scholarly journals Mechanism of Emission Reduction in HSDI Diesel Engine: Split Injection

2015 ◽  
Vol 09 (2) ◽  
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Temporal Distribution ◽  
Reaction Rates ◽  
Chemical Mechanism ◽  
Symmetric Model ◽  
Diesel Combustion ◽  
Split Injection ◽  
Engine Combustion ◽  
Experimental Values

In order to meet the stringent emission standards significant efforts have been imparted to the research and development of cleaner IC engines. Diesel combustion and the formation of pollutants are directly influenced by spatial and temporal distribution of the fuel injected. The development and validation of computational fluid dynamics (CFD) models for diesel engine combustion and emissions is described. The complexity of diesel combustion requires simulation with many complex interacting sub models in order to have a success in improving the performance and to reduce the emissions. In the present work an attempt has been made to develop a multidimensional axe-symmetric model for CI engine combustion and emissions. Later simulations have been carried out using split injection for single, double and three pulses (split injection) for which commercial validation tool FLUENT was used for simulation. The tool solves basic governing equations of fluid flow that is continuity, momentum, species transport and energy equation. Using finite volume method turbulence was modeled by using RNG K-ɛ model. Injection was modeled using La Grangian approach and reaction was modeled using non premixed combustion which considers the effects of turbulence and detailed chemical mechanism into account to model the reaction rates. The specific heats were approximated using piecewise polynomials. Subsequently the simulated results have been validated with the existing experimental values. The peak pressure obtained by simulation for single and double is 10% higher than to that of experimental value. Whereas for triple injections 5% higher than to that of experimental value. For quadruple injection the pressure has been decreased by 10% when compared to triple injection.NOX have been decreased in simulation for single, double and triple injections by 15%, 28% and 20%.For quadruple injection NOX were reduced in quadruple injection by 20% to that of triple injection. The simulated value of soot for single, double and triple injections are 12%, 22% and 12% lesser than the experimental values. For quadruple injection the soot levels were almost negligible. The simulated heat release rates for single, double and triple were reduced by 12%, 18% and 11%. For quadruple injection heat release is reduced same as to that of triple injection.

Simulation of n-Heptane and Surrogate Fuels for Advanced Combustion Engines (FACE) in a Single-Cylinder Compression Ignition Engine

2013 ◽  
Author(s):  
Joseph Taglialegami ◽  
Gregory Bogin ◽  
Eric Osecky ◽  
Anthony M. Dean
Keyword(s):  
Diesel Engine ◽  
Physical Properties ◽  
Heat Release ◽  
Chemical Mechanism ◽  
Computational Time ◽  
Combustion Engines ◽  
Single Cylinder ◽  
Advanced Combustion ◽  
The Face ◽  
Single Chemical

A CFD model of a HATZ diesel engine was developed for the purpose of simulating low temperature combustion (LTC) of surrogate diesel fuels for the Fuels for Advanced Combustion Engines (FACE). Initial validation of the model was performed using n-heptane data from a single cylinder HATZ diesel engine. Simulations were run with both a detailed n-heptane mechanism and several reduced mechanisms to determine the suitability of using a reduced mechanism to capture the main ignition characteristics and emissions. It was found that a 173 species n-heptane mechanism predicts start of combustion (SOC) within 0.5 crank angle degrees of the detailed 561 species mechanism. The 173 species mechanism required 27 hours of computational time to reach the end of the simulation whereas the 561 species detailed mechanism required 41 hours under the same conditions. Two additional reduced mechanisms, containing 85 and 35 species, were provided reasonable accuracy with a computational time of 8 hours and 2 hours, respectively. Due to the varying physical and chemical properties of the FACE surrogates, a sensitivity analysis of the effects of the physical properties was conducted by changing the n-heptane physical properties to those of n-hexadecane while keeping the chemistry the same. As expected, when the fuel properties of n-hexadecane (which is less volatile than n-heptane) were used with the n-heptane kinetics, SOC was delayed and the net heat release rate was reduced. The FACE fuels were developed to fulfill the need for research grade fuels that are able to represent common refinery stream fuels. Since the FACE fuels consist of hundreds of fuel components, it is not feasible to model the actual FACE fuels in a full-scale engine model. An alternative is to develop surrogates consisting of relatively few species for which detailed mechanisms are available. Even then this mechanism would need to be reduced to make the computation practical. For this work, a detailed diesel surrogate mechanism was reduced from 4016 species to 1046 species to match the characteristics for FACE fuels 1, 3, 5, 8, and 9. The surrogates only contain 4–7 species. Using the single chemical mechanism to represent five surrogate FACE fuels, it was found that ∼200°C of air preheat was required to achieve autoignition in the HATZ model compared to the 130°C of air preheat required experimentally. Initial runs have found that there were similar trends in SOC and heat release between the FACE fuel surrogate experiments and simulations for the respective fuels. Future work will require improvements on the single chemical mechanism to represent the five surrogate FACE fuels.

Investigation into Some Aspects of the Computation of Diesel Engine Combustion

1976 ◽  
Vol 190 (1) ◽  
pp. 467-475 ◽  
Author(s):  
T. J. Williams ◽  
N. D. Whitehouse
Keyword(s):  
Diesel Engine ◽  
Computational Cost ◽  
Experimental Results ◽  
Diesel Combustion ◽  
Combustion Models ◽  
Engine Combustion

SYNOPSIS The effect upon computational cost and accuracy of various assumptions in diesel combustion models was investigated by comparing the performance of a range of models and by comparing the results of computation with experimental results.

Consideration of split injection strategy for marine diesel engine combustion process

2019 ◽  
Author(s):  
Frengki Mohamad Felayati ◽  
Semin ◽  
Muhammad Badrus Zaman ◽  
Ayudhia Pangestu Gusti
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Marine Diesel Engine ◽  
Split Injection ◽  
Injection Strategy ◽  
Engine Combustion ◽  
Marine Diesel

Heat Release Analysis of Oxygen-Enriched Diesel Combustion

1993 ◽  
Vol 115 (4) ◽  
pp. 761-768 ◽  
Author(s):  
D. Assanis ◽  
E. Karvounis ◽  
R. Sekar ◽  
W. Marr
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Oxygen Enrichment ◽  
Operating Conditions ◽  
Diesel Combustion ◽  
The Novel ◽  
Pressure Data ◽  
Engine Operation ◽  
Combustion Simulation ◽  
Release Analysis

A heat release correlation for oxygen-enriched diesel combustion is being developed through heat release analysis of cylinder pressure data from a single-cylinder diesel engine operating under various levels of oxygen enrichment. Results show that standard combustion correlations available in the literature do not accurately describe oxygen-enriched diesel combustion. A novel functional form is therefore proposed, which is shown to reproduce measured heat release profiles closely, under different operating conditions and levels of oxygen enrichment. The mathematical complexity of the associated curve-fitting problem is maintained at the same level of difficulty as for standard correlations. When the novel correlation is incorporated into a computer simulation of diesel engine operation with oxygen enrichment, the latter predicts pressure traces in excellent agreement with measured pressure data. This demonstrates the potential of the proposed combustion simulation to guide the application of oxygen-enriched technology successfully to a variety of multicylinder diesel systems.

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