David Bettencourt, a criminal defense attorney and aviation lawyer in Hawaii, is a follower of Formula 1 racing and energy-efficient systems. He filed a brief with your editor on the following.
Kinetic Energy Recovery Systems (KERS) were a relatively new thing in Formula 1 racing in 2009, had significant development problems and were banned in 2010. Reinstated in 2011, the systems recover the kinetic energy present in the waste heat created by the brakes and exhausts. The energy is then stored in a battery or a light, extremely high-speed flywheel, converted into power and can then deliver a maximum of 60 kilowatts (80 horsepower), which can be called upon by the driver to boost acceleration for up to 6.6 seconds per lap.
Williams is a major Formula 1 constructor and developer. Sam Michael, Williams technical director, explains. “The rules have changed since KERS was last used in F1. Re-fuelling is no longer permitted, so the packaging is different now. We have packaged our KERS system entirely inside the car’s survival cell, below the fuel tank, because we didn’t want to compromise any of the sidepod area for aerodynamics. The car is longer than last year as a result, but the advantages of doing that outweigh the negatives. Assuming you’re on the weight limit, there is no downside to KERS; it’s worth 0.3s and it gives you a better start.”
KERS systems will be used by a great many competitors in the 2012 season and are being developed by a consortium including Ricardo, CTG, JCB, Land Rover, SKF, Torotrak and Williams Hybrid Power.
The potential for commercial and private vehicles is enormous, since buses and cars will not be limited to six-second power bursts. The price, noted below, is a hopeful surprise, and one which, if the systems are successful in providing the projected fuel savings, would enable short pay-back on a modest investment. Imagine one of these light flywheels adding to takeoff power on a light electric airplane, then collecting waste energy in flight to recharge onboard batteries.
According to Ricardo Engineering, “The project aims to demonstrate the potential of using high-speed flywheel technologies – including both (Ricardo’s) Kinergy and competitor systems – in delivering hybrid systems with the potential for 30 percent fuel savings (and equivalent reductions in CO2 emissions) at an on-cost of below £1000 ($1,500), thus enabling the mass-market uptake of hybrid vehicles in price-sensitive vehicle applications.
Ricardo’s Kinergy flywheel is “The subject of nine Ricardo patent families in application… [representing] an advance in mechanical energy storage technology based on a high-speed carbon fibre flywheel operating within a hermetically sealed vacuum chamber at speeds of up to 60,000 [revolutions per minute]. But unlike current devices in which energy is imported and exported via a drive shaft operating at flywheel speed, Kinergy transfers torque directly through its containment wall using a magnetic gearing and coupling system.”
Initially developed for a “Flybus” project, the prototype flywheel could store up to 960 kilaJoules of energy – which translated into a 6.6 second burst, would give a city bus an extra 145 kilowatts (194 horsepower) of energy to win the stoplight Gran Prix. Again, consider the mileage or power benefits for domestic use unshackled by tight racing regulations.
In a further domestic approach that might find other applications, including racing, Mazda has announced a capacitor-based KERS system that stores regenerative energy derived from braking.
Mazda says, “The Intelligent Energy Loop (i-ELOOP) system will begin to appear on production Mazdas in 2012 and is claimed to reduce real-world fuel consumption by as much as 10 percent. Capacitors offer numerous advantages over batteries for short-term energy storage… they can be charged and discharged very rapidly, they store large amounts of energy, they are light and they resist deterioration through prolonged use. The electricity saved will be used to power the climate control system, the audio and other electrical loads.”
According to their press release, “Mazda examined automobile accelerating and decelerating mechanisms, and developed a highly efficient regenerative braking system that rapidlyrecovers a large amount of electricity every time the vehicle decelerates. Unlike hybrids, Mazda’s system also avoids the need for a dedicated electric motor and battery.
“’i-ELOOP’ features a new 12-25V variable voltage alternator, a low-resistance electric double layer capacitor and a DC/DC converter. ‘i-ELOOP’ starts to recover kinetic energy the moment the driver lifts off the accelerator pedal and the vehicle begins to decelerate. The variable voltage alternator generates electricity at up to 25V for maximum efficiency before sending it to the Electric Double Layer Capacitor (EDLC) for storage. The capacitor, which has been specially developed for use in a vehicle, can be fully charged in seconds. The DC/DC converter steps down the electricity from 25V to 12V before it is distributed directly to the vehicle’s electrical components. The system also charges the vehicle battery as necessary.”
These developments indicate an increasing and appropriately accelerating interest and determination to reach high efficiencies and reduce fuel use – always a good thing.