Twin Plug Combustion
Some engines, since the earliest petrol engines, have used twin spark systems. These have twin spark plugs, supplied by separate sources. There may be several reasons for this: reliability (typically aircraft), starting (e.g. Model T), or better combustion performance by initiating the flamefront at opposing points simultaneously (e.g. Alfa Romeo). None of these are counted as wasted spark systems, as their sparks all take place after the useful compression stroke, rather than "wasted" in the exhaust stroke.
Read more about this topic: Wasted Spark
Famous quotes containing the words twin and/or combustion:
“If they be two, they are two so
As stiff twin compasses are two;
Thy soul, the fixed foot, makes no show
To move, but doth if th’ other do.”
—John Donne (1572–1631)
“The night has been unruly. Where we lay,
Our chimneys were blown down, and, as they say,
Lamentings heard i’ th’ air, strange screams of death,
And prophesying with accents terrible
Of dire combustion and confused events,
New-hatched to the woeful time.”
—William Shakespeare (1564–1616)