Date: Fri, 19 Apr 2013 20:24:44 -0400
Reply-To: David Beierl <dbeierl@ATTGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Beierl <dbeierl@ATTGLOBAL.NET>
Subject: Re: FRIDAY diesel conversion option
In-Reply-To: <CAFnDXk0pwa-eyR_EwRhn2S0w8Fekb4djf29cGQ4prfYSMDQQQQ@mail.g
mail.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 05:21 PM 4/19/2013, Jim Felder wrote:
>http://www.vincelewis.net/bigengine.html
Some of his numbers are a bit off, partly because this engine can be
built with varying numbers (6-14) of cylinders. Here are numbers for
the largest one, the 14-cylinder:
>Maximum power: 108,920 hp at 102 rpm
>
>Maximum torque: 5,608,312 lb/ft at 102rpm
>
>Fuel consumption at maximum power is 0.278 lbs per hp per hour
>(Brake Specific Fuel Consumption) . Fuel consumption at maximum
>economy is 0.260 lbs/hp/hour. At maximum economy the engine exceeds
>50% thermal efficiency. That is, more than 50% of the energy in the
>fuel in converted to motion.
>
>For comparison, most automotive and small aircraft engines have BSFC
>figures in the 0.40-0.60 lbs/hp/hr range and 25-30% thermal efficiency range.
>
>Even at its most efficient power setting, the big 14 consumes 1,660
>gallons of heavy fuel oil per hour.
(note that the max efficiency setting is about ten rpm down from max
and delivers a bit over half power. Economy aside, the engine could
not be run for long periods at max power without compromising its
lifetime severely. Max continuous *might* be around 80% of full power.)
These engines have computer-operated injection and exhaust valves (I
believe they use ports for intake). I think they can operate down to
0.7 rpm, giving an enormously wider operating range than conventional diesels.
I believe that ships powered by those big Wartzila-Sulzer and Man B&W
engines took over from the bicycle as the most energy-efficient form
of transport on earth short of (bipedal) walking. It's possible they
beat walking as well, can't remember.
If you think a Vanagon is a slug...these folks
<http://www.portrevel.com/>http://www.portrevel.com/ have a
shiphandling school in Grenoble, France, originally owned by Exxon in
the late '60s. It features 1/25 scale model ships that you climb
into and operate. One of their fleet is a model LNG tanker. It
displaces about 23,000 pounds and carries a 2/3 hp motor for
propulsion. This is the same order of magnitude as the
weight-to-power ratio of the ships that carry these truly enormous engines.
Vanagon 2.1l - 2.6 tons max weight, 95 hp, 36 hp per ton.
Real tanker - 180,000 tons max displacement, 52,000 hp, 0.288 hp per
ton. A Vanagon with equivalent power would have 3/4 hp.
Tanker model - 11.52 tons, 0.66 hp, 0.057 hp per ton. Weight and
power are adjusted to the fixed physical scale in order to compress
low-speed maneuvering times by a factor of five compared to the
actual vessel. This trains skippers to keep their wits about them,
so they are relaxed during maneuvers on a real ship.
Real enormous containership - 135,000 tons max displacement, 93,000
hp, 0.689 hp per ton. Vanagon equivalent would have 1.8 hp. These
containerships are fast and have lots (!) of power for their size.
Containership model - 8.64 tons, 1.19 hp, 0.138 hp per ton.
It's the ability to build and support enormous structures in water,
and the total lack of hills, that allows these things. The bigger
you build them, the less material they need to enclose a given volume
of space, and the less power they need proportionally to drive them
through the water at a given speed or punch through the wind. But
acceleration is derisory, and stopping and turning distances are
given in miles. The result is extraordinarily cheap shipping in bulk
or in container lots - and big consequences in an accident.
Yours,
David
| 
