The analysis of the diesel engine heat release

MTZ worldwide ◽  
2003 ◽  
Vol 64 (11) ◽  
pp. 32-35
Author(s):  
Gerhard Schöttke ◽  
Helmut Finger ◽  
Volker Schwarz
Keyword(s):  
Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2941
Author(s):  
Wojciech Tutak ◽  
Arkadiusz Jamrozik ◽  
Karol Grab-Rogaliński

The main objective of this study was assessment of the performance, emissions and combustion characteristics of a diesel engine using RME–1-butanol blends. In assessing the combustion process, great importance was placed on evaluating the stability of this process. Not only were the typical COVIMEP indicators assessed, but also the non-burnability of the characteristic combustion stages: ignition delay, time of 50% heat release and the end of combustion. The evaluation of the combustion process based on the analysis of heat release. The tests carried out on a 1-cylinder diesel engine operating at a constant load. Research and evaluation of the combustion process of a mixture of RME and 1-butanol carried out for the entire range of shares of both fuels up to 90% of 1-butanol energetic fraction. The participation of butanol in combustion process with RME increased the in-cylinder peak pressure and the heat release rate. With the increase in the share of butanol there was noted a decrease in specific energy consumption and an increase in engine efficiency. The share of butanol improved the combustion stability. There was also an increase in NOx emissions and decrease in CO and soot emissions. The engine can be power by blend up to 80% energy share of butanol.


Author(s):  
Shuonan Xu ◽  
David Anderson ◽  
Mark Hoffman ◽  
Robert Prucka ◽  
Zoran Filipi

Energy security concerns and an abundant supply of natural gas in the USA provide the impetus for engine designers to consider alternative gaseous fuels in the existing engines. The dual-fuel natural-gas diesel engine concept is attractive because of the minimal design changes, the ability to preserve a high compression ratio of the baseline diesel, and the lack of range anxiety. However, the increased complexity of a dual-fuel engine poses challenges, including the knock limit at a high load, the combustion instability at a low load, and the transient response of an engine with directly injected diesel fuel and port fuel injection of compressed natural gas upstream of the intake manifold. Predictive simulations of the complete engine system are an invaluable tool for investigations of these conditions and development of dual-fuel control strategies. This paper presents the development of a phenomenological combustion model of a heavy-duty dual-fuel engine, aided by insights from experimental data. Heat release analysis is carried out first, using the cylinder pressure data acquired with both diesel-only and dual-fuel (diesel and natural gas) combustion over a wide operating range. A diesel injection timing correlation based on the injector solenoid valve pulse widths is developed, enabling the diesel fuel start of injection to be detected without extra sensors on the fuel injection cam. The experimental heat release trends are obtained with a hybrid triple-Wiebe function for both diesel-only operation and dual-fuel operation. The ignition delay period of dual-fuel operation is examined and estimated with a predictive correlation using the concept of a pseudo-diesel equivalence ratio. A four-stage combustion mechanism is discussed, and it is shown that a triple-Wiebe function has the ability to represent all stages of dual-fuel combustion. This creates a critical building block for modeling a heavy-duty dual-fuel turbocharged engine system.


Author(s):  
J. Shipinski ◽  
P. S. Myers ◽  
O. A. Uyehara

A spray-burning model (based on single-droplet theory) for heat release in a diesel engine is presented. Comparison of computations using this model and experimental data from an operating diesel engine indicate that heat release rates are not adequately represented by single-droplet burning rates. A new concept is proposed, i.e. a burning coefficient for a fuel spray. Comparisons between computations and experimental data indicate that the numerical value of this coefficient is nearly independent of engine speed and combustion-chamber pressure. However, the instantaneous value of the spray burning coefficient is approximately proportional to the instantaneous mass-averaged cylinder gas temperature to the one-third power.


Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 550
Author(s):  
Guohai Jia ◽  
Guoshuai Tian ◽  
Daming Zhang

Taking a plateau high-pressure common-rail diesel engine as the research model, a model was established and simulated by AVL FIRE according to the structural parameters of a diesel engine. The combustion and emission characteristics of D, B20, and B50 diesel engines were simulated in the plateau atmospheric environment at 0 m, 1000 m, and 2000 m. The calculation results show that as the altitude increased, the peak in-cylinder pressure and the cumulative heat release of diesel decreased with different blending ratios. When the altitude increased by 1000 m, the cumulative heat release was reduced by about 5%. Furthermore, the emission trend of NO, soot, and CO was to first increase and then decrease. As the altitude increased, the mass fraction of NO emission decreased. As the altitude increased, the mass fractions of soot and CO increased. Additionally, when the altitude was 0 m and 1000 m, the maximum temperature, the mass fraction of OH, and the fuel–air ratio of B20 were higher and more uniform. When the altitude was 2000 m, the maximum temperature, the mass fraction of OH, and the fuel–air ratio of B50 were higher and more uniform. Lastly, as the altitude increased, the maximum combustion temperature of D and B20 decreased, and combustion became more uneven. As the altitude increased, the maximum combustion temperature of B50 increased, and the combustion became more uniform. As the altitude increased, the fuel–air ratio and the mass fractions of OH and NO decreased. When the altitude increased, the soot concentration increased, and the distribution area was larger.


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.


Author(s):  
Jianjun Zhu ◽  
Peng Li ◽  
Yufeng Xie ◽  
Xin Geng

The effects of compression ratio and fuel delivery advance angle on the combustion and emission characteristics of premixed methanol charge induced ignition by Fischer Tropsch diesel engine were investigated using a CY25TQ diesel engine. In the process of reducing the compression ratio from 16.9 to 15.4, the starting point of combustion is fluctuating, the peak of in-cylinder pressure and the maximum pressure increase rate decrease by 44.5% and 37.7% respectively. The peak instantaneous heat release rate increases by 54.4%. HC and CO emissions are on a rising trend. NOx and soot emissions were greatly decreased. The soot emission has the biggest drop of 50%. Reducing the fuel delivery advance angle will make the peak of in-cylinder pressure and the peak of pressure rise rate increase while the peak of heat release rate decreases. The soot emission is negatively correlated with the fuel delivery advance angle. When the fuel delivery advance angle is 16° CA, the soot emissions increased the most by 130%.


2019 ◽  
Vol 290 ◽  
pp. 06008
Author(s):  
Bogdan Radu ◽  
Alexandru Racovitza

The reduction of Diesel internal combustion engines emissions is one of the major concerns of the engines manufacturers. Despite the fact that the efficiency of the gas post-treatment systems has been significantly improved, decreasing the smoke and the soot from the cylinder inside remains a main research goal. This work is proposing a theoretical study on these pollutants formation for different kinds of direct injection methods. By dividing the in-cylinder injection the heat release characteristic could be modified, leading to different temperature and pressure levels. Using exhaust gas recirculation (EGR) the reduction of the gas temperatures might also be decreased, limiting NOx formation. To evaluate the level of the cylinder gas emissions formation a two-step procedure could be followed. First, by using a numerical calculation system the heat release characteristic can be highlighted concerning a Diesel engine with stratified injection; then, using an experimental relationship applying a large data base, the amount of the gas emissions can be subsequently provided. The authors propose some combinations between injection characteristics and EGR used fractions which could generate successfully results speaking in terms of NOx, soot and smoke formation.


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