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ADM ran a few of their trucks on ethanol some time back. I think it was during the mid 1990s. The is a writeup somewhere on the internet but I have long ago lost the link.

 

Diesels get better mileage in part because of the higher BTU content in diesel and because they have lower pumping losses due to the lack of a throttle. As I recall ADM took a pretty good hit on mileage using ethanol and at the time it would have been the more expensive fuel since diesel sold for less than gasoline back then. Last summer when diesel prices were around $5.00 a gallon and ethanol was much less than that it may have been cheaper to use ethanol.

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The ADM article interesting, a '92 test . Diesel costs in the chart at $1.05 per gallon....those were the days. One truck logged 325,000 miles on ethanol. The main problem was fuel injector clogging. Glow plugs had to be utilized more frequently. These were Detroit Diesels 9L set up for ethanol electronic controls and compression increased from 18:1 to 23:1.

 

They mentioned while compression increase directly improves engine efficiency....the friction loss cancels out improvement over 16:1. So the ethanol engine was less efficient than diesel with higher compression.

 

The study concluded with E95 diesel conversion easy, no technological problems foreseen, the only barrier would be economics.

 

E95 utilized 5% gasoline to improve injector ignition, they also used "Lubritzol" as ethanol has less lubrication compared to diesel fuel. May this be not required nowadays as ultra low sulfur diesel fuel the same problem. I remember the advice of old diesel owners to mix a cup of vegetable oil with 20 gallon fill up. Vegetable oil very good lubrication.

 

 

 

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The 16:1 optimum compression ratio for engine efficiency changes my thinking about typical diesel engine.

 

The new generation flex ethanol engines utilizing MIT's high turbo charged direct injection seems to be future. Now, talk of sparkless ignition or direct injection ignition upon ethanol engines another bump in efficiency.

 

Higher than normal unleaded compression ratios, turbo charging, and direct injection within the 16:1 ratio may be the best. These second generation flex fuel engines supposidly will replace some diesels. Also, these new engines lighter and smaller than current unleaded engines.  Were talking of 30% improved mpg bringing E85 mileage above regular unleaded.

 

I know the MIT team was injecting 100% ethanol for detonation control, stored in separate fuel tank, but to date have read only reports on fuel injection, variable valve timing, variable turbo, variable compression, etc for utilizing E85. Would just building a nonflex engine only to run on E85 be best?

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The old ADM study was on my mind when I asked if you thought spark or compression ignition was the way to go (thanks for finding it again MUS). I would hate to take too much out of ADM's truck study yet we do know EPA's ethanol engine (spark) did pretty well at 19:1 compression- no word if they actually tried different levels of compression.

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Ya, thanks MUS for the link. Outlaw was the EPA 's (spark) engine a hybrid in VW? I was reading one report of such and was wondering if they were picking up addition efficiencies of hybid? Meaining they didn't separate the engine out?

 

I'm finding most of the technology or R&D moving more into sparkless ignition-

 

Ricado fuel injection technology-

 

“The EBDI engine project is a great example because it turns the gasoline-ethanol equation upside down.  It has the performance of a diesel at the cost of a gasoline engine, and runs on ethanol, gasoline, or a blend of both.”

 

EBDI technology allows, for the first time, for a FlexFuel vehicle to use direct injection optimally for either gas, ethanol or a blend of both.

 

In fact, in the Ricado press release announcing the EBDI technology breakthrough, the company comments that it is currently doing testing on a VW VR6 engine - essentially a naturally aspirated half of the Bentley W12. Ricardo states that its technology works perfectly with high-boost turbocharging to achieve the higher compression required to optimize ethanol combustion.  The company also said that a EBDI VR6 could replace a larger V8 engine - hence our belief that the Bentley Supercar will make more than 630hp.

 

 

GM and University Michigan-

 

An HCCI engine ignites a mixture of fuel and air by compressing it in the cylinder. Unlike a spark ignition petrol or diesel engine, HCCI produces a low-temperature, flameless release of energy throughout the entire combustion chamber. All of the fuel in the chamber is burned simultaneously as instead of a single spark ignition point, the mix spontaneously ignites at several points at once. This produces power similar to today’s conventional petrol engines, but uses less fuel to do it.

 

Leaner fuel air mixes burn well in direct injection combustion. Computer controls, nowadays, makes it easier to control sparkless ignition.

 

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http://www.epa.gov/otaq/presentations/sae-2002-01-2743-v2.pdf

 

The above EPA study was spark ignition 19:5 to 1 compression and since it does not mention vehicle I am sure it was test stand/dyno work.

 

Yes- there are many exciting technologies out there. Let's get a couple of them into affordable daily drivers now before the opportunity is lost.

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I really want more information on the engines mentioned here, even if they would be more complex and expensive than a single fuel engine. Very intriguing...

 

With the disparity between the fuels as to what you can do with each, be it diesel, gasoline or ethanol, an engine dedicated to a specific fuel will be more efficient on that fuel. With the addition of turbocharging and electronic engine controls, we can narrow the gap for a flex fuel engine by adding boost or lowering boost. In essence a variable compression engine, more precisely a variable cylinder pressure engine.

 

In a perfect world we could choose one fuel and build for it, currently with economic, political, and business considerations we need to have flexible fuel vehicles. It is usually quite obvious what type I would rather have.. :) Its still prudent to learn more about what is being done, because even if it doesn't seem relative, it might lead you to another idea that will work.

 

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Interested to read the EPA port injected engine efficiences as good or better than diesel. The engine would be less costly and have good low temperature start up. Something plaguing most 100% ethanol engines.  Ricado Engineering also, utilizes variable EGR dilution for detonation control. Oxygenated fuel characteristics of ethanol can burn efficiently at high EGR dilutions. I'm guessing the chemical exact ratio of oxygen to fuel (stoichiometric ratio) is easy to attain with ethanol. Meaning half the cylinder burn chamber can have inert EGR and the ethanol fuel will burn efficient ratio to air. No lean burn ratios required. It's kind of like decreasing the cubic engine size for low power/pressure. You can't do that with unleaded. 

 

I wonder if the direct injection a better flex fuel engine as having better control in combustion chamber? Or if the direct injection just for ethanol to afford a wide range of fuel mixes? So in effect a EPA port injected engine of unleaded with direct injection of ethanol in combustion chamber? That would be flexible.

 

Were sure going through a technology transformation of IC engines. Lol, the engine may just be a single cylinder that EPA alluded to. A steady state load and rpm engine much more efficient charging batteries. Best pumping efficiencies for most engines around the same, something around 1800 rpm.

 

Ethanol future bright, heck diesel fuel has some growing concerns considering the EPA emissions regs.  Saw a chart whereas 1% of price of unleaded because of refining cost. 17% of the price of diesel from refining cost. Probably because of the ultra low sulfur reg. 

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Ethanol future bright, heck diesel fuel has some growing concerns considering the EPA emissions regs.  Saw a chart whereas 1% of price of unleaded because of refining cost. 17% of the price of diesel from refining cost. Probably because of the ultra low sulfur reg.

 

Refiners have been making their profits on diesel for some time. I think the competition with ethanol has a lot to do with that. I read somewhere recently that the projections are that diesel costs will drop to lower than gasoline in the near future because of new refineries coming online that are capable of producing higher quantities of diesel relative to the amount of gasoline produced.

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