angle detection sensor 36 that is proportional to the rotation speed of the drive shaft 8. An input rotation angle detection sensor 37 that generates a periodic angular position signal, an output rotation angle detection sensor 38 that generates a periodic angle and position signal proportional to the rotation speed of the output shaft 26, and a throttle valve (not shown). Throttle opening sensor 39 that generates an output voltage according to the opening
, a solenoid valve 40 that forcibly closes the throttle valve described above in order to reduce the engine speed, and a brake switch that turns on and outputs a predetermined voltage when the foot brake (not shown) of the vehicle is depressed. 4.1 is connected. Engine rotation angle detection sensor 36, input rotation angle detection sensor 37, and output rotation angle detection sensor 38
This is a magnetic detection method consisting of a permanent magnet and a magnetic detection element.

The control circuit 35 includes waveform shaping circuits 51 to 53 which are provided corresponding to the rotation angle detection sensors 36 to 38 and which shape the angular position signals into waveform pulse signals, and the generation interval of the output pulses of the waveform shaping circuit 51. an M-counter 55 that measures the clock pulses counted by the engine and generates a digital signal representing the engine speed; and a waveform shaping circuit 52.
an NIN counter 56 that measures clock pulses counted at the generation interval of output pulses and generates a digital signal representing the rotation speed of the drive shaft 8; and a clock pulse counted at the generation interval of the output pulses of the waveform shaping circuit 53. N which measures the number of revolutions of the output shaft 26 and generates a digital signal representing the rotational speed of the output shaft 26. Accounter 57 and
A level correction circuit 59 that corrects the output level of the throttle valve opening sensor 39, an A/D converter 61 that converts the output voltage of the level correction circuit 59 into a digital signal, and a level correction circuit that corrects the output level of the brake switch 41. circuit 69, a data input circuit 70 to which the output voltage of the level correction circuit 69 is supplied, drive circuits 62 to 64 for each of the solenoid valves 33, 34, and 40, a CPU 65, various processing programs, and the sub-transmission 4. R where gear ratio etc. are memorized
Consists of OM66 and RAM67, counter 5
5 to 57, A/D converter 61, drive circuit 62 to 64, CPU 65, ROM 66, RAM 67
and data input circuit 70 are connected by a data bus line 68.

Further, the output pulse of the waveform shaping circuit 51 is supplied to the 0PU 65 as an interrupt signal.

In such a configuration, the engine rotational speed Ne and the rotational speed NIN of the drive shaft 8 are input from the counters 55 to 57.
And the data of the rotation speed N0UT of the output shaft 26 is
The A/D converter 61 receives data on the throttle valve opening, and the data input circuit 70 receives data on the foot brake operation.
Inactive data is provided to CPU 65 via pass line 68. The CPU 65 reads each of the above data according to the calculation program stored in advance in the ROM 66, and based on the data determines whether the downshift condition or shift-up condition of the sub-transmission 4 is satisfied. do. When the downshift condition is satisfied, a shift command signal is generated in the order of a high speed clutch off signal and a low speed clutch on signal, and when the upshift condition is satisfied, a low speed clutch off signal, a torque down on signal, and a high speed clutch are generated. A shift command signal is generated in the order of an on signal and a torque down/off signal.

The drive circuit 62 starts driving the solenoid valve 33 to open by energizing the solenoid 33g in response to the high-speed clutch-on signal. When the solenoid valve 33 is opened, pressure oil is supplied to the hydraulic source 3.
0 is supplied to the high-speed clutch 27 via a hydraulic passage 31 having a throttle 31cz, and the high-speed clutch 27 is engaged. In addition, the drive circuit 62 stops driving the solenoid valve 33 to open in response to the high-speed clutch off signal, so that the pressure oil flows through the throttle 3.
1b, and the high speed clutch 27 is released.

The drive circuit 63 de-energizes the solenoid 34α in response to the low-speed clutch-on signal, thereby stopping the closing drive of the solenoid valve 34 and opening the solenoid valve 34. Solenoid valve 3
When the valve 4 is opened, pressure oil is supplied from the hydraulic source 308- to the low-speed clutch 28 through a part of the hydraulic passage 31 and the hydraulic passage 32 having the throttle 32α, and the low-speed clutch 28 is engaged. Further, the drive circuit 63 starts closing the electromagnetic valve 34 in response to the low-speed clutch off signal, so that the pressure oil is discharged through the throttle 32b and the low-speed clutch 28 is released.

The drive circuit 64 operates the solenoid valve 4 in response to the torque down-on signal.
0 to close the throttle valve from the opening set by the driver to, for example, fully closed, and stop driving the solenoid valve 4o in response to the torque down-off signal to change the throttle valve to the opening set by the driver. Let the mag recover. Closing the throttle valve causes the engine rotational speed, that is, the rotational speed of the drive shaft 8 to decrease.

Therefore, during downshifting, the high speed clutch 27 is released and the low speed clutch 28 is engaged.

When shifting up, first the low speed clutch 28 is released, the engine speed is reduced, and then the high speed clutch 28 is released.
7 engages.

Next, the procedure of the control method according to the present invention executed by the control circuit wr35 will be explained according to the flowchart shown in FIG.

In this procedure, first, the engine rotation speed Ng.

Number of revolutions NIN of drive shaft 8: Number of revolutions N of output shaft 26. The output level of the brake switch 41 is read (step 80), and then it is determined whether the gear ratio of the sub-transmission 4 is at the high speed ratio (step 81).

This determination is performed until the high-speed clutch 27 is engaged by the generation of the high-speed clutch on signal, and when the gear ratio becomes the high speed ratio, the value is changed until just before the high-speed clutch off signal is generated, which releases the high-speed clutch 27. does not change, R
AM 670 Determined from the value of the shift flag using one address area.

If there is a high speed brake, it is determined whether the brake switch 41 is on (step 82).

When the foot brake is depressed and the brake switch 41 is on, the read throttle valve opening θth
Determine whether or not the opening is fully closed (step 8'3)
. If the throttle valve is in the fully closed state, it is further determined whether or not this state has continued for a predetermined time TBR.Step 8
4) If TBR continues for a predetermined period of time, it is assumed that the engine is in deceleration operation, and whether or not the read engine rotation speed N is below the predetermined rotation speed NBR (for example, 2000 to 3000 de, p, m,). Step 85), Ne<NB
In the case of R, a high speed clutch off signal and a low speed clutch on signal are generated to perform downshift processing to a low speed ratio (step 86).

In step 81, if it is determined that the ratio is not a high speed ratio, the ratio is a low speed ratio, and this state is continued. Further, if the brake switch is turned on in step 82, if the throttle valve is opened in step 83, if the time is less than TBR in step 84, and if Na≧NBR in step 85, running at a high speed ratio is continued.

Now time 1. Assume that deceleration driving is started by the driver's foot brake operation, and the engine speed and vehicle speed begin to decrease. Further, the rotation speed of the input shaft, that is, the drive shaft 8 of the Ill transmission 11-4 is NIN''l, the rotation speed of the medium power shaft 26 is N.The UT high speed ratio is 1''1%, and the low speed ratio is r2. The rotational speed N1N before downshifting is N. UT"1. If the rotational speed of the drive shaft 8 after downshifting is NIN/t, then NINI=N・de2 holds. Therefore, when downshifting is performed, the rotational speed at the time of downshifting is N.UT
& Kaoru are equal, so NIN/ == (r2nde,) NI
N holds true. Since f2/71 is, for example, 0.5, the downshift is performed at time t3 when the engine speed NIN is lower than at time t2 as shown in FIG. 5 and the engine speed N- is smaller than the predetermined engine speed NBR. The difference ΔN=NIN'-NIN from the rotational speed NId' becomes smaller. Sunawachi engine output torque change becomes smaller,
It also reduces shift shock.

In the embodiment of the present invention described above, the fully closed determination of the throttle valve in step 83 is provided to distinguish between a deceleration downshift and an acceleration downshift, but it is not essential. Further, the high speed ratio in step 81 may be determined by detecting the vehicle speed and the engine rotational speed and dividing the vehicle speed by the engine rotational speed.

As described above, according to the automatic transmission control method of the present invention,
Since the downshift is performed when the engine output torque change before and after the gear shift is small, shift shock during deceleration operation can be reduced.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing the power transmission system of an automobile according to the present invention, FIGS. is a block diagram showing the control circuit of the auxiliary transmission in the power transmission system of Fig. 1, Fig. 4 is an operation flow diagram of the control circuit showing the control method according to the present invention, and Fig. 5 is an application of the control method according to the present invention. FIG. 3 is a diagram showing the operation of the auxiliary transmission. Explanation of symbols for main parts 1... Engine 2... Clutch 3... Manual □ Transmission 4... Sub-transmission 6... Clutch shaft 8... Drive shaft 21... Sangya 22. ... Planetary carrier 23 ... Planetary pinion 24 ... Ring gear 25 ... One-way clutch 26
...Output shaft 27...High speed clutch 28...
・Low speed clutch 31.32...Hydraulic circuit 33.34
, 40... Solenoid valve 35... Control circuit applicant Honda Motor Co., Ltd. agent Patent attorney Motohiko Fujimura 15- and Banbakoki

Claims (2)

[Claims] (1) A method for controlling an automatic transmission that is supplied with rotational power from an on-vehicle internal combustion engine and has at least two gear ratios, wherein the gear ratio is at least one of the two high speed ratios and the operating brake is in operation. , detects the engine speed at the time of detection, and performs a downshift to the other low speed ratio of the gear ratio when the engine speed falls below a predetermined speed. Method. (2) The control method according to claim 1, wherein the downshift is performed when the operated brake is in operation for a predetermined period of time.