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Nine

How it works

In a controlled auto-ignition (CAI) engine, a lean mixture of air and fuel is compressed to the point of auto-ignition.  Because there is no spark plug, combustion is flameless and there are multiple points of ignition. …

How it works

In a controlled auto-ignition (CAI) engine, a lean mixture of air and fuel is compressed to the point of auto-ignition.  Because there is no spark plug, combustion is flameless and there are multiple points of ignition. The result is “lean low-temperature combustion” which reduces nitric oxide emissions close to zero.   According to David Tonery of Oxy-Gen, this also removes the need for a three-way catalytic converter and delivers the fuel efficiency of a diesel engine.

Compression ignition diesel engines also have limitations and emissions remain a big problem.  Even though combustion is leaner it results in high particulate and nitric oxide emissions.  Both of these emissions can be treated in the exhaust system but this can reduce efficiency by as much as eight per cent – adding about £1,500 to the cost of the vehicle.  

An Homogeneous Charge Compression Ignition (HCCI) diesel engine makes the transition to flameless low-temperature combustion, reducing nitric oxide and particulate emissions close to zero, because the air and fuel is premixed.


 

 

"How it works". Science Scotland (Issue Nine)
Printed from http://www.sciencescotland.org/feature.php?id=71 on 22/08/17 03:48:55 PM

Science Scotland is a science & technology publication brought to you by The Royal Society of Edinburgh (www.rse.org.uk).