Adaptive high-precision pressure supply – DAP pump technology

E139 (4 inventions, priority September 2013) and E136 (6 inventions, same priority period, both PCT September 2014) form the core layer of the adaptive pressure supply. E139 establishes the universal double-stroke piston pump architecture: a double-acting piston with at least two differently sized effective areas, connected via a short connecting line to one or more high-flow switching valves (AV) connected in parallel, enables adaptive delivery capacity through area switching — large area for fast pre-filling at low pressures, small area for high-precision pressure dosing at high pressures. The technically optimized area ratio of 1.5:1 to 2.5:1 (typically 2:1) doubles the delivery rate while halving the motor torque. The E139 patent family protects this universal pump without restriction to brake systems in EP, US, CN, KR, JP, IN, GB, and FR.

E136 transfers the DAP principle to an application-oriented pressure supply unit for vehicle systems with variable delivery and area switching. The six core innovations cover both device and process aspects: the basic system with 3/2-way valve arrangement for bidirectional operation, an operating method for dynamic pressure modulation, and specific valve arrangements for controlling area switching. The property rights in DE, US, and CN provide robust geographical coverage for the core markets of the automotive industry.

Fully integrated brake actuation system – DAP as central pressure source

E138 (8 inventions, priority May 2014), E138c (5 inventions, priority August 2014) and E140 (9 inventions, priority December 2014) transfer the DAP pressure supply to complete vehicle brake systems (brake-by-wire). E138 describes an actuation system in which a DAP as the sole active pressure source supplies both brake circuits simultaneously in forward and reverse strokes. The core architecture dispenses with conventional isolation valves and inlet valves: Claim A1 (EP) protects the basic principle of continuous bidirectional DAP delivery, A12 protects the associated method without isolation valves, and A13 protects the combination with a single master brake cylinder. Five further innovations in the divisional application (E138WO-TA1) supplement the protection with pressure relief mechanisms via a central valve and DAP return stroke, as well as area-switchable pressure relief concepts (CN1 A18, A19). The property rights extend to EP, DE, FR, US, KR, CN, and divisional applications in US and CN.

E138c (patent family E138WO-TA1, 5 inventions) extends protection to area-switchable DAP technology with active pressure reduction. The key feature is the strict dual-circuit assignment of the DAP working chambers: the forward stroke and return stroke (working chambers 10a/10b) are each assigned to a brake circuit and supply it directly — without feed or isolation valves. The floating piston (SK) of the first piston-cylinder unit (main cylinder) separates the brake circuits passively and hydraulically. DE A1 additionally protects active pressure reduction via the DAP — either only in the forward stroke or in both strokes — eliminating the need for classic outlet valves and enabling multiplex operation (MUX) and highly dynamic ABS control. Property rights exist in WO, US (10,759,404), DE (112015003240B4), and CN (107107890B).

E140 expands the brake actuation system to include the principle of bidirectional brake circuit supply with defined check valve topology. The basic system (US A1) combines a pedal-operated master cylinder with an electromechanically driven double-acting hydraulic cylinder (DAP); both working chambers supply the two brake circuits via a hydraulic line each, connected by a fourth hydraulic line with a shift valve. Check valves define the flow paths and ensure fail-operational behavior: if one brake circuit fails, the open VF valve supplies the intact circuit in both directions of travel. Three German divisional applications (E140WODE1/2/3) extend the scope of protection: WODE1 and WODE2 protect designs with an AV2 pressure relief valve, while WODE3 also covers configurations without an actuating device with a broad claim. Property rights exist in WO, US (main application + continuation), CN, and KR.