U.S. patent application number 13/567561 was filed with the patent office on 2012-11-22 for automatic work brake.
This patent application is currently assigned to BENDIX COMMERCIAL VEHICLE SYSTEMS LLC. Invention is credited to Mark A. Bennett, Richard J. Conklin, Timothy J. Frashure, Kenneth A. Grolle, David W. Howell, Matthew E. Rogers, Ron R. Stahl, Michael D. Tober.
Application Number | 20120296543 13/567561 |
Document ID | / |
Family ID | 38294108 |
Filed Date | 2012-11-22 |
United States Patent
Application |
20120296543 |
Kind Code |
A1 |
Rogers; Matthew E. ; et
al. |
November 22, 2012 |
AUTOMATIC WORK BRAKE
Abstract
A vehicle, air brake system is presented with an improved
service work brake arrangement. The arrangement may provide a
service work brake function or both a service work brake function
and a parking brake function for the vehicle. The arrangement may
provide an improved service work brake arrangement disposed within
a housing for reducing the number of components and plumbing
required to achieve this functionality versus prior known systems.
The arrangement may utilizes a pneumatic latching valve to deliver
pressurized air for applying a vehicle's service brakes. The
pneumatic latching valve opens upon receiving a pneumatic control
signal from an electronically controlled valve and closes upon
receiving a pneumatic control signal from another source. In
addition, a controller and control logic may be provided for
controlling the arrangement.
Inventors: |
Rogers; Matthew E.; (Elyria,
OH) ; Bennett; Mark A.; (Lagrange, OH) ;
Stahl; Ron R.; (Medina, OH) ; Tober; Michael D.;
(Bay Village, OH) ; Grolle; Kenneth A.; (Elyria,
OH) ; Conklin; Richard J.; (Bay Village, OH) ;
Frashure; Timothy J.; (Columbia Station, OH) ;
Howell; David W.; (Oak Ridge, NC) |
Assignee: |
BENDIX COMMERCIAL VEHICLE SYSTEMS
LLC
Elyria
OH
|
Family ID: |
38294108 |
Appl. No.: |
13/567561 |
Filed: |
August 6, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12709891 |
Feb 22, 2010 |
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13567561 |
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11433249 |
May 12, 2006 |
7690735 |
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12709891 |
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Current U.S.
Class: |
701/70 |
Current CPC
Class: |
B60T 13/662 20130101;
Y10T 137/87096 20150401 |
Class at
Publication: |
701/70 |
International
Class: |
B60T 7/12 20060101
B60T007/12 |
Claims
1. A controller for an automatic work brake on a vehicle, the
controller comprising: at least one input receiving at least one
input signal indicative of a status of the vehicle representing a
speed of the vehicle and a service brake pedal position; a
processor determining, based on the input signal, whether to
automatically apply the automatic work brake; and an output
delivering a control signal for automatically engaging the work
brake based on the determination of the processor.
2. The controller for an automatic work brake on a vehicle as set
forth in claim 1, wherein: the at least one input signal indicative
of a status of the vehicle represents at least one of a driver
present, a fault status of a vehicle system, a rotational speed of
an engine of the vehicle, a throttle demand of the engine of the
vehicle, a transmission gear engaged, a voltage of the vehicle, and
a supply pressure of a vehicle brake system.
3. The controller for an automatic work brake on a vehicle as set
forth in claim 1, wherein: the processor determines if the vehicle
is in one of a SAFE status and an UNSAFE status based on the at
least one input signal.
4. The controller for an automatic work brake on a vehicle as set
forth in claim 3, wherein: the processor determines the vehicle is
in the SAFE status if the speed of the vehicle is less than a
predetermined speed and the service brake pedal is depressed.
5. The controller for an automatic work brake on a vehicle as set
forth in claim 4, wherein: if the processor determines the vehicle
is in the SAFE status, the processor determining to automatically
apply the work brake.
6. The controller for an automatic work brake on a vehicle as set
forth in claim 4, wherein: if the processor determines the vehicle
is in the SAFE status, the processor determining to automatically
release the work brake if a throttle demand of the engine is above
a predetermined level.
7. The controller for an automatic work brake on a vehicle as set
forth in claim 3, wherein: if the work brake is applied, the
processor determines the vehicle is in the UNSAFE status if a fault
status of the vehicle system is faulted; and if the processor
determines the vehicle is in the UNSAFE status, the processor
enforcing a failsafe function.
8. The controller for an automatic work brake on a vehicle as set
forth in claim 1, wherein: if the processor determines to
automatically apply the work brake, the output delivers a control
signal for activating a valve to engage the work brake.
9. A system for automatically applying a work brake, the system
comprising: a first valve controlling pressure delivered to a
service brake; a controller, including: at least one input signal
indicative of a status of the vehicle representing a speed of the
vehicle and a service brake pedal position; a processor
determining, based on the input signal, whether to automatically
apply the automatic work brake; and an output delivering a control
signal to the first valve, for automatically engaging the service
brake as the work brake, based on the determination of the
processor.
10. The system for automatically applying as work brake as set
forth in claim 9, the system further including: a second valve
including an outlet fluidly communicating with the service
brake.
11. The system for automatically applying a work brake as set forth
in claim 10, wherein: the controller delivers an electronic control
signal to the first valve; and the first valve delivers a pneumatic
open control signal to the second valve.
12. The system for automatically applying a work brake as set forth
in claim 11, wherein: the second valve is set to an open state for
delivering fluid pressure to the service brake upon receiving the
pneumatic open control signal from the first valve.
13. The system for automatically applying a work brake as set forth
in claim 12, wherein: the second valve latches in the open state
and remains in the open state even after the pneumatic open control
signal from the first valve ceases; and the service brake acts as
the work brake While the second valve is latched in the open
state.
14. The system for automatically applying a work brake as set forth
in claim 12, wherein: the second valve is set to a closed state for
not delivering fluid pressure to the service brake upon receiving a
pneumatic close control signal from as fourth valve; the second
valve latches in the closed state and remains in the closed state
even after the pneumatic close control signal ceases.
15. The system for automatically applying a work brake as set forth
in claim 14, wherein: the outlet of the fourth valve fluidly
communicates with a closing control port of the second valve.
16. The system for automatically applying a work brake as set forth
in claim 14, wherein: the control signal delivered by the
controller to the first valve is a first electronic control signal;
the controller also delivers a second electronic control signal the
fourth valve based on the determination of the processor; and the
respective electronic control signals delivered to the first valve
and the fourth valve, based on the determination of the processor,
control the first valve and the fourth valve for automatically
engaging and releasing the service brake as the work brake.
17. The system for automatically applying a work brake as set forth
in claim 6, wherein: the processor determines to automatically
engage the service brake as the work brake if the service brake
pedal is in a depressed position and the speed of the vehicle is
less than a predetermined speed.
18. The system for automatically applying a work brake as set forth
in claim 17, wherein: the processor determines to automatically
release the work brake if a throttle demand of the engine is above
a predetermined level.
19. The system for automatically applying a work brake as set forth
in claim 16, wherein: if the processor determines to automatically
apply the service brake as the work brake, the controller delivers
the first electronic control signal to the first valve for setting
the first valve to an open state; while in the open state, the
first valve delivers a pneumatic control signal to the opening
control port of the second valve for setting the second valve to an
open state; and while in the open state, the outlet of the second
valve fluidly communicates with the inlet of the second valve so
that pressure from the inlet of the second valve is fluidly
communicated to the service brake for actuating the service
brake.
20. The system for automatically applying, a work brake as set
forth in claim 19, wherein: if the processor determines to
automatically release the service brake as the work brake, the
controller ensures the first electronic control signal is no longer
delivered to the first valve while delivering the third electronic
control signal to the fourth valve for setting the fourth valve to
an open state; while in the open state, the fourth valve delivers a
pneumatic control signal to the closing control port of the second
valve for setting the second valve to a closed state; and while in
the closed state, the outlet of the second valve does not fluidly
communicate with the inlet of the second valve so that pressure
from the inlet of the second valve is not fluidly communicated to
the service brake so the service brake is not actuated.
21. A controller for an automatic work brake on a vehicle, the
controller comprising: at least one input receiving at least one
input signal indicative of a status of the vehicle representing a
speed of the vehicle and a service brake pedal position; a
processor determining an intent of the driver, based on the at
least one input signal, to automatically apply the automatic work
brake when the speed of the vehicle is less than a predetermined
speed and the service brake pedal is depressed; and an output
delivering a control signal for automatically engaging the work
brake based on the intent of the driver.
22. The controller for an automatic work brake on a vehicle as set
forth in claim 21, wherein: the processor determines the intent of
the driver is to automatically release the work brake if the at
least one input signal indicates a throttle demand of the engine is
greater than a predetermined level.
23. A system for automatically at least one of applying and
releasing a work brake, the system comprising: means for
determining whether to at least one of automatically apply and
release the work brake; and means for controlling pressure
delivered to a service brake, the pressure being continuously
fluidly communicated to the service brake for causing the service
brake to act as the work brake when it is determined to
automatically apply the work brake, and the pressure being not
fluidly communicated to the service brake for releasing the work
brake when it is determined to automatically release the work
brake.
24. The system for automatically at least one of applying and
releasing a work brake as set forth in claim 23, further including:
means for determining an intent of a driver; the means for
determining whether to automatically at least one of apply and
release the work brake being based on the intent of the driver.
25. A method controlling an automatic work brake on a vehicle, the
method comprising: receiving at least one input signal indicative
of a status of the vehicle representing at least one of a speed of
the vehicle and a service brake pedal position; determining to
automatically apply the automatic work brake based on the at least
one input signal; and delivering a control signal for automatically
applying the work brake based on the determination to automatically
apply the automatic work brake.
26. The method controlling an automatic work brake on a vehicle as
set forth in claim 25, further including: determining an intent of
the driver based on the at least one input signal.
27. The method controlling an automatic work brake on a vehicle as
set forth in claim 25, wherein the step of determining to
automatically apply the automatic work brake includes: determining
to automatically apply the automatic work brake when the speed of
the vehicle is less than a predetermined speed and the service
brake pedal is depressed.
28. The method controlling an automatic work brake on a vehicle as
set forth in claim 25, further including: determining to
automatically release the automatic work brake when a throttle
demand of the engine is above a predetermined level.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of prior U.S. application
Ser. No. 12/709,891, filed Feb. 22, 2010, which is a divisional of
prior U.S. application Ser. No. 11/433,249, filed May 12, 2006, now
U.S. Pat. No. 7,690,735, the entire contents of each of which is
herein fully incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] Commercial vehicles, such as for example tractor trailers,
often utilize air brake systems. A typical air brake system is
capable of performing a service brake function and a park brake
function. Service braking or normal braking refers to actuating the
vehicle's brakes by depressing a brake pedal to deliver compressed
air to a brake actuator. Service braking is used to slow the
vehicle or bring the vehicle to a stop. Once stopped, the driver
may wish to apply the park brakes to prevent the vehicle from
rolling. Typical vehicle air brake systems utilize spring brakes to
perform the park brake function. Spring brakes, as are known in the
art, utilize spring force to engage the brakes and hold the vehicle
stationary. Air pressure is used to disengage the brakes by
compressing the spring in order to allow the vehicle to move.
[0003] Some vehicle air brake systems also include a work brake
function for commercial vehicles that stop and start frequently,
such as for example waste collection vehicles. Work braking refers
to using a service brake application to perform a temporary park
brake function. In other words, utilizing compressed air to apply
the service brakes to keep the vehicle from roiling while the
vehicle is parked. Utilizing service brakes in applications with
frequent stopping and starting is preferable to utilizing park
brakes because the service brakes are more durable and use less
compressed air.
[0004] Typical work brake systems, however, are either not fail
safe or have complicated fail safe systems. A fail safe work brake
system will apply the park brakes if a particular vehicle condition
exists or a contemplated specific system failure occurs, such as
loss of compressed air. An example of a complex fail sale work
brake system can be found in U.S. Pat. No. 5,458,402.
[0005] Furthermore, electro-pneumatic brake systems for commercial
vehicles have been developed, though presently are not widely used.
Present work brake systems, including known systems with complex
pneumatic fail safe systems, have no provisions for providing fail
safe operation in case of an electrical failure or driver error
(e.g. the driver turns the ignition off while the work brake is
engaged).
SUMMARY
[0006] The present invention relates generally to vehicle air brake
systems. In particular the present invention relates to a vehicle
air brake system with an improved service work brake arrangement.
The arrangement improves the work brake system for either a
pneumatic failure or an electrical failure. Thus, the logic of the
system and method of the present invention may include both
electrical and pneumatic components. The arrangement may provide a
service work brake function or both a service work brake function
and a parking brake function for the vehicle. The arrangement may
provide an improved service work brake arrangement disposed within
a housing for reducing the number of components and plumbing
required to achieve this functionality versus prior known
systems.
[0007] Furthermore, the invention may include a controller and
control logic for controlling the arrangement. The controller and
control logic may control the work brake and park brake functions,
as well as other vehicle functions, based on data received from a
variety of input sources. Thus, the controller may enable or
disable certain vehicle functions as a function of the data
received or inferences made from the data.
[0008] In one embodiment, the arrangement utilizes a pneumatic
latching valve to deliver pressurized air for applying a vehicle's
service brakes. The pneumatic latching valve opens upon receiving a
pneumatic control signal from an electronically controlled valve
and closes upon receiving a pneumatic control signal from another
source or via spring return in absence of supply pressure. In
another embodiment, an electronic control unit is employed to
automatically engage and disengage the work brake function based on
receiving input indicative of one or more of: the status of the
vehicle, the status of the driver, the intent of the driver, and
the plausibility of the driver's intent.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The foregoing features of aspects of the present invention
will become apparent to one skilled in the art to which the present
invention relates upon consideration of the following description
of the invention with reference to the accompanying drawings, in
which:
[0010] FIG. 1 is a partial schematic representation of a prior art
air brake system for a vehicle;
[0011] FIG. 2 is a partial schematic representation of an exemplary
embodiment of an air brake system for a vehicle according to the
principles of present invention.
[0012] FIG. 3 is a schematic representation clan exemplary
embodiment of a valve arrangement of the system of FIG. 2;
[0013] FIG. 4 is a schematic representation of a valve arrangement
of a second exemplary embodiment of the air brake system according
to the principles of present invention;
[0014] FIG. 5 is a schematic representation of a valve arrangement
of a third exemplary embodiment of the airbrake system according to
the principles of present invention;
[0015] FIG. 6 is schematic representation of an exemplary
embodiment of a controller for the system of FIG. 2; and
[0016] FIG. 7 is a flow chart of an exemplary embodiment of control
logic for the controller of FIG. 6.
DETAILED DESCRIPTION
[0017] While various aspects and concepts of the invention are
described and illustrated herein as embodied in combination in the
exemplary embodiments, these various aspects and concepts may be
realized in many alternative embodiments, either individually or in
various combinations and sub-combinations thereof. Unless expressly
excluded herein all such combinations and sub-combinations are
intended to be within the scope of the present invention. Still
further, while various alternative embodiments as to the various
aspects and features of the invention, such as alternative
materials, structures, configurations, methods, devices, software,
hardware, control logic and so on may be described herein, such
descriptions are not intended to be a complete or exhaustive list
of available alternative embodiments, whether presently known or
identified herein as conventional or standard or later developed.
Those skilled in the art may readily adopt one or more of the
aspects, concepts or features of the invention into additional
embodiments within the scope of the present invention even if such
embodiments are not expressly disclosed herein. Additionally, even
though some features, concepts or aspects of the invention may be
described herein as being a preferred arrangement or method, such
description is not intended to suggest that such feature is
required or necessary unless expressly so stated. Still further,
exemplary or representative values and ranges may be included to
assist in understanding the present invention however, such values
and ranges are not to be construed in a limiting sense and are
intended to be critical values or ranges only if so expressly
stated.
[0018] To distinguish the characteristics of the present invention
from a current state of the art air brake system. FIG. 1 provides a
partial schematic representation of a prior art air brake system
100. The prior art brake system 100 includes a primary air
reservoir 112 (typically for supplying a rear or trailer brake
circuit) and secondary air reservoir 114 (typically for supplying a
front or tractor brake circuit). The primary and secondary air
reservoirs 112, 114 supply pressurized air to apply a set of front
service brake assemblies 116a and rear service brake assemblies
116b, and for releasing a set of spring brake assemblies 118. A set
of air lines 119 communicate the pressurized air from the
reservoirs 112, 114 to the brake assemblies 116a, 116b, and
118.
[0019] Service brakes generally refer to the brake assembly located
on the axles of a commercial vehicle, which are actuated via the
application of pressurized air, as is known in the art. The spring
brakes generally refer to the brake assembly located on the axles
that utilizes a spring to apply the vehicle's parking brakes. Air
pressure is used to keep the spring compressed and the parking
brakes released, as is known in the art.
[0020] The air brake system 100 may also include a brake valve 120
and a parking control valve 122. The brake valve 120 includes a
foot pedal 124, which opens the valve when the pedal is depressed.
When open, the brake valve 120 allows pressurized air to flow from
the reservoirs 112, 114 to a relay valve 126 for actuating the
service brakes, as is known in the art. The parking control valve
122, which may be opened manually, allows pressurized air to flow
from reservoirs 112, 114 to a relay valve 128 for releasing the
parking brakes, as is known in the art. A typical prior art air
brake system may also include a variety of additional valves and
components, as is known in the art. For example, tractor protection
valves, quick release valves, spring brake valves, etc. are often
employed. These valves and components are known in the art and are
omitted from the discussion and illustration of the prior art and
exemplary embodiments of the present invention for simplicity. The
brake system according to the present invention, however, may
utilize these and other valves and components.
[0021] FIG. 2 illustrates an exemplary embodiment of a pneumatic
brake system 150 according to the present invention. Similar to the
prior art pneumatic brake system 100 of FIG. 1, the pneumatic brake
system embodiment in FIG. 2 may include a primary air reservoir 152
and secondary air reservoir 154 to supply pressurized air for
applying a set of front service brake assemblies 156a and rear
service brake assemblies 156b, and for releasing a set of spring
brake assemblies 158. In the context of this invention, control or
pilot air generally refers to a pneumatic signal for opening or
closing a pneumatically actuated valve, while supply or delivery
air generally refers to the pressurized air routed by valves and
used to apply or release a terminal device, such as a spring brake
or service brake.
[0022] The air brake system 150 may also include a brake valve 160
having a foot pedal 164, which opens the valve when the pedal is
depressed. The brake valve 160 communicates with the primary air
reservoir 152 and the secondary air reservoir 154 via air lines 166
and 168, respectively. When open, the brake valve 120 allows
pressurized air to flow from reservoirs 152, 154 to the service
brake assemblies 156a, 156b via air lines 170 and to the rear
service brake assemblies 156b via air lines 172 and 174 for
actuating the service brakes. A relay valve 176 (FIG. 2) may be
installed between the rear service brake assemblies 156b and the
brake valve 160 such that the air from the brake valve acts as
control air for the relay valve, as is known in the art. The air
lines 172 and 174 communicate with a two-way check valve 178
mounted to the control port of the relay valve 176. Thus, air from
the reservoir with the higher air pressure exits the check valve to
apply the rear service brakes 156b.
[0023] The pneumatic brake system 150 in FIG. 2 replaces the park
control valve 122 of the prior art system 100 of FIG. 1 with a
valve arrangement 200 that may perform the work brake control, park
brake control, or both parking brake and service work brake
control.
[0024] FIG. 3 is a schematic representation of an exemplary
embodiment of a valve arrangement 200 according to the present
invention. For ease of explanation, the valve arrangement 200 may
be described in two sections: a service work brake section 202 and
a park brake section 204. The service work brake section 202
includes a first valve 206 and a second valve 208 within a housing
209. The housing 209 may allow the first valve 206 and the second
valve 208, or the functionality of the first and second valve, to
be consolidated within single unit, thus reducing the number of
components and plumbing within the pneumatic brake system 150.
[0025] The first valve 206 is adapted to open in response to an
electronic signal and close when the electronic signal is
discontinued. For example, the first valve 206 may be an electric
control valve or a solenoid valve. In the exemplary embodiment of
FIG. 3, the first valve 206 is a three-way, two-position, normally
closed to delivery, normally open to exhaust, solenoid valve.
However, other electrically controllable valves or pneumatic valves
may be used, including, but not limited to, piezoelectric valves
and micro machine valves.
[0026] The first valve 206 includes a pneumatic inlet 210, a
pneumatic outlet 212, and an exhaust port 214. The two operational
positions or modes of the electric control valve 206, are null or
closed, and energized, delivery or open. When energized, the first
valve 206 allows air flow through the valve from the inlet 210 to
the outlet 212. When closed, the first valve 206 closes the path
from the inlet 210 to the outlet 212, but opens the path from the
outlet 212 to the exhaust port 214. Thus, when the first valve 206
is closed, any delivery air immediately downstream from the first
valve may vent out of the exhaust port 214.
[0027] The second valve 208 is adapted to open in response to a
first pneumatic signal and remain open when or if the first signal
is discontinued. Further, the second valve 208 may be adapted to
close in response to receiving a second pneumatic signal and remain
closed when or if the second signal is discontinued. Thus, the
second valve 208 may be a pneumatic latching valve. In the
exemplary embodiment of FIG. 3, the second valve 208 is a
three-way, two position, normally closed to delivery, normally open
to exhaust, air-piloted latching valve with an automatic return to
close feature, such as for example a spring return. Other valve
types, styles, or models, however, may be employed. The automatic
return to close capability of the second valve 208 will
automatically move the valve from the delivery position to the
closed position as supply pressure at an inlet 220 is reduced to a
predetermined minimum. This capability greatly reduces the chance
of the vehicle rolling between the time that air pressure is
declining and the time that the park brakes are applied
autonomously (i.e. pneumatically fail safe). The minimum can be
influenced by selection of the spring installed, for example. An
example of a suitable valve is a Bendix PP-5 Push-Pull Type Control
Valve, adapted to be air-piloted. Other valve variants may also be
used for second valve 208.
[0028] The second valve 208 includes an inlet 220, an outlet 222, a
first control signal port 224, a second control signal port 226,
and an exhaust port 228. The second valve 208 possesses the same
two operational positions or modes as the first valve 206, although
the input signal for the second valve 208 is pneumatic pressure,
not electric current. When open, the second valve 208 allows air to
flow through the valve from the inlet 220 to the outlet 222. When
closed, the second valve 208 closes the path from the inlet 220 to
the outlet 220, but opens a path from the outlet to the exhaust
port 228. Thus, when the second valve 208 is closed, any delivery
air immediately downstream from the second valve may vent out of
the exhaust port 228.
[0029] The first valve 206 is in circuit communication with a
device capable of sending or relaying an electronic signal. The
device may be, for example, a manual, pneumatic, or electrical
switch unit 229 and/or a controller or electronic processing unit
230 (shown in FIG. 2 and 6 and discussed in detail below). The
brake system 150 includes a source of pressurized control air not
shown) and a source of pressurized supply air (not shown). The
primary air reservoir 152 and secondary air reservoir 154 may serve
as the sources for the control and supply air, or separate sources
may be provided. The source of pressurized control air and the
source of pressurized supply air may be a single source or may be
separate sources of pressurized air. In the exemplary embodiment of
the valve arrangement 200, the source of pressurized signal air and
the source of pressurized supply air are the same source. In
particular, a pneumatic line 231 from the primary air reservoir 112
and a pneumatic line 232 from the secondary air reservoir 114
connect to a double check valve 234. Thus, air from the reservoir
with the higher air pressure will flow through the double check
valve to supply the pressurized control air and supply air to the
valve arrangement 200.
[0030] The inlet 210 of the first valve 206 and the inlet 220 of
the second valve 208 communicate with the pressurized air exiting
the double check valve 234 via pneumatic lines 236. The first
pneumatic control signal port 224 of the second valve 208
communicates with the pneumatic outlet 212 of the first valve 206
via a pneumatic line 236. The outlet 222 of the second valve 208
communicates with the rear service brake assemblies 156b via a
pneumatic line 240. As shown in FIG. 2, the pneumatic line 240 may
connect to an additional double check valve 241 which communicates
with the control port of the relay valve 176 to access the service
brake system. Thus, the pneumatic signal from the second valve 208
via the pneumatic line 240 can function as a supply signal to
actuate a terminal device such as the service brakes 156b or may
function as a control signal to control another device, such as for
example the relay valve 176 or a brake valve actuator, that results
in application of the service brakes. Furthermore, in the
embodiment of FIG. 2, the pneumatic signal from the second valve
208 controls only the rear service brakes 156b. The brake system
150, however, could also be configured to allow the pneumatic
signal to operate the front service brakes 156a.
[0031] An optional pressure regulating or reducing device 242, such
as for example, a pressure regulator, may be included in the work
brake section 202 to restrict the amount of air pressure being
delivered through the second valve 208 when open from exceeding a
predetermined amount. For example, the full pressure available from
the source of pressurized supply air may be 100 psi. The pressure
regulating device 242 may reduce the pressure actually delivered
to
[0032] The second control signal port 226 of the second valve 208
communicates with a source of a pneumatic signal (described further
below). Thus, while the first valve 206 supplies a pneumatic signal
to the second valve 208 to open the second valve, a second
pneumatic signal from a second source may be utilized to close the
second valve 208. The source of the second pneumatic signal may be
any source capable of sending a pneumatic signal to actuate the
second valve 208, such as for example, an electronically or
pneumatically actuated valve adapted to deliver a pneumatic
signal.
[0033] The park brake section 204 of the valve arrangement 200
includes a third valve 250, a fourth valve 252, and a fifth valve
254 within a second housing 255. Thus, as with the first housing
209, the second housing 255 may allow the third valve 250, the
fourth valve 252, and the fifth valve 254, or the functionality of
the valves, to be consolidated within single unit to, reduce the
number of components and plumbing within the pneumatic brake system
150. The first housing 209 and the second housing 255 may form a
single common housing for both the service work brake section 202
and the park brake section 204. The first housing 209 and the
second housing 255, however, may be separate housings forming
separate assemblies. The separate assemblies, however, may be
connected in a fixed manner, for example by one or more fittings,
such that the first and second housing 209, 255 form a single
assembly.
[0034] The third and fourth valves 250, 252 are substantially
similar to the first valve 206 of the service work brake section
202 and the fifth valve 254 is substantially similar to the second
valve 208 of the service work brake section 202. Thus, the third
valve 250 includes a pneumatic inlet 256, a pneumatic outlet 258,
and an exhaust port 260 and the fourth valve 252 includes a
pneumatic inlet 262, a pneumatic outlet 264, and an exhaust port
266. Further, the fifth valve 254 includes an inlet 268, an outlet
270, a first control signal port 272, a second control signal port
274, and an exhaust port 276. The valves of the park brake section
204 possess the same two operational positions or modes as the
valves of the service work brake section 202.
[0035] The third and fourth valves 250, 252 are in circuit
communication with a device capable of sending or relaying an
electronic signal. For example, the device may include a manual,
pneumatic, or electrical switch unit, a controller or an electronic
processing unit, such as for example the switch unit 229 and the
processing unit 230 of FIG. 2.
[0036] The pneumatic inlet 256 of the third valve 250, the
pneumatic inlet 262 of the fourth valve 252 and the inlet 268 of
the fifth valve 254 communicate with pressurized air from the
double check valve 234 via the pneumatic lines 236. For the third
and fourth valves 250, 252, this air represents control air and for
the fifth valve 254, this air represents supply air.
[0037] The first control signal port 272 of the fifth valve 254
communicates with the pneumatic outlet 264 of the fourth valve 252
via a pneumatic line 278. The second control signal port 274 of the
fifth valve 254 communicates with the pneumatic outlet 258 of the
third valve 250 via a pneumatic line 280. The outlet 270 of the
fifth valve 254 communicates with spring brake assemblies 158 via a
pneumatic line 282. A relay valve 283 may be installed between the
spring brake assemblies 158 and the fifth valve 254 such that air
from the parking brake section 204 acts as control air for the
relay valve 283. Furthermore, the second control signal port 226 of
the second valve 208 communicates with the outlet 264 of the fourth
valve 252 via a pneumatic line 284.
[0038] The operation of the valve arrangement 200 can best be
described in relations to the operation of a commercial vehicle,
such as for example, a tractor trailer. In an initial state, the
vehicle is parked with the parking brakes applied and the service
work brakes not applied. The first, third, and fourth valves 206,
250, 252 are not energized, and the second and fifth valves 208,
254 are closed, such that pressurized supply air is not supplied to
either the spring brake assembly 158 or the service brake assembly
156b.
[0039] To unpark the vehicle, the fourth valve 252 is energized,
which supplies pressurized air in the form of a first pneumatic
control signal to the first control signal port 272 of the fifth
valve 254, and a second pneumatic control signal to the second
control signal port 226 of the second valve 208. As a result, if
the supply air pressure is greater than a predetermined amount, the
fifth valve 254 opens allowing pressurized supply air to flow
through the fifth valve to the spring brake assembly 22, releasing
the spring applied parking brakes.
[0040] At the same time, the second pneumatic control signal
received by the second valve 208 closes the second valve and opens
the valve's exhaust port 226. As a result, any air in the pneumatic
line 240 vents to atmosphere. Air would be present in the pneumatic
line 240 if the service work brakes were applied. Thus, the act of
releasing the parking brakes automatically releases the service
work brakes, if applied. Because the second valve 208 and the fifth
valve 254 latch into position, the first, third, and fourth valves
206, 250, 252 can be de-energized without impacting the position of
either latching valve 208, 254. The vehicle is now in a unparked
mode. Thus, because the first, third, and fourth valves 206, 250,
252 can be de-energized yet the vehicle may still be rolling with
the parking brakes released, loss of electrical power or an
electrical connection does not impact the status of the park
brakes.
[0041] While in the rollable, unparked mode, the driver may desire
to stop the vehicle and apply the service work brakes. To do so,
the driver stops the vehicle by a normal service brake application.
In this position, the fifth valve 254 is stilled latched in the
open or delivering position, which keeps the park brakes released.
The third valve 250 and the fourth valve 252 may be de-energized,
which allows any air in pneumatic lines 278 and 280 to be
relieved.
[0042] Once stopped, to hold the vehicle still, the driver may
engage the service work brakes by energizing the first valve 206.
As a result, the first valve 206 allows pressurized air to flow
through the first valve to the first pneumatic control signal port
224 of the second valve 208 via the pneumatic line 238. The first
pneumatic control signal to the second valve 208 opens the valve
allowing pressurized, air to flow through the second valve to the
service brake assembly 156b via air line 240, thus applying the
brakes in a service work brake application.
[0043] Because the second valve 208 latches into the open position,
the driver may de-energize the first valve 206 without affecting
the application of the service work brakes. Thus, if an electrical
failure occurred while the service work brakes were applied, the
service work brakes would remain applied despite the electrical
failure. The second valve 208 does not change position as a result
of discontinuing the electronic signal to the first valve 206.
[0044] Any of the air lines, such as air line 240, may be routed
redundantly (i.e. two or more lines) if desired. Furthermore, the
second valve 208 and the fifth valve 254 can be optionally equipped
with status sensor. Thus, in the event of a failure air line 240,
the vehicle can be parked autonomously or manually by energizing
the third valve 250.
[0045] To transition from a mode where the service work brakes are
applied to the rollable, unparked mode, the driver would follow the
same steps used to unpark the vehicle, as described above. In
particular, the driver would energize the fourth valve 252 as if
desiring to remove the park brakes. Even if the park brakes are not
applied, the act of energizing the fourth valve 252 releases both
the park brakes (if applied) and the service work brakes (if
applied).
[0046] When the vehicle has been stopped, the driver may wish to
apply the park brakes to hold the vehicle still, as opposed to
applying the service work brakes. To do so, the driver opens or
energizes the third valve 250. Opening the third valve 250 allows
pressurized air to flow through the third valve to the second
pneumatic control signal port 274 of the fifth valve 254 via the
pneumatic line 280. The second pneumatic control signal closes the
fifth valve 254, which discontinues the pneumatic supply signal
from the fifth valve to the spring brake assembly 158, thus
applying the spring brakes. In addition, closing the fifth valve
254 opens the exhaust port 276 allowing pressurized air in the
pneumatic line 282 to vent to atmosphere.
[0047] FIG. 4 is a second exemplary embodiment of the valve
arrangement 300 according to the present invention. The valve
arrangement 300 of FIG. 4 is substantially similar to the valve
arrangement 200 of FIG. 3 in that it includes a service work brake
section 302 within a first housing 303 and a park brake section 304
within a second housing 305. The valve arrangement 300 also
includes a first valve 306, a second valve 308, a third valve 310,
a fourth valve 312, and a fifth valve 314, which communicate with a
source of pressurized control air and a source of pressurized
supply air as described according to the valve arrangement 200 of
FIG. 3. A pressure reducing device 315 may be included in the valve
arrangement 400 to reduce the pressure delivered to the service
brakes 156b.
[0048] The valve arrangement 300 of FIG. 4, however, modifies the
source of a second pneumatic control signal for the second valve
308 (i.e. the pneumatic signal for closing the second valve). In
the valve arrangement 200 of FIG. 3, the fourth valve 252 delivers
the second pneumatic control signal to the second valve 208. Thus,
the pneumatic control signal that opens the fifth valve 254 also
closes the second valve 208. In the valve arrangement 300 of FIG.
4, the pneumatic control signal to close the second valve 308 is
the pneumatic supply signal from the fifth valve 314. Therefore,
when the fifth valve 314 is open, it sends a pneumatic signal to
the spring brake assembly to release the spring brakes while at the
same time sending a pneumatic control signal to the second valve
308 to close the valve, thus releasing the service work brakes, if
applied.
[0049] FIG. 5 is a third exemplary embodiment of a valve
arrangement 400 according to the present invention. The valve
arrangement 400 of FIG. 5 includes a service work brake section 402
within a housing 403 that is substantially similar to the service
work brake section 202 of the embodiment of FIG. 3. In particular,
the service work brake section 402 includes a first valve 404
adapted to open in response to an electronic signal and close when
the electronic signal is discontinued. When open, the first valve
404 delivers a pneumatic signal via an air line 406.
[0050] The service work brake section 402 also includes a second
valve 408, which is adapted to open in response to first pneumatic
signal and remain open when or if the first signal is discontinued.
Further, the second valve 408 is adapted to close in response to
receiving a second pneumatic signal and remain closed when or if
the second signal is discontinued. When open, the second valve 408
delivers a pneumatic supply signal to a service work brake assembly
156b via an air line 410. A pressure regulating device 411 may be
included in the valve arrangement 400 to reduce the pressure
delivered to the
[0051] The valve arrangement 400 of FIG. 5, however, illustrates
how the service work brake section 402 may integrate with a purely
pneumatic park control valve 412, such as for example, the park
control valve 122 of the prior art brake system of FIG. 1. The
parking control valve 412 may be a push-pull, manually operable
on/off valve with an integral double check valve, however, other
variants are possible. An example of a suitable park control valve
is PP-DC Park Control Valve available from Bendix Commercial
Vehicle Systems, LLC.
[0052] The parking control valve 412 communicates with the primary
air reservoir 112 and the secondary air reservoir 114 (see FIG. 2)
via air lines 414 and 416, respectively. When the parking control
valve is open, the valve delivers pressurized air from either the
primary reservoir 112 or secondary reservoir 114, whichever is
higher pressure.
[0053] When open, the parking control valve 412 delivers a
pneumatic supply signal to the spring brake assemblies 158 via an
air line 418 to release the park brakes. The park control valve 412
may also communicate with the second valve 408 via air line 420 to
supply a pneumatic supply signal to close the second valve 408,
similar to the arrangement of FIG. 4.
[0054] Referring to FIG. 6, the controller 230, as discussed
previously, may be capable of sending or relaying an electronic
signal to the valve arrangement 200 for engaging and/or disengaging
the work brake function and/or parking brake functions. The
controller 230 may be, for example a vehicle electronic control
unit (ECU), such as an antilock brake ECU, in communication with a
voltage source 428 for supplying power to the controller. The
controller 230, however, can be a wide variety of control devices,
such as for example, a controller integral to a valve.
[0055] In an exemplary embodiment, the controller 230 may include
one or more inputs 429 for receiving input data or signals
indicative of the status or condition of the vehicle and/or
operator from one or more input sources 430. The one or more input
sources 430 may include a wide variety of input devices. For
example, a first manual switch 432 may be provided to send a signal
to the controller 230 to engage and/or disengage the park brakes on
the tractor and trailer and a second manual switch 434 may be
provided to send a signal to the controller to engage and/or
disengage the work brakes. Furthermore, one or more sensors and/or
switches 436 may be provided capable of sending signals to the
controller 230 indicative of, for example, an operating condition
or status of the vehicle, the status, intent, or request of the
driver/operator, vehicle diagnostic information, or any other
relevant information.
[0056] Based on the input signals, the controller 230 may include
one or more outputs 437 for automatically delivering control
signals to the valve arrangement 200 and/or one or more other
output devices 438. The one or more output devices 438 may include
for example, but not be limited to, devices capable or actuating or
controlling an engine throttle, a vehicle transmission, a speed
governor, and status enunciators (indicator lights, displays,
audible devices, etc).
[0057] The controller 230 may include control logic, which may be
stored in memory 440, and a processor for applying the logic 442.
The memory 440 may or may not be integral to the controller 230.
The controller 230 may implement the control logic to analyze the
information from the input devices 430 in order to determine a
proper course for action, which may include intervening in the
operation of the vehicle to automatically enable, disable, or
control a vehicle system or device.
[0058] FIG. 7 presents a flowchart of an exemplary embodiment of
the logic of the controller 230. The logic may include the steps of
inferring the status of the vehicle 450, inferring the status of
the driver or operator 452, enabling appropriate vehicle functions
454, interring the driver/operator intent 456, checking the
plausibility of the driver/operator intent 458, activating the
driver-intended function 460, enforcing a failsafe function 462,
and enunciating the status 464. The logic may be configured to
continually repeat the steps while the controller/vehicle is
powered on.
[0059] In the step of intoning the status of the vehicle 450, the
controller 230 may receive data from the one or more input sources
430, and based on the data received, the controller may determine
whether the vehicle is in a SAFE or UNSAFE status. The data from
the one or more input sources 430 may include, but not be limited
to, vehicle speed, engine rotational speed, transmission gear
engaged, vehicle voltage, and air brake system supply pressure
(park brake circuit air pressure and service brake circuit air
pressure). One of ordinary skill in the art will appreciate that
the controller 230 may utilize a wide variety of data configured in
a wide variety of ways. For example, the controller 230 may receive
an indication of vehicle speed directly from a vehicle speed sensor
or may infer/determine vehicle speed from data indicative of engine
rotational speed and throttle position.
[0060] A SAFE status and an UNSAFE status may depend on a variety
of factors, such as user preference, vehicle configuration, vehicle
options, and the specific embodiment of the present invention being
employed. These factors may be predetermined and stored in memory
440 or may be inferred from input data received.
[0061] A SAFE vehicle status may include, but not be limited to, a
determination that one or more vehicle systems are diagnostically
sound (e.g. air pressure and electrical integrity of an air brake
system are sufficient), the vehicle being stopped or moving very
slowly, and the auxiliary and/or Power-Take-Off functions being
turned off or properly stowed. Thus, an UNSAFE vehicle status may
include, but not be limited to, one or more systems or components
being diagnosed as faulty, the vehicle being in motion, and the
auxiliary and/or Power-Take-Off functions (e.g. a refuse compactor,
passenger doors, etc.), not being disabled or properly stowed. One
of ordinary skill in the art will appreciate that the combination
of input data indicative of a SAFE or UNSAFE status may be
predetermined at the user's discretion and stored in memory to be
referenced by the controller 230 to make the status
determination.
[0062] If the vehicle status is determined to be UNSAFE, the
controller 230 may enforce a failsafe function 462. Failsafe
functions may include any action taken by the controller 230 to
alter the vehicle status from a state determined to be unsafe or
inappropriate to a state determined by the controller to be safer
or more appropriate. For example, the controller 230 may prohibit
an unsafe stationary vehicle from moving, may automatically brake a
vehicle rolling away without a driver present, may place the
vehicle into a Limp-To-Roadside mode by allowing timed durations of
low-speed maneuvers to move the vehicle from an unsafe or undesired
location, may prohibit brake drag that could lead to risk of fire,
may enunciate the unsafe condition while the vehicle is moving, and
may disable one or more functions when stopped. Other failsafe
functions, however, are possible and may be implemented by the
controller 230.
[0063] The failsafe functions may be effectuated in a variety of
ways. Some possible actions by the controller 230 in order enforce
a failsafe function include, but are not limited to, automatically
applying the park brakes, prohibiting, manual release of the park
brakes, automatically applying the work brake, automatically
releasing the work brake, prohibiting engagement of a non-neutral
transmission gear, disabling a vehicle starter motor, disabling a
vehicle throttle, operating a speed governing device, and disabling
an auxiliary function or Power-Take-Off function.
[0064] If the controller 230 determines that the vehicle is in a
SAFE status, then the controller may execute the step of inferring
the driver status 452. One of ordinary skill in the art, however,
will appreciate that the logic steps illustrated in FIG. 7, may be
accomplished in a different order than presented. The steps are
presented in the order shown in FIG. 7 for convenience only.
[0065] The controller 230 may receive data from one or more input
sources 430. Based on the data received, the controller 230 may
determine whether the driver is QUALIFIED or UNQUALIFIED. Inferring
the driver status may include identifying, that the operator is
present and is authorized to operate the vehicle. The data received
from the one or more input sources 430 may be indicative of, but
not be limited to, vehicle door status, ignition key status, driver
restraint status, the status of various switches, the control
status of various vehicle systems, and time histories for each of
the status mentioned.
[0066] A QUALIFIED driver status may include, for example, but not
be limited to, the driver being present in the vehicle, which may
be indicated by a seat switch or driver restraint switch, the
driver being in control of the vehicle (i.e. driver control input
sensed), the driver successfully enabling the vehicle (e.g.
ignition has been keyed-on), and the driver passing an
identification verification (e.g. a proper identification badge has
been swiped or a proper code has been entered). Other criteria,
however, may also be used to define a QUALIFIED status. For
example, the identification verification may include the
qualification level of an individual operator (e.g.
driver-in-training, fully trained, service personnel). An
UNQUALIFIED status, therefore, may be defined as a failure to meet
one or more criteria for a QUALIFIED status.
[0067] If the controller 230 determines that the driver status is
UNQUALIFIED, then the controller may enforce a failsafe function
462. If the controller 230 determines that the driver status is
QUALIFIED, then the controller may execute the step of enabling
appropriate functions 454. Based on the vehicle status and driver
status inferred in steps 450 and 452, respectively, the controller
230 may enable only those functions determined to be APPROPRIATE
and disable those functions determined to be INAPPROPRIATE. The
controller 230 may enable or disable any vehicle functions which it
may control. Examples of functions the controller 230 may control
include, but are not limited to, the park brake function, the work
brake function, transmission gear change, and speed governing.
[0068] As an example, for a SAFE vehicle status and a QUALIFIED
driver status, the controller 230 may enable the work brake
arrangement. As discussed above, a SAFE vehicle status may include
a verification that the vehicle is stopped or only moving slowly
and that the air brake system supply pressure is adequate. Thus,
the overall condition of the vehicle may be appropriate for
utilizing a work brake function. Furthermore, the functions
considered appropriate may depend on the level of qualification of
the operator. For example, service personnel, tow truck drivers,
and drivers-in-training may have different vehicle functions
enabled for them, thus the controller 230 may offer different
operational capabilities based on the level of qualification of the
operator. As shown by the dashed line in FIG. 7, inappropriate
functions may be disabled via the step of enforcing a failsafe
function 462 as described above.
[0069] For those APPROPRIATE functions, the controller 230 may
execute the step of inferring the driver's intent 456. The
controller 230 may receive data from the one or more input sources
430 that may be indicative of driver actuation. For example, a door
switch may indicate that the driver has opened or closed the door,
or a driver restraint switch may indicate that the driver has
fastened or released the seat belt. Based on data indicative of
driver actuation, the controller 230 may infer the driver's intent.
Examples of the driver intent may include, but are not limited to,
the intent to leave the vehicle, the intent to move the vehicle,
the intent to park the vehicle, and the intent of the driver to
work brake the vehicle. Thus, in order to infer driver intent, the
controller 230 may, for example, utilize data indicative of the
door being opened or closed, the ignition key being turned on or
off, the engine being started or stopped, the park brake switch
being actuated, and a certain transmission gear being selected.
[0070] The controller 230 may infer that the driver's intent is
UNSAFE. For example, combinations of driver intent that may be
deemed UNSAFE may include, but not be limited to, the driver
intending to park a moving vehicle, the driver intending to work
brake a vehicle while the park brakes are applied, or the driver
intending to leave a moving vehicle. If the controller 230
determines that the driver's intent is UNSAFE, the controller may
enforce a failsafe function 452.
[0071] If the controller 230 determines that the driver's intent is
SAFE, then the controller may execute the step of checking the
plausibility/safety of the driver's intent 458. The controller 230,
thus, may cross check the inferred intent of the driver as a
plausible request in order to rule out erroneous sensor readings
not able to be detected. In addition, the controller 230 may
execute a safety check that may include, but not be limited to,
checking for switch or sensor failure, checking for electronic
control unit failure, checking for low system voltage or air
pressure, and checking for failure of a communication link.
[0072] Furthermore, during the step of checking the plausibility of
the driver's intent, the controller 230 may check for attempts by
the driver to defeat/override the system, such as for example, the
driver taping a door switch to indicate that it is closed when the
door is actually open. As an example, the controller 230 may infer
that a qualified driver intends to move the vehicle by selecting a
forward gear and opening the throttle. The intent of the driver may
be cross-checked with the status of the park brake and the work
brake. If the park brake or work brake are engaged, the controller
230 may determine that the driver's intent is not plausible (e.g.
the vehicle should not/cannot be operated when the park brake or
work brake are engaged). As a result, the controller 230 may
disable the throttle until the driver releases the park brake or
work brake. Thus, if the controller 230 determines that the
driver's intent is not plausible, then the controller may enforce a
failsafe function 462, as described above. Alternatively, the
controller 230 may automatically release the park brake or work
brake if input data indicates additional conditions are met, such
as for example, the seat is occupied, the door is shut, the
restraint is buckled, the throttle demand is high (possibly
indicating an emergency condition).
[0073] If the controller 230 determines that the driver's intent is
plausible, then the controller may activate the driver-intended
functions 460. Driver-intended functions may be any functions that
the driver/operator would request the vehicle to perform that the
controller 230 may discern or have a priori knowledge of.
Driver-intended functions that the controller 230 may potentially
activate (i.e. allow the driver to manually request) may include,
but not be limited to, applying/releasing the park brake,
applying/releasing the work brake, engaging a non-neutral
transmission gear, actuating the vehicle throttle, operating an
auxiliary function or Power-Take Off function, and cranking the
starter motor.
[0074] The controller 230 may also send an output signal to
enunciate the status of the vehicle during any of the steps
performed by the controller. Thus, output devices capable of
enunciating the vehicle status may be provided in communication
with the controller 230. Status enunciators may include, but not be
limited to, LCD text messages, indicator lights, and audible
devices. For example, operational status indicators, such as a park
brake indictor light or a work brake indicator light, may be
provided. The controller 230 may toggle the operational status
indicators on and off with each successful state transition (e.g.
park brake is released), thus the meaning of the indicators may be
self-teaching to the operator/driver. Audible indicators, such as
for example a pleasant chime, may also accompany visual indicators
or stand alone to reassure the operator that a successful operation
has been completed.
[0075] In addition, fault indicators, such as a park brake fault
light, a work brake fault light arid/or a Limp-to-Roadside
indicator light may be provided. The fault indicators may be tested
during each key-on of the vehicle, but may generally remain off
unless the controller 230 detects a fault or enters the
Limp-to-Roadside mode. Audible indicators (e.g. a disconcerting
buzz) may accompany the visual fault indicators or stand alone to
reinforce that some risk has been detected.
[0076] The invention has been described with reference to the
preferred embodiments. Modification and alterations will occur to
others upon a reading and understanding of this specification. It
is intended to include all such modifications and alterations
insofar as they come within the scope of the appended claims or the
equivalents thereof.
* * * * *