E148 – Dual-Stroke Hydraulic Unit
with Bidirectional Volume Pressure Control
Pressure generation device with electrically driven double-acting piston (DAP), two independent working chambers, bidirectional piston stroke control via pressure-volume characteristics, and simultaneous pressure build-up and reduction across dual hydraulic circuits. 5 invention complexes · 12 granted rights · EP · US · JP · KR · CN · IN
| Applicant | IPGATE AG, Churerstraße 160a, 8808 Pfäffikon (CH) |
| Inventors | Heinz Leiber, Dr. Thomas Leiber |
| Priority / Filing Date | March 21, 2016 (DE 10 2016 105 232.9) · PCT: March 16, 2016 |
| PCT Application | PCT/EP2016/055703 (WO 2016/150546 A1) |
| Technology | Electrically driven double-acting piston (DAP) with two working chambers — bidirectional pressure volume control; simultaneous pressure build-up in one circuit and reduction in the other via piston stroke and changeover valves |
| Innovations | 5 invention complexes (3× device + 2× method) · 6 property rights (EP, EP1, US, US1, CN, CN1) |
Double-Acting Piston with
Bidirectional Volume Pressure Control
Patent family E148 describes a pressure generation device with an electrically driven double-acting piston (DAP) that forms two working chambers and can independently build up and release pressure in two separate hydraulic circuits — simultaneously, in opposite directions.
The central innovation is a piston-cylinder unit with a double-acting piston defining two working chambers (3a, 3b). Via controlled changeover valves (PD1, PD2), pressure in one or both circuits can be released into a reservoir through the working chambers, or directly via outlet valves (AVi). An optional connecting line (H5) with a switching valve (ShV) can couple the two working chambers for pressure equalization or volume-based cross-circuit control.
Pressure build-up is governed by piston stroke control based on stored pressure-volume (pV) characteristics per circuit. The bidirectional architecture enables simultaneous pressure build-up in one circuit while the second working chamber releases pressure in the other — a degree of freedom unavailable in single-stroke or gear-pump based systems. The E148 family extends over 6 property rights (EP, EP1, US, US1, CN, CN1) with 12 granted rights across 10 jurisdictions.
From Valve-Side to Supply-Side: E147 → E148
While the preceding E147 family introduced novel valve-side architecture — inverting the inlet valve wiring to enable check-valve-free, fault-tolerant pressure control — E148 addresses the pressure supply side directly. Together, the two families form a comprehensive system: E147 governs how pressure is distributed and maintained at the wheel brakes; E148 governs how pressure is generated and controlled at source.
In brake-by-wire systems for autonomous driving, the demands for simultaneous, independent pressure control across multiple circuits are increasing sharply — for functions such as torque vectoring, brake-steer, and wheel-selective regenerative braking. A single-stroke pump cannot satisfy these requirements without significant valve complexity.
E148 thus complements E147: where E147 controls how valves distribute pressure at the wheel, E148 controls how the DAP supplies pressure at the source. Both patent families together enable a complete, check-valve-free, simultaneously controllable dual-circuit brake-by-wire architecture.
Five Invention Complexes
The 5 invention complexes of E148 cover the core DAP device architecture, the volume-control method via pV characteristics, a simplified dual-chamber variant, an adaptive dual-circuit control method, and simultaneous dual-circuit pressure operation.
Invention Complexes, Descriptions & Keywords
5 invention complexes across 6 property rights (EP, EP1, US, US1, CN, CN1). Covers device and method claims for DAP-based pressure supply in dual-circuit brake-by-wire systems.
| Complex · References | Cat. | Description | Keyword |
|---|---|---|---|
| EK 1 – DAP Supply Unit EP 3271228 B1 (A1) · US 11,097,708 B2 (A1) · CN 107438543 B (A1) · CN 114368370 B (A1) · US 20210339727 A1 (A1) |
Device | Pressure generation device with double-acting piston (1), two working chambers (3a, 3b) and two hydraulic circuits (K1, K2). Changeover valves (PD1, PD2) for pressure relief via working chambers; optional outlet valves (AVi) for direct pressure relief; connecting line (H5) with switching valve (ShV) for coupling the working chambers. | DAP · Two chambers · Changeover valves · ShV coupling |
| EK 2 – Volume Control Method EP 3271228 B1 (A15) · US 11,097,708 B2 (A22) · CN 107438543 B (A32) · CN 114368370 B (A25) |
Method | Piston stroke control based on pressure-volume characteristic curves. Pressure reduction via forward/return stroke and/or outlet valves, while simultaneously the second working chamber builds pressure in the other circuit. Bidirectional simultaneous pressure build-up/reduction in two circuits via a single piston motion. | pV characteristic · Piston stroke · Simultaneous build-up/reduction |
| EK 3 – Simplified Device EP 4129783 B1 (A1) |
Device | Simplified variant of the DAP device with switching valves (PD1, PD2) in second hydraulic lines (H1, H2) for connecting working chambers to the reservoir. Focus on targeted pressure relief architecture without full bidirectional stroke complexity. | Simplified DAP · Switch valves · Targeted relief |
| EK 4 – Adaptive Control Method EP 4129783 B1 (A10) |
Method | Method with piston stroke control based on pV characteristic curves; pressure reduction via piston stroke and/or outlet valves with simultaneous pressure supply to the second circuit. Adaptive pressure targets per circuit within a single stroke sequence. | Adaptive control · pV stroke · Simultaneous supply |
| EK 5 – Simultaneous Operation US 11,097,708 B2 (A36) · CN 107438543 B (A2) |
Device | Pressure generation device for simultaneous pressure change in both brake circuits. Double-acting piston with special valve control for simultaneous pressure build-up/reduction in K1 and K2 without sequential circuit switching — fully parallel, independent pressure management in both hydraulic circuits. | Simultaneous K1+K2 · No sequential switching · Parallel control |
Jurisdictions & Status
All members of the E148 patent family as of February 2026. 12 granted rights across 10 jurisdictions; 2 applications pending (US divisional, KR main).
| File No. | Country | Status | Type | Registration No. | Filed | Grant No. | Granted |
|---|---|---|---|---|---|---|---|
| E148WOEP | EP | Granted | Patent | 16711220.0 | Mar. 16, 2016 | EP 3271228 B1 | Jul. 13, 2022 |
| E148WOEPDE | DE | Granted | Patent (via EP) | 502016015066.4 | Mar. 16, 2016 | EP 3271228 B1 | Jul. 13, 2022 |
| E148WOEPFR | FR | Granted | Patent (via EP) | 16711220.0 | Mar. 16, 2016 | EP 3271228 B1 | Jul. 13, 2022 |
| E148WOEPGB | GB | Granted | Patent (via EP) | 16711220.0 | Mar. 16, 2016 | EP 3271228 B1 | Jul. 13, 2022 |
| E148WOEPNL | NL | Granted | Patent (via EP) | 16711220.0 | Mar. 16, 2016 | EP 3271228 B1 | Jul. 13, 2022 |
| E148WOUS | US | Granted | Patent | 15/558,385 | Mar. 16, 2016 | US 11,097,708 B2 | Aug. 24, 2021 |
| E148WOJP | JP | Granted | Patent | 2017-548861 | Mar. 16, 2016 | JP 7264591 B2 | Apr. 17, 2023 |
| E148WOKR | KR | Pending | Patent | 10-2017-7029740 | Mar. 16, 2016 | — | — |
| E148WOCN | CN | Granted | Patent | 201680016524.7 | Mar. 16, 2016 | CN 107438543 B | Oct. 29, 2021 |
| E148WOIN | IN | Granted | Patent | 201717035154 | Mar. 16, 2016 | IN 482888 B | Dec. 14, 2023 |
| E148WOEP1 | EP | Granted | Divisional | 22184243.8 | Mar. 16, 2016 | EP 4129783 B1 | May 22, 2024 |
| E148WOUS1 | US | Pending | Divisional | 17/378,201 | Mar. 16, 2016 | — | — |
| E148WOKR1 | KR | Granted | Divisional | 10-2023-7039045 | Mar. 16, 2016 | KR 102714967 B1 | Oct. 2, 2024 |
| E148WOCN1 | CN | Granted | Divisional | 202111170671.9 | Mar. 16, 2016 | CN 114368370 B | Apr. 23, 2024 |
