Methods and systems for low-pressure exhaust gas recirculation

摘要

A method for controlling air flow through a compressor recirculation passage, comprising: during a first condition: reducing air flow through the compressor recirculation passage based on a margin, the margin based on a rate of air flow at a compressor inlet, a rate of air flow through the compressor recirculation passage, and a rate of EGR flow. In this way, the CRV recirculation flow may be controlled to be less than the amount that could potentially backflow into an air filter disposed in the air intake passage, thus preventing EGR contained in the CRV recirculation flow from fouling the air filter with soot, oil and water.

主权项

1. A method for controlling air flow through a compressor recirculation passage of a turbocharger in an internal combustion engine, comprising:
during an engine operating condition;
reducing air flow through the compressor recirculation passage by adjusting a valve based on an air capacity margin, the margin based on a rate of air flow at a compressor inlet, a rate of air flow through the compressor recirculation passage, a rate of exhaust gas recirculation (EGR) flow, a volume of an air intake passage that is upstream of the compressor recirculation passage, a pressure in a first section of the air intake passage, and a pressure in a second section of the air intake passage, the first and second sections separated by an air intake throttle.