Chrysler Patriot Hybrid: Perspectives
Richard A. Samul spent his entire 36-year career with Chrysler Engineering around automotive proving grounds. He enjoyed the life of a car fanatic. Some days, it meant test driving cars on the oval track. On other days, he toiled in a road test garage as an experimental dynamometric mechanic.
Of the many projects that Samul worked on during his career, one that remains memorable for him is the Patriot.
In 1993, Chrysler had an idea for a concept car and entrusted British engineer Ian Sharp to execute its design. Sharp created the Patriot to be a Formula One turbine-powered hybrid-electric racing car with flywheel energy storage and regenerative braking. Along the way, though, managers changed many of Sharp’s specifications, in particular replacing the turbine generator unit. See this full history of the Patriot from conception to final production, with the mistakes made along the way.
I worked on the Patriot Project as the dynamometer operator, on loan to Liberty and Technical Affairs, during the early 1990s, for a year or so. The testing was performed at Chrysler Engineering, Highland Park complex, in Building 135, Test Cell 2. It was located in the old Chrysler Turbine Research area.
I worked with Chrysler engineers Mike Royce, Kim Lyons, and Lee Carducci as well as with engineers from SatCon (from Boston, Mass.). The test cell was equipped with a Froud 1200 HP water brake dynamometer that had been used in a prior Chrysler/Lamborghini engine testing program. The electric motor was rated at 750 HP.
The Patriot received much hype and fanfare when it was first introduced. After all, it was to be a great leap forward in racing technology thanks to its use of alternative energy storage and efficiency.
Unfortunately for the Patriot, it seemed for every two steps it leaped forward, it took one step backward.
"There were problems with the Patriot," Samul recalled during a recent telephone interview. He wasted little time pointing out the liabilities of the flywheel.
A flywheel energy storage (FES) system functions by accelerating a flywheel (rotor) to very high speeds and, then, maintaining this energy in the system as rotational energy. As energy is extracted from the FES, the flywheel's rotational speed reduces in an effort to conserve energy.
The ability to use the FES technology as the electrical load leveling device for transient electrical absorption and delivery of power to and from the traction motor was key to the success or failure of the Patriot car.
As it turned out, serious problems with the FES were detected -- the flywheel's mechanical integrity came into question -- and ultimately, it proved too great an obstacle to fix.
“It proved a failure,” Samul said. “There were two deaths as a result of the flywheel. We found out it wasn't safe to put it in a race car. It wasn't safe for drivers or for spectators. There was always a fear it could explode.”
Samul said the Patriot's designers retrofitted the test cell and took it to half-power to make it safer. Despite the engineering changes, Chrysler's engineers could not overcome the serious problems that were associated with the integrity of the flywheel. Among many obstacles, the flywheel was always at risk of shattering -- literally coming apart -- because of high-speed pressure. Also, it was determined that adequate protection from a shattering flywheel would exact too much of a weight penalty to make the necessary change. He wrote:
A flywheel energy storage device that was being tested by another unknown company failed. It was rumored that it killed a couple of engineers. This was the story I was told that ended the project. If true, metallurgy and containment technology needed to be improved, to make for a safe installation in a vehicle.
Testing had reached about 50% of its power level when the project was cancelled by Francois J. Castaing.
Washington Post automotive columnist Warren Brown remembers the problems that Chrysler engineers faced with the Patriot. Asked if the racing car was ahead of its time during a recent online Q & A chat on the newspaper's website, he said: "It wasn't so much that the car was ahead of its tme as it was that ceramic technology was not up to the head and vibration demands of a high-performance car. Ceramic pieces, then thought essential to a high-heat turbine drive train, kept failing. And, ceramic technology was and remains quite expensive."
As much as Samul wanted to see the Patriot project succeed -- and there was much hype and fanfare for it to succeed -- he admitted that the flywheel technology was "a big problem" with the failure of the Patriot. "We weren't ready for it," he said.
Although the Patriot never raced in a Formula One event -- and never attained glory for Chrysler -- Samul isn't bitter. "It was an interesting project to be involved with," Samul said. "But it fizzled out."
Unlike some critics, Samul believes the Patriot was ahead of its time. "Sometimes, the best plans don't always work out."
Afterwards: the flywheel concept survives
Nearly twenty years later, the Formula 1 racing group has requested proposals for kinetic energy recovery systems on F1 cars for 2011, and the likely winner will be a similar flywheel system. If ratified by all the teams, it will become standard. Ian Sharp wrote, “[This is,] in my estimation, the future of onboard energy recovery, not batteries or supercapacitors. The system in question is connected directly to the transmission, is not affected by temperature, is light, and very cost effective.”