Engine applications for PEM/SPE oxyhydrogen

Short answer

Short answer: PEM/SPE oxyhydrogen systems are used in diesel engines, generators, furnaces and industrial engines. Integration depends on load profile and combustion characteristics.

Heavy-duty diesel engines

Road transport and off-highway diesel engines are the most common application. Gas is introduced into the intake downstream of the mass-airflow sensor, with no change to fuel system or engine control calibration. Unit size is selected by displacement, and duty cycles with sustained load give more consistent conditions than short stop-start work. Displacement-based selection is set out on the industrial applications index.

Diesel generator sets

Gensets run at fixed speed under a defined electrical load, which makes them the easiest case to instrument: fuel flow, load and exhaust measurements can all be logged at a steady operating point. Prime-power sets running long hours provide more measurement data than standby sets.

Industrial furnaces and burners

In furnace and burner applications the gas is introduced to the combustion air stream rather than to an engine intake. Combustion is continuous rather than cyclic, so the relevant measures are stack composition, flue temperature and specific fuel consumption per unit of output rather than crank-angle-resolved heat release.

Fixed industrial engines

Pumps, compressors and other fixed engine-driven plant sit between the genset and mobile cases: a stable duty cycle with a permanent power supply for the electrolyser. Our own industrial deployments and audited results are described in the industrial oxyhydrogen case studies.

Marine engines

Marine propulsion and auxiliary engines operate at high sustained load, which suits continuous gas generation. The absence of a caustic electrolyte is a practical consideration in a vessel environment, since a pure-water circuit carries no corrosive liquid. Installation must follow the vessel's own electrical and ventilation requirements.

What determines integration

Three variables govern every case: engine displacement or thermal input, load profile over time, and available electrical supply for the electrolyser. Effects reported in the published literature are conditional on those variables — see the 2026 Scientific Reports HHO study review and hydrogen combustion enhancement principles.