JPS60139957A - 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 a car speed is below a prescribed speed 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, an engine revolution-angle sensor, etc. are connected to the control circuit. When the speed change ratio is within a high-speed ratio in the control circuit, the car-speed is detected, and the solenoid valves 33 and 34 are controlled so that the shift-down to a low-speed ratio is performed when the car- speed is below a prescribed speed and 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.

In an automatic transmission, it is necessary to downshift when the vehicle speed is decreasing while driving at a high ratio.

If the downshift timing is not set properly, engine knocking may occur before the downshift.
This has the disadvantage that drivability deteriorates before and after downshifting.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for controlling an automatic transmission that prevents knocking during downshifting and improves drivability.

The automatic transmission control method of the present invention is characterized by downshifting to a low speed ratio when the vehicle speed is below a predetermined speed and the engine speed is below a predetermined speed when the automatic transmission is in a high speed ratio. Embodiments of the present invention will be described below 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 the engine 1 is transmitted through a clutch 28, manual transmission 3. Then, through the sub-transmission 4, the wheels [
(not shown)]. The flange 21, manual transmission 3, and auxiliary transmission 4 are integrally formed with a case 5vc. The manual transmission 3 includes a clutch shaft 6, a counter shaft 7, a drive shaft 8. Clutch gear9. Counter gear 10 to 14. Third speed gear 15. Second speed gear 16. First speed gear 17
It is a synchronous mesh type transmission with 4 forward speeds and 1 reverse speed, consisting of synchronizers 18, 19, reverse gear 20, etc.

The sub-transmission 4 has a sun gear 21. Planetary carrier 22.
It is a two-stage automatic I-speed machine of planetary gear type using a planetary pinion 23 and a ring gear 24.

The sun gear 21 is rotatably provided on a drive shaft 8 that is the output of the manual transmission 3, and the planetary carrier 22 is fixed to the drive shaft 8 that forms a shaft that enters the sub-transmission 40. A plurality of planetary pinions 23 meshed with the sun gear 21 are made rotatable by a planetary carrier 22, and a ring gear 24 meshed with each of the zero planetary pinions 23 located at equal intervals from each other is driven via a one-way clutch 25. It is connected to the shaft 8 and fixed to the 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 sun gear 21Jy and the high-speed clutch 27 are fixed to the case 5, and the rotational power of the drive shaft 8'' is transmitted to the output shaft 26 via the planetary carrier 22, planetary pinion 23, and ring gear 24, and is increased. 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 and are in a direct connection state, so that the speed ratio changes. is set to a low speed ratio.

3- As shown in FIG. 2, pressure oil is supplied from the oil pressure i30 to the high-speed clutch 27 via a hydraulic passage 31, and pressure oil is supplied to the low-speed clutch 28 via a hydraulic passage 32 branched from the hydraulic passage 31. be done. A solenoid valve 33 is provided downstream of the branch point J:"Q of the hydraulic passage 31 to the hydraulic passage 32, and a solenoid valve 34 is also provided at the oil cliff passage 32. Solenoid valve 3
When the solenoid 33α of No. 3 is de-energized, the valve body 33h moves to the left in the figure by the biasing force of the spring 33C to block the hydraulic passage 31, and when the solenoid 33α is energized, the valve body 33h By moving to the right in the figure against the biasing force, the extraction pressure passage 31 is brought into communication.

Further, when the solenoid 34α of the solenoid valve 34 is de-energized, the valve body 34h moves to the left in the figure by the biasing force of the spring 34c to communicate with the hydraulic passage 32, and the solenoid 34α
When energized, the valve body 34α moves to the right in the figure against the biasing force of the spring y34c, thereby closing the oil passage 32. Energization/de-energization of the solenoid valve 33.3;1 is controlled by a control circuit 35, which will be described later.

4- As shown in Fig. 3, the control circuit 35 includes an engine rotation angle detection sensor 36 that generates a 33° position signal for the solenoid valve, and a human rotation sensor 36 that generates an angular position signal with a period proportional to the drive shaft 80 rotation speed. An angle detection sensor 37, an output rotation angle detection sensor 38 that generates an angular position signal with a period proportional to the rotation speed of the output shaft 26, and a throttle that generates an output voltage according to the opening degree of a throttle valve (not shown). An opening sensor 39 and a solenoid valve 40 that forcibly closes the throttle valve described above to reduce the engine speed.
are connected. Engine rotation angle detection sensor 361
Human rotation angle detection sensor 37 and output rotation angle detection sensor 3
8 is of a magnetic detection type consisting of a permanent magnet and a magnetic detection element.

The control circuit 35 includes waveform shaping circuits 51 to 53, each of which is provided corresponding to the rotation angle detection sensor 36 to 38, and which shapes the angular position signal into a seven-string pulse signal, and generates the output pulse of the waveform shaping circuit 51. M, counter 55, and waveform shaping circuit 5, which measure clock pulses counted at intervals to generate a digital signal representing the engine rotation speed.
The NIN counter 56 generates a digital signal representing the number of revolutions of the drive shaft 8 by measuring clock pulses counted at the interval of generation of the output pulses of the waveform shaping circuit 53, and the clock pulses counted at the interval of generation of the output pulses of the waveform shaping circuit 53. N which measures the clock pulse and generates a digital signal representing the rotational speed of the output shaft 26; UT counter 5
7, a level correction circuit 59 that corrects the output level of the throttle opening sensor 39, and an A/D converter 61 that converts the output voltage of the level correction circuit 59 into a digital signal.
, a drive circuit 62 to 64 for each of the solenoid valves 33, 34, and 40, a CPU 65, a ROM 66 in which various processing programs and the gear ratio of the sub-transmission 4 are stored, R, A
M67, and counters 55 to 57. A
/D converter 61. Drive circuit 62 to 6'4, C
PU6 s , ROM 66 and RAM 67 are connected by a data bus line 68.

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

In such a configuration, the engine rotation speed N2. Drive shaft 80 rotations N1N
and the rotational speed N of the output shaft 26. UT, that is, vehicle speed data, and throttle valve opening data from the A/D converter 61 are sent to the CPU 6s via a pass line 68.
supplied to The CPU 65 reads each of the above data according to the calculation program stored in advance in the ROM 66,
Based on these data, it is determined whether the downshift condition or upshift condition of the sub-transmission 4 is satisfied.

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 33α 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.
Narrow down from 0! The hydraulic pressure is supplied to the high speed clutch 27 through the hydraulic passage 31 having the hydraulic pressure 1l131a, and the high speed clutch 27 is engaged. Further, 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 is discharged through the throttle f) 31h 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.

When the electromagnetic valve 34 is opened, pressure oil is supplied from the hydraulic source 30 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 932hf and the low-speed clutch 28 is released. The drive circuit 64 drives the solenoid valve 40 in response to the torque down-on signal, closes the throttle valve from the opening set by the driver to, for example, fully closed, and closes the solenoid valve 40 in response to the torque down-off signal. The drive of the throttle valve is stopped and the throttle valve is returned to the opening degree set by the driver. When the throttle valve closes, the engine rotational speed, that is, the rotational speed of the drive shaft 8, decreases.

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 side leg method according to the present invention executed by the side ear circuit 35 will be explained according to the flowchart of FIG.

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

Drive shaft 8 rotation speed NIN I output shaft 2
6 rotation speed N. The UT C vehicle speed VLt 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 just before the generation of the high-speed clutch-off signal, which is rewritten when the high-speed clutch 27 is engaged and the gear ratio becomes the high-speed ratio, and releases the high-speed clutch 27. its value does not change,
It is determined from the value of the shift flag using one address area of the RAM 67. If it is a high-speed ratio, the output shaft 260 rotation speed N is already read. UT, that is, the vehicle speed ■ is the predetermined speed ■. It is determined whether or not the following is true (step 82). If V<Vo, it is determined whether the read engine speed N is greater than or equal to a predetermined engine speed N (step 83). Predetermined rotation speed "mi"
U is the limit rotational speed at which there is no possibility of knocking occurring at a high speed ratio. If N, ≦N is 1, there is a possibility that knocking will occur, so a high-speed clutch-off signal and a low-speed clutch-on signal are generated to reduce the speed and downshift to γ-O (step 84
). If Ng >"min", it is determined whether the condition has continued for a predetermined time TSTD (Step 85), and if the condition has continued for a predetermined time TSTD, it is determined that drivability will deteriorate, and the process proceeds to Step 84 to perform a downshift process. do.

If it is determined in step 81 that the gear ratio is not a high speed ratio, the gear ratio is a low speed ratio, and this state is maintained. Further, if ■≧■o in step 82, and if time TSTD has not been reached in step 85, the vehicle continues running at the high speed ratio.

Note that in the embodiment of the present invention described above, step 8
Although the high speed ratio in 1 is determined based on the occurrence of a shift command signal such as a high speed clutch on signal, it may also be determined by detecting the vehicle speed and engine speed and dividing the vehicle speed by the engine speed.

In this way, according to the automatic transmission control method of the present invention, if the vehicle is running in one of the high speed ranges of at least two gear ratios and the vehicle speed and engine speed are low, the downshift will occur, resulting in knocking. In addition, even if the engine speed is high, if the vehicle continues to drive at a low speed for a predetermined period of time, it will shift down, which improves the effectiveness of the engine brake and improves drivability during subsequent acceleration. - It's Rui.

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram showing the power transmission system of an automobile related to this shield, Figure 2 is a schematic diagram showing the hydraulic circuit for high-speed and low-speed clutch operation in the power transmission system of Figure 1, and Figure 3 is 1st
FIG. 4 is a block diagram showing a control circuit for the auxiliary transmission in the power transmission system shown in FIG. Explanation of symbols of main parts l...Engine 2...Clutch 3:...Manual transmission 4...-1 transmission: Transmission 6...Clutch shaft 8...Drive shaft 21... Sun gear 22...Planetary carrier 23...Planetary pinion 24-...Ring gear 25...One-way clutch'
26... Output shirt 27... High speed clutch 28
...Low speed clutch 31', 32...Hydraulic passage 3
3.34.40... Solenoid valve 12-35... Control circuit applicant Honda Motor Co., Ltd. Agent Patent Attorney Motohiko Fujimura□ Hajime

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, which detects the vehicle speed when the gear ratio is at least one of the two high speed ratios. A control method characterized in that the vehicle speed is below a predetermined speed, the engine speed is detected, and when the engine speed is below the predetermined speed, a downshift is performed to the other low speed ratio of the gear ratio. (2) The control method according to claim 1, wherein the downshift is performed when the engine speed continues to be below the second predetermined speed for a predetermined period of time or more.