alcohol diesel

I was told that a quick fix to prevent diesel fuel purchased in the summer from gelling in the winter was to add a small amount of kerosene. Maybe gasoline is also suitable. But I am not an automotive mechanic, nor a chemist so please don't rely on just my information. I do know that the blend of hydrocarbons sold as diesel fuel gets seasonally changed to prevent gelling.

There must not be much potential, or someone would have already done it.

Diesel has more specific energy per unit than either gas or alcohol, why dilute it and lower the energy content?

Because the diesel fuel distributed in the summer becomes overly viscous, or gelled in freezing temperatures. Paraffin has even more energy per unit, but a candle won't get through the injector and into the cylinder. Many distributors sell additives to prevent this gelling. Naturally diesel fuel sold in a frigid climate must have an additive or it won't get pumped out by the filling station pumps.

Sure. I understand the viscosity/shear issues. I thought the OP meant "why not do it all the time.

Hell, I don't understand 90% of the questions here anyway. Maybe I didn't understand this question either.

Adding strait gasoline to diesel fuel is a bad idea. Gasoline tends to make for very hard knock from its far more rapid detonation rate. In very limited quantities (under a few percent) its not a problem but it wont effectively un gel diesel at that low of ratios.

Ethanol works well as has been used by many using biodiesel since its also an organic based fuel. I have use E85 to thin out used oil so it will run in my small diesel engine. Around 20% or less seems to work well enough.

But still it depends on what quality of fuel and what compression ratios your engine runs on to find the most favorable ratio to use.

When dealing with the odd fuel sources what works well for one person in one application can be completely wrong in another so take that into account as well.

TCMTECH Guru, No, petrol or alchohol, does not make a diesel engine knock; To much "gasoline" added to diesel will, because of lack of lubrication, cause wear of the pump etc.

10% petrol added to diesel will cause less knocking when starting a very cold engine and do more good than harm.[Depending on what has already been added when you buy it]

Only add petrol to diesel if the glow plugs, starting system, etc is in good order and you have hard starting or exessive knocking [When old engine's compression is too low]

Jurie

I have done it while experimenting and I know for a fact the gasoline we have around creates horrible knocking on the diesel engines I have tried it on. The E85 works fine up to a limit though which is why I do on occasion use it to thin out fuels ifI don't have the correct additives around.

Perhaps with some engines it may handle it better but my experience has gave me strong concerns to never use it as a fuel thinner to any extent with my engines.

As a mechanical engineer with experience with diesel engines, I can assume you it is not a good idea to add too much petrol to diesel. Petrol has anti-knock properties to prevent premature ignition of the fuel before the spark. Diesel engines require near instant ignition of the fuel upon injection. If this does not occur, a significant amount of fuel will accumulate in the cylinder and the result is a rapid rate of pressure increase. This is audible as knock and can have severe effects on bearings and other components. When a diesel engine is idling the internals of the cylinder are cooler than under high load, so the lag before ignition of the fuel is longer and it is heard as knock.

Severe knock can also occur in petrol engines, if the engine tuner gets too carried away with compression ratio and high speed detonation occurs at high load. This can destroy maain and/or big end bearing in minutes (I know someone who did it several times on the same engine - a slow learner).

Dilute your diesel with care (kerosine may be safer than petrol).

I accidently added diesel to a a gas powered car. The car started and ran, but had almost no power and knocked its heart out. After driving for about 200 miles to burn off the mixture, I added pure gas and the car seemed to be no worse for its ordeal, but I never told the people I rented the vehicle from, so I can't comment on any long term effects. Given a choice, I wouldn't burn diesel in my own car. It has a 0 octane rating.

look at the old tractors, such as early john deere. They were designed to operate on distillate, a crude form of diesel, but used gasoline to start and warm up.

Many older diesel manuals, mercedes,etc, tell you it is ok to add 5-10% regular fuel to the diesel for winter use. Do not go above 10%, as engine damage may result. 5% is about all you want with newer engines. I have also heard in another thread about 5% diesel is good for gas cars.