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Development, optimization and calibration of diesel engine parameters have become extremely complex, because the recent technology engines have too many parameters and their interactions, which play significant role in controlling emissions. To reduce development time and cost, a systems approach to engine optimization is possible through an effective Design of Experiment (DoE). Various steps were devised like setting measurable target quantity & customer demands, parameter evaluation & screening, fractional factorial - orthogonal array design, experimentation, evolving objective/merit function, analysis, determination of optimum combinations and success run for validation. A naturally aspirated DI diesel engine is optimized using DoE for optimum performance and minimum emissions.

Today's automotive Air Intake Systems are developed to deliver maximum filtration efficiency, maximum dust holding capacity and maximum service interval range based on engine performance and reliability requirements. It must also meet requirements of packaging, higher flow rates, lower pressure drop, lower noise, better fuel economy, increased vehicle speed/acceleration, high temperature compatibility, corrosion resistance, easy serviceability and cost effectiveness. It requires a well-behaved uniform flow with minimum temperature rise and pressure drop across the system. The air intake system should be installed such that no water ingress or water traces are found during the water wading test. These challenging requirements cannot be met effectively without a systems approach. The Air Intake System development process starts with selection of design methodology and evolution of checklists for System Design Specifications (SDS) and definition of targets.

Application of Diesel Particulate Filter (DPF) will become necessary for trapping diesel particulate matter especially with stringent Emission Legislation of Euro IV and beyond. While developing a DPF, conflicting requirements like low-pressure drop, high thermal durability, high compressive strength, high trapping efficiency and practical regeneration needs to be considered. This paper focuses on the development and optimization of cost effective ceramic based DPFs for a diesel utility vehicle. The effect of DPF diameter, length, cell density and wall thickness on the pressure drop in fresh as well as soot laden conditions are evaluated, based on which the final size of DPF is determined. Special attention to substrate making, coating, canning, temperature and pressure feedback is given. Strategies for DPF regeneration like catalyzed and additive regeneration are evaluated.

More powerful and faster vehicles have increased the load on the conventional brake system, which lead to lower brake system life particularly that of brake liners. This is not only due to higher braking speed but also due to the frequent brake applications especially in city driving and downhill conditions with heavy loads. In order to deal with excessive heat released, which results from continuous braking during repetitive braking operation, it is essential that there must be some system to share the load of service brakes. This is achieved by use of auxiliary brakes like exhaust brakes, which shares the total braking force leading to better vehicle safety. This paper reviews the requirements, design considerations and design verification of exhaust brake developed for light commercial diesel vehicle. Electrical circuit, vacuum circuits and fuel cut-off system required for exhaust brake application are designed. Accelerator and brake controlled exhaust brake system are evaluated.