50% Efficiency Boost From New Fuel Injection System

chudnall notes a Technology Review story on a new gas engine injection system that promises increased efficiency of up to 50%. "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."

Comments

Re:Not just "similar" to a diesel

[dylan_-]

Eh, no.

Eh, yes.

That, however, does not make the fuel diesel fuel, as diesel is another refinery product altogether from gasoline.

The fuel is named after the engine, not vice versa (i.e. it's a fuel to work in diesel engines). Diesel engines can use many different fuels.

Not a Diesel

[Fantom42]

People keep saying this is a diesel engine, but it is not. In a diesel engine, the air in the chamber is heated by compresssion up to something hot enough to ignite the fuel. In this design they are heating the fuel and pressurizing it before they inject it into the chamber, so that it turns to vapor as soon as it is injected into the chamber. Someone seemed to be making fun of the term 'supercritical' but that is the word for vapor that has completely transformed from a liquid and has excess internal energy. This is very different from spraying the gas with an atomizer.

Re:I'm sceptical

[realityimpaired]

Y'know, I don't really have a hard time believing that it could get 100mpg at 50mph... 50mph isn't *that* fast, for one, and for two, there's cars on the market today which are able to get 70mpg at those speeds. Even my 3-year old Chev aveo is able to pull about 50mpg at those speeds if I do it right. (arrow-straight, flat road, a/c off, windows closed, manual transmission) And I'm not talking about EPA posted results, I'm talking about real-world testing that I've done in my own car with me driving.

There's even an amatuer sport of sorts that comes from this, called hypermiling. Some of the better hypermilers are able to get over 100mpg out of a car like mine, and the world record is over 200mpg out of a Honda Insight. So no, 100mpg out of a production car isn't that astonishing or out to lunch to me.

Re:I'm sceptical

[Kotten]

I'm sceptical of anything which proposes to simply double the amount of energy extracted...

They claimed 50% increase of efficiency.

...the alternative would be that conventional engines were spewing out half the gas unburned. Which just isn't the case.

The efficiency of combustion engines are ~20% so you could say that more than half is lost (80% actually). An increase with 50% would but it in the 30% range which seems reasonable to me.

Re:I'm sceptical

[Fantom42]

It is right to be skeptical, but the theoretical efficiency of a typical Diesel is in the 50% range.

http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/diesel.html

This thing is not a Diesel engine, but it looks like it might be similar to one.

Efficient or Green? You choose.

[GuyFawkes]

As any (mechanical) engineer knows, to get an efficient internal combustion engine you want compression pressures as high as possible and combustion temperatures as high as possible (an oversimplification, to be sure) because an internal combustion engine is a heat engine, and the greater the temperature and pressure difference between the combustion event in the cylinder, and ambient conditions at the end of the exhaust system, the more efficient it is.

UNFORTUNATELY, some three quarters of the gas that the internal combustion engine draws in from the atmosphere is Nitrogen, and when you expose Nitrogen to the high pressures and temperatures of a combustion chamber, what happens next is simple, and unavoidable, chemistry, you get oxides of nitrogen out the exhaust pipe.

So on the one hand an efficient engine will be running petrol / gasoline at 13:1 compression ratios, or diesel at 25:1 compression ratios, and polluting the crap out of everything.

On the other hand, a "green" engine will be running petrol / gasoline at 9:1 compression ratios, or diesel at 17:1, and wasting energy efficiency like an ice rink in Dubai.

You can't have it both ways.

Re:I'm sceptical

[hey!]

I'm skeptical because I've heard so many reports like this.

However it's not physically improbable to achieve 30% efficiency with an internal combustion engine. Even an ordinary ICE theoretically can achieve 37%. If the combustion temperature is raised, it is conceivable that higher efficiencies could be achieved.

As far as mileage is concerned, that's not related in a straightforward way to engine efficiency under ideal conditions. Toyota's Prius is rated at 51 MPG highway; that's not the electrical system doing that, it's an engine that's tuned to be very efficient at highway speeds and which doesn't have to deliver torque at low speeds.

It's not out of the question to almost obtain twice that in a ultralight prototype vehicle with an engine that marginally outperforms the Prius engine under those conditions, if the rest of the power train was a little simpler and more efficient. The key to the Prius engine is that it can be tuned for higher peak power because it doesn't have to generate much torque at low speeds.