POST FUEL INJECTION OF GASEOUS FUEL TO REDUCE EXHAUST EMISSIONS.

摘要

Methods and systems are provided for delivering gaseous fuel as multiple fuel injections split between an intake stroke, a compression stroke, and/or a power stroke to expedite exhaust catalyst heating during an engine cold-start. Fuel injected in the intake and compression stroke is ignited and combusted. The power stroke fuel injections are combusted in the exhaust port to increase exhaust temperature and pressure for faster catalyst light-off.