JPH03199751A - Speed change method of automatic transmission - Google Patents

Abstract

PURPOSE:To eliminate deceleration in the case of starting after a quick stop by comparing a deceleration car speed V0 to a minimum speed shift, based on a shift position signal, with a car speed V1 and performing a speed change to the minimum speed shift at the time of a relation where V1<V0. CONSTITUTION:When a D signal from a shift lever 63 is input to the first control circuit 61 of a speed changer controller 60, an automatic speed change of a speed changer 16 is performed between shifts of forward 7-speed F7 to forward 2-speed F2, and when a quick stop is performed by quick braking in a condition of running in the shift of forward 7-speed F7, a speed change is performed to the shift of forward 2-speed F2, in the case of no abnormality in an output shaft speed sensor 49, with a car speed V1 decreased to a deceleration car speed V0 or less to the shift of forward 2-speed F2. Thus, a speed change with no feeling of physical disorder is attained without deceleration from the shifts of forward 3-speed F3 and forward 4-speed F4 even when the car speed V1 is V0 or less by a delay of rise up in a speed of an engine 10 at the time of restarting after a quick stop.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gear shifting method for an automatic transmission that automatically shifts gears based on the traction force and vehicle speed of each speed stage.

[Conventional technology]

As an automatic transmission, the points at which speed increases or decreases depending on the relationship between the traction force of each speed stage and the vehicle speed, that is, the shift points, are set based on the vehicle speed, and the vehicle speed is detected based on the engine output rotation speed, etc. There are known devices that automatically shift to the next speed stage when the shift point is exceeded.

For example, as shown in FIG. 5, forward 1st speed F1 to forward 7th speed F
Shift points f and -f6 are set based on the relationship between the traction force and the vehicle speed in No. 7, and when the vehicle speed exceeds the shift point, the gear is automatically shifted to the next speed gear.

[Problem to be solved by the invention]

In such a gear shifting method, the gear is shifted to the next gear after a predetermined period of time has elapsed since the vehicle speed reaches the gear shifting point, thereby avoiding repeating frequent gear shifting.

In other words, a time period during which shifting is not possible is provided for each speed stage.

For this reason, when the vehicle suddenly stops due to sudden braking while driving at a high speed, the automatic transmission will be delayed in decelerating and downshifting, causing deceleration to occur even after the vehicle has stopped. When trying to restart after a stop, the automatic transmission does not change to the lowest speed gear but instead to the middle speed gear, resulting in an odd shift where the vehicle decelerates once and then speeds up and shifts up again when restarting. There are things to do.

For example, if you are driving in 7th forward speed F7 and suddenly brake and suddenly stop, 7th forward speed F7 - 6th forward speed F6 - 5th forward speed F5 - 4th forward speed F4... 1st forward speed F1 and 1st gear Since the vehicle speed is sequentially decelerated after the non-shifting time has elapsed, when the accelerator pedal is depressed to restart after a sudden stop, the vehicle is in 4th forward gear, and due to the delay in increasing the engine speed due to the accelerator pedal depression, the vehicle speed is in 3rd forward gear. The speed change point becomes 4th forward speed and the speed is increased to 4th forward speed as the engine speed increases.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a method of changing speeds for an automatic transmission that can solve the above-mentioned problems.

[Means and effects for solving the problem] When the vehicle speed is lower than the deceleration speed to the lowest speed gear based on the shift position signal, the gear is shifted to the lowest speed gear, thereby reducing the speed of re-starting after a sudden stop due to sudden braking. This is a speed change method in which the speed is increased as the engine speed increases without being decelerated when starting.

〔Example〕

As shown in FIG. 3, an output shaft 11 of an engine 10 is connected to a pump 14 of a torque converter 13 via a drive shaft 12, and a turbine 15 is connected to an input shaft 1 of a transmission 16.
A lock-up clutch 18 is provided to connect the pump 14 and the turbine 15, and the transmission 16 connects the human power shaft 17 to the output shaft 20 via a plurality of planetary gear mechanisms 19. Clutch 21, low speed clutch 22, first to fourth clutches 23 to 26, reverse clutch 2
By turning ON and OFF 7, the speed can be changed from 1st forward speed to 7th forward speed and reverse, and its output shaft 20 is connected to the drive wheels 5 via a differential 28 and two final reduction gears. .

As shown in FIG. 4, each of the clutches is controlled intermittently by controlling the supply of pressure oil discharged from the pump 30 by the first to seventh shift valves 31 to 37, and the first to seventh shift valves 31 to 3
7 is designed to be switched to the supply position by energizing the solenoids 31a to 37a, and to be in the cutoff position when not energized, and is connected to the input side of the first and second speed change pulps 31 and 32 and the third to seventh speed change positions. A modulation valve 38 is provided on the input side of each of the valves 33 to 37 so that the hydraulic pressure supplied to each clutch increases smoothly.
0 discharge pressure oil is supplied through the lock-up switching valve 40, and when the solenoid 40a is energized, it is in the supply position, the lock-up clutch 18 is turned on, connecting the pump 14 and the turbine 15, and when it is demagnetized, it is in the cut-off position. This is so that the lock-up clutch 18 is turned off.

In FIG. 1, the engine 10 includes an electronically controlled governor 42.
A fuel injection pump 42a whose fuel injection amount is controlled is provided, and its electronically controlled governor 42 controls the fuel injection amount by reciprocating a rack rod 43 with a cylinder 44. The chamber 44a is supplied with discharge pressure oil from a hydraulic source (not shown) through a control valve 45, and is provided with a rack position detection sensor 46 consisting of a differential transformer, which detects the rotational speed of the output shaft 11 of the engine 10. In addition, the transmission 16 is provided with an engine rotation sensor 47 that detects an input shaft 17 and an output shaft 2.
An input shaft speed sensor 48 and an output shaft speed sensor 49 are provided to detect a rotation speed of 0.

50 is an engine controller, and an accelerator pedal 5
When an accelerator opening signal from an accelerator sensor 52 that detects the amount of depression (accelerator opening) of 1 is input, a control signal is output to the control valve 45 to supply discharge pressure oil from the hydraulic source to the chamber 44a of the cylinder 44. By controlling the rack lever 43, the rack rod 43 is reciprocated, and the rack position detected by the rack position detection sensor 46 is controlled to be a rack position corresponding to the accelerator opening signal.

A transmission controller 60 calculates the vehicle speed based on the input shaft speed sensor 48 or output shaft speed sensor 49 of the transmission 16, the human power shaft speed or output shaft speed from the engine rotation sensor 47, and the engine rotation speed. When the vehicle speed exceeds the set shift point, the first to seventh shift valves 31 to 3
A control signal is output to the lock-up switching valve 41 and the lock-up clutch 18 to disengage the torque converter 13.
After the engine 10 and the transmission 16 are connected via the engine 10 and the transmission 16, the speed is changed to a higher or lower speed than the current speed, and after the shifting is completed, the lock-up clutch 18 is connected to directly connect the engine 10 and the transmission 16. The first
A control circuit 61 and a second control circuit 62 are provided.

In addition, shift position signals R, N, DSV, IV, ■, ■ are inputted to the first control circuit 61 from the shift lever 63, and when the R signal is input manually, the gear is shifted to reverse, and when the N signal is input manually, the gear is shifted to reverse. Shift to neutral, D, V, I
V, ■, II (When G is manually operated, it automatically changes gears between predetermined speed stages.

The second control circuit 62 receives an accelerator opening signal from the accelerator sensor 52, a transmission output shaft rotational speed from the output shaft speed sensor 49, a current speed stage signal from the first control circuit 61, and a shift signal from the shift lever 63. The position signal is input manually, the vehicle speed V is calculated from the transmission output shaft rotational speed, and the vehicle speed is compared with the deceleration vehicle speed ■o to the lowest speed gear based on the shift position signal from the shift lever 63, and V,<
When V, it is determined whether there is an abnormality in the output shaft speed sensor 49, and if there is no abnormality, it outputs a speed command to the lowest speed gear based on the shift position signal, and when v,>V, the first control circuit 61 Normal gear shifting is carried out, and when v,>Vo and the output shaft speed sensor 49 is abnormal, a failure is displayed.

Here, abnormality determination of the output shaft speed sensor 49 is based on the human power shaft rotation from the human power shaft speed sensor 48 and the intermediate shaft speed sensor 64.
The determination is made based on whether the intermediate shaft rotation from the output shaft speed sensor 49 and the output shaft rotation from the output shaft speed sensor 49 are at a predetermined ratio, and whether there is a disconnection or short circuit in the circuit of the output shaft speed sensor 49.

The above-mentioned speed change operation is shown in a flowchart as shown in FIG.

Next, a specific example will be explained.

When the shift lever 63 is in the D position and the D signal is input to the first control circuit 61, the gears are automatically shifted between 7th forward speed F7 and 2nd forward speed F2, and sudden braking is performed while the vehicle is running at 7th forward speed F7. When the vehicle suddenly stops, the vehicle speed V becomes less than the deceleration vehicle speed V0 to the forward 2nd speed F2, and if there is no abnormality in the 4 output shaft speed sensors, a command for the forward 2nd speed F2 is output and the gear is shifted to the forward 2nd speed F2. do.

As a result, even when the vehicle speed V is lower than v0 due to a delay in the rise of the engine speed when restarting after a sudden stop, the speed is not decelerated from the third forward speed F3 or the fourth forward speed F4, resulting in a shift that does not give a sense of discomfort.

〔Effect of the invention〕

When you brake suddenly and come to a sudden stop, the gear changes to the lowest speed gear when it reaches V or >Vo, so there is no deceleration when restarting after a sudden stop, and the speed gradually increases based on the increase in vehicle speed due to the increase in engine speed. Since the gears are shifted faster, you can shift without feeling any discomfort.

[Brief explanation of drawings]

Fig. 1 is an overall explanatory diagram of the apparatus for carrying out the method according to the present invention, Fig. 2 is an operation flowchart, Fig. 3 is an explanatory diagram of the power transmission mechanism, Fig. 4 is a shift hydraulic circuit diagram, and Fig. 5 is a shift diagram. It is an explanatory diagram showing an example of a pattern.

Claims (1)

[Claims] In an automatic transmission that automatically changes gears by changing vehicle speed between predetermined speed stages based on a shift position signal from the shift lever 63, vehicle speed V_0 decelerated to the lowest speed stage based on the shift position signal is compared with vehicle speed V_1 to determine that V_1< A method of shifting an automatic transmission, characterized in that when V_0, the gear is shifted to the lowest speed gear.