Method and system for engine control

摘要

Methods and systems are provided for controlling exhaust emissions by adjusting an injection profile for different fuels injected into an engine cylinder from different fuel injectors during engine start and crank. By splitting fuel injection during start and cranking so that fuel of lower alcohol content is port injected and fuel of higher alcohol content is direct injected as one or multiple injections, the soot load of the engine can be reduced and fuel economy can be improved.

主权项

1. A method of operating an engine, comprising,
for a first combustion event since engine start, performing each of:
port injecting a first amount of a first fuel during a closed intake valve event; anddirect injecting a second amount of a second fuel over multiple injections of the first combustion event, the first fuel having a lower alcohol content than the second fuel.