Assessment by means of gas dynamic modelling of a pre-turbo diesel particulate filter configuration in a turbocharged HSDI diesel engine under full-load transient operation

Abstract

to deal with the characteristic highly pulsating flow upstream of the turbine. Several levels of DPF soot loading has been considered to properly represent the most exigent conditions in terms of performance requirements. As a result, the main physical phenomena controlling the engine and DPF response and interaction have been identified. In concrete, to place the DPF upstream the turbine will lead to an number of important advantages due to the continuous regeneration mode at which DPF will operate, the lower pressure drop in the DPF and the thermal energy storage in the DPF very useful to mitigate 'turbocharger lag' during engines transient operation. These three effects have been evidenced with calculations performed with the validated model and the results have been properly analyzed and discussed through the paper.

Analysis of heavy-duty turbocharged diesel engine response under cold transient operation with a pre-turbo aftertreatment exhaust manifold configuration

“…Diesel engine with pre-turbo aftertreatment architecture. The reason is that such a characteristic allows the substrate to heat the gas exhaust flowing through it leading to remove the turbocharger lag [15][17]. However, thermal inertia also becomes the parameter controlling the response of the engine in a tip-in process performed during the engine warmup or from low wall temperature in the exhaust line.…”

“…Immediate advantages of these architectures are identified in terms of higher thermal level favouring passive regeneration occurrences in the DPF and enhancing the DOC light-off and conversion efficiency [14]. This kind of architecture reduces the pressure drop across the DPF because of the flow conditions upstream of the turbine [15].…”

“…As a consequence, the turbocharger speed slight varies during this phase. This fact involves a decrease in turbocharger lag during the acceleration after zero-load periods [15]. By contrast, under cold exhaust wall conditions, the thermal inertia gives rise to a slow increase in energy available for the turbine during the load phase.…”

Application of the two-step Lax and Wendroff FCT and the CE-SE method to flow transport in wall-flow monoliths

“…The development of these systems is conditioned by their effects on engine performance and gas flow path [1,2], but also by the competitive nature of the market, which demands the manufacturers to provide solutions regarding engine architecture and technology with high timing restrictions.…”

“…In the case of the wall-flow DPF, the models are usually simplified to quasi-steady incompressible flow because of the traditional placement of this element at the engine tailpipe [17]. However, the improvement of the wall-flow DPF modelling regarding aspects such as the prediction of the acoustic response [20], the heat transfer [9] or the evaluation of pre-turbo aftertreatment systems [1,2] is leading to the consideration of unsteady and compressible flow effect [16,20].…”