JPH04265431A - Output shaft torque control device for automatic transmission - Google Patents

Abstract

PURPOSE:To mitigate torque shock at speed changing in an automatic transmission having a torque convertor. CONSTITUTION:Based on engine operating condition detected by an operating condition detecting means 1 and gear ratio before and after speed changing of an automatic transmission detected by a gear ratio detecting means 2, the target torque of a transmission output shaft after speed changing is set by a target torque setting means 3, and the output shaft torque of the transmission detected by a torque detecting means 4 is approached to the above-stated target torque by feedback controlling ignition timing. When deviation between the target torque and the detected torque is over a prescribed value, fuel supply to a part of cylinders is stopped by a fuel supply cylinder number control means 5 at the same time of the above-stated ignition timing feedback control. Hereby, good output shaft torque control can be performed under all sorts of speed changing conditions, and torque shock at speed changing can possibly be mitigated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output shaft torque control device for feedback controlling output shaft torque during gear shifting of an automatic transmission by controlling engine torque.

0002

[Prior Art] Conventionally, as a shift shock reduction device when shifting to a high speed side in an automatic transmission for an automobile, the ignition timing of the engine is retarded to reduce the engine torque. There is a device that suppresses sudden changes in machine output shaft torque to alleviate shift shock (see, for example, Japanese Patent Application No. 1-325798).

[0003] In a conventional shift shock reduction device using such ignition timing retard control, a reduction request for engine output torque is generated when the throttle valve opening TVO at that time is within a predetermined range during a shift. In response to the occurrence of this torque down request, the ignition timing is retarded by a preset retard amount corresponding to the throttle valve opening range to reduce the engine output shaft torque and reduce the automatic transmission output shaft torque. It is designed to suppress torque changes.

0004

[Problems to be Solved by the Invention] However, in the conventional device, the ignition timing is not controlled based on the actual transmission output shaft torque during shifting, but the ignition timing is retarded by the throttle valve opening TVO during shifting. This is an open control system in which the angle amount is uniquely set, and the same retard amount is set for a throttle valve opening range having a certain range. Therefore, the transmission output shaft torque control accuracy during shifting is not sufficient, and the effect of reducing shift shock is not sufficient.

The present invention has been made in view of these conventional problems, and provides an output shaft that enables highly accurate feedback control of transmission output shaft torque by controlling two types of engine control with priority. An object of the present invention is to provide a torque control device.

[0006]

[Means for Solving the Problems] Therefore, an output shaft torque control device for an automatic transmission according to the present invention is configured to transmit engine torque to a transmission mechanism via a torque converter, as shown in FIG. The automatic transmission includes an operating state detection means for detecting the operating state of the engine, a gear ratio detection means for detecting the gear ratio of the automatic transmission, and an engine operating state detected at the start of shifting and the gear ratio before and after shifting. a target torque setting means for setting a target torque of the transmission output shaft after shifting based on a target torque, a torque detection means for detecting the torque of the transmission output shaft, and a set target torque of the detected transmission output shaft. ignition timing feedback control means for feedback controlling the ignition timing of the engine so as to bring it closer to the torque, and supplying fuel to some cylinders in parallel with the ignition timing feedback control when the deviation between the target torque and the detected torque is greater than a predetermined value. The present invention includes fuel supply cylinder number control means for stopping fuel supply.

Furthermore, the fuel supply cylinder number control means may be configured to control the number of cylinders to which fuel supply is stopped in a stepwise manner depending on the magnitude of the deviation between the target torque and the detected torque.

[0008]

[Operation] In such a configuration, when a shift request occurs,
Based on the engine rotational speed and throttle valve opening representative of the engine load detected by the operating state detection means, and the gear ratios before and after the shift detected by the gear ratio detection means, the output shaft of the transmission after the shift is determined. The target torque is set by target torque setting means.

On the other hand, the torque detection means detects the actual torque of the transmission output shaft, and the ignition timing control means feedback-controls the ignition timing of the engine so that the torque approaches the target torque. Further, when the deviation between the target torque and the detected torque is greater than a predetermined value, in addition to the ignition timing feedback control, the fuel supply cylinder number control means stops the fuel supply to some cylinders.

[0010] As a result, the transmission output shaft torque can be linearly controlled by the ignition timing control, and if the torque deviation cannot be eliminated by the ignition timing control alone, the fuel supply to some cylinders can be stopped. The responsiveness of feedback control can be maintained well. In this case, by controlling the number of cylinders to which fuel supply is stopped according to the magnitude of the torque deviation, it is possible to perform optimal torque feedback control for a wide range of torque deviations.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2 showing the configuration of this embodiment, an automatic transmission 2 is connected to the output side of the engine 1. automatic transmission 2
is a torque converter 3 interposed on the output side of the engine 1;
A gear type transmission 4 connected via this torque converter 3 and various speed change elements in this gear type transmission 4
and a hydraulic actuator 5 for performing a release operation. The hydraulic pressure applied to the hydraulic actuator 5 is ON/OFF controlled via various electromagnetic valves (not shown).

[0012] Signals from various sensors are input to the control unit 6. As the various sensors mentioned above, a throttle sensor 8 is provided which detects the opening degree TVO of the throttle valve 7 of the intake system of the engine 1. Further, a crank angle sensor 9 is provided on the crankshaft of the engine 1 or a shaft that rotates in synchronization with the crankshaft. The signal from the crank angle sensor 9 is, for example, a pulse signal for each reference crank angle, and the engine rotational speed N is calculated from the period thereof.

Further, a vehicle speed sensor 11 is provided which obtains a rotation signal from the output shaft 10 of the automatic transmission 2 and detects the vehicle speed VSP. Further, a torque sensor 12 is provided as a torque detection means that is attached to the output shaft 10 of the automatic transmission 2 and detects the output shaft torque T. The control unit 6 is, for example, an integrated type that incorporates a CPU for engine control (fuel injection control and ignition timing control) and a CPU for automatic transmission control, and uses a dual port RAM that is accessible from both CPUs. With this configuration, data calculated by both CPUs can be shared.

The automatic transmission control CPU of the control unit 6, when the select lever is in the D range, based on the operation position signal of the select lever operated by the driver,
1st speed ~ according to throttle valve opening TVO and vehicle speed VSP
A shift position of the fourth speed is automatically set, and shift control is performed to control the gear type transmission 4 to that shift position via the hydraulic actuator 5.

Next, the control operation of the transmission output shaft torque during gear shifting according to this embodiment will be explained with reference to the flowcharts shown in FIGS. 3 and 4. In this embodiment, the functions of gear ratio detection means, target torque setting means, ignition timing feedback control means, and fuel supply cylinder number control means are provided in software as shown in the flowcharts of FIGS. 3 and 4. It is being

First, step 1 (denoted as S1 in the figure,
(The same applies hereafter), determine the value of a control start flag F, which will be described later. If it is 0, proceed to step 2, but if it is 1, proceed to step 5, and measure the elapsed time after the start of the gear change operation, which will be described later. It is determined whether the value of the timer T has reached a target shift time t set as described later. When the shift has been reached, it is determined that the shift has been completed and step 6 is reached.
After resetting the flag F to 0, this control is ended,
If it has not reached the level, it means that the gear is being shifted, so proceed to step 7 and set the basic control amount RETIN in ignition timing control, which will be described later.
Δ
Update with the added value of RETIN (>0).

In step 2, the start of the speed change operation (inertia phase) is determined. For example, the output shaft torque of the transmission suddenly decreases when the clutch is released at the start of a shift, and then rapidly increases when the clutch starts to be engaged, so the torque change can be detected and determined. If it is determined in step 2 that the shift operation has not started, the flag F is 0, so the shift is not in progress, and this routine is ended.

When it is determined in step 2 that the shift operation has started, in step 3 the control start flag F is set to 1 and the timer T is reset to 0, and then the process proceeds to step 4 where the initial value of the basic control amount RETIN and the initial value of the basic control amount RETIN are set. Target shift time t
Set. These values are determined by the throttle valve opening and the type of gear change (1st gear → 2nd gear, 2nd gear → 3rd gear, etc.) as shown in Figure 5.
By searching from a map in which the initial value of the basic control amount RETIN is set based on the gear ratio GR (=Ga/Gb) obtained from the pre-shift gear ratio Gb and the post-shift gear ratio Ga according to Set.

After passing through step 4 or step 7, the process proceeds to step 8. In step 8, a target torque TRQREF of the transmission output shaft is set. Specifically, based on the gear ratio before and after the shift and the engine rotation speed N, the engine rotation speed N after the shift is determined when the vehicle speed is kept constant, and the engine rotation speed N when the throttle valve opening is also kept constant. The torque is determined by searching from a map as shown in FIG. Incidentally, the gear ratio before and after the shift is determined from the pattern of the shift positions of 1st to 4th speeds, which are set according to the throttle valve opening TVO and the vehicle speed VSP. Therefore, the gear ratio detection means includes a map in which the shift position pattern is set, and a search function from the map. The function of step 8 constitutes target torque setting means.

In step 9, the deviation TRQER between the output shaft torque TRQ of the transmission detected by the torque sensor 12 and the target torque TRQREF set in step 8 is determined.
Calculate R (=TRQ-TRQREF). In step 10, a value CUTCYL indicating the number of cylinders to which fuel supply is stopped in the fuel supply cylinder number control performed in parallel with the ignition timing control during gear shifting according to the present invention is reset to zero.

In step 11, it is determined based on the value of the output mixture ratio correction coefficient KMR whether or not the high output range is appropriate for controlling the number of cylinders to which fuel is supplied. And KMR=
In areas other than the high output area where KMR is 0, the process jumps to step 15 and executes ignition timing control without performing fuel supply cylinder number control, but in the high output area where KMR≠0, the process proceeds to step 12.

In step 12, the deviation TQRERR calculated in step 9 and a predetermined reduced torque amount TRQDW are calculated.
Compare with N. And TQRERR>TRQDWN
In this case, it is determined that the torque deviation is large enough to increase the number of cylinders to which fuel supply is stopped, and the process proceeds to step 13.
Step 14 after counting up the value of UTCYL
The torque amount TD1CY is estimated to decrease when the number of fuel supply stopped cylinders is increased by 1 from the deviation TQRERR.
After updating the deviation TQRERR with the value obtained by decreasing L, the process returns to step 12 and the same determination is made again. In this way, when TQRERR≦TRQDWN, step 1
Proceed to step 5 to execute ignition timing control. Here, the functions of steps 12 to 14 constitute fuel supply cylinder number control means.

[0023] In step 15, ignition timing (retard amount)
The control amount RETAT is calculated according to the following equation. RETAT=Kp ・TRQERR+Ki ∫TR
QERR +KD ・d/
dt (TRQERR) +RETIN In other words, based on the basic control amount as the feedforward component, the proportional component Kp
・TRQERR, integral Ki ∫TRQERR, differential KD ・Feedback control is performed using a correction amount that adds d/dt (TRQERR), and by giving the basic control amount in this way, the responsiveness can be improved from the start of shifting. Since good ignition timing control can be performed, shift shock can be reduced as much as possible (see Fig. 7).

Further, while the output shaft torque is linearly controlled by ignition timing control, if the torque deviation TRQERR cannot be eliminated in a short time by the ignition timing control alone, the torque deviation TRQERR may be controlled depending on the magnitude of the deviation TRQERR. By performing control to gradually increase the number of cylinders to which fuel supply is stopped,
Torque feedback control can be performed with good responsiveness to a wide range of torque deviations.

Furthermore, the basic control amount RETIN is set at step 7.
The torque is gradually increased as the time elapsed after the shift increases, and as a result, the torque change from before the shift to after the shift is gradual, and the shift shock reduction effect can be further enhanced. In step 16, it is determined whether this is the first time that the feedback control of the ignition timing has been executed (for example, this can be determined based on whether the control start flag F has changed from 0 to 1).
.

When it is determined that this is the first time, the process proceeds to step 17, where the basic control amount RETIN stored in the map under the same conditions is updated using the control amount RETAT set in step 15. If it is determined that it is the second or subsequent time, the process jumps to step 17 and proceeds to step 18. In this way, by learning and correcting the initial value of the basic control amount to a value that corresponds to the initial feedback control result, the correlation between the engine rotation speed N and the target torque TRQREF deviates due to changes in the clutch friction coefficient, etc. over time. Even in such cases, good feedback control performance can be maintained by modifying the basic control amount.

In step 18, fuel supply to the number of cylinders indicated by CUTCYL is stopped. However, when it is 0, there are no cylinders to which fuel supply is stopped. In other words, ignition timing control is executed with priority over control of the number of fuel supply cylinders. In step 19, the control amount R set in step 15 is
Only ETAT retards the ignition timing.

Here, the functions of step 9, step 15, and step 19 constitute ignition timing feedback control means.

[0029]

As described above, according to the present invention, when controlling the engine torque to bring the transmission output shaft torque closer to the target value during gear shifting, ignition timing feedback control is performed to linearly adjust the output shaft torque. While performing high-precision control by changing the torque, it also performs control to stop fuel supply to some cylinders even when the torque deviation is large, making it possible to perform responsive feedback control from the beginning of the gear shift. It is possible to enhance the gear shift shock reduction effect.

Furthermore, by controlling the number of cylinders to which fuel supply is stopped in stages according to the torque deviation, it is possible to cope with a wide range of torque deviations, thereby reducing shift shock as much as possible under all shift conditions. The effect can be increased.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the configuration of the present invention.

FIG. 2 is an overall system configuration diagram of an embodiment of the present invention.

FIG. 3 is a flowchart of a torque control routine of the embodiment.

FIG. 4 is a flowchart of a torque control routine according to the embodiment.

FIG. 5 is a map of the basic control amount of ignition timing in the embodiment.

FIG. 6 is a diagram illustrating setting of target torque in the embodiment same as above.

FIG. 7 is a time chart showing the characteristics during shifting of the embodiment.

[Explanation of symbols]

1. Institution 2 Automatic transmission 3 Torque converter 6 Control unit 8 Throttle sensor 9 Crank angle sensor 10 Transmission output shaft 12 Torque sensor

Claims (2)

[Claims] 1. An automatic transmission configured to transmit engine torque to a transmission mechanism via a torque converter, comprising: operating state detection means for detecting the operating state of the engine; and a gear ratio before and after shifting of the automatic transmission. gear ratio detection means for detecting the gear ratio, target torque setting means for setting the target torque of the transmission output shaft after the shift based on the engine operating state detected at the start of the shift and the gear ratio before and after the shift; a torque detection means for detecting the torque of the shaft; an ignition timing feedback control means for feedback-controlling the ignition timing of the engine so that the detected torque of the transmission output shaft approaches a set target torque; and said target torque and detection means. An automatic transmission comprising fuel supply cylinder number control means for stopping fuel supply to some cylinders in parallel with ignition timing feedback control when the deviation from the torque exceeds a predetermined value. output shaft torque control device. 2. The fuel supply cylinder number control means controls the number of fuel supply cylinders to be increased in stages according to the magnitude of the deviation between the target torque and the detected torque. 1. The output shaft torque control device for an automatic transmission according to 1.