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Study finds adding DME to ethanol/diesel emulsion improves performance and lowers fuel consumption and emissions over emulsion or base diesel

Comparing fuel consumption with diesel, 50D/50E and 50D/50E + 7% DME. Credit: ACS, Ashok 2011. Click to enlarge.

In a study published in the ACS journal Energy & Fuels, M. P. Ashok of Annamalai University, Tamil Nadu, India reports that adding dimethyl ether to an ethanol/diesel emulsion results in an increase in brake thermal efficiency and a decrease in specific fuel consumption (SFC), particulate matter, smoke density, and oxides of nitrogen compared to either the emulsion or a base diesel fuel.

Emulsification of diesel with ethanol is one of the possible approaches to improve fuel economy and reduce emissions of pollutants from diesel engines. However, Ashok noted, ethanol addition to diesel results in different physicochemical changes in diesel fuel properties, particularly a reduction in cetane number, viscosity, and heating value. Ashok started the project by first examining the performance of different ethanol/diesel blends: 90D/10E, 80D/20E, 70D/30E, 60D/40E, and 50D/50E, all prepared on the basis of the water-in-oil (W/O)-type emulsion method.

Ashok selected the 50D/50E ratio as the best of the emulsified blends due to its increase in brake thermal efficiency and decrease in specific fuel consumption, smoke density (SD) and PM.

Even though this emulsified fuel gives better brake thermal efficiency and gives less SFC, SD, and PM based on the performance and emissions, respectively, in comparison to diesel no. 2, there is a significant increase in NOx emission over diesel no. 2. This is due to the lower cetane number of ethanol, which causes high temperatures, resulting in a longer ignition delay...This emission of NOx can be controlled by adding a suitable additive, which must have the property of a high cetane number. This leads to a reduction of the temperature, resulting in a smaller ignition delay, thus reducing emission of NOx.

Hence, for this present work, dimethyl ether (DME) has been selected as an additive, because of its high cetane number, noncorrosiveness, and low volatility.

—Ashok 2011

Ashok added DME on a 7% by volume basis with the selected emulsified fuel ratio of 50D/50E and carried out performance, emission, and combustion tests, along with performance and emission tests with diesel no. 2 and emulsified fuel 50D/50E.

Testing was done in a one-cylinder, four-stroke 5.2 kW engine with a compression ratio of 17.5:1. Speed was constant 1500 rpm, injection timing was 23 ° before TDC, and injection pressure was 220 kgf/cm2 (215 bar).

Click to enlarge. Credit: ACS, Ashok 2011.

Among his results were:

  • Brake thermal efficiency increases from 35.6% (emulsified fuel) to 38.1% (DME-added emulsified fuel).

  • There is a difference in SFC of 0.05 kg/kWh between DME-added emulsified fuel and the emulsified fuel.

  • The best decrease in the SD value is obtained for DME-added emulsified fuel compared to the other two fuels. The value for DME-added emulsified fuel and the emulsified fuels are 9.8 and 14.9 HSU, respectively.

  • PM emission is low at lower outputs and equal to the emulsified fuel values at higher outputs for DME-added emulsified fuel.

  • The NOx value is reduced because of the additive DME;it is usually higher for the emulsified fuel using the normal surfactant. NOx was reduced from 3.68 to 2.856 g/kWh for 50D/50E emulsified fuel and DME-added emulsified fuel, respectively.

  • Ignition delay is decreased for DME-added emulsified fuel compared to the other two fuels. At lower output, the difference in value is 4.9° crank angle (CA).

  • The peak pressure and the maximum rate of pressure rise decrease because of the reduction in ignition delay.

  • The heat release rate is higher for the emulsified fuel than the diesel and additive DME-added emulsified fuels. The maximum value obtained by the emulsified fuel is 106.591 kJ m-3 deg-1, and the minimum value attained by the additive DME-added emulsified fuel is 53.81 kJ m-3 deg-1.


  • M. P. Ashok (2011) Effect of Dimethyl Ether in a Selected Ethanol/Diesel Emulsified Fuel Ratio and Comparing the Performance and Emission of the Same to Diesel Fuel. Energy & Fuels Article ASAP doi: 10.1021/ef2007547 |



It is almost impossible that this was not known decades ago. It was probably a well guarded secret to keep fuel consumption as high as possible at the request of Oil Cos.

We have been had for many decades by Oil Cos and vehicle manufacturers and our own governments who collected more taxes.

How stupid-ignorant can we be.


Harvey... drop the conspiracy-theorizing. Seriously.

DME is a gas at room temperature and pressure, so I suspect that DME-supplemented fuel would require a separate DME tank and a system to add and mix DME just before the injector pump. This doesn't sound cheap.


EP.. we rarely had the best fuel. Another recent bad example is the low energy corn derived ethanol that so many are pushing on vehicle owners-users.

Adding an extra tank for large cargo trucks, buses, locomotives and ships would not be a major problem if fuel consumption can be reduced by 25% to 35%, at least until the proper (single tank) mixture is found.

Smaller vehicles should be electrified by 2030 and not use liquid fuels.


I'm with EP - conspiracy theories are non-starters with me. Especially the "who killed the electric car" one.

Thomas Pedersen

This is a pretty weird mix to try out. I'm not surprised, if no-one has done this before! DME is quite new and is only relevant from biofuels. The same goes for D-E emulsion, I suppose.

Is there any chance the emulsion will remain stable in the tank? And that maybe the DME will stay in there as well?

If not, the concept has some difficulty. If yes, what an ingenious way to boost diesel reserves with biofuels and improve performance as well.

Did anyone else notice that the scale goes to 19 kW on two of the graphs - even though it was a 5.2 kW engine..?!


The idea that manufacturers will build what is best for the ends users is a far cry from reality. Maximum profit margin is the main goal not buyers needs. That is why the Big 3 built so many 3 to 4 tons monsters and so few common sense one tonne (or less) vehicles.

One tonne vehicles have the same number of parts to assemble. The assembly cost is almost the same as for 3 to 4 ton monsters but the selling price as to be much lower. Unless you can increase assembly plants productivity or lower and/or reduce the associated labor cost, high profit oriented manufacturers will produce very large vehicles regardless of the real need for such vehicles. Those are the real facts. Japan may be the exception where people stop buying large monsters. They may be smarter buyers than we are or it may be due to much higher gas price.

The same applies to most products we buy. We like to believe that 'we the people' choose our vehicles and other products to match our needs and wallets but that is rarely true. We most often buy what the repeated Ads say what is best for us. That's how so many ended up with large mansions and large vehicles they could not afford to maintain. Banks had a hard time with all the individual bankruptcies in the last few years.

Even the Feds can't balance their budget. President Clinton (the last common sense President) used to spend and collect about 18% of the GDP. He even had surpluses. Today, the Feds collect only 15% and spend almost 25% of the GDP and is getting deeper and deeper in debt. Common sense would reduce spending from 25% to 20% of GDP and increase revenues from 15% to 20% of GDP and end up with a common sense balanced budget. It seems that the majority no longer want that?


I'm with Harvey on the second tank for larger vehicles - including military ones (which tend to be quite large indeed).
A 25-35% efficiency gain is really something, (and you could still hybridise it (hydraulic or electric)) for city buses etc.


I and some of my friends have been running diesel engines for several years doped with DME. When I suggested using an air-cooled, two cyclinder opposed diesel to power a gen-set, it goes without saying that would involve DME.

China is making very large amounts of it. I assume they are using it for something involving transportation.


My post seems to have disappeared, which is weird. I suggested that DMF which is liquid at room temperatures might have similar effects to DME as a fuel blend.


Harvey you jump from one childish paranoia to another.

Our next step is to cast off the idea that manufacturers (like automakers) do not (did not) build the products that people wanted at a price people would pay.

You must stop blaming brainwashing for the fact that people did not buy what you wanted them to - they bought what THEY wanted (like big cars, even with the availability of low cost imported small cars).

I cannot believe any adult would have the patience to repeat this BS enough times that they would actually start to believe it.

Sincerely yours,
with constructive criticism,

Roger Pham

Don't believe the result of this experiment yet, or do not extrapolate the result of this study into automotive or heavy-duty diesel engines.

The posted SFC for diesel fuel at .36 kg/kWh would calculate to only 22% thermal efficiency. That is simply too low for even a small diesel engine running on diesel #2 fuel, which should get about 34% thermal efficiency. The thermal efficiency of 50D:50E is more believable at 35.6%. Perhaps this 5-kW single-cylinder diesel engine is too small to be extrapolated to larger turbo diesel engines. There was no mention in the article whether this is a DI or IDI diesel, nor whether it was turbocharged or not.


Oil Companies will stop at nothing to derail hydrogen, thorium reactors and ethanol made from hemp.. they have 100 years of buried patents to disclose at the appropriate time to dry up funding for new age energy techs. Do not be fooled.


TT....the majority will have to wake up sooner or latter because they will be the victims of the current Monopoly game. Printing more and more devalued US $$ + borrowing more and more from China and the Middle East Kingdoms + selling off existing assets + importing more and more crude oil and consumables may not be possible or enough after 2020.

We may not like it, but we will have to learn to consume less, drive much smaller vehicles and live in smaller homes, even if we do not like them. We may not be able to afford more.

Sorry, but that is what we may be facing the majority before the end of the current decade. Increasing the National debt from 14.3T to 17.3T or even 20.3T is a short term fix. It is NOT addressing the long term structural problem.

Roger Pham

For the short term, we (USA) will have to suffer from the mistakes of GWB et al.

In the long term, the USA has tremendous human resources and natural resources that will support a high standard of living just like in the past.

We will need to wean off certain types of dependencies and sober up:
1. Avoid depending too much on cheap immigrant labor, legal or illegal, nor too much on foreign talents, but try to develop those at home. How much did we spend on education, again?
2. Avoid depending too much on cheap foreign labor (cheap imports) that will take away local jobs, creativity, hopes, know-how, pride, etc...
3. Avoid depending on expensive foreign oil and gas importation that will periodially collapse our economy due to energy price hike and shortage. Switch to renewable energy produced locally that will employ local labor, grow the economy, provides local jobs, increase the pay rolls thereby increase the tax base to help balance the budget,
4. The Gov. should avoid depending on borrowed money to fund entitlements, porks, illegal wars, etc...
In fact, try to live within our means and avoid borrowing money at all.

Other than the above, I see a lot of room for optimism past the immediate crisis, as long as all citizens will be taught to think like a true citizen of the USA, and put the interests of the USA above all those selfish and destructive personal interests. Together, we can do it. United, We Stand!


Yes Harvey, the majority IS waking up to the current Monopoly game of printing more and more devalued US $$ + borrowing more and more from China and the Middle East Kingdoms + selling off existing assets + importing more and more crude oil and consumables.

And yes, we will likely have to learn to consume less, drive much smaller vehicles and live in smaller homes. We may not be able to afford more.

Increasing the National debt from 14.3T to 17.3T or even 20.3T is NOT even a short term fix, it is a patch. And no, it is NOT addressing the long term structural problem.

So what does this have to do with the fantasy that manufacturers must build what you (or anyone else) think is best for the ends users.

Or the fantasy that that maximum profit margin should NOT be their main goal.

Or that maximum profit margin is inconsistent with meeting buyers needs.

Or the fantasy that people did not want the 3 to 4 tons monsters the Big 3 built (and sold to the people).


"For the short term, we (USA) will have to suffer from the mistakes of GWB et al."


Guess what?
He is NO LONGER the president.

Is he the only one that has done anything?

Well, the only president that has.

Oh wait, didn't Obama help shoot Bin Ladin? Ummm NO.

Didn't he lead us to a balanced budget? Naa
Did he get us out of Guantanimo? Naa.
Out of unemployment? Naa
Out of Afganistan, Iraq and Lybia? Naa Naa Naa

Many oppose Obama's reelection simply because the world might see us still blaming GWB for our problems.

Roger Pham

Well, TT, let me take back my former accusation of GWB, and give him some praises: He was one of the most successful US President ever, for bringing back untold $$$ for his supporters. Oil Cos made biggest profits ever under his helm, and so did Defense Cos, and so did the top income bracket people with the biggest tax break. What about the American people, what did he (GWB) bring back to them? Uh...They didn't vote for him in the first place, they voted for Al Gore, so scr*w 'em!

Let me put the blame for the bankrupting of America to OBL, who was the man with the highest net worth ever in history. Bill Gates didn't even come close! His life was worth >3 Trillions of USD's of US gov expenditure spent on finding him until they can get to him, as well as all the US servicemen's lives lost in the search for OBL, that easily triple the US's lives lost during 911, and all the US servicemen's who've been made crippled in the search for OBL, numbered easily ten folds the number of US lives lost at 911. Adding trillions USD more of economic cost for the USA from the oil price escalation in 2008 and the bailouts...to OBL's score card! It all started since 911 that helped got GWB re-elected! A truly dangerous and fearsom enemy, indeed!
So, it was OBL who deserved all the blame for our misery at the moment, and we all should thank GWB for having set in motion all that was necessary to bring OBL to martyrdom. Worse, OBL may be looking down from Islamic heaven right now at all the Infidels who are scurrying to avert the next socio-economic-existential crisis!


What does this have to do with DME again?

The US consumer "prefers" big vehicles because (a) they have been marketed very heavily, and (b) the US government has pursued a "cheap fuel" policy in the interests of the oil industry (and against the interests of the American public). Oil price spikes have overcome the big-truck marketing push and pushed sales to more economical vehicles, but the memory of Americans is very short.

Policy could easily reverse much of the "preference" by making economy more desirable. Higher fuel taxes and various disabilities for gas guzzlers (e.g. lower speed limits, higher registration fees, lane restrictions) would shift buyer preference immediately.

Account Deleted

The DME is a gas at room temperature and pressure, so I suspect that DME-supplemented fuel would require a separate DME tank and a system to add and mix DME just before the injector pump.get your ex back !venapro reviews

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