Lubrication – Rail or rail vehicle wheel lubricator – On vehicle
Reexamination Certificate
2000-06-15
2001-01-09
Fenstermacher, David (Department: 3682)
Lubrication
Rail or rail vehicle wheel lubricator
On vehicle
C188S038000
Reexamination Certificate
active
06170610
ABSTRACT:
BACKGROUND OF THE INVENTION
Kumar and Kumar (U.S. Pat. No. 4,390,600) invented an intelligent on-board lubrication system for curved and tangent track. They proposed a method of applying the lubricant to the rail by using a separate spring loaded lubrication wheelset to which the lubricant is applied first. This wheelset then applies the lubricants to the rail. The rate of lubricant application is controlled by a microprocessor and a number of operating parameters of the train and the track on which it is operating. Kumar and Kumar later invented a method of applying the lubricants directly to the rail (U.S. Pat. No. 5,477,941). In this invention they proposed to apply two lubricants, one Top-of-Rail (TOR) and another Rail Gage Side (RAGS). In both inventions, the computer logic controlling the rate of lubrication was the same. The rate of lubrication R, was controlled by the relation R=K*R
D
*R
L
*V*Nw where K is an equipment factor constant; R
D
is a curve factor based on the relation R
D
=K
D
*D (K
D
is a constant and D is the degree of the rail curve); R
L
is a lubricant factor based on R
L
=C
L
*T (C
L
is a constant and T is the ambient temperature); V is the train velocity; N is the number of car axles and w is the average tons/car axle; i.e. Nw represents the total trailing car tons of the train. The above inventions advanced the state of the art in rail lubrication significantly. However, a number of new advances have been made recently. These are subjects of the present invention.
SUMMARY OF THE INVENTION
This invention uses only Top-of-Rail (TOR) lubrication on both rails without rail gage side (RAGS) lubrication. The TOR lubricant is applied with great accuracy in computer-controlled, precise quantities behind the last axle of the last locomotive such that the lubricant is consumed by the time the entire train has passed under all track, speed, temperature and train size conditions. For a TOR lubrication system, it is important that the lubricant is computed and applied accurately so that no lubricant is wasted, maximum benefit is achieved and no lubricant is left on the rail after the train has passed. This invention therefore makes use of a technique referred to henceforth as the hydraulic pulse-width modulation method (PWM or %PWM) that controls the quantity of lubricant delivered. This method is much more accurate than the various conventional pumps. This method is also cheaper and has a much higher reliability, because it uses only one moving part. In this method, time is divided into a series of windows each consisting of a few seconds. Lubricant delivered from a pressurized tank through long hoses to a solenoid controlled valve is then metered by the duration within this time window for which the computer computes and opens the valve.
Because of the wide temperature range encountered in railroad operations, the lubricant viscosity can change significantly. These viscosity changes, coupled with the long hoses needed in a locomotive, can cause large variations in the hose resistance to lubricant flow. These variations must be compensated for to obtain the correct lube delivery rate. This invention therefore provides a viscosity/temperature compensation method in which a viscosity versus temperature curve of the lubricant along with some field tests provide a correlation in the open time of the solenoid valve (%PWM) in each time window so that the design value of the lubricant is delivered to the rail even though lubricant temperature may vary through a broad range.
If the temperatures fall to very low values, insufficient lubricant comes out of the nozzles even with the solenoid valves fully open in all time windows. This invention then uses an electronic or electromechanical pressure regulator to change the pressure in the tank to let enough lubricant flow under low temperature conditions.
This invention also defines a method of more accurately determining the effect of tonnage in the train on the rate of lubrication. It involves experimentally measuring the rail head adhesion coefficient after the train has passed for several rates of lubrication for each tonnage train. For the correct lubrication rate for a given tonnage train, the adhesion coefficient on the rail after the train has passed, will be above 80% of the value achieved on a clean dry rail. These values are tabulated for each tonnage and the table is stored in the memory of the locomotive's computer for calculation. Before starting the train, the engineer enters the tonnage of the train on the computer keypad. The computer then uses the internal table to select the proper correction factor for tonnage.
The present invention also uses a new logic for turning off the lubrication when dynamic or air brakes are applied on a train. By using this new invention, the intelligent rail lubrication method can be made more economical, more effective, more accurate, and more reliable.
The improved equation for the application of the lubricant to the top of the rails is:
%PWM=K*R
D*
f
1
(T
L
)*V*f
2
(W) where f
1
(T
L
) is a function of lube temperature and f
2
(W) is a function of train tonnage.
REFERENCES:
patent: 4393957 (1983-07-01), Hawthrone
patent: 5477941 (1995-12-01), Kumar et al.
patent: 5896947 (1999-04-01), Kumar
Fenstermacher David
McEachran, Jambor, Keating, Bock & Kurtz
Tranergy Corporation
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