U.S. patent application number 12/170558 was filed with the patent office on 2009-10-15 for fly-by-wire control for multi-speed planetary transmission.
Invention is credited to Charles F. Long, Charles T. Taylor.
Application Number | 20090258756 12/170558 |
Document ID | / |
Family ID | 41164476 |
Filed Date | 2009-10-15 |
United States Patent
Application |
20090258756 |
Kind Code |
A1 |
Long; Charles F. ; et
al. |
October 15, 2009 |
FLY-BY-WIRE CONTROL FOR MULTI-SPEED PLANETARY TRANSMISSION
Abstract
A fly-by-wire control for a multi-speed vehicle transmission is
provided. Electronic and hydraulic components are provided,
including trim valve systems that are multiplexed by logic valves.
The trim valves and logic valves are self-diagnosing via a
plurality of pressure switches. The control enables single and
double range shifts among the multiple forward speed ratios,
including shifts to and from sixth and higher forward ratios,
reverse and neutral. The control also includes a reduced engine
load at stop feature. In addition, a power off/limp home feature
provides a plurality of failure modes, including a failure mode for
sixth and higher forward speed ratios.
Inventors: |
Long; Charles F.;
(Pittsboro, IN) ; Taylor; Charles T.;
(Indianapolis, IN) |
Correspondence
Address: |
ALLISON TRANSMISSION, INC.
BARNES & THORNBURG LLP, 11 SOUTH MERIDIAN STREET
INDIANAPOLIS
IN
46204
US
|
Family ID: |
41164476 |
Appl. No.: |
12/170558 |
Filed: |
July 10, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61045141 |
Apr 15, 2008 |
|
|
|
Current U.S.
Class: |
477/131 |
Current CPC
Class: |
F16H 61/14 20130101;
Y10T 477/73 20150115; Y10T 477/693635 20150115; F16H 61/0206
20130101; B60W 10/023 20130101; Y10T 477/75 20150115; Y10T 137/8593
20150401; F16H 61/0286 20130101; F16H 61/686 20130101; Y10T
74/20024 20150115; F16H 2200/006 20130101; F16H 61/0202 20130101;
F16H 2045/021 20130101; Y10T 477/635 20150115; F16H 45/02
20130101 |
Class at
Publication: |
477/131 |
International
Class: |
F16H 61/26 20060101
F16H061/26 |
Claims
1. A fly-by-wire control for a vehicle transmission having more
than six forward speeds, the control comprising a plurality of
electro-hydraulic trim valve systems configured to receive
electrical signals and selectively communicate pressurized fluid to
a number of transmission shift mechanisms, wherein the number of
transmission shift mechanisms is greater than the number of
electro-hydraulic trim valve systems, and at least one logic valve
in selective fluid communication with at least one of the trim
valve systems and with at least one of the transmission shift
mechanisms.
2. The control of claim 1, comprising first, second, third and
fourth trim valves, first and second logic valves, and a plurality
of passages configured to selectively fluidly couple the first,
second, third, third and fourth trim valves and the first and
second logic valves to first, second, third, fourth and fifth
transmission shift mechanisms.
3. The control of claim 2, wherein the first and second trim valves
and the first and second logic valves control the first, second and
third transmission shift mechanisms, and the third and fourth trim
valves control the fourth and fifth transmission shift
mechanisms.
4. The control of claim 3, comprising an electronic control and
first, second, third, fourth, fifth, and sixth actuators actuatable
by the electronic control, wherein the first, second, third and
fourth actuators selectively provide output pressure to the first,
second, third and fourth trim valves, respectively, and the fifth
and sixth actuators selectively provide output pressure to the
first and second logic valves, respectively.
5. The control of claim 4, wherein the first and second actuators
are normally high solenoids.
6. The control of claim 5, wherein the fifth and sixth actuators
are normally low, on/off solenoids.
7. The control of claim 4, comprising a seventh actuator actuatable
to provide output pressure to a torque converter flow valve to
selectively control application of a torque converter clutch.
8. The control of claim 7, comprising a reduced engine load at stop
subsystem operably coupled to the torque converter flow valve.
9. The control of claim 8, wherein the reduced engine load at stop
subsystem selectively disengages a torque converter pump clutch
from a drive unit of the vehicle.
10. The control of claim 1, comprising a boost valve in fluid
communication with at least one trim valve system and at least one
of the logic valves.
11. A fly-by-wire control for an automatic transmission of a
vehicle, comprising at least one trim valve system configured to
selectively distribute fluid pressure to at least one transmission
shift mechanism, a first logic valve operable to selectively
distribute fluid pressure to a first transmission shift mechanism,
a second logic valve operable to selectively distributed fluid
pressure to second and third transmission shift mechanisms, first
and second actuators configured to selectively receive electrical
signals from a controller and cause fluid pressure to be applied to
the first and second logic valves, respectively, and a plurality of
passages selectively fluidly coupling the first and second logic
valves to each other, including a first passage configured to
selectively communicate control pressure from one of the logic
valves to the other logic valve and a second passage configured to
selectively communicate main pressure from one of the logic valves
to the other logic valve.
12. The control of claim 11, comprising a check valve in fluid
communication with the first passage.
13. The control of claim 12, wherein the transmission comprises
reverse, neutral, and first through eighth forward ranges, and the
passages and the check valve are configured such that in the event
of a power failure, the neutral and reverse ranges fail to the
neutral range, the first, second, third and fourth forward ranges
fail to the third forward range, and the fifth, sixth, seventh and
eighth forward ranges fail to the sixth forward range.
14. The control of claim 11, wherein the passages selectively
fluidly coupling the first and second logic valves to each other
are arranged such that the first and second logic valves have a
first configuration in which both the first and second logic valves
are in the pressure set position while the second logic valve
distributes fluid pressure to the second shift mechanism and the
trim valve system distributes fluid pressure to a fourth
transmission shift mechanism, and the first and second logic valves
have a second configuration in which the first logic valve is in
the spring set position, the second logic valve is in the pressure
set position, the second logic valve distributes fluid pressure to
the second shift mechanism and the trim valve system distributes
fluid pressure to the fourth transmission shift mechanism.
15. The control of claim 11, wherein the transmission comprises a
reverse range, a neutral range, and a plurality of forward ranges,
the control comprises at least two trim valve systems, and the
passages selectively fluidly coupling the first and second logic
valves to each other are configured such that when the vehicle is
in the neutral range, only one trim valve system is activated.
16. The control of claim 11, wherein the transmission comprises a
reverse range, a neutral range, and first through eighth forward
ranges, and the passages selectively fluidly coupling the first and
second logic valves to each other are configured such that the
first logic valve distributes fluid pressure to the first
transmission shift mechanism when the vehicle is in the first,
second, or third forward range, the second logic valve distributes
fluid pressure to the second transmission shift mechanism when the
vehicle is in the fourth, fifth, or sixth forward range, and the
second logic valve distributes fluid pressure to the third
transmission shift mechanism when the vehicle is in the sixth,
seventh or eight forward range.
17. A fly-by-wire control for an automatic transmission of a
vehicle, comprising a plurality of trim valves, a plurality of
logic valves in selective fluid communication with at least one of
the trim valves and with a plurality of transmission shift
mechanisms, and a plurality of pressure switches operably coupled
to the trim valves and the logic valves to detect the position of
each of the trim valves and the logic valves, wherein the number of
pressure switches equals the number of trim valves and logic
valves.
18. The control of claim 17, comprising first, second, third and
fourth trim valves and first and second logic valves, first,
second, third and fourth pressure switches in fluid communication
with the first, second, third and fourth trim valves, respectively,
and fifth and sixth pressure switches in fluid communication with
the first and second logic valves.
19. The control of claim 18, wherein the first, second, third,
third, and fourth, pressure switches are activated when fluid
pressure is applied to the first, second, third, and fourth trim
valves, respectively, the fifth pressure switch when the first
logic valve is in the spring set position, and the sixth pressure
switch is activated when the second logic valve is in the pressure
set position.
20. The control of claim 17, wherein the pressure switches are
operable to detect changes in the positions of the trim valves and
the logic valves corresponding to single range shifts, double range
shifts, and reverse directions.
Description
RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 61/045,141, filed Apr. 15, 2008, which
is incorporated herein by this reference in its entirety.
TECHNICAL FIELD
[0002] The present invention relates generally to automatic
transmissions for automotive vehicles, and more particularly, to an
electro-hydraulic control for a multi-speed planetary
transmission.
BACKGROUND
[0003] Many types of multi-speed transmissions are available for
motor vehicles. One such type is a six-speed planetary transmission
having clutch-to-clutch shifting controls, as disclosed by Polak in
U.S. Pat. No. 4,070,927. A higher number of forward speed ratios
may be desirable to increase the operating range of the vehicle
engine, improve shift quality, improve fuel economy, or for other
reasons. For example, seven- and eight-speed automatic
transmissions have now been developed. A number of potential
challenges to commercial availability of higher-order transmissions
exist; however, including increased size, complexity and cost of
such transmissions.
[0004] The clutches or other shift mechanisms of automatic
transmissions are typically controlled by electro-hydraulic systems
in which electronic controls selectively actuate hydraulic valves,
which control the distribution of pressurized fluid to engage and
disengage the shift mechanisms upon command. Examples of prior
electro-hydraulic control systems are disclosed in U.S. Pat. Nos.
4,827,806; 5,601,506; 5,616,093; 6,520,881; and 7,140,993, all of
which are issued to Long et al.
SUMMARY
[0005] According to one aspect of the present invention, a
fly-by-wire control for a vehicle transmission having more than six
forward speeds is provided. The control includes a plurality of
electro-hydraulic trim valve systems configured to receive
electrical signals and selectively communicate pressurized fluid to
a number of transmission shift mechanisms, wherein the number of
transmission shift mechanisms is greater than the number of
electro-hydraulic trim valve systems, and at least one logic valve
in selective fluid communication with at least one of the trim
valve systems and with at least one of the transmission shift
mechanisms.
[0006] The control may include first, second, third and fourth trim
valves, first and second logic valves, and a plurality of passages
configured to selectively fluidly couple the first, second, third
and fourth trim valves and the first and second logic valves to
first, second, third, fourth and fifth transmission shift
mechanisms. The first and second trim valves and the first and
second logic valves may control the first, second and third
transmission shift mechanisms, and the third and fourth trim valves
may control the fourth and fifth transmission shift mechanisms. The
control may include an electronic control and first, second, third,
fourth, fifth, and sixth actuators may be actuatable by the
electronic control, wherein the first, second, third and fourth
actuators selectively provide output pressure to the first, second,
third and fourth trim valves, respectively, and the fifth and sixth
actuators selectively provide output pressure to the first and
second logic valves, respectively. The first and second actuators
may be normally high solenoids. The fifth and sixth actuators may
be normally low, on/off solenoids.
[0007] A seventh actuator may provide output pressure to a torque
converter flow valve to selectively control application of a torque
converter clutch. A reduced engine load at stop subsystem may be
operably coupled to the torque converter flow valve. The reduced
engine load at stop subsystem may selectively disengage a torque
converter pump clutch from a drive unit of the vehicle. A boost
valve may be in fluid communication with at least one trim valve
system and at least one of the logic valves.
[0008] According to another aspect of the present invention, a
fly-by-wire control for an automatic transmission of a vehicle is
provided. The control includes at least one trim valve system
configured to selectively distribute fluid pressure to at least one
transmission shift mechanism, a first logic valve operable to
selectively distribute fluid pressure to a first transmission shift
mechanism, a second logic valve operable to selectively distributed
fluid pressure to second and third transmission shift mechanisms,
first and second actuators configured to selectively receive
electrical signals from a controller and cause fluid pressure to be
applied to the first and second logic valves, respectively, and a
plurality of passages selectively fluidly coupling the first and
second logic valves to each other, including a first passage
configured to selectively communicate control pressure from one of
the logic valves to the other logic valve and a second passage
configured to selectively communicate main pressure from one of the
logic valves to the other logic valve.
[0009] The control may include a check valve in fluid communication
with the first passage. The transmission may include reverse,
neutral, and first through eighth forward ranges, and the passages
and the check valve may be configured such that in the event of a
power failure, the neutral and reverse ranges fail to the neutral
range, the first, second, third and fourth forward ranges fail to
the third forward range, and the fifth, sixth, seventh and eighth
forward ranges fail to the sixth forward range. The passages
selectively fluidly coupling the first and second logic valves to
each other may be arranged such that the first and second logic
valves have a first configuration in which both the first and
second logic valves are in the pressure set position while the
second logic valve distributes fluid pressure to the second shift
mechanism and the trim valve system distributes fluid pressure to a
fourth transmission shift mechanism, and the first and second logic
valves may have a second configuration in which the first logic
valve is in the spring set position, the second logic valve is in
the pressure set position, the second logic valve distributes fluid
pressure to the second shift mechanism and the trim valve system
distributes fluid pressure to the fourth transmission shift
mechanism.
[0010] Where the transmission may include a reverse range, a
neutral range, and a plurality of forward ranges, the control may
include at least two trim valve systems, and the passages
selectively fluidly coupling the first and second logic valves to
each other may be configured such that when the vehicle is in the
neutral range, only one trim valve system is activated.
[0011] Where the transmission may include a reverse range, a
neutral range, and first through eighth forward ranges, the
passages selectively fluidly coupling the first and second logic
valves to each other may be configured such that the first logic
valve distributes fluid pressure to the first transmission shift
mechanism when the vehicle is in the first, second, or third
forward range, the second logic valve distributes fluid pressure to
the second transmission shift mechanism when the vehicle is in the
fourth, fifth, or sixth forward range, and the second logic valve
distributes fluid pressure to the third transmission shift
mechanism when the vehicle is in the sixth, seventh or eight
forward range.
[0012] According to another aspect of the present invention, a
fly-by-wire control for an automatic transmission of a vehicle is
provided. The control includes a plurality of trim valves, a
plurality of logic valves in selective fluid communication with at
least one of the trim valves and with a plurality of transmission
shift mechanisms, and a plurality of pressure switches operably
coupled to the trim valves and the logic valves to detect the
position of each of the trim valves and the logic valves, wherein
the number of pressure switches equals the number of trim valves
and logic valves.
[0013] The control may include first, second, third and fourth trim
valves and first and second logic valves, first, second, third and
fourth pressure switches in fluid communication with the first,
second, third and fourth trim valves, respectively, and fifth and
sixth pressure switches in fluid communication with the first and
second logic valves. The first, second, third, and fourth pressure
switches may be activated when fluid pressure is applied to the
first, second, third, and fourth trim valves, respectively, the
fifth pressure switch may be actuated when the first logic valve is
in the spring set position, and the sixth pressure switch may be
activated when the second logic valve is in the pressure set
position. The pressure switches may be operable to detect changes
in the positions of the trim valves and the logic valves
corresponding to single range shifts, double range shifts, and
reverse directions.
[0014] Patentable subject matter may include one or more features
or combinations of features shown or described anywhere in this
disclosure including the written description, drawings, and
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The detailed description refers to the following figures in
which:
[0016] FIG. 1 is a simplified block diagram of a motor vehicle
powertrain including an electro-hydraulic control system for a
multi-speed transmission of a motor vehicle in accordance with the
present invention;
[0017] FIG. 2 is a schematic diagram of one embodiment of a control
system for a multi-speed transmission for a motor vehicle, showing
a fluid passage arrangement and fluid pressure configuration for a
reverse mode of operation of the motor vehicle;
[0018] FIG. 3 is a schematic diagram of the embodiment of FIG. 2,
showing a fluid passage arrangement and fluid pressure
configuration for a neutral mode of operation of the motor
vehicle;
[0019] FIGS. 4-13 are schematic diagrams of the embodiment of FIG.
2, showing fluid passage arrangements and fluid pressure
configurations for various operational ranges of a motor vehicle,
including first through eighth forward speed ratios;
[0020] FIG. 14 is a schematic diagram of the embodiment of FIG. 2,
showing a fluid passage arrangement and fluid pressure
configuration for a reverse or neutral mode of operation of the
motor vehicle when no electrical power is provided to the control
system;
[0021] FIG. 15 is a is a schematic diagram of the embodiment of
FIG. 2, showing a fluid passage arrangement and fluid pressure
configuration for a third forward ratio of the motor vehicle when
no electrical power is provided to the control system;
[0022] FIG. 16 is a is a schematic diagram of the embodiment of
FIG. 2, showing a fluid passage arrangement and fluid pressure
configuration for a sixth forward ratio of the motor vehicle when
no electrical power is provided to the control system; and
[0023] FIG. 17 is a legend indicating fluid pressures depicted in
FIGS. 2-16.
[0024] In general, like structural elements on different figures
refer to identical or functionally similar structural elements,
although reference numbers may be omitted from certain views of the
drawings for ease of illustration.
DETAILED DESCRIPTION
[0025] Aspects of the present invention are described with
reference to certain illustrative embodiments shown in the
accompanying drawings and described herein. While the present
invention is described with reference to the illustrative
embodiments, it should be understood that the present invention as
claimed is not limited to the disclosed embodiments.
[0026] FIG. 1 depicts a simplified logical block diagram of an
electro-hydraulic transmission control 16 in the context of an
exemplary vehicle powertrain 10. Control 16 comprises an
electro-hydraulic apparatus that is capable of providing full
control of an eight speed planetary transmission. Control 16
controls single range shifts, double range (or "skip") shifts,
"garage" shifts, and application and release of a torque converter
clutch, provides a reduced engine load at stop (RELS) feature, and
provides power failure/limp-home protection in multiple ranges, as
described herein. Garage shifts are shifts from neutral to a
forward ratio, from neutral to reverse, or between forward and
reverse. Limp-home refers to the capability of the transmission
control to automatically cause the transmission to assume a
predefined operating range in the event of a transmission power
failure, so that the vehicle can be safely operated or taken out of
operation once the failure is detected.
[0027] Control 16 includes a plurality of logic valves and a unique
latching system that multiplexes a plurality of trim systems, such
that the number of trim systems required to operate the eight-speed
transmission is less than the number of shift mechanisms provided
by the transmission, while still providing all of the features
mentioned above. Trim systems can be costly; therefore, a reduction
in the number of required trim systems may be considered
advantageous, particularly as the number of shift mechanisms in the
transmission increases.
[0028] In FIG. 1, the lines shown as connecting blocks 12, 14, 16,
18, 20, 22, 24, 26, 28 of powertrain 10 represent logical
connections which, in practice, may include one or more electrical,
mechanical and/or fluid connections, passages, couplings or
linkages, as will be understood by those skilled in the art and as
described herein.
[0029] Powertrain 10 includes drive unit 12, torque transferring
apparatus 14, electro-hydraulic transmission control 16,
multi-speed transmission 18 and final drive 20. Drive unit 12
generally provides a torque output to torque transferring apparatus
14. Drive unit 12 may be an internal combustion engine of a
compression-ignition type (i.e. diesel) or a spark-ignition type
(i.e. gasoline), or the like. Torque transferring apparatus 14
selectively establishes a coupling between drive unit 12 and
transmission 18 to convert and/or transfer the torque output from
drive unit 12 to the vehicle transmission 18. As such, torque
transferring apparatus 14 normally includes a fluid coupling such
as a torque converter.
[0030] Transmission 18 includes an input shaft, an output shaft, an
assembly of gears, and a plurality of gear-shifting mechanisms that
are selectively engaged and disengaged by electro-hydraulic
transmission control 16 to cause the vehicle to assume one of a
plurality of operational modes or ranges including at least eight
forward speed ratios, neutral, and reverse. As such, the shift
mechanisms of transmission 18 are in fluid communication with
hydraulic control elements of control 16.
[0031] In this disclosure, the term "shift mechanism" may be used
to refer to one or more clutches, brakes, or other friction
elements or devices, or similar suitable mechanisms configured to
cause the transmission to switch from one range or gear ratio to
another, different range or gear ratio.
[0032] The embodiment of control 16 shown in FIGS. 2-16 relates to
an eight-speed transmission that includes four planetary gearsets
and five shift mechanisms (C1, C2, C3, C4, C5), which are
configured so that two shift mechanisms are applied in any range
(except neutral). A chart showing an example of numerical values
for gear ratios and ratio steps corresponding to the various gear
states of an eight speed transmission having four planetary
gearsets and five shifting mechanisms is provided in Long et al.,
U.S. Provisional Patent Application Ser. No. 61/045,141, filed Apr.
15, 2008, which is incorporated herein by this reference. Those of
ordinary skill in the art will understand that such transmission is
offered only as an example, and that aspects of the present
invention are applicable to other multi-speed transmissions.
[0033] Transmission 18 drives the vehicle load 20. Vehicle load 20
generally includes the drive wheels and driven load mass. The
actual weight of vehicle load 20 may be quite considerable and/or
vary considerably over the course of the vehicle's use, as may be
the case with commercial vehicles such as trucks, buses, emergency
vehicles, and the like.
[0034] Torque transferring apparatus 14 may include one or more
selectively engageable and disengageable couplers such as a torque
converter clutch 26 and/or a pump clutch 28, which may be
configured to alter the coupling between drive unit 12 and
transmission 18. Torque converter clutches (also known as "lockup"
clutches) are often provided to effect unitary rotation of the
torque converter pump and turbine in response to reduced hydraulic
pressure within the torque converter, which may occur when "slip"
(i.e., a difference in rotational speed) between the torque
converter pump and turbine is not required. A pump clutch may be
selectively disengaged to effect a decoupling of the torque
converter pump from the drive unit to reduce the engine load; i.e.,
when the vehicle is idling, decelerating, or operating at lower
speed ratios, for example. Reducing engine load in this manner may
improve fuel efficiency of the vehicle and/or provide other
advantages.
[0035] Couplers 26, 28 of torque transferring apparatus 14 and
shift mechanisms C1, C2, C3, C4, C5 are each configured to
selectively achieve a mechanical, fluid or friction coupling
between components of the powertrain 10 in response to various
conditions or changes in conditions. For instance, one or more of
couplers 26, 28 and shift mechanisms C1, C2, C3, C4, C5 may be
torque transmitting devices or friction devices. One or more of
couplers 26, 28 and shift mechanisms C1, C2, C3, C4, C5 may be
fluid-operated devices such as clutch- or brake-type devices. As
such, one or more of couplers 26, 28 and shift mechanisms C1, C2,
C3, C4, C5 may be stationary- or rotating-type devices.
[0036] In general, each of couplers 26, 28 and shift mechanisms C1,
C2, C3, C4, C5 can be operated independently of each other. For
instance, any combination of couplers 26, 28 and shift mechanisms
C1, C2, C3, C4, and C5 may be engaged and disengaged at a given
time. Such devices 26, 28, C1, C2, C3, C4, C5 may be referred to
individually or collectively herein as "torque transmitting
mechanisms."
[0037] Electrical control 22 controls operation of transmission 18
based on inputs from one or more components of drive unit 12,
torque converter 14, transmission 18, range selector 24; and/or
other inputs. Such inputs may include electrical and/or analog
signals received from sensors, controls or other like devices
associated with the vehicle components. For instance, inputs may
include signals indicative of transmission input speed, driver
requested torque, engine output torque, engine speed, temperature
of the hydraulic fluid, transmission output speed, turbine speed,
brake position, gear ratio, torque converter slip, and/or other
measurable parameters.
[0038] Electrical control 22 generally includes electrical
circuitry configured to process, analyze or evaluate one or more
inputs and issue electrical control signals to electro-hydraulic
control system 16, as needed, through one or more electrical lines,
conductors, or other suitable connections. Such connections may
include hard-wired and/or networked components in any suitable
configuration including, for example, insulated wiring and/or
wireless transmission as may be appropriate or desired.
[0039] Electrical circuitry of control 22 includes computer
circuitry such as one or more microprocessors, integrated circuits
and related elements configured to process executable instructions
expressed in computer programming code or logic, which is stored in
one or more tangible media, i.e., any suitable form of memory or
storage media that is accessible or readable by the processor or
processors. Control 22 may also include analog to digital
converters and/or other signal processing circuitry or devices as
needed to process one or more of the inputs received from the
vehicle components.
[0040] While shown schematically in FIG. 1 as a single block 22, it
will be understood by those skilled in the art that portions of
control 22 may be implemented as separate logical or physical
structures. For example, electronic controls for transmission 18
may be physically and/or logically separated from electronic
controls for drive unit 12.
[0041] Range selector 24 issues signals or commands indicative of a
selected or desired operational mode of the vehicle, i.e., a
selected or desired forward speed ratio, reverse, or neutral. In
the illustrated embodiment, range selector 24 is an
electronically-controlled or "fly-by-wire" range selecting
mechanism, rather than a manual valve selector. Manual valve
selectors require at least some range shift selections to be
mechanically actuated, for example, neutral-to-reverse and
neutral-to-drive. Fly-by-wire systems control range shift
selections electronically. Such electronic controls are based on
signals received from a throttle position sensor or other inputs or
parameters, for example. Other names for this or similar technology
include "shift-by-wire" and "electronic transmission range
selection" (ETRS), as will be understood by those skilled in the
art.
[0042] As shown in FIGS. 2-16, control 16 comprises a plurality of
shift, relay or logic valves X and Y, and a plurality of trim
systems PCS1, PCS2, PCS3, PCS4, wherein the number of trim systems
is less than the number of shift mechanisms being controlled
thereby. Additionally, control 16 comprises a source of pressurized
hydraulic fluid 72, 74, a main or line regulator valve 76, a
control or actuator feed regulator valve 70, a torque converter
flow regulator valve 78, a RELS valve 68, a plurality of pressure
regulator or trim valves 60, 62, 64, 66 (each trim valve being part
of a trim system), a boost valve 80, a plurality of EBF valves 82,
84, a plurality of check valves 88, 90, 92, 94, 96, 98, a lube
regulator valve 86, a plurality of hydraulic accumulators 50, 52,
54, 56, a plurality of orifices or restrictors 116, 118, 120, 122,
124, 126, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148,
150, 152, 154, 156, 158, 160, 162, a plurality of pressure switches
PS1, PS2, PS3, PS4, PS5, PS6, a plurality of electrical actuators
30, 32, 34, 36, 38, 40, 42, 44, 46, and a plurality of
interconnecting fluid passages including a main passage 100, a
control passage 102, a converter feed passage 104, a pump return
passage 106, a plurality of valve feed passages 114, 168, 170, 172,
174, 176, 178, 180, 182, 184, a plurality of valve-to-shift
mechanism passages 190, 192, 194, 196, 198, 200, and a plurality of
valve-to-valve or intermediate passages including passages 210,
212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234. FIG. 17
provides a legend indicating the various fluid pressures shown in
FIGS. 2-16.
[0043] In general, each of main regulator valve 76, actuator feed
regulator valve 70, torque converter flow regulator valve 78, RELS
valve 68, trim valves 60, 62, 64, 66, shift, relay, or logic valves
X and Y, boost valve 80, and lube regulator valve 86 includes a
valve head, a valve spool, at least one valve land interposed
between portions of the valve spool or between the valve head and a
portion of the valve spool, and a return spring disposed in a
spring chamber. Each valve spool is axially translatable in a valve
bore in response to changes in fluid pressure or fluid flow through
the various passages of control 16. For ease of illustration, the
valve bores have been omitted from the figures.
[0044] The valve lands each define a diameter that is greater than
the diameter defined by the valve spool, such that surfaces of the
lands may slidably engage interior surfaces of the valve bore when
the valve spool translates within the valve bore. Spool portions
between valve lands may selectively connect fluid passages to other
fluid passages, or connect fluid passages to fluid chambers,
depending on the position of the valve.
[0045] Each return spring biases its respective valve in a first or
spring set position. Changes in fluid pressure or fluid flow in
selected fluid passages may cause the valve spool to translate
within the valve bore, causing the return spring to partially or
fully compress. Certain of the valves, such as logic valves X and
Y, are slidable between the first or spring set position and a
second or stroked or pressure set position, where the second or
stroked or pressure set position is one in which the return spring
is fully compressed. Others of the valves, such as trim valves 60,
62, 64, 66, are configured to assume intermediate positions between
the first and second positions, in which the return spring is
partially compressed, in addition to the first and second
positions.
[0046] In general, the restrictors or orifices 116, 118, 120, 122,
124, 126, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148,
150, 152, 154, 156, 158, 160, 162 are positioned in various fluid
passages to alter or moderate the rate of fluid flow through the
passages or a portion thereof, in order to control the rate at
which pressure in a fluid passage changes. Such restrictors are
used to provide additional control over fluid pressure in the
passages, or for other reasons.
[0047] Actuators 30, 32, 34, 36, 38, 40, 42, 44, 46 are operably
coupled to control 22 to receive electrical signals (i.e. current)
therefrom and selectively actuate valves 60, 62, 64, 66, 68, 70,
76, 78, X and Y, to attain, maintain, or transition between the
various operational modes of transmission 18. In general, each of
actuators 30, 32, 34, 36, 38, 40, 42, 44, 46 may be a solenoid
valve of either the on/off or variable bleed type. In the
illustrated embodiment, actuators 42 and 44 are on/off solenoids,
while actuators 30, 32, 34, 36, 38, 40, and 46 are of the variable
bleed type.
[0048] Additionally, each of actuators 30, 32, 34, 36, 38, 40, 42,
44, 46 is either of the normally low type or of the normally high
type. A normally low (or normally off) solenoid valve provides
maximum output pressure when it receives electrical input and
provides zero or minimum output pressure when no electrical input
is received; while a normally high (or normally on) solenoid valve
provides maximum output pressure when it is not receiving any
electrical input and provides zero or minimum output pressure when
electrical input is provided. Thus, as used herein, when referring
to an actuator or solenoid valve as being "actuated," this means
either that electrical input is supplied to the solenoid (as in the
case of normally low solenoids) or that electrical input is not
supplied to the solenoid (as in the case of normally high
solenoids). In the illustrated embodiment, actuators 30, 32 and 46
are normally high solenoids while actuators 34, 36, 38, 40, 42, 44
are normally low solenoids.
[0049] In general, pressure switches PS1, PS2, PS3, PS4, PS5, PS6
are each configured to issue an electrical output signal to control
22 when a predetermined fluid pressure is detected by the switch,
for diagnostic purposes or for other reasons. Such electrical
signals inform control 22 of changes in status of components of
control 16. In the illustrated embodiment, the number of pressure
switches in control 16 is less than the number of forward ratios
provided by transmission 18. However, the number of pressure
switches is equal to the total of the number of trim systems and
the number of logic valves in control 16. Due to the use of logic
valves X and Y, the number of pressure switches is one greater than
the number of shift mechanisms (C1, C2, C3, C4, C5) in transmission
18.
[0050] In the illustrated embodiment, pressure switches PS1, PS2,
PS3, PS4 are in fluid communication with trim valves 60, 62, 64,
66, respectively, and pressure switches PS5 and PS6 are in fluid
communication with logic valves X and Y, respectively. Pressure
switches PS1, PS2, PS3, PS4 detect changes in fluid pressure that
are indicative of changes in position of trim valves 60, 62, 64,
66, respectively. Pressure switches PS1, PS2, PS3, PS4 are
activated when the corresponding trim valve 60, 62, 64, 66 is
actuated by control pressure, as shown in the figures.
[0051] Pressure switches PS5 and PS6 detect changes in fluid
pressure that are indicative of changes in position of logic valves
X and Y, respectively. Pressure switch P6 is activated when logic
valve Y is in the pressure set position. However, as a result of
the configuration of restrictors 100 and the latching arrangement
of logic valves X and Y, pressure switch P5 is activated when logic
valve X is in the spring set position. In this way, at any given
time, the particular combination of pressure switches being
activated and deactivated indicates to controller 22 the status of
the trim systems PCS1, PCS2, PCS3, PCS4 and the status of logic
valves X and Y.
[0052] Pressure switches PS5 and PS6 operate as binary switches
that either detect pressure or do not detect pressure in the logic
valves X and Y, and consequently are either on or off at any given
time. Pressure switches PS1, PS2, PS3, PS4, which correspond to the
trim systems PCS1, PCS2, PCS3, PCS4, are activated by the trim
pressure, as shown in Table 2 and Table 3, or by the control or
main pressure, as shown in Table 1. An example of a pressure switch
that is activated whenever its associated valve is in either a
"trim" state or an "on" state is disclosed in Long et al., U.S.
Pat. No. 6,382,248.
[0053] Actuators 30, 32, 34, 36, 38, 40, 42, 44, 46, and pressure
switches PS1, PS2, PS3, PS4, PS5, PS6 are in electrical or
electronic communication with control 22 by suitable electrical
wiring, electric networks, and/or wireless channels, as will be
understood by those skilled in the art. However, for ease of
illustration, logical representations of many of these electrical
connections have been omitted from FIGS. 2-16.
[0054] During operation of the vehicle, pump 72 draws hydraulic
fluid from fluid supply, sump or reservoir 74 and supplies it to
main regulator valve 76. Main regulator valve 76 distributes the
fluid to main passage 100 at a main or "line" pressure. In general,
the main pressure defines a range including a minimum system
pressure and a maximum system pressure for main passage 100. In the
illustrated embodiment, the main pressure is in the range of about
50-250 pounds per square inch (psi).
[0055] Main regulator valve 76 distributes fluid at the main
pressure to actuator feed regulator valve 70, RELS valve 68, second
trim valve 62, and second logic valve Y, directly through main
passage 100.
[0056] Main regulator valve 76 is in fluid communication with main
modulator actuator 46 via passage 114. Actuator 46 is also in fluid
communication with control passage 102. Actuator 46 is actuated by
electronic or electrical control 22 to modulate or control the
fluid pressure level in main passage 100 via main regulator valve
76.
[0057] Control 22 selectively provides signals to actuator 46 based
on engine output-torque, throttle position, or other parameters or
factors. The output pressure of actuator 46 in passage 114 is
variable and less than the main pressure. In the illustrated
embodiment, actuator 46 is a normally high solenoid valve with an
output pressure in passage 114 varying in the range of about 0-110
psi.
[0058] When fluid pressure in main passage 100 is satisfied, main
regulator valve 76 distributes fluid pressure to converter feed
passage 104, which is in fluid communication with converter flow
valve 78, relief valve 98 and lube regulator valve 86. Converter
flow valve 78 distributes fluid in passage 104 to fluid chamber 108
of torque converter 14.
[0059] Converter flow valve 78 and/or relief valve 98 distributes
fluid from passage 104 to cooler system 110. In general, cooler
system 110 is operable to maintain the temperature of the hydraulic
fluid within a suitable temperature range. In the illustrated
embodiment, the operating temperature of the hydraulic fluid is in
the range of about -40 degrees Celsius to about +120 degrees
Celsius.
[0060] Lube regulator valve 86 distributes fluid from passage 104
and/or cooler 110 to lubrication system fluid chamber 112. Lube
system fluid chamber 112 provides fluid to lubricate various
components of the transmission 18, such as components of the
planetary gear sets including gears and bearings.
[0061] Relief valve 98 prevents overpressure of converter 14,
during a cold startup, for example. After the fluid requirements of
torque converter fluid chamber 108, lube system fluid chamber 112
and cooler system fluid chamber 110 are met, any remaining fluid
may be returned to pump return passage 106. During "normal"
operation in which pump 72 is drawing fluid from reservoir 74,
fluid in pump return passage 106 is at a negative pressure. In the
illustrated embodiment, the negative pressure is in the range of
about -2 psi.
[0062] The fluid pressure in converter feed passage 104, which may
be referred to as the "converter" pressure, is generally less than
the main pressure. In the illustrated embodiment, the converter
pressure is in the range of about 100 psi.
[0063] Actuator feed regulator valve 70 and actuator 46 are in
direct fluid communication with, and thereby maintain fluid at a
"control" pressure, in control passage 102. Control passage 102 is
in direct fluid communication with, and thereby supplies control
pressure to, actuators 30, 32, 34, 36, 38, 40, 42, 44, and 46,
boost valve 80, and check valves 88, 90, 92. The control pressure
is generally less than the main pressure and greater than the
converter pressure. In the illustrated embodiment, the control
pressure is in the range of about 110 psi.
[0064] A torque converter clutch control subsystem, TCC, includes
actuator 40, fluid passage 180, and torque converter flow valve 78.
The TCC subsystem controls engagement and disengagement of the
torque converter clutch or "lockup" clutch 26. To apply the torque
converter clutch 26, pressure in the torque converter fluid chamber
108 is reduced. The pressure in chamber 108 is reduced by actuating
actuator 40 to provide control pressure in passage 180, thereby
applying control pressure to valve head 186 of converter flow valve
78, causing valve 78 to move to the pressure set position shown in
FIGS. 7-13. When valve 78 is in the pressure set position, land 188
opens converter fluid chamber 108 to exhaust to apply the clutch
26. As shown by Table 1, in the illustrated embodiment, the torque
converter clutch 26 is applied in the 3.sup.rd through 8.sup.th
forward ratios and released in the reverse, neutral, first and
second ranges of the transmission 18. However, since the torque
converter clutch 26 is controlled independently of the other
clutches, it may be applied or released at any time, including
during neutral and reverse. For example, torque converter clutch 26
may be applied during power take-off (PTO) applications.
[0065] In the illustrated embodiment, actuator 40 is a normally low
solenoid. As such, when actuator 40 is not actuated, control 22
provides little or no electrical input to actuator 40, and the
output pressure of actuator 40 is zero or nearly zero psi. To
actuate actuator 40, control 22 supplies electrical input to
actuator 40, and the output pressure of actuator 40 is at or near
the control pressure.
[0066] A reduced engine load at stop subsystem, RELS, includes
actuator 38, RELS valve 68, passage 210, and torque converter flow
valve 78. In general, a reduced engine load at stop system is a
control that enables an additional mechanical disconnection between
the drive unit 12 and the torque converter 14 to achieve greater
engine efficiency when it is desired to slow, stop or idle the
vehicle. When the RELS system is activated the additional
disconnection is provided by mechanically decoupling the drive unit
12 from the torque converter pump (in addition to the mechanically
decoupling of the pump from the turbine, which is accomplished by
release of the torque converter clutch 26). In the illustrated
embodiment, the RELS feature is provided by disengaging the pump
clutch 28 of the torque converter 14 while the torque converter
clutch 26 is also disengaged. Additional description of a control
for a torque converter having both a torque converter clutch and a
pump clutch may be found in Long et. al., U.S. Provisional Patent
Application Ser. No. 61/045,141, filed Apr. 15, 2008, which is
incorporated herein by this reference. An example of a reduced
engine load at stop control may be found in U.S. Pat. No. 7,338,407
to Long et al., issued Mar. 4, 2008. In general, RELS valve 68 is
multiplexed via actuators 38, 40 to control both the torque
converter clutch 26 and the pump clutch 28.
[0067] An example of an activation of the RELS feature in the first
forward ratio is shown in FIG. 4. Torque converter clutch 26 is
disengaged, as converter flow valve 78 is in the spring set
position and converter fluid chamber 108 is at the converter
pressure. To activate the RELS feature, actuator 38 is actuated,
providing control pressure in passage 178, which is applied to the
valve head 204. Stroking the RELS valve 68 causes land 206 to open
passage 210 to connect with main passage 100, thereby providing
main pressure to RELS hydraulic fluid chamber 202. The pressure
increase in RELS fluid chamber 202 causes pump clutch 28 to
disengage.
[0068] In the illustrated embodiment, actuator 38 is a normally low
solenoid. As such, when actuator 38 is not actuated, control 22
provides little or no electrical input to actuator 38, and the
output pressure of actuator 38 is zero or nearly zero psi. To
actuate actuator 38, control 22 supplies electrical input to
actuator 38. When actuated, the output pressure of actuator 38 is
at or near the control pressure.
[0069] The shift mechanisms, i.e., C1, C2, C3, C4, C5 of
transmission 18 are controlled by trim systems PCS1, PCS2, PCS3,
and PCS4. Each of the trim systems PCS1, PCS2, PCS3, and PCS4
includes an actuator 30, 32, 34, 36, a trim valve 60, 62, 64, 66, a
trim valve feed passage 170, 172, 174, 176, a restrictor 122, 124,
120, 118 disposed in passages 170, 172, 174, 176, an accumulator
50, 52, 54, 56, and a pressure switch PS1, PS2, PS3, PS4.
[0070] Trim system PCS1 includes actuator 30, accumulator 50, trim
valve 60, feed passage 170, restrictor 122, pressure switch PS1,
valve-to-shift mechanism passage 218, which is in fluid
communication with shift mechanism fluid chamber C2 via logic valve
Y. Restrictors 134, 156 are disposed in passage 218, with
restrictor 134 being disposed nearer to trim valve 60 and
restrictor 156 being disposed nearer to the inlet to fluid chamber
C2.
[0071] In the illustrated embodiment, actuator 30 is a normally
high solenoid valve. As such, when control 22 provides little or no
electrical input to actuator 30, the output pressure of actuator 30
in passage 170 is at or near the control pressure. When control 22
supplies electrical input to actuator 30, the output pressure of
actuator 30 is zero or nearly zero psi.
[0072] Trim system PCS2 includes actuator 32, accumulator 52, trim
valve 62, feed passage 172, restrictors 124, 136, 148, pressure
switch PS2, valve to valve passage 220, which is in fluid
communication with boost valve 80, valve to valve passage 222,
which is in fluid communication with logic valve X, and valve to
valve passage 236, which is in fluid communication with logic valve
Y.
[0073] In the illustrated embodiment, actuator 32 is a normally
high solenoid valve. As such, when control 22 provides little or no
electrical input to actuator 32, the output pressure of actuator 32
in passage 172 is at or near the control pressure. When control 22
supplies electrical input to actuator 32, the output pressure of
actuator 32 is zero or nearly zero psi.
[0074] Boost valve 80 is in fluid communication with fluid chamber
C5b via valve to shift mechanism passage 200. Restrictor 138 is
disposed in passage 200 near the inlet to fluid chamber C5b. In
general, boost valve 80 is actuated whenever trim valve 62 reaches
a predetermined level (which may be set by adjusting the return
spring on boost valve 80). The predetermined pressure level is set
to ensure that the clutch C5 is fully applied. In the illustrated
embodiment, the predetermined level of trim valve 62 for activating
boost valve 80 is in the range of about 50 to about 60 psi. As
boost valve 80 is in fluid communication with both chamber C5a and
C5b, boost valve 80 is configured as a dual area activation valve
similar to one disclosed in Long et al., U.S. patent application
Ser. No. ______, filed Aug. 24, 2007 (Attorney Docket No.
P001573).
[0075] Logic valve X is in fluid communication with fluid chamber
C5a via valve to shift mechanism passage 198. Restrictor 162 is
disposed in passage 198 near the inlet to fluid chamber C5a. Logic
valve X is also in fluid communication with fluid chamber C5b via
passage 198 and boost valve 80. Actuator 42 is operably coupled to
logic valve X. In the illustrated embodiment, actuator 42 is a
normally low solenoid. As such, when actuator 42 is not actuated,
control 22 provides little or no electrical input to actuator 42,
and the output pressure of actuator 42 is zero or nearly zero psi.
To actuate actuator 42, control 22 supplies electrical input to
actuator 42. When actuated, the output pressure of actuator 42 to
valve head 250 is at or near the control pressure.
[0076] Logic valve Y is in fluid communication with shift mechanism
fluid chamber C1 via valve to shift mechanism passage 190.
Restrictor 158 is disposed in passage 190 near the inlet to fluid
chamber C1. Logic valve Y is also in fluid communication with shift
mechanism fluid chamber C2 via passage 192. Restrictor 156 is
disposed in passage 192 near the inlet to fluid chamber C2. Logic
valve Y is actuated by actuator 44. In the illustrated embodiment,
actuator 44 is a normally low solenoid. As such, when control 22
supplies electrical input to actuator 44, actuator 44 outputs the
control pressure to valve head 252. Both of actuators 42, 44 are
on/off solenoid valves.
[0077] Logic valves X and Y are in fluid communication with each
other via a plurality of valve to valve passages 224, 226, 228,
230, 232, 234, 236. Check valve 94 is disposed in passage 224. In
this way, trim systems PCS1 and PCS2 are multiplexed via logic
valves X and Y to selectively control the engagement and
disengagement (or application and release) of shift mechanisms C1,
C2, and C5.
[0078] Trim system PCS3 selectively controls engagement and
disengagement of shift mechanism C3. Trim system PCS3 includes
actuator 34, accumulator 54, trim valve 64, pressure switch PS3,
feed passage 174, restrictor 120 disposed in feed passage 174,
valve to shift mechanism passage 194 and restrictor 132 disposed in
passage 194 near the inlet to shift mechanism fluid chamber C3.
Actuator 34 is a normally low solenoid. As such, when control 22
provides little or no electrical input to actuator 34, the output
pressure of actuator 34 is zero, nearly zero psi, or, for VBS
solenoids, the exhaust backfill (EBF) pressure. When control 22
supplies electrical input to actuator 34, the output pressure of
actuator 34 in passage 174 is at or near the control pressure.
[0079] Trim system PCS4 selectively controls engagement and
disengagement of shift mechanism C4. Trim system PCS4 includes
actuator 36, accumulator 56, trim valve 66, pressure switch PS4,
feed passage 176, restrictor 118 disposed in feed passage 176,
valve to shift mechanism passage 196 and restrictor 150 disposed in
passage 196 near the inlet to shift mechanism fluid chamber C4.
Actuator 36 is a normally low solenoid. As such, when control 22
provides little or no electrical input to actuator 36, the output
pressure of actuator 36 is zero, nearly zero psi, or, for VBS
solenoids, the exhaust backfill (EBF) pressure. When control 22
supplies electrical input to actuator 36, the output pressure of
actuator 36 in passage 176 is at or near the control pressure.
[0080] In the illustrated embodiment, an accumulator 50, 52, 54, 56
is in fluid communication with each of the trim systems PCS1, PCS2,
PCS3, PCS4. Such accumulators or similar devices may be used to
hydraulically filter step changes in the output pressure of the
respective actuators 30, 32, 34, 36, or for other purposes.
However, it will be understood by those skilled in the art that the
inclusion of accumulators 50, 52, 54, 56 is considered
optional.
[0081] Table 1 shows the components of control 16 that are actuated
when each of the various operational modes of transmission 18 are
achieved. Table 1 also shows the shift mechanism(s) and torque
converter coupler(s) that are activated in each mode. The asterisk
is used to denote that what is shown is a typical configuration;
however, the torque converter clutch can be engaged in any
range.
TABLE-US-00001 TABLE 1 STEADY STATE MECHANIZATION Torque Shift Trim
Logic Pressure Converter Pump Mechanism(s) System(s) Valve(s)
Switche(s) Clutch Clutch Range Applied Actuated Actuated Actuated
Status* Status Reverse C2, C5 PCS1, X PS1, PS2 Released Applied
PCS2 Neutral C5 PCS2 None PS5, PS2 Released Applied 1.sup.st C5, C3
PCS2, X, Y PS6, PS2, Released Applied PCS3 PS3 RELS 1.sup.st C5, C3
PCS2, X, Y PS6, PS2, Released Released PCS3 PS3 2.sup.nd C5, C4
PCS2, X, Y PS6, PS2, Released Applied PCS4 PS4 3.sup.rd C1, C5
PCS1, X, Y PS6, PS1, Applied Applied PCS2 PS2 4.sup.th C1, C4 PCS1,
X, Y PS6, PS1, Applied Applied PCS4 PS4 4.sup.th, C1, C4 PCS1, Y
PS5, PS6, Applied Applied PCS4 PS1, PS4 5.sup.th, C1, C3 PCS1, Y
PS5, PS6, Applied Applied PCS3 PS1, PS3 6.sup.th, C1, C2 PCS1, Y
PS5, PS6, Applied Applied PCS2 PS1, PS2 7.sup.th, C2, C3 PCS2, Y
PS5, PS6, Applied Applied PCS3 PS2, PS3 8.sup.th, C2, C4 PCS2, Y
PS5, PS6, Applied Applied PCS4 PS2, PS4
[0082] Another chart showing additional details of the steady state
mechanization is provided in Long et al., U.S. Provisional Patent
Application Ser. No. 61/045,141, filed Apr. 15, 2008, which is
incorporated herein by this reference. The configuration of control
16 during the modes shown in Table 1 above will now be
described.
[0083] Reverse
[0084] When the reverse operational mode is requested, e.g. by
range selector 24, control 16 assumes the configuration shown in
FIG. 2, in which fluid chambers C2, C5a and C5b are pressurized and
pressure switches PS1 and PS2 detect control pressure. Control
pressure is applied to valve heads 240, 242, and 250, by actuation
of actuators 32, 32, and 42, of trim systems PCS1, PCS2, and logic
valve X, respectively. Check valve 94 prevents control pressure
from entering passage 224.
[0085] Actuation of actuator 30 causes downward translation of
valve 60, thereby causing land 256 to move. As a result, pressure
switch PS1 is connected to control passage 102 via valve to valve
passage 238, thereby causing PS1 to detect the control pressure.
Movement of lands 256, 258 connects valve to valve passage 218 with
valve to valve passage 208. With logic valve Y in the spring set
position, valve to shift mechanism passage 192 is connected to
valve to valve passage 218. Downward translation of logic valve X
moves lands 278, 280 so that passages 208, 226 are connected to
main passage 100. As a result, main pressure is applied to fluid
chamber C2 via restrictor 156. Restrictor 156 moderates the rate of
application of main pressure to fluid chamber C2 to provide a
smoother application of the corresponding shift mechanism, C2.
[0086] Actuation of actuator 32 applies control pressure to valve
head 242 of trim valve 62. Downward translation of trim valve 62
causes land 262 to move so that pressure switch PS2 is connected to
control passage 102, thereby causing PS2 to detect the control
pressure. Movement of lands 262, 264 connects valve to valve
passage 222 with main passage 100, thereby applying main pressure
to fluid chambers C5a and C5b via passage 198 and restrictors 136,
138 and 162. With valve 62 actuated, spool portion 328 is
interposed in fluid passage 220, causing control pressure to be
applied to boost valve 80. As a result, lands 308, 310 move so that
fluid chamber C5b is connected with passage 198. Thus, in the
reverse mode, actuation of trim valves 60, 62, boost valve 80, and
logic valve X results in the engagement of shift mechanisms C2 and
C5.
[0087] Neutral
[0088] When the neutral operational mode is requested, e.g. by
range selector 24, control 16 assumes the configuration shown in
FIG. 3. In neutral, only one shift mechanism, C5 is actuated, via
actuation of trim system PCS2 and boost valve 80 as described
above. None of the other trim systems PCS2, PCS3, PCS4 are
actuated, and neither of the logic valves X and Y are actuated.
However, fluid chambers C5a and C5b remain pressurized, and
pressure switch PS5 is actuated. Check valves 90, 92 retain control
pressure in passage 102 and prevent it from affecting the
configuration of valves 60, 64.
[0089] With both logic valves X and Y in the spring set position,
passage 208 is connected with passage 228 (rather than passage 226,
as in FIG. 2). Passage 228 connects with passage 238, which
connects with exhaust passage 332, which is exhausted via EBF valve
82. EBF valve 82 provides the exhaust backfill pressure, which is a
generally pressure to prevent air from entering exhausted clutches.
In the illustrated embodiment, the exhaust backfill pressure is in
the range of about 2 psi. Movement of land 286 opens passage 236 to
connect with spring chamber 330, which is at the exhaust pressure.
De-activation of trim system PCS1 (relative to FIG. 2) and the
resulting movement of lands 254, 256, 258, connects passage 218
with exhaust passage 326, which is exhausted via EBF valve 84.
Fluid chamber C2 is thereby exhausted. Restrictor 156 moderates the
rate of exhaustion to provide smoother disengagement of shift
mechanism C2.
[0090] Movement of land 280 results in connection of pressure
switch PS5 with passage 226, which is at the main pressure by
virtue of its connection to main passage 100 and the presence of
check valve 96 in passage 216. Thus, PS5 is actuated. A series of
restrictors 160 and land 286 prevent main pressure from entering
passage 234.
[0091] While shift mechanism C5 remains actuated in both the
reverse and neutral positions, shown in FIGS. 2 and 3, different
configurations of the fluid passages are used to accomplish this.
Whereas in FIG. 2, fluid chamber C5a is in direct fluid
communication with passages 222 and 198, in FIG. 3, fluid chamber
C5a is in fluid communication with passage 222 via passages 230,
232.
[0092] First Forward Ratio
[0093] When the first forward ratio is requested, e.g.
automatically by control 22 or by range selector 24, control 16
assumes the configuration shown in FIG. 5. Control pressure is
applied to valve heads 242, 244, 250 and 252 causing movement of
trim valves 62, 64 and logic valves X and Y. Relative to the
neutral configuration shown in FIG. 3, the configuration of trim
system PCS2 remains the same. However, in the first forward ratio
shown by FIG. 5, control pressure applied to valve head 250 as a
result of actuation of actuator 42 of logic valve X is routed
through check valves 94, 96 and passages 224, 216. Passage 216 is
in fluid communication with control passage 102. Also, even though
the positions of logic valves X and Y have changed relative to the
neutral mode, due to the latching arrangement of the logic valves X
and Y, shift mechanism fluid chambers C5a and C5b remain
pressurized and shift mechanism C5 remains engaged.
[0094] Activation of trim system PCS3 downwardly translates lands
266, 268, 270 such that pressure switch PS3 is connected to control
passage 102. Pressure switch PS3 therefore is activated by the
control pressure. Also, valve to shift mechanism passage 194 is
connected to passage 208. By virtue of activation of logic valves X
and Y, which are now both in the pressure set position, passage 208
is in fluid communication with main passage 100 through
intermediate passage 226. Accordingly, main pressure is provided to
shift mechanism fluid chamber C3 to engage shift mechanism C3. Main
pressure is also provided to pressure switch PS6 as the downward
translation of logic valve Y connects PS6 with main passage 100.
Spool portion 334 of valve 64 prevents main pressure from affecting
the position of check valve 90. In comparison to FIG. 2, which
shows the RELS subsystem in an activated state; in the "normal"
first forward ratio shown by FIG. 3, the RELS fluid chamber 202 is
not pressurized because actuator 38 and valve 68 are not
actuated.
[0095] Second Forward Ratio
[0096] When the second forward ratio is requested, e.g.
automatically by control 22 or by range selector 24, control 16
assumes the configuration shown in FIG. 6. In the second forward
ratio, the configuration of PCS1, PCS2, and logic valves X and Y
remains the same as in the first forward ratio. PCS3 is not
actuated, assuming the same position as in FIG. 2. Fluid chamber C3
and pressure switch PS3 are exhausted, indicating release of shift
mechanism C3. Control 22 sends electrical input to actuator 36 to
actuate PCS4. Control pressure applied to valve head 246 causes
downward translation of lands 272, 274, 276. As a result, pressure
switch PS4 is connected with control passage 102 via passage 216.
Pressure switch PS4 is thereby activated by control pressure. Also,
valve to shift mechanism passage 196 is connected with main passage
100 via passages 208, 226, 228. Shift mechanism fluid chamber C4
therefore receives main pressure via restrictors 128, 150.
Restrictors 128, 150 moderate the rate at which main pressure is
received by fluid chamber C4 to provide smoother on-coming of shift
mechanism C4. Restrictor 142 prevents main pressure from entering
passage 338. With spool portion 336 interposed in passage 338 as a
result of activation of trim system PCS4, fluid in passage 338 is
at the control pressure. Check valve 88 connects passage 338 with
control passage 102.
[0097] Third Forward Ratio
[0098] When the third forward ratio is requested, e.g.
automatically by control 22 or by range selector 24, control 16
assumes the configuration shown in FIG. 7. In the third forward
ratio, PCS2 and logic valves X and Y maintain the same position as
in the first and second ratios. PCS1 is actuated, connecting PS1
with control pressure in the same manner as described above with
reference to FIG. 2. However, with logic valve Y in the pressure
set position, passage 218 is in fluid communication with valve to
shift mechanism passage 190. Thus, main pressure is applied to
fluid chamber C1 through restrictor 158 to engage shift mechanism
C1. Trim system PCS4 is deactuated, assuming the same configuration
as shown in FIG. 2, described above, to release shift mechanism
C4.
[0099] Also, in the third forward ratio, torque converter clutch 26
is applied as described above. The torque converter clutch 26
normally remains applied in the third through eighth forward
ratios. The pump clutch 28 is normally applied in all ranges,
unless the RELS features is activated as shown, for example, in
FIG. 4.
[0100] Fourth Forward Ratio
[0101] When the fourth forward ratio is requested, e.g.
automatically by control 22 or by range selector 24, control 16
assumes the configuration shown in FIG. 8. In the fourth forward
ratio, the position of logic valves X and Y remains the same as in
FIGS. 4-7, but trim system PCS2 is deactuated. Deactuation of PCS2
causes upward translation of valve 62. As a result, land 264
disconnects passage 222 from main passage 100. Also, removal of C5
clutch feedback pressure from passage 220 deactuates boost valve
80. As a result, shift mechanism fluid chambers C5a and C5b are
exhausted and shift mechanism C5 is disengaged. Trim system PCS4 is
actuated to apply shift mechanism C4 in a similar manner as shown
in FIG. 6, described above.
[0102] Alternative Fourth Forward Ratio
[0103] An alternative fourth forward ratio may be requested, either
automatically by control 22 or by range selector 24, when it is
desired to transition the transmission 18 from the first set of
forward ratios 1-4 to the second set of forward ratios 5-8, or for
other reasons. In Table 1, the ratios denoted by "prime" are ratios
in which logic valve X is destroked. Logic valve X is stroked for
the lower ranges and destroked for the upper ranges. As such,
limp-home capabilities are provided in the lower and upper
ranges.
[0104] In the illustrated alternative fourth forward ratio, control
16 assumes the configuration shown in FIG. 9. In the alternative
fourth forward ratio, logic valve X is deactuated, while the trim
systems PCS1, PCS2, PCS3, PCS4 and logic valve Y all maintain the
same position as in FIG. 8. Removal of control pressure from valve
head 250 shifts logic valve X into the spring set position.
Movement of lands 278, 280, 282 alters the connections of passages
226, 228 without affecting the status of pressure switch PS6.
Pressure switch PS6 remains connected to main pressure, however
passage 228 (rather than passage 226, as in FIG. 8) is in fluid
communication with passage 208. Pressure switch PS5 is connected
with passage 226, and pressure switch PS5 is activated by main
pressure. Restrictors 160 retain the main pressure in PS6. In this
way, four pressure switches are activated, whereas in the lower
forward ratios described above, three pressure switches are
activated.
[0105] Fifth Forward Ratio
[0106] When the fifth forward ratio is requested, e.g.
automatically by control 22 or by range selector 24, control 16
assumes the configuration shown in FIG. 10. In the fifth forward
ratio, trim systems PCS1, PCS2 and logic valves X and Y maintain
the same position as in FIG. 9. Trim system PCS3 is actuated to
apply shift mechanism C3 in a similar manner to FIG. 5, described
above. Trim system PCS4 is deactivated in a similar manner to FIG.
7, described above, releasing shift mechanism C4 and deactivating
pressure switch PS4.
[0107] Sixth Forward Ratio
[0108] When the sixth forward ratio is requested, e.g.
automatically by control 22 or by range selector 24, control 16
assumes the configuration shown in FIG. 11. PCS1 and logic valve Y
are actuated as in FIG. 10, maintaining engagement of shift
mechanism C1 and pressure switches PS1 and PS6. PCS3 is deactivated
in a similar manner as shown in FIG. 2, described above, thereby
releasing shift mechanism C3. Logic valves X and Y are in the same
positions as in FIG. 10 (logic valve X in pressure set, logic valve
Y in spring set), however activation of PCS2 (and thereby, boost
valve 80) pressurizes lines 216 and 222. Pressure switch PS2 is
thereby activated by control pressure and shift mechanism fluid
chamber C2 receives main pressure via passages 232, 192 and
restrictor 156. Shift mechanism C2 is thereby engaged along with
C1. The latching arrangement of logic valves X and Y permits
engagement of C2 and C1 while the logic valves X and Y are in the
same position as in FIG. 10. Also, the arrangement of fluid
passages between logic valves X and Y permits engagement of C1 and
C2 while C5 is disengaged, as shown in FIG. 11, and also permits
engagement of C2 and C5 while C1 is disengaged, as shown in FIG.
2.
[0109] Seventh Forward Ratio
[0110] When the seventh forward ratio is requested, e.g.
automatically by control 22 or by range selector 24, control 16
assumes the configuration shown in FIG. 12. In the seventh forward
ratio, trim system PCS1 is deactuated, releasing shift mechanism C1
and deactivating pressure switch PS1 as described above. PCS3 is
actuated, activating pressure switch PS3 and engaging shift
mechanism C3 as described above. The positions of trim systems
PCS1, PCS2, and logic valves X and Y remain the same as in FIG.
11.
[0111] Eighth Forward Ratio
[0112] When the eighth forward ratio is requested, e.g.
automatically by control 22 or by range selector 24, control 16
assumes the configuration shown in FIG. 13. In the eighth forward
ratio, trim system PCS3 is deactuated, releasing shift mechanism C3
and deactivating pressure switch PS3 as described above. PCS4 is
actuated, activating pressure switch PS4 and engaging shift
mechanism C4 as described above. The positions of trim systems
PCS1, PCS2, and logic valves X and Y remain the same as in FIGS. 11
and 12.
[0113] Failure Modes
[0114] FIGS. 14-16 illustrate configurations of control 16 in three
different failure modes. FIG. 14 illustrates the configuration of
control 16 when the vehicle is in either reverse or neutral at the
time of power failure. In either of these situations, the
transmission fails to neutral. FIG. 15 illustrates the
configuration of control 16 when the vehicle is in one of the
first, second, third or fourth forward ratios at the time of power
failure. In any of these situations, the transmission assumes the
third forward ratio after the power failure. FIG. 16 illustrates
the configuration of control 16 when the vehicle is in one of the
fifth, sixth, seventh or eighth forward ratios at the time of power
failure. In any of these situations, the transmission assumes the
sixth forward ratio after the power failure. Accordingly, control
16, including the particular configuration of logic valves X and Y
and interconnecting fluid passages, provides a number of measures
in the event of an electrical failure.
[0115] In the illustrated embodiment, actuators 30, 32, and 46 are
normally high solenoids, while the remaining actuators 34, 36, 38,
40, 42, 44 are normally low solenoids. As a result, in the event of
a power failure, main passage 100 is able to maintain the main
pressure, control passage 102 is able to maintain the control
pressure and trim systems PCS1, PCS2 are actuated as described
above.
[0116] As shown in FIG. 14, the activation of PCS1 in the power
off/limp home mode for reverse to neutral allows the system to
maintain the same arrangement of control 16 and transmission 18 as
in the "normal" neutral mode shown in FIG. 3, except that pressure
switch PS1 receives control pressure from passage 102 via passage
238. Even though PCS1 is activated, shift mechanism C2 is not
pressurized (as it would be in the normal reverse mode, shown in
FIG. 2), because logic valve X is not actuated.
[0117] As compared to the "normal" third forward ratio, FIG. 15
shows that the torque converter clutch 26 is disengaged in the limp
home third ratio, since actuator 40 is not actuated. Pump clutch 28
remains engaged because the RELS fluid chamber is not required to
be pressurized to engage pump clutch 28. Also, with power off, even
though actuators 42, 44 are not actuated, logic valves X and Y are
able to maintain the same position as in normal third ratio (FIG.
7) because control pressure is provided to passage 216 due to
continued activation of trim system PCS2. The control pressure acts
upon a differential area of land 290 to maintain the position of
logic valve Y (relative to the normal third range). The control
pressure is also applied to valve head 250 via passage 224 and
check valve 94, to maintain the position of logic valve X (relative
to the normal third range).
[0118] The arrangement of fluid passages between logic valves X and
Y is used in a similar manner in the limp home sixth forward ratio.
As compared to the "normal" sixth forward ratio, FIG. 16 shows that
the torque converter clutch 26 is disengaged in the limp home sixth
ratio, since actuator 40 is not actuated. Pump clutch 28 remains
engaged because the RELS fluid chamber is not required to be
pressurized to engage pump clutch 28. Also, with power off, even
though actuators 42, 44 are not actuated, logic valves X and Y are
able to assume or maintain the same position as in the normal sixth
ratio (FIG. 11) because control pressure is provided to passage 216
due to continued activation of trim system PCS2. The control
pressure acts upon a differential area of land 290 to maintain the
position of logic valve Y (relative to the normal sixth range).
However, in comparison to the third ratio limp home configuration
of FIG. 15, control pressure is not applied to valve head 250 of
logic valve X, because the main pressure applied to spring chamber
330 maintains the spring set position of logic valve X (relative to
the normal sixth range).
[0119] Table 2 shows the status of components of control 16 during
single and double range shifts, respectively. Table 2 also
indicates the applied shift mechanisms and the status of the torque
converter clutch 26 during single range shifts. The asterisk is
used to denote that what is shown is a typical configuration; the
torque converter clutch can be engaged in any range.
TABLE-US-00002 TABLE 2 SINGLE RANGE SHIFTS Trim Logic Trimming
Torque Converter Shift Mechanism(s) System(s) Valve(s) Pressure
Clutch Range Shift Applied Actuated Actuated Switche(s) Status*
Neutral C5 PCS2 X PS1 Released Reverse Neutral C5 PCS2 X PS3
Released 1.sup.st Neutral C5 PCS2 X PS4 Released 2.sup.nd 1.sup.st
2.sup.nd C5 PCS2 X, Y PS3, PS4 Released 2.sup.nd 3.sup.rd C5 PCS2
X, Y PS1, PS4 Released 3.sup.rd 4.sup.th C1 PCS1 X, Y PS2, PS4
Applied 4.sup.th 5.sup.th C1 PCS1 Y PS3, PS4 Applied 5.sup.th
6.sup.th C1 PCS1 Y PS2, PS3 Applied 6.sup.th 7.sup.th C2 PCS2 Y
PS1, PS3 Applied 7.sup.th 8.sup.th C2 PCS2 Y PS3, PS4 Applied
[0120] Control 16 accomplishes single range shifts by selectively
actuating and deactuating the appropriate trim systems and pressure
switches, pursuant to Table 2 and in a similar manner as described
above. For example, during a shift from reverse to neutral, PCS1
and logic valve X are deactivated to release shift mechanism C2.
During a shift from third forward ratio to fourth forward ratio,
PCS2 is deactivated to release shift mechanism C5 and PCS4 is
activated to apply shift mechanism C4. During a shift from second
forward ratio to third forward ratio, PCS4 is deactivated to
release shift mechanism C4 and PCS1 is actuated to apply shift
mechanism C1. In addition, the TCC subsystem is actuated to engage
the torque converter clutch. During a shift from third forward
ratio to fourth forward ratio, PCS2 is deactivated to release shift
mechanism C5 and PCS4 is activated to apply shift mechanism C4. In
the illustrated embodiment, the other single range shifts operate
in a like manner according to the values listed in Table 2.
[0121] Because of the multiplexed configuration of the trim
systems, only the PCS1 and PCS2 trim systems are ever implicated in
any of the single range shifts, as shown by Table 2.
[0122] Table 3 shows the status of components of control 16 during
double range shifts, or skip shifts. Table 3 also indicates the
applied shift mechanisms and the status of the torque converter
clutch during the skip shifts. The asterisk is used to denote that
what is shown is a typical configuration; the torque converter
clutch can be engaged in any range.
TABLE-US-00003 TABLE 3 DOUBLE RANGE (SKIP) SHIFTS Actuated Trimming
Torque Converter Applied Shift Actuated Logic Pressure Clutch Range
Shift Mechanism Trim System Valve(s) Switche(s) Status* Reverse C5
PCS2 X PS1, PS3 Released 1.sup.st Reverse C5 PCS2 X PS1, PS4
Released 2.sup.nd 1.sup.st 3.sup.rd C5 PCS2 X, Y PS1, PS3 Released
2.sup.nd 4.sup.th C4 PCS4 X, Y PS1, PS2 Released 3.sup.rd 5.sup.th
C1 PCS1 X, Y PS2, PS3 Released 4.sup.th 6.sup.th C1 PCS1 Y PS2, PS4
Applied 5.sup.th 7.sup.th C3 PCS3 Y PS1, PS2 Applied 6.sup.th
8.sup.th C2 PCS2 Y PS1, PS4 Applied
[0123] Control 16 accomplishes double range shifts or skip shifts
by selectively actuating and deactuating the appropriate trim
systems and pressure switches, pursuant to Table 3 and in a similar
manner as described above. For example, because of the multiplexed
arrangement of the trim systems, trim system PCS2 is implicated in
the skip shifts from reverse to first, reverse to second, first to
third, and sixth to eighth forward ratio; and trim system PCS1 is
implicated in the skip shifts from third to fifth and fourth to
sixth forward ratio.
[0124] Other charts showing additional details of the single and
double range shifts are provided in Long et al., U.S. Provisional
Patent Application Ser. No. 61/045,141, filed Apr. 15, 2008, which
is incorporated herein by this reference.
[0125] The present disclosure describes patentable subject matter
with reference to certain illustrative embodiments. The drawings
are provided to facilitate understanding of the disclosure, and may
depict a limited number of elements for ease of explanation. Except
as may be otherwise noted in this disclosure, no limits on the
scope of patentable subject matter are intended to be implied by
the drawings. Variations, alternatives, and modifications to the
illustrated embodiments may be included in the scope of protection
available for the patentable subject matter.
* * * * *