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The nonroad Final Tier 4 US EPA emission standards require 88% reduction in NOx emission from the Interim Tier 4 standards. It is necessary to utilize aftertreatment technologies to achieve the required NOx reduction. The development of a fuel reformer, lean NOx trap (LNT) and optional selective catalytic reactor (SCR) on a John Deere 4045 nonroad engine is described in this paper. The paper discusses aftertreatment system performance, catalyst formulations and system controls of a fuel vaporizer, fuel reformer, LNT and SCR system designed to meet the nonroad Final Tier 4 emission standards. The 4045 John Deere engine was calibrated and integrated with the aftertreatment system. The system performance was characterized in an engine dynamometer performance test cell, durability test cell and on a vehicle. The catalyst performance was evaluated using aged catalysts and a detailed description of the LNT, DPF and SCR catalysts is provided.

Diesel exhaust aftertreatment systems are required for meeting Final Tier 4 emission regulations. This paper addresses an aftertreatment system designed to meet the Final Tier 4 emission standards for nonroad vehicle markets. The aftertreatment system consists of a fuel dosing system, mixing elements, fuel vaporizer, fuel reformer, lean NOx trap (LNT), diesel particulate filter (DPF), and an optional selective catalytic reduction (SCR) catalyst. Aftertreatment system performance, both with and without the SCR, was characterized in an engine dynamometer test cell, using a 4.5 liter, pre-production diesel engine. The engine out NOx nominally ranged between 1.6 and 2.0 g/kW-hr while all operating modes ranged between 1.2 and 2.8 g/kW-hr. The engine out particulate matter was calibrated to approximately 0.1 g/kW-hr for various power ratings. Three engine power ratings of 104 kW, 85 kW and 78 kW were evaluated.