The autothermal reforming of diesel fuel is a catalytic process that runs at temperatures of 700 degrees C-900 degrees C. Long-chain hydrocarbon molecules react with steam and O-2, yielding a product gas that mainly consists of CO, CO2, CH4 and H-2. H-2 is essential for the operation of fuel cell systems. The Forschungszentrum Mich has been engaged in the cooperative development of technical apparatus for this reaction to be applied in fuel cell systems over the past 15 years, together with many other research groups worldwide, and this paper deals with reactor ATR 14, which is considered the preliminary end-product of Julich's research and development in this field. This paper briefly summarizes Julich's earlier reactor generations and then describes the most recent improvements embodied in the ATR 14. Additionally, the experimental evaluation of the ATR 14 is presented, which demonstrates that it can be operated over a broad load range and with almost complete carbon conversion. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.