Thursday, March 27, 2008

The Fruition of Hybrid Technology

There were more developments last night (which bled into early morning) on the hybrid bike r&d front. It started when I started tinkering with the flywheel and playing around with the idea of installing an electric-ignition on my Honda pressure washer engine which I bought a few years ago, and ended with me stripping three ICEs (internal combustion engines)--the Robin 33c, an 80cc two stroke, and the 150cc Honda.

Basically I was looking for ways of stripping the engines to their bare essentials to reduce weight and size and seeing what might be best suited for the hybrid projects (including the trike, which I've started on again). The biggest thing I noticed is that the flywheel compromises a significant portion of the mass of the engine and eliminating it would result in a significant reduction in weight. I honestly wasn't sure if a flywheel was a necessary component to an ICE but after some research, here's what I've learned:

The majority of small engines (<7hp, which is what I confine myself to on the ICE end due to my limited mechanical knowledge of more sophisticated engines, like the three cylinder 750 on my old Yamaha, for example) are built as a self-contained unit, i.e., all the necessary components to make the engine run are together. This includes the gas tank (usually 1L or less) and the starter, which is typically pull-start (versus electric ignition, as on most motorcycles). When you pull the cord on a pull-start engine, you are essentially using a concentrated burst of force to get the flywheel--a heavy counter-weight connected to the shaft--rolling. The heavier it is, the more momentum it can sustain for continued rotation from that initial pull.

The flywheel contains one, or a series of magnets which pass by another magnetic which generates electricity which creates the spark which ignites the fuel which fires the pistons which turn the flywheel that continues to create the electricity necessary to maintain the combustion which keeps the engine piston's firing.

I realized later that spark plugs need an extremely high voltage that can only be generated by the magneto. I initially thought I could just remove the flywheel and use a battery to due what the magneto does with the flywheel, but the voltage is just too high. But if a 6 or 12v battery (I'm not sure what voltage would correspond to particular sparkplugs) could take the place of the pull-start ignition, the heavy flywheel could be replaced by a composite which would continue to do the flywheel's job of rotating the magnets to create the electricity needed for continuous combustion, at a fraction of the weight. I know composite flywheels are being explored in the field of regenerative energy production...I wondered if I could make one. But I realized in the meantime an electric start could wait and a heavy flywheel wasn't really hurting anything. I could continue to use the pull start.

After taking a drive with my dad in his new Prius, and getting a better idea of how they operate (and explaining it to him), it became clear that the car employs a sophisticated computer system that is constantly monitoring power requirements and making adjustments accordingly. Namely, at the times when peak hp is required, the gas engine and electric motor work together to produce it; when less hp is needed, the car will run on electric alone, and the engine will shut off automatically. Compared with a standard car, the ICE in a hybrid is constantly turning on and off, and that is part of what makes it more fuel efficient and less polluting--simply put: no idling. The engine is there when you need it, and takes a break when you don't.

Although such technology is well beyond my ability to fabricate, I realized that I already have a computer at my disposal to do a rudimentary job of fulfilling the same function (ie, deciding when the ICE should be running versus not). This "human override" option is the basis of the "plug-in hybrid" concept, and it just makes so much sense--to be able to run on pure electric if it is viable, such as on short trips when it is easy to come home afterwards and recharge the battery (hybrids run the gas engine sometimes strictly for the purpose of recharging the battery with the alternator). I think plug-ins should be on the U.S. market, and it is in Europe, but for all intents and purposes commercially available plug-ins are still a few years away. It just baffles me that this is the case, though, since they are already road-ready and tested (that discussion is for another time).

Anyway, the need for a hybrid-electric bike based off the hybrid car model became apparent during my r&d or pure L.E.V.'s (light electric vehicles): battery power alone confines people to shorter trips, since battery cost and technology is not where it needs to be for it to be able to compete with the amazing energy-storing capability of gasoline. People (esp. Americans) don't like the idea of being limited, and the thought of being stranded after you run out of battery juice does not inspire a lot of confidence for consumers who may like the idea, but are not willing to limit their range by using 100% electric vehicles.

But living in the city, the advantages of electric powered bikes are awesome: they are quiet, and non polluting. when you come to a stop there is no idling. when built into the ascetic of a standard bicycle, they do not attract a lot of attention to themselves. Honda caught on to this idea of "disguising" hybrid technology in their hybrid Civics, which are almost indistinguishable from the ICE versions (contrast this with the 1st generation Insight, which had conspicuous rear wheel covers and was a two seater). To me, the idea of riding through Kensington or Center City on a geeked-out E-bike is reason enough for me never to ride one. I don't think I am alone on this; E-bikes are not cool, and they are being marketed to look "different," and I think that's why they aren't selling (Schwinn is catching on, though, with their new retro-electric cruiser fleet with concealed cables, muted colors, standard dual-triangle frames, etc.). The present bike I am building is spray painted black and looks like an old English three-speed...batteries and controller are hidden in leather saddlebags hung from the rear rack, and the motor is concealed in a black metal box. It is so cool looking, and you would never know it was electric.

The 48v 10ah lithium-phosphate pack I recently ordered from a custom-builder in China is an incredible development in battery technology, and with such individuals building packs like this, cost is starting to come down to a point that makes them economically viable. It is a fraction of the weight and size of sealed lead acid packs (the standard for e-bikes) and lasts up to five times longer than SLAs, making them actually cheaper in the long run.

But such a pack will still keep me limited to a range of, say, 20 miles. I'd love to take this bike on longer trips this summer, but won't be able to do it on battery power alone. Here enters the Robin ICE.

"And in this corner, the Robin-Subaru EHO35, weighing in at 5lbs 10.6oz..."

As you can see from the photo, the Robin-Subaru EHO35 is an incredibly compact and efficient design that can offer up to 225 miles per gallon of standard riding (for faired recumbents and trikes, this would be closer to 500 miles per gallon). It's peak hp output of 1.18kw at 7,000 rpms would allow an cyclist to achieve a maximum speed of 40 miles per hour in the drops on a racing bike, or about 34mph on an upright cruiser like my English three-speed cruiser. That is a decent speed, but I would not mind going faster. Adding a 1000w electric motor to complement the ICE would allow top speeds of close to 50mph...that means cruising speeds of over 40mph, which is a great was to get somewhere fast.

But what's great about having both electric and gas at your disposal is it gives you options. For me in the city, the majority of my trips would be run on electric, and I would simply charge the battery when I get home. The combination of low gearing and a three speed transmission (complements of a 3 speed Sturmey Archer hub) makes running on pure electric an ideal option for in-town riding, where its quietness, lack of idling, and high low-end torque offer the best of an electric bike.

When venturing out of the city, the lithium batteries and small motor do not impose a restrictive weight impediment to riding under human power should you run out of juice. But even more exciting is right there, should you choose to use it, is a sub 6 lb ICE that runs through the same transmission, but combines it with three additional overdrive gears for high-speed, continuous running, or simply when you are out of battery juice and too tired to pedal. With the addition of an handlebar mounted electric start and kill switch, the bike has the potential to operate like a true hybrid: coming to a stoplight, you kill the engine; jump off the line when the light turns green using the electric motor (the throttle on the opposite side of the handlebar), thanks to the low gearing; when you reach cruising speed, switch on the ICE and travel, literally, forever, filling up every 100 miles or so with thirty cents worth of gas in your 1 liter tank. If you run out of electric juice on the road, just use the ICE by itself. After all, in addition to the over-drives, it has the same low-end gearing as the electric motor, since it shares its transmission. And there's always the potential to complement with human power.

If you are using a small 6 or 12v battery for the electric start, a small thin-film 12v solar panel mounted on the rear rack would supply the trickle-recharge needed to ensure that there is always enough juice for the electric start which makes this hybrid-performance possible. Small flywheel energy recycling and storage systems (like the CEMB, for one) are being produced as an add-on for vehicles in need of electric recharge. This, in addition to solar power, has the potential to recharge the main batteries while the ICE is running in the same way hybrid automobiles recharge their batteries.

There are so many possibilities, but it seems like things are finally coming together. Once I get a few prototypes produced, I would like to have a kind of mini-tradeshow, (maybe a sidewalk stand on a Saturday in South Philly on a yard sale weekend) to at the very least expose people to alternatives like the ones myself, and others concerned with energy conservation, are developing, advocating, and using as an alternative to the automobile. My friend Michael is also planning a video-documentary bicycle tour across Palestine to promote peace in that region, and I would love to possibly outfit him and his tour partner with one of these small hybrid setups as another way of exposure (and to save them some peddling in the hot desert sun when oasis get few and far between!)

Pics to follow. I felt, for the first time last night, that maybe this idea is not something to be scrapped. Maybe it is my calling. The Vatican has, after all, added environmental degradation to the Sin List...what better way to fight sin than with an electric bike!


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