At the recent opening of a new hydrogen filling station in Taylor, Michigan, Ford gave attendees the chance to get a brief drive in a hydrogen fuel cell powered Ford Focus. At the same event fuel cell programs chief engineer Greg Frenette agreed to let AutoBlogGreen have a longer evaluation with one of the prototype Focus FCVs. Recently, the call came that the car was ready, and a couple of hours later, a Ford engineer dropped off the car, worth about a million dollars, at my office. After a brief review of the operating procedures for starting and shutting down the car, the Focus was ready for evaluation.
The test car and most of the other Focus FCVs were built-up from pre-2004 Focus sedans. The cars look largely stock from the outside, but there are differences, most notably in the front. The air intake on the FCV is much larger than the stock Focus indicating a need for increased cooling for the electric drive motor and the power electronics.
The story continues after the jump
The original drive-train of the Focus has been completely discarded, replaced with new hydrogen and electric hardware. Under the hood, the Focus gets an 87 hp/170 lbs-ft AC induction motor that also functions as a generator during braking. The motor is connected to a single speed trans-axle. Since electric motors have a flat torque curve from zero up to their maximum rpm, they can get away with out any extra gearing. Sitting on top of the motor is the traction inverter module. This unit is a three phase bridge that has a maximum current capacity of 330 amps and operates at a nominal voltage of 315 volts.
Underneath the car there are more substantial modifications. Where the Focus has a relatively flat floor, in the FCV there is a substantial 6.5 inch step up below the front seats that stretches the width of the car. Under this hump sits the Ballard Mark 902 fuel cell stack. The fuel cell combines the gaseous hydrogen and compressed oxygen to produce electricity and steam.
Continuing back under the car, under the rear seats where the fuel tank normally resides, is the battery pack. The current version of the Focus FCV uses a cluster of NiMH D-cell batteries like the ones you use in a flash light. The battery pack is used to pressurize the fuel cell stack at start up, run the air compressor and also to provide a power boost when needed during normal driving. On the left rear fender is a small grill that serves as the air intake for the fuel cell. The compressor draws in air and pumps it into the fuel cell to provide the oxygen part of the exhaust.
Finally, back in the trunk is the hydrogen tank. The tank holds 4kg (8.8 lbs) of gaseous hydrogen at 5000 psi. The wall of the tank is two inches thick and comprised of aluminum wrapped in layers of kevlar and carbon fiber. The tank is designed to meet all current crash test standards. Ford has thoroughly tested the tank, doing all kinds of impact and crush tests and says they are completely confident of its safety.
The hydrogen tank has a pressure relief valve in the top.
1. The increased cooling demand will be mostly because of the cooling demand of the fuel cell system. Electric drive system and power electronics generate much less heat than those...
Posted at 11:36AM on Oct 30th 2006 by Mirko