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| Lighting-Bolt Iqnition |
Conventional spark plugs struggle to fire lean intake charges that are
laced with heavy doses of exhaust gas. To prevent misfiring,
Mercedes-Benz uses several sparks per combustion cycle in its new
high-compression 3.5-liter V-6. An alternative approach under
development by Federal-Mogul is an Advanced Corona Ignition System,
which sprays several ion streams into the combustion chamber like a
miniature lightning storm. This high-frequency system occupies the same
space as a conventional coil-and-plug ignition and has demonstrated a
10-percent mileage gain. Since this eliminates electrode arcing, which
shortens the life of conventional plugs, ignition-system longevity
should be improved.
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| Cylinders on the Chopping Block |
BMW and Mercedes-Benz reintroduced four-cylinder engines to their U.S.
lineups after years of absence. Volvo is phasing out five- and
six-cylinder engines in favor of threes and fours. Both Ford and GM have
unveiled 1.0-liter three-cylinders slated for global duty. These and
other makers are exploiting strides made with turbocharging and direct
injection to deliver equivalent power from fewer cylinders and fewer
cubic inches. The smaller, harder-working engines are cheaper, lighter,
and significantly more fuel efficient. But don’t count on Corvette or
Ferrari turbo V-6s—both brands have denied the existence of such engines
for now.
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