Longevity was our first requirement. To achieve this
we needed to change the means by which the piston movement was
constrained. A cylinder with large port openings does not satisfactorily
restrain the piston or the piston rings when all these components
are changing in size and shape.
Reliability demanded that the
temperature of the piston be controlled when the engine is operating
at a continuous and high load.
was another prime requirement. The key to efficiency is to reduce
the internal friction and improve the internal gas flow. We therefore
needed to remove load bearing sliding components and create displacement
driven full loop scavenge pattern to reduce fresh charge and exhaust
gas mixing and improve trapping.
was needed to ensure that both the cost of operation and the level
of emissions met the expectations for engines of the future. Keeping
the oil separate from the fuel and from mixing with the induction
air was clearly essential.