Engine with charge equalizing intake manifold

Claim 1

In combination in an internal combustion engine, means defining four variable volume combustion chambers aligned longitudinally and grouped in two longitudinally spaced pairs of chambers, each chamber having an intake port with the intake ports of each pair of chambers being closely spaced longitudinally at their ends for connection with a common manifold runner and the ends of the closely spaced pairs of ports being longitudinally spaced a substantial distance apart, means for operating said chambers in sequential cycles including intake events which occur sequentially in the chambers of each pair and alternately in the separate pairs of chambers, an intake manifold having a central plenum and a pair of runners extending oppositely from said plenum, each of said runners being connected with one of said spaced pairs of intake ports such that the sequential chamber intake events occurring alternately in the spaced pairs of chambers cause alternate pulses of fluid motion in the manifold runners with the flow dynamics tending to cause delivery of a relatively smaller charge to the first one of the sequentially timed combustion chambers of each pair, and the improvement wherein the ends of the manifold runners are offset at their connections with their respective pairs of intake ports in directions toward said first timed chambers, such that the runners are more directly aligned with the intake ports of said first timed combustion chambers of the sequentially timed pairs than with the intake ports of the last timed chambers of such pairs to an extent to offset the manifold pulsing effect and tend to equalize charge distribution.