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Correct me if I'm wrong, but I don't think it would be feasible to move all or most cars in the US to use diesel. Diesel, gasoline, and jet fuel are all petrole

Correct me if I'm wrong, but I don't think it would be feasible to move all or most cars in the US to use diesel. Diesel, gasoline, and jet fuel are all petroleum distillates that boil off at different temperatures. So each barrel of oil contains so many units of gasoline, so many units of diesel, and so many units of jet fuel/kerosene/mineral oil/whatever. And I believe that you get much more gasoline out of a barrel of oil than you get diesel, so moving many cars over to diesel would actually increase oil consumption it seems.

dperny 12y ago
Diesel isn't a fuel type, it's an engine type. What we call "diesel fuel" is really just fuel better suited for burning in a diesel engine than gasoline. We also have techniques for refining some hydrocarbon chains into different ones, which means we can focus production on one fuel type.
- mnw21cam 12y ago
  The engines are designed quite specifically for the type of fuel that will be burned in them. Although technically you could make a diesel engine that would burn normal petrol, it would not be advisable to put normal petrol in a diesel car, because the engine relies on the fact that diesel is a better lubricant than petrol. Also, various components (such as fuel filters, fuel pumps, etc) also depend on the fuel being of a certain type, and would be damaged or otherwise fail to work with the wrong fuel.
  - jacquesm 12y ago
    The bigger problem (other than lubrication) is managing the moment of detonation. Petrol would explode way too early in the cycle of injection, that's why it will damage a diesel engine. s/compression/injection/
    - auxym 12y ago
      In a diesel engine, only fresh air is in the cylinder during the compression cycle. At the top of the compression cycle, that's when the fuel starts to be injected and immediately burns/explodes. There's other reasons why petrol in a modern diesel engine wouldn't work, but i don't think pre-ignition/detonation is one of them. "Throttle" in a diesel actually controls for how long the injection takes place.
      - jacquesm 12y ago
        Yes, that's all correct. But the fuel injected does not detonate immediately, it is allowed to spread out a bit and the chambers are shaped to channel the detonation. It's a short interval but it is an interval. Injecting gasoline at those pressures and temperatures would mean instantaneous detonation of the fuel injected, too early in the cycle which will cause damage (to the injector, and to the crankshaft and/or pushrod bearings because they'll have to deal with more force than what they were designed to cope with because the energy is liberated in a much shorter time-frame). At best this will cause severe degradation of engine life, at worst immediate failure. Another issue is that the injectors are carefully shaped to deliver a mist of fuel and the properties of gasoline and diesel are sufficiently different that the droplets will be of the wrong size and won't separate cleanly from the injector before detonation occurs. All in all, not something you want to experiment with so if you find that you've 'gassed up' your diesel vehicle better drain the tank instead of taking your chances. In winter in Canada it is common to put about 5% gasoline in the diesel fuel to overcome temperature effects on the diesel fuel.
- patfla 12y ago
  Diesel is a different mix of longer carbon chains than gasoline and I'd think that makes it a different fuel type.
Havoc 12y ago
Nope...pretty sure its not a question of diesel OR petrol. I don't know the chemical details, but thats what I deduce by the pricing and availability of diesel everywhere else.
ams6110 12y ago
Used to be this way. Diesel used to be something of a waste product from refinining gasoline. As a result it was both somewhat dirty and also cheaper than gasoline. Today, refining technology and hydrocracking allows a barrel of oil to be refined almost completely into whatever end product the refiner wants. Diesel, kerosene, jet fuel (which are all pretty much the same thing actually) or gasoline. So now these refined products are priced more by their energy content which is why the pricing has flipped and diesel now costs more per gallon than gasoline (but can still be more economical overall).
- ptaipale 12y ago
  > Diesel used to be something of a waste product from refinining gasoline It depends, but anyway it's more certain that originally gasoline was a waste product from refining lamp oil (which is closer to diesel).
- joshuapants 12y ago
  I see, thanks for correcting me!
- e12e 12y ago
  There didn't use to be any "diesel fuel", Diesel designed his engine to work on plant oils and other renewable (for some value of renewable that's better than gasoline, but more at odds with food production). The oil industry realized that they could also produce something that could fuel diesel engines, and they called it diesel fuel. Modern diesel engines are very different -- but for eg. industrial and military use, you'll still see some resilient engines that can burn pretty much anything you throw at them, from butter to diesel fuel. Shame he fell of a boat in the English channel and drowned.
  - cwyers 12y ago
    You can fuel a Humvee with JP-8, which is jet engine fuel. It's been a long time, but I remember there being problems if you switched fuels -- if you had been using regular truck diesel and switched to JP-8 you could have engine problems because you'd still have some residual truck diesel mixing with the JP-8.
maxerickson 12y ago
The output mix won't have an enormous impact on the amount of energy extracted from a barrel. US refineries operate crackers to increase the amount of gasoline in their output: http://en.wikipedia.org/wiki/Fluid_catalytic_cracking http://en.wikipedia.org/wiki/Fluid_catalytic_cracking
blacksmith_tb 12y ago
It might demand greater production, but the higher efficiencies of diesel engines would mean less of what was refined would be needed for transportation (admittedly not perfect). And we would have to find something to do with all that surplus gasoline... which makes biofuels look more appealing (I run B50 or B99 in my VW, depending on the season), or better yet, using solar power to synthesize diesel fuel.
ptaipale 12y ago
Oil refineries are nowadays complex factories that convert crude oil into lots of different distilled products. When you process a barrel of crude oil, you're not restricted to some proportion of gasoline, some proportion of kerosene and diesel and whatever. You can basically turn it up to produce more gasoline, or more diesel fuel, or whatever. The losses aren't significantly different. You can get more gasoline out of a barrel of oil, but you can also get more mileage out of a litre of diesel than litre of gasoline. Diesel has higher energy content. What's more, diesel fuel can be made from biological materials as well. In fact, we have had people drive their diesel cars with discarded frying oil used in hamburger restaurants to make fries. You have to filter it, and you won't make the current EU emission standards, but for moving a vehicle, it works all right. Whether it is feasible to move all or most cars in the US to use diesel is then another matter. Diesel engines are a bit noisier, for instance, so someone might object that. But the everyday driveability of a car with diesel engine, particularly a modern one with turbo, is nice. Lots of torque on low rpm's so it's easy to drive.

dperny 12y ago

Diesel isn't a fuel type, it's an engine type. What we call "diesel fuel" is really just fuel better suited for burning in a diesel engine than gasoline. We also have techniques for refining some hydrocarbon chains into different ones, which means we can focus production on one fuel type.

mnw21cam 12y ago
The engines are designed quite specifically for the type of fuel that will be burned in them. Although technically you could make a diesel engine that would burn normal petrol, it would not be advisable to put normal petrol in a diesel car, because the engine relies on the fact that diesel is a better lubricant than petrol. Also, various components (such as fuel filters, fuel pumps, etc) also depend on the fuel being of a certain type, and would be damaged or otherwise fail to work with the wrong fuel.
- jacquesm 12y ago
  The bigger problem (other than lubrication) is managing the moment of detonation. Petrol would explode way too early in the cycle of injection, that's why it will damage a diesel engine. s/compression/injection/
  - auxym 12y ago
    In a diesel engine, only fresh air is in the cylinder during the compression cycle. At the top of the compression cycle, that's when the fuel starts to be injected and immediately burns/explodes. There's other reasons why petrol in a modern diesel engine wouldn't work, but i don't think pre-ignition/detonation is one of them. "Throttle" in a diesel actually controls for how long the injection takes place.
    - jacquesm 12y ago
      Yes, that's all correct. But the fuel injected does not detonate immediately, it is allowed to spread out a bit and the chambers are shaped to channel the detonation. It's a short interval but it is an interval. Injecting gasoline at those pressures and temperatures would mean instantaneous detonation of the fuel injected, too early in the cycle which will cause damage (to the injector, and to the crankshaft and/or pushrod bearings because they'll have to deal with more force than what they were designed to cope with because the energy is liberated in a much shorter time-frame). At best this will cause severe degradation of engine life, at worst immediate failure. Another issue is that the injectors are carefully shaped to deliver a mist of fuel and the properties of gasoline and diesel are sufficiently different that the droplets will be of the wrong size and won't separate cleanly from the injector before detonation occurs. All in all, not something you want to experiment with so if you find that you've 'gassed up' your diesel vehicle better drain the tank instead of taking your chances. In winter in Canada it is common to put about 5% gasoline in the diesel fuel to overcome temperature effects on the diesel fuel.
patfla 12y ago
Diesel is a different mix of longer carbon chains than gasoline and I'd think that makes it a different fuel type.

Havoc 12y ago

Nope...pretty sure its not a question of diesel OR petrol. I don't know the chemical details, but thats what I deduce by the pricing and availability of diesel everywhere else.

ams6110 12y ago

Used to be this way. Diesel used to be something of a waste product from refinining gasoline. As a result it was both somewhat dirty and also cheaper than gasoline. Today, refining technology and hydrocracking allows a barrel of oil to be refined almost completely into whatever end product the refiner wants. Diesel, kerosene, jet fuel (which are all pretty much the same thing actually) or gasoline. So now these refined products are priced more by their energy content which is why the pricing has flipped and diesel now costs more per gallon than gasoline (but can still be more economical overall).

ptaipale 12y ago
> Diesel used to be something of a waste product from refinining gasoline It depends, but anyway it's more certain that originally gasoline was a waste product from refining lamp oil (which is closer to diesel).
joshuapants 12y ago
I see, thanks for correcting me!
e12e 12y ago
There didn't use to be any "diesel fuel", Diesel designed his engine to work on plant oils and other renewable (for some value of renewable that's better than gasoline, but more at odds with food production). The oil industry realized that they could also produce something that could fuel diesel engines, and they called it diesel fuel. Modern diesel engines are very different -- but for eg. industrial and military use, you'll still see some resilient engines that can burn pretty much anything you throw at them, from butter to diesel fuel. Shame he fell of a boat in the English channel and drowned.
- cwyers 12y ago
  You can fuel a Humvee with JP-8, which is jet engine fuel. It's been a long time, but I remember there being problems if you switched fuels -- if you had been using regular truck diesel and switched to JP-8 you could have engine problems because you'd still have some residual truck diesel mixing with the JP-8.

maxerickson 12y ago

The output mix won't have an enormous impact on the amount of energy extracted from a barrel. US refineries operate crackers to increase the amount of gasoline in their output: http://en.wikipedia.org/wiki/Fluid_catalytic_cracking http://en.wikipedia.org/wiki/Fluid_catalytic_cracking

blacksmith_tb 12y ago

It might demand greater production, but the higher efficiencies of diesel engines would mean less of what was refined would be needed for transportation (admittedly not perfect). And we would have to find something to do with all that surplus gasoline... which makes biofuels look more appealing (I run B50 or B99 in my VW, depending on the season), or better yet, using solar power to synthesize diesel fuel.

ptaipale 12y ago

Oil refineries are nowadays complex factories that convert crude oil into lots of different distilled products. When you process a barrel of crude oil, you're not restricted to some proportion of gasoline, some proportion of kerosene and diesel and whatever. You can basically turn it up to produce more gasoline, or more diesel fuel, or whatever. The losses aren't significantly different. You can get more gasoline out of a barrel of oil, but you can also get more mileage out of a litre of diesel than litre of gasoline. Diesel has higher energy content. What's more, diesel fuel can be made from biological materials as well. In fact, we have had people drive their diesel cars with discarded frying oil used in hamburger restaurants to make fries. You have to filter it, and you won't make the current EU emission standards, but for moving a vehicle, it works all right. Whether it is feasible to move all or most cars in the US to use diesel is then another matter. Diesel engines are a bit noisier, for instance, so someone might object that. But the everyday driveability of a car with diesel engine, particularly a modern one with turbo, is nice. Lots of torque on low rpm's so it's easy to drive.