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Subject: TWL: Re: Re: Boats, cars and electronic...
From: Mike Schooley (schooley@XXX.XXX)
Date: Wed Jan 23 2002 - 22:36:18 EST
Danny Meyer wrote, "Lightening strike. Ouch <snip> Anyway, a consideration."
If I still worked for Boeing, I'd ask the EMI/EMC (electro-magnetic
interference/ electro-magnetic compatibility) guys. Airplanes are hit by
lightning much more often than Airlines want you to know with no ill effect.
I know it can be done and the first step is a good lightning protection
system. The second step is a good ground path (can you say conductive
hull:-).
"Also I was wondering, what diesels with electronic injection are we talking
about? All the ones I have looked at in my size range are still mechanical
injection. Of course I am not trying to plane my 20 ton full displacement
boat, so I am admittedly looking at smaller engines . . . "
I found a good review on electronically controlled diesel engines at Power
and Motoryatchs
http://powerandmotoryacht.about.com/library/weekly/aa011201a.htm. The EPA
requirements started of large/commercial engines and they are working the
power curve and to recreational boats.
For those of us living in the US the source of environmental regulations is
the EPA http://www.epa.gov/otaq/marine.htm outside the US the requirements
are set by the IMO. The proposed requirements specific to new non-road
engines are in http://www.epa.gov/otaq/regs/nonroad/proposal/f01026.pdf the
requirements for recreational marine diesel engines are on page 5. The FAQ
for new recreational marine diesels is at
http://www.epa.gov/otaq/regs/nonroad/proposal/f01029.htm.
The EPA requirements set levels of emissions and allow the engine
manufacturers to determine how they will meet them. Manufacturers may meet
them with electronic controls or other improvements.
"A diesel used to drive a large water pump for instance . . . electronic
injection would be pointless complexity and expense, as the RPM is constant
and timing variations (the real value to electronic injection) would be
unnecessary.<snip>"
Actually even a constant speed engine can benefit from electronic controls
since they can adjust for variations in atmospheric conditions. Basically,
if you design an engine to operate in the hottest conditions that it might
ever experience, it will operate off-optimum almost everywhere and almost
all the time. Monitoring aftercooler temperature and adjusting cooling rates
allows higher turbo boost pressures, increasing power and fuel efficiency.
If you can tell the engine designed the exact speed, load and operating
conditions including temperature and humidity, that the engine will operate
in, then I'd agree. But in the real world the electronically controlled
engine will provide more power, higher efficiency and better durability than
a mechanically controlled engine.
"Seems to me that it would be of limited value to a boat engine also, as
they are typically run for long periods at a constant load/rpm. The
mechanical injection curves are remarkably efficient, it is in highly
varying loads/RPM's where the electronic injection really shines . . . and
the best effect is during the power change itself."
Gee how long ago was it that we were discussing the black rain?
"As for fault monitoring . . . Oil pressure, water temp, exhaust temp . . .
what else would you monitor on a mechanical engine? Now if it had
electronics, then I can think of a host of things to monitor, but they would
be concerning the electronic controls and peripherals themselves . . ."
Sounds like an electrical engineers comments to me. Here are some excerpts
from the Power and Motor Yacht reference listed above.
"Cummins' newest engine, the QSM11, is its first to offer an electronically
controlled fuel system. A sophisticated computer monitors rpm, coolant
temperature, oil pressure, intake manifold temperature, engine load,
turbocharger boost pressure, oil temperature, fuel-use rate, ambient
temperature and pressure, percent throttle, total fuel used, total engine
hours, trip fuel used, trip hours, and selected fault codes."
"Caterpillar has two separate monitoring systems available, both offering
the same basic features. The Marine Power Display (MPD) is designed for
smaller engines, while the Cat Engine Vision (EVD) system is geared towards
bigger diesels. The MPD allows the operator to view rpm, coolant
temperature, fuel rate, oil pressure, fuel pressure, fuel temperature,
battery voltage, transmission pressure, and more, similar to the Cummins'
system. It receives data through an SAE J1939 or J1587 ATA data link, a
twisted wire pair or cable that <snip>"
In addition Advanced Engine Technologies (AET) http://www.aet.ca/ in Canada
has an ingenious system of monitoring each cylinders performance by
measuring the angular acceleration of the crank shaft. What the electronics
can measure is only limited by the sensors that are available and their cost
to benefit ratio. Most sensors today are integrated chips and the cost of
integrated chips is declining faster than the Argentinean peso.
"I am not against electronic controls/injection. I think they are the best
thing to happen to the auto world, and I think the OTR truck world would
benefit markedly."
Electronically controlled engines are the only thing selling in the OTR
truck industry. The 10% higher fuel efficiency changes the profit margin. I
think in 10 to 15 years we will have the same opinion about marine diesels,
but in the near term there will be a lot of winning and ...
"But I feel that they have little value on an engine that is run typically
at constant load (ie my boat engines) so would probably opt to not have them
despite reliability. I think real experience in a typical trawler engine
would show no benefit in fuel economy/emissions . . . and what other
improvement does a diesel need?"
Now this is the factually baseless speculation that I am talking about. In
the larger commercial marine diesel engines and OTR trucks, electronic
diesels have demonstrated a >10% improvement in fuel efficiency. According
to the EPA, "When fully implemented, the proposed [marine diesel] standards
would result in a 41 percent reduction in HC [unburned hydrocarbons] +NOx
[nitrogen oxides] and a 22 percent reduction in PM [particulate matter i.e.
black rain stuff] from new engines."
Electronically;
Mike Schooley
Designing "Portager" a 36' trailerable trawler
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