|Streamlines showing intake process for an SI engine in a FORTE simulation. Source: ANSYS. Click to enlarge.
The US Environmental Protection Agency (EPA) has selected ANSYS simulation solutions to model in-cylinder combustion to develop an advanced test engine that will demonstrate fuel-saving and emissions-reducing technologies. The EPA’s test engine will help establish the feasibility of meeting recently issued fuel standards through improvements to combustion chamber geometries, fuel injection strategies, fuel composition, valve timing and intake conditions.
While physical prototyping and direct tests on real engine hardware can guide engine design, they are very costly and time-intensive. By using ANSYS FORTÉ, the EPA can experiment with engine design in a virtual setting. As a result, its engineers can quickly and inexpensively make multiple design iterations. ANSYS acquired FORTÉ as part of its acquisition of Reaction Design earlier this year. (Earlier post.)
The goal of our Clean Automotive Technology program is to research, evaluate and develop advanced engine and drivetrain technologies that help increase fuel efficiency, reduce regulated criteria emissions such as nitrogen oxides and particulate matter, and cut greenhouse gas emissions. To accomplish this, we needed to understand how changes in engine design and hardware can impact the engine combustion processes.
Using ANSYS solutions to generate realistic 3-D simulations of internal combustion engines, we can gain visibility into critical engine behaviors in a timely, cost-effective manner and obtain accurate and predictive results to guide the development of our test engine.— Matthew Spears, Heavy-Duty On-road and Non-road Center Director of EPA’s Office of Transportation and Air Quality
|Flame propagation for SI engine simulation, cut plane showing automatically generated mesh. Source: ANSYS. Click to enlarge.
The new fuel standards are part of a joint final rule published by the EPA and the Department of Transportation’s National Highway Traffic Safety administration (NHTSA). (Earlier post.) The new standards are designed to further reduce greenhouse gas emissions and improve fuel economy for model years 2017 through 2025 for light-duty vehicles. Combined with the previous EPA and NHTSA standards, the new program is projected to result in model year 2025 vehicles emitting one-half of the green gas emissions from the 2010 model year.
Designing high performance internal combustion engines that meet regulatory mandates for reduced emissions is perhaps the top challenge faced by today’s automotive manufacturers. We are excited to support the EPA as the agency uses our computer simulation solutions to create its test engine. Reaction Design’s fast, accurate and cost-effective modeling is critical to developing products that translate reliably to real-world functionality and lead to new advancements in engine and fuel technology.—Bernie Rosenthal, general manager at ANSYS
In addition to gaining a better understanding of combustion dynamics through CFD modeling, the EPA intends to use ANSYS’ detailed soot modeling capabilities to more accurately predict soot mass and particle size distribution, important metrics in the standards.
|Simulation (top) and experimental measurement (bottom) showing regions of soot formation in the engine cylinder during combustion. Measurement is reproduced from: A. P. D. Cruz, J.-P. Dumas, and G. Bruneaux, SAE Technical Paper Series, 2011-01-1390, 2011. Click to enlarge.