Lean Burn Engine Technology

[Normal_aspirated]

With newer and stricter emission standards coming, contrary to having rich air/fuel mixture maintaining at stoic ratio of 14.7:1...................car manufacturers will be introducing the Lean Burn Engines soon....... check out:

http://www.autozine.org/technical_school/engine/petrol1.htm

 

The direct injection method is making a comeback, e.g the Mitsubishi GDI, Alfa JTS, etc.

  Quote

Green Engine Technology - Petrol Engines

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Lean Burn Engine

Basically, engines which can operate in very lean air / fuel mixture are called "Lean Burn Engines". Japanese car makers, heading by Toyota, are the leaders in this technology.

Apparently, the leaner air / fuel mixture, the more frugal the engine is. But there are two reasons prevent conventional engines from operating in lean air / fuel mixture:

 

If the mixture is too lean, the engine will fail to combust.

Naturally, lower fuel concentration leads to less output.

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Lean burn engines avoid these problems by adopting a highly efficient mixing process. They use special shape pistons, with intake manifolds located and angled matching the pistons, the intake air will generate swirl inside the combustion chamber. Swirl leads to more complete mixing of fuel and air, thus largely reduce the badly-mixed fuel particles, which will not be burnt in conventional engines. This enables more complete burning, not only reduces pollutant, but also allow the fuel / air ratio to be lowered from 1 : 14 to 1 : 25 without altering output.

Today, Lean Burn technology has evolved into Direct Injection, which is basically the former added with direct fuel injection. Toyota, Mitsubishi and Nissan all concentrate in DI engines development.

[Newsunny]

I guess if they settle problems of high temp knocking and NO2 emissions, lean burn can be a reality in the future.

http://home.earthlink.net/~graham1/MyToyot...rs/LeanBurn.htm

http://www.insightcentral.net/KB/faq-non-problems.html

[Zoom3r]

The air swirling thing sounds like Honda's i-DSI to me.

 

NO2 cannot be solved, unless they can make it burn at a lower temperature. At most, we can install filters to filter it out of the exhaust.

[Normal_aspirated]

yup, if it meet the NO2 emission standard.

Honda Insight is still an experimental car.

[Normal_aspirated]

Oh the air swirling thing......i hv attached some pix from the websites below:

 

Because of the vertical tumbler (swirl) effect, the combustion is very efficient so much lesser fuel is needed for the same power output. The current catalytic converter is able to neutralise it, resulting much smaller NO2 emission to meet the coming emission standard,