Abstract: A pre-engagement unit for a braking pressure modulator for a pressure regulating circuit of an electronic braking system includes an electrically actuated valve system with three substantially identical 2/2-way solenoid valves. First and second terminals of the 2/2-way solenoid valves are selectively connected to the pneumatic inlets and output terminals of the pre-engagement unit, and to each other so that the first 2/2-way valve serves as an air admission valve for supply pressure, the second 2/2-way solenoid valve serves as an air admission/exhaust valve for redundancy pressure, and the third 2/2-way solenoid valve serves as an exhaust valve. Thereby, the pressure in the pressure regulating circuit can be increased, decreased, or maintained. Desirably, the first, second, and third 2/2-way solenoid valves are connected in parallel to each other.

Abstract: A valve system for the pre-engagement unit of a vehicle braking pressure modulator contains solenoid valves, which are controlled by an electronic braking system. Pneumatic pressure is fed into a brake cylinder on the vehicle wheels via a pressure regulating channel of the pre-engagement unit. The solenoid valves are configured as cartridge solenoid valves, so that assembly is simplified, and utilization of elastic tolerance compensating elements is unnecessary. A preferred embodiment includes three cylinder bodies connected end-to-end with no increase in cylinder diameter. This embodiment enables the use of identical armatures and identical magnet coils for different valve types, such as 3/2-way solenoid valves or 2/2-way solenoid valves. Also, these valves may be configured as normally open or normally closed, with identical outside dimensions. As such, three cartridge solenoid valves can be combined into a compact triple valve cartridge unit that further simplifies the assembly process.