A novel fuel-injection system achieves 64 mpg

[Morris Minor]

Surely something like this is better than wasting energy lugging around 400lb battery packs. Thoughts?
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http://www.technologyreview.com/energy/24701/?a=f

Monday, March 08, 2010
Ultra-Efficient Gas Engine Passes Test
A novel fuel-injection system achieves 64 miles per gallon.
By Kevin Bullis

Transonic Combustion, a startup based in Camarillo, CA, has developed a fuel-injection system it says can improve the efficiency of gasoline engines by more than 50 percent. A test vehicle equipped with the technology gets 64 miles per gallon in highway driving, which is far better than more costly gas-electric hybrids, such as the Prius, which gets 48 miles per gallon on the highway.

The key is heating and pressurizing gasoline before injecting it into the combustion chamber, says Mike Rocke, Transonic's vice president of business development. This puts it into a supercritical state that allows for very fast and clean combustion, which in turn decreases the amount of fuel needed to propel a vehicle. The company also treats the gasoline with a catalyst that "activates" it, partially oxidizing it to enhance combustion.


_{Efficient exotic: Transonic Combustion put its new fuel-injection technology into this sports car, which weighs about as much as a Toyota Prius hybrid and has similar aerodynamics. It?s not a hybrid, but it gets better gas mileage than a Prius.}

The technology is one of many being developed to squeeze more efficiency out of existing engines to meet new fuel economy standards and other regulations--without making vehicles more expensive. "It's a time of renaissance for internal combustion engines," says William Green, a professor of chemical engineering at MIT. Improvements include smaller engines boosted with turbocharging, improved valve timing, and direct injection, in which fuel is injected directly into the combustion chamber rather than into an adjacent port. He says Transonic's approach "may be a promising way to improve on conventional direct injection."

If it works as promised, the new technology would improve fuel economy by far more than these other options, some of which can improve efficiency on the order of 20 percent. It is expected to cost about as much as high-end fuel injection systems currently on the market, Rocke says.

Transonic's injection system varies from direct injection in two ways: it uses supercritical fluids and doesn't require a spark to ignite the fuel. The supercritical fluid mixes quickly with air when it's injected into the cylinder.

Once the fuel is injected into the piston, the heat and pressure are enough to cause the fuel to combust without a spark (similar to what happens in diesel engines), which also helps provide fast, uniform combustion. Ignition can be timed to happen just when the piston is reaching the optimal point, so it can convert as much of the energy in the gasoline into mechanical movement as possible, without wasting energy by heating up the combustion chamber walls, as happens in conventional technologies. The company has developed proprietary software that lets the system adjust the injection precisely depending on the load put on the engine.

The system can also reduce something called "throttling losses." Ordinarily, the air intake to an engine is partially closed during cruising, and this makes the engine work harder. Transonic's system can operate with the air intake open, creating a lean mixture in the combustion chamber (with a lot of air, but just a little gasoline). Rocke says that at a steady cruising speed of 50 miles per hour, the test car gets 98 miles per gallon.

The company has demonstrated the technology in its own test engine, and says it is currently testing it with three automakers. One key question is the impact the high pressures and temperatures will have on how long the engine lasts, Rocke says. The company, which is supported by venture-capital investments from Venrock and Khosla Ventures, plans to manufacture its system itself, rather than licensing the technology. It plans to build its first factory in 2013, and to introduce the technology into production cars by 2014.

[Galaxy]

GM, and Mercedes have been working for years on self combusting gasoline engines, and they are still years away from production. So I am a bit skeptical that a startup can solve these problems.

Most of the other technologies they talk about are already on the market.

[mzziaz]

GM, and Mercedes have been working for years on self combusting gasoline engines, and they are still years away from production. So I am a bit skeptical that a startup can solve these problems.

Most of the other technologies they talk about are already on the market.

Diesotto ftw!

[r0tor]

I've seen preheating fuels for increased efficiency used in the power industry for years now... seems to work

[Galaxy]

I've seen preheating fuels for increased efficiency used in the power industry for years now... seems to work

Heating fuel to supercritial levels in consumer products is not going to fly. I can guarentee you that a broken thermostat will lead to an incident which will make the current Toyota debacle look tame in comparision.

[Submariner]

The test car looks like it could achieve good gas mileage regardless of what engine setup it uses.

Put it in, say, an Accord and then test two models back to back.  If there is a 50% increase in fuel economy there, color me impressed. 

[GoCougs]

Superheating does not increase the energy of fuel itself; it'll have x amount of fire/explosive danger regardless.

But yeah, there is a profound amount of headway yet to be made in internal combusion engines; low efficiency and high energy density is fruit that is hanging too low to pass on in favor of socio-political fads, and I think a lot can be done just with the basic engine itself (i.e., without secondary energy recovery/storage systems).

Converting waste heat into mechanical work is the obvious biggie plus as implied in the article current (gasoline) combustion process technology is very sensitive; small variations in fuel quality, timing and combustion chamber temperatures and the engine won't run let having issues with emission, durability and efficiency.

In MY grandscheme I see something along the lines of a diesel (cycle) engine made out of (the engineering definition of) tough ceramics. Diesel cycle is inherently more efficient than the Otto cycle (no throttle plate) and ceramics will both keep a lot of the waste heat in the combustion chamber such that it is converted into mechanical work and be able to handle the increased heat.

[r0tor]

Making use of waste heat is about the only meaningful fruit left.  That could get you from the current 30% efficiency up to somewhere around 40%.  In the end, every variant of the Carnot Cycle (be it Otto, Diesel, Brayton, or Rankine) is still limited by the damn compression (or equivalent) cycle to about 45% or so efficiency.

[Nethead]

GM, and Mercedes have been working for years on self combusting gasoline engines, and they are still years away from production. So I am a bit skeptical that a startup can solve these problems.

Most of the other technologies they talk about are already on the market.

Galaxy:  Agreed.  And solve them without copyright infringements, don't forget.  

Get this system out of the lab and installed on a vehicle that's at the midpoint between tune-ups and at the midpoint of wear on all its parts and then see how it compares to the mileage of an identical vehicle with conventional vehicular combustion hardware.  Some high-efficiency mileage boasts are achievable in carefully-controlled laboratory environments , but have encountered problems in the real world .  

Sometimes, real world situations are exasperatingly difficult to reproduce in laboratories--right, Toyota?

[Morris Minor]

Making use of waste heat is about the only meaningful fruit left.  That could get you from the current 30% efficiency up to somewhere around 40%.  In the end, every variant of the Carnot Cycle (be it Otto, Diesel, Brayton, or Rankine) is still limited by the damn compression (or equivalent) cycle to about 45% or so efficiency.

http://www.tscombustion.com/autoinefficiency.html

[Rupert]

Sounds cool, but I'm always skeptical when OMG someone solves all of the world's problems with one little innovation.

[FoMoJo]

I'm all for innovative technology.  I just don't quite understand what these supercritical fluids are and how they are being applied.

[Morris Minor]

I'm all for innovative technology.  I just don't quite understand what these supercritical fluids are and how they are being applied.

http://en.wikipedia.org/wiki/Supercritical_fluids

[Byteme]

I'm all for innovative technology.  I just don't quite understand what these supercritical fluids are and how they are being applied.

And how much do they cost and what do they add to pollution.

IIRC, there was research going on to use waste heat in the exhaust system to generate electricity (something like a theromcouple, I guess) to free the engine from driving an alternator.  I guess one problem might be that there needs to be a certain amount of heat to activate the catalytic converter so the designers couldn't make that generating system too efficient.

[Morris Minor]

 And how much do they cost and what do they add to pollution.

It's just another incremental step - taking direct injection to the next level. Super-efficient extraction of energy from the various forms of dino juice can only be good news, whether you are using the engine as a diesel-electric generator, direct drive to the wheels or in whatever hybrid configuration in between.