Design and Performance Optimization of Off-highway Diesel Engine with Mechanical Fuel Injection Equipment for TIER-IV Emission Norms

Abstract

The two cylinder diesel engines are most demanding product in Indian market for power genset and tractor applications. But major task faced by engine manufacturers all over the world is to upgrade running engine designs with minimum and cost-effective modifications to meet the next level of emission norms. This saves the precious lead time and investments. In addition uncomplicated design has to be sustained as far as possible while improving emissions. Further the basic desires of the end user in off-road market are good response, transient performance, better low end torque, best fuel efficiency and smooth operation of the engine besides best in class reliability. Additional requirements needed to sustain the market with higher power to weight ratio and increased life of the engine. Henceforth turbocharging applications for off-road diesel engines are promising solution for enhancing rated power, low speed torque, transient performance, optimized fuel efficiency and engine downsizing. A trade-off is required to match some incompatible design issues like overall dimensions, cost, emissions control and performance in order to sustain the existing design. Future diesel engine emission standards will restrict vehicle emissions, particularly nitrogen oxides. In the present work, performance improvement for 1.7L, 2 cylinder in-line naturally aspirated diesel engine with mechanical fuel injection pump for off-road application is developed to contain all needs of the market. Design up-gradation of this engine for Tier IV is made with minimal design changes by optimal combinations of fuel injection equipment. This includes proper optimization of performance with improvements in nozzle geometry, change in injector end pressure. But due to the increased fuel flow rates for improving the engine performance as well as emission reduction, there is also a requirement for increased air flow. Henceforth in this study air flow rate is simulated and discussed for selection of turbocharger and intercooler. Further elaborate design and analysis study is also done on cooled exhaust gas recirculation system for exhaust gas cooling efficiency, Diesel Oxidation catalyst, Selective Catalytic Reduction /Lean NOx Trap substrate selection for reduced pressure drop and maximum retention time for exhaust gas to achieve Tier IV norms in turbocharged intercooled two cylinder engine.