Atkinson to Otto cycle (Toyota) - thirts

Can anyone explain how Toyoto's new engines can chage from the Atkinson Cycle to the Otto Cycle?

The only info I can see is that it is does via 'electonics', but how when the valves are controlled by mechanically operated camshafts?

Atkinson to Otto cycle (Toyota) - Wackyracer

Variable valve timing units controlled by the engine ECU.

Atkinson to Otto cycle (Toyota) - skidpan

Probably a similar method is employed to that used changing form Otto to Miller cycle (and back) in the wifes Nissan Note.

www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/hr12d...l

Atkinson to Otto cycle (Toyota) - thirts

Variable valve timing units controlled by the engine ECU.

Yes but how?

The Valves are operated by cams, on a camshaft, that is linked mechanically to the crankshaft via a belt or chain - so how can electronics alter the valve timing as they are set by the crankshaft and mechanical linkages

Atkinson to Otto cycle (Toyota) - Wackyracer

Variable valve timing units controlled by the engine ECU.

Yes but how?

The Valves are operated by cams, on a camshaft, that is linked mechanically to the crankshaft via a belt or chain - so how can electronics alter the valve timing as they are set by the crankshaft and mechanical linkages

The camshafts have special pulleys that are operated hydraulically with engine oil being fed under normal oil pressure to different chambers within these pulleys, it is usually done with electrically operated oil valves. You can see the pulleys in this video of the Ford Ecoboost engine. www.youtube.com/watch?v=IFj5UIZx2cE

 

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