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This study examined the particulate emissions from a pre-emissions control era vehicle operated on both leaded and unleaded fuels for the purpose of establishing a historical benchmark. A pre-control vehicle was located that had been rebuilt with factory original parts to approximate an as-new vehicle prior to 1968. The vehicle had less than 20,000 miles on the rebuilt engine and exhaust. The vehicle underwent repeated FTP-75 tests to determine its regulated emissions, including particulate mass. Additionally, measurements of the particulate size distribution were made, as well as particulate lead concentration. These tests were conducted first with UTG96 certification fuel, followed by UTG96 doped with tetraethyl lead to approximate 1968 levels. Results of these tests, including transmission electron micrographs of individual particles from both the leaded and unleaded case are presented. The FTP composite PM emissions from this vehicle averaged 40.5 mg/mile using unleaded fuel.

Tins report describes the experimental procedure used to evaluate the effect of selected fuel components (butane, propane and propene) of liquefied petroleum gas (LPG) on both regulated and speciated exhaust emissions. A total of seven LPG fuels were tested on three different vehicles. FTP-75 emission tests were conducted on each fuel blend for all three vehicles. Full hydrocarbon and carbonyl speciation were included for at least one test on each fuel. In general, fuel composition effects on post catalyst emissions were overwhelmed by vehicle to vehicle differences. There was no clear indication that one fuel showed best emissions in all vehicles. Results also suggest some dependence upon initial LPG fuel system calibration. Data presented here may lend itself to further statistical analysis which is beyond the scope of this paper. These mixed results suggest that more research is needed to provide greater insight on the effect of LPG fuel components on vehicle emissions.