Experimental determination and modelling of the diesel oxidation catalysts ageing effects

Abstract

After-treatment systems are necessary to respect the pollutant emissions thresholds specified by regulations. However, due to system ageing, the efficiency of the after-treatment system may decrease and affect the vehicle emissions during real driving conditions. To address this issue, the model presented in this article is based on the on-engine tests performed to a set of diesel oxidation catalysts with different ageing levels, through which the ageing process is characterized. Then, the model is able to simulate the light-off temperature and slip increase due to ageing, and it is applied to a Worldwide Harmonized Light Vehicles Test Cycle for a new and a thermally aged catalysts.

Variable Valve Actuation for Efficient Exhaust Thermal Management in an Off-Road Diesel Engine

“…1. A diesel oxidation catalyst (DOC) reduces hydrocarbon (HC), carbon monoxide (CO), and soluble organic fraction through catalytic reactions with oxygen [7,8]. Subsequently, a diesel particulate filter (DPF) captures PM via filtration.…”

“…Although modern diesel engines primarily emit NO x in the form of NO [11], this is converted to NO 2 in the DOC and SCR [11]. The conversion of NO to NO 2 impacts both DPF passive regeneration [12] and NO x reduction in the SCR [8]. Nevertheless, the adoption of EATS introduces inherent challenges, including higher vehicle costs for consumers, increased backpressure in the exhaust system, additional maintenance requirements and the periodic need to replenish the urea reservoir [13].…”

“…EGT is one of crucial factors, along with exhaust mass flow rate and exhaust gas composition, to influence the performance of DOC and SCR Modern integrated exhaust aftertreatment system for diesel engines. [8,22]. High EGT accelerates catalytic reactions, providing high EATS conversion efficiency.…”

Predicting instantaneous engine-out NOx emissions in a real-driving vehicle data scenario

“…8,9 Nevertheless, the engine, the sensors and actuators, as well as the after-treatment systems, are subject to wear and aging which might lead to a drop in emissions performance. [10][11][12] In this regard, exhaust emissions models participate into optimizing control strategies and improving diagnostics capabilities. [13][14][15][16] Among the regulated pollutants, nitrogen oxides (NO x ) emission has received a particular attention from the industry and the research community due to its harmful potential on health.…”

“…8,9 Nevertheless, the engine, the sensors and actuators, as well as the after-treatment systems, are subject to wear and aging which might lead to a drop in emissions performance. 10–12 In this regard, exhaust emissions models participate into optimizing control strategies and improving diagnostics capabilities. 13–16…”