A Hybrid Vehicle Powered by Hydrogen and Ammonia 2012-32-0085
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
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.
Ammonia is stored on board inside a tank very similar to the LPG
gas tanks, being ammonia maintained in a liquid state at
approximately 0.9 MPa. The pipelines had to be resistant to the
chemical aggression of ammonia and special part had been used. The
combustion of ammonia has as reaction products only water and
nitrogen oxides, being these last ones easily removable by means of
a catalytic system (SCR) helped by the presence of ammonia.
A first campaign of engine testing has been carried out giving
great results, considering that an optimization phase has to come,
confirming that the amount of hydrogen produced by the catalyst
(roughly 1,3 m₃/h) is enough for a satisfactory engine running.
Road tests for the entire vehicle are actually on course.
However, the use of ammonia for the propulsion of motor vehicles
introduces some issues on safety, because of the chemical-physical
characteristics of the substance. Ammonia is moreover a toxic gas
whose ways of penetration in the human organism can be: inhalation,
ingestion and contact. This is why a complete work package of the
project has been given to safety, building up a sensors system in
order to detect presence of ammonia in the local of the engine and
in the exhaust system. This kind of vehicles for transport with
series hybrid propulsion (vehicle electrical worker fed from
batteries charged by an ammonia generator) would allow to have ZEV
("Zero Emission Vehicle") and stationary generation
devices fuelled with ammonia turn out interesting also for the
storage of energy coming from renewable sources (wind,
photovoltaic, etc.) which actually use grid as storage system.
Giuseppe Pozzana, Neri Bonfanti, Stefano Frigo, Nicolò Doveri, Paolo Dario, Virgilio Mattoli, Marina Ragnoli
Pont-Tech scrl, Pontedera Italy, Energia e Sistemi Univ. Pisa, Italy, EDI Progetti&Sviluppo, Pontedera, Italy, Scuola Superiore Sant'Anna, Italy, Center for Micro-BioRobotics, IIT, Italy, Acta Energy spa, Crespina, Italy
2012 Small Engine Technology Conference & Exhibition