Powertrain & Energy - January 25, 2012 - 13

Velocity contours during the intake process of a spark-ignited engine simulation. CONVERGE automatically generates the mesh at runtime and adds cells at areas of high-velocity curvature using adaptive mesh refinement. (Convergent Science)

“A drop-in replacement spark-ignition engine using methanol, ethanol, gasoline, or CNG could replace standard diesel,” he said.

Boosting, testing, and simulation

To develop such a replacement, SwRI formed the High-Efficiency Dilute Gasoline Engine (hedge) Consortium. HEDGE uses comparatively high amounts of exhaust gas recirculation (EGR) to increase the effective octane rating of the fuel, according to Alger. Key features of HEDGE include high levels of boost, high brake mean effective pressure (BMEP),
SAE Powertrain & Energy

model based control, and advanced ignition systems. Simulation codes coupled with judicious use of test equipment are the vital tools in developing such advanced combustion schemes. “We use a variety of simulation software from other commercial suppliers as well as our own code, Alamo Engine,” said Alger. While the existing codes are good for simulating known combustion physics, they need some improvement to capture the physics of new alternative fuels and mixtures, according to Alger. “We have to run the engines first, get combustion data, and then use that to refine our models,” he said. Once validated, simulation tools allow engineers to look deeper into the process, acting as a virtual sensor. Alger also stresses using multi-cylinder over single-cylinder test engines for advanced combustion research.
January 25, 2012

Powertrain & Energy - January 25, 2012

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