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Engine testing in the United States has been updated with the new centralized testing procedure in 40 CFR 1065. This regulation introduces a variety of new checks and tests required for certification testing. Upgrading existing equipment to run these tests in some cases introduces error or does not follow the spirit of the regulation. The term “good engineering practice” is used within the regulation to insure users make decisions on differences or unclear implementation. This paper addresses some of the recommended modifications and evaluates the differences in the results with and without the modifications.

For the past several years, manufacturers have been developing emission measurement systems for Super Ultra Low Emission (SULEV) measurements. The Bag Mini-Diluter (BMD) with an advanced exhaust flow measurement device is designed as an alternative to the traditional method for sampling vehicle exhaust, the constant volume sampler (CVS). Exhaust sampling instruments require system verification tests. The system verification test described and mandated for the CVS in the Code of Federal Regulations (CFR) §86.119-90(c) is a simulated test with propane. The very low concentration measurements required for SULEV regulations demand a more enhanced and accurate verification technique and procedure than the method described in the CFR. This investigation focuses on the technique and necessary equipment for verifying system integrity of the entire emission sampling system, including the Bag Mini-Diluter and the exhaust flow measurement device in the test cell.