INCREASING CRANKCASE VENTILATION FLOW RATE VIA ACTIVE FLOW CONTROL

摘要

Methods and systems are provided for coordinating throttle bypass flows from brake booster vacuum reservoir, a fuel vapor purge system, and a crankcase ventilation system via active, electrical control of a crankcase ventilation valve. In one example, a method may include actively opening the crankcase ventilation valve to allow crankcase ventilation flow into the engine during conditions in which doing so will not result in engine air flow rate and/or engine fuel flow rate exceeding desired rates. Priority is given first to brake booster replenishment, then to fuel vapor purging, and then to crankcase ventilation during conditions where all three throttle bypass flows are desired.

主权项

1. A method for an engine comprising:
electrically controlling a crankcase ventilation valve to selectively enable crankcase ventilation flow into an engine intake downstream of a throttle based on desired engine air and fuel flow rates, current engine air flow rate contributions from a brake booster, and current engine air and fuel flow rate contributions from a fuel vapor purge system.