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The environmental impact of internal combustion engines has led to increasing governmental regulations regarding the emissions and fuel economy performance of internal combustion engines. The DI Diesel engines, having the evident benefit of a higher thermal efficiency than all other engines, have served for both light- duty and heavy-duty vehicles. But, direct injection diesel engines emit more particulates and oxides of nitrogen than their counterpart and that is a challenge. The NOx+HC limits for CEV BSIII regulations is 4.00 g/ Kw-Hr,3.8 g/Kw-Hr with deterioration factor[DF] against the 10.50 g/Kw-Hr of CEV BSII regulations, which is over 60% reduction in gaseous emissions. Now after this stringent targets defined it is essential to understand the NOx formation.

Engine manufacturers and product designers are currently under significant pressure to reduce fuel consumption, emissions, and noise from two-stroke engines. Improved engine breathing goes a long way toward overcoming these challenges by providing better charge delivery, complete exhaust gas scavenging, and minimal fuel short-circuiting. Reed valve motion and the resulting gas flow are highly coupled phenomena. Understanding and controlling these dynamics and their interactions is critical to effective intake breathing. A comprehensive effort to model reed valves at a level sufficient for engine design using engine simulations is still incomplete. This work is focused on the assessment, development and validation of a reed valve model suitable for engine simulations. In this work, a representative two-stroke engine reed valve is modeled in a detailed fluid/structures, multi-physics CFD code which fully resolves both the flow-field and the details of the deflecting reed plate.

During the design stage, certification testing, or in field problem solving, t is of value for engine designers and engineers to have an understanding of how robust the engine design is to variation in the manufacturing process, in-use wear, controller and the testing processes. In this paper, a sensitivity analysis is performed on a parametric GTpower diesel engine model and using Robust Design methods NOx defects are reduced. Sensitivity analysis is conducted using a Plackett-Burman DOE. The DOE is performed on a 6 cylinder, direct-injection, turbocharged diesel engine model in GTpower, while Minitab is used for the experimental design and the factorial sensitivity analysis. It was found that the NOx population distribution was unacceptably high, yielding a 7.4% defect rate relative to an upper control limit of 5 (g/kw-hr).