Brake control system for combining electric and fluid pressure brakes

摘要

A railway car braking system employing a pneumatic brake to supplement the primary electric brake is provided with a feedback signal corresponding to the effectiveness of the electric brake. This feedback signal is compared with the brake command signal to derive a deficiency signal, in accordance with which the pneumatic brake is applied. A detector senses a change in the deficiency signal in decreasing sense for applying a correction factor to the deficiency signal, thereby compensating for hysteresis typically associated with the various valves in the pneumatic brake system, in order to obtain consistent pneumatic braking for a given deficiency signal during both an increase and a decrease of the pneumtic braking level.