Abstract: A fuel and emissions control method for an internal combustion engine of a vehicle includes performing passive evaluation of individual cylinder fuel control (ICFC) multipliers by determining whether any of the ICFC multipliers exceed an ICFC multiplier threshold and, in response, determining first and second cylinder fuel-air (FA) imbalances during first and second passive evaluation stages, respectively, separated by a passive evaluation delay period, and based on a comparison between the first and second cylinder FA imbalances, either (i) passing, by the controller, the evaluation and maintaining, by the controller, the ICFC multipliers or (ii) failing, by the controller, the evaluation and (a) resetting, by the controller, the ICFC multipliers and (b) increasing, by the controller, the passive evaluation delay period and repeating the passive evaluation.

Abstract: Intake noise suppression techniques for a forced-induction engine having a low pressure exhaust gas recirculation (LPEGR) system configured to recirculate exhaust gas produced by the engine to an intake system of the engine via an EGR port comprise receiving, from a mass air flow (MAF) sensor of the engine, a MAF signal indicative of measured airflow through the intake system, detecting, based on the MAF signal, intake system conditions that are indicative of audible noise, and in response to detecting the detected intake system conditions that are indicative of audible noise, at least partially closing a differential pressure (dP) valve to mitigate or eliminate the intake system conditions and the corresponding audible noise, wherein the MAF sensor is disposed in the intake system upstream from the dP valve.

Abstract: Intake noise suppression techniques for a forced-induction engine having a low pressure exhaust gas recirculation (LPEGR) system configured to recirculate exhaust gas produced by the engine to an intake system of the engine via an EGR port comprise receiving, from a mass air flow (MAF) sensor of the engine, a MAF signal indicative of measured airflow through the intake system, detecting, based on the MAF signal, intake system conditions that are indicative of audible noise, and in response to detecting the detected intake system conditions that are indicative of audible noise, at least partially closing a differential pressure (dP) valve to mitigate or eliminate the intake system conditions and the corresponding audible noise, wherein the MAF sensor is disposed in the intake system upstream from the dP valve.