Patent ID: 8137424

Claim:
An air cleaning device for an internal combustion engine, comprising: an air cleaner chamber divided into a dust chamber formed on a lower side and a clean chamber formed on an upper side while interposing a cleaner element therebetween in a vertical direction, wherein an outlet of an air introduction passage having an air introduction port is opened to the dust chamber, an inlet of an air discharge passage is opened to the clean chamber, wherein a chamber wall of the air cleaner chamber includes a bottom wall opposed to the cleaner element in the vertical direction and a pair of side walls extending from the bottom wall, the pair of side walls comprises a first side wall to which the air introduction passage is connected and a second side wall which is opposed to the first side wall in an opposing direction while interposing the cleaner element therebetween, the air introduction passage has a curved passage which is divided into a curved inside branch passage and a curved outside branch passage by a partition wall, a first path length from the air introduction port to the outlet via the curved inside branch passage is set to be shorter than a second path length from the air introduction port to the outlet via the curved outside branch passage, the curved passage is curved in a direction crossing the opposing direction toward an upstream side, as viewed in the vertical direction, first and second deflecting portions are provided in the dust chamber to deflect upward flows of air flowing to the dust chamber from the outlet via the curved inside branch passage and the curved outside branch passage, respectively, to thereby direct the flows of air to the cleaner element and the second deflecting portion is positioned closer to the outlet than the first deflecting portion in the opposing direction.