DIY_EFI Digest V4 #580

[Stuart Hastings]

> > Speaking as a potential customer, the extra belt and air compressor
> > used on the Orbital design look like additional parts to break.
> 
> Of course. But a belt driven air compressor is not exactly rocket science...
> 
> > The Ficht design has none of these parts.
> 
> The Ficht has a whole lot of other parts to break. (And it seems to be doing  
> so with gusto...:))

Hmmm. Oddball injectors, computer to drive them, special alternator,
and an oil injector in the crankcase... I guess you have better
sources than I do, but I had understood that most (catastrophic) Ficht
failures were related to internal engine parts, like pistons, rings,
and cylinders. Stuff that was supposed to be well-debugged by now :-) .

...
> True. They could have moved the precompression out of the crank case, using  
> a conventional "wet" crank case, and a screw compressor instead. That would  
> have given more efficient scavenging, and gotten rid of all oil in emissions.  
...

I doubt the marine engine manufacturers would fit a compressor unless
required by smog regulations. It adds weight, complexity, and cost.
But I personally would consider owning such an engine.

> > More specifically, EPA is interested only in *air* pollution from
> > marine engines. When they mandated oxygenated fuel, they indirectly
> > required California fuel to incorporate MTBE, and nobody realized it
> > would contaminate the *water*.
> 
> This may be true. I read somewhere that it is doubtful that a significant  
> amount unburnt gasoline passes into the environment because of the high  
> temperature of the exhaust gases.

It has been definitively shown here in California that most of the
MTBE found in surface water (lakes, reservoirs) came from non-DFI
two-cycle engines.

Here in the Silicon Valley, the local water authority permits
powerboats on three of our ten drinking water reservoirs. One of these
is open to Personal Water Craft (e.g. Jetskis(tm)) at the beginning of
every season, and promptly closed to them after the MTBE concentration
rises above a certain threshold. PWC dealers in Northern California
have mostly been driven out of business. My four-cycle boat is still
permitted on all three reservoirs.

When DFI manufacturers claim 25-30% improvements in fuel economy,
they're talking about raw fuel that was formerly blown out the
exhaust. This is a settled issue.

> Since I'm not American, I won't claim to know how the EPA thinks or
> works, though.

The U.S. E.P.A. is a source of wonderment for us Americans, too :-) .

> > Hello, EPA, most marine engines exhaust
> > *underwater*, even if most of their smog immediately bubbles to the
> > surface!
> 
> That can easily be fixed with a holesaw, if you're worried. :)

I'm not worried, because I insisted on four-cycle power when I bought
my boat. I'm not a "greenie," but spitting oil (and/or gasoline) into
the water dismays me, in spite of all genuine advantages of two-stroke
engines on a boat.

Most marine engines (in the U.S.) exhaust underwater because it's
essentially required by the U.S. Coast Guard for basic
safety. Boat-engine exhaust is typically mixed with water shortly
after it leaves the engine. Most sterndrives (marinized car engines)
have many rubber parts in the exhaust just downstream of the water
port; if the water supply fails, the rubber parts promptly melt.

If nothing in the boat is hot enough to start a fire, there should be
fewer boat fires. Nobody was thinking about ecology when these rules
were established.

stuart hastings