E140 – DAP Universal Pressure
Control System
DAP with bidirectional brake circuit supply, check valve topology, and active pressure reduction. 7 independent inventions · 4 granted patents · US · CN · KR
| Applicant | IPGATE AG, Churerstrasse 160B, 8808 Pfäffikon (CH) |
| Inventors | Heinz Leiber, Dr. Thomas Leiber |
| Priority / Filing Date | December 2, 2014 (DE 10 2014 117 727.4) |
| PCT Application | PCT/EP2015/078339 |
| Technology | DAP universal pressure control system (DAP with bidirectional brake circuit supply, check valve topology, and AV2 pressure reduction) |
| Innovations | 7 independent invention concepts across PCT family (E140WO) and DE divisional (E140DE3) |
DAP Universal Pressure Control
for Build-Up and Release
Patent family E140 describes an actuation system combining a pedal-operated master cylinder with an electromechanically driven double-acting piston (DAP) that supplies both brake circuits bidirectionally — with a specific check valve topology enabling fail-operational behavior and active pressure reduction via an AV2 valve.
The E140 patent family describes an actuation system in which both working chambers of the DAP supply the two brake circuits via dedicated hydraulic lines. A fourth hydraulic line with a switching valve (VF) and a specific check valve (RV) topology enables bidirectional brake circuit supply, active pressure reduction via an AV2 valve, and fail-operational behavior even in the event of a circuit failure. The system also supports controlled pressure reduction directly from the working chambers — bypassing all wheel outlet valves for maximum pressure relief gradients.
The E140 patent family comprises four granted patents: US (US10,369,979 B2 and continuation US11,124,170 B2), CN (CN107107885B), and KR (10-2053714). Four German patent applications (E140DE, DE1, DE2, DE3) extend the protection network; E140DE3 provides independent DE protection for the asymmetrical check valve arrangement.
Development History
The E140 patent family stands at the end of a clearly traceable development line within the IPGATE IP strategy. The starting point was E122 (priority 17.09.2010): an actuating device with a serial design in which the master brake cylinder and the electromotor-driven pressure supply unit were arranged coaxially. This serial three-piston design was rejected due to its large overall length.
The decisive architectural insight in E132 (priority 15.02.2012) was the parallel design — master brake cylinder and pressure supply unit as separate, parallel functional units. This architecture has since become established in modern one-box systems. In E132, the master cylinder controls only the pedal travel simulator; brake pressure is generated by a single-circuit plunger piston.
The motivation for E140 (priority 02.12.2014) arose from two key findings: first, pure MUX pressure control with a single plunger had limitations — sequential wheel valve switching restricts simultaneous pressure build-up on multiple axles. Second, the double-acting piston (DAP) offered two significant advantages over the single-circuit plunger: considerably shorter overall length through pressure generation on both sides, and continuous delivery without dead times during the reverse stroke. E140 combines the proven parallel system design from E132 with a DAP as the pressure supply unit.
7 Independent Inventions in Two Groups
Group 1 (PCT family): 6 innovations covering the VF/RV topology, bidirectional circuit transfer, and AV2 pressure reduction paths. Group 2 (DE divisional E140DE3): independent protection for the asymmetrical check valve arrangement.
Categories, Descriptions & Keywords
All 7 independent invention concepts across two subfamilies. Group 1 (PCT) covers the VF/RV topology, bidirectional circuit transfer, and AV2 pressure reduction. Group 2 (DE3) protects the asymmetrical check valve arrangement independently.
| Invention | Cat. | Description | Keyword |
|---|---|---|---|
| E140WO — PCT Family · US · CN · KR · DE | |||
| E140 A1 US A1 · CN/KR/DE A1 · DE1 A1 |
Device | DAP with VF valve device (4th hydraulic line) between working chambers; RV topology controls flow paths (US A1). CN/KR/DE A1 combine VF + AV2 without RV specification. DE1 A1 is broadest — VF only, without RV and without AV2. Enables bidirectional circuit supply and fail-operational behavior. | VF + RV topology |
| E140 A12/A21 US A12 · CN A21 · KR A13 · DE A12 · DE1 A2 |
Method | DAP delivers in both stroke directions; delivery BK1↔BK2 controlled via switchable connecting line, independent of stroke direction. Enables pressure equalization and cross-circuit supply in the event of circuit failure. Essentially identical in all jurisdictions. | Bidirectional circuit transfer |
| E140 A14 US A14 · DE2 A1 |
Device | AV2 switching valve in 5th hydraulic line of the 2nd/3rd brake circuit connection line to the reservoir; alternative pressure reduction path parallel to wheel outlet valves. DE2 A1 is more broadly formulated with branch point not specified. | AV2 pressure reduction via brake circuit |
| E140 A15 US A15 · DE2 A2/A3/A4 |
Device | AV2 switching valve in 5th hydraulic line directly from working chamber(s) to reservoir; maximum bypass of all wheel valves; highest achievable pressure reduction gradients. DE2 A2/A3/A4 specify the direct working chamber path with additional process claims. | AV2 pressure reduction direct from working chamber |
| E140US1 A1 | Device | 4th hydraulic line leads directly from 2nd working chamber (30b) to the reservoir — without RV topology. Return stroke with AV2 open: pressure medium from brake circuits flows into 1st working chamber for finely metered pressure reduction via DAP volume control. Independent US continuation claim. | Direct working chamber reservoir path |
| E140US1 A15 | Method | Method: Piston in forward position (step a); return stroke with open AV2 (step b) → pressure medium from brake circuits flows into 1st working chamber for precisely metered pressure reduction. Independent method protection of the US continuation application. | Volume-based pressure reduction |
| E140DE3 — DE Divisional · Asymmetrical RV Arrangement | |||
| E140DE3 A1/A5 | Device | Working chambers directly connected to one brake circuit each; check valve (RV) in the 4th hydraulic line prevents uncontrolled volume flow (hydraulic short circuit) between working chambers. Key feature: asymmetrical RV arrangement — RV1 BEFORE, RV2 AFTER the junction of the 4th line. Independent DE protection concept not included in PCT claims. | RV short-circuit protection |
Jurisdictions & Status
All members of the E140 patent family as of February 2026. Four rights are granted (US, US continuation, CN, KR); DE applications are pending.
| File No. | Country | Status | Type | Application No. | Filed | Grant No. | Granted |
|---|---|---|---|---|---|---|---|
| E140WOUS | US | Granted | Patent | 15/532,731 | Dec. 2, 2015 | US10,369,979 B2 | Aug. 6, 2019 |
| E140WOUS1 | US | Granted | Continuation | 16/507,748 | Dec. 2, 2015 | US11,124,170 B2 | – |
| E140WOCN | CN | Granted | Patent | 201580065369.3 | Dec. 2, 2015 | CN107107885B | May 11, 2021 |
| E140WOKR | KR | Granted | Patent | 10-2017-7018183 | Dec. 2, 2015 | 10-2053714 | Dec. 3, 2019 |
| E140DE | DE | Pending | Patent | 102014117727.4 | Dec. 2, 2014 | – | – |
| E140DE1 | DE | Pending | Divisional | – | – | – | – |
| E140DE2 | DE | Pending | Divisional | – | – | – | – |
| E140DE3 | DE | Pending | Divisional | – | – | – | – |
