Performance improvements of turbocharged engines with the use of a PTP turbo blanket
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Efforts in R&D of modern vehicles are highly focused on improvements of the overall efficiency. The engine still has potential for better performance which not only implies pure efficiency considerations but also the power output specific to the engine size and weight. Turbochargers are a key technology. However, a significant amount of exhaust energy is lost through the turbine housing, and thus cannot be utilized to boost the intake air. If a certain portion of the lost heat can be conserved, however, the process in the turbine can be shifted more towards adiabatic expansion which, in theory, is the ideal case. The Engines Research Program at The University of Texas at Austin conducted comparison tests of a PTP turbo blanket. The baseline engine was a Cummins 6.7 Turbocharged Diesel Engine hooked up to a Superflow SF-901 dynamometer. A series of steady-state points were obtained as well as three instantaneous load tip-in scenarios (hard acceleration transients) in order to test for changes in transient response due to the turbo blanket. In addition to seven thermocouples that we installed around the turbine we used the open ECU software to log a set of about 30 engine parameters. The recorded data was first analysed with respect to the performance of the turbocharger alone. On the steady-state cases, the temperature increase of the turbine housing was significant while we did not measure a major increase of the oil temperature in the exit of the center section. According to these findings, oil “coking” was not a concern since the temperature difference of the oil with and without the turbo blanket was negligibly small. The boost pressure increase corresponded well with the higher turbo shaft speeds when the turbo blanket was applied. Second, tip-in transients were performed to examine the difference in performance during a hard acceleration. The turbo spooled up more rapidly with the turbo blanket installed in comparison to the baseline configuration. In all cases this resulted in an improved boost performance in the intake and a significant time-to-torque advantage of the engine with a torque benefit of up to 140 Nm while the acceleration was improved by 200-250 rpm for most of the tip-in event. This report presents detailed data regarding experiments in which the turbocharger and the engine are treated as an integrated system with a PTP turbo blanket applied in comparison to the baseline configuration for which the turbine housing is not insulated.