Compressor Surge Mitigation in Turbocharged Spark-Ignition Engines without an Anti-Surge Control System during Load-Decrease Operation

Automotive manufacturers are showing an increasing preference for hybrid powertrains based on advanced gasoline engines. The most extended solution to improve fuel economy in these engines consists downsizing with direct injection, while turbocharging is required compensate the consequent power loss. However, associated different issues, such as compressor surge. It can appear during fast throttle closings (tip-outs), when engine air flow abruptly reduced. A usual strategy manage this kind of maneuver installation anti-surge valve (ASV) that connects inlet and outlet approaching surge limit. In pursuit cost reduction, removal ASV system was assessed research. To end, tip-outs without were tested a turbocharged equipped low-pressure EGR loop, two strategies analyzed: closure optimization reduction pressure through intake flap (located upstream increase rate). instantaneous its time derivative used detection. Experimental revealed applying certain closing combined optimized actuation led torque decrease, similar observed reference case ASV, instabilities.