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Old 03-25-2011, 03:10 PM   #21 (permalink)
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...and genuine Unicorn "road apples" are pink, not the usual horse green, due to their rarity (rare, medium, and well-dunned).
They work great in the garden. We get 120# cabbagesfrom unicorn fertilizer.

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Old 03-27-2011, 02:02 PM   #22 (permalink)
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Originally Posted by Air-Hybrid View Post
BTW - anyone know how leaned out an petrol engine can go when mixed with syn-gas (70% CO 30%H2)? ... I'm thinking that Charcoal could used to make Water-gas off the exhaust heat (say, on an artic)?
You'd need a lot extra O2 to burn that mix (both for the H2 and the CO), so you're not leaning it out, but enriching it with fuel.
I was under the impression that adding syngas, in a similar way to adding H2 could extend the lean-burn limit (to beyond the 22:1 ratio) without the burn becoming unstable. That is, no more fuel overall is used compared with normal lean-burn operation, so there is still an excess of O2 at the end of the burn.

There is also evidence that having one of these gaseous fuels (H2, syngas, NG) in the burn will speed up the flame speed - so ensuring that a better portion of the mechanical work can be extracted by the piston, as well as keeping the exhaust valve cooler.
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Old 03-27-2011, 02:49 PM   #23 (permalink)
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But how much extra energy did you use to make the gas ?

The key is here.
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Old 03-27-2011, 03:08 PM   #24 (permalink)
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Air-Hybrid -

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Originally Posted by Air-Hybrid View Post
I was under the impression that adding syngas, in a similar way to adding H2 could extend the lean-burn limit (to beyond the 22:1 ratio) without the burn becoming unstable. That is, no more fuel overall is used compared with normal lean-burn operation, so there is still an excess of O2 at the end of the burn.

There is also evidence that having one of these gaseous fuels (H2, syngas, NG) in the burn will speed up the flame speed - so ensuring that a better portion of the mechanical work can be extracted by the piston, as well as keeping the exhaust valve cooler.
Yes, this has been done in the lab :

Fuzzy Pareto Frontiers in Multidisciplinary System - Architecture Analysis - Page 3
http://web.mit.edu/deweck/www/PDF_ar...-2004-4553.pdf
Quote:
Hydrogen addition affects combustion in an internal combustion engine in several ways. First of all, hydrogen addition can significantly increase flame speed. Flame speed is a primary factor in defining the lean limit - excess air slows down the combustion process to the point of not completing combustion in the time given during the power stroke. Effectively, hydrogen can extend the lean limit by off-setting the reduction in flame speed due to excess air. Secondly, recent work has shown that a hydrogen rich gas can enhance the octane rating of the overall cylinder mixture. This finding has the potential for increasing compression ratio, leading to direct gains in engine efficiency. Figure 1 and 2 illustrate the effect of hydrogen addition and how new system architectures emerge by the shifting of constraints.
Back in 2004 this was being researched at MIT :

Green Car Congress: ArvinMeritor / MIT Plasma Fuel Reformer
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Of particular long-term significance is the official release of the Plasma Fuel Reformer. The Plasma Fuel Reformer uses an electrical plasma (a strong, continuous “spark”) to combust partially a mixture of air and the vechicle’s hydrocarbon fuel -- diesel or gasoline.
...
ArvinMeritor expects the Plasma Fuel Reformer to be in production in 2010. Currently the device is undergoing in-vehicle testing on heavy and light trucks and buses. ArvinMeritor is also exploring using the device in gasoline engines to support ultralean turbocharging, with resulting emissions reduction and fuel efficiency. To that end, it is partnering with Ingenieurgesellschaft Auto und Verkehr (IAV), a German automotive research and development provider.
However, in the years since, Arvin-Meritor sold this R&D off with it's other emissions products and I lost of track of it, so I think it became a dead-end.

This is a search at the Arvin-Meritor site :

Search Arvin-Meritor - Plasma Fuel Reformer

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Old 03-29-2011, 12:54 AM   #25 (permalink)
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maybe you haven't seen this then

MIT professor touts first 'practical' artificial leaf, signs deal with Tata to show up real plants -- Engadget
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Old 03-29-2011, 07:21 AM   #26 (permalink)
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But how much extra energy did you use to make the gas ?

The key is here.
It's a fair point!
The issue with energy is not that we don't per sa have enough of it (commentators talk of the 'energy crisis', etc) - the issue is that the energy is not in the forms we find most useful - ie. 'high-value' forms of energy.

As such - electricity is a high-value energy source, as is liquid fuels like petrol & Diesel. But of course the value is ultimately defined by the application.

The idea behind asking about syn-gas is that it can be made from two low-value energy sources - waste heat & amorphous carbon (from coal or even better charcoal).

I'm not saying this can easily be utilised in a moving vehicle, as just like any other heat recovery device - it adds complexity & weight. But carbon (think of charcoal) is a pretty dense fuel source, but one that could not normally be easily and efficiently used to power an ICE.
But by some simple chemistry, the combination of waste heat (to superheat water) can be combined with carbon to produce syn-gas. Also, if the primary fuel is, for instance Natural Gas, then plenty of H2O can be recovered (condensed out) from the exhaust - reducing the need for carry a large water tank.

And, as 'CFG83' points out - hydrogen rich gases have the potential to improve both the octane rating of a fuel mix and the mean flame speed of the burn - both of which are advantageous for efficiency.
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Old 03-29-2011, 07:28 AM   #27 (permalink)
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Quote:
Originally Posted by Arragonis View Post
But how much extra energy did you use to make the gas ?

The key is here.
It's a fair point!
The issue with energy is not that we don't per sa have enough of it (commentators talk of the 'energy crisis', etc) - the issue is that the energy is not in the forms we find most useful - ie. 'high-value' forms of energy.

As such - electricity is a high-value energy source, as are liquid fuels like petrol & Diesel. But of course the value is ultimately defined by the application.

The idea behind asking about syn-gas is that it can be made from two low-value energy sources - waste heat & amorphous carbon (from coal or even better charcoal).

I'm not saying this can easily be utilised on-board a moving vehicle, as just like any other heat recovery device - it adds complexity & weight. But carbon (think of charcoal) is a pretty dense fuel source, but one that could not normally be easily and efficiently used to power an ICE.
But by some simple chemistry, the combination of waste heat (to superheat water) can be combined with carbon to produce syn-gas. Also, if the primary fuel is, for instance Natural Gas, then plenty of H2O can be recovered (condensed out) from the exhaust - reducing the need for carry a large water tank.

And, as 'CFG83' points out - hydrogen rich gases have the potential to improve both the octane rating of a fuel mix and the mean flame speed of the burn - both of which are advantageous for efficiency.

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