Optimised Air Management System for Heavy Duty Hydrogen Engines

<div class="section abstract"><div class="htmlview paragraph">Many Indian cities are amongst the most polluted cities in the world. Transport sector is identified as one of the major contributors to air pollution. Following the global trend, Government of India is also promoting near zero emission fuels with zero CO2 emissions as a way forward to solve the emission problems. With its policies like Green Hydrogen Mission, government of India plans to accelerate the adoption of Hydrogen as a fuel in the country. These initiatives have created a breakthrough in development of Hydrogen ICEs by the Indian OEM’s. Hydrogen ICE have only NOx emissions as the most prominent engine out emissions. NOx emission in Hydrogen engines is very sensitive to operating lambda, where in, after a certain threshold lambda the emissions rise significantly. Therefore, the air management system plays a very important role in the hydrogen engine performance &amp; NOx emissions. This study evaluates various air management system options for a heavy-duty Hydrogen engine. Initially, a single stage variable geometry turbocharger (VGT) was assessed with focus on good low-end torque capabilities. The rated power output with the single stage turbocharger can be improved by supplying cooled HP EGR, by shifting the turbocharger operating points towards higher efficiency and lower turbocharger speed improving speed margin. The single stage TC configuration is then evaluated against a 2-stage VGT turbo charger configuration, which achieved higher lambda levels, thereby improving low-end torque, and reducing NOx emissions. The 2-stage turbo charging achieved higher brake efficiency and improved altitude capability. This study has been performed using 1D simulation based on validated engine model from FEV database. The mentioned TC systems have been matched for the engine requirements, and engine mappings created. The mappings are then used to assess the cyclic NOx emissions for the different TC configurations over the WHTC emissions cycle to assess the improvement in the emissions and requirement of overall De-NOx system requirements.</div></div>