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Vehicle and Fuel Emissions Testing

Combining Data into Complete Engine ALPHA Maps

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The National Center for Advanced Technology (NCAT), part of the National Vehicle and Fuel Emissions Laboratory (NVFEL), assesses the effectiveness of advanced low emission and low fuel consumption technologies for a broad range of key light-duty vehicles, engines and transmissions.  In support of this work, the NCAT team developed techniques to combine engine operating test data into a set of complete engine maps suitable for use in complete vehicle simulation models and other technical analyses.  

These complete engine maps estimate an engine’s fuel consumption over its complete operating range spanning idle and motoring, wide-open-throttle and a predefined redline speed.  For each engine analyzed, NCAT uses an in-house modeling tool to combine engine test data from benchmarking tests and/or other sources like technical papers and conference presentations into consistent, publishable, complete engine maps.

Following EPA’s commitment to transparency, NCAT is providing access to the complete engine maps for use in other models, technical analyses, and publications. The files below contain images of complete engine maps, tabular data in a spreadsheet file corresponding to the complete engine map images, a document describing the process for combining the data for the maps, and the Matlab input file NCAT uses in its vehicle simulation model.  Please use the citation included in each document when referencing any of these documents.

Sample BSFC Complete Engine MapSample Complete Engine Map for Fuel Consumption (BSFC)

For more information on NCAT's process for constructing complete engine maps for use in complete vehicle simulation models like ALPHA, see:

For more information on benchmarking and the associated test data packages, see:

Complete Engine "ALPHA Maps" (based on benchmarking data)​

Complete Engine "ALPHA Maps" (based on modeled, published or simulation data)