Air dryer reservoir module components
An air dryer and reservoir assembly for providing compressed air from an air compressor (20) on a heavy motor vehicle which includes an air dryer (14) connected to receive compressed air from the air compressor (20) and a secondary reservoir (12), including an integral purge volume (34), for storing compressed air which passes through the air dryer (14), with the air dryer (14) and the secondary reservoir (12) being securely attached to a housing (16) to form an air dryer reservoir module (10). A primary reservoir (18) for storing compressed air from the air dryer (14) is located remote from the air dryer reservoir module (10). A pressure equalizing mechanism (57) is disposed between the primary reservoir (18) and the secondary reservoir (12) for keeping pressure in the two reservoirs (12,18) equal. Components located within the housing (16) control air flow between the air dryer (14) and the primary and secondary reservoirs (18,12) and also monitor the pneumatic brake system circuits fed by the primary and secondary reservoirs (18,12).
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This application is a continuation of U.S. patent application Ser. No. 09/030,583, filed Feb. 25, 1998 now U.S. Pat. No. 6,074,462, which is a continuation-in-part of U.S. patent application Ser. No. 08/993,931, filed Dec. 18, 1997 now U.S. Patent No. 5,917,139.
BACKGROUND OF THE INVENTION1. Field of the Invention
This invention relates to air dryers and more particularly to an air dryer and a reservoir, including a separate purge volume, constructed together as a module.
2. Description of Prior Art
Air dryers have been used to dry the air in a heavy vehicle air brake system for many years. The advantages of clean and dry air in air brake systems has long been recognized, as moisture entrained in the air brake system may during cold weather operation cause the components of the air brake system to freeze, thus rendering the system inoperable. These prior art air dryers normally include a desiccant material through which the compressed air flows. When the vehicle air compressor has charged the vehicle air reservoirs to a sufficient pressure level, the compressor is unloaded so that the compressor no longer compresses air. When the compressor is unloaded, a signal is transmitted to a purge valve carried within the air dryer which causes stored compressed air to backflow through the desiccant at a controlled rate to regenerate the desiccant. The air used to regenerate the desiccant can be either from compressed air stored in an integral purge volume within the air dryer or from compressed air stored in a separate reservoir.
Most prior art compressed air systems for heavy vehicle air brake applications use three reservoirs which are separate from the air dryer. A compressor feeds compressed air to the air dryer which after flowing through the desiccant bed is fed to a remote supply reservoir. The supply reservoir is connected to feed compressed air to a primary reservoir and a secondary reservoir. The primary and secondary reservoirs feed pneumatic circuits which can control the air brake system of the vehicle. For protection from loss of air pressure the primary and secondary reservoirs each include a check valve in their pneumatic connections to the supply reservoir. A pneumatic control line extends from the supply reservoir to an air pressure governor which controls loading and unloading of the air compressor.
SUMMARY OF THE INVENTIONThe present invention is for an air dryer and reservoir assembly, for providing compressed air from an air compressor for operating the brakes of a heavy motor vehicle, which includes an air dryer connected to receive compressed air from the air compressor, a secondary air reservoir separate from the air dryer, a housing containing pneumatic circuit components for controlling the flow of compressed air from the air compressor through the air dryer to the secondary reservoir having the air dryer securely attached to one section thereof and the secondary reservoir securely attached to another section thereof for securing the air dryer and the secondary reservoir together as a unitary air dryer reservoir module. The compressed air brake system with the air dryer reservoir module also includes a primary air reservoir having a pneumatic connection to the housing disposed remote from the secondary air reservoir with the housing containing pneumatic circuit components for controlling compressed air flow between the air dryer and the primary air reservoir. Pneumatic circuit protection valves are disposed within the housing for monitoring the pneumatic circuits fed by the primary and secondary reservoirs. A failure detection means is also disposed within the housing for detecting a failure of the pneumatic circuits which are fed by the primary and secondary reservoirs and in the event of a failure of these pneumatic circuits the speed of the heavy vehicle is limited.
The herein disclosed air brake system's air charging and treatment sub-system referred to as the air dryer reservoir module provides for a simplified and cost effective air charging sub-system, using integrated components. The air dryer reservoir module is configured in a way that allows the elimination of the supply reservoir, which is used in the standard three reservoir system, while providing a means of simultaneously sensing both the primary reservoir and the secondary reservoir for air compressor and air dryer control.
The air dryer reservoir module integrates components such as pressure protection valves, the air compressor governor, pressure relief valves, pressure sensors and the like in a way that eliminates the need for the supply reservoir, the supply reservoir safety valve, several of the standard three reservoir system's external lines and many of its fittings. The reduction of components, fittings and pneumatic lines reduces potential failure modes. With respect to a standard three reservoir system, the air dryer reservoir module integrates the following components: air dryer, primary and secondary check valves, supply and secondary drain valves, supply reservoir safety valve, the compressor governor, auxiliary system pressure protection valves, and the supply and secondary reservoirs.
A purge volume can be built into the end of the secondary reservoir to which the air dryer is attached. An internal baffle separates the secondary reservoir volume from the purge volume. Internal communication passages connect the secondary reservoir and purge volume to the air dryer. The dryer reservoir module can also be constructed to equalize the pressure between the primary reservoir and the secondary reservoir, such that if the vehicle is parked for a given period of time the pressure cannot be replenished. Thereby limiting the use of the vehicle with a severely leaking reservoir.
For a better understanding of the invention reference may be had to the preferred embodiments exemplary of the inventions shown in the accompanying drawings in which:
Referring now to the drawings and
Referring to
Comparing
The air dryer reservoir module is different from the prior art in that it integrates charging system components in a way that eliminates components, pneumatic lines and pneumatic connections thereby reducing failure modes. The air dryer reservoir module 10 is thought to be the first of its kind to utilizes the ABS/EBS brake system ECU to communicate system failures to the engine ECU to instruct the engine to limit vehicle speed. The air dryer reservoir module 10 concept eliminates the supply tank 60 thereby allowing the primary and secondary service tanks 12 and 18 to communicate directly with the integrated air dryer 14 through protection valves 35 and 36. This allows the protection valves 35, 36 to be integrated into the air dryer module 10, reducing external components and pneumatic lines.
Referring now to
The air dryer reservoir module 10 can be designed to utilize service reservoir air to purge the desiccant, i.e., supply purge. The operation of the air dryer reservoir module 10 in a supply purge mode will be similar to that of an AlliedSignal AD-SP air dryer. The integral pressure protection valves 35, 36 will eliminate the need for externally plumbed protection valves. The internal protection valves 35 and 36, when open will allow air to flow back to a special two position three way system purge solenoid, located where the three way solenoid 39 is in the integral purge design. The special two position three way system purge solenoid will be controlled by the BBS ECU with inputs from the pressure sensors 37 through sensor/solenoid I/O 44. The system purge solenoid will be designed to communicate a control signal to the compressor 20 unloader and the air dryer purge valve 32 independently. At cutout pressure the system purge solenoid will unload the compressor and open the purge valve 32. The system purge solenoid will then close only the purge valve 32 after a predetermined amount of system air is used to purge the dryer's desiccant bed 33. At cutin pressure the system purge solenoid will then load the compressor 20 starting the cycle over.
Referring now to
The primary protection valve 35 is set to open at 103±3 psi and to close at approximately 95 psi. The secondary protection valve 36 is set to open at 109±3 psi and to close at approximately 100 psi. When both protection valves 35 and 36 are open, the primary reservoir 18 and the secondary reservoir 12 are in free fluid communication. Secondary reservoir 12 provides compressed air to a vehicle leveling supply port through an accessory protection valve 41 which is set to open at 85±3 psi and to close at approximately 72 to 83 psi. Secondary reservoir 12 also provides compressed air to vehicle accessories through an accessory protection valve 43 which is set to open at 55±3 psi and to close at approximately 45 to 55 psi.
The air dryer reservoir module 10 is designed to accommodate the requirements of both FMVSS 121 and EEC regulation No. 13. The air dryer reservoir module 10 is also designed to interact with the ABS/EBS system's J1939/J1922 engine serial link to allow the limiting of vehicle speed in the event of a single circuit brake system failure, either primary or secondary. The air dryer reservoir module 10 reduces the number of OEM installed charging sub-system components, pneumatic lines and connections as follows: Major charging system components—four for air dryer reservoir module 10 vs. thirteen for a three reservoir system; pneumatic lines—three for air dryer reservoir module 10 vs. six for a three reservoir system; and pneumatic connections—thirteen for air dryer reservoir module 10 vs. thirty two for a three reservoir system.
Referring now to
With a leaking reservoir 12 or 18 the dryer reservoir module 10 described above will recharge the surviving reservoir indefinitely, thereby holding off the spring brakes. The driver can choose to operate the vehicle with limited braking efficiency for an unlimited period of time even though one of the reservoirs does not hold pressure. In another embodiment the dryer reservoir module 10 can be constructed to equalize the pressure between the reservoirs 12 and 18, such that if the vehicle is parked for a given period of time the pressure cannot be replenished thereby limiting the use of the vehicle with a severely leaking reservoir.
As shown in FIG. 6 and described above, pressure protection valves 35 and 36 are used to supply compressed air to the primary reservoir 18 and the secondary reservoir 12. The pressure protection valves 35, 36 are set to pressurize the primary reservoir 18 first, provided the same pressure exists within the primary and secondary reservoirs. At full system pressure the pressure protection valves 35, 36 are open, insuring equal pressure in both the primary and secondary reservoirs 18 and 12. However, the pressure protection valve opening pressure is dependent upon the downstream reservoir pressure, therefore, if the reservoir pressures are not equal the pressure protection valve which has the highest downstream pressure will open first. Parking the vehicle overnight or for extended periods of time may cause the primary and secondary reservoir pressures to become unequal. During recharging of the air system the secondary reservoir 12 may charge before the primary reservoir 18. It may be desirable to limit the duration the vehicle can be operated in the condition where one reservoir has significantly reduced pressure. By using a pressure equalizing mechanism, such as a connecting line with a suitable orifice 57, the pressures in the reservoirs 12 and 18 slowly become equal so that during recharging of the air system the primary reservoir 18 will charge first. Furthermore, if the primary reservoir 18 has become ruptured or has a severed leak, again the pressure in both reservoirs 12 and 18 will migrate to 0 psi; however, the primary reservoir 18 can be recharged, but the essential accessories and air suspension will not be pressurized because the secondary reservoir 12 cannot be recharged. The pressure equalizing mechanism 57 will cause the pressure in both reservoirs 12 and 18 to be equal, thereby charging the primary reservoir 18 first and limiting the use of the vehicle after a severe leak in either the primary or secondary reservoirs 18 and 12.
Claims
1. A method for pressurizing and depressurizing a compressed air reservoir including a purge chamber in fluid communication with an air dryer, a service chamber in fluid communication with the air dryer, and a baffle defining the purge and service chambers, the method comprising:
- pressurizing the purge chamber with first dried compressed air from the air dryer;
- pressurizing the service chamber with second dried compressed air from the air dryer without commingling the first dried air and the second dried air; and
- depressurizing the purge chamber to regenerate the air dryer.
2. The method for pressurizing and depressurizing a compressed air reservoir as set forth in claim 1, further including:
- depressurizing the service chamber to operate a compressed air system.
3. The method for pressurizing and depressurizing a compressed air reservoir as set forth in claim 1, wherein the purge chamber is pressurized before the service chamber.
4. The method for pressurizing and depressurizing a compressed air reservoir as set forth in claim 1, wherein pressurizing the service chamber includes:
- controlling a valve between the service chamber and the air dryer.
5. The method for pressurizing and depressurizing a compressed air reservoir as set forth in claim 1, wherein depressurizing the purge chamber includes:
- transmitting the first dried compressed air from the purge chamber to the air dryer without commingling the first dried air and the second dried air.
6. A compressed air reservoir, comprising:
- a purge chamber;
- a service chamber;
- a baffle defining the purge and service chambers;
- a first passageway for transmitting first dried compressed air between a dryer and the purge chamber; and
- a second passageway for transmitting second dried compressed air between the dryer and the service chamber, the second dried compressed air being transmitted between the dryer and the service chamber without passing through the first passageway.
7. The compressed air reservoir as set forth in claim 6, further including:
- a valve, which controls passage of the second dried compressed air between the dryer and the service chamber via the second passageway.
8. The compressed air reservoir as set forth in claim 7, wherein the valve is a protection valve.
9. The compressed air reservoir as set forth in claim 6, wherein the first dried compressed air in the purge chamber is transmitted to the dryer via the first passageway for regenerating a desiccant in the dryer.
10. The compressed air reservoir as set forth in claim 9, wherein circuit components cause the first dried compressed air to pass from the dryer to the purge chamber before the second dried compressed air passes from the dryer to the service chamber.
11. The compressed air reservoir as set forth in claim 6, wherein the second passageway is a tube between the dryer and the service chamber.
12. The compressed air reservoir as set forth in claim 11, wherein the tube passes through the purge chamber.
13. The compressed air reservoir as set forth in claim 6, wherein a volume of the purge chamber is smaller than a volume of the service chamber.
14. A compressed air reservoir, comprising:
- a purge chamber;
- a service chamber;
- a baffle defining the purge and service chambers;
- a first passageway for transmitting first dried compressed air between an air dryer and the purge chamber; and
- a second passageway for transmitting second dried compressed air between the dryer and the service chamber, the second dried compressed air being transmitted between the dryer and the service chamber without passing through the purge chamber.
15. An air reservoir for use on a motor vehicle, comprising:
- a first section;
- a second purge section;
- a divider between the first and second purge sections;
- a first connection connecting the first section to a source of compressed air; and
- a second connection connecting the second purge section to the source of compressed air, the first connection not connecting the first section to the second purge section and the second connection not connecting the second purge section to the first section.
16. The air reservoir for use on a motor vehicle as set forth in claim 15, wherein the divider creates an air-tight seal between the first and second purge sections.
17. The air reservoir for use on a motor vehicle as set forth in claim 15, wherein a volume of the second first section is larger than a volume of the first purge section.
18. The air reservoir for use on a motor vehicle as set forth in claim 15, further including:
- a valve for controlling communication between the second first section and the source of compressed air.
19. The air reservoir for use on a motor vehicle as set forth in claim 15, wherein the second first connection is routed through the first purge section.
20. The air reservoir for use on a motor vehicle as set forth in claim 19, wherein the second first connection is a tube.
21. The air reservoir for use on a motor vehicle as set forth in claim 15, wherein the first and second connections connect the first and second purge sections, respectively, to the source of compressed air via an air dryer.
22. An air supply system for a motor vehicle brake system, comprising:
- a compressor for supplying compressed air;
- an air dryer connected to receive compressed air from the air compressor, the dryer including a desiccant bed through which the compressed air flows for providing a dry compressed air source for operating the brake system; and
- a reservoir, including: a first section; a second purge section; a baffle defining the first and second purge sections; a first passageway connecting the first section to the source of the dry compressed air; and a second passageway connecting the second purge section to the source of the dry compressed air, the dry compressed air being transmitted between the source and the second purge section without passing through the first section.
23. The air supply system for a motor vehicle brake system as set forth in claim 22, further including:
- a housing having a first section connected to the dryer and a second section connected to the reservoir for joining the dryer and the reservoir as a unitary unit.
24. The air supply system for a motor vehicle brake system as set forth in claim 22, wherein:
- a first portion of the dry compressed air is transmitted between the dryer and the first section via the first passageway; and
- a second purge portion of the dry compressed air is transmitted between the dryer and the second purge section via the second passageway.
25. The air supply system for a motor vehicle brake system as set forth in claim 24, wherein:
- the first portion of the dry compressed air is not transmitted to the second purge section; and
- the second purge portion of the dry compressed air is not transmitted to the first section.
26. The air supply system for a motor vehicle brake system as set forth in claim 24, wherein the first portion of the dry compressed air is transmitted from the first section to the dryer for regenerating the desiccant bed.
27. The air supply system for a motor vehicle brake system as set forth in claim 26, wherein the second first portion of the dry compressed air is transmitted to the brake system.
28. The air supply system for a motor vehicle brake system as set forth in claim 26, wherein circuit components cause the first purge portion of the dry compressed air to be transmitted from the dryer to the first purge section via the first second passageway before the second first portion of the dry compressed air is transmitted from the dryer to the second first section via the second first passageway.
29. The air supply system for a motor vehicle brake system as set forth in claim 26, wherein a volume of the first purge section is smaller than a volume of the second first section.
30. The air supply system for a motor vehicle brake system as set forth in claim 24, further including:
- a valve for controlling the transmission of the second first portion of the dried compressed air between the dryer and the service chamber first section.
31. The air supply system for a motor vehicle brake system as set forth in claim 30, wherein the valve is positioned within the second passageway.
32. The air supply system for a motor vehicle brake system as set forth in claim 22, further including a second reservoir connected to the source of the dry compressed air.
33. The air supply system for a motor vehicle brake system as set forth in claim 22, wherein the air dryer is remote from the reservoir.
34. A reservoir used in combination with an air dryer in a compressed air system, the reservoir comprising:
- a first chamber for storing first compressed dried air used for regenerating a desiccant within the dryer;
- a second chamber for storing second compressed dried air for use in a pneumatic system;
- a baffle between the first and second chambers;
- a first passageway for transmitting the first compressed dried air between the dryer and the first chamber, the first compressed dried air not being transmitted to the second chamber; and
- a second passageway for transmitting the second compressed dried air between the dryer and the second chamber, the second compressed dried air not being transmitted to the first chamber.
35. The reservoir used in combination with an air dryer in a compressed air system as set forth in claim 34, further including:
- a valve for controlling the transmission of the second compressed air between the dryer and the second chamber.
36. The reservoir used in combination with an air dryer in a compressed air system as set forth in claim 35, wherein the valve causes the first compressed dried air to be stored in the first chamber before the second compressed dried air is stored in the second chamber.
37. The reservoir used in combination with an air dryer in a compressed air system as set forth in claim 34, wherein the second passageway is a tube passing through the baffle.
38. The reservoir used in combination with an air dryer in a compressed air system as set forth in claim 37, wherein the tube passes through the first chamber.
39. An air reservoir for use on a motor vehicle, comprising:
- a first section in independent fluid communication with a source of compressed air;
- a second purge section in independent fluid communication with the source of compressed air; and
- a divider between the first and second purge sections.
40. The air reservoir as set forth in claim 39, wherein the first section is not in independent fluid communication with the second purge section.
41. An air reservoir for use on a motor vehicle, comprising:
- a first section;
- a second purge section;
- a divider between the first and second purge sections;
- a first passageway independently fluidly connecting the first section to a source of compressed air; and
- a second passageway independently fluidly connecting the second purge section to the source of compressed air, the first passageway not independently fluidly connecting the first section to the second purge section and the second passageway not independently fluidly connecting the second purge section to the first section.
42. The air reservoir for use on a motor vehicle as set forth in claim 41, further including:
- a valve for controlling the fluid communication between the second first section and the source of compressed air via the second first passageway.
43. The air reservoir for use on a motor vehicle as set forth in claim 41, wherein the second first passageway is passes through the first purge section.
44. The air reservoir for use on a motor vehicle as set forth in claim 43, wherein the second first passageway is a tube.
45. An air supply system for a motor vehicle brake system, comprising:
- a compressor for supplying compressed air;
- an air dryer connected to receive compressed air from the air compressor, the dryer including a desiccant bed through which the compressed air flows for providing a dry compressed air source for operating the brake system; and
- a reservoir, including: a first section; a second section; a baffle defining the first and second sections; a first passageway connecting the first section to the source of the dry compressed air; and a second passageway connecting the second section to the source of the dry compressed air, the dry compressed air being transmitted between the source and the second section without passing through the first section during a first operating mode.
46. The air supply system as set forth in claim 45, wherein, during the first operating mode, a first portion of the compressed air is stored in the first section before a second portion of the compressed air is stored in the second section.
47. The air supply system as set forth in claim 46, wherein the second portion of the dry compressed air is transmitted from the first section to the second section during a second operating mode.
48. The air supply system as set forth in claim 47, wherein the first portion of the dry compressed air is transmitted from the first section to the dryer for regenerating the desiccant bed during the first operating mode.
49. The air reservoir for use on a motor vehicle as set forth in claim 15, wherein the first section is a service section.
50. The air supply system for a motor vehicle brake system as set forth in claim 22, wherein the first section is a service section.
51. The air reservoir as set forth in claim 39, wherein the first section is a service section.
52. The air reservoir for use on a motor vehicle as set forth in claim 41, wherein the first section is a service section.
53. The air supply system as set forth in claim 45, wherein the first section is a service section.
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Type: Grant
Filed: Nov 24, 2003
Date of Patent: Jan 16, 2007
Assignee: Bendix Commercial Vehicle Systems LLC (Elyria, OH)
Inventors: Leonard A. Quinn (Lagrange, OH), Fred W. Hoffman (Columbia Station, OH), David J. Goodell (Beaverton, OR)
Primary Examiner: Frank M. Lawrence
Attorney: Calfee, Halter & Griswold LLP
Application Number: 10/721,023
International Classification: B01D 53/04 (20060101); B01D 53/26 (20060101);