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- Flywheel hybrid test vehicle nets 22.4% improvement in fuel economy
“Improvements in fuel economy of up to 22.4 percent on the ARTEMIS test cycle (pdf), which represents typical real-world usage, have been demonstrated by a research vehicle fitted with a flywheel hybrid system that includes stop-start technology.
Developed by a consortium of British firms as part of the UK government-backed Flywheel Hybrid System for Premium Vehicles (FHSPV) program, the mechanically-driven flywheel system delivers a claimed 80 horsepower of recovered energy from its self-contained hybrid module.
The consortium says mechanical hybrids solve many of the challenges associated with electrified vehicles. The firms claim the flywheel setup eliminates cost, weight, packaging and recycling issues associated with the batteries in conventional hybrids. Prodrive’s head of vehicle engineering, David Hemming, states:
The research shows the potential of mechanical hybrids as an affordable alternative to battery hybrids. Both the fuel economy results and the driveability are impressive, even with early-stage calibrations and no other design optimization.
The FHSPV vehicle recovers energy via its rear differential and continuously variable transmission and routes that juice into a flywheel. When the driver reapplies the accelerator pedal, the CVT transfers energy back to the wheels. The flywheel and its associated drive system are installed adjacent to the rear axle, in a space normally occupied by the spare tire. The whole system reportedly weighs in at less than 176 pounds.
Designed by Flybrid Systems, the flywheel is constructed from carbon composite and operates in a partial vacuum, allowing it to spin at up to 60,000 rpm. The CVT is built by transmission experts Xtrac and Torotrak. Engineering consultants Prodrive and Ricardo handle the system’s configuration and integration and automakers Jaguar, Land Rover and Ford pitched in to develop the FHSPV.”
For those interested in more detail, go to http://www.economist.com/node/21540386.