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In a continuing effort to include real-world emissions in regulatory testing, the USEPA has included air conditioning operation as part of the Supplemental Federal Test Procedure (SFTP). Known as the SC03, these tests require automobile manufacturers to construct and maintain expensive environmental chambers. However, the regulations make allowances for a simulation test, if one can be shown to demonstrate correlation with the SFTP results. We present the results from an experiment on a 1998 Ford sedan, which simulates the heat load of a full environmental chamber. Moreover, the test procedure is simpler and more cost effective. The process essentially involves heating the condenser of the air conditioning system by using the heat of the engine, rather than heating the entire vehicle. The results indicate that if the head pressure is used as a feedback signal to the radiator fan, the load generated by a full environmental chamber can be duplicated.

A number of spark ignition engines from 1997 to 2003 are analyzed for their overall friction characteristics using the Willans line approach. This methodology appears to be quite robust across many different types of engines. Using a variety of partial and complete engine maps from multiple manufacturers, it is confirmed that engine friction has been decreasing over the decades (compared to past studies). Overall there has been a 25% reduction over 30 years. It is also demonstrated that thermal efficiency (defined here as the slope of fuel mep and bmep excluding enrichment) has been remaining steady during the same period. The application to aggregate engine models is discussed.