Early/late Exhaust Valve Closing
Early and late exhaust valve closing can also reduce emissions. Traditionally, the exhaust valve opens, and exhaust gas is pushed out of the cylinder and into the exhaust manifold by the piston as it travels upward. By manipulating the timing of the exhaust valve, engineers can control how much exhaust gas is left in the cylinder. By holding the exhaust valve open slightly longer, the cylinder is more emptied and ready to be filled with a bigger air/fuel charge on the intake stroke. By closing the valve slightly early, more exhaust gas remains in the cylinder which increases fuel efficiency. This allows for more efficient operation under all conditions.
Read more about this topic: Continuous Variable Valve Timing
Famous quotes containing the words early, late, exhaust and/or closing:
“Everyone in our culture wants to win a prize. Perhaps that is the grand lesson we have taken with us from kindergarten in the age of perversions of Dewey-style education: everyone gets a ribbon, and praise becomes a meaningless narcotic to soothe egoistic distemper.”
—Gerald Early (b. 1952)
“None will now find Cupid latent
By this foolish antique patent.
He came late along the waste,
Shod like a traveller for haste.”
—Ralph Waldo Emerson (1803–1882)
“Fear can supplant our real problems only to the extent—unwilling either to assimilate or to exhaust it—we perpetuate it within ourselves like a temptation and enthrone it at the very heart of our solitude.”
—E.M. Cioran (b. 1911)
“It is closing time in the gardens of the West and from now on an artist will be judged only by the resonance of his solitude or the quality of his despair.”
—Cyril Connolly (1903–1974)