Engines: Perfecting the Status Quo
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A PricewaterhouseCooper's AUTOFACTS Group's
Global Powertrain Strategies study - a near-term strategic analysis for
the automotive industry - shows how greatly the U.S. is out of sync with
the rest of the world. The numbers are almost reversed. We chose large
vehicles with large engines and automatic transmissions. The rest of the
world - Europe and Asia in particular - subsist on manual transmissions
and engines less than half the size of American iron. Given our fuel costs
almost 75 percent cheaper (it's all in the taxes, fuel production cost
is relatively consistent world wide) that's not likely to change. Europe
loves diesels, we don't,
Talks with global auto manufacturers, not surprisingly, didn't reveal any trade secrets. GM's Dave Pozniak, Staff Technical Consultant, says its new generation Overhead Valve engines (N.A.) respond to customers' need for low-cost, low-polluting, high-torque engines. Ford says they think the demands of future emissions and fuel consumption are best met with overhead cam power plants. GM says OHV engines make a smaller package, an undisputed fact. Fred Heiler, DaimlerChrysler's technical spokesman, says vehicle manufacturers can do anything, they just want governments to decide, hopefully on a global basis.
So what changes are afoot? Details. Details. Details. All manufacturers are concentrating on making every moving part lighter and stronger. Pozniak wonders how cast iron engines can be made as light as aluminum but stronger and quieter. Cast iron wears better, is naturally strong and quiet, and lots cheaper.
The Devil's In the Details
Chinu Bhavsar, Senior Staff Technical Specialist,
Advanced Engine Engineering, Ford Motor Company, says friction losses
may be addressed with new lubricants, like a OW20
The basics of engines, like making parts very
round of very flat, is immensely important. Unburned hydrocarbons hide
in the smallest crevice. The last great step in eliminating
Bhavsar says that "variable valve timing is happening - for emissions and fuel economy. Cost is coming down." Ford, Honda, Toyota, Lexus all use VVT and the added expense may become necessary for emissions and economy. "Camless valvetrains with electromechanical solenoid-operated valves take too much energy, 2 kilowatts, at this time," Bhavsar claims. Another problem, solenoids are noisy, slamming valves into their seats. "With high-powered starter/alternators, a camless valve train might become a reality."
Camless valve trains? Operated electrically? Absolutely. Precise selection of when fuel and air are taken in or exhausted from each cylinder will maximize efficiency. And the combined starter-alternator/generator-flywheel? Look for that to show up in less than five years, according to the electronics industry.
Borrowing from the Future
Drive-by-wire, an oft heralded technology,
has already appeared on some premium automobiles like Corvette. Like the
controls in an F-15 fighter, the lever or pedal you push,
All this electronic control will require more
powerful on-board computers - controllers as they're called. Today's engine
controllers use "look-up tables," (like a complex spreadsheet).
"A RISC Power PC (like IBM or Macintosh
desktop computers), 32 bit controller running at 50 mips (million instructions
per second) with a separate floating point math processor," Wilkie
says. Very similar to an older Macintosh Power PC 604, but less speedy.
Faster processors, like 300 MHz Pentium chips, have more speed - and heat.
Remember the camless valve train Chinu Bhavsar
mentioned? Wilkie says with computer controlled solenoids instead of a
valve train, "You're no longer bound by making an average camshaft
profile for an average load in an average engine."
That kind of computational control "requires
a sophisticated multi-processor computing environment. It means real time
dynamic engine control - and even calculating what's
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