NOx Emissions and Efficiency of Hydrogen, Natural Gas, and Hydrogen/Natural Gas Blended Fuels

摘要

Engine dynamometer testing of homogeneous charge, spark ignition. lean burn engines fueled by natural gas, hydrogenatural gas blends and neat hydrogen was conducted to determine if NO_x emissions from blended fuel operation can be reduced below those generated from natural gas operation, approaching those due to a 100% hydrogen fueled engine. The preliminary tests were conducted at the University of Central Florida/Florida Solar Energy Center on an eight cylinder automotive engine. The results indicate that the hydrogenatural gas fuel has the potential of meeting highly restrictive NO_x levels. Sandia National Laboratories conducted follow-on. comparative tests using a single cylinder research engine. The Sandia results indicate that the proposed CARB EZEV standard for NO_x can be met without exhaust gas aftertreatment using a 30% hydrogen (by volume) / 70% natural gas blend fuel in a constant speed/power, hybrid vehicle application which achieves 60 MPG gasoline equivalent efficiency.