Fluid-pressure and analogous brake systems – Multiple systems – Fluid pressure and electric
Reexamination Certificate
1998-12-31
2001-04-17
Graham, Matthew C. (Department: 3613)
Fluid-pressure and analogous brake systems
Multiple systems
Fluid pressure and electric
C303S015000, C303S020000
Reexamination Certificate
active
06217126
ABSTRACT:
BACKGROUND
The invention relates generally to freight train brake control systems and more particularly to a system for operably interfacing ECP equipped freight cars with non-ECP equipped locomotives.
The North American Railroad industry, lead by the Association of American Railroads (AAR) has developed standards for Electrically Controlled Pneumatic (ECP) brakes. These standards include an electric trainline, 2 wire, 8 gauge, which operates at 230 VDC, for providing power and communications to and from the ECP units on each car. Communications must following Echelon LonWorks standards, using a PLT-10A transceiver. Each car is budgeted at up to 10 watts power consumption, in a train of 160 cars, up to 12,000 ft. length. A separate 230 VDC cable must be provided through each locomotive and a 230 VDC locomotive power supply rated at 2,500 watts is required on at least one of the locomotives to power the ECP system on each car. Additionally, a locomotive ECP “head end unit” (HEU) is required to provide communications, locomotive interfaces, and operator interface with the ECP cars.
The ECP system may be provided as overlay to conventional pneumatic brake valves, or as “all electric,” replacing the pneumatics service portion function. The “all electric” ECP system provides the most economical solution, but requires locomotives to be equipped to support ECP operation. There are usually multiple locomotives for a train, and all are required to be equipped with the 230 VDC ECP trainline cable. The lead locomotive must have the ECP HEU and at least one locomotive has to be equipped with the 230 VDC ECP power supply.
Prior art ECP systems which are of the “overlay” type permit the cars to be operated in normal pneumatics mode braking ECP when ECP equipped locomotives were not available. Additionally, even with “all electric” ECP cars, a “pneumatic emulation” mode can be provided using the ECP system battery or an on-board power source. Pneumatic emulation describes the operation of the ECP system when braking commands are communicated to the ECP equipment pneumatically via the brake pipe in the same manner as conventional pneumatic operation, rather than by an electric command signal. Thus, a non-ECP locomotive can still operate the brakes on ECP cars. The downside of the emulation mode described is that the power source for the ECP system is problematic. If an ECP battery is used there will necessarily be a limited operating life. The alternative, adding on-board power generation, greatly adds to the cost of the system.
In any event, future ECP trains designed to AAR guidelines, with the separate 230 VDC trainline, require each car and all locomotives in the train to be modified. With the exception of small “captive” railroads which do not need to interchange cars and locomotives with others, it is very difficult to manage the transition to full ECP operation. Therefore, each car would have to be equipped to operate with both ECP and conventional pneumatic brake systems. However, for many companies it is not economically viable to equip each car with both ECP equipment and pneumatic control valves. Likewise, it is an economic penalty to require on -board power generation to support electric emulation for conventional pneumatics operation.
Therefore, there is a need for a way to employ ECP cars with non-ECP locomotives without having to rely on the ECP battery or requiring on-board power generation. Accordingly, an apparatus and method is provided for operating the ECP equipment on-board each car in a low power emulation mode which can be powered indefinitely by the standard 74 VDC locomotive battery. Consequently, “all electric” ECP cars can be powered and controlled by standard, unmodified locomotives thereby supporting a gradual transition to “all electric” ECP cars without the need to retrofit every locomotive within a short time period. Additionally, co-pending U.S. patent applications Ser. No. 09/224,543, titled “ECP TRAIN LINE COMMUNICATIONS FOR RAILWAY FREIGHT CAR BRAKES,” filed Dec. 31, 1998, and Ser. No. 09/224,541, titled “RAILWAY LOCOMOTIVE ECP TRAIN LINE CONTROL,” filed on Dec. 31, 1998, which similarly disclose subject matter related to the transition from pneumatic to ECP brake systems, are hereby incorporated herein by reference.
SUMMARY
An apparatus and method for low power ECP brake emulation in a freight train having ECP equipped cars and one or more non-ECP equipped locomotives is provided wherein the ECP equipment on each car is powered by a power source on the locomotive, typically the 74 VDC locomotive battery. To supply power from the locomotive battery to each ECP car, an adapter is employed to connect the locomotive Multiple Unit (“MU”) cable to the ECP trainline wire on each car. In a low power ECP emulation method, sufficient power is provided by the locomotive MU power source to operate the ECP equipment on each car indefinitely. In some embodiments, the ECP battery on each car can even be charged from the locomotive battery. The low power ECP emulation mode utilizes brake pipe sensors communicating with the ECP equipment for receiving pneumatic brake commands via the brake pipe. Power is conserved because the brake pipe sensors can use less power than would be required to power the ECP transceivers on each car to receive the brake signals electrically. The basic method includes interfacing the locomotive MU cable to the ECP wire, implementing a low power ECP emulation mode wherein pneumatic signals sent via the brake pipe are detected by pressure sensors and communicated to the ECP control valves for regulating brake cylinder pressure accordingly. According to the method power consumption is further minimized by providing power to only the brake pipe sensors and minimal ECP electronics to monitor pressure changes, and thereafter activating other sensors and controls only as needed.
Other details, objects, and advantages of the invention will become apparent from the following detailed description and the accompanying drawings figures of certain embodiments thereof.
REFERENCES:
patent: 4344138 (1982-08-01), Frasier
patent: 4687258 (1987-08-01), Astley
patent: 5064251 (1991-11-01), Romansky
patent: 5172316 (1992-12-01), Root et al.
patent: 5503469 (1996-04-01), Cunkelman
patent: 5630565 (1997-05-01), Lumbis
patent: 5681015 (1997-10-01), Kull
Buchanan Ingersoll P.C.
Graham Matthew C.
Westinghouse Air Brake Technologies Corporation
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