Clutch engagement for a transmission when in park

Patent metadata

Field	Value
Publication number	US-2017219028-A1
Application number	US-201615012230-A
Country	US
Kind code	A1
Filing date	Feb 1, 2016
Priority date	Feb 1, 2016
Publication date	Aug 3, 2017
Grant date	—

Abstract

A transmission includes a first hydraulic clutch, a second hydraulic clutch, a third hydraulic clutch, a pump and a controller. The first, second, and third hydraulic clutches are configured to established a parked-ready condition upon engagement of all three clutches. The pump is configured to generate hydraulic fluid pressure. The controller is programmed to, in response to a command to start an engine that powers the pump, engage the first and second clutches. The controller is further programmed to, in response to engagement of the first and second clutches and obtaining operating hydraulic fluid pressure, engage the third clutch.

First claim

What is claimed is:

1 . A transmission comprising:
first, second, and third hydraulic clutches configured to established a parked-ready condition upon engagement of all three clutches; a pump configured to generate hydraulic fluid pressure; and a controller programmed to,
in response to a command to start an engine that powers the pump, engage the first and second clutches, and
in response to engagement of the first and second clutches and obtaining operating hydraulic fluid pressure, engage the third clutch.

2 . The transmission of claim 1 , further comprising first, second, and third electrically operated hydraulic valves configured to direct hydraulic fluid into the first, second, and third clutches, respectively, to the engage the first, second, and third clutches.

3 . The transmission of claim 2 , wherein the controller is further programmed to regulate electrical power delivered to the first and second valves to engage the first and second clutches during a period after commanding the engine to start but prior to a first spark event of the engine to prevent depriving an engine starter motor of the required electrical power to start the engine.

4 . The transmission of claim 3 , wherein the electrical power delivered to the first and second valves to engage the first and second clutches, respectively, is adjusted during a second period after the first spark event of the engine such that the first and second valves are fully opened to allow maximum flow of hydraulic fluid into the first and second clutches to fully engage the first and second clutches.

5 . The transmission of claim 4 , wherein the third valve is operated to gradually increase the hydraulic pressure acting on the third clutch during engagement of the third clutch.

6 . The transmission of claim 5 , wherein a rate at which the third valve increases the hydraulic pressure acting on the third clutch is increased in response to a command to shift out of a parked condition.

7 . The transmission of claim 1 , wherein the third clutch engages after a predetermined period of time after the first and second clutches are engaged.

8 . The transmission of claim 1 , wherein the first and second clutches are engaged when opposing sides of the first clutch and opposing sides of the second clutch become synchronized after initiation of starting the engine.

9 . The transmission of claim 1 , wherein the first and second clutches are engaged when after a predetermined period of time after initiation of starting the engine.

10 . A method of establishing a parked-ready condition of a vehicle comprising:
engaging first and second transmission clutches in response to initiation of an engine start; generating a hydraulic pressure via a pump powered by the engine; and engaging a third transmission clutch after engaging the first and second clutches and after the hydraulic pressure exceeds a threshold, wherein engagement of the first, second, and third clutches establishes a parked-ready condition of the vehicle.

11 . The method of claim 10 , wherein first, second, and third electrically operated hydraulic valves are configured to direct hydraulic fluid into the first, second, and third clutches, respectively, to engage the first, second, and third hydraulic clutches.

12 . The method of claim 11 , further comprising the steps of:
delivering electrical power to the first and second valves to engage the first and second clutches, respectively; and regulating the electrical power delivered to the first and second valves during a period after initiation of starting the engine but prior to a first spark event of the engine to prevent depriving an engine starter motor of the required electrical power to start the engine.

13 . The method of claim 11 , wherein the third valve is operated to gradually increase the hydraulic pressure acting on the third clutch during engagement of the third clutch.

14 . The method of claim 13 , further comprising the step of increasing a rate at which the third valve increases the hydraulic pressure action on the third clutch in response to a shift out of the parked condition.

15 . The method of claim 10 , wherein the third clutch engages after a predetermined period of time after the first and second clutches are engaged.

16 . The method of claim 10 , wherein the first and second clutches are engaged when opposing sides of the first clutch and opposing sides of the second clutch become synchronized after initiation of starting the engine.

17 . The method of claim 10 , wherein the first and second clutches are engaged when after a predetermined period of time after initiation of starting the engine.

18 . A vehicle transmission controller comprising:
input channels configured to receive signals indicative of an engine starting, engagement of first and second transmission clutches, and a pressure of a transmission fluid; output channels configured to send commands to engage the first, the second, and a third transmission clutch; and control logic configured to command engagement of the first and second clutches upon initiation of the engine starting and to generate the command to activate the third clutch after engaging the first and second clutches and after obtaining a desired transmission fluid pressure such that engagement of the first, second, and third clutches establishes a parked-ready condition of the transmission.

19 . The controller of claim 18 , wherein the control logic is further configured to generate the command to activate the third clutch after a predetermined period of time after the first and second clutches are engaged.

20 . The controller of claim 18 , wherein the control logic is further configured to gradually engage the third clutch.

Assignees

• Ford Global Tech Llc

Inventors

• Mcdonnell Alexander Phillip
• Cicala Stephen Michael
• Suter Charles William
• Sullivan Conor Edward
• Dagci Oguz Hasan

Classifications

• B60W10/02

  including control of driveline clutches · CPC title

• F16D48/062 Primary

  of a clutch system with a plurality of fluid actuated clutches · CPC title

• B60W2710/021

  Clutch engagement state · CPC title

• F16H3/66

  composed of a number of gear trains without drive passing from one train to another · CPC title

• F16D25/14

  Fluid pressure control · CPC title