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# Wood Chip Powered Automobile

Carbon-Neutral and smells of grandmas fireplace
 (+6, -7) [vote for, against]

Ok, the car's trunk basically holds a hopper full of wood-chips. The chips run along a conveyer to a burner/generator that produces electric power. This keeps a set of oh lets say 20 kwh batteries charged while also powering the main electric motor. We shove in some super capacitors for a speedy take off and Bob is your mother's brother.

The generator would ideally be a Stirling engine, but could also maybe be a simpler ICE.

Fuel usage? Well wood-chips pack about 10 MJ per kilogram, and assuming our gross energy usage is about 1 kwh/km, we're talking about 350 g per km or 35 kg per 100 kms. For you imperial boys thats about 1.24 lbs per mile or 0.80 miles per lb of chips. So not too bad.

 — DrWotsit, Jun 09 2007

Gengassidan http://www.gengas.nu/byggbes/index.shtml
"Construction of a Simplified Wood Gas Generator for Fueling Internal Combustion Engines in a Petroleum emergency" [afinehowdoyoudo, Jun 10 2007]

Wood gas http://en.wikipedia.org/wiki/Wood_gas

Stanley Steamer http://en.wikipedia...iki/Stanley_Steamer
I distinctly remembering my grandpa telling me that these things could burn wood. [bungston, May 14 2008]

 Standard gasoline has an average weight of 6.216 pounds per gallon... so... if your car gets an average of 30 miles to the gallon, you've got 4.826 miles to the pound...

 just to see side by side:

 Gasoline: 4.826 mi/lb Wood Chips: 0.80 mi/lb

 and the wood chips would smoke like crazy, although it would be carbon neutral.

BUT, it would indeed smell like grandma's fireplace :)
 — CaptainClapper, Jun 09 2007

I thought that it was Brian?
 — skinflaps, Jun 09 2007

I'd rather burn up all the Earth's oil than all of the Earth's trees. [-]
 — nuclear hobo, Jun 09 2007

Surely you mean an external combustion engine? Unless you're evaporating methanol out of the wood to use as fuel.
 — discontinuuity, Jun 09 2007

 Actually, Bob is my dads uncle (my grandpa's brother?).

I saw on a cable television show someone that put a big wood chip smoker thing on the back of their Suzuki, and piped the gases into the inlet of the engine where they then burned.
 — BJS, Jun 10 2007

 Is that Smith and Jones or Alas Smith and Jones?

-nothing new here.
 — zeno, Jun 10 2007

This was popular during WW2, via a system known as 'Gengas' or 'producer gas'. (see links) Incomplete combustion of wood produces a mix of combustible gasses, mainly carbon monoxide, which can fuel an IC engine. There are drawbacks to the gengas scheme: the toxicity of CO, keeping the fire burning under all circumstances, inability of using tar-laden softwoods, filtration required to remove corrosive gasses, reduced power output of a given engine displacement compared to gasoline, wasted energy in the heat output of the gasifier.... but it works. I like your idea of a Stirling engine to directly utilize the heat from wood fire, but it is, dare I say, halfbaked. A bun nonetheless!
 — afinehowdoyoudo, Jun 10 2007

A Rankine cycle (steam engine or steam turbine) might be a better bet for your generator than a Stirling engine. Pity about the working fluid, but the power density is way better.
 — afinehowdoyoudo, Jun 10 2007

I feel like this idea takes us technologically backwards. I think solar and renewable technologies will be come efficient enough to negate combustion engines all together, or all non-turbine engines.. because I love the concept of turbine engines for some reason. they make me smile.
 — twitch, Jun 10 2007

 I like the idea of a turbine hybrid engine. I wonder why this hasn't been done. It would be nice to have a car that could run on practiacally any fuel (Including wood gas).

 //steam turbine) might be a better bet for your generator//

You have to have superheated steam for that - that's why steam turbines are mostly confined to power plants.
 — nomocrow, Jun 10 2007

 Baked as a fuel in and of itself. In fact, baked in order to become a fuel, ha ha.

 Hybrid drivetrain is also not new. Combining them is new, but new enough?

Adding the Stirling engine, though, gets my bun regardless. Stirlings are awesome.
 — elhigh, Jun 14 2007

Not to sidetrack, but: Cars are now being developed that run on compressed air. And they seem practical. You don't have to burn anything.
 — Ander, Jun 14 2007

//Cars are now being developed that run on compressed air//
Oh dear.
Compressed air is possibly the most expensive form of stored energy available, and the idea of a compressed air vehicle is about as old as... well, something really, really old.

I didn't know it was so expensive.
 — BJS, Jun 15 2007

 with compressed air, i guess, theoretically, upkeep/maintenance would be reduced. I'd put my money on ultracapacitors and lithium.

It's hard to make a comparison because technology keeps on moving in this field. faster than normal? I don't know.
 — twitch, Jun 15 2007

 //run on compressed air. And they seem practical. You don't have to burn anything//

That's true. Air compresses itself for our benefit just to be nice.
 — nomocrow, Jun 15 2007

 Airmotor driven vehicles have been around. I saw a really old, scratchy B&W film showing a prototype from, I think, the thirties. Nothing came of that.

 I like this new French concept, in that they're adopting the biberronage (sp?) approach to short, frequent recharges that make a shortrange city car practical. Also, you can't fault using the low-temp exhaust for chilling an AC heat exchanger.

Hey, here's a thought: a typical airtight woodstove produces exhaust similar to the gengas in this concept. Run that exhaust through an engine-generator to extract the maximum fuel value from the flue gases. Pipe the cooling water from around the engine through a heat exchanger in a big hot water storage tank. That'd make it a gengas co-cogen system. Fuel it with coconut husks: coco gengas co-cogen. Oy.
 — elhigh, Jun 15 2007

 Bring back woodgas cars now. They have a real decadent, dystopian feel. Peak Oil is here anyways!!

Like it.
 — django, Jun 15 2007

There have got to be more efficinet ways to power a car...lol.
 — colinwheeler, Jun 16 2007

 ...like taking an ocean ecosystem, having it all die and sink to the sea bed, burying it, fossilising it all beneath a layer of rock maybe a mile thick, waiting for an extremely long time for it to form oil, drilling through said rock via a drill mounted on a floating platform weighing thousands of tonnes, pumping it out into a ship which can carry a quarter of a million tonnes of the stuff, shipping it halfway round the world, heating it all, separating it out by molecular weight, transporting it across country by road, rail or pipeline, and finally burning it in your engine?

If you're after simple and easy, locally-grown wood chips are much better when the whole lifecycle is taken into account.
 — david_scothern, Jun 16 2007

Keep in mind that this is truly carbon-neutral only if the fuelwood is grown & harvested on a cycle of no more than a few years. Burning old trees is a release of stored carbon as CO2.
 — afinehowdoyoudo, Jun 17 2007

I like the steampunk potential of a woodgas hybrid. Trunk full of nanotech lithium ion batteries, sleek bodyshell with sophisticated electronics under the hood, and a big, badass black smokestack projecting out of the right front fender. Yeah.
 — elhigh, Jun 19 2007

 [elhigh], throw some Swiss Miss in the boiler and add a spigot; you'd have a coco gengas co-cogen cocoa generator!

 Sorry, all, couldn't help myself...

Also: WOOT! Go steampunk!
 — RunnerPack, Oct 17 2007

 I like this idea with the alternative of wood chips - dry leaves!

 Just blaze a trail across the meadows during fall and have an articulated airflow-assisted dry-leaves scoop at the car's underside ready.

And, tour the countryside neighborhood with the banner: "line up UR mower clippings by D roadside 4 free pickup on my way home/work"
 — rotary, May 14 2008

 I wonder how emissions laws would apply to a steam powered vehicle? I love the idea of 21st century technology and a steampowered car.

I never really understood why the steam could not be reclaimed as water, at least to some degree.
 — bungston, May 14 2008

Yes, it could run on 'shit', literally or figuratively: anything that burns. It doesn't have to be chopping down old-growth forests for fuel. There's plenty of materials going to 'waste' that will end up burning anyway, that could go to fuelling our motoring habits. The impact would depend on how much, & what, gets burnt.. details matter, eh. [bungston], emissions laws could be applied in exactly the same way: CO, NOx, and HC are the same pollutants, regardless of fuel. Generally speaking, steady-state, external combustion has the potential to burn cleaner than internal, intermittent combustion.. but it depends on fuel: the variety of HC's (unburned hydrocarbons) that could be produced is multifarious. Oh, &, the steam could be recycled into feedwater, by means of a condenser. Aaanyway.. before I "invoke Vernon".. steampunk out
 — afinehowdoyoudo, May 15 2008

 From an efficiency standpoint (as opposed to half-baked), collecting all the trees, turd, grass and bodies-that-gotsta-disappear, and burning them in a power-plant scale turbine would work best.

 Use the electricity generated to charge electric vehicles.

Best systems, weed-to-wheel, would yield almost 50% efficiency.
 — TIB, May 15 2008

Nox and Sox and unburnt particulates might be absorbed in the steam reclaimer. They would concentrate in the water which would acidify it. It would be a different disposal problem (a tank of acid and soot) but could keep the air cleaner.
 — bungston, May 15 2008

 afinehowdoyoudo, I know this is a bit late :) but many of the problems you mentioned with wood gasfiers have been solved in the GEK gasifier designed by ALL Power Labs.

 The GEK gasifier recycles nearly all of the "waste" heat of the syngas, using it to preheat the air and the biomass that's used to make the syngas.

 The GEK gasifier can burn softwoods perfectly well. Some of the tars are burnt for heat which is used to preheat air and biomass, some of the tars are chemically reduced as they pass through the glowing hot charcoal, and become non-tarry gaseous fuel, and the remainder of the tar is captured in a filter.

 The GEK gasifier is designed so that the generated gas is kept at sub-atmospheric pressure in between itself and the engine that it is fueling. This means that if there's a leak, it will be a leak of air moving inwards, not a leak of poisonous CO moving outwards.

 I don't think I need to describe exactly how poisonous and explosive gasoline is, do I?

 A gasifier doesn't need to be kept running *all* the time, but does need a 15-30 minute warmup. I'll admit this isn't trivial, but the nuisance factor could be reduced if a remote start system were added.

 And as for reduced power compared to gasoline, that's only if you leave the compression ratio alone. Wood gas is highly resistant to knocking/pre-detonation, and if you increase the compression ratio to that typical of a diesel engine, the power goes up to what you'd expect of gasoline in an unmodified engine.

 elhigh, a wood gas vehicle would not have a smokestack, since all particulates (aka smoke) are removed by filters after the gas leaves the gasifier, and before it enters the engine.

 Next, a well designed airtight wood stove will have very little in the way of carbon monoxide in the exhaust, since it will have all been burnt before leaving the stove!

 Also, a well designed gasifier will have significant quantities of hydrogen in the produced gas, and a stove's exhaust won't have any.

 This happens in a gasifier because the water vapor produced as the biomass dries is routed downwards through a bed of glowing hot charcoal, which chemically reduces the steam into hydrogen and carbon monoxide.

Nothing resembling this reaction occurs in a wood stove... all the combustion products move upward!
 — goldbb, Jan 29 2013

I heard that the University of Madrid built a prototype of a woodburning car. Apparently, it gets up to 370 miles per Spanish Galleon.
 — AusCan531, Jan 29 2013

My grandfather had a charcoal burner on his car in WWII. This idea is baked to a crisp.
 — UnaBubba, Jan 29 2013

 Wood dust (or some sort of slurry) could be burnt in a Diesel engine, using air-blast injectors. It would have to be a low- revving unit and ash might be a problem, as might lubricants.

 In a hybrid scheme, a small Diesel running at a constant speed to charge battery packs would be a way to go.

Wood gasifier vehicles are Widely Known To Exist.
 — 8th of 7, Jan 29 2013

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