Dual-fuel engine for digester gas combustion, photo: Schnell
Dual-fuel engine for digester gas combustion, photo: Schnell

Dual-Fuel Engines

The working principle of dual-fuel or pilot ignition engines is derived from diesel engines. Both are are self-igniting engines regarding their constructional design.


Due to the high antiknock properties of digester gas dual fuel engines can compress the air/gas mixture to a very high level. 

Injection of a small amount of ignition oil fuels the ignition in the combustion chamber. Normally biodiesel or vegetable oil serve as ignition oil.

Optimized dual fuel engines can operate with as little as 2% of pilot ignition oil, whereas older engines need up to 10%.

Basically any diesel engine can be converted into a dual fuel engine, in particular with injection systems such as unit injector or common rail. Electronically controlled, these systems are able to adjust to changing biogas qualities.

With the higher compression ratio the dual fuel engine, like the diesel engine, operates, due to physical reasons, at a high efficiency.

For more information please click ยป dual-fuel engine

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