Measurement of Exhaust Gas Temperatures: Theoretical and Experimental Analysis

2002 ◽  
Author(s):  
Nicolo` Cavina
Keyword(s):  
Experimental Analysis ◽  
Measurement Errors ◽  
Control Strategies ◽  
Catalytic Converter ◽  
Model Identification ◽  
Operating Conditions ◽  
Exhaust Gas ◽  
Exhaust Manifold ◽  
Si Engine ◽  
Polluting Emissions

The optimal management of the three-way catalytic converter is today widely recognized as one of the means to further reduce Spark Ignition (SI) engine polluting emissions, and therefore to respect future emission regulations. Its conversion efficiency is strictly dependent on the operating temperature, and most engine control strategies are today either based on mathematical models that determine such temperature as a function of the engine operating conditions, or on its direct measurement. It is therefore useful to investigate the errors that could arise when measuring exhaust gas temperatures, either during model identification tests or on board the vehicle. The paper presents a theoretical and experimental analysis on the phenomena that could lead to relevant measurement errors in such applications. A physical model of the heat transfer phenomena that take place in the exhaust manifold has been developed to estimate both the exhaust gas temperatures and the error that would arise while measuring them with typical sensors such as thermocouples. The exhaust manifold of a 1.2 liter SI engine was equipped with different types of sensors for the model identification and validation phases.

scholarly journals Improving the Uncertainty of Exhaust Gas Temperature Measurements in Internal Combustion Engines

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Nick Papaioannou ◽  
Felix Leach ◽  
Martin Davy
Keyword(s):  
Measurement Errors ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Operating Conditions ◽  
Exhaust Gas ◽  
Combustion Engines ◽  
Gas Temperature ◽  
Crank Angle ◽  
Reconstructed Temperature ◽  
Exhaust Gas Temperature

Abstract Accurate measurement of exhaust gas temperature (EGT) in internal combustion engines (ICEs) is a challenging task. The most common, and also the most practical, method of measurement is to insert a physical probe, for example, a thermocouple or platinum resistance thermometer, directly into the exhaust flow. Historically, consideration of the measurement errors induced by this arrangement has focused on the effects of radiation and the loss of temporal resolution naturally associated with a probe of finite thermal inertia operating within a pulsating flow with a time-varying heat input. However, a recent numerical and experimental study has shown that conduction errors may also have a significant effect on the measured EGT, with errors approaching ∼80 K depending on engine operating conditions. In this work, the authors introduce a new temperature compensation method that can correct for the combined radiation, conduction, and dynamic response errors introduced during the measurement and thereby reconstruct the “true” crank-angle resolved EGT to an estimated accuracy of ±1.5%. The significance of this result is demonstrated by consideration of a first law energy balance on an engine. It is shown that the exhaust gas enthalpy term is underestimated by 15–18% when calculated using conventional time-averaged data as opposed to using the mass-average exhaust enthalpy that is obtained by combining the reconstructed temperature data with crank angle-resolved exhaust flow rates predicted by a well-validated one-dimensional (1D) simulation.

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.

Performance improvement of turbocharged SI engine by post-oxidation enhancement in exhaust gas in-homogeneity

2020 ◽  
pp. 146808742096087 ◽  
Author(s):  
Madan Kumar ◽  
Salaar Moeeni ◽  
Tatsuya Kuboyama ◽  
Yasuo Moriyoshi
Keyword(s):  
Performance Improvement ◽  
Experimental Validation ◽  
Engine Performance ◽  
Simulation Models ◽  
Experimental Results ◽  
Exhaust Gas ◽  
Exhaust Manifold ◽  
Si Engine ◽  
Exhaust Port ◽  
Design And Implementation

In this research, the improvement of mixing and pulsation in exhaust manifold with a design and implementation of bypass adapter at exhaust port were deeply investigated. This in-turn can improve the post-oxidation phenomena and hence emissions and engine performance could be enhanced. This research investigation includes 1-D, 3-D simulations and experimental validation on a 4-cylinder turbocharged spark ignition (SI) engine. Firstly, the 1-D and 3-D simulation models were developed and calibrated with the experimental results. Then, the simulations were used for the detailed investigation of mixing and pulsation in exhaust manifold with and without bypass adapter. Thereafter, experimental test for the post-oxidation were conducted with and without consideration of the bypass adapter and results were compared. From the simulation and experimental results, it was proven that by using bypass adapter at the exhaust port, the mixing of exhaust gas species was observed to be significantly improved to some extent. Also, the unbalance between exhaust port and turbocharger upstream gas species were reduced. This also reduced the exhaust gas pulsation. By the improvement of mixing between scavenged O2 and unburned gas species, the post-oxidation reaction was also noted to have improved and consequently the emissions and turbo-speed were found to be better that led to an improved IMEP and thermal efficiency of the engine.

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