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Discussion Starter #1
I just read an article about the development of an ICE with 57 % efficiency. Although it is not about evs, I consider this important environmental development.

Article can be found here: http://www.nyteknik.se/nyheter/fordon_motor/motor/article2504727.ece

But is in Swedish, so I will translate:

"They are combining the best of two engine worlds.

Take the best from the petrol engine and combine with the best from the diesel engine. The result is both higher efficiency and lower emissions. Now researching combustion gets 89 M SEK (about 13 M USD).

The money goes to competence center for combustion processes at Lund's Institute of technology (Sweden) and comes from the Energy department and more.

Half of the money goes to low temperature combustion, combining the best of diesel and petrol engines.

"We have reached 57 % efficiency with a diesel running on petrol. With advanced laser diagnostics we are now about to show how it is done" says Bengt Johansson, professor in ICE at the Royal Institute of Technology (Sweden, actually the university I am attending :cool:).

An important part of the the research is in evaluating different fuels. Volvo, Scania, Saab and the oil company Chevron are participating in the project."
 

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Good to read that they are improving the Satan fuel based engines. :D

What would Rudi Diesel think of putting petrol in an engine named after him .
 

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Wow. This sounds very familiar to 'stratified charge', at least I think that is the right term. I heard from a youtube video a few years ago with Bob Lutz saying that the next evolution beyond Direct Injection will be stratified charge, where a gas engine will not use a spark plug ...

I wonder if this is the same thing as the article is saying, because in the article they are talking about a diesel engine running on gasoline..

But Bob Lutz only said it would increase MPG a bit more beyond Direct Injection and would just bring gasoline engines closer to the efficiency of diesel engines.

http://www.youtube.com/watch?v=xXA22Q0qXNM
 

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Interesting. It uses Partially Premixed Combustion (PPC). The fuel is injected late in the compression phase, in a series of pulses to ensure much more effective combustion. The reason they use petrol is that diesel self-ignites too early, before the fuel and air have mixed sufficiently.

Quote from earlier Swedish article here: http://www.nyteknik.se/nyheter/fordon_motor/bilar/article258690.ece
When will the D 60 (new engine) be ready?
"That depends what you mean. We'll have results in a year, and maybe have an engine in five years. Then it will be up to the carmakers to take over."
 

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Um, reality check. Isn't 57% efficiency way beyond the theoretical Carnot efficiency for a heat engine? That efficiency depends on the two temperatures (ignition and exhaust). So achieve that sort of efficiency, you'd need a really high temperature of ignition/combustion. I didn't think that much higher temperature than is commonly used now is possible, unless there is a metallurgic breakthrough. I don't see mention of this, so I'm afraid that this sounds too good to be true (for those that want to keep petrol engines around).
 

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Discussion Starter #7
Um, reality check. Isn't 57% efficiency way beyond the theoretical Carnot efficiency for a heat engine? That efficiency depends on the two temperatures (ignition and exhaust). So achieve that sort of efficiency, you'd need a really high temperature of ignition/combustion. I didn't think that much higher temperature than is commonly used now is possible, unless there is a metallurgic breakthrough. I don't see mention of this, so I'm afraid that this sounds too good to be true (for those that want to keep petrol engines around).
According to wikipedia scientist have found ways to work around that now:

http://en.wikipedia.org/wiki/Heat_engine#Heat_engine_enhancements

And I doubt they would get any money without being able to prove the 57% efficiency! They are researchers, not manufacturers.
 

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Ok, it looks like the Carnot efficiency is around 73%, but for various reasons nothing close to this is achieved. For an Otto cycle engine with r=10 (compression ratio) and specific heat ratio of 1.4, the theoretical efficiency comes to about 60%, so 57% with some sort of breakthrough technique does seem plausible.

Kudos to the researchers.
 
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