JPH01269747A - Speed change control device of automatic transmission - Google Patents

Abstract

PURPOSE:To provide regularly a moderate action of engine brake by determining the width of downshift by the used gear stage and the car speed range at that time. CONSTITUTION:A downshift determining means F inputs car speed information from a car speed detecting means A, deceleration information of a deceleration detecting means C, and gear position information from a gear position determining means J. When the present used gear stage is 4th speed and the deceleration is a determined value or more, the gear is shifted down to 2nd speed if the car speed is within a specified range, and to 3rd speed if within a determined range more than this. On the other hand, when the present used gear stage is 3rd speed and the deceleration is another determined value or more, the gear is shifted down to 2nd speed if the car speed is within another determined range. Thus, as the down width of downshift is changed according to the speed range of the vehicle, a moderate action of engine brake can be provided regularly in both low speed and high speed ranges.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a shift control device for an automatic transmission, and particularly relates to shift control during braking of a vehicle.

(Prior Art) As a conventional shift control device for an automatic transmission, for example, the "Nirasan Automatic Transmission L" published by Nissan Motor Co., Ltd. in November 1982 is an example.
4 N71B type, E4N71B type maintenance manual (A26
1 C04) There are some listed in J.

(Problem to be Solved by the Invention) However, in such a conventional automatic transmission shift control device, the idle switch, vehicle speed and brake switch are detected, and the vehicle speed is within a preset range, and the idle switch is detected. If the switch is ON and the brake switch is ON, the engine brake is activated by shifting down one gear from normal, so no matter the vehicle speed, the engine braking force is only available from the gear one gear lower. I couldn't get it. For this reason, at high vehicle speeds, the driver can feel that the engine brake is working, but at low vehicle speeds, it sometimes feels like the engine brake is not working effectively.

(Means for Solving the Problems) This invention improves such conventional techniques,
In an automatic transmission that operates engine braking by downshifting to a low gear depending on conditions during braking, the width of the downshift is determined by the gear used at that time and the vehicle speed range.

(Function) As described above, this invention is configured to change the downshift (for example, 4→2, 4→3 downshift) depending on the speed range of the vehicle, so even in a low vehicle speed range. , it is possible to apply appropriate engine braking even at high vehicle speeds.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.

First, to explain the configuration, the vehicle speed detection means A calculates the vehicle speed by counting pulse signals from a vehicle speed sensor provided on the output shaft of the automatic transmission H for a predetermined period of time (for example, 100 m5 or 354 m5). The braking operation detection means B detects a brake signal from a brake switch to determine whether or not a braking operation is performed. The deceleration detection means C determines the deceleration from the change in the signal from the means A at a predetermined period, and can also be determined from the longitudinal G sensor of the vehicle.

The idle state detection means detects a signal from a throttle fully closed switch (idle switch) provided in a throttle chamber of the engine to determine whether or not the engine is in an idle state. Other information E is information necessary for conventional speed change control (throttle opening, temperature of hydraulic fluid in the automatic transmission, etc.).

Further, the downshift determining means F for engine braking is
Input vehicle speed information from means A, brake information from means B, deceleration information from means C, idle information with off-delay from means ■, gear position information from means J, and manual engine brake signal from means K. Then, it is determined whether or not the downshift condition for engine braking is satisfied, and the result is sent to the speed change control means G.

The gear change control means G basically controls the gear position determined by the means J, and when downshifting for engine braking,
Shift control is performed to the gear position of means F.

Furthermore, in response to a downshift request from the downshift determining means F for engine braking, shift control, control of the clutch for engine braking, and prohibition of upshifting are performed. Further, the off-delay setting means (2) sets a delay only when the idle is off for the idle information from the means (2).

The gear position determining means J based on the shift pattern determines the current gear position in accordance with the shift pattern selected by the driver, in a conventional manner.

The manual engine brake selection means is configured to switch to an engine brake pattern in response to an input signal from the driver (overdrive prohibition switch, select lever 11211."1" range signal).

The explanation of this example is based on Nissan Motor Co., Ltd.
REdROIA type (maintenance manual A2) issued in March 2017
This is an example in which the present invention is applied to the automatic transmission of 61CO7), and its specific configuration requires only adding a brake switch input circuit to the control circuit of the REdROIA type automatic transmission.

Next, the action will be explained.

Here, the speed change control means G including the deceleration detection means C, the downshift determination means F for engine braking, and the off-delay setting means I will be explained. Other parts are similar to the conventional example.

First, the deceleration detection means C will be explained (see FIG. 2).

The counter C is incremented by 1 each time a pulse from the vehicle speed sensor is input. Also, a predetermined period (for example, 100
m5, or 354 m5, etc.), Δ proportional to the deceleration is calculated from the previous counter value C' and the current counter value C.
At the same time as computing C, C' is updated and the counter C is cleared. Thereby, the deceleration ΔC is detected at every predetermined period. Note that here we are looking for deceleration rather than vehicle speed,
Naturally, it is also possible to determine the deceleration from the output of a longitudinal G sensor or the like.

Next, the downshift determining means F for engine braking will be explained with reference to FIG.

Here, when OD (overdrive) is prohibited, automatic engine brake control is prohibited in third gear, and automatic engine brake control is prohibited in ranges other than "D'".

In addition, downshift request flags FDS2 (downshift to 2nd gear) and FDS3 (3
(downshift to speed) also serves as a request to prohibit upshifts. (FDS 2 ” - Prohibits upshifting to 3rd gear or higher, FDS 3 - Prohibits upshifting to 4th gear) ■First, check whether it is in the “D”° range or not. “D゛.

When it is outside the range (that is, the "2-pass,""1" range), it ends as FDS 2 = 01FDS 3.0.

■Next, check the status of IDLH, and
If not, go to ■.

■Next, check the FIDL flag and
When 〇 (that is, idle off → on), FDS
2=O, FDS3=O (downshift reset for engine brake), FIDL/engineering.

■Check whether OD is prohibited, and if OD is prohibited,
Set FDS 3 = O and release the 3rd speed engine brake by automatic control.

0 Next, the brake is checked, and if the brake is off, the process ends.

0th order, FDS 2. Check FDS 3, if either is 1 (engine brake is already activated)
Exit.

0~0 Next, check the vehicle speed (VSP) and deceleration (ΔC) depending on the currently used gear (4th or 3rd gear).
), and if the conditions are satisfied, the FD
S2. Set FDS3 to 1. When in 4th gear, downshifts of 4→2 and 4→3 are used depending on the vehicle speed range. (Part of the present invention) [Phase] In the case of idle off, first check FIDL, and when FIDL・1 (
In other words, for idle on-off), the delay time is set in the timer T, and FIDL=O.

0 Next, at T 0 (that is, after the delay time from idle on-off), FDS 2 = O, FDS 3
20 and cancel the downshift for engine braking.

Note that the timer T is decremented every predetermined time (for example, 10 m5) as shown in FIG.

Next, the gear position determining means J based on the shift pattern and the shift control means G will be explained with reference to FIGS. 5 and 6.

■First, as usual, the operating conditions (throttle opening TVθ,
(vehicle speed vsp, etc.).

■Next, the gear position GP is determined based on the shift pattern.

■、■Next, engine brake request flag FDS2,
Check FDS 3, and if FDS 3 = O, when the gear stage GP is 3rd or higher, the GP is changed to 3rd gear, and when it is 2nd or lower, the GP remains unchanged and FDS 3 is changed.
= O. With FDS 2.1, when GP is 2nd gear or higher, GP is changed as 2nd gear, and when it is 1st gear, GP is changed.
Leave as is and set it as FDS 2.0. As shown in FIG. 6, the engine brake clutch is basically an FDS 2. It is engaged when either FDS 3 is 1, and released when both are 0 (when a downshift for engine braking is released).

(Effects of the Invention) As described above, in the present invention, the downshift width (for example, 4→2, 4→3 downshift) is changed depending on the speed range of the vehicle. However, the effect is that even at high vehicle speeds, the engine brake can always be applied appropriately.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the configuration of the present invention, Figures 2 to 6
The figure is a flowchart for explaining the operation of the present invention. A...Vehicle speed detection means B...Braking operation detection means C...Deceleration detection means D
... Idle state detection means E ... Other information F ... Downshift determination means G for engine braking
...Shift control means H...Automatic transmission I...
・Off-delay setting means J...Gear determining means K based on shift pattern...Manual engine brake selection means Fig. 2

Claims (1)

[Claims] 1. An automatic transmission that operates engine braking by downshifting to a lower gear depending on conditions during braking, characterized in that the width of the downshift is determined by the gear used at that time and the vehicle speed range. Shift control device for automatic transmission.