Biodiesel produced from soybean oil, canola oil, yellow grease, and beef tallow was tested in two heavy-duty engines. The biodiesels were tested neat and as 20% by volume blends with a 15 ppm sulfur petroleumderived diesel fuel. The test engines were the following: Reduction in PM emissions and increase in NO x emissions were observed for all biodiesels in all engines, confirming observations made in older engines. On average PM was reduced by 25% and NO x increased by 3% for the two engines tested for a variety of B20 blends. These changes are slightly larger in magnitude, but in the same range as observed in older engines. The cetane improver 2-ethyl hexyl nitrate was shown to have no measurable effect on NO x emissions from B20 in these engines, in contrast to observations reported for older engines. The effect of intake air humidity on NO x emissions from the Cummins ISB was quantified. The CFR NO x /humidity correction factor was shown to be valid for an engine equipped with EGR, operating at 1700 m above sea level, and operating on conventional or biodiesel.
The Coordinating Research Council, Inc. (CRC) held its 17th On-Road Vehicle Emissions Workshop in March 2007, where results of the most recent on-road vehicle emissions research were presented. We summarize ongoing work from researchers who are engaged in improving our understanding of the role and contribution of mobile sources to ambient air quality and emission inventories. Participants in the Workshop discussed efforts to improve mobile source emission models, light-and heavy-duty vehicle emissions measurements, on-and offroad emissions measurements, effects of fuels and lubricating oils on emissions, as well as emerging issues and topics for future research.
The Coordinating Research Council held its 16th workshop in March 2006, with 83 presentations describing the most recent mobile source-related emissions research. In this paper, we summarize the presentations from researchers who are engaged in improving our understanding of the contribution of mobile sources to air quality. Participants in the workshop discussed evaluation of inuse emissions control programs, effects of fuels on emissions, emission models and emission inventories, results from gas-and particle-phase emissions studies from sparkignition and diesel-powered vehicles, and efforts to improve our capabilities in performing on-board emissions measurements, as well as topics for future research.
A 2002 Cummins ISM engine was modified to be optimized for operation on gas-to-liquid (GTL) fuel and advanced emission control devices. The engine modifications included increased exhaust gas recirculation (EGR), decreased compression ratio, and reshaped piston and bowl configuration. The emission control devices included a deNO x filter and a diesel particle filter. Over the transient test, the emissions met the 2007 standards.In July 2004, the modified engine was installed into a Class 8 tractor for use by a grocery fleet. Chassis emission testing of the modified vehicle was conducted at the National Renewable Energy Laboratory's (NREL) Renewable Fuels and Lubricants (ReFUEL) facility. Testing included hot and cold replicate Urban Dynamometer Driving Schedule (UDDS) and New York Composite (NYComp) cycles and several steady-state points. The objective of the testing was to demonstrate the vehicle's with the modified engine.Average vehicle NO x emissions from the UDDS cycle were 6.20 g/mi and 4.26 g/mi from cold and hot runs, respectively, with nitrogen dioxide (NO 2 ) emissions ~50% of the total NO x emissions. Over the NYComp cycle, the cold start emissions were 12.75 g/mi and the hot start emissions were 7.74 g/mi. The carbon monoxide (CO), hydrocarbons (HC), and PM emissions were very low, with average PM less than 0.005 g/mile for hot starts over both cycles.The test inertia weight was varied from 46,000 lbs to 63,000 lbs to 80,000 lbs on a random basis for repeated hot-start cycles. The NOx emissions varied from 3 to 5 g/mi over the UDDS cycle and from 6 to 8 g/mi over the NYComp cycle.Steady-state testing was also performed at repeated cruise conditions ranging from 10 to 60 mph. Average NO x emissions on a g/mi basis were the highest for this test matrix at 6.7 g/mi during 10 mph cruise conditions, ~3 g/mi over 20, 30, 40, and 50 mph cruises, and ~1.8 g/mi during 60 mph cruise conditions.The results from this testing showed that the modified engine and emission control systems performed effectively in vehicle operation. The technology performed as expected on two very different test cycles and a range of steady-state speed and load points. The longer-term durability of the technology will be measured after six months with additional chassis testing.
NREL/CP
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