To provide an intake A/F controller for an outboard engine, by which an exhaust gas A/F can be accurately controlled to a required target vague, whether in the case that an acceptable range of a purifying rate of a catalytic converter is set to a relatively large range in consideration of an engine output, or in the case that the setting range is shifted to a rich side of the A/F in much consideration of the engine output.
A secondary air passage, which supplies secondary air for adjusting an A/F of an air-fuel mixture, is connected to a carburetor of an engine intake system, while a duty control valve 68 is connected to the secondary air passage. A duty control unit 92, which controls a duty ratio of a pulse applied to a coil 76 of the duty control valve 68, is connected to the duty control valve 68, while an exhaust emission system is mounted with an LAF sensor 94 which detects an A/F of exhaust gas and outputs a detection signal proportional to the A/F of the exhaust gas to the duty control unit 92.
| WO/2018/104034 | EXHAUST GAS AFTERTREATMENT DEVICE |
| JPH0791238 | EXHAUST EMISSION CONTROL DEVICE FOR ENGINE |
| JP2009068422 | ENGINE EXHAUST STRUCTURE OF WORK MACHINE |
KAWASAKI TOYOKAZU
FUKUDA YOSHIHIKO
