Cleaner, More Efficient Engines May Be Just a Puff of Air Away

Clean, efficient engines are the goal of Argonne’s growing Powertrain and Emissions Research Facility. The high-bay-turned-high-tech engine research center now boasts five test areas. All coax data— either alone or in tandem—out of engines that power transportation from compact hybrid cars to diesel train locomotives. State and federal legislation is calling for cleaner emissions from vehicles, and both the economy and the environment need engines to run on less fossil fuel.

The Powertrain and Emissions Facility’s latest addition is the Heavy-Duty Truck Engine Test Cell. Engineers are investigating the effect of injecting air or oxygen-enriched air into diesel engines late in the combustion cycle as a way to improve emissions for these engines before stricter regulations go into effect in 2004. Argonne mechanical engineers developed a control regime that reduces particle emissions (soot) in diesel engines without increasing nitrogen oxide (NOx) formation. NOx is a precursor to ozone and contributes significantly to smog. The technology has patents pending.

“The challenge has always been to divorce the two problems from each other,” said engineer Raj Sekar. “Typically when you reduce NOx, you increase particulates; and when you reduce particulates, you increase NOx.”

Injecting air or oxygen-enriched air into the combustion chamber late in the combustion cycle promotes oxidation of particles as they are forming. But it does not increase NOx, which forms earlier in the combustion process.The test cell features a single cylinder of a six-cylinder Caterpillar heavy-duty truck engine and state-of-the-art gaseous and particulate emissions measurement instruments.

Researchers are validating computer models from the first research stage. “The computational fluid dynamics models show that the angle, timing and pressure of the air or oxygen-enriched air addition is critical to the performance,” said mechanical engineer Doug Longman. “They also show that the concentration of the oxygen in the air is less critical than we thought.”

Argonne engineers will refine the model to better account for the effects of angle, timing, pressure, quantity and composition of air on particulate emissions. Future simulations and research will evaluate changing the location of the injector, and the model will be extended to a small-bore, high-speed, diesel compression-ignition engine equipped with fuel injection. This new generation of diesels uses fuel injection for cleaner emissions.

The research is part of a three-year-long, $1.2 million cooperative research and development agreement among Argonne, Caterpillar and DOE’s Office of Heavy Vehicle Technologies.

Other diesel research at Argonne includes the Compression Ignition, Direct Injection Test facility to analyze cleaner passenger car diesels, and a state-of-the-art Particulate Measurement Lab to determine the size and density of soot particles emitted over time. The techniques used in the lab replace a standard method that relies on filter paper for data. A Vehicle Test Chassis Dynamometer performs emissions tests on all the vehicles in the facility.

For more information please contact Evelyn Brown at 630-252-5510

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