Future HD Diesel and Hydrogen-Fueled Concepts: Emissions Challenges and System Solutions

Abstract

<div class="section abstract"><div class="htmlview paragraph">Future heavy-duty (HD) concepts should fulfill very tight tail-pipe NO<sub>x</sub> emissions and simultaneously fulfill the fuel efficiency targets. In current HD Euro VII discussions, real working cycles become key to ensure emission conformity. For instance, cold start and cold ambient conditions during testing with low load profiles starting from 0% payload, require external heating measures. Knowing the trade-off between fuel consumption and tail-pipe NO<sub>x</sub> emissions a holistic engine and EAT system optimization with innovative thermal management is required.</div><div class="htmlview paragraph">Towards a carbon neutral mobility, Hydrogen combustion engines are one of the key solutions. Advanced combustion system development enables maximal usage of lean burning as the major advantage of the Hydrogen fuel for efficiency improvement and NO<sub>x</sub> reduction. Considering future NO<sub>x</sub> regulations in real-world working cycles, an efficient exhaust after-treatment (EAT) system which is well optimized to the air-path and the Hydrogen combustion characteristics is required.</div><div class="htmlview paragraph">In this paper, a systematic investigation is carried out by means of the model-based holistic approach. The target is an optimization of both engine and EAT layout, including advanced thermal management for future HD concepts. Both Diesel and Hydrogen HD concepts are investigated.</div><div class="htmlview paragraph">The model-based emission conception is based on both the conventional WHTC cycle as well as on selected real field cycles. Close-coupled dual-stage SCR with twin dosing is considered with multiple system layouts in order to minimize the Diesel engine fuel penalty during the heat up phases. A comparison between the emission behavior and after-treatment systems of Diesel and Hydrogen engines is performed.</div><div class="htmlview paragraph">In addition, external EAT heating such as electric heated catalyst is investigated for Diesel applications and the potentials regarding CO<sub>2</sub> emissions compared to conventional engine-based thermal management measures are shown.</div><div class="htmlview paragraph">The optimized system layout for both Diesel and Hydrogen HD concepts are compared, especially for the EAT technology and layout. As outlook, future potentials and optimization possibilities for combustion systems and future emission reduction technologies are described.</div></div>