Preliminary Thermal Analyses on Diesel Converter Overheating

2004 ◽  
Author(s):  
Jun Zuo ◽  
Meiping Wang ◽  
Graham T. Reader ◽  
Ming Zheng
Keyword(s):  
Oxygen Concentration ◽  
Active Flow Control ◽  
Thermal Analyses ◽  
Gas Temperature ◽  
Engine Exhaust ◽  
Transient Model ◽  
Exhaust Temperature ◽  
Combustible Gas ◽  
Soot Loading ◽  
Reduce Emissions

The use of oxidation catalytic converters (OCC) in Diesel engines has proved to be an effective method to reduce emissions of total hydrocarbons (THC), carbon monoxide (CO), and the soluble organic fractions (SOF) of particulate matter (PM). However, the exothermal reaction effected by the oxidation of THC, CO, and especially the soot accumulated in the converters impose a risk of catalytic flow bed overheating that subsequently results in catalyst failure and may cause safety concerns. This paper presents a one-dimensional transient model that uses an energy balance method to analyze the overheating scenario when considering combustible gas reaction, clogged soot burning, and active flow control for a number of Diesel aftertreatment devices. The monolith temperature profiles were simulated by varying the exhaust gas temperature, oxygen concentration, and flow rate. Simulation results indicated that the potential of overheating elevates with increases in combustible gas concentration, soot loading, oxygen concentration, and engine exhaust temperature. The impacts of active control, such as flow reversal control, on converter overheating have also been investigated therein.

The Effect of Engine Exhaust Temperature Modulations on the Performance of Automotive Catalytic Converters

2006 ◽  
Author(s):  
Tariq Shamim
Keyword(s):  
Single Channel ◽  
Catalytic Converter ◽  
Space Velocity ◽  
Operating Conditions ◽  
Gas Temperature ◽  
Engine Exhaust ◽  
Exhaust Temperature ◽  
Automotive Catalytic Converters ◽  
Exhaust Gas Temperature ◽  
Harmful Effects

This paper presents a computational investigation of the effect of exhaust temperature modulations on an automotive catalytic converter. The objective is to develop a better fundamental understanding of the converter’s performance under transient driving conditions. Such an understanding will be beneficial in devising improved emission control methodologies. The study employs a single-channel based, one-dimensional, non-adiabatic model. The transient conditions are imposed by varying the exhaust gas temperature sinusoidally. The results show that temperature modulations cause a significant departure in the catalyst behavior from its steady behavior, and modulations have both favorable and harmful effects on pollutant conversion. The operating conditions and the modulating gas composition and flow rates (space velocity) have substantial influence on catalyst behavior.

Prediction of Ship Main Engine Exhaust Gas Temperature Using AR Model

2014 ◽  
Vol 697 ◽  
pp. 244-248
Author(s):  
Yue Wen Zhang ◽  
Yong Jiu Zou ◽  
Zhu Feng Liu ◽  
Peng Zhang
Keyword(s):  
Power Plant ◽  
Thermal Performance ◽  
Ar Model ◽  
Performance Parameters ◽  
Gas Temperature ◽  
Engine Exhaust ◽  
Exhaust Temperature ◽  
Actual Application ◽  
Change Trend ◽  
Predicted Values

In order to forecast the malfunctional state of main power plant on ships through predicting the trend of unsteadily changed thermal performance parameters in main power plant system, this paper established AR model for thermal performance parameters using time series analysis method, by which to predict the change trend analysis of thermal performance parameters, and comparing the predicted values and the measured values. The actual application case of predicting a main engine’s exhaust temperature has been validated by using of the AR model, and results showed that: AR model can accurately predict the change trend of smoke temperature, and the prediction precision is higher, the average relative error was 0.25%.

The Effect of Engine Exhaust Temperature Modulations on the Performance of Automotive Catalytic Converters

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Tariq Shamim
Keyword(s):  
Single Channel ◽  
Catalytic Converter ◽  
Space Velocity ◽  
Operating Conditions ◽  
Gas Temperature ◽  
Engine Exhaust ◽  
Exhaust Temperature ◽  
Automotive Catalytic Converters ◽  
Exhaust Gas Temperature ◽  
Harmful Effects

This paper presents a computational investigation of the effect of exhaust temperature modulations on an automotive catalytic converter. The objective is to develop a better fundamental understanding of the converter’s performance under transient driving conditions. Such an understanding will be beneficial in devising improved emission control methodologies. The study employs a single-channel based, one-dimensional, nonadiabatic model. The transient conditions are imposed by varying the exhaust gas temperature sinusoidally. The results show that temperature modulations cause a significant departure in the catalyst behavior from its steady behavior, and modulations have both favorable and harmful effects on pollutant conversion. The operating conditions and the modulating gas composition and flow rates (space velocity) have substantial influence on catalyst behavior.

The Design of Exhaust Gas Cooler for Diesel Particulate Bag Filter

2015 ◽  
Vol 737 ◽  
pp. 608-611
Author(s):  
Xiu Ye Wang ◽  
Guo Bin Li ◽  
Nan Xu
Keyword(s):  
Diesel Exhaust ◽  
Particulate Filter ◽  
Particulate Emissions ◽  
Bag Filter ◽  
Engine Exhaust ◽  
Particulate Emission ◽  
Filter System ◽  
Exhaust Temperature ◽  
Diesel Exhaust Particulate ◽  
Exhaust Particulate

Currently, the application of bag-filter technology in controlling diesel exhaust particulate emissions has been close to practical stage. As one of the key links in bag-filter technology, engine exhaust cooling can directly influence working safety of the entire exhaust particulate filter system. Thermodynamic calculations and experimental research of water-cooled chiller has provided a feasible basis for water cooler to be used in actual diesel exhaust particulate emission control system. The cooler can make engine exhaust temperature drop from 400 to 180 . Even when engine works in high-speed and high-load condition, inlet exhaust temperature of cooler can descend from 500 to 190 or so after cooling, which can still meet bag-filter system requirement of below 200 .

Impact of Oxygen Enriched Air on High Intensity Combustion and Emission

2015 ◽  
Author(s):  
Ahmed O. Said ◽  
Ahmed E. E. Khalil ◽  
Daniel Dalgo ◽  
Ashwani K. Gupta
Keyword(s):  
Oxygen Concentration ◽  
Reaction Zone ◽  
Combustion Efficiency ◽  
Oxygen Enrichment ◽  
Chemiluminescence Intensity ◽  
Exhaust Temperature ◽  
Lean Combustion ◽  
Unstable Combustion ◽  
The Impact ◽  
Co Emission

The influence of oxygen enriched air-methane flame under non-premixed and premixed fuel-lean combustion conditions is examined with focus on the emission of NO and CO, combustor exit temperature (Texit), and distribution of OH* chemiluminescence intensity. A cylindrical combustor was used at combustion intensity of 36MW/m3.atm and heat load of 6.25 kW. Results are also reported with normal air (21% oxygen). Oxygen enrichment provided stable combustion operation at lower equivalence ratios than normal air and also reduced CO emission. Increase in oxygen concentration from 21% to 25% and 30% increased the NO and decreased CO emissions at all equivalence ratios examined. Using 30% O2 enriched air in premixed case showed NO emissions of 11.4 ppm and 4.6 ppm at equivalence ratios of 0.5 and 0.4, respectively. Oxygen enrichment also reduced CO emission to 38 ppm at equivalence ratio of 0.5. Operating the combustor with normal air at these equivalence ratios resulted in unstable combustion. OH* Chemiluminescence revealed increased chemiluminescence intensity with the reaction zone to shift upstream at increased oxygen concentration. The exhaust temperature of the combustor increased with oxygen enrichment leading to lower CO concentration and increased combustion efficiency. The oxidizer injected at higher velocities mitigated the impact of reaction zone to move upstream that helped to reduce significantly both the NO and CO emission specifically under non-premixed combustion.

scholarly journals Late Fuel Post-Injection Influence on the Dynamics and Efficiency of Wall-Flow Particulate Filters Regeneration

2019 ◽  
Vol 9 (24) ◽  
pp. 5384 ◽  
Author(s):  
José Ramón Serrano ◽  
Pedro Piqueras ◽  
Joaquín de la Morena ◽  
Enrique José Sanchis
Keyword(s):  
Fuel Consumption ◽  
Particulate Filter ◽  
Exhaust Gas ◽  
Post Injection ◽  
Gas Temperature ◽  
Diesel Particulate ◽  
Particulate Filters ◽  
Exhaust Temperature ◽  
Injection Parameters ◽  
Wall Flow

Late fuel post-injections are the most usual strategy to reach high exhaust temperature for the active regeneration of diesel particulate filters. However, it is important to optimise these strategies in order to mitigate their negative effect on the engine fuel consumption. This work aims at understanding the influence of the post-injection parameters, such as its start of injection and its fuel quantity, on the duration of the regeneration event and the fuel consumption along it. For this purpose, a set of computational models are employed to figure out in a holistic way the involved phenomena in the interaction between the engine and the exhaust gas aftertreatment system. Firstly, an engine model is implemented to evaluate the effect of the late fuel post-injection pattern on the gas properties at the exhaust aftertreatment system inlet in different steady-state operating conditions. These are selected to provide representative boundary conditions of the exhaust gas flow concerning dwell time, exhaust temperature and O 2 concentration. In this way, the results are later applied to the analysis of the diesel oxidation catalyst and wall-flow particulate filter responses. The dependence of the diesel particulate filter (DPF) inlet temperature is discussed based on the efficiency of each post-injection strategy to increase the exhaust gas temperature. Next, the influence on the dynamics of the regeneration of the post-injection parameters through the change in gas temperature and O 2 concentration is finally studied distinguishing the pre-heating, maximum reactivity and late soot oxidation stages as well as the required fuel consumption to complete the regeneration process.

scholarly journals Tailoring Charge Reactivity Using In-Cylinder Generated Reformate for Gasoline Compression Ignition Strategies

2016 ◽  
Author(s):  
Isaac W. Ekoto ◽  
Benjamin M. Wolk ◽  
William F. Northrop ◽  
Nils Hansen ◽  
Kai Moshammer
Keyword(s):  
Performance Metrics ◽  
Engine Performance ◽  
Combustion Stability ◽  
Gas Temperature ◽  
Exhaust Temperature ◽  
Start Of Injection ◽  
Main Period ◽  
Piston Crevice ◽  
Ignition Characteristics ◽  
Negative Valve Overlap

In-cylinder reforming of injected fuel during an auxiliary negative valve overlap (NVO) period can be used to optimize main-cycle combustion phasing for low-load Low-Temperature Gasoline Combustion, where highly dilute mixtures can lead to poor combustion stability. The objective of this work is to examine the effects of reformate composition on main-cycle engine performance for a research gasoline. A custom alternate-fire sequence with nine pre-conditioning cycles was used to generate a common exhaust temperature and composition boundary condition for a cycle-of-interest. Performance metrics such as main-period combustion stability and total cycle efficiency were collected for these custom cycles. The NVO-produced reformate stream was also separately collected using a dump valve apparatus and characterized in detail using both gas chromatography and photoionization mass spectroscopy. To facilitate gas sample analysis, sampling experiments were conducted using a five-component gasoline surrogate (iso-octane, n-heptane, ethanol, 1-hexene, and toluene) that matched the molecular composition, 50% boiling point, and ignition characteristics of the research gasoline. For the gasoline, it was found that the most advanced NVO start-of-injection (SOI) led to the most advanced main-cycle 10% burn angle. The effect was more pronounced as the fraction of total fuel injected in the NVO period increased. With the most retarded NVO SOI, shorter residence times and piston spray impingement limited the opportunity for injected fuel decomposition. For the gasoline surrogate, the most advanced NVO SOI had reduced reactivity relative to more intermediate NVO SOI, which was attributed to rapid in-cylinder mixing that led to a large amount of fuel quench in the piston crevice. For all NVO periods, combustion phasing advanced as the main-period fueling decreased. Slower kinetics for leaner mixtures were offset by a combination of increased bulk-gas temperature from higher charge specific heat ratios and increased fuel reactivity due to higher charge reformate fractions.

Sign in / Sign up

Export Citation Format

Share Document