Idle speed control devices

摘要

A throttle valve (12) is provided in an intake air passage (11) of a throttle body (10) and serves to control the air flows rate that is supplied into a combustion chamber of an internal combustion engine. A valve housing (21) is joined to the throttle body (10). A communication passage (22) is formed in the valve housing (21). A branching side passage (13a) and a joining side passage (13b) are formed in the throttle body 10 and, together with the communication passage (22) in the valve housing (21), form a bypass structure (13) that bypass the throttle valve (12). A valve seat portion (23) is formed on the valve housing (21) in the communication passage (22). A valve (25) is provided in the valve housing (21) and serves to control the opening area of the valve seat portion (23). A lattice (50) is disposed downstream of the valve seat portion (23) in the bypass structure (13). The lattice (50) may be replaced with other structures adapted to reduce or prevent turbulent airflow downstream of the valve seat portion (23). Preferably, such structure generates a laminar airflow.