> Cars with MDI engine can store enough air for 125
> miles' driving, or, in city, about 10 hours. It
> carries three tanks which hold a total of about 300
> litres of air. The tanks can be filled within two
> minutes with an air pump. Also in the car is a small
> compresor which can charge the tanks within four hours
> linked to the electricity supply at home.
Now lets see here now; muliply the cubic inch volume capacity of the
engine and then multiply it by the revolutions per minute (RPM)times 10
hours for driving time, hum.
Example 100 cubic inch engine(small) x lets say 1,800 RPM = 180,000
cu in per minute x 60 minutes =108,000,000 cu in per hr
divided via 1728(cubic ft)=6,250 cubic ft x 10 hrs= 62,500 cu ft
What makes one think this is not practicle as one is compressing an
area of about 40ft x 40ft x40ft into an area of lets say a tank of 2ft
rd x 6 ft long = 18 cu ft. (by the looks of the car it couldn't be
larger). So compressing 62,500 cu ft into a tank of only 18 cu ft hum!
`So now lets try the compressing time. Two minutes for 62,500 cu ft
=2,083 cubic feet per minute, I have to tell you this would have to be
one mother of a compressor, not to mention the torque required and the
pressure requirents for a pressure tank.
=>
> However, MDI vehicle is design to run exclusively on
> air compressed. A jet of cold air is delivered at
> hight pressure into de combustion chamber which is
> already charged up with hot compressed air. This
> provides enough force to run the engine.
Not! Highly compressed air is going to be very cold if not frozen
solid, as soon as it enters the compustion chamber it will readily use
the heat from the hot air so no expansion for compression but deflation.
>
> Weighing 34Kg, the 770 cc engine is one-third the
> weight of a normal AX engine and the total weight of
> the car is just about 1650 lb by using carbon-fibre
> for the shell.
Hum, engine is 34 Kg x 2.2 (kilo per lb)=75 lbs with 770 cc.>
==============
> --- LARRY SULLIVAN wrote:
> > Hi Ted et all:
> > If one reads the document carefully it describes
> > the engines as
> > "compressed air assisted" runing on purly compressed
> > air is theory. To
> > me the jest is a fuel effiecent gas engine via
> > compressed air injection.
> > Using the momentum of braking to power the
> > compressor is novel but can
> > be utilized, this is essentually a "air brake".
> > Using compressed air in
> > the compustion chamber would certainly give more
> > power but using cold
> > compressed air into a hot chamber(as in the purely
> > compressed air mode)
> > would only cancell each other out. Running a car on
> > purely compressed
> > air from strorge tanks is simply not practical
> > because one simply could
> > not compress enough volume into the tank.
> > I hate to brake some peoples bubble but I believe
> > I saw the pictures
> > of the car in a promo for a electric fuel cell car.
> > So I shall state again this is simply a stock promo
> > job, "a fool and
> > his money is soon parted".
> >
> > Larry
> >
> =============================================================================
> > >
> > > The Economist. Oct 26, 1996
> > > Car engines - Not all hot air
> > >
> > > THERE is something silly about the four-stroke
> > petrol engine.
> > > Although it is the workhorse of almost all
> > passenger vehicles it
> > > suffers from some glaring inefficiencies. Only one
> > of the four
> > > strokes of the piston provides power to thecar
> > while during
> > > part of another stroke the piston is moving
> > against the pressure
> > > of the ignited fuel. All of this is an extravagant
> > waste of energy.
> > >
> > > Such compromises are necessary because of an
> > oddity in the
> > > engine's design-namely that the initial
> > compression of the
> > > combustible gas its ignition by the spark plug and
> > the
> > > power-producing expansion that follows all occur
> > in one and
> > > the same place at the top of the same cylinder.
> > Over the years
> > > alternative designs have been proposed that ease
> > this
> > > constraint. Guy Negre an engineer in Brignoles in
> > France
> > > whose background is in Formula One engine
> > designthinks he
> > > has hit on a particularly ingenious variant which
> > can run far
> > > more efficiently and cleanly than a four-stroke
> > engine on the
> > > same amount of petrol. As a bonus and without any
> > > modification the engine can also be made to run on
> > nothing
> > > more than compressed air.
> > >
> > > At the heart of Mr Negre's engine is a small
> > combustion
> > > chamber. A piston in a compression cylinder
> > outside this
> > > chamber forces air through a valve into it
> > compressing and thus
> > > heating a mixture of air and petrol in the
> > process. With all
> > > valves to the chamber closed the hot mixture is
> > ignited. The
> > > design of the engine allows the fuel to burn over
> > a period up to
> > > four times longer than in a four-stroke engine.
> > The longer burn
> > > time means that the fuel is consumed far more
> > completely
> > > leading to less in the way of unwanted by-products
> > such as
> > > carbon monoxide and nitrogen oxides.
> <snip>
>
> ===
>
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