closed a volume of brake fluid is displaced out of outlets 106 and 107 into the hydraulic accumulator this causes compression of compressible element 112 and the accumulator receives brake fluid as soon as the accumulator is filled valve 109 is closed brake booster 104 is reset and is therefore available for braking the level of the accumulator pressure and therefore the fluid level of the accumulator may be measured by a pressure sensor already present such as the inlet pressure sensor or the brake circuit pressure sensor the decision of when if the accumulator is charged may be charged may be linked for example to the accelerator position if the accelerator position exceeds a limiting value then the accumulator is charged for the braking feel it is important to maintain the relationship between pedal travel and total braking torque of the vehicle regardless of the gap present at the start of the braking to that end in the case of braking by the driver directly after a manipulation of the brake pedal by the driver is sensed and the connection of the master brake cylinder to the reservoir not drawn in is thereby broken valve 109 is opened and accumulator 108 displaces a volume of brake fluid into the brake system and in this manner provides for a pressure increase at the wheel brake cylinders which results in an at least partial reduction of the gap.