FOR RELEASE: 2007-06-04
On Road Emissions Testing Technology
Chassis dynamometer testing has traditionally been used for measuring tailpipe emissions from automobiles and light trucks. This approach provides a controlled environment and the ability to use large and accurate emissions sampling systems. However, recent developments in emissions measurement technology have given way to the opportunity of measuring tailpipe emissions from a vehicle as it is driven on-road, with the emissions sampling system located on-board the vehicle.
In Challenge X, competing vehicles are driven over a pre-defined drive schedule that is similar in nature to laboratory-based emissions testing. Teams are required to demonstrate simultaneous control of key criteria emissions and will be scored based on an emissions bin-structure.
Multiple Vehicle Technologies Utilized
To reduce regulated emissions, a myriad of combustion and after treatment technologies have been engineered by teams in Challenge X. Both lean NOx traps and urea injection systems have been implemented into diesel powered vehicles to reduce NOx emissions. Using computational fluid dynamic modeling techniques, the University of Wisconsin-Madison and Mississippi State have engineered and optimized urea mixing systems and integrated the into their exhaust stream. The Ohio State University has engineered and integrated lean NOx traps with an upstream reformer to reduce NOx emissions. The reformer eliminates the need for urea, which would be an alternative to urea-SCR systems. These teams, as well as all other diesel powered teams, have utilized small light off catalysts closely coupled to the engine to reduce HC emissions, as well as integrate particulate filters to drastically reduce soot emissions. In addition, various unique thermal coating treatments (such as zirconium ceramic) have been applied to exhaust systems to retain heat and increase after treatment emission reduction efficiency.
To help address vehicle emissions aside from after treatment technologies, Penn State and Texas Tech University have engineered and implemented hydrogen injection systems into their engines. Both teams have integrated port fuel injectors that accurately meter a dilute quantity of hydrogen acting as a second combustible fuel. This technique is used to help displace some of the petroleum fuel used, resulting in a reduction of CO2 tailpipe emissions. Furthermore, these systems assist in the reduction of CO, HC and NOx emissions. Penn State has integrated the system into a bio-diesel diesel powered engine, whereas Texas Tech has integrated the system into an E-85 powered engine.