why no vehicle that alternates between diesel and gas?

[roscoe]

This seems like the perfect MadMax vehicle solution. I am aware that the ignition systems are different, but what is the real limitation here? Compression ratios? Differences in the torque curve for the transmission gearing? Some vehicles have two spark plugs per cylinder - there is no reason you couldn't have one spark plug and one glow plug. There would have to be different fuel injectors for each system, and two fuel tanks, but I wonder if there is some other constraint that has prevented it. You see LPG and gas, but never diesel and gas.

[TacAir]

M-35 multifuel engine runs eithe or and a mix.

Old tech

[dukman]

I thought I had heard about someone tinkering on this, but more of a hybrid idea with two separate engines. He was going to use an old FWD Toronado front end for the gas, and mid-mount the diesel behind the driver. I heard about this a couple years ago on a different forum, so I don't know if the project ever amounted to anything.

[Grey Mann]

The compression ratio required to ignite diesel fuel would call for gasoline to have literally off-the-charts octane levels to prevent detonation. They're simply too different to really work.

That said, you can cut fuels with gasoline to stretch the supply with many multifuel or diesel engines.

[raptor]

Gas turbines can run on a wide variety of fuels.

[ZombieSoldier01]

compression ratios, rpm ranges (diesels generally dont go over 3600 rpms) nad a few other little things

[CiggsWar]

The compression of of a vechile is around 9 :1 for gasoline and around 20:1 for diesel, it takes that much heat to burn diesel fuels, the other difference is the carbon chain- C7H16 through C11H24 for gas and while diesel fuel is typically C14H30. The cracked carbon chains of gas to get hydrocarbon chains of different lengths from a low to a high to get octane mixes. It takes less refining to process diesel fuel.
heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio. If you to put that in a diesel it would knock and over heat the dentonation occurs too rapid exploding.
gas ignites fast 125,000 BTU, diesel burns at 147,000 BTU making the diesel more efficient at burning more of the fuel mix.
Gas engines are wasteful compared to diesels.

There has been innovation that were scraped back in the latter 60's GM came out with a sand block engine that could handle the heptane as in heat and had efficiency and ever long lasting, never happened and became a myth. There are thousands of innovations that are scraped bought out.
You will never see a better way of life in our current ignorances.

[run faster]

I was going to say something but that was settled pretty quickly

[Hoppy]

I was going to say something but that was settled pretty quickly

yup. most any military vehicle built in the last few decades will run off most anything the burns
gas
diesel
biodeiesl
ethanol
jet fuel/ kerosene
first morning piss of an alcoholic...


hybrids are old news, and only got lamer.

[LBB]

Gas turbines can run on a wide variety of fuels.

But they gas mileage sucks.
That's why most tanks have diesel engines and not gas turbines.

[aa1pr]

The method in which the engine uses combustion is different.

[ace of shades]

Tomorrow if I get the chance I will ask a friend of mine how the motor on his grader works. It runs off of diesel but starts off of gas. Its not a pony motor either, it actually has gas going into a piston when it starts and some how swaps over to diesel. I'm not certain on how it works, but when I find out I will update and edit this post


[edit] When I got back into town tonight I asked my buddy how it worked. Basically it was a diesel motor, but instead of using glow plugs it uses spark plugs and about a gallon of gas. You run the thing all most out of gas and you pull this big ass lever that turns on the injector pump. While its burning gas it heats up the cylinders and then runs off of that head instead of using glow plugs.. depending on what side of the roadgrader you're standing on you hear "this things GAS!?" No its diesel "well its got spark plugs too" [/edit]

[LBB]

A multifuel engine works like a diesel engine.
The problem is, that it has to be stronger than a normal diesel engine, because some fuels will burn stronger.

So over all, a heavier engine would mean you need more power to move the vehicle, and that burns more fuel.

In a time were everybody tries to build lightweight engine this isn't a great idea.

[LBB]

Tomorrow if I get the chance I will ask a friend of mine how the motor on his grader works. It runs off of diesel but starts off of gas. Its not a pony motor either, it actually has gas going into a piston when it starts and some how swaps over to diesel. I'm not certain on how it works, but when I find out I will update and edit this post

It's probably something like this
http://en.wikipedia.org/wiki/Hot_bulb_engine

[Biggin]

Gas turbines can run on a wide variety of fuels.

But they gas mileage sucks.
That's why most tanks have diesel engines and not gas turbines.

But the best tank in the world uses a gas turbine engine.

[LBB]

Gas turbines can run on a wide variety of fuels.

But they gas mileage sucks.
That's why most tanks have diesel engines and not gas turbines.

But the best tank in the world uses a gas turbine engine.

http://armour.ws/the-best-tank-in-the-world/

The Leo 2 has a range of 340 miles with it's internal fuel, while the M1A1 has a range of 265 miles, and this while the M1A1 carries 700 liters more fuel.

There are only 7 countries that use the M1A1 while there are 18 countries that use the Leo 2, so I really don't want to go into this discussion, because this will become political and end in a fight who has the best tank.

There is no such thing as the world best tank, because a single main battle tank can't win a war.

[Jeriah]

The Leo 2 has a range of 340 miles with it's internal fuel, while the M1A1 has a range of 265 miles, and this while the M1A1 carries 700 liters more fuel.

Did some Wiki looking, apparently it's a hair faster, too. (45mph vs. 42). Despite being a V-12, it's multi-fuel as well.

[Crazy Wolf]

Gas turbines can run on a wide variety of fuels.

But they gas mileage sucks.
That's why most tanks have diesel engines and not gas turbines.

But the best tank in the world uses a gas turbine engine.

The best tank is not the best zombie-apocalypse survival vehicle. The best tank in the world has to carry a very big gun and very heavy ammunition to defeat other very big tanks with armor that's almost as big and heavy as the armor on the best tank in the world. The best tank in the world has several concerns that rank much higher than fuel efficiency, and the best tank in the world is backed up by the best supply chain in the world. You, as a survivor of a natural disaster or zombie apocalypse, will not have such a supply chain, and will likely not need to defeat such armor, or defend yourself against 120mm depleted-uranium shells.

[AwPhuch]

The compression of of a vechile is around 9 :1 for gasoline and around 20:1 for diesel, it takes that much heat to burn diesel fuels, the other difference is the carbon chain- C7H16 through C11H24 for gas and while diesel fuel is typically C14H30. The cracked carbon chains of gas to get hydrocarbon chains of different lengths from a low to a high to get octane mixes. It takes less refining to process diesel fuel.
heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio. If you to put that in a diesel it would knock and over heat the dentonation occurs too rapid exploding.
gas ignites fast 125,000 BTU, diesel burns at 147,000 BTU making the diesel more efficient at burning more of the fuel mix.
Gas engines are wasteful compared to diesels.

There has been innovation that were scraped back in the latter 60's GM came out with a sand block engine that could handle the heptane as in heat and had efficiency and ever long lasting, never happened and became a myth. There are thousands of innovations that are scraped bought out.
You will never see a better way of life in our current ignorances.

ding ding ding...different types of combustion principles and how they ustilize the fuels

I really wonder if you could put gasoline in waste oil (after you run it thru a cellulose filter to remove the larger particles and some of the impurites) say a 4 gallons oil to 1 gallon gas if it would work or burn out the injectors or explode, or just smoke like a busted stove

Hmmmm!!
http://www.dieselbombers.com/general-di ... -fuel.html

[lostwithagps]

wood gas could be an option

[MattZF]

A diesel engine has NO spark plugs, they run off compression and use injectors. And the compression ratios are way different.

Sent From my ATRIX using Tapatalk

[PsycoBob]

Diesels can burn a lot of fuels, but most of them are damned near the same. Kerosene/jet-A/diesel are very similar. Kero may kill your IP from lack of lubrication, but a splash of biodiesel will help that. If you want real multifuel capacity, you've got 2 viable choices- buy a M44 series truck with a multifuel engine (M35a2 cargo, M109a3 shop van, etc) or stick a 3-phase electric motor with a variable-speed controller on your BOV. Add 2 3-phase gensets, 1 gas 1 diesel.

You can also get 5-ton trucks with multifuel LDS-465 engines & power steering.

I really wish someone would make a modern version of the Hypercycle engine- especially for generators. CAT(?) does make kinda-sorta bi-fuel units- natural gas supplemented diesel generators that conserve diesel. I'll try to find the link, but I'm not sure how well a 100+kw prime-power constant-speed system can be translated into automotive use.

[moosiah]

Ace , you friend has an old International diesel .. they have extra valves that lower the comp ratio so they can start on gas ..... I have owned several over the years .. they work very well...

[Schnuh330]

@ AwPhuch
I know quite a few guys that run gasoline and wmo blend in their diesels, some as high as a 50/50 blend. The gas thins out the wmo, makes it easier on the fuel pump and injectors. A couple don't even run an inline fuel heater (used to raise temp and lower viscocity).

Also if you want to get better cheaper waste oil filtration look into a wmo/svo centrifuge. Pretty simple idea really, heated waste oil (to eliminate water contamination) goes into a bowl spinning at high speed, the bowl has a lip at the top, the oil gets spun against the bowl sides and all the heavier dirt and debris "sinks" to the sides of the bowl and the clean oil spill out over the lip of the bowl into the outer housing. End result, you get cleaner fuel and don't have to replace expensive filtration media.

As mentioned by others the 2.5ton military trucks run a multifuel engine, capable of running gas diesel kerosene or jet fuel. What wasn't mentioned is that these engines can run just about any flammable liquid, including 100% svo or wmo with no modifications. I'd be careful running any alcohols or solvents at 100% in it though, for fear of damaging gaskets and seals. The engine would run I'm sure, just not sure for how long. Most likely there would be no major parts failure just an f'ed fuel system.

Converting a diesel engine to svo or wmo involves more work than running wmo/svo blended with gas/diesel. You need extra fuel filtration, a fuel tank heater in most cases(climate depends) and an inline fuel heater. Running a blend requires minimal tuning perhaps a few tweaks to fuel pressure and possibly the injectors.

Schnuh.