Co-Surge Detection and Control for Bi-Turbo Engines with Experimental Evaluation
A V-type engine with a bi-turbocharger configuration utilizes the exhaust energy
well which gives a fast torque response. An unwanted instability, called co-surge, can occur in
such engines where the two interconnected compressors alternately go into flow reversals. If co-
surge occurs, the control system must quell the oscillations with as little disturbance in engine
torque as possible. A model of a bi-turbocharged engine is presented, combining a mean value
engine model and a Moore-Greizer compressor model for surge. The model is validated against
measurements on a vehicle dynamometer, showing that it captures the frequency and amplitude
of the co-surge oscillation. The model is used to develop detection and control strategies for
co-surge that rapidly returns the turbo to a stable operating point. Both simulations and
experimental evaluation on the vehicle show that the developed strategies are successful in
rapidly detecting and quelling co-surge. The selection of actuators is also studied. With no or
small pressure drops over the throttle, it is necessary to use the bypass valves. However, for
operating conditions with moderate and high pressure drops over the throttle, it is shown that
it is sufficient to only open the throttle. This has the advantage, compared to opening the bypass
valves, that it reduces the drop in boost pressure and thus reduces the drop in engine torque.
Andreas Thomasson and Lars Eriksson
2013
Informationsansvarig: webmaster
Senast uppdaterad: 2021-11-10
LiU Homepage
