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Engines: Perfecting the Status Quo
Thom Cannell

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Marching to a Different Drummer

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,
at least not at the moment.

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
(versus today's 10W30 oils) lubricant containing olybdenum disulfide. Parasitic or drag losses from pumping oil and water through the engine waste energy and demand smaller,
more efficient pumps.

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
unburned hydrocarbon emissions was made by moving the piston ring - it's seal - nearer the top of the piston. Now Ford is using head gaskets - the seal between the engine block and cylinder head - made of metal less than a millimeter thick. And they're looking at smaller spark plugs with no crevices to trap unburned gasses.

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,
pull or step on will feel the same, but no longer be mechanically connected to the engine. Instead, the gas pedal, brake or gearshit will activate a computer. Ford's Bhavsar says this can improve drivability, improves control of emissions, increases fuel economy, and better controls some transient forces for decreased vibration.

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).

"If (it's) this rpm or load, than that fuel schedule should be optimum." Sophisticated guesses instead of facts. Brian Wilkie, corporate vice president and general manager of the Advanced Vehicle Systems Division of Motorola says the next generation of engine controllers will use information gathered in real time, not from look-up tables.

"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. "Trying to
fit one of those little heat dissipating fans on a circuit board doesn't work in an engine controller," Wilkie says. These new engine controllers will use laboratory-built mathematical physics models to approach perfect timing of intake and exhaust with today's variable valve timing. With new techologies, that control will increase.

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
optimum for an engine that's hundreds or thousands of hours old. (It requires) systems that 'learn.' They're even talking about spark plus that measure the ionization (combustion products) in each combustion chamber. Today that technology costs hundreds of dollars per spark plug!"

Next : Perfected Precision

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