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

29 March 2009

Rube Goldberg Machines on Our Streets

Rube Goldberg was a brilliant cartoonist who satirized Americans’ preoccupation with technology. He was (and still is) famous for drawing outlandish machines that work through complex and humorous chains of causation. His name came to stand for any absurdly complex device.

Today’s auto-industry executives wonder why sales of cars are off 50%. One reason may be what they make and sell.

The internal combustion engine (ICE) that powers cars today is a Rube Goldberg machine come to life. Nearly all of its complexity and expense are devoted to eliminating unintended consequences of its motive force: sequentially exploding fuel.

The ICE derives its power from a series of separately timed explosions of fuel and air. To capture their force, ICEs use reciprocating pistons. These devices must be finely machined and surrounded by special piston rings, so the hot explosive gases won’t escape around them. Because pistons only move up and down, ICEs use crankshafts to transform their reciprocating motion into rotary motion to power the wheels.

Now crankshafts are ridiculous-looking devices, with offset journals to which the piston rods connect and counterweights to keep the thing from vibrating. The forces they handle are considerable, so they must be made of specially hardened alloys and machined to exacting precision. Their bearings are so critical that they require continuous lubrication with circulating oil, which in turn requires a large oil reservoir and a separate oil pump.

And that’s just the beginning. Getting fuel and air into the cylinder and exhaust gases out requires hardened metal valves with precisely controlled motion. Controlling them is the job of another asymmetrical shaft with offset pieces, known as a camshaft, which pushes the metal valves inward against stiff springs. Its rotation relies on special gears and an adjustable timing chain for precision. Timing the actual explosions requires another whole system: spark plugs that make sparks to trigger the explosions and a “distributor” of electrical energy, geared to the main shaft’s rotation, to time the sparks precisely.

Now ignition sparks don’t come for free. They need electricity, a battery to store it, and an electric generator to charge the battery as the car runs and depletes it. In addition, ICEs require external power to “turn” them for starting, so they have special electric starter motors, solenoids that provide massive jolts of electricity for cold starts, and keys and ignition systems to switch on the solenoids and starters.

With all this complexity, the ICE is terribly inefficient. It converts less than 34% of the energy in fuel into motion; the rest it wastes as heat. To keep the wasted heat from destroying the engine, oil and coolant circulate through the cylinder block, moved by special pumps, to draw excess heat away. A water-based coolant, augmented by specially formulated “anti-freeze” compounds in cold climates, flows through a radiator, which vents heat into the atmosphere, where it is wasted and contributes minutely to global warming. The radiator requires a moving fan to boost air flow, which in modern cars has a solid-state-controlled motor and temperature gauge.

But that’s still not all. Even when working perfectly, the ICE is a recalcitrant beast. Its torque (rotary power) depends strongly on how fast the crankshaft is turning. So designers have to add a transmission, with a gearshift and some sort of clutch (manual or automatic), to change gears as the engine “revs up.”

Furthermore, when the car turns, each of two opposing wheels turn at a different speed. So the car needs a “differential” transmission on each axle to allow its wheels to turn at different rates without stressing the axle, wheels and tires. Since the rate at which the engine turns also determines the best fuel-air mixture, the engine needs a fuel injector or (in the old days) a carburetor to change the mixture as the engine “revs up.”

Finally, an ICE requires exhaust manifolds to take the burning exhaust gases out of the cylinders. The manifold leads the exhaust to a single pipe, which has a muffler to keep the still-explosive exhaust from hurting our ears. And if we want to get rid of the worst pollutants before they enter air we breathe, the muffler also must have a catalytic converter, which uses one of the most expensive materials known: platinum.

To sum up, a car’s ICE requires at least a baker’s dozen complete systems to ignite, control and time its sequential explosions, convert their power into rotary motion, and deal with all the undesirable side effects of excess heat and exhaust. Those systems are: (1) distributor, spark plugs and wires, (2) battery and generator, (3) pistons and rings, (4) valves, camshaft, timing gear and chain, (5) piston rods and crankshaft, (6) oil reservoir and oil pump, (7) coolant, coolant pump and radiator, (8) transmission and shifter, (9) differential transmissions for axles, (10) exhaust manifold and pipe, (11) muffler, (12) catalytic converter, and (13) starter motor, solenoid and ignition system to start the whole thing off.

With all these Rube Goldberg systems, it’s a wonder current cars work at all, let alone reliably.

In contrast, an electric car has two systems: (1) a battery and its solid-state controller, (2) one or more electric motors. The same motor(s) that power the car generate electricity as the car slows down and brakes, and a well-designed solid-state controller can put that power right back into the battery. Toyota’s Prius already does all this.

But unlike the Prius, which has a complicated variable transmission, fully electric cars have no need for any transmission at all. The reason: electric motors have a “flat” torque curve. They produce about the same torque throughout their total range of “revs.” That range is far larger than ICEs’ range because electric motors have nothing so asymmetrical and prone to vibration as pistons, connecting rods, a crankshaft or a camshaft. Since heavy-duty commercial electric motors achieve 80% to 90% efficiency, they have no need for coolants or radiators. And since electric motors are small and relatively cheap, designers can put one on each wheel, eliminating axles and axle differentials entirely while providing fully independent four-wheel drive.

Now imagine that you like simplicity and reliability. Which kind of engine would you prefer? Which do you think would be easier to operate and maintain? Which would be less likely to break down and cheaper to repair if it did?

Then imagine that, for most of the last century, designers had to use batteries based on lead—the heaviest non-radioactive, widely available metal—because they had no other technology. Imagine further that they had discovered how to make batteries with lithium, the third lightest chemical element. [Lithium (symbol Li, atomic number 3, atomic weight 7) is about fifteen times lighter per unit of power than lead (symbol Pb, atomic number 82, atomic weight 207).] Imagine that commercial production of electric cars with lithium batteries was imminent. Wouldn’t you want to buy one?

Now imagine that the world’s once-largest car maker (now number two) had promised to make an electric car and sell it in about eighteen months, and that most of the rest of the car industry—although a bit behind—had followed suit. Imagine that the price of fuel for ICEs had yo-yoed between less than $ 1 and $ 4 a gallon in the last four years alone.

Then imagine that you could buy a car that would run on electricity, one that wouldn’t produce any loud noise, smells, stains, carbon monoxide or noxious odors. Imagine that you could do your part to make us energy independent and to reduce global warming by buying one. Imagine further that you could “fill it up” in your garage, without ever going to a gas station. Imagine that [see chart at end] it could reach highway speeds as quickly as another small car and would take you where you need to go for work and routine chores. Wouldn’t you wait for one?

Of course the economy matters. Many people aren’t buying cars because the economy is collapsing all around them and they don’t know whether they’ll have a job or a home next month.

But maybe they’re also tired of spending huge amounts for their second biggest purchases (after their homes) on Rube Goldberg machines. Maybe they’re tired of being jerked around by gas prices that change every week, while the price of electric power stays constant or varies only slowly. Maybe they want to do their parts to curb climate change. Maybe they see the near future and are willing to wait for it.

If so, good luck to all the sellers of Rube Goldberg machines out there. Like sellers of horse-drawn buggies at the turn of the last century, they’ll need it.

P.S. Superfluous Rube Goldberg Machines

While the Obama Administration is considering how much bailout money to give GM and Chrysler, it might read the latest Consumer Reports. In a two-page article [subscription required] entitled “Who Makes the Best Cars?”, CR gives the world’s leading manufacturers report cards. It bases its grades on the average test score of each manufacturer’s tested cars, its extensive customer surveys of reliability, and the percentage of each maker’s tested vehicles that CR recommends.

Out of fifteen manufacturers listed, GM and Chrysler came in dead last, in that order. The percentage of tested vehicles that CR recommends was even more revealing, as shown in the following table:

Consumer Reports’ Percent of Tested Vehicles Recommended
100%95% 89%17%

The overall scores were similiar, with the leading Japanese makers in the mid-to-high seventies and GM and Chrysler weighing in at 57 and 48, respectively. (Ford came in fourth from last, with only motorcycle-maker Suzuki, which started making cars as a sideline, intervening.)

In an auto industry about to be creatively destroyed by new electric technology and environmental necessity, how much sense does it make to invest taxpayer money in cars that are not only Rube Goldberg machines, but the worst Rube Goldberg machines in the field? Electric cars will still need parts like tail lights, bumpers, mirrors and frames, so maybe the bailout effort should focus on parts makers, rather than makers of the very worst cars.


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