Patent ID: 8001778
Filing Date: 2011-08-23
Classification: F02B,F02D,F02M,Y02T

Abstract:
1. A method of operating an engine coupled to a turbocharger, the engine having a high pressure exhaust gas recirculation (EGR) system for recirculating exhaust gas from upstream of a turbine of the turbocharger in an exhaust to downstream of a compressor of the turbocharger in an intake, the compressor having a recirculation passage with a compressor bypass valve coupled therein, the engine intake further having a throttle, the method comprising: during a first, low, engine airflow condition delivering at least some high pressure EGR to the intake, operating the throttle at a first throttle opening amount, and operating the compressor bypass valve at a first bypass opening amount to increase exhaust gas temperature and reduce compressor surge while maintaining turbocharger rotational speed; and in response to a driver pedal tip-in, reducing the first bypass opening amount to a second, lesser, bypass opening amount, increasing the first throttle opening amount to a second, greater, throttle opening amount, and reducing an amount of high pressure un-cooled EGR.