“(Keronite is a) new low cost
aluminium coating technique, in this
case specifically applied to pistons
but also capable of application in other
areas of engine design such as exhaust
ports and valve seats. When applied
to diesel combustion bowls a direct
efficiency improvement is obtained due
to reduced heat loss to walls. Although
this is not a large benefit, it also
allows higher temperatures to be tolerated
during combustion and expansion. This
benefit will allow for specific performance
increases and hence provide a downsizing
effect. It has been shown that downsizing
in diesel engines can produce up to
10% improvements in fuel economy. The
application of the (Keronite) coating
technique to diesel piston ring grooves
will, at least, allow a cost and weight
reduction on the current steel insert
ring groove technology. This will have
positive knock-on effects in other areas
of engine design providing the benefits
above of those specifically associated
with the pistons.
When considering the
application of this technique to gasoline
engines it is clear that it is a key
enabler to downsizing. It is common
in high specific output gasoline engines
to have cylinder pressure approaching
that of current production diesel engines.
In this case it is normal to hard anodise
the tip ring groove to provide a suitable
level of durability. This new (Keronite)
technique has environmental advantages
over the hard anodising process. Various
studies have shown the downsizing to
provide between 15 and 20% fuel economy
benefit in real production vehicle applications.” |