US4691597A — Control system for a four-speed automatic transmi…

Claim 1

Independent Claim 288 words

A control system for an automatic transmission having four forward speeds and a reverse speed, said automatic transmission including a hydrokinetic torque converter having an integral torsion damper, said automatic transmission including a planetary gear train controlled by three clutches and two brakes, said clutches and brakes each being activated by hydraulic means, said control system comprising: a hydraulic distributor including means for selectively distributing hydraulic fluid to said hydraulic means of said clutches and brakes; four solenoid valves operatively connected to said means for selectively distributing for actuating said means for selectively distributing; and control means sensitive to vehicle operation data for controlling said four solenoid valves, wherein said means for selectively distributing comprises: means for distributing said hydraulic fluid at one of two flow rates for any line pressure by actuation of at least some of said four solenoid valves, three sequence valves each being connectable to a source of hydraulic fluid and having a movable spool connected to a respective one of three of said solenoid valves for distributing said hydraulic fluid, and a progressiveness valve connectable to said source of hydraulic fluid and having a movable spool connected to a fourth of said solenoid valves for distributing said hydraulic fluid, wherein said means for distributing at one of two rates comprises a feed duct for said hydraulic means for said clutches and brakes with a large passage section and including said progressiveness valve, in parallel with a feed duct for said hydraulic means for said clutches and brakes with a small passage section, whereby said hydraulic fluid can be supplied to said hydraulic means at a reduced flow rate by using said progressiveness valve to close said feed duct having said large passage section.

Claim 2

Dependent Claim 288 words

A control system for an automatic transmission having four forward speeds and a reverse speed, said automatic transmission including a hydrokinetic torque converter having an integral torsion damper, said automatic transmission including a planetary gear train controlled by three clutches and two brakes, said clutches and brakes each being activated by hydraulic means, said control system comprising: a hydraulic distributor including means for selectively distributing hydraulic fluid to said hydraulic means of said clutches and brakes; four solenoid valves operatively connected to said means for selectively distributing for actuating said means for selectively distributing; and control means sensitive to vehicle operation data for controlling said four solenoid valves, wherein said means for selectively distributing comprises: means for distributing said hydraulic fluid at one of two flow rates for any line pressure by actuation of at least some of said four solenoid valves, three sequence valves each being connectable to a source of hydraulic fluid and having a movable spool connected to a respective one of three of said solenoid valves for distributing said hydraulic fluid, and a progressiveness valve connectable to said source of hydraulic fluid and having a movable spool connected to a fourth of said solenoid valves for distributing said hydraulic fluid, wherein said means for distributing at one of two rates comprises a feed duct for said hydraulic means for said clutches and brakes with a large passage section and including said progressiveness valve, in parallel with a feed duct for said hydraulic means for said clutches and brakes with a small passage section, whereby said hydraulic fluid can be supplied to said hydraulic means at a reduced flow rate by using said progressiveness valve to close said feed duct having said large passage section.

Claim 3

Dependent Claim 33 words

The system of claim 1 wherein said means for selectively distributing includes means for distributing at a higher of said two rates when at least some of said solenoid valves are not activated.

Claim 4

Dependent Claim 36 words

The system of claim 1 wherein said means for selectively distributing includes means for distributing hydraulic fluid to said clutches and brakes for providing one of said speeds when none of said solenoid valves are activated.

Claim 5

Dependent Claim 98 words

The system of claim 1 wherein said means for selectively distributing further comprise: a first cutoff valve connectable to a source of hydraulic fluid and having a two position spool movable to a position for further distribution of said hydraulic fluid only during a shift from a second to a third of said forward speeds; and a second cutoff valve connectable to a source of hydraulic fluid and having a two position spool movable to a position for further distribution of said hydraulic fluid only during a shift from a third to a fourth of said forward speeds.

Claim 6

Dependent Claim 46 words

The system of claim 4 wherein said means for selectively distributing further includes a manual valve connected in series with said sequence, progressiveness and cutoff valves and having a three position spool for selective further distribution of hydraulic fluid to said sequence, progressiveness and cutoff valves.

Claim 7

Dependent Claim 21 words

The system of claim 1 wherein at least one of the hydraulic means for said clutches and brakes includes an accumulator.

Claim 8

Dependent Claim 13 words

The system of claim 6 wherein said accumulator includes a spring biased piston.

Claim 9

Dependent Claim 54 words

The system of claim 4 wherein said first and second cutoff valves are connected in series with at least one of said sequence valves, including hydraulic potentiometers in ducts connected to each of said cutoff valves, whereby said potentiometers are active only during shifts to, and during operation of, said third and fourth speeds.

Claim 10

Dependent Claim 41 words

The system of claim 8 wherein said hydraulic potentiometers comprise jets in parallel ducts leading to said cutoff valves, at least one of said parallel ducts for each of said potentiometers communicating with said at least one of said sequence valves.

Claim 11

Dependent Claim 26 words

The system of claim 9 wherein the other one of said parallel ducts is connected directly to the output of a pump at a line pressure.

Claim 12

Dependent Claim 268 words

The system of claim 5 including means for providing a hydraulic line pressure and means for adjusting said line pressure, comprising: (a) a pressure control valve, (b) a first spool movable in said pressure control valve, (c) spring means in said pressure control valve for biasing said first spool in a first direction, (d) means for supplying a controlled hydraulic reference pressure to a differential section of said first spool for moving said first spool in a direction opposite said first direction, (e) means for modulating said controlled reference pressure, (f) a second spool in said pressure control valve, said second spool being movable in said direction opposite said first direction into contact with said first spool, (g) means for supplying hydraulic pressure to said second spool for moving said second spool in said direction opposite said first direction, comprising: (i) a first hydraulic line connected to said pressure control valve for supplying hydraulic pressure to said second spool, (ii) said manual valve movable into two of said three positions thereof for selectively connecting said first line to one of said line pressure and zero pressure, (iii) a second hydraulic line connected between said first hydraulic line and a source of said line pressure, (iv) a first restriction in said first line at a position between said manual valve and a point of connection with said second line, and (v) a second restriction in said second line, whereby when said manual valve is in a position for connecting said first line to zero pressure, said first and second restrictions define a second hydraulic potentiometer reducing said line pressure.

Claim 13

Dependent Claim 50 words

The system of claim 11 wherein said means for modulating said controlled reference pressure comprise: a hydraulic line connecting said differential section of said first spool with zero pressure; and a modulating solenoid valve for adjusting a sectional area of said hydraulic line connecting said differential section with zero pressure.

Claim 14

Dependent Claim 49 words

The system of claim 11 including means for selectively subjecting said first spool to said line pressure for moving said first spool in said direction opposite said first direction, and for selectively subjecting said second spool to said line pressure for moving said second spool in said first direction.

Claim 15

Dependent Claim 74 words

The system of claim 13 wherein said means for selectively subjecting comprise: a third line connected to said pressure control valve at a position such that hydraulic pressure therein acts on said first spool in said direction opposite said first direction and acts on said second spool in said first direction; and variable restriction means for selectively communicating said third line with one of said first line pressure and a region at zero pressure.

Claim 16

Dependent Claim 13 words

The system of claim 11 including means for supplying said controlled reference pressure.

Claim 17

Dependent Claim 97 words

The system of claim 15 wherein said means for supplying said controlled reference pressure comprise: a second pressure control valve having at least a third spool slidable therein; second spring means biasing said spool in a second direction; means for supplying hydraulic pressure to said third spool in a direction in opposition to said second direction, whereby movement of said third spool will maintain said hydraulic pressure at said controlled reference pressure; and means for providing a second controlled reference pressure different from said controlled reference pressure and varying as a function of said controlled reference pressure.

Claim 18

Dependent Claim 76 words

The device of claim 16 wherein said means for providing a second controlled reference pressure comprises: a first output conduit at said first controlled reference pressure; a second output conduit connected to said first output conduit and having a first calibrated jet therein; a bypass conduit connected between said second output conduit at a point downstream from said first calibrated jet and a region of zero pressure; and a second calibrated jet in said bypass conduit.

Claim 19

Dependent Claim 107 words

The device of claim 16 wherein said means for providing a second controlled reference pressure comprises: a fourth spool in said second pressure control valve; means for supplying said first controlled reference pressure to said fourth spool for moving said fourth spool in a third direction; third spring means for biasing said fourth spring in a direction opposite said fourth direction; and means for supplying hydraulic pressure to said fourth spool for moving said fourth spool in said direction opposite said fourth direction, whereby movement of said fourth spool will maintain said hydraulic pressure supplied in said direction opposite said fourth direction at said second controlled pressure.

Claim 20

Dependent Claim 14 words

The device of claim 17 wherein said third spool is of a symmetric design.

Claim 21

Dependent Claim 32 words

The system of claim 16 including a third pressure control valve subject to said line pressure and providing a third controlled pressure to the hydrokinetic torque converter and a transmission lubricating circuit.

Claim 22

Dependent Claim 36 words

The system of claim 20 including means associated with said second pressure control valve for selectively cutting off said line pressure to said third pressure control valve when said line pressure drops below a predetermined value.

Claim 23

Dependent Claim 85 words

The system of claim 11 wherein said means for providing a hydraulic line pressure comprises a variable capacity pump having a capacity inversely proportional to a pressure at a pressure line thereof, wherein said pressure line is connected to said first pressure control valve, said first pressure control valve including means for communicating said pressure line with a region of zero pressure when said line pressure decreases below a predetermined value and with said line pressure when said line pressure increases beyond a predetermined value.

Claim 24

Dependent Claim 19 words

The system of claim 22 including means for supplying said second controlled pressure to said first pressure control valve.

Claim 25

Dependent Claim 24 words

The system of claim 12 wherein said modulating solenoid valve is positioned such that a leak orifice thereof is positioned at a top thereof.

Claim 26

Dependent Claim 30 words

The system of claim 3 including means such that said one of said speeds is reverse when said spool of said manual valve is in a first or reverse position.

Claim 27

Dependent Claim 20 words

The system of claim 5 including means such that said manual valve is not in a second or neutral position.

Claim 28

Dependent Claim 30 words

The system of claim 3 including means such that said one of said speeds is a third forward speed when said manual valve is in a third or automatic position.

Claim 29

Dependent Claim 49 words

The system of claim 5 including means such that when only a first and third of said sequence valves are open for further distributing hydraulic fluid, and said manual valve is in an automatic position, said clutches and brakes for said first forward speed are supplied with hydraulic fluid.

Claim 30

Dependent Claim 50 words

The system of claim 5 including means such that when only a first of said sequence valves are open for further distributing hydraulic fluid, and said manual valve is in an automatic position, said clutches and brakes for said first forward speed with engine braking are supplied with hydraulic fluid.

Claim 31

Dependent Claim 49 words

The system of claim 5 including means such that when only a first and second of said sequence valves are open for further distributing hydraulic fluid, and said manual valve is in an automatic position, said clutches and brakes for said second forward speed are supplied with hydraulic fluid.

Claim 32

Dependent Claim 52 words

The system of claim 5 including means such that when only a second of said sequence valves are open for further distributing hydraulic fluid, and said manual valve is in an automatic position, said clutches and brakes for said third forward speed in a power division configuration are supplied with hydraulic fluid.

Claim 33

Dependent Claim 47 words

The system of claim 5 including means such that when only second and third sequence valves are open for further distributing hydraulic fluid, and said manual valve is in an automatic position, said clutches and brakes for said first forward mechanical speed are supplied with hydraulic fluid.

Claim 34

Dependent Claim 53 words

The system of claim 5 including means such that when only a third of said sequence valves are open for further distributing hydraulic fluid, and said manual valves is in an automatic position, said clutches and brakes for said third forward speed in a second power division configuration are supplied with hydraulic fluid.

Claim 35

Dependent Claim 45 words

The system of claim 5 including means such that when none of said sequence valves are open for further distributing hydraulic fluid, and said manual valve is in an automatic position, said clutches and brakes for said fourth mechanical speed are supplied with hydraulic fluid.

Claim 36

Dependent Claim 61 words

The system of claim 5 wherein said control means are constructed such that when said control means senses said vehicle moving forward and senses said manual valve spool moving from an automatic forward position to a reverse position, first and second of said sequence valves are open for further distributing hydraulic fluid to said clutches and brakes for declutching said transmission.

Claim 37

Dependent Claim 21 words

The system of claim 1 including a stop declutching solenoid valve mounted in a fluid bypass of one of said clutches.

Claim 38

Dependent Claim 167 words

A process for control of an automatic transmission having a planetary gear system for four forward speeds with shifting under torque and including first, second and third clutches as well as first and second brakes for said planetary gear system, wherein a forward mechanical third gear is established when hydraulic pressure is fed to all of said clutches, a forward hydraulic second gear is established when hydraulic pressure is fed to a first of said clutches and a second of said brakes, and a forward mechanical fourth gear is established when hydraulic pressure is fed to a third of said clutches and a second of said brakes, said process comprising shifting to said mechanical third gear from one of said hydraulic second gear and said mechanical fourth gear by the steps of: shifting to a power division third gear by establishing hydraulic fluid pressure in said first and third clutches; locking the elements of said planetary gear system by establishing hydraulic fluid pressure in said second clutch.

Claim 39

Dependent Claim 167 words

A process for control of an automatic transmission having a planetary gear system for four forward speeds with shifting under torque and including first, second and third clutches as well as first and second brakes for said planetary gear system, wherein a forward mechanical third gear is established when hydraulic pressure is fed to all of said clutches, a forward hydraulic second gear is established when hydraulic pressure is fed to a first of said clutches and a second of said brakes, and a forward mechanical fourth gear is established when hydraulic pressure is fed to a third of said clutches and a second of said brakes, said process comprising shifting to said mechanical third gear from one of said hydraulic second gear and said mechanical fourth gear by the steps of: shifting to a power division third gear by establishing hydraulic fluid pressure in said first and third clutches; locking the elements of said planetary gear system by establishing hydraulic fluid pressure in said second clutch.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1990-09-07	1991-03-09	1991-09-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1994-09-07	1995-03-09	1995-09-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1998-09-07	1999-03-09	1999-09-08	$7700.00	Window Closed / Lapsed

Control system for a four-speed automatic transmission

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