Evaluation of aftermarket fuel delivery systems for natural gas and LPG vehicles

Abstract

On September 16, 1991 theSolar Energy Institute was designateda nationallaboratory,and its name was changed to the National Renewable Energy Laboratory. NOTICFThis report was prepared as an accountofworksponsoredbyan agencyof the UnitedStatesgovernment, Neitherthe UnitedStatesgovernmentnor anyagencythereof,nor anyof theiremployees, makesany warranty,expressor implied, or assumesany legalliabilityor responsibility forthe accuracy, completeness, or usefulnessof anyinformation, apparatus,product, or processdisclosed, or representsthat itsuse wouldnotinfringeprivatelyowned rights.Reference herein to any srecificcommercialproduct,process,or service by tradename, trademark,manufacturer,or otherwisedoesnot necessarily constituteor implyitsendorsement, recommendation,or favoringbythe UnitedStatesgovernmentor any agencythereof.The viewsand opinionsof authorsexpressedhereindo notnecessarilystate or reflectthoseof the UnitedStatesgovernmentor any agencythereof. Price:Microfiche A01 PrintedCopy A05Codesare usedforpricingali publications. Thecodeis determinedbythenumberofpagesinthe publication. Information pertainingtothe pricingcodes can be found in the currentissue of the followin2publicationswhich are generallyavailablein most libraries:Energy Research Abstracts (ERA); Government Reports AnnouncementsandIndex(G/:_ and I);Scientific and Technica/AbstractReports(STAR);and publication NTIS.PR-360 available from NTIS at the above address. ! PrefaceThis study was designed to evaluate the effectiveness of aftermarket fuel delivery systems for vehicles fueled by compressed natural gas (CNG) and liquefied petroleum gas (LPG). Most of the CNG and LPG vehicles studied were converted to the alternative fuel after purchase. There are wide variations in the quality of the conversion hardware and the installation. This leads to questions about the overall quality of the converted vehicles, in terms of emissions, safety, and performance. "lhere is a considerable body of emissions data for converted light-duty vehicles, and a smaller amount for medium-and heavy-duty vehicles. However, very few of these data involve real world conditions, and there is growing concern about in-use emissions. This report also attempts to assess factors that could allow in-use emissions to vary from the "best-case" results normally reported. The study also addresses issues of fuel supply, fuel composition, performance, saiety, and warranty waivers. The report is based on an extensive literature and product survey and on the author's experience with fuel delivery systems for light-duty vehicles.I would like to thank several people for their contributions to the project. Mr. Bradley Cohen assisted with the literature _arch.A study was undertaken to evaluate the effectiveness of aftermarket fuel delivery systems for compressed natural gas (CNG) and liquefied petroleum gas (LPG). 'Ibis involved a detailed literature and product review to evaluate the performance, emissions, drivability, and safety of vehicles fueled by CNG or LPG.Currently, there are more than 50...