Diatribes of Jay

This is a blog of essays on public policy. It shuns ideology and applies facts, logic and math to economic, social and political problems. It has a subject-matter index, a list of recent posts, and permalinks at the ends of posts. Comments are moderated and may take time to appear. Note: Profile updated 4/7/12

21 May 2015

Electric Geezermobiles

[For both readers and me, it’s hard to be ruthlessly analytical and deadly serious all the time. The post below provides a bit of relief, in the form of not-so-improbable engineering whimsy. For more serious recent fare, click these links for: coping with our brave new corporate world, and what to expect of bonds and interest rates.]

Some things are counterintuitive but not too complex. Einstein’s special theory of relativity is one. It’s equations involve only simple algebra; they don’t even use calculus. Yet the theory predicts important and counterintuitive results of velocities near the speed of light—dilating time, contracting length, increasing mass, and mass-energy conversion (E = mc2)—that are now standards of both science and science fiction.

So it may be with electric cars. I’ve already penned an essay discussing how their makers have mostly missed the boat, trying to build electric cars that look and act just like gasoline buggies.

But what if they’ve also missed their best market? What if it’s not youth, who have enough trouble today just paying off college loans and getting decent jobs? What if it’s not the rich early-adopters who buy Teslas, when there are so many other competing luxury brands? What if it’s not even the harried homemaker, who needs only a short range to do the shopping, take the kids to school and make it to a close-by part-time job?

What if the best market for electric cars is geezers like me?

At first glance, that may seem counterintuitive. Geezers adopt something entirely new? Don’t we all revel in nostalgia? Don’t we lust in our hearts for the dirty, noisy, polluting power of big cylinders filled with massive, precision machined pistons and exploding mixtures of gasoline and air? Don’t the men especially recall the joy of crawling under a dirty chassis, lifting heavy, greasy parts, pushing the old torque wrench, and hearing the primal roar when it all comes back together again?

Maybe not. We geezers also like clean, quiet, light and simple things. More than other drivers, we would like to be able to plug our cars into our garages when we finish our rounds, rather than drive to unsafe gas stations, let alone in rain, ice, wind or snow.

More to the point, retired geezers by and large have the cash and the leisure to experiment. As a rule, we don’t drive long distances. And we would like machines that don’t pollute our garages with dripping oil, brake and transmission fluid, not to mention gasoline fumes and carbon monoxide.

What do we geezers value most? Health care. As we age, we return or move to crowded cities, or to equally crowded substantial suburbs, seeking good doctors and hospitals nearby. Most of us aren’t going to be driving more than 50 miles a day, at least not often. So we don’t need over 100 miles in range.

Most of us don’t even drive every day. So we can buy a solar array and drive on the sun, charging and driving on alternate days. Youngsters and young families, who have to go to school or work every day, can’t do that. So maybe we geezers, who have the age, retirement leisure and (in our retirement funds) liquid cash to experiment, are the best market for electric cars today.

If so, what kind of electric Geezermobile would please us most?

First of all, it would be light. At least everything but the battery pack, which stores the motive energy, would be light.

Why? Recall Newton’s Second Law, F = ma. The force required to accelerate a mass is equal to the mass times its acceleration.

In electric cars, the propulsive force and the range are proportional to the mass of the battery, which stores the energy and supplies the force. But according to Newton the resulting acceleration is inversely proportional to the mass of the entire car, thus:

F = X (mbatt) = (mbatt + mrest) a, or

a = X / (1 + mrest/mbatt).

Here X is an engineering constant relating the electric motors’ accelerative force to the battery’s mass. For present purposes we need not know it precisely.

This equation is fundamental to electric-car design. It shows that you maximize the car’s acceleration and performance, plus its range, by minimizing the ratio of the car’s non-battery mass to its battery mass. That’s not counterintuitive, but Newton confirms it with math.

Teslas get superb performance by minimizing that ratio with massive batteries. As a result, the Model S is a heavyweight, tipping the scales at 5,000 pounds. But there’s also another way: you can maximize performance and range by minimizing the mass and weight of everything else in an electric car besides the battery.

So how would I design my Geezermobile? It’s chassis would be made of light, strong aircraft-grade aluminum. Its body would be light, strong carbon fiber, as in Boeing’s Dreamliner. To improve the safety of a light vehicle, the aluminum chassis would have crush points or crash-only shock absorbers that collapse but keep the cab and battery intact in an accident. (A friend’s old 1978 Caddy has such an arrangement—two big shock-absorber-like supports for the massive rear bumper.)

For stability in rain, ice and snow, every wheel would have its own electric motor. So each motor would have roughly one-quarter the size and power of the single ones, or one-half the size and power of the dual ones, that most electric cars now use. These smaller motors could easily hide in their own wheel wells, leaving plenty of crushable chassis space for both front and rear trunks. (As is customary now, the battery pack would be large and flat and lie in or below the chassis, in order to distribute its weight evenly, lower the car’s center of gravity, and improve cornering.)

High-power solid-state electronics would not only control power and speed and provide regenerative braking, as they do today, even in hybrids. They would also provide instantaneous, all-wheel traction control for the resulting, fully independent four-wheel drive. Insofar as we Geezers are concerned, two-wheel drive would become as extinct as the Dodo, along with mechanical trans-axles and differentials. Spinouts and 360s in rain, ice or snow would be much less frequent.

The front trunk would contain the seldom-used spare tire, jacks and other tools, plus room for luggage. The rear trunk, being more accessible in parking lots, would be the workhorse. It would have a solid, rollout basket, for ease of loading heavy groceries and other shopping loot without stooping, which pains us geezers.

Instead of a gas-tank outlet, the Geezermobile would have a fifty-foot long power cord coiled on a spring-loaded retracting spool like those in vaccuum cleaners. If a geezer were ever so risqué as to have a tryst in a motel, he or she could park right in front of the room, spool the power cord through the window, and recharge the car during an afternoon delight. You don’t have to be an adman to think of the delicious possibilities for advertising that.

The power plug would be a standard three-prong (grounded) plug that fits in any three-prong outlet. A separate, exterior compartment near its portal would contain physical adapters for 240 volt, three-phase or any other power exotica. There would be no fiddling with switches or adjustments: solid-state electronics would sense the voltage, phase and other power parameters and do all the thinking, just as they do now in virtually every charger for laptops, tablets and mobile devices.

The interior electronics would be entirely user-friendly. Audio and cell-phone controls, along with cruise control, would be mounted on the steering wheel within easy reach. Automatic Bluetooth would integrate the driver’s cell phone, tablet and mobile music with the car’s audio system. “Trainable” oral commands would control everything.

Rear-facing backup cameras would ease stiff necks. And cup holders would be in every conceivable, reachable place. There would even be a small blanket compartment, on the back of the front passenger seat for easy access by the driver. It would hold a blanket, and maybe a small, plush head pillow for off-road naps. (Remember our Bill of Rights’ unwritten guarantee: every geezer has the inalienable right to a nap daily. Why not take it in your quiet electric car, to music from your own iPod?)

Finally, the electric Geezermobile should have high or user-adjustable ground clearance. Those of us who still live in the country, like me, need that.

Could my Geezermobile reproduce the Tesla’s head-snapping acceleration? I don’t know. You’d have to know the precise value of X for that. Maybe not.

But we geezers probably shouldn’t drive cars that accelerate too much faster than others on the road. We might hit something or provoke road rage. We geezers don’t want to do that, do we? Better to stay invisible, except when among friends and loved ones.

We geezers should be happy with reasonable speed and pep, not to mention a clean, quiet, simple, exhaust-free car that we can “fill up” in our garages and that will free us from going to gas stations ever again. Whenever we can, we should drive on the sun and keep fossil fuels in the ground, where God made them. I, for one, would be quite happy doing that.

Footnote. Einstein’s other theory of relativity—the general one—is the toughie. It requires tensor calculus. The ability to “visualize” multidimensional spaces doesn’t hurt. That theory, not the special one, is the one that only a dozen or so people worldwide probably understand well. But the special theory should be taught in every high-school physics course, if it’s not already. It’s as basic to physics as evolution is to biology.



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