It's Independence Day, so I wanted to focus on something patriotic. And what's more patriotic than a prototype American race car named Patriot? Nothing, that's what. The Patriot was Chrysler's amazing early '90s experiment with flywheels and electric drivetrains. Too bad it would have killed us all.
Well, maybe not all of us, but the core of the project, a 58,000 RPM carbon-composite flywheel, did pose some interesting issues:
"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."
That's from Richard Samul, one of the engineers on the Patriot project. Two dead guys, not safe for drivers or spectators, and the constant fear of explosion? Those are tricky obstacles to overcome. It's a shame, really, because the overall design and concept of the car were really ahead of their time. So let's look at why this potential death-machine was so damn cool.
The project started as a sort of technology showcase concept car, but unlike many concept cars that are doomed to live their lives slowly rotating while pretty women in themed clothing gesture languidly at them, this concept car was going to be an actual racecar.
The initial proposal was to make hybrid LeMans racecar, and not even a simple ICE/Electric motor hybrid as we are already bored with today: the hybrid here was between a natural gas-powered turbine engine and a flywheel-powered electric motor. This was a very ambitious project.
Regenerative braking was specified to limit wear on the brakes and to use less fuel, both of which mean fewer pit stops, which is a big deal since Chrysler wanted to run the Patriot competitively, and their stated goal was to not just win the LeMans Index of Efficiency, but to win outright.
Sadly, the project was doomed from the start, thanks to egos and maddening bureaucratic issues. The turbine engine, for example, was one of the biggest victims of inane paperwork. Here's what the excellent Allpar write-up has to say about the issue:
Ian Sharp had specified an Allied-Signal engine, and had a commitment from Allied Signal to provide five engines, free of charge, with a crew to maintain them. They were state of the art and ideally sized, with the right weight and power. Ian wrote that the corporate people chose another company with little turbine experience, SatCon, because they were part of Ingersol Rand; as Ingersol Rand's air tools were used on the assembly line, they already had a supplier code ("the terrible process of getting a supplier code through Purchasing and Finance made the engineers tear their hair out.") SatCon claimed 30 engineers were working on the project, but Ian wrote that J&P, which had engineers at SatCon, only ever saw two engineers at a time working on the project. They billed Chrysler about $12 million for work never completed [a record from 1993 shows $4.1 million but the project was still ongoing]; but, again, Chrysler could have had 5 free state of the art engines from Allied Signal. SatCon did apparently provide a compact transformer "off the Seawolf program," according to Lee Carducci.
Ian Sharp was the man in charge of the project, and the turbine he selected from Allied-Signal was a very advanced unit designed for a military helicopter. Not only did it fit the specs, but Allied-Signal would have given Chryser five free engines! Chrysler turned down free, ideal engines in favor of the ones from SatCon entirely because it would have been a pain in the ass to get a new supplier code through the paper-pushers. I'm restating all that from the quote because it's so amazingly frustrating.
So, they have a less-than ideal natural gas turbine now but their main traction motor still seems solid, a 500 HP electric Westinghouse motor designed for a Sea Wolf submarine. The key to all of this, though, was the flywheel.
The flywheel was the heart of the project, and there's certainly many great things about flywheel energy storage. But the truth is that in the early 90s, the technology simply wasn't mature enough to safely protect the driver (or anyone or anything around him) from disaster should the 58,000 RPM flywheel fail.
The flywheel was said to hold the kinetic energy of a truck moving at 100 MPH, and tests involving a failure of the flywheel had already proven disastrous. Two engineers were said to have been killed in the flywheel development process, and even running at half-power as it was in later tests, it was still far too dangerous to use.
There were some videos of the car driving, and the car got plenty of excited press at the time. There's even a picture of the car meeting President Clinton. VP Al Gore is in the picture, too, on crutches, in a strange foreshadowing of the car's eventual lame future.
Still, even if the flywheel-based Patriot didn't quite happen, it did manage to have a legacy after all. A number of the F1 KERS systems in use do, in fact, use flywheel energy storage systems, and the Patriot was unquestionably a pioneer in that development.