Engineers have developed an electro-hydraulic valve system that saves approximately 20% fuel by optimizing gas exchange in a spark ignition engine.
In an innovative system invented by scientists at the Swiss Federal Laboratory for Materials Science and Technology, the valves are hydraulically actuated and controlled electrically via an electromagnetic coil..
When current is applied, a specially designed hydraulic valve opens, allowing the hydraulic fluid to open the gas exchange valve to the desired extent against the spring.
When the voltage is removed, the gas exchange valve is closed again by the spring force and feeds most of the hydraulic power required to open back into the hydraulic system..
This technology reduces energy costs over a wide operating range compared to camshaft systems. Tests have shown that, thanks to optimized gas exchange, a spark ignition engine uses about 20% less fuel than conventional valve control using a throttle in combination with camshafts in the low load range typical of passenger cars.
In addition, the new system allows you to control operating parameters, opening and closing times, as well as valve lift for each cylinder separately, without restrictions. This means that any operating state of the engine can be changed from cycle to cycle. For example, through intelligent load management, by monitoring the amount of residual gas in a cylinder or by shutting down unnecessary cylinders.
This makes it easy to adapt the engine to new fuels or alternative fuel concentrations. And no expensive components or complex sensors are required to control the valves..
Another feature of the Swiss system is the choice of hydraulic fluid: instead of conventional oil, you can use a water-glycol mixture, that is, engine cooling water.
The new valve system was tested on a passenger car internal combustion engine running on natural gas and on a VW 1.4l TSI gasoline engine. The tests began last year, and the developed control system has flawlessly survived many millions of work cycles..
Scientists are already in talks with automakers to transfer this technology into production..
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We also previously reported on development of a plasma nanopulse ignition system, which increases engine efficiency by 10-20%.
text: Ilya Bauer photo: EMPA