Co-Surge in Bi-Turbo Engines: Measurements, Analysis and Control
2014 (English)In: Control Engineering Practice, ISSN 0967-0661, Vol. 32, 113-122 p.Article in journal (Refereed) Published
In parallel turbocharged V-engines, with two separate air paths connected before the throttle, an oscillation in the flow can occur.If the compressor operates close to the surge line, typically during low speed and high load, and a disturbance alters the massflow balance, the compressors can begin to alternately go into surge. This phenomenon is called co-surge and is unwanted due tohigh noise and risk for turbocharger destruction. Co-surge is measured on a test vehicle in a chassis dynamometer and the systemanalyzed and modeled using a mean value engine model. The investigation shows that the alternating compressor speeds have animportant role in the prolonged oscillation. A reconstruction of the negative flow from measurements is made and compared tosimulation results, showing similar amplitudes, and supports the model validation. A new co-surge detection algorithm is presented,suitable for a pair of sensors measuring either mass flow, boost pressure or turbo speed in the two air paths. Furthermore, a newcontroller is proposed that uses a model based feedforward for the throttle, together with wastegate actuation to force the compressorspeeds together and improve balance at the recovery point. This has shown to be sufficient with moderate to high pressure ratiosover the throttle, only for zero or very low pressure drop the use of bypass valves are necessary. The advantage of not opening thebypass valves is a smaller drop in boost pressure which also reduces the torque disturbance. The performance of the controller is evaluated both in simulation and in the test vehicle.
Place, publisher, year, edition, pages
Elsevier, 2014. Vol. 32, 113-122 p.
Compressor surge, surge detection, surge control, engine modeling, engine control
IdentifiersURN: urn:nbn:se:liu:diva-105686DOI: 10.1016/j.conengprac.2014.08.001ISI: 000344435200009OAI: oai:DiVA.org:liu-105686DiVA: diva2:709524