CONTROL DEVICE AND CONTROL METHOD FOR AUTOMATIC TRANSMISSION

Abstract

When an N position sensor is ON, even though the N position is selected, the oil pressure supplied to a clutch C1 which is engaged during the transition from the non-running state to the running state is raised in advance to a predetermined oil pressure; and, if a running request is detected when a D position decision has not been made, irrespective of whether or not a shift lever has been shifted from its N position to its D position, first speed starting off from rest control is performed, in which the oil pressure supplied to the clutch C1 is raised to an oil pressure at which the clutch C1 is capable of power transmission.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and further objects, features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein:

FIG. 1 is a general structural figure showing a power train controlled by an ECU which is a control device according to an embodiment of the present invention;

FIG. 2 is a skeleton diagram showing the gear train of this automatic transmission;

FIG. 3 is a figure showing an operating table of this automatic transmission;

FIG. 4 is a figure showing essential portions of an oil pressure circuit of this automatic transmission;

FIG. 5 is a flow chart showing the structure of a control program executed by this ECU which is a control device according to an embodiment of the present invention;

FIG. 6 is a timing chart during garage shifting according to the method of the present invention; and

FIG. 7 is a timing chart during garage shifting according to a related art method.

Claims

1. A control device for an automatic transmission which transits from a non-running state to a running state by a friction engaging element which is operated by oil pressure transiting from a state in which it is released to a state in which it is engaged, comprising: a shift position detection unit which detects shift positions, including a first shift position which corresponds to the non-running state and a second shift position which corresponds to the running state, based upon the position of a shift actuation mechanism; andan oil pressure control unit which raises the oil pressure supplied to the friction engaging element, when the shift position detection unit detected that the shift position is the first shift position.

2. A control device for an automatic transmission according to claim 1, further comprising: a running request detection unit which detects a running request if, irrespective of whether or not the position of the shift actuation mechanism is a position which corresponds to the second shift position, the shift position detection unit cannot detect that the position of the shift actuation mechanism is the second shift position; anda starting control unit which, if a running request is detected, raises the oil pressure supplied to the friction engaging element, until the friction engaging element is brought to a power transmission state.

3. A control device for an automatic transmission according to claim 1, further comprising: a running request detection unit which detects a running request if, irrespective of whether or not the position of the shift actuation mechanism is a position which corresponds to the second shift position, the shift position detection unit detects that the position of the shift actuation mechanism is the first shift position; anda starting control unit which, if a running request is detected, raises the oil pressure supplied to the friction engaging element, until the friction engaging element is brought to a power transmission state.

4. A control device for an automatic transmission according to claim 2, further comprising: an output shaft rotational speed detection unit which detects the output shaft rotational speed of the automatic transmission; andan oil pressure control unit which raises the oil pressure supplied to the friction engaging element to maximum, if the running request is detected, and if based upon the output shaft rotational speed it is decided that the vehicle is running.

5. A control device for an automatic transmission according to claim 4, further comprising a working oil temperature detection unit which detects the temperature of the working oil of the automatic transmission; and wherein the oil pressure control unit raises the oil pressure supplied to the friction engaging element, if the temperature of the working oil is lower than a predetermined temperature.

6. A control method for an automatic transmission which transits from a non-running state to a running state by a friction engaging element which is operated by oil pressure transiting from a state in which it is released to a state in which it is engaged; comprising: detecting shift positions, including a first shift position which corresponds to the non-running state and a second shift position which corresponds to the running state, based upon the position of a shift actuation mechanism; andraising the oil pressure supplied to the friction engaging element, when the detected shift position is the first shift position.

7. A control method for an automatic transmission according to claim 6, further comprising: detecting a running request if, irrespective of whether or not the position of the shift actuation mechanism is a position which corresponds to the second shift position, it is not possible to detect that the position of the shift actuation mechanism is the second shift position; andif a running request is detected, raising the oil pressure supplied to the friction engaging element, until the friction engaging element is brought to a power transmission state.

8. A control method for an automatic transmission according to claim 6, further comprising: detecting a running request if, irrespective of whether or not the position of the shift actuation mechanism is a position which corresponds to the second shift position, it is detected that the position of the shift actuation mechanism is the first shift position; andif a running request is detected, raising the oil pressure supplied to the friction engaging element, until the friction engaging element is brought to a power transmission state.

9. A control method for an automatic transmission according to claim 7 or claim 8, further comprising: detecting the output shaft rotational speed of the automatic transmission; andraising the oil pressure supplied to the friction engaging element to maximum, if the running request is detected, and if based upon the output shaft rotational speed it is decided that the vehicle is running.

10. A control method for an automatic transmission according to claim 9, further comprising: detecting the temperature of the working oil of the automatic transmission; andraising the oil pressure supplied to the friction engaging element, if the temperature of the working oil which is detected is lower than a predetermined temperature.