Abstract: A silencer includes an air passage tube having an air inlet for introducing air thereinto, and a side branch tube connected to the air passage tube and having a closed end for attenuating noise produced by the air introduced into the air passage tube. The side branch tube may be either a flexible tube or have a flexible portion for allowing convenient bending and mounting thereof in the available space. The side branch tube may comprise a pair of different tube portions connected to each other. The side branch tube may have a water drain hole defined in its lowermost portion and preferably the cross-sectional area of the water drain hole is no greater than 1% of the cross-sectional area of the side branch tube. The side branch tube serves to attenuate high-frequency noise and the silencer may additionally include a resonator chamber for attenuating low-frequency noise.

Abstract: An air cleaner case is installed by an attachment device on the back of an intake manifold having a plurality of branch tubes extending forwardly toward the intake ports, respectively, of an engine cylinder head. The attachment device includes upper and lower attachment arms on the air cleaner case extending substantially horizontally and upper and lower seats on the intake manifold. The upper and lower attachment arms are substantially vertically detachably coupled to the upper and lower seats, respectively. The lower attachment arms are coupled to the lower seats by vertical pins mounted on the lower seats and the upper attachment arms are coupled to the upper seats by vertical bolts. The air cleaner case can easily be attached and detached vertically even in the limited space surrounding the air cleaner case behind the intake manifold.

Abstract: A plate-like air cleaner element housed in an air cleaner case divides the interior of the air cleaner case into an uncleaned-air chamber and a cleaned-air chamber. The air cleaner element can filter uncleaned air introduced in the uncleaned-air chamber to deliver cleaned air into the cleaner-air chamber. A plurality of partitions are disposed in the uncleaned-air chamber and jointly define an undulating air path in the uncleaned-air chamber for guiding the introduced uncleaned air therealong substantially over the entire flat surface of the air cleaner element, so that the uncleaned air can pass through the air cleaner element over a relatively large effective filtering area thereof. The air cleaner also includes an air guide plate disposed in the uncleaned-air chamber for guiding and straightening the incoming flow of uncleaned air deeply into the uncleaned-air chamber before the air is guided to flow toward the air outlet.

Abstract: An air cleaner device is disclosed of the type comprising a cleaner element assembly disposed in a cleaner case which is divided into an uncleaned air chamber and a cleaned air chamber. The air cleaner element assembly includes a cleaner element, and a seal joint hermetically sealing the cleaned air chamber and integrally connected to the cleaner element. The cleaner element can thereby be easily mounted in the cleaner case, and the filtered air can be provided to the intake system without being contaminated by uncleaned air.