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A partnership of Research and Industry entities has developed a fully working hybrid electric vehicle equipped with a 15 kW IC engine fuelled with liquid ammonia as range extender of the lithium batteries pack on board. All the vehicle powertrain, i.e., the IC engine, the electric generator coupled with the engine, the electric motor, the electronics, etc., has been studied and designed. Regarding the IC engine, as known, ammonia combustion is characterized by a high activation energy and a low flame velocity, therefore a small amount of hydrogen is requested as igniter and combustion promoter. The necessary amount of hydrogen is coming from the thermal decomposition of the same ammonia by cracking it at approximately 400°C inside a special catalyst (purposely realized within the project) heated by the engine exhaust gasses. The Nitrogen and Hydrogen mixture coming from the cracker is introduced, by an indirect injection, into the intake manifold together with the ammonia.

Storing hydrogen is one of the major problems concerning its utilization on board vehicles. Today hydrogen can be compressed and stored at 200 or 350 bar (it is foreseen that in a near future storage pressure will reach 700 bar, according to new expected regulations and using tanks in composite materials) or cryogenically liquefied. An alternative solution is storing hydrogen in the form of ammonia that is liquid at roughly 9 bar at environmental temperature and therefore involves relatively small masses and volumes and requires light and low-cost tanks. Moreover, ammonia contains almost 18% hydrogen by mass and, by volume, liquid ammonia contains 1.7 times as much hydrogen as liquid hydrogen. It is well known that ammonia can be burned directly in I.C. engines, however a combustion promoter is necessary to support combustion especially in the case of high-speed S.I. engines.