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Fast and flexible etavalve actuators are the heart of this storing concept - making the contained heat engine both: fully reversible and highly efficient.

Fluctuating electricity inputs (like from green sources) can be transformed to 24/7 on demand electricity.

Optionally the etastore concept also allows to supply high temperature industrial heat and cold.



Trees store CO2.

However waste wood from forests or wood industries returns the captured CO2 back to atmosphere when rottening or being burned.

Charcoal burning transforms the waste wood into storable carbon instead. Charcoal is chemically stable for some hundred years and is used to improve agriculture soils.

The etacapture project allows to win electricity from charcoal burning by the use of the etasave engine.


The etasave engine concept allows to use residual heat from various external sources within a wide range of temperatures to produce electricity at optimum efficiency, thus allowing high returns of investment.

Heart of the engine are the fast and flexible etavalve actuators.




etacapture and etasave
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etavalve actuators

The electrohydraulic actuators are capable to move gas exchange valves of 100 mm diameter within

10 milliseconds.

First test units were delivered in 2021 for a gas expander machine.

Highly dynamic and low-loss gas flow control is the core requirement for various innovative heat engines with external heat supply.


etavalve actuators


... is the outcome of a common development with Swiss Federal Labatories for Material Sience and Technology (Empa).


The prototype system on a typical passenger car engine is running on engine coolant and working most reliably due to its manageable complexitiy.

Flexible engine control will be a key factor for future internal combustion engine applications or where electric drives are not applicable.


. . .   skips the cams with its given lift-timing linkage

to have full flexibility.

. . .   confine valve lifts to speed and needs 

to pull less energy from the crank.

. . .   uses smart electro-hydraulic systems

to recover energy input.

. . .   builds on existing valve-spring constructions

to keep valve closing reliable.

. . .   uses near standard parts

       to be cost competitive.

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