Patent ID: 7325883

Claim:
A hydraulic braking system for supplying a first and second pressurized fluid from a tandem master cylinder to a first and second wheel brake, the braking system comprising: a first braking circuit including a first brake line receiving the first pressurized fluid from the master cylinder through a first normally-open isolation valve and selectively connected to the first wheel brake through a first normally-open inlet valve, and a first pressure relief line selectively connected to the first brake line downstream of the first inlet valve through a first normally-closed outlet valve, wherein the first pressure relief line includes a first pump having an inlet and an outlet; a second braking circuit including a second brake line receiving the second pressurized fluid from the master cylinder through a second normally-open isolation valve and selectively connected to a second wheel brake through a second normally-open inlet valve, and a second pressure relief line selectively connected to the second brake line downstream of the second inlet valve through a second normally-closed outlet valve, wherein the second pressure relief line includes a second pump having an inlet and an outlet; and a bypass line having two operative connections connecting the first braking circuit to the second braking circuit, wherein the bypass line includes only one electrically-operated bypass valve, the electrically-operated bypass valve being normally-closed, and the bypass line being operatively connected at one connection to the first braking circuit at a bypass location on the first pressure relief line downstream of the first outlet valve and upstream of the inlet of the first pump, and the bypass line being operatively connected at the other connection to the second braking circuit at a bypass location on the second pressure relief line downstream of the second outlet valve and upstream of the inlet of the second pump, whereby opening the electrically-operated bypass valve establishes a single fluid flow path between the first and second pressure relief lines.