How to Improve Transient Engine Performance of HD Hydrogen Engines while Maintaining Lowest NOx Emissions

Authors

Dr.-Ing. L. Virnich, Dipl.-Ing. B. Lindemann, Dr.-Ing. M. Müther, Dr.-Ing. J. Schaub, Dr.-Ing. V. Huth, Dr.-Ing. J. Geiger, FEV Europe GmbH, Aachen:

Year

2021

Print Info

Production/Publication ÖVK

Summary

Increasingly stringent CO2 emission regulations demand a reorientation of powertrain concepts in the heavy-duty transport sector. By 2025, CO₂ emissions must be reduced by 15 % and down to 30 % by 2030 compared to the 2019 baseline. Besides increasing the efficiency of existing diesel engines, possible alternatives are the use of low-carbon (e.g. methane) or even zero-carbon fuels (e.g. hydrogen) and the partial or complete electrification of the powertrain. Hydrogen offers the possibility to be used either as a fuel for internal combustion engines or for fuel cells. Fuel cells in combination with battery electric drives offer the greatest benefit for applications with highly transient driving cycles, e.g. city buses or urban transport. However, if high constant power and less transient vehicle operation is required, an internal combustion engine fueled with hydrogen represents a cost-effective approach to realize zero CO₂ emission long haul transport. To convert a conventional diesel heavy duty engine to hydrogen operation, the combustion and turbocharging systems, the fuel injection and ignition systems as well as the controls software and the exhaust gas aftertreatment system must be redesigned. This paper focuses on the layout of the exhaust gas aftertreatment system and the required software structure to ensure lowest NO_x emissions even under highly transient engine operation conditions. First, a simulation model is calibrated using engine data derived from a two-stage turbo charged medium duty hydrogen engine. Then, transient load cycles are performed on engine test bench to evaluate the optimal layout of the after-treatment system. Different aftertreatment systems architectures as well as different operating strategies are evaluated with respect to their adaptation to the specific requirements of a hydrogen engine.

Number of pages

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