Performance and Emissions of Diesel and Alternative Diesel Fuelsin a Modern Heavy-Duty Vehicle

摘要

Conventional diesel fuel has been on the market for decades and used successfully to run diesel engines of all sizes in many applications. In order to reduce emissions and to foster energy source diversity, new fuels such as alternative and renewable, as well as new formulations, have entered the market. These include biodiesel, gas-to-liquid, and alternative formulations by states such as California. Performance variations in fuel economy, emissions, and compatibility for these fuels have been evaluated and debated. In some cases, contradictory views have surfaced. 'Renewable' and 'clean' designations have been interchanged. Adding to the confusion, results from one fuel in one type of engine, such as an older heavy-duty engine, is at times compared to that of another type, such as a modern light-duty engine. Two fuel suppliers, an engine manufacturer, and a large transit district have worked in partnership to conduct a large-scale fleet and emissions test to evaluate the performance of several diesel fuels in a controlled and statistically designed research program. California Air Resources Board (CARB) diesel fuel, a 20% biodiesel blend (B20), and gas-to-liquid (GTL) fuel were tested for 18,000 miles in several modern urban buses. Additional fuels were tested in a controlled environment in a heavy-duty chassis dynamometer facility, using the same engine type, to determine the emissions level and fuel economy. This document provides a detailed description of the program along with statistical analysis of test results for eight diesel and alternative diesel fuels that cover a range of products used in the North American market.