[Paleopsych] Mechanical Engineering Magazine: The End of the M.E.?

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Mon Jun 6 18:00:38 UTC 2005

The End of the M.E.?

    They call this "convergence." Old lines are changing, or disappearing
    altogether. What it's doing under the hood is downright electrifying.
    by Peter W. Huber and Mark P. Mills

    The turf still divides up quite neatly. The electrical engineers move
    the light stuff--electrons, power, bits, and logic. The mechanical
    engineers do the heavy lifting; they move atoms. And, like it or not,
    the MEs still control most of the real estate.
    Look at our cars. They're made of big heavy things that shake, bounce,
    and sway; they're propelled by pistons, shafts, gears, and belts;
    controlled by shafts, gears, valves, and hydraulic fluids. All the
    really important parts go click-click, bang-bang. The car is a 100 kW
    (peak) machine. The stuff that hums instead of clanking, the electric
    load, peaks at 2 kW.
    Mechanical engineers control most of the rest of our energy economy,
    too. The United States consumes 100 quadrillion Btus, or quads, of raw
    thermal energy every year, in three broad sectors--electric power,
    transportation, and heat--with consumption split (roughly) 40-30-30
    among the three. But electric power plants themselves are mainly
    thermomechanical: The furnaces, boilers, and turbines themselves
    consume over half of the fuel; only about 16 quads worth of mechanical
    energy actually get to the shafts that spin the generators that
    dispatch the gigawatt-hours.

    Komatsu's 930E is a 2,000 kW truck. A 16-cylinder diesel engine drives
    a generator that powers electric motors on the wheels.

    It doesn't have to be that way, and pretty soon it won't be. General
    Electric's 4,400-horsepower, diesel-electric GEVO-12 locomotive is
    powered by an enormous, diesel-fueled engine-driven generator;
    everything beyond is electric. Komatsu's 930E--a monster mining truck
    with 320-ton capacity--is propelled by a 2-megawatt Detroit
    diesel-electric generator. Everything else, right down to the 12-foot
    wheels, is driven electrically. Submarines have been largely
    all-electric for decades, and the surface ships now on the Navy's
    drawing boards are all-electric, from the propeller to the guns.
    Thermomechanical engines are still the prime movers on all of these
    platforms, but what they move is electricity. An on-board generator
    powers an all-electric drivetrain; an electric motor drives the
    propeller or wheels.
    Electric drives are taking over because an electrical bus can convey
    far more power in much smaller, lighter conduits, and do it far more
    precisely and reliably, than even the best designed mechanical
    drivetrain. Indeed, on the key metrics of speed and power density, the
    electrical powertrain is about five orders of magnitude better.
    Electricity moves at close to the speed of light; all thermal and
    mechanical systems move at the speed of sound, or slower. It takes
    10,000 driveshafts in 10,000 redlining Pontiacs to convey about as
    much power (1 gigawatt) as a single power plant dispatches down a few
    dozen high-voltage cables. By a very wide margin, electricity is
    indeed the fastest and densest form of power that has been tamed for
    ubiquitous use.
    But precisely because it is so fast and dense, electricity is
    inherently difficult to control. Direct-drive electrical systems are
    fast all right, but they tend to jitter, overshoot, jerk out of
    control, and fall off the edge. The solution, historically, has been
    to get mechanical again--wrap the electric coils and magnets around
    heavy, inertial, and frictional components to get back to a simple and
    steady source of mechanical power--rotating a shaft, say--which can
    then be channeled through gears, belts, hydraulic fluids, and other
    arrays of click-click, bang-bang logic well before it reaches the
    final payload. Until recently, direct-drive electrical movers--systems
    in which the power stays electric right down to the very threshold of
    payload--have remained the exception, not the rule.

                               Power in Control

    But big motors and their electric power supplies can now be built
    compact and precise enough to mimic the small muscles of a hand. A key
    breakthrough occurred in 1982, when Hans Becke and Carl Wheatley (both
    at RCA) were granted a patent for what is now called the insulated
    gate bipolar transistor. IGBTs are high-power semiconductor gates.
    They control kilowatts almost as efficiently as logic semiconductors
    control the picowatts that we call bits.
    Sensors have also become sufficiently small, fast, and accurate to
    provide real-time feedback of what's happening at the payload. And
    cheap microprocessors are now readily available to make sense of it
    all, and to constantly recalculate how much power to dispatch to the
    drive to make it do exactly what's needed.
    Supplied with a suitably shaped and amplified stream of power, a
    loudspeaker vibrates a diaphragm through a Beethoven symphony; do the
    same with a hundred kilowatts, and you can run a Pontiac. What's new
    now is that inexpensive semiconductors are available to provide the
    extraordinarily precise control of very large amounts of electric
    power, at very low cost, in very compact controllers.

    The sidestick, being tested by Mercedes-Benz, is part of a fully
    computer-controlled car handling system of the possibly near future.

    Because they move less material in the middle, direct-drive
    powertrains have far less inertia and friction; and because they are
    informed by very fast sensors controlled by computers they can react
    much faster to the outside world. Direct-drive motors can thus reach
    levels of precision that are completely unattainable with any
    conventional technology. With less weight in the powertrain, and fewer
    moving parts, direct-drives are also more robust. Pneumatic and
    hydraulic fluids leak, turn into molasses when they get cold, and are
    easily contaminated. Shafts, belts, and pulleys need lubricants, and
    get bent out of shape when they expand or contract. They corrode and
    need periodic maintenance. Electric wires don't.
    The transformation is already well under way in the car's peripheral
    systems. The belts and pulleys that drive water and oil pumps, and
    radiator cooling fans, are giving way to electric motors. The best
    brakes are already electrohydraulic; all-electric brakes will follow.
    With electronic throttles, the gas pedal sends electrical instructions
    to a microprocessor that controls the fuel injection system
    electronically. Drive-by-wire electric power steering began appearing
    in production vehicles in 2001. Passive, reactive, energy-dissipating
    springs and shock absorbers are being displaced by an active array of
    powerful linear motors that move wheels vertically as needed to
    maintain traction beneath and a smooth ride above.
    And electric actuators will displace the steel camshaft on every
    valved engine. Put each valve under precise, direct, digital-electric
    control, actuated independently by its own compact electric
    motor--open and close each valve as dictated by current engine
    temperature, terrain, load, and countless other variables--and, in
    effect, you continuously retune the engine for peak performance.
    Belts, shafts, and chains melt away. Everything shrinks, everything
    gets lighter, and every aspect of performance improves--dramatically.
    To meet this steadily rising demand for electric power, car
    manufacturers are making the transition to a 42-volt grid to replace
    the existing 14-volt grid. Lower-voltage wires just can't convey large
    amounts of power efficiently. A new 42-volt industry standard emerged
    recently, and half of global automobile production will be on a
    42-volt platform within the next decade or so.
    Next-generation integrated high-power alternator/starter motors have
    already been incorporated in BMWs and Benzes, and in Ford and GM
    trucks; about half of all new cars will have them by 2010. These units
    will supply the car with abundant, efficiently generated electric
    power, in a much lighter package, that will provide a virtually
    instant engine start as well.

                             Cheap in the Gearbox

    This will set the stage for the last big step--the one already taken
    in monster trucks: Silicon and electric power will knock out the
    entire gearbox, driveshaft, differential, and related hardware;
    electric drives power the motors that turn the wheels. Power chips now
    make it possible to build high-power motors the size of a coffee can,
    and prices are dropping fast. When such motors finally begin driving
    the wheels, the entire output of the engine will have to be converted
    immediately into electricity before it is distributed, used, or stored
    throughout the car. It will take heavy-duty wiring and substantial
    silicon drives and electric motors to propel a hybrid-electric sport
    utility vehicle down a highway at 70 mph--but they'll be far smaller
    than the steel structures in today's powertrain. Cars will shed many
    hundreds of pounds, and every key aspect of performance will improve
    As this process unfolds, the engineering focus will shift inexorably
    toward finding the most efficient means of generating electricity
    on-board. Trains and monster trucks both use big diesel generators.
    Hybrid cars on the road today burn gasoline, but it's the fuel cell
    that attracts the most attention from visionaries and critics of the
    internal combustion engine. Remarkably elegant in its basic operation,
    the fuel cell transforms fuel into electricity in a single step,
    completely bypassing the furnace, turbine, and generator. In this
    scenario, mechanical engineering ultimately surrenders its last major
    under-the-hood citadel to chemical engineers.
    Much the same transformation is well under way in the factory. The
    19th-century factory was powered by a single driveshaft spanning the
    length of the building; belts and chains delivered power to each
    individual work bay. That primary mechanical driveshaft gave way to
    electric power long ago, with motors powering the lathe, drill, or
    milling machine in each workstation. But, by and large, the motors
    still connect to shafts and belts and compressors. As in the car,
    mechanical systems still control the last few meters of the

                              I, Sensitive Robot

    The new industrial robots, however, are complex configurations of
    electric servo motors; the electric power now runs right to the final
    threshold of where the power is needed. Packed with sensors, the
    robots are now precise, sensitive, and far more compact than any
    mechanical alternative. They are also far more flexible--they now can
    be instantly reconfigured to perform new tasks through software alone,
    a dramatic advance over previous systems that required hours of manual
    At the same time, high-power lasers--built around another family of
    recently developed semiconductors--are rapidly taking over functions
    previously viewed as mechanical. At kilowatt and megawatt power
    levels, lasers don't move bits, they move material. They fuse powdered
    metals into finished parts, without any machining, cutting, or
    joining. They supply ultra-fine heating, soldering, drilling, cutting,
    and materials processing, with fantastic improvements in speed,
    precision, and efficiency. They create thermal pulses that can blast
    metals and other materials off a source and deposit them on a target
    to create entire new classes of material coatings. They move ink in
    printers--not just desktop devices, but also the mammoth machines used
    to produce newspapers. They solder optoelectronic chips without
    destroying the silicon real estate around them, and they supply
    unequaled precision in the bulk processing of workaday materials--heat
    treating, welding, polymer bonding, sintering, soldering, epoxy
    curing, and the hardening, abrading, and milling of surfaces.
    Delphi has sold millions of its electric power steering units, which
    eliminate hoses, pump, and hydraulic fluid.

    Mechanical systems can be remarkably clever--just look at how a
    high-end mechanical watch powers and times the movement of hands
    around the watch face. In engines and machines of every description,
    much of the mechanical engineering is still devoted to imposing a
    desired logic on the flow of power. Until quite recently, EEs
    themselves relied on at least semi-mechanical systems to choreograph
    and order the flow of electricity. The huge electromechanical switches
    that phone companies used to route calls until the 1960s set up
    circuits by reconfiguring tapestry-like arrays of small,
    electromechanical switches--thousands and thousands of them, clicking
    away, day and night. But the advent of the transistor--invented by
    Bell Labs--changed all that. Semiconductors now choreograph the flow
    of all-electric
    (or photonic) power through our watches and our phone lines.
    Pushing semiconductors up the power curve took 20 years longer than it
    did to push them down. But it has now been done. And these
    fundamentally new technologies of "digital power" make possible an
    extraordinary new variety of compact, affordable, product-assembling,
    platform-moving, people- moving, and power-projecting systems that
    seem to be all but magical. They will inevitably infiltrate, capture,
    and transform the capital infrastructure of our entire energy
    economy--the trillions of dollars of hardware that convert heat into
    motion, motion into electricity, and ordinary electricity into highly
    ordered electron and photon power.
    One might say that the age of mechanical engineering was launched by
    James Watt's steam engine in 1763, and propelled through its second
    century by Nikolaus Otto's 1876 invention of the spark-ignited
    petroleum engine. We are now at the dawn of the age of electrical
    engineering, not because we recently learned how to generate
    light-speed electrical power, but because we have now finally learned
    how to control it.

    Peter W. Huber, a former mechanical engineering instructor at MIT, is
    a senior fellow of the Manhattan Institute. Mark P. Mills, a
    physicist, is a founding partner of a venture fund, Digital Power
    Capital. They are co-authors of The Bottomless Well (Basic Books,
    2005) .

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