Thermal-Mechanical Durability of DOC and DPF After-treatment System for Light Heavy Pickup Truck Application

摘要

The US Environmental Protection Agency (EPA)'s heavy-duty diesel emission standard was tightened beginning from 2007 with the introduction of ultra-low-sulfur diesel fuel. Most heavy-duty diesel applications were required to equip Particulate Matter (PM) after-treatment systems to meet the new tighter, emission standard. Systems utilizing Diesel Oxidation Catalyst (DOC) and Catalyzed-Diesel Particulate Filter (DPF) are a mainstream of modern diesel PM after-treatment systems. To ensure appropriate performance of the system, periodic cleaning of the PM trapped in DPF by its oxidation (a process called 'regeneration') is necessary. As a result, of this regeneration, DOC's and DPF's can be exposed to hundreds of thermal cycles during their lifetime. Therefore, to understand the thermo-mechanical performance of the DOC and DPF is an essential issue to evaluate the durability of the system. This paper reports empirical data obtained from dynamometers, vehicles, and simulators as well as numerical simulation stress analysis results which were conducted for the development of DOC and DPF after-treatment systems used in General Motors Corporation 2007 light heavy-duty diesel pickup truck with the 6.6-liter Duramax diesel engine.