FY2010 - Oak Ridge National Laboratory

Seed Money Fund—
Energy and Transportation Science Division
05885
Rapid Bidirectional Cantilever-Based Anemometer for Engine Intake
and Exhaust Gas Recirculation Flow and Mixing Characterization
James E. Parks, Sam Kim, and Thomas Thundat
Project Description
Cantilever sensors were studied in simulated gas flows to evaluate the approach as a means to measure
exhaust flow in engine applications at high rates of speed. The emphasis is to develop a sensing technique
that will allow characterization of advanced exhaust gas recirculation systems to optimize, via feedback
controls, engine emissions and fuel efficiency performance.
The overarching goal is to provide a technique for measuring the complex gaseous flows in internal
combustion engines so that models of these processes can be validated and engine designs can be
improved. Modern diesel engines are attaining significant improvements in fuel efficiency while
simultaneously greatly reducing criteria pollutant emissions by operating in advanced combustion modes
that are fundamentally different from traditional stratified charge combustion. To achieve the advanced
combustion, high rates of exhaust gas recirculation are require; thus, understanding the air and exhaust
gas handling of engines becomes more critical. Industry has detailed models of the processes, but
techniques to validate the models do not exist. The cantilever sensor would be used as a validation tool if
successful.
Mission Relevance
The project is relative to engine research that directly impacts both energy security and environmental
quality. Research tasks are directly designed to support ongoing efforts in the DOE Office of Vehicle
Technologies. Other federal agencies that may benefit from the research include the National Aeronautics
and Space Administration (NASA) and the Defense Advanced Research Projects Agency (DARPA).
Propulsion research in both of these agencies may benefit from a sensor capable of rapid flow
measurement in hostile environments.
Specific to the internal combustion engine application that the project targets, these engines will continue
to be a primary transportation powertrain for decades to come. To reduce petroleum consumption and
improve national energy security, reductions in petroleum use are necessary, and the improvements in
engine technology by advanced diagnostics techniques can enable the practical implementation of those
reductions.
Results and Accomplishments
A piezoresistive microcantilever manufactured by Cantimer was studied with simulated exhaust gas flow.
The cantilever sensor was inserted into gas flow controlled by a mass flow controller in flow ranges with
linear velocities typical of those experienced in engine manifold systems. The flow was sensed by the
cantilever in both forward and reverse directions relative to the cantilever physical position. The ability to
measure both forward and reverse directional flow is important as pressure pulses in engine manifolds can
create reverse flow conditions from the valve operation of multiple cylinders. The flow of gas induced
bending of the cantilever, which was detected and quantified by changes in the resistance of the cantilever
due to the piezoresistive effect.
Forward and reverse flow was accurately detected by the cantilever. A forward flow rate of 1000 sccm
produced an increase in resistance of 0.4 ohms, and similarly, a reverse flow rate of 1000 sccm produced
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