Chopper assembly for an agricultural harvester

A chopper assembly for an agricultural harvester, the chopper assembly comprising:

• a chopper drum comprising a plurality of chopper knives arranged along the longitudinal direction of the drum, wherein the chopper drum is rotatable about a longitudinal rotation axis,
• a set of counterknives,
• a pair of sidewalls oriented transversely with respect to the longitudinal rotation axis of the chopper drum, the chopper drum being rotatably mounted between said sidewalls,
• an inlet opening and an outlet opening, each opening comprising a first and second lateral side arranged along the respective sidewalls,
• at least one guide surface mounted on at least one of the sidewalls, wherein said at least one guide surface extends between an upstream edge lying substantially in a plane of said at least one of the sidewalls and a downstream edge removed from said at least one of the sidewalls, and wherein said at least one guide surface is inclined relative to said at least one of the sidewalls so as to guide plant material away from said at least one of the sidewalls and in a direction of the chopper knives located closest to said at least one of the sidewalls,
• wherein the chopper assembly is configured to:
• (i) receive through said inlet opening a stream of the plant material advancing between the sidewalls,
• (ii) cut the plant material into particles, and
• (iii) eject the particles through the outlet opening.