A Comprehensive Study on Euro 6 Turbocharger Selections and Its Deterioration with Closed Crank-Case Ventilation in Heavy Commercial Vehicles

Euro 6 emission norms are getting implemented in India from April 2020 and it is being viewed as one of the greatest challenges ever faced by the Indian automotive industry. In order to achieve such stringent emission norms a good strategy will be to optimize the engine out emission through in cylinder emission control techniques and a right sized after treatment system has to be used for this optimized engine. There exist several factors and trade-off between these should be established for in cylinder optimization of emissions. Since the turbocharger plays an apex role in controlling both the performance and engine out emissions of a CI engine, turbocharger selection is a crucial step in the development of new generation of Euro 6 engines in India. Such engines are equipped with additional actuators such as Intake Throttle Valve and Exhaust Throttle Valve and combination of these flap operations with turbocharger output plays a prominent role in controlling performance and emission. This study focusses on the use of different AVU (Air Valve Unit) controlled waste gate turbochargers from different suppliers and how it’s matched with the engine performance requirements. Hindrances such as fluctuations in boost pressure due to the waste gate operational inconsistency and deterioration of turbo efficiency due to closed (positive) crankcase ventilation over time were faced during evaluation, and the solution to such problems are also mentioned in this study. It was found that the drop in efficiency of compressor can be as high as 5 - 10% without a proper oil separator set up and is verified with back to back tests.