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A technical approach to reduce NOx and to minimize the fuel consumption caused by the DeNOx aftertreatment system was introduced. The NEDC mode test of the HMC (Hyundai Motor Company) DeNOx system was done with a Euro 5 vehicle (ETW (Equivalent Test Weight) = 1,810 kg, 143 kW, 430 N⋅m), which resulted in that the Euro 6 legislation standards were met. The NOx and HC emissions were, respectively, measured to be 0.059 g/km and 0.087 g/km with the hydrothermal-aged catalysts, and CO₂ was increased by ≺ 4%.

This paper presents a 2.5L V6 aluminum cylinder block engine that has been developed for use in the next HYUNDAI SONATA vehicle. The major objective in developing this new engine was to achieve high power,especially high torque at low to mid speed range, quiet engine operation, reliability and good fuel economy. The basic construction of the engine is characterized by its 60-degree V6 configuration, compact combustion chamber and simple variable intake systems. The new engine has been designed to comply with the tougher TLEV emission standard, OBD-II requirements and California's new evaporative emission standards. This paper will introduce various technologies used in this engine that increased engine performance while reducing emission and improving fuel economy and NVH characteristics, and will discuss the engine construction, principal component parts, major development objects and test results.

Future emission limits of diesel engines require additional effort to develop advanced after-treatment devices. The Urea-SCR system is a promising device to reduce NOx emissions. The purpose of this work is to reduce NOx emissions from a Light Duty Vehicle (LDV) with a Urea-SCR (Selective Catalytic Reduction) system, a Catalytic Particulate Filter (CPF), and a Diesel Oxidation Catalyst (DOC). The purpose of the development is to analyze the atomization characteristics of the urea solution and to optimize the flow path shape in front of the SCR catalyst for uniform reductant (NH3) distribution. Additionally, the development purpose is to determine the strategy for urea solution injection quantity and to verify the performance of the Urea-SCR system on the vehicle. The NO2/NOx ratio plays a pivotal role in reducing NOx with Urea-SCR system. Although NO is converted into NO2 through the DOC, the NO2/NOx ratio is reduced due to the CRT (continuous regenerating trap) effect in the CPF.