A 322,000 kilometer (200,000 mile) Over the Road Test with HySEE Biodiesel in a Heavy Duty Truck 2000-01-2647
In July 1997, the Pacific Northwest and Alaska Regional Bioenergy Program, in cooperation with several industrial and institutional partners initiated a long-haul 322,000 km (200,000 mile) operational demonstration using a biodiesel and diesel fuel blend in a 324 kW (435 HP), Caterpillar 3406E Engine, and a Kenworth Class 8 heavy duty truck. This project was designed to: develop definitive biodiesel performance information, collect emissions data for both regulated and non-regulated compounds including mutagenic activity, and collect heavy-duty operational engine performance and durability information. To assess long-term engine durability and wear; including injector, valve and port deposit formations; the engine was dismantled for inspection and evaluation at the conclusion of the demonstration. The fuel used was a 50% blend of biodiesel produced from used cooking oil (hydrogenated soy ethyl ester) and 50% 2-D petroleum diesel. The demonstration vehicle traveled 326,235 km (202,160 miles) in actual commercial operation averaging 5.27 miles/gallon.
The biodiesel feedstocks used were ethanol and used hydrogenated soy oil produced as a by-product during the manufacture of French fries by the J.R. Simplot Company. The used French fry oil produced a biodiesel referred to as HySEE. Total glycerol of the fuel averaged 0.402% and yield as a mass percent of raw oil averaged 85.4%.
At the conclusion of the operational demonstration, Caterpillar conducted an extensive engine inspection and analysis. Suffice it to say, “Nearly all aspects of this test passed evaluation with flying colors.” The only exceptions were transient emissions - significant increases in PM and related reductions in NOx were observed. The emission changes were attributed to a decrease in injection pressure and a delayed or retarded fuel injection event. These changes were not attributed to the biodiesel fuel. Wear measurement testing results expressed in miles suggest that this engine could be expected to exceed a vehicle mileage of 1.6 million km (1,000,000 operational miles.)
A second identical engine was performance and emissions tested at the Caterpillar Technical Center, Peoria, Illinois. The test engine was conditioned and tested to meet the requirements of Clean Air Act Section 211(b). As part of the testing, personnel from the Department of Environmental Toxicology, University of California, Davis collected samples for chemical analysis and bioassay studies of toxic (non-regulated) emission compounds.
The section 211(b) testing included neat HySEE Biodiesel, neat REE (Rapeseed Ethyl Ester), 50:50 blend of HySEE, and Phillips 21lb reference diesel (2-D). The engine performance and emissions testing results, using a 1997 Caterpillar 3406E engine are shown in the following table.
Samples of both particle-phase and vapor-phase emissions were collected for determination of PAHs, Nitro-PAHs and mutagenicity.
For the particle phase, the HySEE fuel emissions rate for PAHs such as pyrene, benz(a)anthracene, chrysene, the emission rate was considerably lower than the PAH emission rate for diesel fuel. The emission rate for the vapor-phase PAHs from the HySEE fuel was lower than for the 50:50 blend and 100% diesel fuel samples. For example, the emission rates for phenanthrene were about 29.08, 47.4, and 76.3 μg/bhp-hr for the HySEE, 50:50 blend, and diesel fuel hot start cycles, respectively.
Filter and PUF samples were analyzed for 7 different nitro-PAHs. Only 9-nitroanthracene and 1-nitropyrene were detected and could be quantitated. The emission rate using the HySEE fuel was 0.06 and 0.12 μg/bhp-hr for 9-nitroanthracene and 1-nitropyrene, respectively. For the 100% diesel fuel, the emission rate was approximately 5 times higher for 9-nitroanthracene, and approximately 3 times higher for the emission of 1-nitropyrene.
Bioassay analyses were conducted on both the particle and vapor-phase samples. Both particle and vapor-phase extracts were mutagenic. The 100% diesel emission samples were the most potent having specific mutagenic activities (mutagenic activity per mass of particulate matter or per μL of PUF extract) at least 2 times the activity of the HySEE sample. The HySEE mutagenicity emission rates were approximately 6-times lower than the diesel emission rates with metabolic enzymes added and approximately 5 times lower without metabolic enzymes added. The mutagenicity emission rates for the 50:50 blend were higher than the 100% HySEE emission rates, but lower than the 100% diesel emission rates.