Fuel cell record-setter

Image credit: SINELAB
Date:31 December 2007 Tags:, ,

Racing has always driven automotive innovation. By building better race cars, carmakers are ultimately able to deliver better production cars. So, in 2005, when students at the Ohio State University Centre for Automotive Research approached Ford about collaborating on a hydrogen fuel cell car capable of setting a land speed record, the company jumped at the opportunity.

Just months earlier, the same group of innovative OSU scholars had set a land speed record (507 km/h) for electric cars. The Ford/Ohio State hydrogen fuel cell collaboration, the 999 Hydrogen Fusion, was unveiled this past July. On August 15 last year, it sped down the long course at the Bonneville Salt Flats in Utah and hit 333,6 km/h – the first world record for a hydrogen-powered fuel cell vehicle. “This wasn’t a PR stunt,” says Ford project leader Matt Zuehlk. “All of the technology used on this vehicle is scalable, so it can be made to fit production cars down the road.” Here’s how it works.

1. Cooling system
There is no traditional liquid-to-air radiator under the bonnet. Instead, a 400-litre ice and- water bath is used to keep the fuel cell cool. The entire nose is filled with ice cubes and water before each run. The cold water is circulated through the fuel cell stack using pumps and liquid-to-liquid heat exchangers. The water goes in cold, comes out hot. The sizzling liquid is then recirculated to the cooling reservoir, where it’s sprayed on to the remaining ice. By the time the water trickles down to the bottom of the reservoir, it’s cold enough to go through the process all over again.

2. Fuel cell
This one-of-a-kind proton exchange membrane fuel cell system has 16 fuel cell rows (Ballard Power Systems Mk902), which together generate at least 400 kW of output. It’s mounted under the vehicle’s passenger cabin to protect it and to keep the centre of gravity as low as possible for highspeed stability. Hydrogen and heliox, a 40:60 mixture of oxygen and helium, are delivered to opposite sides of the fuel cell membranes (there are 1 760 membranes in the car).

Each membrane is in contact with a platinum catalyst that triggers the electrochemical reaction that makes electricity. Electrons are stripped from the hydrogen molecules on the anode side of the cell and fed through an external circuit to power the electric motor. The protons pass through the membrane and recombine with the electrons and oxygen on the cathode side of the cell, creating water vapour.

3. Motor
It takes a lot of power to move a car weighing over 3 000 kg, even on a flat, level surface like Bonneville. So the team chose a massive 200 kg, aluminiumcased, four-pole, three-phase AC motor that produces more than 570 kW and 677 N.m of torque. It was custom-built by McQuin Electrical Power Consulting in Pennsylvania, USA. Motor guru Nigel McQuin, who designed the powerplant for the record-setting OSU Buckeye Bullet electric car, provided the motor for the Ford Hydrogen 999 programme. An inverter, located between the fuel cell and motor, converts the DC current produced by the fuel cell to AC so that it can be used to run the motor.

4. Transaxle Instead of a direct coupling of the electric motor to drive the axle at the rear of the car, the team installed a Tilton carbon/carbon racing clutch. It resides in the bellhousing of a standard Ricardo six-speed manual transaxle borrowed from a 410 kW Ford GT supercar. Using the clutch and only the Second, Third and Fourth gears in the transmission, it’s easier for the driver to get the car going from a dead stop, and it’s easier on the electric motor because of the torque multiplication of the gearbox.

5. Fuel Storage
The three fuel tanks are constructed with aluminium cores wrapped in multiple layers of carbon fibre. A relatively small amount of hydrogen (1,8 kilograms) is stored in one tank, while the other two contain a total of 18 kilograms of heliox. Why a helium/oxygen mixture? Bonneville’s harsh environment makes it impractical to source oxygen from the atmosphere; the air’s high saline content would eventually corrode the fuel cell’s components, adversely affecting its performance. Instead, pressurised oxygen is stored on-board. As a result, there is no need for an air compressor to feed oxygen to the fuel cell. Even more important for a race car, the 40:60 oxygen/helium mixture essentially supercharges the fuel cell because it contains more oxygen than does atmospheric air.

Latest Issue :

Jan-February 2022