Facts or myths?

[Buckman]

I stress this is NOT my article as it is copied from a car forum, but I thought it could be of interest to some however I am not sure whether it is fact or fiction, but maybe someone with more savvy than myself when it comes to fuel can advise? Where possible I always fill up to the brim when refueling unless motorway then it is just enough to get to my destination with a bit to spare, but never had to do the latter.


I read this news article today which I believe is an example of 'gaslighting' UK motorists. It makes people believe they are responsible for their car fuel pump failures when really it's the ethanol content in the fuel.

To debunk this article I present the facts before you so that you can validate them yourself and correct me if I am wrong.

The purpose of a fuel filter is to protect the fuel pump and fuel injectors from solid contaminants above a certain particle size. The fuel filter is always located upstream of the pump to prevent particles from reaching the pump. They are often a replaceable component during vehicle servicing. The fuel filter does not remove water from the fuel although some diesel filtration systems can perform a level of water separation.

There is no difference to the amount of particle disturbance or particle introduction into a fuel tank by adding fuel in smaller quantities. The act of pouring in fuel disturbs whatever is in the tank in any case. If the solid body contaminants are already in the retail fuel, filling the tank introduces more contaminants.

Driving a petrol or diesel vehicle will cause the fuel to slosh about in the tank. By design, the tank will have an air space above the fuel. Tank baffles reduce fuel sloshing but the fill capacity will not affect the performance of the baffles. Every pot hole, corner, acceleration and braking will cause the fuel to slosh irrespective of fuel level.

Ethanol in fuel absorbs water vapour from the atmosphere and it quickly contaminates the fuel. Although modern cars are sold as being able to run on ethanol fuel, they are not able to run properly on a blend of ethanol+water+fuel as the water and ethanol are corrosive.

Filling your fuel tank with only a few more litres than you need for your journey saves fuel as your vehicle is lighter (less fuel mass). Using F=ma (Force = mass x acceleration), a greater mass for the same acceleration requires more force. In a car, more force means more energy input required.

The real reason behind the misinformation article...

The ethanol blended fuel we are forced to use in the UK absorbs moisture from the air faster in a partially filled tank than in a full tank, particularly if the car is not used daily. The absorbed water content in the contaminated fuel causes vehicle fuel pumps and fuel injectors to fail. The news paper article makes no mention of this fact as it is clearly written to make the ignorant believe that they damaged their vehicle by trying to drive fuel efficiently, when really the government or political forces that determine policies are to blame by adding ethanol to road fuels. Having a full tank reduces the air space above the tank fuel level which in turn reduces the quantity of water vapour in that air. However, tanks are vented to atmosphere by a small bore pipe. If left for a long period of time, a full fuel tank will eventually absorb the same percentage of water from the air.

Ethanol in UK petrol and diesel increases CO2 output globally by displacing food production from the UK to other countries that export food to the UK by sea or air. The ethanol in fuel also reduces engine performance by at least 3% requiring more fuel to cover the same distance travelled. Ethanol in fuel has been a known carcinogen to the government of California since at least 1997 . Somehow, increasing cancer cases globally from the high aldehyde emission of ethanol blended fuel is not considered a serious enough problem to make it illegal to use in fuel blends.

 

[otherclive]

Ethanol has been used in U.K. and European petrol for many years now, and I would have expected to have read about a rash of fuel pump problems. In the US E85 came in even earlier and again no bad press. In Brazil there have been high percentage bio mixes for even longer. So I’m quite happy to live with the current specification of fuel.

Admittedly water in fuel isn’t great news but how many reports of fuel pump failures do we read? In Canada during winter 1985 I periodically dosed the Jeep petrol with a water miscible agent that could then burn in the engine. But that fuel then had no ethanol content to speak of.

The biggest risk to a fuel pump must be particulate contamination or infrequent use of the vehicle.

“ Use it or lose it”

 

[RogerL]

When ethanol was being considered as a fuel additive, the main concern was deterioration of the fuel pipes but subsequent changes in specification have eliminated that issue prior to the introduction of biofuel blends.

For most of automotive history, steel fuel tanks were used - air drawn into the tanks as the fuel was used will condense overnight on the sides of the steel tank and run down to the bottom of the tank where it's drawn into the pipework and on to the engine. Modern cars mostly have plastic fuel tanks with greatly reduced condensation.

Like OC, I have no issues using B10 petrol (10% ethanol) in our Citroen C1, despite the fact that its short journeys means it only gets refuelled 3-4 times/year.

 

[JTQ]

For most of automotive history, steel fuel tanks were used - air drawn into the tanks as the fuel was used will condense overnight on the sides of the steel tank and run down to the bottom of the tank where it's drawn into the pipework and on to the engine. Modern cars mostly have plastic fuel tanks with greatly reduced condensation.

More an issue with diesel tanks than petrol as petrol in our ambient is volatile, so as the temperature fluctuate the tank's void remains filled with petrol vapour.
Whereas diesel is far less volatile in our ambient and the tank void does "breathe" in as temperatures drop, introducing the potential for atmospheric moisture to condense, with all the corrosion and biological implications that can bring. As said greatly eased by the adoption of plastic as opposed to metal tanks.

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I am not up to speed on the design of modern automotive fuel filtering technology, but over 25 years ago the technology to coalesce water in the "filter" was well adopted in capital project's diesel-powered fuel systems.
By coalescing the water carried as micro droplets within the fuel, was as the name implies "coalesced" into larger droplets able under gravity to wick down the fibres and collect in the filter's sump. I would be staggered to hear such simply applied technology has not yet made it to automotive fuel filters. I think I even remember my last century diesel car had a water drain plug on its fuel filter?

 

[Jcloughie]

I trust the car/engine manufacturers, and fuel manufacturers produce the best product they can given cost restraints and staying within legal parameters.

Therefore, I just fill up as required, and get it regularly serviced.

I forget how often the fuel filter should be changed in my car, but I do recall it is surprisingly large and expensive.

There is much information, myths and old wives tales regarding what is best, including additives. My recent cars handbooks have strongly recommended against using any additives. So I don’t.

John

 

[otherclive]

More an issue with diesel tanks than petrol as petrol in our ambient is volatile, so as the temperature fluctuate the tank's void remains filled with petrol vapour.
Whereas diesel is far less volatile in our ambient and the tank void does "breathe" in as temperatures drop, introducing the potential for atmospheric moisture to condense, with all the corrosion and biological implications that can bring. As said greatly eased by the adoption of plastic as opposed to metal tanks.

---------------------------------------

I am not up to speed on the design of modern automotive fuel filtering technology, but over 25 years ago the technology to coalesce water in the "filter" was well adopted in capital project's diesel-powered fuel systems.
By coalescing the water carried as micro droplets within the fuel, was as the name implies "coalesced" into larger droplets able under gravity to wick down the fibres and collect in the filter's sump. I would be staggered to hear such simply applied technology has not yet made it to automotive fuel filters. I think I even remember my last century diesel car had a water drain plug on its fuel filter?

My 1995 Pajero had a drain on the fuel filter. Rarely did I get anything significant out.

 

[Raywood]

When ethanol was being considered as a fuel additive, the main concern was deterioration of the fuel pipes but subsequent changes in specification have eliminated that issue prior to the introduction of biofuel blends.

For most of automotive history, steel fuel tanks were used - air drawn into the tanks as the fuel was used will condense overnight on the sides of the steel tank and run down to the bottom of the tank where it's drawn into the pipework and on to the engine. Modern cars mostly have plastic fuel tanks with greatly reduced condensation.

Like OC, I have no issues using B10 petrol (10% ethanol) in our Citroen C1, despite the fact that its short journeys means it only gets refuelled 3-4 times/year.

I use it but my MPG is down probably about 5% or more so the idea that harmful emissions are reduced by 10% does not hold up as this seems to be common.

 

[ProfJohnL]

I use it but my MPG is down probably about 5% or more so the idea that harmful emissions are reduced by 10% does not hold up as this seems to be common.

It's not a simple mathematical comparison related to MPG. It's the chemical composition and how its burned that affects what emissions are produced.

 

[otherclive]

It's not a simple mathematical comparison related to MPG. It's the chemical composition and how its burned that affects what emissions are produced.

The emissions of relevance are carbon dioxide across the complete supply chain, not just the carbon dioxide produced by the cars engine.

 

[ProfJohnL]

The emissions of relevance are carbon dioxide across the complete supply chain, not just the carbon dioxide produced by the cars engine.

CO2 is definitely a concern, but the issue of harmful emissions covers a much wider spread of compounds, and which are present and in what proportion is down to what the fuel is, and quantity used and the way the it's burned, all of which contribute to the emissions produced.

 

[otherclive]

CO2 is definitely a concern, but the issue of harmful emissions covers a much wider spread of compounds, and which are present and in what proportion is down to what the fuel is, and quantity used and the way the it's burned, all of which contribute to the emissions produced.

I agree that in the round an engine produces more pollutants than just CO2 but getting back to the OP the ethanol being added to petrol is intended to reduce carbon dioxide emissions. The fact that engines running on E10 are reported to have reduced mpg which on the face of it would question benefits if increasing ethanol content from E5 to E10. But it’s the complete supply chain that has to be addressed including the source and transport of the ethanol as well as the use in petrol. Some studies report that the complete life cycle produces more CO2, but others show the reverse. .

 

[JTQ]

CO2 is definitely a concern, but the issue of harmful emissions covers a much wider spread of compounds, and which are present and in what proportion is down to what the fuel is, and quantity used and the way the it's burned, all of which contribute to the emissions produced.

Not least of which is any additive they or we put into the fuel to "improve" the combustion characteristics, as sadly was the case with the now banned here, lead compounds.
Everything that goes into the engine, either it or its combustion products come out, either into the atmosphere or cluttering up the DPF or other piece of the exhaust tract.

 

[ProfJohnL]

I agree that in the round an engine produces more pollutants than just CO2 but getting back to the OP the ethanol being added to petrol is intended to reduce carbon dioxide emissions. The fact that engines running on E10 are reported to have reduced mpg which on the face of it would question benefits if increasing ethanol content from E5 to E10. But it’s the complete supply chain that has to be addressed including the source and transport of the ethanol as well as the use in petrol. Some studies report that the complete life cycle produces more CO2, but others show the reverse. .

If you try to include the whole supply chain emissions the picture becomes really fuzzy, as the contributions by each stage could be different depending on where the raw crude comes from, and specific methods employed by each company to refine, store and transport the fuel. So for Ray's purpose, it's only practical to look at the emissions produced by the car.

 

[ProfJohnL]

I use it but my MPG is down probably about 5% or more so the idea that harmful emissions are reduced by 10% does not hold up as this seems to be common.

Further to my earlier reply,

A loss of 5% or more MPG in terms of E10 vs E5 fuel seems excessive. According to the Times Money Mentour web site the typical drop in MPG is only 2 to 3%, but they go on to point out that such differences on MPG are easily masked by by driving style and conditions.

The Government accepts there is a 1 to 2% reduction in MPG

I'd venture to suggest your "5% or more" is not purely down to the change in the E value.

 

[Buckman]

Ethanol in fuel has been a known carcinogen to the government of California since at least 1997 . Somehow, increasing cancer cases globally from the high aldehyde emission of ethanol blended fuel is not considered a serious enough problem to make it illegal to use in fuel blends.

As we only use the petrol Corolla for short distances, we fill up about once every 4 - 6 weeks or when the tank is down to quarter full. Although we are in a rural area generally the furtherest it travels is a 28 mile round trip into the town.

However I am a bit surprised that no one is mentioning the possible health issues connected to using ethanol?

 

[Raywood]

Further to my earlier reply,

A loss of 5% or more MPG in terms of E10 vs E5 fuel seems excessive. According to the Times Money Mentour web site the typical drop in MPG is only 2 to 3%, but they go on to point out that such differences on MPG are easily masked by by driving style and conditions.

The Government accepts there is a 1 to 2% reduction in MPG

I'd venture to suggest your "5% or more" is not purely down to the change in the E value.

Since I noticed it I have tried more than ever to keep the consumption rate down but I cannot get it down to anything seriously below this and I always drive with economy in mind. I am not sure if the difference may vary between makes but I have heard far larger figures mentioned and simply do not believe the government figures. Is it possible that the Times figure is a result of people seeing the lower mileage figures in their own usage and making a decision to drive more economically and skewing the figures.

 

[Hutch]

Does anyone actually use the economy mode in their car, that is if you have that feature.

 

[Beachball]

Does anyone actually use the economy mode in their car, that is if you have that feature.

I use it all the time in my car and i have that item

 

[ProfJohnL]

Does anyone actually use the economy mode in their car, that is if you have that feature.

Most of the time.

 

[ProfJohnL]

Since I noticed it I have tried more than ever to keep the consumption rate down but I cannot get it down to anything seriously below this and I always drive with economy in mind. I am not sure if the difference may vary between makes but I have heard far larger figures mentioned and simply do not believe the government figures. Is it possible that the Times figure is a result of people seeing the lower mileage figures in their own usage and making a decision to drive more economically and skewing the figures.

I should have made it clearer, I don't believe the Government figure either. But the Times figures seem more reasonable and logical., But its very difficult to accurately assess such differences in real life as the road and weather conditions can create significant additional variable factors which will mask the variations attributable to just the fuel type.

 

[otherclive]

Does anyone actually use the economy mode in their car, that is if you have that feature.

I do for most of my trips. There’s a Sport mode that does crispen up the engine response but just like with my previous Forester XT rarely used it when not towing.

 

[RogerL]

Since I noticed it I have tried more than ever to keep the consumption rate down but I cannot get it down to anything seriously below this and I always drive with economy in mind. I am not sure if the difference may vary between makes but I have heard far larger figures mentioned and simply do not believe the government figures. Is it possible that the Times figure is a result of people seeing the lower mileage figures in their own usage and making a decision to drive more economically and skewing the figures.

It's not an easy thing to analyse since the 5% in E5 and 10% in E10 are maximums, not actuals - so we don't know what the actual difference is between the two fuels.

 

[RogerL]

Does anyone actually use the economy mode in their car, that is if you have that feature.

Most cars with an "Eco" mode just relabel "Drive" or "Normal" to make the owners feel better!

When I want to drive economically - I take the little Citroen C1 !!!

 

[Buckman]

Does anyone actually use the economy mode in their car, that is if you have that feature.

Many years ago we had a Mondeo and found using it in Eco mode it was constantly changing gear which probably used more fuel.

We have the feature on the Jeep, but have never used it preferring to use the normal mode as most times the Jeep is used for long distant motorway traveling. Not sure if there will be any real benefit switching to the Eco mode to save perhaps a small drop of fuel every tank full?

 

[Beachball]

Many years ago we had a Mondeo and found using it in Eco mode it was constantly changing gear which probably used more fuel.

We have the feature on the Jeep, but have never used it preferring to use the normal mode as most times the Jeep is used for long distant motorway traveling. Not sure if there will be any real benefit switching to the Eco mode to save perhaps a small drop of fuel every tank full?

When we were towing we use the eco mode all the time and we got more to gallon than normal mode