Fluid-pressure and analogous brake systems – Multiple control – Fluid and electric
Patent
1992-10-26
1995-04-11
Graham, Matthew C.
Fluid-pressure and analogous brake systems
Multiple control
Fluid and electric
303 20, 303 59, B60T 1366
Patent
active
054051827
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to an adaptive brake control for indirectly acting compressed air brakes with an electropneumatic engineman's brake valve.
BACKGROUND OF THE INVENTION
The U.S. Pat. No. 4,859,000 shows an adaptive brake control with an electropneumatic engineman's brake valve and a relay valve. In the flow connection between the relay valve and a main air pipe (called HL hereinafter) there are three sensors, which measure the flow rate, the absolute pressure and the temperature of the air. Other pressure transducers at the engineman's brake valve measure the pressure of a control pressure container for the relay valve (A pressure) and the pressure in the engineman's brake valve for the requested brake pressure. The output signals of all of these sensors are fed to a microprocessor and evaluated. Primarily the volume of air flowing into the HL by way of the relay valve when the brakes are released or the volume of air flowing out of the HL by way of the relay valve during the braking process is measured.
When a new train is assembled, starting from a totally vented HL, the volume of the supplied air up to the total release of the train is measured and the value is stored. When the HL is later totally vented, a comparison is made as to whether the same volume flowed out. Inversely, it can also be determined later with this comparative value, whether the brakes were completely released. With each braking and releasing manoeuvre, the volume flowing out of the HL during the braking process is always compared with the volume flowing into the HL during the braking process, from which comparative value the changes in the train configuration (e.g. foreseeable closing of a shutoff valve on a wagon) or other failures can be detected. Furthermore, this document deals in detail with the problem of a renewed braking at a time at which the brakes are not yet completely released, thus air is still being backfed into the HL. In such a case the control pressure container (A container) is already filled up to the pressure for the new braking demand signal, whereas the pressure in the HL is still below this value. By braking again in the release phase, the pressure in the A container is reduced relatively rapidly in accordance with the selected brake step. The control valves of the individual wagons respond to the pressure differential between the current pressure in the A container and the HL pipe, a feature that leads to no braking or only to a braking with a smaller brake step than that selected. To solve this problem, in this publication the value of the pressure in the A container is stored at a time at which the flow rate of the backfed air into the HL goes towards zero. At this time the pressures in the A container and the HL are about equal. For the subsequent braking process the value of the pressure in the A container is corrected in accordance with the difference between the closed loop control pressure in the A container and the stored value. For the subsequent braking process one starts then with less A pressure so that the effective pressure drop in the HL that is necessary for the braking process corresponds to the demanded brake step.
This known system assumes that in the individual wagons no air is consumed, rather the volume of air flowing out of the HL during the braking process is always equal to the volume of air required to subsequently totally release said brake. This requirement, however, is not met for brake systems produced in conformity with the UIC standard, since the air flowing during the braking process out of the air supply containers (R containers hereinafter) in the individual wagons to the brake cylinders does not flow back any more into the R containers or the HL when the brakes are released but rather is vented to the open air. Thus, each brake and release cycle results in a consumption of air. This air consumption depends on the length of the train (number of brake cylinders), the chosen brake step, eventual leakiness of the brake system and indirectly also
REFERENCES:
patent: 4319787 (1982-03-01), Wickham
patent: 4538228 (1985-08-01), Brearey et al.
patent: 4678241 (1987-07-01), Tamamori et al.
patent: 4859000 (1989-08-01), Deno et al.
patent: 4904027 (1990-02-01), Skantar et al.
patent: 4964679 (1990-10-01), Rath
Ewe Ulrich
Saumweber Eckart
Graham Matthew C.
Knorr-Bremse AG
LandOfFree
Method and apparatus for controlling a brake valve based on sens does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for controlling a brake valve based on sens, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for controlling a brake valve based on sens will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1534375