Few more words on edible oil as a fuel

What's the MPG like? Can I use chip fat and veggie oil? What about LPG?

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Eilheart
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Few more words on edible oil as a fuel

Post by Eilheart » Wed Feb 03, 2021 9:13 am

Is it technically possible and sensible to use edible oil as a fuel for cars? The shortest answer is yes, but under the right conditions.

To begin with, we need to distinguish between two ways of doing things. The first is to produce the methyl ester of this oil. In a nutshell, it consists of precipitating about 20% of glycerine contained in edible oil and giving it properties similar to mineral diesel. The process is chemically uncomplicated, and small "home" installations are available for this purpose. Such diesel fuel (the so-called biofuel) is absolutely equivalent to mineral diesel fuel, and for several years it has been a 5% or more addition to commercial diesel fuel. There are also some "BIO 100" fuels on sale, i.e. one hundred percent biofuel for types of diesel (economic conditions that result in such an offer is a topic for a separate story). In any case, edible oil esters (in our case, if made from rapeseed oil, they have the international name "RME"), can be used interchangeably in practically all types of diesel engines, especially in modern ones, because they are adapted to this use. This adaptation only involves the use of seals and rubber and plastic parts in the fuel system, which do not react with this fuel. The only limitation is to avoid long, months-long storage of the biofuel, which can decompose over time.

But let's look at the second use of edible oil, which is to use it directly as diesel fuel. Is this possible? Yes. Edible oil is good diesel fuel, even though it has quite different physical and partly chemical properties from mineral diesel. The most important differences from our point of view are as follows:

edible oil has several to several percent lower heating value (relative to volume)
edible oil has a significantly higher viscosity
heating oil has a much higher flash point (over 200 degrees Celsius)
heating oil has a slightly lower cetane number (a parameter determining the self-ignition capacity of fuel mixed with air and injected into the combustion chamber).

So here you go. It is possible. Would I do it? No, no I wouldn't.
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mikeonb4c
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Re: Few more words on edible oil as a fuel

Post by mikeonb4c » Wed Feb 03, 2021 11:36 pm

Eilheart wrote: Wed Feb 03, 2021 9:13 am Is it technically possible and sensible to use edible oil as a fuel for cars? The shortest answer is yes, but under the right conditions.

To begin with, we need to distinguish between two ways of doing things. The first is to produce the methyl ester of this oil. In a nutshell, it consists of precipitating about 20% of glycerine contained in edible oil and giving it properties similar to mineral diesel. The process is chemically uncomplicated, and small "home" installations are available for this purpose. Such diesel fuel (the so-called biofuel) is absolutely equivalent to mineral diesel fuel, and for several years it has been a 5% or more addition to commercial diesel fuel. There are also some "BIO 100" fuels on sale, i.e. one hundred percent biofuel for types of diesel (economic conditions that result in such an offer is a topic for a separate story). In any case, edible oil esters (in our case, if made from rapeseed oil, they have the international name "RME"), can be used interchangeably in practically all types of diesel engines, especially in modern ones, because they are adapted to this use. This adaptation only involves the use of seals and rubber and plastic parts in the fuel system, which do not react with this fuel. The only limitation is to avoid long, months-long storage of the biofuel, which can decompose over time.

But let's look at the second use of edible oil, which is to use it directly as diesel fuel. Is this possible? Yes. Edible oil is good diesel fuel, even though it has quite different physical and partly chemical properties from mineral diesel. The most important differences from our point of view are as follows:

edible oil has several to several percent lower heating value (relative to volume)
edible oil has a significantly higher viscosity
heating oil has a much higher flash point (over 200 degrees Celsius)
heating oil has a slightly lower cetane number (a parameter determining the self-ignition capacity of fuel mixed with air and injected into the combustion chamber).

So here you go. It is possible. Would I do it? No, no I wouldn't.
Welcome, and an interesting post. I used rapeseed oil in a 25% ratio with diesel for a while in summer months when i first got the Bongo. That was 15 years ago when the price saving was very significant. If anything the engine seemed to run a bit better, and i had no issues with blocked fuel filter or seals. I guess my question is - if the price differential were still significant and given what I have described, would you use rapeseed oil (the least viscous i found) in some proportion with diesel?
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willow2u
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Re: Few more words on edible oil as a fuel

Post by willow2u » Thu Feb 04, 2021 12:03 am

A few people I knew a while ago were running on old cooking oil because they could get hold of it for nothing I always found it really weird that this ex chip and burger oil would make a car run
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Re: Few more words on edible oil as a fuel

Post by Ashely_Davis » Thu Feb 04, 2021 2:31 pm

I didn't try to use edible oil as a fuel. I don't want to cause a bigger problem and it will cost me more in the end.