Cross-port air flow that improves engine fuel economy and reduces pumping losses during part-throttle operation can be implemented in various types of internal combustion engine systems using ports that interconnect the intake ports of different cylinders, thus allowing different cylinders to share combustion air. Cross-port air flow is commenced during part-throttle engine operation to disrupt the primary combustion air flow from each throttle to its associated cylinder, which reduces charge density and engine power. The engine compensates for the reduced power by incrementally opening the throttles, thus increasing the primary combustion air flow, reducing pumping losses and improving fuel economy.

An air intake device includes: a valve body which includes a rotating shaft; a bearing member which rotatably supports the rotating shaft of the valve body; and an air intake port which includes a concave portion on which the bearing member is disposed, wherein the bearing member includes a positioning portion for positioning the bearing member with respect to the concave portion of the air intake port, facing surfaces which extend from the positioning portion along the concave portion of the air intake port and face each other in an inward radial direction of the rotating shaft with respect to the concave portion, with a gap therebetween, and protruding portions which protrude toward the concave portion of the air intake port from the facing surfaces and seal the gap.

An apparatus for adjusting power and noise characteristics of an internal combustion engine comprises a wall configured to define an engine cylinder that includes a bore and a compression relief passage. A compression relief valve is configured to selectively adjust fluid flow capacity of the compression relief passage. A manifold is configured to be in fluid communication with the exhaust passage and includes an exhaust bypass valve to permit exhaust to at least partially bypass a noise suppressor. Operational characteristics of the engine can be adjusted along a range that extends from a first set of operational characteristics present when both the compression relief valve and the exhaust bypass valve are in a fully open position to a second set of operational characteristics present when both the compression relief valve and the exhaust bypass valve are in a fully closed position.

A spin tube assembly for an engine air cleaner is provided. The spin tube assembly includes a housing, a spin tube panel, a plurality of spin tubes and at least one constrictor. The plurality of spin tubes are supported on the spin tube panel in parallel relation to one another. Each spin tube of the plurality of spin tubes includes a helical element causing air entering the spin tube to rotate such that particles within the air are moved by centrifugal action outwardly against a wall of the spin tube. At least one spin tube of the plurality of spin tubes has a constrictor upstream from the helical element thereof. The constrictor causes a localized restriction of air entering the at least one spin tube compared to the spin tubes without constrictors. Methods of use and configuration are also provided.

Cross-port air flow that improves engine fuel economy and reduces pumping losses during part-throttle operation can be implemented in various types of internal combustion engine systems using ports that interconnect the intake ports of different cylinders, thus allowing different cylinders to share combustion air. Cross-port air flow is commenced during part-throttle engine operation to disrupt the primary combustion air flow from each throttle to its associated cylinder, which reduces charge density and engine power. The engine compensates for the reduced power by incrementally opening the throttles, thus increasing the primary combustion air flow, reducing pumping losses and improving fuel economy.

An air intake device includes: an air intake port; and a valve that includes an elastically deformable seal portion disposed in Ha side end portion, and switches between flow paths of the air intake port by being turned around a turning shaft, wherein the side end portion of the valve is provided with a curved side end portion that extends from one end portion side to the other end portion side along an extension direction of the turning shaft while being curved.

A variable intake system includes a pair of surge tanks connected in a communicating manner to a main intake pipe through a low speed communication pipe and a high speed communication pipe, a middle speed communication pipe for connecting the pair of surge tanks, and a noise reducing member integrally provided at the middle speed communication pipe to reduce noise.

An internal combustion engine includes: an engine body (10) having at least one cylinder; and an air-supply manifold (4) including an adjustment pipe (12). The length of the adjustment pipe is set so that a first pressure wave (14A) propagating from the air-supply manifold toward the adjustment pipe and a second pressure wave (14B) propagating from the adjustment pipe toward the air-supply manifold have opposite phases from each other at the cylinder.

A fresh air supply system may include a housing that may include an upper housing part and a lower housing part and delimiting a housing interior. The system may also include at least one bearing part arranged in the housing interior and a shaft at least partially arranged and rotatably mounted in the at least one bearing part. The at least one bearing part, in a cross-section of the housing perpendicular to a rotation axis of the shaft, may be structured in a pot-like manner including a pot base. The lower housing part may include a lower housing part extension resting against a projection of the pot base such that a clamping connection is formable. The upper housing part may include at least one upper housing part extension which the at least one bearing part may rest against.

Disclosed herein is an actuator for an intake manifold, wherein the actuator may include: a housing having a negative pressure space; an operating unit operated by the pressure of air introduced into and discharged from the negative pressure space, and rotating the variable valve; an exhaust flow path connected to an external negative pressure supply source; an intake flow path receiving external air which raises the pressure of the negative pressure space; a spool hole formed in the housing so as to communicate with the exhaust flow path and the intake flow path; an air entry and exit flow path formed in the housing so as to communicate with the negative pressure space and the spool hole; a valve body selectively opening/closing the exhaust flow path and the intake flow path; and a solenoid unit operating the valve body.