Washington, December 7 (ANI): Researchers at the Technische Universitaet Muenchen (TUM) in Munich, Germany, have demonstrated a diesel truck engine with barely measurable emissions.
The research team, headed by Professor Georg Wachtmeister from the Chair of Internal Combustion Engines, has succeeded in reducing the pollutants in exhaust emissions to barely measurable levels.
The engine is the centerpiece of the research project NEMo (Niedrigst-Emissions-LKW-Dieselmotor), the German acronym for "lowest emission truck diesel engine."
The researchers want to design and fine-tune their engine so that it complies with the Euro 6 caps - without resorting to a catalytic converter.
The engine is already close to meeting the more stringent Euro 6 emissions standard.
The TUM researchers designed the LVK test engine in such a way that the air-exhaust mixture is injected into the combustion chamber under high pressure.
The engine's turbo-charger compresses the mixture to ten times atmospheric pressure - more than double the pressure mass-production vehicle engines can handle.
Compressed in this way, the air-exhaust mixture contains enough oxygen for the diesel fuel to burn completely.
They coupled this innovation with another improvement, at the nozzle that injects diesel fuel into the combustion chamber.
It atomizes the fuel into microscopic droplets, allowing them to burn completely.
In larger droplets produced by conventional injectors, only the outer layer of fuel molecules are burned, like an onion whose first layer has been peeled.
The resulting exhaust fumes envelop the fuel droplets, shielding them from the oxygen.
The shell of exhaust gases gets increasingly dense with each "onion layer" that goes up in flames. Eventually, it becomes practically impossible for oxygen to react with the fuel.
The result is soot formation.
The NEMo injector nozzle atomizes diesel fuel at a pressure of over 3000 bar to generate a fuel mist that burns very quickly and practically soot-free.
Unfortunately, this also results in surging temperatures; a tricky situation, and finding the right balance between the three parameters of exhaust gas recirculation, boost pressure, and nozzle configuration proved challenging indeed.
Yet, the engineers at the Chair of Internal Combustion Engines at the TUM are not content with fulfilling the Euro 6 Norm.
They want to find out precisely how soot is formed in the split seconds during which the fuel droplets burn up.
For this, the researchers constructed a tiny pipe that is shot into the center of the combustion chamber at lightning speed.
Using this method, 13 samples can be taken during a single ignition - an ideal situation for studying the growth of soot particles and developing engines with even lower emissions. (ANI)
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