Chassis Dynamometer Emission Measurements from Trucks and Buses using Dual-Fuel Natural Gas Engines
10/25/1999
Emissions from trucks and buses equipped with Caterpillar dual-fuel natural gas (DFNG) engines were measured at two chassis dynamometer facilities: the West Virginia University (WVU) Transportable Emissions Laboratory and the Los Angeles Metropolitan Transportation Authority (LA MTA). Emissions were measured over four different driving cycles. The average emissions from the trucks and buses using DFNG engines operating in dual-fuel mode showed the same trends in all tests - reduced oxides of nitrogen (NOx) and particulate matter (PM) emissions and increased hydrocarbon and carbon monoxide (CO) emissions - when compared to similar diesel trucks and buses. The extent of NOx reduction was dependent on the type of test cycle used.
Authors: Norton, P.;Frailey, M.;Clark, N.;Lyons, D.;Gautam, M.;Addy, J.;Beck, N.
Alternative Fuel Case Study: UPS Delivers with Alternative Fuels
8/1/1999
This four-page fact sheet discusses how the United Parcel Service has integrated alternative fuel vehicles, specifically CNG vehicles, into their fleets. UPS has operated its service with many different kinds of AFVs since the early 1930s. The fact sheet also discusses the different types of alternative fuels and the types of AFVs UPS has incorporated into their fleets.
Authors: Whalen, M.
Barwood CNG Cab Fleet Study: Final Results
5/1/1999
This report describes a fleet study conducted over a 12-month period to evaluate the operation of dedicated compressed natural gas Crown Victoria sedans in the Barwood taxicab fleet.
Authors: Whalen,P.,Kelly,K.,John,M.
Alternative Fuel Case Study: Barwood Cab Fleet Study Summary
5/1/1999
In 1996, Barwood Inc., a taxicab company based in Kensington, Maryland, committed to incorporating a limited number of CNG vehicles into its fleet. This fact sheet summarizes their experience with Ford Crown Victoria sedans, 10 were dedicated CNG models and 10 were standard gasoline models. Fuel economy and cost, maintenance costs, emissions, and total operating costs were compared for each type of vehicle.
Authors: Whalen, M.
Perspectives on AFVs: State and City Government Fleet Manager Survey
2/1/1999
In an effort to reduce national dependence on imported oil and to improve urban air quality, the U.S. Department of Energy (DOE) is promoting the development and deployment of alternative fuels and alternative fuel vehicles (AFVs). To support this activity, DOE has directed the National Renewable Energy Laboratory (NREL) to develop and conduct projects to evaluate the performance and acceptability of light-duty AFVs compared to similar gasoline vehicles. As part of this effort, NREL has undertaken a number of evaluation projects, including conducting telephone surveys with fleet managers and drivers of AFVs in the federal fleet. This report summarizes the results of the survey of state and city government fleet managers.
Alternative Fuel Vehicles: Real-World Perspectives from the Federal Fleet
7/1/1998
Vehicles that run onfuels other than gasoline, or "alternative fuel" vehicles (AFVs), offer great promise for improving air quality and lessening our nation's dependence on imported oil. But if they are to fulfill this promise and replace traditional gasoline vehicles on a large scale, they must meed the needs of the people using them, and consumers must have access to"real-world" information about them. Do they drive as well as gasoline vehicles? Are their refueling stations as convenient as the corner gas station? Can we expect the same reliability that we've come to expect from our gasoline vehicles? How better to answer these questions than to ask the people who are actually running the AFVs? So in 1996, the National Renewable Energy Laboratory (NREL), a U.S. Department of Energy (DOE) national labortory, designed a nationwide study to capture the opinions of federal fleet managers and drivers onthe performance, reliability, driveability, and acceptability of AFVs. NREL put together this short brochure to serve as a "quick look" summaryof the surveys and their results.
Authors: Whalen, P
Emissions from Trucks and Buses Powered by Cummins L-10 Natural Gas Engines
5/4/1998
Both field research and certification data show that the lean burn natural gas powered spark ignition engines offer particulate matter (PM) reduction with respect to equivalent diesel power plants. Concerns over PM inventory make these engines attractive despite the loss of fuel economy associated with throttled operation. Early versions of the Cummins L-10 natural gas engines employed a mixer to establish air/fuel ratio. Emissions measurements by the West Virginia University Transportable Heavy Duty Emissions Testing Laboratories on Cummins L-10 powered transit buses revealed the potential to offer low emissions of PM and oxides of nitrogen, (NOx) but variations in the mixture could cause emissions of NOx, carbon monoxide and hydrocarbons to rise. This was readily corrected through mixer repair or readjustment. Newer versions of the L-10 engines employ a more sophisticated fueling scheme with feedback control from a wide range oxygen sensor. Comparative testing using the 5-mile route was performed in Sacramento, California on Class 8 tractors powered by these L-10 engines, operating on liquefied natural gas (LNG) and similar tractors with M-11 diesel engines. Also, using the CBD cycle, a fleet of Cummins L-10 compressed natural gas (CNG) powered buses in Garden City (Long Island), New York, was compared to a diesel-powered fleet in Cincinnati, Ohio. Data confirms the average low production of NOx and PM, but three higher NOx emitters were found in the Long Island fleet. Energy equivalent fuel consumption for the Sacramento trucks was 29% higher for LNG than diesel, based on carbon content of the vehicle emissions, while for the new buses the CNG fuel consumption was higher by 28%.
Authors: Clark, N.;Lyons, D.;Rapp, B.;Gautam, M.;Wang, W.;Norton, P.;White, C.;Chandler, K.
Using CNG Trucks in National Parks
5/1/1998
The U.S. Department of the Interior (DOI) has successfully introduced cleaner-burning alternative fuel (in particular, compressed natural gas, or CNG) transit vehicles, such as refuse haulers electric trams, to relieve traffic congestion and help to protect the National Park System's (NPS) natural resources and historic sites. As part of this effort, NPS and DOI are working with DOE to implement alternative fuels in heavy trucks to attain goals of environmental sustainability and efficient operation. This report outlines the steps required to put CNG trucks in operation in the NPS fleet.
The Pierce Transit Story Case Study
1/1/1998
In 1986, Pierce Transit made a commitment to the future of the transportation industry and to the environment by deciding to put buses powered by compressed natural gas (CNG) into everyday service. This case study outlines the company's success and how it was achieved.
Alternative Fuels In Trucking, Vol. 6, No. 2
11/1/1997
This issue includes articles on Future Fuels for Heavy-Duty Trucks, LNG Tax Relief, the Status of the Federal Clean Fuel Fleet Program, and the Cummins Engine, which successfully meets EPA and CARB standards.
Running Refuse Haulers on Compressed Natural Gas (Case Study)
11/1/1997
Since 1992, six new refuse haulers have logged more than 60,000 miles--cleaner, quieter miles, with miles with good horsepower and speed as compared to their diesel counterparts. The U.S. Department of Energy sponsors this project. The Alternative Fuels Data Center at DOE's National Renewable Energy Laboratory has been gathering data on these trucks since they went into service.