E136 – Adaptive Double-Acting
Piston (DAP) Pressure Supply
Adaptive valve-controlled double-acting piston pressure supply for electrohydraulic brake systems. 11 independent inventions · 5 granted patents · DE · US · CN
| Applicant | IPGATE AG, Churerstrasse 160a, 8808 Pfaeffikon (CH) |
| Inventors | Heinz Leiber, Dr. Thomas Leiber |
| Priority / Filing Date | September 16, 2013 (DE102013110188) October 30, 2013 (DE102013111974) February 26, 2014 (DE102014102536) |
| PCT Application | PCT/EP2014/069650 |
| Technology | Adaptive double-acting piston (DAP) pressure supply |
| Innovations | 11 independent invention concepts (6 divisional + 5 parent), 15 independent claims |
Adaptive Double-Acting Piston for IBS2
Patent family E136 describes a braking device with an electrically driven double-acting piston (DAP) that feeds pressure medium into brake circuits in both directions of movement — enabling uninterrupted pressure build-up, adaptive area switching, and significant motor torque reduction.
The E136 patent family describes a braking device and a method for operating it, in which an electrically driven double-acting piston (DAP) feeds pressure medium into the brake circuits in a controlled manner in both directions of movement (forward stroke and return stroke). The core innovation lies in the adaptive valve-controlled coupling of the pressure chambers, which enables situational adjustment of the effective piston area and thus ensures both high delivery volume and reduced motor torque in the high-pressure range.
The E136 patent family comprises 5 granted patents in the jurisdictions DE, US, and CN. The invention forms a central technological component of the second generation of IBS (IP portfolio B1) and addresses in particular the requirements of vehicle dynamics systems for continuous, uninterrupted pressure supply.
Development History
The development of the double-stroke piston concept for vehicle brakes began in 2014 as part of IPGATE's second generation of integrated braking systems (IBS 2). The driving question was how to provide sufficient pressure medium volume for modern braking systems, especially for low-friction brakes, SUVs/vans with high volume requirements, and fading situations without compromising fault tolerance and fallback level function.
The earlier solutions (e.g., storage chamber concepts from DE 10 2011 009059, DE 10 2011 111368) had in common that they either placed high demands on valve tightness, interrupted pressure build-up during long braking operations, or subjected the spindle and ball screw drive to additional axial forces. The basic idea behind the E136 invention — the use of a double-acting piston (DAP) that delivers controlled pressure medium to the brake circuits during both the forward and return strokes — fundamentally solves the problem of pressure interruption: Since both piston strokes are used for pressure supply, theoretically unlimited volume delivery with high dynamics (switching time <10 ms) is possible without interrupting the pressure build-up.
The adaptive valve-controlled coupling of the two pressure chambers via solenoid valves enables the functional principle of a two-stage hydraulic transmission: In the low-pressure range, a large effective piston area provides high volume, while in the high-pressure range, the chamber connection switches to a smaller effective area, which significantly reduces the required motor torque. This results in a reduction in overall length of approx. 48 mm and a reduction in master cylinder stroke of up to 50%.
11 Independent Inventions
6 concepts from divisional applications (E136WOUSTA, E136WOCNTA, E136WODE) and 5 from parent applications (E136WOUS, E136WOCN).
Categories, Descriptions & Keywords
Overview of all 11 independent invention concepts. The divisional applications (WOUSTA, WOCNTA, WODE) cover the core adaptive chamber coupling; parent applications (WOUS, WOCN) cover further design embodiments.
| Invention | Cat. | Description | Keyword |
|---|---|---|---|
| E136 A1 US div., DE |
Device | Actuating device for vehicle brakes with an electrically driven double-stroke piston (DAP) that feeds pressure medium into the brake circuits during the forward and return strokes. Different effective piston areas; solenoid valve coupling of chambers allows switching to smaller effective area in high-pressure range → motor torque reduction. | DHK with valve-controlled chamber coupling |
| E136 A30 (US) / A11 (DE) | Method | Method for operating a brake device with continuous bidirectional pressure delivery through the DAP. Adaptive chamber switching by ECU: effective areas are coupled situationally by valve connection to reduce piston force/motor torque. No delivery stroke lost; uninterrupted pressure build-up. | Bidirectional delivery, adaptive switching |
| E136 A38 US div. |
Device | Brake device with 3/2-way solenoid valve and downstream check valve in the hydraulic line between the DAP annular space and the brake circuit lines. Replaces two separate valves. Length reduction ~48 mm; master cylinder stroke reduction up to 50%. | 3/2-way valve brake actuator |
| E136 A50 US div. |
Method | Method for actuating a vehicle brake: DAP alternately delivers from chamber 1 (forward) and chamber 2 (return); at least one valve temporarily connects chambers to vary effective piston area. Basis for highly efficient EHB actuators. | Bidirectional delivery, temporary chamber connection |
| E136 A1 CN div. |
Device | Broad device application: Control device with DAP delivering pressure to brake circuits in both piston movement directions; chambers connectable via at least one valve. Covers 4 applications: motor torque reduction, circuit separation (fail-operational L4/5), controlled pressure reduction (ABS, HLF), adaptive area switching. | DAP brake device with adaptive operating modes |
| E136 A12 CN div. |
Method | ECU-controlled method with DAP for bidirectional pressure delivery. 4 operating modes; switching time <10 ms; fully diagnosable through pressure-volume characteristic curve evaluation. | ECU-controlled bidirectional method |
| E136 A1 US parent |
Device | Actuating device with DAP and hydraulically driven secondary piston transmitting pressure to a second pressure chamber and brake circuit. Supply of two brake circuits from a single cylinder unit without mechanical coupling. | DAP with secondary piston |
| E136 A8 US parent |
Device | Actuating device with DAP and mechanical clutch in fallback level for separating drive and piston. Ensures driver braking capability in electrical failure (F-BbW). | DAP with fallback coupling |
| E136 A13 US parent |
Device | Actuating device with free play between brake pedal/plunger and spindle via flex rod or coupling. Decoupling of pedal feel and actuator movement. | DAP with free travel / bending rod |
| E136 A41 CN parent |
Device | The double-acting piston itself as an independent object of protection for hydraulic actuators — unique CN-specific protection direction with no equivalent in other jurisdictions. | Double-acting piston |
| E136 A43 / A60 CN parent |
Method / Device | A43: Method for operating the brake device with ECU-controlled DAP for bidirectional delivery and adaptive chamber switching. A60: Brake device implementing method A43. Independent CN device-method pairing. | DAP operating method CN |
Jurisdictions & Status
All members of the E136 patent family as of February 2026. All five rights are granted.
| File No. | Country | Status | Type | Application No. | Filed | Grant No. | Granted |
|---|---|---|---|---|---|---|---|
| E136WODE | DE | Granted | Patent | 112014004233.1 | Sep. 16, 2014 | DE112014004233B4 | Mar. 8, 2023 |
| E136WOUSTA | US | Granted | Patent (divisional) | 16/174,437 | Sep. 16, 2014 | US11,104,317 B2 | Aug. 31, 2021 |
| E136WOCNTA | CN | Granted | Patent (divisional) | 201910758513.1 | Sep. 16, 2014 | CN110576840B | Feb. 1, 2022 |
| E136WOUS | US | Granted | Patent (parent) | 15/022,394 | Sep. 16, 2014 | US10,112,592 B2 | Oct. 30, 2018 |
| E136WOCN | CN | Granted | Patent (parent) | CN201480051135.9 | Sep. 16, 2014 | CN105636842B | approx. 2018 |
