Special Coverage

SAE World Congress

DETROIT – BMW AG is a step closer to Zero Emissions Vehicle status with its hydrogen-fueled 7-Series fleet, thanks to just-completed testing by the Argonne National Laboratory.

Argonne’s examination puts the Hydrogen 7 well under Super Ultra Low Emissions Vehicle (SULEV) standards, recording 0.0008 g/mile of oxides of nitrogen emissions, and 0 g/mile of non-methane organic gas emissions.

Argonne also recorded 0.003 g/mile of carbon monoxide, but since hydrogen has no carbon component, the lab concluded that was coming either from the motor oil or the ambient air pulled in through the intake manifold.

Although most of the nearly 100 Hydrogen 7s produced are designed as dual-fuel vehicles capable of running on hydrogen or gasoline, several hydrogen-only models have been manufactured, as well. The dedicated models allow BMW to optimize engine performance for the fuel, and it was a hydrogen-only version Argonne tested.

BMW would like to get the vehicle classified as a ZEV by U.S. regulators, in particular, the California Air Resources Board. But officials on hand here at the SAE World Congress to discuss the testing results say it isn’t clear at this point “how many zeros you have to have after the decimal point” to be considered a ZEV.

California will require 7,500 ZEVs to be sold in the state between 2012 and 2014. So far the state considers only battery-powered electric or fuel-cell vehicles to meet that criteria, so getting the Hydrogen 7 certified as a ZEV could be critical to helping BMW fulfill any requirements it may face.

Don Hillebrand, director of the U.S. Center for Transportation Research, says it was a challenge for Argonne even to measure the Hydrogen 7’s emissions.

“Measuring zero is difficult to do,” he says.

Because Argonne’s equipment had been used for the past five years solely to test gas and diesel vehicles, the lab spent two weeks running the hydrogen vehicles simply to blow the carbon out of the system.

“We didn’t realize (the years of carbon buildup) would be a problem, but it was,” Hillebrand says.

“These are powerful steam cleaners,” he says of the hydrogen 7-Series. “Maybe we should bring them in every couple of years just to clean the equipment out.”

The U.S. Department of Energy dictates what Argonne can work on, and Hillebrand says it decided the lab should test the BMWs because the cars fit with its core mission of examining ways for the country to displace imported petroleum.

“The government realizes there’s a problem” with proliferating hydrogen use because of lack of infrastructure and high cost, he says. “We’re looking at ways to drive hydrogen cost down.”

BMW doesn’t expect the rest of the industry to jump into the hydrogen-fueled IC-engine arena. But it is working to convince other auto makers to adopt standard hydrogen fuel and fueling parameters so any future infrastructure developed will serve both IC and fuel-cell cars and trucks.

“Both vehicles have a place in the future,” says Christoph Huss, BMW vice president-development abroad, type approval and traffic management. “It’s good some manufacturers are working on (fuel-cell) technology and BMW is working on the IC hydrogen engine. Then we can share knowledge.”

The current hydrogen dedicated 7-Series cars have a range of 130 miles (209 km) on their 20-lb. (9-kg) tank mounted in the trunk (it still leaves room for two golf bags, a BMW official notes). The tank holds 18 lbs. (8 kg) of liquid hydrogen and 2 lbs. (1 kg) of hydrogen gas.

The hydrogen/gasoline cars have a range of 425 miles (684 km) in total, including 300 miles (483 km) on gasoline and 125 miles (201 km) on hydrogen.

The next step in development will be to integrate the hydrogen storage tanks with the vehicle, likely running the storage systems down the spine of the chassis along the tunnel.

BMW also wants to get the industry to agree to cryo-compressed hydrogen as the fuel standard, which would work with both the IC engine and for fuel cells. Future BMWs would be capable of running on either the cryo-compressed gas or liquid hydrogen, leaving owners to decide.

The cryo-compressed gas “would be like running regular gasoline instead of premium,” says Tom Baloga, BMW vice president-engineering U.S.

He says BMW should have cryo-compressed hydrogen-tank technology ready in a couple of years.