The all - new lightweight, downsized 2.0 - litre Si4 petrol engine employs the latest generation of high pressure direct - injection technology, together with low - inertia turbocharging and twin independent variable valve timing, to create
an exceptionally efficient combustion system.
Since the volumetric energy density of ammonia is three times that of liquid hydrogen, and ammonia
combustion can be
exceptionally efficient (about the same as burning diesel fuel in turbodiesels), it may be true that a hydrogen economy based upon OTEC and ammonia may be close at hand.