The Pumping Loss
A so-called "pumping loss" is also cited as causing extra work for the engine to do under partial load conditions because the pistons have to work harder to suck in the fuel-air mixture when the throttle position results in low intake-manifold pressure. Under this scenario, deactivating some of the cylinders allows the remaining active ones to have less manifold vacuum to overcome during the intake stroke.
Read more about this topic: Active Fuel Management
Famous quotes containing the words pumping and/or loss:
“It is by teaching that we teach ourselves, by relating that we observe, by affirming that we examine, by showing that we look, by writing that we think, by pumping that we draw water into the well.”
—Henri-Frédéric Amiel (1821–1881)
“Parents must not only have certain ways of guiding by prohibition and permission; they must also be able to represent to the child a deep, an almost somatic conviction that there is a meaning to what they are doing. Ultimately, children become neurotic not from frustrations, but from the lack or loss of societal meaning in these frustrations.”
—Erik H. Erikson (20th century)