foolZONE Special Reports for April 1, 2006

Editor's Note: Due to the overwhelming popularity of the earlier parts of this series we are more than happy to endure the hate mail and threatening phone calls from various oil industry executives and Hummer owners to bring you the third installment of Handy's tips for getting 100+ mpg out of your hybrid. But to protect ourselves from potential lawsuits from angry readers, legal counsel strongly suggested that we advise you that these articles are presented here "for entertainment purposes only" and that you should not try these modifications yourself unless you are a trained professional (whatever that means). And if you insist on taking matters into your own hands, we urge you to follow the safety guidelines which management demanded we provide at the end of this story.

In the first two installments, we discussed ways to extend the time your Prius or Civic Hybrid could run from its batteries. These ranged from replacing the spare tire with super-capacitors to such simple mods as ripping out the radio and disconnecting the daytime running lights. Our next set of Hybrid Hacks cover ways to extend range by tapping into publicly-available sources of power, excluding the use of photovoltaics.

Unbeknownst to a large number of motorists, at least based on their behavior, is a structure that has a potentially free source of energy at each intersection. In order to control traffic most intersections have strategically-placed induction coils that are buried in the pavement. These coils normally function as air solenoids, with an applied alternating current that is used to sense the presence of an automobile. A large metal object, such as a car or truck that comes in proximity of these embedded coils, lowers the inductance of the solenoid, increasing the current, which then trips a "vehicle present" flag in the state machine that determines the timing of the left turn arrow, or of the green light itself. Less scrupulous municipalities use even higher-powered pavement-embedded solenoid coils as tripping sensors to time red light cameras. In any case, we will exploit the fact that there is a fair amount of energy to be had when waiting at an intersection for a light to turn green, ideally at an intersection with a red light camera where there's a lot more power to be had and a richer municipality to borrow power from.

A hybrid car is effectively shut down when stopped at a red light, meaning any energy we can put in will go directly into charging the battery pack. By simply wrapping 400 turns of AWG #14 enameled wire and attaching this to the bottom of the vehicle with pieces of coat hanger wire, we effectively convert these intersection solenoids into a step-up transformer. The metal of the vehicle chassis itself is used as the core slug that concentrates the magnetic flux of this transformer assembly, allowing a higher efficiency flux coupling between the pavement's primary coil and the onboard secondary winding. The induced high-frequency alternating current in the secondary winding of our newly-created transformer can then be rectified using high power Schottky diodes in a full-wave bridge configuration, which is then simply tied to the outputs of the diode pack of the onboard alternator of the hybrid. Further coupling efficiency can be had by dropping the coil assembly onto the pavement at each stop by using air cylinders that are connected to a high-pressure reservoir, but such efficiency gains over that of a fixed coil assembly can only be had for average stops that are greater than 35 seconds -- since the compressed air reservoir needs to be replenished.

A prototype thus constructed has shown a four city-block extension of range on a 6 mile in-city commute. Further experiments have shown that illegally parking over a traffic coil for 9 hours will fully charge the hybrid car's batteries for a lower cost than using the onboard gas engine when gasoline prices are more than $3 per gallon and when parking citations amount to $25 or less.

Next month, we discuss the methods in which we can build a stealthy ski rack and use it as an inductive pickup for overhead light-rail power lines to continuously charge a hybrid car's batteries along a light-rail route. We will then conclude our 5 part series by discussing gypsy power: ways to tap into AM radio transmitter power, and into overhead high-tension lines, by using the car body itself as a transformer core.

Must-read safety tips for the amateur automotive engineer:

• Although there have only been a few incidents of car fires that were traced to improper modifications of the wiring or fuel system, it's imperative that you verify that you've used the right gauge wire and re-installed all the grounding straps before powering up the car's primary systems again
• Individuals who attempted to build their own 260,000-rpm super-flywheel energy storage system have had so much bad luck with their projects that we have withdrawn the plans for the carbon-wound inertia element from distribution. Furthermore reports from the few survivors lead us to strongly recommend that if you currently have these plans you should dispose of them immediately and you purchase this component from a reputable OEM vendor or local NASA contractor
• If you are installing the grappling hook that will allow you to attach yourself to passing trucks and use the vehicle's regenerative braking system to top off your batteries on the fly, be sure to add extra temperature sensors to every battery cell. Without this extra thermal monitoring, the first indicator of an overheated cell might be the sudden breeze you'll feel after the rear end of the car is ripped open by a battery that's decided to rapidly vent its contents to the outside world
• Legal counsel has advised us to tell you that the updated ROM code made available for download is only recommended for hobbyists experimenting with their Prius on a closed-course track and not intended for street use. If you do run it on open roads, please note that while the code has been extensively safety-tested, there are a few critical timing loops and decision trees that have been tweaked to the point where the car can display some very un-Toyota-like behavior such as rough idling, sharp acceleration when passing SUVs, and humming "The Age of Aquarius" to itself when sitting at stoplights.

And, speaking of software, please be sure to install and safety-test the "AI Override" switch described at the end of Part II if you decide to compile the optional "heuristic cruise control" code that allows the vehicle to choose its own speed for optimum fuel economy.

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