Air pollution is a pressing concern that affects our health and quality of life. Traditional ways of measuring ambient air quality have primarily relied on permanent and semi-permanent stationary enclosures.
Continuity and collaboration are two key features of work by the Houston Advanced Research Center (HARC) toward reducing health-threatening emissions from diesel-powered vehicles such as trucks and off-road equipment.
Those qualities are evident in recent efforts by HARC’s Engine and Emission Research Program on two ongoing projects aimed at developing economically efficient measures to achieve cleaner air.
Both projects build on successful work that HARC sponsored and oversaw when it managed the state’s New Technology Research and Development Program (NTRD) and then managed selected NTRD projects from 2006-2011.
NTRD is a legislatively-launched effort to help develop technologies for older diesel-powered engines to help cut their emissions of smog-forming nitrogen oxides (NOx), particulate matter (PM) and other air pollutants that pose major challenges in Texas cities and elsewhere.
HARC's John Colvin with a contractor installing emission test systems on a Silver Eagle truck.The ultimate aim of HARC’s continuing work on diesel emissions – just as it has been the NTRD Program’s goal – is the extensive and rapid verification, certification and then commercialization of such technologies.
Yiqun Huang, Senior Research Scientist with HARC’s Engine and Emissions Control Program, previously headed HARC’s management of NTRD-commissioned projects.
“I think the Engine and Emission Control Program at HARC is successful both in helping the industry to develop new, clean-combustion technologies and the end users, such as fleet owners, to adopt these emission-reduction technologies,” he said.
“And at the same time, we assist government agencies on the demonstration of these new, clean-engine technologies.”
The two current projects that are advancing previous research undertaken by the NTRD program illustrate Huang’s points.
In one project, HARC’s own engine-testing lab, installed last year, has been the site of tests designed to replicate real-world use of engines that power heavy-duty drayage trucks in Texas ports and rail terminals. Such trucks are significant sources of NOx and PM emissions, not just in Texas but around the nation.
This project, supported by NTRD funds sub-granted to HARC by the Texas Commission on Environmental Quality, is based on a previous NTRD-funded project, in which investigators demonstrated the effectiveness under certain conditions of retrofitting such trucks with an advanced exhaust gas recirculation (EGR) system.
The more recent work at HARC recalibrated the engine, showing at least a 50 percent reduction in NOx emissions without any loss in fuel efficiency or the need for a NOx after-treatment system. Further development and testing of emission-control strategies are proceeding.
Drayage trucks are often older models that can be “big polluters,” especially when they wait in long lines to pick up cargo containers at ports, said John Colvin, a research technical specialist at HARC involved with the testing.
Distribution trucks, off-road equipment
The other recent project at HARC has been funded by the U.S. Environmental Protection Agency under its program to promote emerging technologies that show promise. In this project, HARC has been collaborating with two fleet operators – Silver Eagle Distributors, a company headquartered in Houston and the nation’s largest distributor of Anheuser-Busch products, and the Texas Department of Transportation (TxDOT).
In both cases – Silver Eagle’s distribution trucks and off-road equipment that TxDOT uses for building and maintaining roadways – the technologies being tested had undergone previous testing in HARC-managed NTRD projects. They were produced by the Johnson Matthey and Nett Technologies companies respectively.
HARC’s work with the two fleet operators has included program planning, technology reviews, fleet and vendor coordination, procurement of products, emissions monitoring and experience gathering.
The essential goal is equipment that will help keep vehicles in a “legacy fleet,” such as Silver Eagle’s trucks, running while they meet tighter emission standards for newer trucks, Colvin said.
Previous NTRD testing under HARC management helped lead to commercialization of the Johnson Matthey technology (which combines selective catalytic reduction with a particulate filter), and HARC’s recent collaboration with Silver Eagle has been aimed at its wider adoption, he added.