Brake system for automotive vehicles with electronically controlled brake force distribution and with anti-lock control

A hydraulic antilock brake system for the front and rear wheels of an automotive vehicle with a front and rear brake distribution control comprising:

• a foot operated braking pressure generator;
• an auxiliary pressure supply;
• a pressure compensation reservoir;
• at least one front wheel brake in fluid communication with said pressure generator and auxiliary pressure supply through a normally open electromagnetically actuatable inlet valve and with said reservoir through an electromagnetically operable normally closed outlet valve;
• at least one rear wheel brake in fluid communication with said pressure generator and said auxiliary pressure supply through a normally closed electromagnetically actuatable main inlet valve, and in fluid communication with said reservoir through a normally-closed electromagnetically actuatable outlet valve;
• front and rear wheel sensor generating signals corresponding to said front and rear wheel rotational behavior;
• a control circuit operative to generate inlet and outlet valve actuation signals in response to said sensor signals to operate said front and rear inlet and outlet valves so as to eliminate slip conditions;
• a supplemental normally open electromagnetically actuatable inlet valve connecting said pressure generator and auxiliary pressure supply in parallel to said main inlet valve;
• a brake force regulator connected in series with said supplemental inlet valve operative to regulate rear wheel brake pressure relative to front wheel brake pressure with said supplemental inlet valve open;
• said control circuit operative to close said supplemental inlet valve and open said main inlet valve upon initiation of brake actuation.