JP2805710B2 - Shift shock reduction device for automatic transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a shift shock reducing device for an automatic transmission that controls engine output during shifting to reduce shift shock.

(Prior Art) In a recent automatic transmission, as shown in JP-B-63-14171, the engine output is reduced during gear shifting,
Many are designed to reduce shift shock.

(Problems to be Solved by the Invention) However, it has been found that it is not possible to sufficiently reduce the shift shock only by lowering the engine output during shifting.

This point will be described in detail by taking an example of an upshift. For a predetermined period from the start of shifting, a turbine speed, which is the input shaft speed of the automatic transmission, hardly changes, as is called a torque phase. Finally, the shift is ended after passing through a region in which the turbine speed greatly decreases due to a change in the gear ratio as called an inertia phase. The shift shock increases as the difference between the minimum torque and the maximum torque of the output shaft of the automatic transmission during the shift increases. In the above-mentioned torque phase, a considerable portion of the engine torque is consumed inside the automatic transmission (multi-stage transmission gear mechanism) due to the engagement of the frictional engagement element for shifting, so that the torque of the output shaft is reduced. It will tend to be quite depressed. Therefore, when the engine output is reduced during gear shifting, the output shaft torque of the automatic transmission is greatly reduced in the torque phase, which has been a major cause of insufficient reduction of gear shift shock. Such a phenomenon is not so remarkable as at the time of shift-up, but also occurs at the time of shift-down.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a shift shock reduction device for an automatic transmission, which can suppress a decrease in engine output in the torque phase and sufficiently reduce the shift shock.

(Structure and operation of the invention) In order to achieve the above object, the present invention has the following structure. That is, in a shift shock reduction device for an automatic transmission configured to reduce a shift shock by controlling an engine output during a shift, an output increasing unit that increases an engine output for a predetermined period from the start of a shift; Power reduction means for lowering the engine output, provided that the transmission torque is received by a transmission casing or a drive wheel via a one-way clutch. Is performed.

(Effects of the Invention) As described above, according to the present invention, it is possible to more optimally control the engine output at the time of shifting, and to further reduce shift shock. In particular, this is preferable in preventing a situation in which the engine is idling during shifting.

The configuration as described in claim 2 is preferable in that the torque phase is more accurately determined and the shift shock is more effectively reduced.

(Example) Hereinafter, an example of the present invention will be described with reference to the attached drawings.

1. Overall Overview In FIG. 1, E denotes an Otto type engine, and an output (torque) of the engine 1 is transmitted to an automatic transmission AT to drive wheels (not shown).

In the embodiment, the automatic transmission AT includes a torque converter 2 having a lock-up clutch, and a multi-speed transmission mechanism 10 having four forward speeds and one reverse speed. This automatic transmission AT is of a hydraulically operated type, and by switching between excitation and demagnetization of a solenoid 35 incorporated in the hydraulic circuit,
The lock-up clutch is interrupted. Further, by changing the combination of excitation and demagnetization of the plurality of solenoids 36 incorporated in the hydraulic circuit, a multi-speed transmission gear mechanism is provided.
Ten shifts are performed.

In FIG. 1, U is a control unit constituted by using a microcomputer.
While signals from .about.240 are input, the signals are output from the control unit U to the solenoids 35 and 36. At the same time, it is output to the igniter 40 for adjusting the ignition timing. The igniter 40 controls the primary current of the ignition coil 38, that is, the battery, at a timing corresponding to the ignition timing signal from the control unit U.
The current from 41 is cut off, and the high-pressure secondary current generated thereby is supplied to the spark plug 37 via the distributor 39.

The sensor 210 detects the throttle opening. The sensor 220 detects a vehicle speed. Sensor 230
Is for detecting the turbine speed. The sensor 240 detects the engine speed.

Configuration of Automatic Transmission FIG. 2 is a skeleton view schematically showing the automatic transmission AT.

In FIG. 2, reference numeral 1 denotes a crankshaft of an engine E which is an input shaft, and a torque converter 2 and a multi-speed transmission 10 are coaxially arranged with the crankshaft 1 in order from the engine side. The torque converter 2 includes a pump 3, a turbine 4, and a stator 5, and the pump 3 can be fixed to the crankshaft 1. Stator 5
Is connected to the multi-speed transmission 10 via the one-way clutch 6.
On the fixed shaft 7 integral with the case 11. The one-way clutch 6 allows the stator 5 to rotate in the same direction as the pump 3 but does not allow reverse rotation.

The multi-gear transmission 10 has a base fixed to the crankshaft 1 and a tip extending through the center of the multi-gear transmission to drive an oil pump P disposed on a side wall of the multi-gear transmission. , A central shaft 12 connected to the pump.
Outside the center shaft 12, a base end is connected to the turbine 4 of the torque converter 2, and a front end extends to the side wall of the multi-stage transmission 10 and is a hollow turbine rotatably supported on the side wall. A shaft 13 is provided. A Ravigneaux type planetary gear unit 14 is provided on the turbine shaft 13, and the planetary gear unit 14 has a small-diameter sun gear 15, a large-diameter sun gear 16 disposed on the side of the small-diameter gear 15 on the side far from the engine, It comprises a long pinion gear 17, a short pinion gear 18, and a ring gear 19.

Forward and coast clutches 20, 21 are provided on the side of the planetary gear unit 14 farthest from the engine E.
Are arranged in parallel. Forward clutch 20 above
Is a clutch for traveling forward, which interrupts power transmission between the small-diameter sun gear 15 and the turbine shaft 13 via the first one-way clutch 22. The coast clutch 21 interrupts power transmission between the small-diameter sun gear 15 and the turbine shaft 13 in parallel with the forward clutch 20. A 2-4 brake 23 is disposed radially outward of the coast clutch 21. The 2-4 brake 23 is a band brake, and has a brake drum 3-1 connected to the large-diameter sun gear 16 and a brake band 23-2 applied to the brake drum. A reverse clutch 24 is disposed radially outward of the forward clutch 20 and beside the 2-4 brake 23. This reverse clutch 24
Is a clutch for reverse running, and the above 2-4 brake
The large-diameter sun gear 16 is passed through the 23 brake drum 23-1.
And intermittent power transmission between the turbine shaft 13.

Outside the planetary gear unit 14 in the radial direction,
A low / reverse brake 25 is provided to tarnish the carrier 14a of the planetary gear unit 14 and the case 10a of the multi-speed transmission 10. A second one-way clutch 26 for disengaging the carrier 14a and the case 10a in parallel with the low reverse brake 25 is disposed between the brakes 23 and 25 between the above 2-4 and the low reverse brake. .
A 3-4 clutch 27 for intermittently transmitting power between the carrier 14a of the planetary gear unit 14 and the turbine shaft 13 is disposed beside the planetary gear unit 14 on the engine side. An output gear 28 connected to the ring gear 19 is disposed on the engine side of the 3-4 clutch 27, and the gear 28 is attached to an output shaft 28a. In the figure, reference numeral 2
Reference numeral 9 denotes a lock-up clutch for directly connecting the turbine shaft 13 and the crankshaft 1 to the torque converter 2.

The multi-stage transmission gear device 10 having the above-described structure has four forward speeds and one reverse speed by itself.
By appropriately operating the brakes 21, 24 and 27 and the brakes 23 and 25, a required gear can be obtained. Table 1 below shows the relationship between the gears and the operation of the clutch and brake in the above configuration. Of the clutches and brakes, only the 2-4 brake 23 (actuator) has two oil chambers, an apply side and a release side, as described later, to supply hydraulic pressure to the apply side and release the oil. Only when the hydraulic pressure on the side is released, the 2-4 brake 23 is engaged, and in other hydraulic supply modes, the 2-4 brake 23 is released. The remaining clutches and brakes (the respective actuators) each have only one oil chamber, and are engaged when oil pressure is supplied to the oil chamber, and the oil pressure in the oil chamber is released. Sometimes released.

Next, an outline of the shift control will be described with reference to FIGS. 3 and 4. FIG. In FIG. 3, among the characteristic lines indicating the output shaft torque, the solid line is according to the present invention, and the broken line is the conventional one (the engine output is reduced along the entire period from the start to the end of the shift).

First, FIG. 3 shows an example of an upshift.
The time t1 is the time when the shift command signal is generated. The engine output is controlled to increase from the time point t1 to a predetermined time period, that is, a time point t2 when the torque phase is reached. From t1 to t2
Up to the point, the turbine speed tends to be almost constant or slightly increased.

After the elapse of the time point t2, an inertia phase occurs, so that the engine output is reduced during this period. Then, at time t3 indicating the end of the shift, the engine output control for the shift is stopped, and the state is returned to the normal engine output.

In the embodiment, the control of the engine output at the time of shifting is performed by controlling the ignition timing. That is, when increasing the engine output, the ignition timing is advanced, and when decreasing the engine output, the ignition timing is retarded. At this time, the advance amount, the retard amount, that is, the increase / decrease amount of the engine output may be set with the engine load or the turbine speed as a parameter as shown in FIG. However, FIG. 4 shows the tendency of the increase / decrease amount of the engine output corresponding to the above-mentioned parameters, and the increase amount and the decrease amount of the engine output may be made different even with the same engine load.

The shift shock increases as the difference between the minimum value and the maximum value of the output shaft torque generated during the shift increases, but in the present invention, the difference can be reduced to further reduce the shift shock. .

Flow chart For details of the control by the control unit U, see FIG.
This will be described with reference to the flowchart shown in FIG.
In the following description, the case of shift up is taken as an example, and P indicates a step.

First, at P1, after signals from the respective sensors are read, at P2, it is determined whether or not to perform a shift in light of predetermined shift characteristics. Thereafter, in P3, it is determined whether or not the result of the determination in P2 is to perform a shift. When the determination in P3 is NO, that is, when shifting is not performed, the engine output control for shifting is not performed.
At 3, a normal engine output state is set.

When the determination in P3 is YES, that is, when shifting,
In 4, it is determined whether or not the shift mode is one in which the one-way clutch 22 or 26 in the multi-speed transmission 10 is involved. More specifically, in the embodiment, first to second speeds,
It is determined whether the gear is in any one of the first to third speeds, the first to fourth speeds, the second to fourth speeds, and the third to fourth speeds.
If the determination in P4 is N, that is, if it is not any of the five types of shift modes, the process proceeds to P13, and the engine output control according to the present invention is not performed. This is, for example, 2
When one friction element is released and the other friction element is engaged, as in the case of shifting from the fourth speed to the fourth speed, both of the friction elements are disconnected and a temporary It is said to prevent the occurrence of an excessive engine idling. In other words, the engine output increase according to the present invention is only performed when the engine torque is received by the drive wheels or the transmission casing via the one-way clutch 22 or 26 so that the engine does not run idle. Done.

When the determination in P4 is YES, in P5, it is determined whether or not the shift is completed (whether or not the time t3 in FIG. 3 has come). In this determination, it is determined whether or not the turbine rotation speed has become equal to or less than a predetermined rotation speed (the rotation speed theoretically obtained by the turbine rotation speed before the start of the shift and the shift before and after the shift). If the determination in P5 is YES, the flow shifts to P13.

If the determination in P5 is NO, it is determined in P6 whether or not it is in the torque phase. Specifically, the determination as to whether or not this is the torque phase is made when the change rate of the turbine speed is positive within a predetermined set time from the start of the shift (at time t1 in FIG. 3). It is determined that it is inside. The set time is set and stored in advance for each shift mode, for example, using the engine load as a parameter.

If the determination in P6 is YES, in P7, the T flag (torque phase flag) is set to 1 and the I flag (inertia phase flag) is set to 0.
Conversely, if the determination in P6 is NO, in P8, the T flag is set to 0 and the I flag is set to 1.

After P7 or P8, at P9, the T flag is set to 1
Is determined. If the determination in P9 is YES, in P10, the engine output is increased by advancing the ignition timing (engine output increase between t1 and t2 in FIG. 3).

If NO in the control of P9, after confirming that the I flag is 1 in P11, in P12, the engine output is reduced by retarding the ignition timing (third.
Engine output drop between t2 and t3). It should be noted that N
In the case of O, the flow shifts to P13.

The control of the ignition timing related to P10, P12 or P13 is performed based on the flowchart shown in FIG.

First, in P21, data on the engine speed of the engine load (throttle opening) and whether or not to perform engine output control for shifting are read.

In P22, as is known, the basic ignition timing θB is determined based on the engine speed and the engine load.
Thereafter, in P23, the ignition timing is corrected based on the engine cooling water temperature, the battery voltage, and the like, and the corrected ignition timing is determined as θCT0. A sensor for detecting data for this correction is not shown in FIG.

After P23, it is determined in P24 whether it is time to increase the engine output (determination of the presence or absence of an output up signal in P10 in FIG. 5). If the determination in P24 is YES,
In P28, the ignition timing retard amount + Δθ is determined (Δθ> 0). Then, in P29, a value obtained by adding the above + Δθ to the θC is determined as the final ignition timing θF (ignition is executed at the timing of θF).

If the determination in P24 is NO, it is determined in P25 whether it is time to reduce the engine output (fifth step).
Determination of the presence or absence of the output down signal at P12 in the figure). If the determination in P25 is YES, in P27, the ignition timing retard amount-
After Δθ (Δθ> 0) is determined, the flow shifts to P29.

If the determination in P25 is NO, the process goes through P13 in FIG. 5. In this case, since the increase / decrease control of the engine output is not performed, .DELTA..theta. Is set to 0 in P26, and the process proceeds to P29.

Although the embodiment has been described with reference to the case of upshifting, the present invention can be similarly applied to downshifting.

[Brief description of the drawings]

FIG. 1 is an overall system diagram showing one embodiment of the present invention. FIG. 2 is a skeleton diagram showing an example of a multi-speed transmission gear mechanism. FIG. 3 is a time chart schematically showing the control contents of the present invention. FIG. 4 is a diagram showing an example of how to set the increase or decrease of the engine output during gear shifting. FIG. 5 and FIG. 6 are flowcharts showing a control example of the present invention. U: Control unit E: Engine AT: Automatic transmission 10: Multi-speed transmission gear mechanism 20, 21, 24, 27: Friction fastening element 22, 26: One-way clutch 35: Shift solenoid 37: Spark plug

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FIF16H 63:12 (56) References JP-A-1-305138 (JP, A) JP-A-62-194939 (JP, A) JP-A-62-221934 (JP, A) JP-A-62-198529 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16- 61/24 F16H 63/40-63/48

Claims (2)

(57) [Claims] 1. A shift shock reduction device for an automatic transmission, wherein the shift output is reduced by controlling an engine output during a shift, wherein an output increasing means for increasing an engine output for a predetermined period from the start of a shift; An output reducing means for reducing the engine output after a lapse of a period, provided that the engine torque is received by a transmission casing or a drive wheel via a one-way clutch, and the engine is increased by the output increasing means. A shift shock reduction device for an automatic transmission, wherein output is increased. 2. The system according to claim 1, wherein the increase of the output of the engine by the output increase means is performed within the predetermined period from the start of the shift and when the rate of change of the turbine speed is positive. A shift shock reducing device for an automatic transmission, characterized in that: