FASTENING PRESSURE CONTROL DEVICE FOR STARTING FRICTION ELEMENT AT TIME OF CONTROLLING IDLE STOP OF VEHICLE

• US 20110071740A1
• Filed: 05/21/2009
• Published: 03/24/2011
• Est. Priority Date: 06/04/2008
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Matsuda, Takashi, Koga, Masato, Nihei, Hironori
• Granted Patent: US 8,386,138 B2
• Time in Patent Office: Days
• US Class Current: 701/54
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: F16D 2500/3067 Speed of the engine
• CPC Class Codes: F16D 2500/5045 Control of engine at idle, i.e. controlling engine idle conditions, e.g. idling speed
• CPC Class Codes: F16D 2500/70406 Pressure
• CPC Class Codes: F16D 48/066 Control of fluid pressure, e.g. using an accumulator F16D48/062, F16D48/068 take precedence
• CPC Class Codes: F16H 2061/66286 Control for optimising pump efficiency
• CPC Class Codes: F16H 57/0439 using multiple pumps with different power sources or a single pump with different power sources, e.g. one and the same pump may selectively be driven by either the engine or an electric motor
• CPC Class Codes: F16H 61/0031 using auxiliary pumps, e.g. pump driven by a different power source than the engine
• CPC Class Codes: F16H 61/66272 characterised by means for controlling the torque transmitting capability of the gearing

Abstract

A required draining capacity of an electrically-powered oil pump is reduced and a small sizing of the electrically-powered oil pump is achieved by devising how to issue a starting frictional element engagement pressure command value.

[Means for Solving the Problem]

An engine is restarted in response to an idle stop OFF command at t1 so that a gear shift control purpose hydraulic pressure is raised according to a working oil from an engine driven oil pump. An idle stop release time control of the engine is allowed according to a torque down unnecessary determination when a gear shift control purpose hydraulic pressure has reached to a set hydraulic pressure at t2. In a case where this allowance causes an engine torque Te to be raised from a torque down value toward a driving operation corresponding value by a predetermined gradient ΔTe1, a command value of a starting frictional element engagement pressure P_S is set to a control maximum value (a drain port opening angle of a clutch hydraulic pressure control valve for a clutch hydraulic pressure (an engagement pressure) command value is made small as compared with that in a case of an ordinary control (is made difficult to drain)) during the idle stop control including during the idle stop release time control. Thus, when starting frictional element engagement pressure P_S is controlled upon receipt of this command value, the working oil from the electrically-powered oil pump is not needed to be drained. Consequently, the electrically-powered oil pump is not needed to discharge this draining working oil and the small-sizing can be achieved.

Claims

1. An engagement pressure control apparatus for a starting frictional element at a time of an idle stop control of a vehicle, comprising:

an engine;

drive wheels;

a transmission configured to transmit a power of the engine to the drive wheels via the starting frictional element under a gear shift;

a gear shift control section configured to perform a gear shift control for the transmission by means of a hydraulic pressure from an engine driven oil pump driven by the engine, during a driving of the engine; and

an idle stop control section configured to, when a predetermined condition is established, perform an idle stop such that the engine is automatically stopped and make the starting frictional element an engagement start immediate before state according to the engagement pressure produced by a partial draining of a working oil from an electrically-powered oil pump by means of a starting frictional element engagement pressure control section and to, when the predetermined condition becomes un-established, restart the engine in response to a release of the idle stop and make the engine a driving operation responding state, at a time of a vehicle stop determination, wherein, during an operation of the idle stop control section, a drain port opening angle of a clutch hydraulic pressure control valve for an engagement pressure command value issued to the starting frictional element engagement pressure control section is made small as compared with the drain port opening angle of an ordinary control in accordance with an input torque of the starting frictional element.

2. The engagement pressure control apparatus for the starting frictional element at the time of the idle stop control of the vehicle as set forth in claim 1, wherein the electrically-powered oil pump is configured to set the engagement pressure command value issued to the starting frictional element engagement pressure control section to a control maximum value.

3. The engagement pressure control apparatus for the starting frictional element at the time of the idle stop control of the vehicle as set forth in claim 2, wherein the electrically-powered oil pump has a pump capacity enough to drain the working oil by a quantity such that the starting frictional element is made in an engagement start immediate before state when the engagement pressure command value issued to the starting frictional element engagement pressure control section is set to the control maximum value.

4. The engagement pressure control apparatus for the starting frictional element at the time of the idle stop control of the vehicle as set forth in claim 2, wherein, during a failure under which it is impossible for the electrically-powered oil pump to generate a regular hydraulic pressure, the engagement pressure command value issued to the starting frictional element engagement pressure control section is an intermediate shelf pressure equivalent value in place of the control maximum value.

5. The engagement pressure control apparatus for the starting frictional element at the time of the idle stop control of the vehicle as set forth in claim 1, wherein, when an output control system of the engine has failed, the engagement pressure command value issued to the starting frictional element engagement pressure control section is set to an intermediate shelf pressure equivalent value in place of a control maximum value.

6. The engagement pressure control apparatus for the starting frictional element at the time of the idle stop control of the vehicle as set forth in claim 1, wherein, when a selection range of the transmission is switched during a time duration from a time at which the engine is restarted in response to the release of the idle stop to a time at which an idle stop release time control is started, the command value of the engagement pressure issued to the starting frictional element engagement pressure control section is set to an intermediate shelf pressure equivalent value in place of the control maximum value.

7. The engagement pressure control apparatus for the starting frictional element at the time of the idle stop control of the vehicle as set forth in claim 4, wherein the intermediate shelf pressure equivalent value is a return spring equivalent pressure required for the starting frictional element to be in the engagement start immediate before state against a built-in return spring.