A “Hot and Cold” Experimental Analysis of Flow Distribution in a “Close Coupled” Catalytic Converter

2002 ◽  
Author(s):  
M. Cardone ◽  
V. Cioffi ◽  
R. Fiorenza ◽  
P. Gaudino ◽  
A. Senatore ◽  
...  
Keyword(s):  
Gas Flow ◽  
Oxygen Sensor ◽  
Catalytic Converter ◽  
Engine Performance ◽  
Flow Distribution ◽  
Integrated Modelling ◽  
Critical Parameters ◽  
Exhaust Manifold ◽  
Gas Treatment ◽  
Intake Flow

The tighter limits introduced by EURO3 and EURO4 regulations involve the adoption of exhaust configurations, in which the converter is located close to the manifold, in order to reduce light off time, and so to obtain lower emissions. This type of configuration introduces new problems relative to optimisation of the exhaust manifold geometry, which is no longer only linked to engine performance, but also has to guarantee the best possible operation of the exhaust gas treatment system. Critical parameters include lambda probe positioning and impingement of the gas flow, along with establishment of a flow field that corresponds to the catalytic converter intake area, as imposed by well known requests of reliability and functionality. The present work is aimed at integrated modelling and experimental optimisation of exhaust manifold geometry, with regard to oxygen sensor positioning and catalyst intake flow distribution, to find the best compromise between engine performance and exhaust emissions control.

Optimisation of Catalytic Converter Gas Flow Distribution by CFD Prediction

1993 ◽  
Author(s):  
Herman Weltens ◽  
Harald Bressler ◽  
Frank Terres ◽  
Hubert Neumaier ◽  
Detlev Rammoser
Keyword(s):  
Gas Flow ◽  
Catalytic Converter ◽  
Flow Distribution ◽  
Converter Gas

Numerical Analysis of Unsteady Exhaust Gas Flow and Its Application for Lambda Control Improvement

2003 ◽  
Vol 125 (2) ◽  
pp. 555-562 ◽  
Author(s):  
K. Yoshizawa ◽  
K. Mori ◽  
K. Arai ◽  
A. Iiyama
Keyword(s):  
Feedback Control ◽  
Gas Exchange ◽  
Calculation Method ◽  
Gas Flow ◽  
Oxygen Sensor ◽  
Gasoline Engine ◽  
Control Method ◽  
Exhaust Gas ◽  
Exhaust Manifold ◽  
Flow Calculation

A multidimensional computational fluid dynamics (CFD) tool has been applied to analyze the exhaust system of a gasoline engine. Since gas flow in the exhaust manifold is affected by exhaust pulsations, prediction methods based on steady flow are not able to predict gas flow precisely enough. Therefore, a new multidimensional calculation method, called pulsation flow calculation, has been developed. A one-dimensional gas exchange simulation and a three-dimensional exhaust gas flow calculation are combined to simulate gas flow pulsations caused by the gas exchange process. Predicted gas flow in the exhaust manifold agreed with the experimental data. With the aim of reducing emissions, the pulsation flow calculation method has been applied to improve lambda feedback control using an oxygen sensor. The factors governing sensor sensitivity to the exhaust gas from each cylinder were clarified. The possibility of selecting the oxygen sensor location in the exhaust manifold on the basis of calculations was proved. The effect of an exhaust manifold with equal-length cylinder runners on achieving uniform sensor sensitivities was made clear. In addition, a new lambda feedback control method for an exhaust manifold with different-length cylinder runners is proposed.

Simulation of an Automotive Catalytic Converter Internal Flow

2005 ◽  
Author(s):  
Bassem H. Ramadan
Keyword(s):  
Oxygen Sensor ◽  
Catalytic Converter ◽  
Internal Flow ◽  
The United States ◽  
Operating Conditions ◽  
Current Status ◽  
Reacting Flow ◽  
Exhaust Manifold ◽  
Catalytic Converters ◽  
Engine Exhaust

Catalytic converters have been used for a number of years in the United States to control automotive pollution. A catalytic converter needs to reach a certain temperature before the chemical reactions take place (light-off). Recently, the new regulations on emission standards have prompted a reconsideration of the design of automotive catalytic converters in order to reduce the light-off period of the catalyst. The catalytic converter light-off period is very Important since almost 80% of the emissions from vehicles occur within the first three minutes after cold start in the FTP-75 test. In order to meet these new regulations, current studies have suggested that the catalyst should be “close-coupled”; that is fitted close to the engine exhaust manifold. In order to design “close-coupled” converters, the designer may have to resort to truncated inlet and outlet cones, or distorted inlet pipes due to space limitations. Hence, it is very difficult to achieve good mixing of the exhaust gas, and a good flow distribution at the inlet cross section of the monolith. Based on such a current status in the study of the catalytic converter, the present work focuses on the time-dependent flow patterns, both in the exhaust manifold and the catalytic converter using Computational Fluid Dynamics (CFD). A three-dimensional grid model of an engine exhaust manifold and a close-coupled catalytic converter was developed and analyzed. The flow simulations were performed using KIVA-3 for non-reacting flow fields. These simulations were performed with transient boundary conditions applied at the inlet to the exhaust runners to simulate the opening and closing of exhaust valves. The CFD results were used to study flow uniformity under different operating conditions and to identify the best location for the oxygen sensor.

A Three-Dimensional Transient Numerical Study of a Close-Coupled Catalytic Converter Internal Flow

2004 ◽  
Author(s):  
Bassem H. Ramadan
Keyword(s):  
Oxygen Sensor ◽  
Numerical Study ◽  
Catalytic Converter ◽  
Three Dimensional ◽  
Internal Flow ◽  
Operating Conditions ◽  
Current Status ◽  
Reacting Flow ◽  
Exhaust Manifold ◽  
Engine Exhaust

Recently, the new regulations on emission standards have prompted a reconsideration of the design of automotive catalytic converters in order to reduce the light-off period of the catalyst. The catalytic converter light-off period is very Important since almost 80% of the emissions from vehicles occur within the first three minutes after cold start in the FTP-75 test. In order to meet these new regulations, current studies have suggested that the catalyst should be “close-coupled”; that is fitted close to the engine exhaust manifold. In order to design “close-coupled” converters, the designer may have to resort to truncated inlet and outlet cones, or distorted inlet pipes due to space limitations. Hence, it is very difficult to achieve good mixing of the exhaust gas, and a good flow distribution at the inlet cross section of the monolith. Based on such a current status in the study of the catalytic converter, the present work focuses on the time-dependent flow patterns, both in the exhaust manifold and the catalytic converter using Computational Fluid Dynamics (CFD). A three-dimensional grid model of an engine exhaust manifold and a close-coupled catalytic converter was developed and analyzed. The flow simulations were performed using KIVA-3 for non-reacting flow fields. These simulations were performed with transient boundary conditions applied at the inlet to the exhaust runners to simulate the opening and closing of exhaust valves. The CFD results were used to study flow uniformity under different operating conditions and to identify the best location of the oxygen sensor.

scholarly journals A model for burden distribution and gas flow distribution of bell-less top blast furnace with parallel hoppers

2016 ◽  
Vol 40 (23-24) ◽  
pp. 10254-10273 ◽  
Author(s):  
Lin Shi ◽  
Guangsheng Zhao ◽  
Mingxin Li ◽  
Xiang Ma
Keyword(s):  
Blast Furnace ◽  
Gas Flow ◽  
Flow Distribution ◽  
Burden Distribution

Analysis of Temperature and Gas Flow Distribution in Chamber with Wafer Batch

2018 ◽  
Vol 40 (17-18) ◽  
pp. 1498-1510
Author(s):  
Seung-Hwan Kang ◽  
Han Seo Ko
Keyword(s):  
Gas Flow ◽  
Flow Distribution

Investigation Techniques of In Situ AlMg/AlN Metal Matrix Composites via Reactive Gas Injection

2013 ◽  
Vol 837 ◽  
pp. 283-289 ◽  
Author(s):  
Raluca Maria Florea ◽  
Oana Bălţătescu ◽  
Aurelian Buzăianu ◽  
Ioan Carcea
Keyword(s):  
Metal Matrix ◽  
Gas Flow ◽  
Sem Analysis ◽  
Critical Parameters ◽  
Matrix Composites ◽  
Uniform Dispersion ◽  
Liquid Systems ◽  
Spontaneous Infiltration ◽  
Reactive Gas

In this paper characteristics of an AlMg/AlN composite produced in-situ and processed in a flowing N2 atmosphere is investigated. Some critical parameters such as the manufacturing process temperature, the percentage of the magnesium consumed, the flowing reactive gas flow and the time for completing the manufacturing are considered as variables for the parametric investigation. Moreover, the effect of different amount of Mg employed has been also investigated, since Mg acts as a catalyst at the surface both for the gas/liquid and solid/liquid systems. Traditional methods were used for the basic characterization of the composite. The microstructure of the composite was investigated by optical and scanning electron microscopy (OM, SEM). SEM analysis was performed in order to observe the microstructural evolution as a function of the Mg content and to identify some reasons of the presence of porosity or any irregularities within the metal matrix. The evolution of mechanical properties, in terms of microhardness, at different percentage of Mg were monitored. By EDS technique the distribution of the elements was obtained. Furthermore, employing an optimization process, uniform dispersion of the strengthening (AlN) particles in the metal matrix with homogeneous properties along the composite material is obtained. Based on the aforementioned statements, it can be concluded that the reactions between Al, Mg and the N2 atmosphere induce spontaneous infiltration in the metal matrix. The complete mix of properties and experimentally assessed parameters can be used for industrial purpose manufacturing design and development.

scholarly journals Modeling of the Transport and Exchange of a Gas Species in Lungs With an Asymmetric Branching Pattern. Application to Nitric Oxide

2020 ◽  
Vol 11 ◽  
Author(s):  
Alexandra Buess ◽  
Alain Van Muylem ◽  
Antoine Nonclercq ◽  
Benoit Haut
Keyword(s):  
Nitric Oxide ◽  
Gas Flow ◽  
Flow Distribution ◽  
Distal Region ◽  
Tracheobronchial Tree ◽  
Chronic Obstructive ◽  
Branching Pattern ◽  
Gaseous Species ◽  
Obstructive Pulmonary Disease ◽  
Pattern Application

Over the years, various studies have been dedicated to the mathematical modeling of gas transport and exchange in the lungs. Indeed, the access to the distal region of the lungs with direct measurements is limited and, therefore, models are valuable tools to interpret clinical data and to give more insights into the phenomena taking place in the deepest part of the lungs. In this work, a new computational model of the transport and exchange of a gas species in the human lungs is proposed. It includes (i) a method to generate a lung geometry characterized by an asymmetric branching pattern, based on the values of several parameters that have to be given by the model user, and a method to possibly alter this geometry to mimic lung diseases, (ii) the calculation of the gas flow distribution in this geometry during inspiration or expiration (taking into account the increased resistance to the flow in airways where the flow is non-established), (iii) the evaluation of the exchange fluxes of the gaseous species of interest between the tissues composing the lungs and the lumen, and (iv) the computation of the concentration profile of the exchanged species in the lumen of the tracheobronchial tree. Even if the model is developed in a general framework, a particular attention is given to nitric oxide, as it is not only a gas species of clinical interest, but also a gas species that is both produced in the walls of the airways and consumed within the alveolar region of the lungs. First, the model is presented. Then, several features of the model, applied to lung geometry, gas flow and NO exchange and transport, are discussed, compared to existing works and notably used to give new insights into experimental data available in the literature, regarding diseases, such as asthma, cystic fibrosis, and chronic obstructive pulmonary disease.

scholarly journals Two Efficient Methods for Gas Distributive Network Calculation

2018 ◽  
Author(s):  
Dejan Brkić
Keyword(s):  
Pressure Drop ◽  
Thermodynamic Properties ◽  
Gas Flow ◽  
Flow Distribution ◽  
Gas Pipeline ◽  
Gas Flow Rate ◽  
Closed Loops ◽  
Loop Method ◽  
Hardy Cross ◽  
Flow Through

Today, two very efficient methods for calculation of flow distribution per branches of a looped gas pipeline are available. Most common is improved Hardy Cross method, while the second one is so-called unified node-loop method. For gas pipeline, gas flow rate through a pipe can be determined using Colebrook equation modified by AGA (American Gas Association) for calculation of friction factor accompanied with Darcy-Weisbach equation for pressure drop and second approach is using Renouard equation adopted for gas pipeline calculation. For the development of Renouard equation for gas pipelines some additional thermodynamic properties are involved in comparisons with Colebrook and Darcy-Weisbach model. These differences will be explained. Both equations, the Colebrook’s (accompanied with Darcy-Weisbach scheme) and Renouard’s will be used for calculation of flow through the pipes of one gas pipeline with eight closed loops which are formed by pipes. Consequently four different cases will be examined because the network is calculated using improved Hardy Cross method and unified node-loop method. Some remarks on optimization in this area of engineering also will be mentioned.

Sign in / Sign up

Export Citation Format

Share Document