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Emissions from Heavy-Duty Trucks Converted to Compressed Natural Gas
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Abstract
Natural gas appears to be the alternative fuel of choice for both light-duty and heavy-duty applications. Conversion kits are typically retrofitted to existing gasoline or diesel fueled engines. One problem area is the very limited amount of meaningful exhaust emissions test data on vehicles converted to natural gas, especially for heavy-duty vehicles. In an attempt to characterize the air quality implications of a large-scale natural gas conversion of the City of Houston's fleet of over 9,000 vehicles. a demonstration program was initiated Nine of the City's heavy-duty trucks were converted by the City to operate on compressed natural gas (CNG) fuel. The test fleet included two 1988 model year Ford F700 trucks equipped with 7.0-· gasoline engines, two 1986 model year GMC Model C7D042 trucks equipped with naturally aspirated GMC 8.2-· diesel engines, and two 1983 model year GMC Brigadier trucks equipped with 1990 model year DDC 6V-92 diesel engines that were modified by Stewart & Stevenson for dual-fuel operation. Exhaust emissions were measured from these trucks in a baseline condition and again after conversion to natural gas. The trucks were tested using a heavy-duty chassis dynamometer at 70 percent of their gross vehicle weight rating (GVWR). Emissions of total hydrocarbons (THC), non-methane hydrocarbons (NMHC), carbon monoxide (CO), oxides of nitrogen (NOx), and diesel particulate are reported in grams/mile Fuel economy is reported in energy-equivalent miles/gallon The results from this test program dismiss the widely held conception that simply converting a vehicle to run on natural gas will result in dramatic reductions in exhaust emissions. The general conclusion from these tests was that none of the natural gas conversion systems tested justified wide scale conversion to natural gas based solely on exhaust emissions performance.
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Fritz, S. and Egbuonu, R., "Emissions from Heavy-Duty Trucks Converted to Compressed Natural Gas," SAE Technical Paper 932950, 1993, https://doi.org/10.4271/932950.Also In
References
- Fritz, S.G. “Emissions From Heavy-Duty Trucks Converted to Compressed Natural Gas: Phase I Final Report,” SwRI Report No. 08-3518 July 1991
- Fritz, S.G. Egbuonu R.I. “Emissions From Heavy-Duty Trucks Converted to CNG,” ASME Paper 92-ICE-10, Journal of Engineering for Gas Turbines and Power 114 561 567 July 1992
- Fritz, S.G. “Emissions From Heavy-Duty Trucks Converted to Compressed Natural Gas: Phase II Final Report,” SwRI Report No. 08-3518 March 1993
- France, C.J. et al. “Recommended Practice for Determining Exhaust Emissions from Heavy-Duty Vehicles Under Transient Conditions,” EPA Report EPA-AA-SDSB 79-08 February 1979
- Urban, C.M. “Dynamometer Simulation of Truck and Bus Road Horsepower for Transient Emissions Evaluations,” SAE Paper No. 840349 , SAE Transactions 93 1984
- Code of Federal Regulations Subpart N - Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedure
- California Code of Regulations “California Exhaust Emission Standards and Test Procedures For 1987 and Subsequent Model Heavy-Duty Otto-Cycle Engines and Vehicles,” May 15 1990
- California Code of Regulations “California Exhaust Emission Standards and Test Procedures For 1987 and Subsequent Model Heavy-Duty Diesel Engines and Vehicles,” May 15 1990
- “Methane Measurement Using Gas Chromatography” SAE Recommended Practice, Method J1151 October 1988
- “California Non-Methane Hydrocarbon Test Procedures,” CARB May 15 1990