JPH0587224A - Shift control method of mechanical automatic transmission - Google Patents

Abstract

PURPOSE:To solve both problems of a step-up in gear-off resistance and an increase in shift time by holding the extent of engine speed larger than that of clutch disk rotational speed till a gear-off motion is finished by an up-shift at the time of low oil temperature and, after the gear-off operation is over, lowering the engine speed so as to accord it with the output rotational frequency of a transmission by degrees. CONSTITUTION:Engine speed NE is held to be larger than clutch disk rotational speed NC till a gear-off motion is finished by an up-shift at time of a low temperature of oil in a wet clutch 1. After the gear-off operation is over, the engine speed is controlled by a driving system controller and/or an engine controller so as to be gradually lowered in order to accord with power speed of a transmission through a smaller one than the clutch disk rotational speed NC. With this constitution, the extent of gear-off operating force is reduced and a synchromesh becomes smooth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control method for a mechanical automatic transmission having a wet clutch.

[0002]

2. Description of the Related Art In automobile clutches and transmissions,
A mechanical automatic transmission 2 (T / M), which is operated by a wet clutch 1 (C / L) and a shift / select cylinder (not shown), is known. NE is the engine speed, NC is the clutch disk speed, and NP is the output speed of the transmission 2.

[0003]

In the shift operation of the mechanical automatic transmission 2, the wet clutch 1 is disengaged from the connected state as shown by the line C / L in FIG. The gear is shifted up from the third speed to the third speed, and the wet clutch 1 is connected again. However, at low temperature, the oil temperature of the wet clutch 1 is naturally low and the viscosity is high, so that the drag torque of the wet clutch 1 increases and the mechanical automatic transmission 2
There is a problem that the gear removal resistance increases and the shift time becomes long.

In this type of mechanical automatic transmission, gear shifting resistance is improved by reducing the gear pull-out resistance and smoothly obtaining synchronization.

An object of the present invention is to provide a gear shift control device for a mechanical automatic transmission which solves the above-mentioned conventional problems and improves gear shifting performance.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, a featured configuration of the present invention is a mechanical automatic machine equipped with a wet clutch controlled based on a command signal of a controller and a shift / select cylinder. In the transmission,
When the oil temperature of the wet clutch is low, the engine speed is kept higher than the clutch disc speed until the end of the gear removal operation by the shift up, and after the gear removal, the engine speed is lower than the clutch disc speed. It gradually lowers so as to match the output speed of the transmission.

[0007]

With the above construction, when the wet clutch is disengaged by upshifting, the clutch drag torque acts in the direction of increasing the rotation of the clutch disc, and the gear disengaging operation force is reduced. Further, by synchronizing the engine speed, which has been increased, with the engine speed lower than the clutch disk speed, and by lowering the engine speed as soon as possible, a large clutch drag torque facilitates synchronization.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a wet clutch, 2 is a mechanical automatic transmission equipped with shift and select cylinders (hereinafter simply referred to as "transmission"), 3 is an engine, 4 is an oil temperature sensor of the wet clutch 1, and 5 is a fuel injection pump. , 6 is a drive system controller, and 7 is an engine controller.

According to the present invention, when the oil temperature of the wet type clutch 1 is low (for example, 50 ° or less), the engine speed NE is kept higher than the clutch disk speed NC until the end of the gear removing operation by the shift up, and the gear After disengagement, the engine speed NE is changed to the clutch disk speed N
The drive system controller 6 and the engine controller 7 control the drive system controller 6 and the engine controller 7 so as to gradually lower the rotational speed smaller than C to match the output rotational speed NP of the transmission.

More specifically, the C / L shown in FIG.
As shown by the line, the shift stroke line and the engine speed line, when the wet clutch 1 is disengaged and the gear is shifted up from the second speed to the third speed, the engine speed NE is set to the clutch disc speed in the gear disengagement operation range A. Hold larger than NC. As a result, the drag torque of the clutch disc becomes small in the gear removal operation range A as indicated by the dotted line D, and the gear removal can be smoothly obtained.

After the gear is disengaged, the engine speed NE is gradually lowered so as to match the output speed NP of the transmission at a speed smaller than the clutch disk speed NC, so that the speed of the transmission 2 is reduced as indicated by the shift range B. As shown by the solid line E, the drag torque drops in proportion to the clutch disc rotational speed, and the clutch disc drag torque increases in proportion to the difference between the clutch disc rotational speed NC and the engine rotational speed NE, which is advantageous for synchronization. Becomes Therefore, it is desirable to reduce the engine speed NE in the shift range B as soon as possible.

As a result of the above, it is possible to obtain good synchronism without increasing the gear disengaging operation force and to improve the shifting performance.

[0013]

As described above, the present invention provides a wet clutch,
In a mechanical automatic transmission, when the oil temperature of the wet clutch is low, the engine speed is kept higher than the clutch disc speed until the end of the gear disengaging operation when the gear is disengaged. Since the control is performed so that the output rotation speed of the transmission is gradually lowered at a rotation speed lower than the rotation speed, the gear removal resistance of the transmission can be reduced and the shift time can be shortened. It has the beneficial effect of eliminating all at once.

[Brief description of drawings]

FIG. 1 is a shift control circuit diagram of a mechanical automatic transmission showing an embodiment of the method of the present invention.

FIG. 2 is a control graph of the method of the present invention.

FIG. 3 is a sectional view showing a main part of a mechanical automatic transmission.

[Explanation of Codes] 1 Wet clutch 2 Mechanical automatic transmission 3 Engine 4 Oil temperature sensor 5 Fuel injection pump 6 Drive system controller 7 Engine controller NE Engine speed NC clutch disc speed NP Output speed of transmission

Claims (1)

[Claims] 1. A mechanical automatic transmission having a wet clutch controlled based on a command signal from a controller and a shift / select cylinder, wherein a gear-disengaging operation is performed by upshifting when the oil temperature of the wet clutch is low. The engine rotational speed is kept higher than the clutch disk rotational speed until the end, and after the gear disengagement, the engine rotational speed is gradually lowered to match the output rotational speed of the transmission at a rotational speed lower than the clutch disk rotational speed. Control method for a mechanical automatic transmission.