I am not so sure we will see them in widespread use anytime soon in marine
The purpose of all this development of diesel fuel
systems has been to make diesel
engines in cars perform more like gasoline engines. Especially, to increase the RPM
range and power to weight ratio.
The new diesel cars, with very high pressure small diameter turbos, and common rail injection systems, are amazing. In some cases (BMW) they are better
than gasoline engines, much more torque with the same power.
But the design values for marine
use are completely different
. We care nothing about RPM
range and very little about power to weight ratios. A diesel only needs precise fuel
metering when it starts to push the envelope in terms of power out of a given quantity of air. We are almost never in that situation; at cruising speed and RPM we are only putting a little fuel into the compressed air mass, and a simple mechanical injector will do just as good a job as a common rail.
My own propulsion engine
, a Yanmar
, is turbocharged and intercooled, and I question the sense of having a turbocharged engine
in a sailboat. What is the purpose of all of this complexity (and so many things to break)? It allowed the makers to produce a wider range of engines on a single
block, for one. It allowed them to get a more powerful (and expensive) engine out of a smaller and cheaper block.
But from my point of view, the only advantage is that it is somewhat more efficient, somewhat lighter, and somewhat quieter, than a natural aspirated engine would be. Is it worth the greater risk of breakdowns? The greater risk of something breaking which I can't fix? Or can't get fixed?
I like the idea of common rail engines in our boats even less.