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.
Alternative Fuels In Trucking, Vol. 6, No. 3
3/1/1998
This issue includes articles on 1) Ethanol Fuel Demosntration in Hennepin County, Minnesota 2) EPA Revises Tampering Policy for Conversions 3) Evolution of the ATA's Alternative Fuels Task Force 4) John Deere Introduces Two new natural Gas Engines 5) Alternative Fuel Taxes Reduced in Taxpayer Relief Act of 1997 6) EPA Reference Guide to Emissions Standards
A Guide to the Emissions Certification Procedures for Alternative Fuel Aftermarket Conversions
1/30/1998
Emissions certification is still relatively new to the aftermarket vehicle conversion industry. Many in the industry think that as soon as a vehicle is converted to operate on compressed natural gas (CNG) or liquefied petroleum gas (LPG), it automatically runs as clean as or cleaner than it did on the conventional fuel. However, recent studies have shown that aftemarket conversions may not always reduce emissions. To achieve emissions benefits, the conversion equipment must be designed and calibrated specifically for the engine and emissions control system on which it has been installed, and the installation and setup must be performed so as to not adversely affect the vehicle's original emissions performance. The reason for certification, then, is to ensure that these criteria are met, that the vehicle continues to perform properly, and that it continues to satisfy all appropriate emissions standards throughout its useful life.
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.
Perspectives on AFVs: 1996 Federal Fleet Driver Survey
9/15/1997
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 fleet managers.
Addendum to Mobile Source Enforcement Memorandum 1A
9/4/1997
The purpose of this document is to clarify and revise the U.S. Environmental Protection Agency's (EPA's) "tampering" enforcement policy for motor vehicles and motor vehicle engines originally designed to operate on gasoline or diesel fuel and subsequently modified to operate exclusively or in conjunction with compressed natural gas (CNG) or liquefied petroleum gas (LPG or propane).
Alternative Fuels In Trucking, Vol. 6, No. 1
8/1/1997
This issue includes articles on: 1) lessons learned from the biodiesel fuel test; 2) a grocery chain's use of LNG tractors on California roads; 3) using liquefied natural gas as a vehicle fuel; and 4) an LE-55 natural gas engine project which targets 55% efficiency and low emissions.
Perspectives on AFVs: 1996 Federal Fleet Manager Survey
7/1/1997
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 fleet managers.