TransForum Vol. 9, No. 1

Hydrogen Engine Evaluation Using MATT

In-vehicle testing of the hydrogen engine on MATT

Through the use of an Argonne-developed test platform, researchers have devised new combustion strategies for hydrogen-powered vehicles that come one step closer to energy-efficient, cost-effective travel that emits no greenhouse gases or other pollutants.

Unlike hydrogen fuel cells, which convert hydrogen to electricity through an electrochemical reaction that yields no on-board pollutants, hydrogen internal combustion engines can produce nitrogen oxides (NOx). Due to the wide flammability range of hydrogen, a hydrogen engine can run at extremely high air-fuel ratios. All else being equal, the leanest combustion allows the engine to run efficiently and reduces emissions. However, the leaner combustion dramatically reduces the power output of the engine.

Using the Modular Automotive Technology Testbed (MATT) (see figure), Henning Lohse-Busch and his colleagues in Argonne’s Transportation Technology Research & Development Center (TTRDC) have determined that varying the air-hydrogen ratio can reduce the trade-off between fuel economy, low-NOx emissions and power for these engines.

“With a constant air-fuel ratio combustion strategy, you have to sacrifice fuel economy, high performance or low emissions,” Lohse-Busch said. “The variable air-fuel ratio combustion strategy that we developed for hydrogen engines resulted in the best fuel economy while achieving very low emissions even without an exhaust after-treatment system.”

MATT is an Erector Set™-like platform for automotive powertrains in which engineers can swap in and out different engines, transmissions and other core powertrain components. It has given Argonne researchers the ability to test a 4-cylinder hydrogen engine on standard drive cycles.

“One of the major advantages of MATT is that it allows us to separately test and benchmark individual components as they work in a system,” said Lohse-Busch.

As they put the hydrogen engine through its paces with MATT, Argonne’s researchers evaluated the fuel economy and emissions generated by different combustion strategies. Lohse-Busch and his colleagues eventually arrived at the optimal variable air-fuel ratio combustion strategy, which allows a hydrogen internal combustion engine to run efficiently and cleanly in a conventional vehicle.

According to Lohse-Busch, these hydrogen-burning combustion engines represent the “bridging technology to the hydrogen economy.”

In the future, TTRDC researchers hope to use MATT to marry the hydrogen-burning internal combustion engine with a hybrid propulsion system. This approach, Lohse-Busch explained, would enable Argonne researchers to reap more benefits from both technologies.

“With the additional power supplied by a battery,” he said, “we can supply the hydrogen engine with leaner fuel streams, enabling the engine to run more efficiently and cleanly.”

Development and construction of MATT were funded by the Department of Energy’s Office of Vehicle Technologies under Lee Slezak.

May 2009