Abstract: To provide a filter element for an air cleaner unit for an engine including an elongated rectangular contour as seen in a plan view and having a corrugate sectional contour as seen from the front side, the one end side of the corrugated sectional contour is collected on the central side of the filter element, the other end side of the same is expanded to exhibit a substantially circular contour, the opposite ends of the filter element as seen in the circular contour are connected to each side by the side-by-side relationship to exhibit a substantially annular contour as seen in a plan view, and subsequently, a cover member designed to have a conical-shaped or a spinner-shaped contour is attached to the upper surface side and/or the lower surface side at the central part of the filter element main body.

Abstract: A filter element is constructed such that a filter material having a corrugated sectional surface is formed in the shape of a cylindrical housing, and an upper opening portion of the cylindrical housing is kept closed, and an lower opening portion is connected to an air suction duct. A row of hills and valleys of the corrugated sectional surface is formed with a certain front angle relative to the wall surface of the cylindrical casing.

Abstract: An air filter having a tapered cylindrical filter member is attached to an engine air intake at its larger end and has an inverted frusto-conical member inside the opposing smaller end for reducing turbulent air flow through the air filter. The inverted frusto-conical member includes an air filter portion which may be the tapered walls of the inverted frusto-conical member, or the smaller flat end of the inverted frusto-conical member. A funnel inside the larger end of the tapered cylindrical filter member further reduces turbulence of the air flow from the air filter into the engine air intake.

Abstract: A method and apparatus for increasing the internal height of a casing of an air cleaner for an engine in order to accommodate a larger air filter. A larger air filter is accommodated by increasing the distance between the upper and lower members of the casing by increasing the thickness of the air filter's peripheral flange or by adding a spacer element between the upper and lower members.