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Technical Paper

The Effect of a Diesel Oxidation Catalyst and a Catalyzed Particulate Filter on Particle Size Distribution from a Heavy Duty Diesel Engine

2006-04-03
2006-01-0877
The effect of a Johnson Matthey catalyzed continuously regenerating technology™ (CCRT®) filter on the particle size distribution in the raw exhaust from a 2002 Cummins ISM-2002 heavy duty diesel engine (HDDE) is reported at four loads. A CCRT® (henceforth called DOC-CPF) has a diesel oxidation catalyst (DOC) upstream (UP) of a catalyzed particulate filter (CPF). The particle size data were taken at three locations of UP DOC, downstream (DN) DOC and DN CPF in the raw exhaust in order to study the individual effect of the DOC and the CPF of the DOC-CPF on the particle size distribution. The four loads of 20, 40, 60 and 75% loads at rated speed were chosen for this study. Emissions measurements were made in the raw exhaust chosen to study the effect of nitrogen dioxide and temperature on particulate matter (PM) oxidation in the CPF at different engine conditions, exhaust and carbonaceous particulate matter (CPM) flow rates.
Technical Paper

The Effect of a Diesel Oxidation Catalyst and a Catalyzed Particulate Filter on the Emissions from a Heavy Duty Diesel Engine

2006-04-03
2006-01-0875
The objective of this research was to study the effects of a CCRT®, henceforth called Diesel Oxidation Catalyst - Catalyzed Particulate Filter (DOC-CPF) system on particulate and gaseous emissions from a heavy-duty diesel engine (HDDE) operated at Modes 11 and 9 of the old Environmental Protection Agency (EPA) 13-mode test cycle Emissions characterized included: total particulate matter (TPM) and components of carbonaceous solids (SOL), soluble organic fraction (SOF) and sulfates (SO4); vapor phase organics (XOC); gaseous emissions of total hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOx), nitric oxide (NO) and nitrogen dioxide (NO2), oxygen (O2) and carbon dioxide (CO2); and particle size distributions at normal dilution ratio (NDR) and higher dilution ratio (HDR). Significant reductions were observed for TPM and SOL (>90%), SOF (>80%) and XOC (>70%) across the DOC-CPF at both modes.
Technical Paper

An Experimental and Computational Study of the Pressure Drop and Regeneration Characteristics of a Diesel Oxidation Catalyst and a Particulate Filter

2006-04-03
2006-01-0266
An experimental and computational study was performed to evaluate the performance of the CRT™ technology with an off-highway engine with a cooled low pressure loop EGR system. The MTU-Filter 1D DPF code predicts the particulate mass evolution (deposition and oxidation) in a diesel particulate filter (DPF) during simultaneous loading and during thermal and NO2-assisted regeneration conditions. It also predicts the pressure drop across the DPF, the flow and temperature fields, the solid filtration efficiency and the particle number distribution downstream of the DPF. A DOC model was also used to predict the NO2 upstream of the DPF. The DPF model was calibrated to experimental data at temperatures from 230°C to 550°C, and volumetric flow rates from 9 to 39 actual m3/min.
Technical Paper

An Advanced 1D 2-Layer Catalyzed Diesel Particulate Filter Model to Simulate: Filtration by the Wall and Particulate Cake, Oxidation in the Wall and Particulate Cake by NO2 and O2, and Regeneration by Heat Addition

2006-04-03
2006-01-0467
A numerical model to simulate the filtration and regeneration performance of catalyzed diesel particulate filters (CPFs) was developed at Michigan Technological University (MTU). The mathematical formulation of the model and some results are described. The model is a single channel (inlet and outlet) representation of the flow while the thermal and catalytic regeneration framework is based on a 2-layer approach. The 2-layer model can simulate particulate matter (PM) oxidation by thermal and ‘catalytic’ means of oxidation with O2. Several improvements were made to this basic model and are described in this paper. A model to simulate PM oxidation by NO2/Temperature entering the particulate filter and oxidizing the PM in the two layers of the PM cake was developed. This model can be used to simulate the performance of filters with catalyst washcoats and uncatalyzed filters placed downstream of diesel oxidation catalysts (DOCs), as in the continuously regenerating traps, CRT's®.
Technical Paper

An Experimental and Modeling Study of a Diesel Oxidation Catalyst and a Catalyzed Diesel Particulate Filter Using a 1-D 2-Layer Model

2006-04-03
2006-01-0466
Modeling of diesel exhaust after-treatment devices is a valuable tool in the development and performance evaluation of these devices in a cost effective manner. Results from steady state loading experiments on a catalyzed particulate filter (CPF) in a Johnson Matthey CCRT®, performed with and without the upstream diesel oxidation catalyst (DOC) are described in this paper. The experiments were performed at 20, 40, 60 and 75% of full load (1120 Nm) at rated speed (2100 rpm) on a Cummins ISM 2002 heavy duty diesel engine. The data obtained were used to calibrate one dimensional (1-D) DOC and CPF models developed at Michigan Technological University (MTU). The 1-D 2-layer single channel CPF model helped evaluate the filtration and passive oxidation performance of the CPF. DOC modeling results of the pressure drop and gaseous emission oxidation performance using a previously developed model are also presented.
Technical Paper

A Study of the Filtration and Oxidation Characteristics of a Diesel Oxidation Catalyst and a Catalyzed Particulate Filter

2007-04-16
2007-01-1123
An experimental and modeling study was conducted to study the passive regeneration of a catalyzed particulate filter (CPF) by the oxidation of particulate matter (PM) via thermal and Nitrogen dioxide/temperature-assisted means. Emissions data in the exhaust of a John Deere 6.8 liter, turbocharged and after-cooled engine with a low-pressure loop EGR and a diesel oxidation catalyst (DOC) - catalyzed particulate filter (CPF) in the exhaust system was measured and used for this study. A series of experiments was conducted to evaluate the performance of the DOC, CPF and DOC+CPF configurations at various engine speeds and loads.
Technical Paper

An Experimental and Numerical Study of the Performance Characteristics of the Diesel Oxidation Catalyst in a Continuously Regenerating Particulate Filter

2003-10-27
2003-01-3176
A one-dimensional model simulating the oxidation of CO, HC, and NO was developed to predict the gaseous emissions downstream of a diesel oxidation catalyst (DOC). The model is based on the conservation of mass, species, and energy inside the DOC and draws on past research literature. Steady-state experiments covering a wide range of operating conditions (exhaust temperatures, flow rates and gaseous emissions) were performed, and the data were used to calibrate and validate the model. NO conversion efficiencies of 50% or higher were obtained at temperatures between 300°C and 350°C. CO conversion efficiencies of 85% or higher and HC conversion efficiencies of 75% or higher were found at every steady state condition above 200°C. The model agrees well with the experimental results at temperatures from 200°C to 500°C, and volumetric flow rates from 8 to 42 actual m3/min.
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