h a l f b a k e r yMake mine a double.
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A possibly cobber tube filled with regular water is drawn
around the entire (or less) length of the ICE exhaust
system.
The water is supplied to the coil by just gravity, from a
tank of say 20-30 liters (10 gallons) at the rear part of the
car/vehicle.
The water is heated, at steady-state
high way speeds,
from the exhasut heat, and propels naturally towards to
front of the vehicle, to the engine compartment, where it
takes the flash heat from the headers, also.
The water, now low pressure steam, at 200 - 400 degrees
celcius, is sprayed into the intake manifold, where the
energy/enthalpy/enthropy, is joined up with the regular
intake air.
This decreases the temperature difference losses in the
regular four-stroke ICE cycle, in that both the intake air
flow is pre-heated, and possibly, safely, the gasoline
intake flow is heated also.
This allows the burning at higher inlet/initial
temperatures, saving heat lost in the moment of
combustion, exchanged otherwise at highly inefficient
turbulent conditions.
The potential saving is the about 30 % energy lost to
exhaust heat, turned into temperauture increases in the
intake flows.
How engines work
http://estore.ricar...roduct.asp?P_ID=149
The definitive work on the subject. [Twizz, Jun 02 2011]
People tried it. It didn't do any good.
http://www.metrompg.../posts/wai-test.htm
These people are pretty hardened. Modern EFI is already compensating for IAT. [WcW, Jun 02 2011]
Cyclone engine
http://www.cyclonepower.com/
Serious heat recovery [Twizz, Jun 03 2011]
State-of-Product's in production, at Ford. 2011.
http://www.gizmag.c...der-ecoboost/18814/
1000 cc 4-stroke turbo-engine, 3-cylinder's, simplyfied. [sirau, Jun 06 2011]
Ambient pressure, and even temperature process,, hydrogen.
http://www.gizmag.c...ogen-ethanol/18755/
- a slight spray additionally,, and wow, there she goes,,..s. [sirau, Jun 06 2011]
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//temperature difference losses// ?? Engines are powered by the difference between intake temperature and combustion temperature. Cold air good, hot air bad. |
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If you injected 200 - 400ºC pressurised _liquid_ water into the cylinders then you might do some good (especially using a 6-stroke cycle), but allowing it to expand to steam and mix with the intake air outside of the cylinder is worse than useless. |
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temperature : It would even out pressures, so the
throtle could be wide open, lessening the pumping
losses (not pulling the vacuum, at cruising speeds). |
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It's not the temperature profiles, that generates
power (temperature can only be lost, never
recovered), it's the pressure on the mechanicals,
that is productive, and generates forward motion. |
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NASCAR could use this-- as an overly-complicated
horsepower-reduction alternative to the intake restrictor
plate. |
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sirau this is embarrassing. |
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We precool air to get more power because it allows more air into the cylinder, but what about when the application is for *less* power ? |
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Why not preheat the air for when you're just tooling around town ? or using a constant 20HP on the highway. Then you get *less* air into the cylinder to match up with the less fuel... on purpose. |
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(Not sure about the steam bit though) |
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and less efficiency. why? |
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//why?// Because you can play with the fuel:air ratio. Why would you say it's less efficient ? ; for starters you're not pumping around that much more dead weight. |
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we already have a way to change the a/f ratio. |
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Generally speaking, all other things being equal, the ratio between the low and the high side, up to the ratios discovered by Carnot, is a measure of efficiency; higher is better. |
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umm... okay... then the homework for the day is to find out if preheating the air results in a higher or lower temperature of combustion, thus a greater or smaller difference to ambient. |
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Bear in mind I'm just focusing on the times when you don't want a full 200HP out of your engine so the cylinders at that time are too big for the application... so you don't fill them up as much, by using heated air instead of ambient or cooled. |
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This could be used as an ejector/injector to introduce additional air at high load, or make up for some throttling losses at part load. However, the gain would have to be set against the losses involved with heating the inlet air. |
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So long as you managed to use a small volume of steam at very high pressure compared to the inlet air flow this might give a benefit. Bear in mind though that there isn't that much heat in the exhaust when cruising under part load. |
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This will also increase the thermal capacity within the cobustion chamber, leading to improved NOx emissions but lower exhaust temperatures (which you're relying on for your heat source). |
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Overall: Probably a very complicated and difficult to develop system with minimal gains (unless it turns out to be a terrific new method of boosting!). |
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just to point out : it's a way to reduce heat losses,
that's it !!, and thereby increase efficiency, at
regular high-way cruising, where not much power
is needed (in relation to the maximum power
available, used for accelleration, hills, towing, and
other). |
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The heat recovered from the exhaust, is utilized
to : |
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1. Pre-heat intake air flow, |
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(at stochionmetric, the intake air mass flow is 14-
16 times that of the fuel flow, ie. burn one kilo of
fuel, and you'll need approx. 15 kilo's of air, eg.
one to four kilo's of intake charge, per kilometer) |
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2. Heat the fuel safely, as to a level below self-
igniting, to gain the energy/work/power flow of
the vaporisation heat/energy, of the liquid-to-
gaseous phase of the fuel. |
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This can easily be looked up, as the difference
between 'lower heat value' and 'higher heat value',
in a Kilo Joule per Kilogramme terms unit figure. |
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In a formal energy cycle diagram, like the carnot
cycle referenced, this exhaust energy recycling
will appear as a incirculation of an energy/power
area below the Otto-cycle incirculation. |
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Something that could be grasped as a : |
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'thermal laminar flow liquid stationary zero-
pressure 'turbo' charger efficiency cycle' - |
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equipment addition to the very advanced and
refined Internal Combustion Engine technology,
already on the market. |
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('turbo' referring to the 'rotation' of the energy
(flow), or really : heat 'cycling', or 'recuperating'). |
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When I studied Automotive Engineering, (in
Leeds, The North, England), there was a real world
investigation result of consumers's car's energy
efficiency : |
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Only 12 % efficiency was the average result, for a
gasoline fueled ICE, lumpering about in the real
world. |
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Another rule of thumb, is that at least 30 % of the
latent heat energy of the fuel in ICE's, goes lost
through the exhaust gasses. |
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Taken from these figures alone : |
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If 12 % is utilized, and 30 % additionally is
recuperated, then the efficiency goes to : |
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four times up, !!. (That's the potential, roughly
calculated). |
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omfg even the logic of the math is ridiculous. how do you account for the fact that this principal of thermodynamics has gone unnoticed for hundreds of years? Why not simply pipe 100% of the exhaust heat back into the intake? |
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The '30%' is the entire (your '100%') exhaust heat. |
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Therefore, not all (less than 100%) of the 30 % heat
otherwise lost to the exhaust flow can be
recovered, nothings that perfect,. |
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There will be the flow of kinetic energy still, ie.
mass flow times velocity (not velocity squared,.),
since the gasses shall and must be
evacuated/gotten rid off. |
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There will be residual temperature between the
exhaust gas, after having transfered most of it's
temperature/heat to the transfer water/steam
tubing, towards the ambient temperature (at
which the water at the inlet of the tube is
thought to be at). This heat is still lost. |
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The calculation is of course a provocation, but it's
a perspective of the proportions involved. |
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the in his time respected and inside-industry well
known Mr. Smokey Younick, Texas I think, worked
on recovering exhaust heat, with a sponsored
Pontiac Fiero 4-cylinder 2.5 liter car and engine. |
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His take on it, was to heat the intake air in two-
three stages : to 100-120 degrees C in an outside
cooling water plenum under the standard
carburetor, and leading the intake flow around the
outside of the standard cast exhaust manifold,
taking the incoming air-fuel charge to 200-220
degrees C, with a presumably standard turbo-
charger compressor/turbine in between, with the
dual function of mechanically evening
out/equalizing the air-fuel charge, vaporizing all
micro-scopic droplets fully, and functioning as a
'active back-flow valve', keeping the charge under
pressure, under the otherwise expanding
conditions of the heating (pre-heating, before
combustion). |
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Mr. Younicks results were good : 1 HP per cubic
inch, = 100 HP per liter, ie. 250 HP, and equivalent,
reliable, flat, torque curve. |
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It was a four page featured article in 'Hot Rod
Magazine', way back in 1987 (the issue with a
Bright Orange rebuilt Chevrolet 1957 'Bel-Air' on
the cover.). |
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I have sent a copy of the Hot Rod article to the
engine efficiency responsible engineer, at Alfa
Romeo's research center, in Arese, near
Rho/Milan, in the region of Lombardia, Italy. I
haven't seen any direct application of such
temperature, or equalization of droplets, in their
market supply. They have their 'cylinder direct fuel
injection' system, also used at Ferrari, I gather
inspired by develoments in materials for injector
tips, in the diesel technology. But, Alfa and Ferrari
consumers are not that hung up on effiency, they
like outright power, :-). |
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//keeping the charge under pressure, under the otherwise expanding conditions of the heating// That makes a big difference; the expanding heated inlet air is then able to do work against the pistons. |
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In your idea, all the work is done against the atmosphere, and therefore wasted. In addition, less work is able to be done inside the cylinder, as the pre-heated air is not able to expand as much (the amount of expansion is proportional to the ratio of absolute temperature, not the difference in temperatures). That's why I think it will be worse than useless. |
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as noted before : it's the mechanical power that is
needed/produced, the termal parts of the cycles
involved are there to facilitate the pressures,
giving the mechanical power. |
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If you would care to see it in this perspective : |
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Then the entire temperature increase, from
ambient to combustion chamber internal/medium
temperature, is all a loss of energy (!!!!!!). A
complete loss (seen by observing that the
temperature/heat is eventually discharded/lost,
out the exhaust pipe). |
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Therefore, if the inlet air-stream
temperature is raised, by re-cycling exhaust heat,
the waste is less. |
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Inlet before modification : 20 degrees C (293
Kelvin), ambient temperature |
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Combustion chamber median temperature : ?? =
1000 degrees C (1.273 Kelvin) |
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Exhaust final outlet pipe end temperature : 100
degrees C (373 Kelvin) |
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Inlet after modification : 200 degrees C (573
Kelvin) |
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Combustion chamber median : 1.200 degrees C
(1.573 Kelvin) |
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Exhaust outlet pipe temp. : 60 degrees C (333
Kelvin) |
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The Otto four stroke power cycle diagram is
unchanged in vertical and horizontal aspects, only
it is moved, say 200 degrees C, up, the incircled
area, and hence the energy and power produced,
is the same. |
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But an additional power cycle incirculation is to be
included : the energy saving 20 degrees to 200
degrees inlet air flow raised temperature ! + Plus
the phase transition of the heating of the fuel,
from liquid to gaseous form. |
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I would like to run some more specific numbers,
but it's the specific heat of atmospheric air, at a
process from 20 to 200 degrees Celsius, x times a
mass proportion of 15 (stochiometric), plus the
specific heat of gasoline, also from 20 to 200
degrees Celsius, x times a mass proportion of 1
(one), + plus the mass specific difference between
'lower heat value' and 'higher heat value' of
gasoline, x times 1 (one) mass proportion, also,,,,,,
these three added together, and
then the total, divided by x 1 (one) mass
proportion x times the average heat value,
achieved in combustion by the before-
modification configuration (manufacturers and oil
companies uses the lower heat value, normally, as
a reference). |
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At this time, I cannot even guess at the results of
such a detailed calculation. This would evaluate
the potential and scope of the suggested addition
to cars, fairly, and accurately. |
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Royalty/license fee claim : 10 % of material costs, 1,0
% of projected first 10.000 kilometers fuel costs
saved, by entire applied sold fleet of vehicles,. :-
))))). |
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The exit remark from the Hot Rod article, as to
what was next to be expected, from/by Mr.
Smokey Younick, was that he would be looking
into Ceramic Materials, for the involved
mechanical parts. This to increase operating
temperatures, safely, as the ceramics will stand up
to 1.400 - 1.800 degrees Celsius, without
deteriorating, physically/chemically. |
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The article stated that his engines were operating
at 80 % effiency, and that with ceramic
components, closer to 100 % (!!), should be
expected. |
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Sirau - seriously, read Ricardo or any other work on heat engines. |
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Exhaust gas heat is not entirely wasted in modern engines. Cooling the exhaust increases the gas density and reduces it's velocity, also reducing extraction effects. |
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While it is true that there is some energy which could be recovered, in a motor car it is not practical because the size and mass of the recovery equipment outweighs the benefits. |
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For some serious efforts in heat recovery, take a look at the Cyclone engine (not and IC engine). This guy has achieved over 32% effecicency (that's 32% of fuel energy converted to mechanical output at the shaft) which exceeds the best modern diesels. |
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I will present the detailed numbers some day. |
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A prototype even, if the calc is favourable. |
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15 meters of coiled up thin-walled cobber tubing will
be less than 3 kilo's, and an additional cost to
consumers of say 100-200 USD/EUR, completely and
fully engineered, and installed on the assembly line
(an additional feature/work off-line, done by the
exhaust system manufacturer). |
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I had a look at the Cyclone page : 3200 psi's pressure
is equal to 230 atm,,. Could possibly be increased, to
increase power-work-flow to weight/installation
space ratio. |
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And , the Cyclone engine, even if ever so
complicated (possibly reduced to the complexity of a
refridgeator compressor,..), could be applied in
parallel to a regular ICE, feeding off the ICE exhaust
heat, instead of burning fuel inside itself. |
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A two stroke could yield the same enrgy/force
profile, at 30 % less material take-off, and lugging-
about installed weight. With direct fuel injection,
and newest materials, higher rev's and wider
power band possibly also. Two stroke with Turbo,
and ceramics from plasma spraying onto cheeper
metal parts. For long distances, an steam energy
transfer exhaust-to-inlet air energy exchange,
would decrease lower- to -higher- specific burn-
heat value, and elevate peak process temperature
of the individual 'inlet charge' batches, also
incresing efficiency, inherently. |
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A 12-13 kilo's added weight, and it's a bi-fuel (tri-
including water/steam :-) ), solar ray surface on roof,
reactor canister in the lowest part's. |
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