JP3204009B2 - Engine torque control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine torque control device for a vehicle engine combined with a transmission.

[0002]

2. Description of the Related Art In a vehicle, when an accelerator pedal is depressed, the throttle opening shifts from a low opening including a fully closed state to a high opening in a stepwise manner, particularly from a fuel cut-off state to an acceleration state (fuel injection state). For example, when the operation shifts to ()), vibration (so-called jerky vibration) occurs in the vehicle longitudinal direction due to the natural vibration of the drive system due to the input of the step torque to the drive system.

For this reason, conventionally, Japanese Patent Application Laid-Open No. 56-9856
As shown in Japanese Patent Application Laid-Open No. 9-209, the engine torque is reduced by delaying the ignition timing for a predetermined time (or while the engine is rotating at a predetermined speed) at the time of detecting the acceleration, thereby making the rise of the engine torque smoother. , Jerky vibration is suppressed.

[0004]

However, such a conventional engine torque control device has the following problems because it is configured to reduce only the rattling vibration at the start of acceleration. During acceleration, the engine torque increases as the throttle valve opens,
Slightly later, the transmission downshifts according to the shift schedule. Therefore, when shifting (downshift) of the transmission is completed, a thrust torque corresponding to the inertia of the engine rotation is generated, which causes a problem that rattling vibration is generated.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to suppress rattling vibrations at the end of downshifting due to acceleration.

[0006]

Therefore, in the invention according to claim 1 , as shown in FIG. 1 , an acceleration detecting means for detecting the acceleration of the engine, and a transmission of the transmission accompanying the detected acceleration are provided.
To detect the shift speed immediately before the end of the shift to the downshift side.
Speed detection means, shift end detection means for detecting the end of the shift of the transmission to the downshift side due to the detected acceleration, and when the shift speed immediately before the end of the shift is equal to or higher than a predetermined value
And an engine torque reducing means for temporarily reducing the engine torque by detecting the end of the shift, to constitute an engine torque control device.

[0007]

Further, in the invention according to claim 2 , the engine torque reducing means calculates the amount of reduction of the engine torque in accordance with the shift speed immediately before the end of the downshift of the transmission due to acceleration. It is characterized by having. Furthermore, the invention according to claim 3 is characterized in that the engine torque reducing means reduces engine torque by retarding the ignition timing for the engine.

[0009]

According to the first aspect of the present invention, when the acceleration of the engine is detected and the end of the downshift of the transmission accompanying the acceleration is detected, the shift speed immediately before the end of the shift is set to the predetermined value.
Only in the above case, the engine torque is temporarily reduced after the shift end is detected. As a result, it is possible to suppress rattling vibration caused by pushing up the inertia torque of the engine rotation at the end of the shift.

[0010] In this case, because when the transmission speed immediately before the shift end is small, less vibration at the time of the shift end, the transmission end
Only when the shift speed immediately before the end is high, the engine torque is reduced to suppress the vibration.

According to the second aspect of the present invention, when the engine torque is reduced, the engine torque reduction amount is calculated according to the shift speed immediately before the end of the shift, so that the engine torque reduction amount is adjusted in accordance with the generated vibration. Can be optimally controlled. In the invention according to claim 3 , since the engine torque is reduced by retarding the ignition timing for the engine, the engine torque can be reduced with simple control.

[0012]

An embodiment of the present invention will be described below. FIG. 2 shows a system configuration. A throttle valve 3 interlocked with an accelerator is provided in an intake passage 2 of the engine 1 to control an intake air flow rate.

An auxiliary air passage 4 is provided bypassing the throttle valve 3, and an electromagnetic auxiliary air control valve 5 is provided in the auxiliary air passage 4 mainly for controlling idle speed. The opening of the auxiliary air control valve 5 is controlled by a duty signal from the engine control unit 8. An electromagnetic fuel injection valve 6 is provided at an intake manifold branch to each cylinder downstream of the throttle valve 3 in the intake passage 2. The fuel injection valve 6 is energized by a drive pulse signal output at a predetermined timing in synchronization with the engine rotation from the engine control unit 8 and opens to inject fuel adjusted to a predetermined pressure. Therefore, the fuel injection amount is controlled by the pulse width of the drive pulse signal.

Each cylinder of the engine is provided with an ignition unit 7, and these ignition units 7 perform an ignition operation according to an ignition signal from an engine control unit 8. For controlling the fuel injection valve 6, the ignition unit 7, and the auxiliary air control valve 5, the engine control unit 8 includes an air flow meter 9 for detecting an intake air flow rate Qa, an engine speed sensor 10 for detecting an engine speed Ne, and the like. , A detection signal is input.

On the other hand, a continuously variable transmission (CVT) 12 is provided on the output side of the engine 1 via a torque converter 11 with a lock-up clutch. Continuously variable transmission 12
Is the primary pulley on the engine side as shown in FIG.
13, a secondary pulley 14 on the drive shaft (diff) side, and a belt 15 wound between them, and a transmission pressure to the primary pulley side actuator 13a and a line pressure to the secondary pulley side actuator 14a. The gear ratio can be changed steplessly by adjusting the pulley ratio. However, another continuously variable transmission such as a toroidal type may be used, or a stepped transmission may be used.

The shift pressure and the line pressure are regulated by controlling the hydraulic pressure of a hydraulic circuit 17 connected to an oil pump 16 by solenoid valves 18 and 19 having a relief function. The solenoid valves 18 and 19 are controlled by an A / T control unit. Controlled by 20. Therefore, the A / T control unit 20 allows the solenoid valves 18 and
By controlling the transmission pressure and the line pressure by controlling 19, the transmission ratio can be controlled.

For controlling the gear ratio, an A / T control unit 20 includes a vehicle speed sensor 21 for detecting a vehicle speed VSP,
Detection signals are input from a throttle sensor 22 and the like for detecting the throttle opening TVO. The A / T control unit 20 sets the final target gear ratio GRf based on these signals with reference to a map based on the vehicle speed VSP and the throttle opening TVO, and sets the current gear ratio GR, the final target gear ratio GRf, and the like. If there is a difference between the target gear ratios GRt every moment based on the shift speed corresponding to this difference.
And set the solenoid valve 1 so as to obtain the target gear ratio GRt.
Shift control is performed by controlling 8 and 19. The A / T control unit 20 also controls the engagement and release of the lock-up clutch of the torque converter 11.

The engine control unit 8 and the A / T control unit 20 are connected by a communication line 23. In particular, the engine control unit 8 transmits the engine speed Ne to the A / T control unit 20.
Etc. can be transmitted, and the A / T control unit 20 sends the engine control unit 8
A request for reducing the engine torque (a request for retarding the ignition timing) can be transmitted to the engine.

FIG. 4 is a flowchart of an engine torque control routine executed by the A / T control unit 20 at a predetermined time interval (for example, 50 ms cycle) in connection with the present invention. In step 1 (shown as S1 in the figure, the same applies hereinafter), it is determined whether or not the vehicle is accelerating or immediately thereafter. Specifically, the previous throttle opening TVOold is subtracted from the current throttle opening TVO to obtain a throttle opening change amount ΔTVO = TVO−TVOold, which is compared with a predetermined value to obtain ΔTVO ≧ predetermined value In this case, it is determined that the vehicle is accelerating, and the process proceeds to step 2. If it is determined that the vehicle is accelerated, the process also proceeds to step 2 if the acceleration is within a predetermined time. Otherwise, this routine ends.

In step 2, the current gear ratio GR is detected by calculation from the vehicle speed VSP and the engine speed Ne. At this time, the gear ratio detected last time is stored and held as GRold. Note that the gear ratio in the present specification is defined as an input rotational speed / output rotational speed and, like the gear ratio, has a large value on the low side (low speed side) and a small value on the high side (high speed side). And

In step 3, the previous speed ratio GRold is subtracted from the current speed ratio GR to determine the speed (change in the speed ratio) ΔGR = GR−GRold. In step 4, it is determined whether the request is a downshift request. Specifically, the current gear ratio GR is compared with the final target gear ratio GRf (or the target gear ratio GRt), and GR <GRf (or G
If R <GRt), a downshift request is determined, and
Proceed to step 5. Otherwise, this routine ends.

In step 5, it is determined in accordance with the subroutine of FIG. The subroutine of FIG. 5 will be described. In step 51, the final target gear ratio GRf
It is determined whether the deviation (GRf-GR) between the current speed ratio GR and the current gear ratio GR is equal to or less than a predetermined value. In step 52, it is determined whether the shift speed ΔGR is equal to or less than a predetermined value. Where GRf
-If GR> predetermined value or ΔGR> predetermined value,
Proceeding to step 53, it is determined that the shifting has not been completed (the shifting is in progress).

Then, GRf-GR ≦ predetermined value and Δ
If GR ≦ predetermined value, the routine proceeds to step 54, where it is determined that the shift is completed. After the shift end determination, the process proceeds to step 6. In step 6, based on the above determination result, the process proceeds to step 7 if the shift has not been completed (during shifting), and proceeds to step 9 if the shift has been completed. [If the shift has not been completed] In step 7, the value of ΔGRm is updated with the current shift speed ΔGR so that the shift speed ΔGRm immediately before the end of the shift is stored (ΔGRm = ΔG).
R).

In step 8, in order to prepare for the initialization of the engine torque control, the flag F _DOWN = 0 is set, and this routine is terminated. [For the shift end] In step 9, in order to determine whether the shift completion after first processed, to check the value of the flag F _{DO WN,} only when the first time after the shift end, since it is F _DOWN = 0, Proceed to step 10. In the case of the second and subsequent times, this routine ends.

At step 10, the flag F _DOWN = 1 is set, and the routine proceeds to step 11. In step 11, the shift speed ΔGRm immediately before the end of the shift, which is stored and held, is read, and it is determined whether or not this is a predetermined value or more. The predetermined value here is set based on the engine speed Ne, the vehicle speed VSP (or the speed ratio GR), and the like. If ΔGRm ≧ predetermined value, it is expected that a torque step will occur. Therefore, in order to execute the torque reduction control, in step 12 proceeding to steps 12 and 13, based on the shift speed ΔGRm immediately before the end of the shift, this The torque reduction amount ΔT = f (ΔGRm) is calculated so as to be proportional.

In step 13, the ignition timing retard amount ΔADV is calculated in accordance with the calculated torque reduction amount ΔT, and the retard amount ΔADV is sent to the engine control unit 8.
An ignition timing delay request signal corresponding to the ADV is output, and the ignition timing is delayed in a predetermined pattern for a predetermined time. If ΔGRm <predetermined value, it is determined that the generated torque step is small and the torque reduction control is unnecessary, and this routine is terminated as it is, and the ignition timing is not retarded.

In this embodiment, step 1 corresponds to acceleration detecting means, steps 4 to 6 correspond to shift end detecting means, and steps 2, 3 and 7 correspond to shift speed detecting means. Steps 11 to 13 correspond to engine torque reduction means. Next, the operation of the present embodiment will be described with reference to FIG. 6 by dividing into rapid acceleration (a) and gentle acceleration (b).

(A) In the case of rapid acceleration When rapid acceleration (a sharp increase in the throttle opening) is performed and the transmission is shifted to the downshift side in accordance with this acceleration, the inertia of the engine rotation after the shift is completed. Ragging vibration (part c in the drawing; large torque step) occurs due to the thrust-up of the torque. In the present embodiment, however, the lubricating vibration is temporarily reduced by retarding the ignition timing after the end of the shift to reduce the engine torque. Can be suppressed.

(B) Slow acceleration When the slow acceleration (slow increase of the throttle opening) is performed, the transmission is shifted to the downshift side in accordance with this acceleration. Is relatively small, and the torque step generated after the shift is completed is also small. Therefore, at this time, unnecessary control of retarding the ignition timing after the shift is completed is not performed.

Although omitted in the description of this embodiment, FIG.
As shown in the figure, at the time of acceleration detection, the engine torque is temporarily reduced by retarding the ignition timing for a predetermined period of time from the detection of acceleration, preferably until the start of shifting, as in the conventional example, to thereby temporarily reduce the engine torque. It goes without saying that the occurrence of rattling vibration is suppressed. In the present embodiment, the means for retarding the ignition timing is used as the engine torque reducing means. Alternatively, the means for reducing the fuel injection amount by the fuel injection valve 6 or the auxiliary air control valve 5 may be used instead. A means for reducing the amount of auxiliary air may be used, and in any case, control may be performed on the engine control unit 8 side in response to an engine torque reduction request from the A / T control unit 20. Further, when the throttle valve is electronically controlled without mechanically connecting the accelerator and the throttle valve, the engine torque is reduced by reducing the amount of air to the engine using the electronically controlled throttle valve. You may.

Further, in this embodiment, all downshifts associated with acceleration (or rapid acceleration) are targeted. However, a particular problem is with a continuously variable transmission and a lock-up clutch during deceleration. In a vehicle that is coasting with the drive system directly connected, it is a case of a downshift accompanying a restart of fuel injection from a fuel cut state due to depression of an accelerator, and thus control may be performed only in this case.

[0032]

As described above, according to the first aspect of the present invention, the engine torque is temporarily reduced at the end of the shift to the downshift side of the transmission due to the acceleration, so that the shift is completed at the end of the shift. As a result, it is possible to suppress the jerky vibration caused by pushing up the inertia torque of the engine rotation, thereby improving the drivability.

Further, the shift speed immediately before the end of the shift is equal to or less than a predetermined value.
Only when the engine torque is temporarily
By effectively reducing the speed, it is possible to prevent unnecessary control in a region where the shift speed immediately before the end of the shift is relatively slow and vibration at the end of the shift is small. Further, according to the second aspect of the present invention, the amount of reduction of the engine torque is calculated according to the shift speed immediately before the end of the shift, so that the amount of reduction of the engine torque can be optimally controlled in accordance with the generated vibration. Is obtained.

Further, according to the third aspect of the invention, an effect is obtained that the engine torque can be reduced by a simple control of retarding the ignition timing.

[Brief description of the drawings]

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

FIG. 2 is a system diagram of an engine showing an embodiment of the present invention.

FIG. 3 is a system diagram of the continuously variable transmission according to the embodiment.

FIG. 4 is a flowchart of an engine torque control routine of the embodiment.

FIG. 5 is a flowchart of a shift end determination subroutine of the embodiment.

FIG. 6 is a diagram showing the operation of the embodiment.

[Explanation of symbols]

 Reference Signs List 1 engine 2 intake passage 3 throttle valve 4 auxiliary air passage 5 auxiliary air control valve 6 fuel injection valve 7 ignition unit 8 engine control unit 11 torque converter 12 continuously variable transmission 13 primary pulley 14 secondary pulley 15 belt 17 hydraulic circuit 18, 19 Solenoid valve 20 A / T control unit 21 Vehicle speed sensor 22 Throttle sensor 23 Communication line

Continued on the front page (72) Noboru Hattori, Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture (72) Inventor Yusuke Minagawa 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa, Nissan Motor Co., Ltd. (56 References JP-A-64-85844 (JP, A) JP-A-5-263911 (JP, A) JP-A-63-105248 (JP, A) JP-A-5-147458 (JP, A) 56-98569 (JP, A) JP-A-63-61653 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 29/00 F02D 41/04 F02P 5/15

Claims (3)

(57) [Claims] In a vehicle engine combined with a transmission, acceleration detecting means for detecting acceleration of the engine, and shifting of the transmission to a downshift side in accordance with the detected acceleration.
A shift speed detecting means for detecting a shift speed immediately before the end; a shift end detecting means for detecting an end of a downshift of the transmission due to the detected acceleration; and a shift speed immediately before the end of the shift is a predetermined value. An engine torque control device comprising: an engine torque reducing unit that temporarily reduces engine torque by detecting the end of a shift in the above case. 2. The engine torque reduction means according to claim 1, further comprising means for calculating an engine torque reduction amount in accordance with a shift speed immediately before a shift downshift of the transmission accompanying the acceleration is completed. The engine torque control device according to claim 1 . Wherein said engine torque reduction means, according to claim 1 or請, characterized in that by retarding the ignition timing for the engine is to reduce the engine torque
Engine torque control device Motomeko 2 wherein.