Effectiveness of Mechanical Turbo Compounding in a Modern Heavy-Duty Diesel Engine

Abstract

Over the years, multiple engine manufacturers have offered mechanical turbo compounding on some engine models as a means to improve the efficiency of diesel engines. In theory, converting exhaust energy which would otherwise be wasted to shaft work seems like a technical path that no manufacturer should ignore especially in today’s world with the uncertainty of future CO2 emission regulations or fuel economy standards. This paper offers an independent examination of the effectiveness of the most recent implementation of mechanical turbo compounding on the Detroit Diesel (Daimler) DD15. In order to evaluate the effectiveness, an analysis procedure was developed for computing the tradeoff between power generated by the power turbine and losses incurred due to higher exhaust back-pressure as a result of the power turbine with consideration to the requirement for some minimum exhaust pressure to drive EGR.