Saturday, March 22, 2008

Hybrid Strain

I suspect that the majority of people who've plopped down upwards of 30K for a Prius feel that they've somehow discharged a big chunk of the "green debt" owed "The Planet". This is of course a heavy smelly load of you-know-what but the Prius phenom has prospered almost entirely as a result of cachet as opposed to any actual lowering of one's "carbon footprint". Green feelgood for yuppies--feh. Not that it doesn't work, exactly, but its fuel savings in the real world have been, big surprise, rather less than its glowing reputation would lead us to expect.

So it does sort of work but its contribution towards abating "climate change" is not microscopic but downright nanoscopic or even picoscopic. What it has been strangely successful at doing is separating dollars from suckers but who could blame Toyota for milking that teat 'till it dries up? Equally strange though has been the relative inability of other manufacturers to derive similar success in the hybrid trade. I suspect that to subtract the cultural phenom cachet of the Prius from the equation is put one rather off the idea altogether.

The marketing thrust of most of the other big boys in the hybrid game has been to present the vehicles so adorned with hybrid drivetrains as examples of how the consumer might have his cake and eat it as well. The electric portions of the dual drivetrains in many models are there more to provide extra acceleration rather than significant fuel savings. The consumer has not been over impressed with this approach and has in great part stayed away. After all who sees the need to spend 8 grand to bump a Tahoe's mileage from 18 to 22? Even the sainted Honda came a cropper with their hybrid Accord which sported a gasoline engine of near 250 horsepower and smallish unimpressive hybrid accoutrement.

I think the motoring public has a sense, entirely justified, that many of these hybridizing efforts are much more about public relations than any serious fuel or "planet" saving. Let's face it a massive 6000lb. hybrid Tahoe just isn't going to generate much greenie cachet no matter how many PR bucks GM throws at the public. It might be a different story if the hybrid Tahoe got 35 or 40 mpg but since it does little better than half that just what the heck is the point of coughing up close to ten large for the privilege of hauling around another half ton of parts.

Current hybrids are little better than fads and will contribute squat towards anything but manufacturer profits and as GM is discovering precious little of that. Now lest you think I sneer at the whole idea I hasten to point out that the whole hybrid idea is not without merit. The true merit of the idea will not be realized however by the current half measures being employed by automakers. I'm not even sure that the awkward overlaying of electric and internal combustion systems could be fairly described as a "half" measure--more like a quarter or an eighth. From a maker's standpoint this is inevitable for it allows them to use existing platforms that are familiar to the public and to "simply" overlay a battery-powered electric assist system onto the IC system already in place. This cuts developement costs by using as many off the shelf pieces as possible, perhaps an inevitability in cash-strapped Detroit, but this approach simultaneously renders subsequent vehicles as having a considerably less than "new" feeling.

The true realization of the benefits of the hybrid idea has however appeared on the near horizon. Maximizing the efficiencies of this overall idea will mean ceasing to overlay one heavy expensive mechanical system over another and paring things down to essentials. One major technological enabler of this will be what is called a "wheel motor". These devices, in developement for several years now and approaching mass marketability, incorporate an electric motor directly into the structure of the wheel itself. This has several salient advantages. First of all the much larger diameter of the outer rotor confers a mechanical advantage that a conventional motor gains by having to go through a reduction gear train. This characteristic means that a mechanical connection to the rest of the drivetrain is not needed thereby saving significant amounts of weight and complexity.

Wheel motor technology in one shot allows the hybrid concept to reach its full potential. In this true full hybrid configuration wheel motors are powered directly by a moderately sized battery that is charged by a small onboard IC engine attached to a light high-tech generator. The engine would be sized to provide a reasonably short recharge time for the battery system as well as provide a reasonable highway cruising speed for extended trips. In most cases the engine could be less than half as powerful as a conventional vehicle's and still do a fine job. Most modern aerodynamic passenger vehicles require as little as 12-15 horsepower to maintain 70mph on a flat road.

Putting wheel motors on all four corners of a vehicle gets you all-wheel-drive of course but it also gets you traction control and anti-lock braking as well. Speaking of brakes some wheel motor units use built-in brake rotors but others rely entirely on electrical or so named "dynamic" braking which in addition to slowing the car also puts energy back into the battery.

Taking the Honda Civic as a reasonable mid-sized platform for this system an engine of perhaps 40-50 horsepower might well be all that is needed. In addition to charging and steady-state cruising duties an IC engine confers other benefits such as a power source for air-conditioning and hot water for cabin heat and defrost. The battery in this system would be larger than in current parallel hybrids but smaller than any needed by a "pure" electric vehicle. An efficient battery size would be one that would provide say a 20-40 mile electric-only range which would easily handle the majority of commutes. Plug-in charging is a natural adjunct to this system--leave home charged, charge up at work, drive home, plug back in again. For longer commutes the engine would seamlessly kick in to provide whatever charge or power level needed. It would also automatically provide power for cooling and heating without owner intervention. Additionally this setup gets you plenty of reserve zots for those nuclear level sound systems so popular these days not to mention all the other assorted juice-using gadgets that clutter our existences.

This is hardly a something-for-nothing scenario. In steady state highway travel the mileage might not be significantly better than a standard Civic, which is no slouch, but with ever more impressive IC engine tech appearing all the time I'd be surprised if 50mpg or better would not be quite realistic. And no worries about needing to find a charging outlet. Even in steady-state use the system would keep a decent charge level on the battery to assist with passing and hill-climbing duties. Even in the unlikely event that the battery charge drops to near zero levels or fails entirely the engine/generator system would provide a limp mode that would ensure a return to "civilization". Effective city mileage might well be a multiple of that 50mpg depending on specific conditions.

One additional large advantage of this "strong" hybrid configuration is the elimination of several hundred pounds of mechanical gear, transmissions, driveshafts, CV joints, half-shafts, etc. etc. that are no longer needed allowing the use of a larger battery without a large weight penalty. Current hybrids are porky indeed. The Prius pushes well past 3000lbs which is rather beefy for a small "economy" car. The strong hybrid as described here would hardly need to weigh more than a conventional vehicle. The concept should scale up to virtually any size as well.

This is all well and good but it bothers the hell out of me that the "solution" to getting stellar mileage out of a vehicle keeps staring us in the face but we as consumers refuse to see. To wit: Small cars with small engines.

Grrrr. The 'murkin consumer it seems will not go for small when large is available. I've discussed this with friends and we've decided that gasoline will have to go to at least $5 per gallon before there is any sort of big rush toward small fuel efficient vehicles. We're Americans dammit and we likes our big cars, period, end of discussion. I know plenty of folks that would pay 10 bucks a gallon to be able to drive a Tahoe. After all in Europe there are those already paying $8 plus per gal. to drive big thirsty Benzes and Bimmers so why should we be that different. Consequently there is little incentive for manufacturers to offer small light vehicles with modestly powered drivetrains that get superb mileage.

It's true that in the past 30 years that a huge burden of regulation has increased vehicle weights tremendously. That vehicles are wildly safer as a result is unquestionable but along with such things as ever more sound deadening, creature comforts, and a dizzying array of electronics, they've bulked up substantially. In 1975 I owned a Volkswagen Scirroco which although on the small side was hardly in the midget Smart Car league. It weighed 1900lbs. As a consequence its 70 horsepower engine was more than enough oomph for spirited driving. An equivalently sized vehicle today will weigh, at a minimum, 500lbs more. In the case of the Prius, not that much bigger of a vehicle, the difference is well greater than half a ton. No wonder new cars require so much more powerful and thirstier engines. They need them just to get out of their own way.

A light "low content" minimalist sedan similar in size and weight to an original Scirocco with an ultra-tech Toyota or Honda engine sized to the 70 horsepower range might well get 45-50 m.p.g. Good luck selling that here. The car magazines would savage it for its lackluster performance which ironically would be similar to what those same magazines praised to the heavens in the original Scirocco. I fear that the techno whiz-bangery of the hybrid will be required to overcome this absurd resistance to real efficiency. Pity. As for wishing that the auto makers would hurry the heck up and repeal the laws of physics so they can sell us a 50 mpg SUV---well dream on you moron. Whatever the heck you think of climate change alarmism it certainly wouldn't hurt you, or anyone else, to drive a vehicle that gets decent mileage. If nothing else it'll save you money. Lot easier to relate to that than to wring one's hands over the complexities, confusions, and contradictions of being "green".


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