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:
“I doubt that I would have taken so many leaps in my own writing or been as clear about my feminist and political commitments if I had not been anointed as early as I was. Some major form of recognition seems to have to mark a woman’s career for her to be able to go out on a limb without having her credentials questioned.”
—Ruth Behar (b. 1956)
““Men there were and men there be
But never men so many
Chief enough to marry me,”
Thought the proud late Annie.”
—Gwendolyn Brooks (b. 1917)
“Language is like soil. However rich, it is subject to erosion, and its fertility is constantly threatened by uses that exhaust its vitality. It needs constant re-invigoration if it is not to become arid and sterile.”
—Elizabeth Drew (1887–1965)
“And if the stage-dark head rehearse
The fifth act of the closing night,
Why, cut it off, piece after piece,
And throw the tough cortex away....”
—Allen Tate (1899–1979)