JP3034287B2 - Transmission control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a shift control of an automatic transmission during a shift-up shift at the time of returning an accelerator (that is, a shift-up shift is caused by a decrease in engine load). It concerns the device.

2. Description of the Related Art Generally, an automatic transmission mounted on an automobile combines a torque converter and a transmission gear mechanism, and selectively operates a power transmission path of the transmission gear mechanism by a plurality of frictional engagement elements such as clutches and brakes. And automatically shifts to a predetermined gear. Japanese Patent Application Laid-Open No. Sho 62 (1987) discloses a shift control device for this type of automatic transmission.
What is described in -137451 is publicly known.

And in an automobile equipped with this kind of automatic transmission,
Upshifting when the accelerator is released (for example, 3-
If the shift according to the normal shift schedule is performed with respect to (4 shift-up), since the engine rotation has not yet sufficiently decreased, a thrust up shock due to the release of the rotational energy may occur. Therefore, after the accelerator is returned, the shift command is delayed for a predetermined time, so that the shift is performed in anticipation of a situation in which the engine rotation is reduced and a thrust shock is difficult to occur. That is,
As shown in FIG. 3 (a), when a gear shift instruction is given at point A and the accelerator is released, the engine speed Ne decreases and the turbine speed Nt as shown in FIG. There is a configuration in which the shift instruction output is delayed until a time point B when the state shifts to a lower state (that is, a reverse drive state), thereby preventing a thrust-up shock at the time of shifting.

(Problems to be Solved by the Invention) However, as shown in FIG. 3 (b), depending on the accelerator opening when returning the accelerator (in other words, the throttle opening) when there is a shift instruction at point A, There is a case where the engine speed Ne does not decrease so much and does not shift to a state where the engine speed Ne becomes lower than the turbine speed Nt (that is, a reverse drive state). In such a case, even if the shift instruction output is delayed as described above, the effect of reducing the shift shock is not obtained, and a problem occurs that the shift timing is unnecessarily delayed.

The present invention has been made in view of the above points, and by controlling a shift instruction output in accordance with whether or not a shift-up shift at the time of returning an accelerator is a shift to perform a deceleration shift,
It is an object of the present invention to reduce shift shock during deceleration transition and prevent unnecessary shift delay.

(Means for Solving the Problems) In the present invention, as means for solving the above problems,
In an automatic transmission including a torque converter and a gear transmission mechanism, a shift is performed by reducing the engine load detected by the engine load detecting means for detecting the engine load, the vehicle speed detecting means for detecting the vehicle speed, and the engine load detecting means. When an upshift occurs, the shift is to shift to a deceleration state when the engine load detected by the engine load detecting means is smaller than a predetermined engine load defined based on the vehicle speed detected by the vehicle speed detecting means. If the deceleration transition determining means determines that the shift is to be decelerated and shifted, a command to delay the shift for a predetermined time is output to the automatic transmission. If it is determined that the shift does not shift, the automatic transmission is immediately shifted. And a shift control means for outputting a can command.

(Operation) In the present invention, the following effects can be obtained by the above means.

That is, when an upshift is caused by a decrease in the engine load, and the engine load detected by the engine load detection means is smaller than a predetermined engine load defined based on the vehicle speed detected by the vehicle speed detection means. It is determined that the shift is a shift that shifts to a deceleration state. In that case, a shift instruction output is issued with a delay of a predetermined time, whereas if not a shift that shifts to a deceleration state, a shift instruction output is immediately issued. It is supposed to be.

(Effects of the Invention) According to the present invention, in an automatic transmission equipped with a torque converter and a gear transmission mechanism, an engine load detecting means for detecting an engine load, a vehicle speed detecting means for detecting a vehicle speed, and an engine load detecting means. When an upshift is caused by a decrease in the detected engine load, the engine load detected by the engine load detection unit is smaller than a predetermined engine load defined based on the vehicle speed detected by the vehicle speed detection unit. And a command to delay the shift to the automatic transmission by a predetermined time if the shift is determined to be decelerating by the decelerating shift determining means. Is output, and when it is determined by the deceleration shift determination means that the shift is not in deceleration shift, the automatic Shift control means for outputting a command to immediately change the speed of the transmission, and in a case where an upshift is caused by a decrease in engine load, the speed is determined based on the vehicle speed detected by the vehicle speed detection means. When the engine load detected by the engine load detecting means is smaller than the predetermined engine load, it is determined that the shift is a shift to shift to a deceleration state. In that case, a shift instruction output is output with a delay of a predetermined time. When the shift is not a shift to the deceleration state, the shift instruction output is immediately output, so that the shift to the deceleration is accurately detected, so that the shift shock during the shift to the deceleration can be reduced and unnecessary shift delay can be reduced. There is an excellent effect that compatibility with prevention can be achieved.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 2 shows a drive system A of an automobile as an application example of the present invention.
Where 1 is an engine, 2 is an automatic transmission,
3 is an intake pipe, 4 is a drive shaft, 5 is a differential gear, 6
Is the rear wheel.

The drive system A is provided with an engine control unit 7 for controlling the engine and an AT control unit 8 for controlling the automatic transmission. Both control units 7, 8 are constituted by, for example, microcomputers.

The engine control unit 7 receives the rotation speed Ne of the engine 1 and the negative pressure Tvo in the intake pipe 3,
The T control unit 8 receives the rotation speed Nt of the turbine in the automatic transmission 2 and the vehicle speed V. The AT control unit 8 outputs a shift instruction signal Rs (t) to the automatic transmission 2. The engine control unit 7 may receive an intake air amount Av instead of the intake pipe negative pressure Tvo.

The engine speed Ne and the intake pipe negative pressure Tvo (or the intake air amount Av) are transmitted from the engine control unit 7 to the AT control unit 8 as information communication.

As shown in FIG. 1, the AT control unit 8 determines whether or not the shift to shift to the deceleration state occurs when an upshift is caused by a decrease in the engine load (that is, in the case of a backout shift). And the automatic transmission 2 when the shift is determined to be a deceleration shift by the deceleration shift determination means 11.
And a command to immediately shift the automatic transmission 2 is output to the automatic transmission 2 when the deceleration shift determination means 11 determines that the shift is not to be shifted. Transmission control means 12.

 Hereinafter, specific examples will be described.

Embodiment 1 In the case of the present embodiment, the deceleration shift determining means 11 has a function of comparing the engine torque Te and the running resistance torque Tc to determine whether or not the shift is a deceleration shift. That is, the running resistance torque Tc is calculated from the engine torque Te.
Is large (ie, Te <Tc), it is determined that the shift is to shift to the deceleration state (ie, the reverse drive state). The engine torque Te is to be read from the map shown in FIG. 5 based on the value of the intake pipe negative pressure Tvo (or the intake air amount Av).
The running resistance torque Tc is calculated from the turbine torque Tt before shifting (estimated from the current vehicle speed or the speed ratio before shifting) and the vehicle speed change ΔV based on Tc = Tt−ΔV · C (1) It is supposed to be. Here, C is a constant.

Next, the operation of the shift control device for the automatic transmission according to the first embodiment will be described with reference to the flowchart shown in FIG.

Control in this embodiment is intended when the upshift determination is made, at step S _1, the intake pipe negative pressure Tvo, engine speed Ne, turbine speed Nt and the vehicle speed V are read from time to time. Then, it is negative rate of change dTVO / dt of the intake pipe negative pressure Tvo at step S ₂ (i.e., dTvo / dt <0) or not is determined. That is, it is determined whether or not a shift-up shift (in other words, a back-out shift) at the time of returning the accelerator is performed. Thus, if it is determined that the back-out speed after the fifth Fig map from the engine torque Te shown is read based on the intake pipe negative pressure Tvo at step S _3, the running resistance torque Tc in step S ₄ Is calculated based on the above equation (1). That is, Tc = Nt−Δ
The running resistance torque Tc is obtained from VC.
Thereafter, comparison between the engine torque Te and the running resistance torque Tc in step S ₅ is made, since when it is determined that Te <Tc is decelerating state (i.e., reverse driving state) is a lever to shift to the engine rotational when the number Ne and the turbine speed Nt is equal (i.e., the point in the third stamen B), the shift instruction signal Rs (t) is output to the automatic transmission 2 (step S ₆ and S ₇ ). On the other hand, in step S _5,
If it is determined that Te ≧ Tc is decelerating state (i.e., reverse driving state) for non-transmission to shift to the shift instruction signal Rs control for automatic transmission 2 proceeds to step S ₇ immediately
(T) is output. Note that when the accelerator is depressed before the engine speed Ne and turbine speed Nt is synchronized, the change rate of the intake pipe negative pressure Tvo at step S ₈ d
This is detected when Tvo / dt becomes positive, and the control ends. Also, if it is determined that dTvo / dt ≧ 0 in step S ₂ (i.e., if it is determined not to be backed out shift), the immediately shift instruction signal Rs to the automatic transmission 2
(T) is output.

As described above, according to the present embodiment, the engine torque Te
Is compared with the running resistance torque Tc to determine whether or not the shift is to shift to the deceleration state by the deceleration shift determination means 11. If the determination is Te <Tc, the automatic transmission 2 By delaying the output of the shift instruction signal Rs (t) until the engine speed Ne and the turbine speed Nt are synchronized, it is possible to reduce shift shock at the time of deceleration transition, and when the determination is Te ≧ Tc Thus, by immediately outputting the shift instruction signal Rs (t) to the automatic transmission 2, unnecessary shift delays can be prevented.

Embodiment 2 In the case of the present embodiment, the engine torque Te and the running resistance torque Tc at the time of steady running are replaced by the intake pipe negative pressure Tvo, and as shown in FIG. as a guideline Tvo line X, the Tvo and the upper and lower regions of the line X and the map is divided into a transmission region Y ₂ to shift to the shift zone Y ₁ and deceleration condition is not shifted to the deceleration state is prepared, the deceleration shift determination means Reference numeral 11 has a function of reading from the map whether the negative pressure Tvo in the intake pipe belongs to the above-mentioned region Y ₁ or Y ₂ to determine whether or not the shift is to shift to deceleration. That is, the negative pressure Tvo in the intake pipe is equal to Tvo
If it belongs to the lower region Y ₂ of the line X, the deceleration state (i.e.,
That is, it is determined that the shift is to shift to the (reverse drive state).

Next, the operation of the shift control device for an automatic transmission according to the second embodiment will be described with reference to the flowchart shown in FIG.

Control in this embodiment also, are those when the upshift determination is made, at step S _1, the intake pipe negative pressure Tvo, engine speed Ne, turbine speed Nt and the vehicle speed V are read from time to time. Then, it is negative rate of change dTVO / dt of the intake pipe negative pressure Tvo at step S ₂ (i.e., dTvo / dt <0) or not is determined. That is, it is determined whether or not a shift-up shift (in other words, a back-out shift) at the time of returning the accelerator is performed. Thus, if it is determined that the back-out shifting, the intake pipe negative pressure Tvo at step S ₃ is, it is determined whether they belong to any region Y _1, Y ₂ in the map of Figure 7 shown made, area If it is determined to belong to Y ₂ is decelerated state (i.e., reverse driving state) for a transmission to shift to the engine speed Ne and turbine speed Nt
Are equal (ie, point B in FIG. 3A)
In the shift instruction signal Rs (t) is output to the automatic transmission 2 (Step S ₄ and S _5). On the other hand, in step S _3, if it is determined to belong to the region Y ₁ is decelerating state (i.e., reverse driving state) not shift to migrate to,
Control shift instruction signal Rs to the automatic transmission 2 (t) is outputted proceeds to step S ₅ immediately. Note that when the accelerator is depressed before the engine speed Ne and turbine speed Nt is synchronized, detects this by a change rate dTVO / dt is positive in the intake pipe negative pressure Tvo at step S ₆ And
Control ends. Further, dTvo / dt ≧ In step S ₂
When it is determined to be 0 (that is, when it is determined that the shift is not a backout shift), the shift instruction signal Rs (t) is output to the automatic transmission 2 immediately.

As described above, according to this embodiment, the intake pipe negative pressure Tvo
There by belongs to which region Y _1, Y ₂ in the map of FIG. 7 shown, it is determined whether or not shift to shift to the deceleration state by the reduction shift determining means 11, the determination is "region Y ₂
”, The output of the shift instruction signal Rs (t) to the automatic transmission 2 is delayed until the engine speed Ne and the turbine speed Nt are synchronized, thereby reducing shift shock at the time of shifting to deceleration. When the determination is “belongs to the region Y ₁ ”, the transmission of the shift instruction signal Rs (t) to the automatic transmission 2 immediately causes unnecessary shift delay. It can be prevented.

Further, in the above embodiment, the Tvo line X is fixed, but in the case of a vehicle equipped with a gradient sensor, as shown by a virtual line in FIG.
The line X 'or the downhill Tvo line X "may be changed.

[Brief description of the drawings]

FIG. 1 is a functional diagram of a shift control device for an automatic transmission according to the present invention, FIG. 2 is a schematic configuration diagram showing a shift control device for an automatic transmission according to the present invention, and FIGS. "With synchronization"
FIG. 4 is a characteristic diagram showing changes over time in the engine speed and the turbine speed in the case of “No synchronization”
FIG. 5 is a flowchart for explaining the operation of the shift control device for the automatic transmission according to the first embodiment of the present invention. FIG. 5 is a map for reading the engine torque based on the negative pressure in the intake pipe, and FIG. FIG. 7 is a flowchart for explaining the operation of the shift control device for an automatic transmission according to the second embodiment of the present invention. FIG. 7 is a map for reading "with synchronization" and "without synchronization" from the relationship between vehicle speed and negative pressure in the intake pipe. It is. DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Automatic transmission 3 ... Intake pipe 11 ... Deceleration shift determination means 12 ... Shift control means

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Claims (1)

(57) [Claims] 1. An automatic transmission having a torque converter and a gear transmission mechanism, an engine load detecting means for detecting an engine load, a vehicle speed detecting means for detecting a vehicle speed, and an engine load detected by the engine load detecting means. When the engine load detected by the engine load detecting means is smaller than a predetermined engine load defined based on the vehicle speed detected by the vehicle speed detecting means when the shift-up shift occurs due to a decrease in A deceleration transition determination unit that determines that the shift is a shift to a state; and a command to delay the shift for a predetermined time to the automatic transmission when the deceleration transition determination unit determines that the shift is to be performed. Output, and when it is determined by the deceleration shift determination means that the shift is not in deceleration shift, Serial shift control device for an automatic transmission, characterized in that immediately and a shift control means for outputting a command to be shifting to the automatic transmission.