US 4,461,248 A · Broad torque band producing intake manifold for an internal combustion engine

Abstract

An intake manifold for internal combustion engines has a plurality of independent runners emanating from a central plenum. Different sets of runners have different cross-sectional areas matched to flow velocity through the manifold at maximum torque and desired engine speeds to produce a wide high torque band. The length of each runner of each set corresponds to a harmonic frequency of the fundamental frequency of air at standard temperature, but the frequency differs for each runner set. Within each set, runner cross-sectional areas are constant throughout their length. In one embodiment, the runners curve from a plenum to their exits and in the curve each runner's cross section is regular trapezoidal with the small side of the trapezoid on the inside curve and the shape of the trapezoid effecting constant static pressure throughout the cross section.

Claims26

Dependent claims

In an intake manifold for combustion air for a reciprocating internal combustion engine of the type where combustion air velocity through the manifold is a direct function of engine speed, an improvement comprising:

(a) a first set of runners of equal length and cross-sectional area, the length of each first set runner corresponding to a harmonic frequency of the fundamental frequency of air at standard temperature and the cross-sectional area of each first set runner being such that at a first engine speed combustion air velocity through the runner is substantially equal to the velocity at engine maximum torque;
and
(b) a second set of runners of equal length and cross-sectional area, the length of each second set runner corresponding to a harmonic frequency of the fundamental frequency of air at standard temperature different from that for the first runner set and the cross-sectional area of each second set runner being such that at a second engine speed, substantially different from the first engine speed, combustion air velocity through the runner is substantially equal to the velocity at engine maximum torque.

An improved intake manifold for an internal combustion engine comprising:

(a) means defining a plenum for receiving a fuel and air mixture from a carburetor;
(b) means defining a first set of runners from the plenum, each runner of the first set having a length corresponding to a harmonic frequency of the fundamental frequency of air at atmospheric temperature which produces resonance at a first engine speed, and a cross-sectional area that produces a velocity of air in the runners at the first engine speed corresponding to the velocity of air at engine speed maximum torque;
and
(c) means defining a second set of runners from the plenum, each runner of the second set having a length different from the length of the runners of the first set and corresponding to a different harmonic frequency of the fundamental frequency of air at atmospheric temperature than the first set and which produces resonance at a second engine speed substantially different from the first, and a cross-sectional area that produces a velocity of air in the second runners at the second engine speed corresponding to the velocity of air at engine speed maximum torque;
whereby, the two runner sets each produces relatively high engine torque at the engine speeds at which they produce resonance.

2 more elements

Dependencies are inferred from the claim text.

Broad torque band producing intake manifold for an internal combustion engine

Life of this patent

Broad torque band producing intake manifold for an internal combustion engine

Life of this patent

Abstract

Claims26