SpeedSource used ANSYS simulation software to speed design of motorsports version of Mazda SKYACTIV-D engine
|Static pressure. In-cylinder pressure contour after injection. Credit: SpeedSource Race Engineering. Click to enlarge.
Earlier this year, Mazda Motorsports announced it would supply racing versions of the new SKYACTIV-D diesel engines (earlier post) to customer teams competing in GRAND-AM’s newly announced GX Class for advanced/clean technologies, beginning with the 2013 season. (Earlier post.) The racing SKYACTIV-D will make its official racing debut in the Rolex 24 Hours of Daytona on 28 January.
The motorsports version of the engine was designed by motorsports research and development company SpeedSource Race Engineering using ANSYS simulation software quickly to design the engine—in about one-third the time of the industry average—without compromising essential reliability standards for the engine’s use in a competitive racing environment. The motorsports SKYACTIV-D clean-diesel engine is the first production-based, four-cylinder racing diesel engine to be used in a major racing series.
|In-cylinder velocity vectors during combustion. Credit: SpeedSource Race Engineering. Click to enlarge.
A streamlined engine design process with ANSYS simulation decreased SpeedSource’s time to market while the high-fidelity simulation results gave the company confidence that its engine would perform as expected in the real world. By spending less time and money on physical testing, SpeedSource was able rapidly to advance to in-house manufacturing and dynamometer testing in its Coral Springs, FL. facility.
We received one of the first production-block test engines straight from Mazda’s production plant a bit later than originally expected, so we knew that we had to make strategic adjustments to the development process to compensate. With ANSYS, we were able to decrease the total solve time by around two-thirds, which was a huge time savings, and were completely confident that we had arrived at the optimal engine design.—Sylvain Tremblay, president of SpeedSource
ANSYS simulation software was instrumental in the design and validation of such SKYACTIV-D engine components and subassemblies as the racing piston geometry and bowl volumes. Specifically, SpeedSource used ANSYS Fluent to model the in-cylinder combustion process for a full engine cycle and the results of this simulation, such as cylinder pressure and temperature.
|V1 intake streamlines. Flow Streamlines of a racing intake manifold iteration, color coded for velocity. Credit: SpeedSource Race Engineering.Click to enlarge.
These results were then used to guide the design on other critical engine components such as connecting rods, pistons, and crankshaft. Fluent was also used to accurately model fuel injection, which is critical to engine performance and efficiency.
The 2.2L SKYACTIV-D engine reduces fuel consumption compared to the current 2.2L MZR-CD diesel by 20% due to a low 14:1 compression ratio and subsequently greater expansion phase after combustion. SKYACTIV-D is also one of the first diesels to comply with Tier II Bin 5 North American emission regulations without requiring expensive selective catalytic reduction (SCR) after-treatments or a lean NOx trap catalytic converter (LNT).