Combustion Process In Engine Research Articles

Combustion Process and Performance of HCCI Engines under Different Fuels

Combustion Process and Performance of HCCI Engines under Different Fuels

Kinetic modeling of ion formation during diesel combustion with different fuel injection timing

Ions are formed during the combustion process in internal combustion engines. The measurement of ions inside the combustion chamber produces reliable information about the combustion process. The present study focuses on the formation of ions inside the combustion chamber of diesel engines with different injection timing. For this purpose, a multi-zone thermodynamic model is utilized to simulate the closed cycle of the engine. To understand the kinetic behavior of the ions, the model is connected to an ionic chemical kinetics mechanism with 336 reactions and 81 species. Six important ionic reactions comprising 5 ions are used in the ionic mechanism. Dvode differential equation solver is also employed to calculate the energy and kinetics equations. The developed model has an acceptable accuracy in predicting the performance and pollutants of diesel engines. Based on the results, the ion formation is delayed by delaying the fuel injection timing. The maximum amount of in-cylinder ions depends on injection timing. In-cylinder ion current can predict the start of combustion accurately.

Simulation of alternative fuel combustion process in internal combustion engines

BACKGROUND: The tasks of improving fuel efficiency and environmental performance of engines are interrelated with the technical, economic, resource performance and reliability of their operation. AIM: In this regard, the aim is simulation of the alternative fuels combustion process. METHODS: To achieve this aim, the method for preparing a water-fuel emulsion mixed with diesel fuel has been developed and experimental studies have been carried out with the measurement of toxic components of exhaust gases from diesel engines. RESULTS: As a result of the research, the most optimal droplet sizes of water-fuel emulsions were revealed after 4–6 processing cycles with the smokiness reduction by 3 to 5 times, the NOx reduction by 2 to 3 times, the CO reduction by 20–30%, depending on the operating modes. CONCLUSIONS: As a result of the research, it was found that the use of alternative fuels makes it possible to expand the fuel balance and to improve environmental performance.

Exploring Low-Speed Marine Diesel Engine Parameters through Advanced 3D Visualization with Delaunay Triangulation

The article presents an algorithm for creating software leading to the optimization of the combustion process of marine engines. Parameters determining the Existing Ships Energy Efficiency Index (EEXI) related to ship type, capacity, and propulsion principle are considered. Test data on the characteristics of a two-stroke main engine, model HYUNDAI 6S60MC-C for six types of loads were used as the basis. To present the working field of the engine, the necessary calculations have been carried out and dependencies have been derived for the power and the specific fuel consumption as a function of the revolutions. The implementation includes the development of a small software program using Delaunay's triangulation algorithm to create 3D graphics, as well as Python libraries and methods.

A comprehensive analysis of hydrogen fuel cell integration in fishing vessels

HHO gas is a fuel supplement produced through the electrolysis process of water in an HHO generator, where HHO gas falls under the category of alternative energy and is classified as a new energy source. The fundamental principle of internal combustion engines is generally to convert the chemical energy of liquid fuel into mechanical energy. The production of hydrogen through the electrolysis process is continuously evolving to facilitate the use of environmentally friendly fuels, with potential impacts on engine performance and exhaust gas emissions. This study examines the effect of adding HHO gas to electronic fuel injection (EFI) type-L gasoline engines on exhaust gas emissions and fuel consumption. It has been proven that the addition of HHO gas to the combustion process of gasoline engines, particularly EFI type-D, results in reduced emission levels (CO by 15.31% and HC by 16.27%). Moreover, the introduction of 0.1 Mol of HHO gas into EFI type-L engines through the air filter leads to a significant impact on exhaust gas emissions and a 2.8% increase in fuel consumption compared to not using HHO gas. This could be attributed to the distinct characteristics of EFI systems compared to conventional engines, as they are not accustomed to fuel supplements being injected into the engine.

Investigation of the combustion process in a dual-fuel engine

Modeling of in-cylinder processes occurring in a dual-fuel engine is necessary to obtain the ignition delay period as a function of the angle of rotation of the crankshaft and the subsequent calculation of its effective and environmental indicators. There is a need to identify the theoretical dependence of the fuel combustion process on the parameters that determine the operating modes of a dual-fuel engine, which leads to the need to create a mathematical model that allows the most accurate description of the combustion process, taking into account the maximum possible number of factors. The paper considers the optimization of the parameters of the workflow and the prediction of the performance of the projected and existing dual-fuel engines.

Optical diagnostics in impact of ammonia energy ratio and diesel split ratio on combustion process and flame propagation in an Ammonia-Diesel Dual-Fuel engine

In the context of ammonia-diesel dual-fuel (ADDF) engines, challenges such as ignition difficulties and misfires emerge prominently at elevated ammonia energy ratios. To alleviate these challenges, this study aims to elucidate the effects of ammonia energy ratios (AER) and diesel split ratios (DSR) on the combustion process and flame propagation in an optical ADDF engine configuration. Utilizing optical diagnostics, including flame luminescence and high-speed photography, the study provided insights into combustion boundary conditions specific to ADDF engine operation. The results highlight that an increase in AER to 60 % results in a marked decrease in peak cylinder pressure, peak apparent heat release rate (AHRR), and the in-cylinder pressure rise rate. This is accompanied by a reduction in IMEP from 4.16 bar to 3.24 bar, indicating a decline in combustion efficiency upon greater ammonia addition. Flame luminosity exhibits a shift from a diesel-like blue hue to an ammonia-tinted pale yellow. This change coincides with a significant reduction in soot formation and restrictions in flame area and propagation speed, largely due to ammonia's intrinsically slower burning velocity and its chemical interplay with diesel. Implementing a dual injection approach further accentuates the peak in-cylinder pressure and AHRR, with the second injection playing a crucial role in ignition. Optimizing the DSR to 40 % improves combustion efficiency, attributed to enhanced fuel-oxygen interactions. Conversely, DSR values of 60 % and 80 % pose challenges. A reduction in diesel content in the subsequent injection leads to a leaner blend, subsequently affecting combustion efficiency, as indicated by reduced heat release rate and diminished IMEP. This study emphasizes understanding the ammonia-diesel interaction and the importance of choosing the appropriate DSR to exploit the advantages of ADDF engines.

OpenFOAM mechanical simulations for confronting structural challenges and attaining high-fidelity results

Multi-dimensional models are now a unified collection of tools for simulating the combustion process in internal combustion engines. To address key challenges in combustion technology and to advance our ability to predict, control, and optimize combustion processes through a novel and integrated approach. In this direction, the present study emphasizes the integration of advanced computational fluid dynamics (CFD) techniques with OpenFOAM to conduct a comprehensive analysis of laminar combustion inside the intake manifold. This integrated approach offers a unique and holistic perspective on combustion processes, a perspective that has not been extensively explored in prior research. Furthermore, FVM is introduced as a novel methodology for the efficient and accurate simulation of these multi-physical phenomena, thereby contributing to the advancement of combustion modeling. The analysis focuses on the flammable energy, energy deposition, and combustion inside the intake manifold of an engine. The goal is to create a comprehensive model that accounts for the intricate interactions between thermal energy, velocity, and species concentration, ultimately leading to a deeper insight into combustion phenomena. The maximum flammable energy is observed near the outlet of the considered intake manifold.

Analysis of Troubleshooting Effect on the Performance of Gas Engine G-102 B (TBG620 V16K) in Central Processing Area of PT. XYZ

PT. XYZ is a part of the largest oil and Gas Company in Indonesia, responsible for managing and developing oil and gas production activities in the East Java. The Central Processing Area serves as the facility for processing fluids produced from the East Java fields. The processed output consists of three phases: Gas, Oil, and Water. The operation of the Gas Engine G102-B TBG620 V16K running 24 hours a day to generate electricity at the central processing area of PT. XYZ requires regular maintenance, including scheduled preventive maintenance and unplanned or corrective maintenance. In the event of troubleshooting, such as a decrease in temperature in chamber 2B or a temperature sensor reading of 280 °C in that chamber, immediate corrective maintenance is necessary. Based on observations conducted in the power plant area, two possibilities causing the temperature decrease in that chamber were identified. The first possibility was the need for spark plug replacement, and the second was a malfunctioning temperature sensor resulting in incorrect readings. Therefore, the spark plug replacement was performed first, requiring a gas engine shutdown for approximately 2 hours for repairs. After the spark plug replacement, it was discovered that there was no change in the temperature reading in chamber 2B, which remained at 280 °C. Hence, the corrective maintenance performed did not have a significant impact because the issue was caused by a faulty temperature sensor. However, it was observed that there was a 1.16% increase in the generated power compared to before the corrective maintenance was conducted. The difference in power output could be attributed to variations in the quality of gas used in the combustion process of the gas engine.

Effects of Turbulence‐Induced Blade Position on Flow and Combustion in a Wankel Rotary Engine

Aiming at the problem of low turbulent velocity and incomplete combustion in the combustion process of the Wankel rotary engine (WRE), and setting turbulence‐induced blade (TIB) in the combustion chamber recess is an effective means to enhance the turbulent motion and promote combustion. Carifying the optimal arrangement position of TIB can get better combustion performance. Therefore, a computational fluid dynamics (CFD) simulation model of a WRE with TIB was established in this paper. Based on the differential pressure perturbation mechanism, the influence of the arrangement position of the TIB on the flow field and combustion performance were analyzed. The results showed that when the ratio of blade arrangement distance is less than 0.66, the pressure difference between the leading and trailing of the blade is small. At this time, the in‐cylinder flow is mainly disturbed by the forced disturbance of the TIB, the increase of the turbulent velocity is not obvious, and the diffusion velocity of the flame to the rotor direction is small. When the ratio of blade arrangement distance is greater than 0.66, the pressure difference between the leading and trailing of the blade is large. At this time, the In‐cylinder flow is affected by the pressure difference flow in addition to the forced disturbance of the TIB. The turbulent velocity is effectively enhanced, and the flame velocity is fast to the rotor direction. When the ratio of blade arrangement distance is 0.66, it shows the best combustion performance, and the indicated work is the largest. Compared to the scheme without TIB, the indicated work is increased by 16%.

Research on the impacts of GPF on RDE emission behaviors

In this research, RDE tests were carried out on a pre-China 6 TGDI vehicle in the two cases of installing or not installing GPF to explore the impacts of GPF on RDE emission behaviors. The results indicated that the GPF can effectively filter PN emissions, especially at low speed, high load engine operating conditions, where the PN emissions can be reduced to about 1/200 of the original emissions. For TGDI vehicles, the installation of GPF can reduce the RDE PN emissions by more than 30 times, which indicates that the GPF is the key post-processing device for TGDI vehicles to meet the China 6 regulation. And in the upgrade process of China 5 vehicles to China 6 vehicles, especially for TGDI vehicles, the engine, the post processor and the turbocharger all needs re-calibrating or re-matching to concur a series of problems the back pressure raise caused by the installation of GPF, which may bring deterioration of engine combustion process, decrease of catalyst temperature and similar conditions that will worsen the vehicle emissions.

Numerical Investigation of Different Combustion Models for Dual‐Fuel Engine Combustion Processes

AbstractThe combustion process of a dual‐fuel engine was calculated by characteristic timescale model (CTM), eddy breakup model (EBM), and coherent flamelet model (CFM) to verify the accuracy of the combustion models. The results show that the peak pressure calculated by EBM is 2.78 % higher than the experimental value, and the peak pressure calculated by CFM is closest to the experimental value. The EBM is the most accurate for CO2 emissions. The deviation of CO emissions from the experimental values calculated by CTM is the smallest (< 1 %). The NOx emission calculated by CTM is good agreement with the experimental value at low speed, and EBM is in best agreement with the experimental value at high speed. The hydrocarbon emission calculated by CFM is the most accurate, with a deviation of less than 0.6 %.

INFLUENCE OF SINTERING TEMPERATURE ON THE STRUCTURAL OF Mg2Si0.3Sn0.7 ALLOY PREPARED BY POWDER METALLURGY

The efficiency of energy consumption can be improved by reducing the heat lost during the combustion process of automotive engines. By converting waste heat energy into other energy sources that can be used directly, efficiency can be achieved. Mg2Si0.3Sn0.7 is a metal alloy that has the potential to convert waste heat into power. In this research, we used the powder metallurgy method to synthesize the Mg2Si0.3Sn0.7-based alloy. A mixture of Mg, Si, and Sn powders that had been milled for 2 hours was insulated in the stainless-steel tube to avoid oxidation and combustion. Heat treatment was conducted with temperature variations of 700, 750, and 800°C for 4 hours to investigate the influence of sintering temperature on the crystal structure of the Mg2Si0.3Sn0.7-based alloy. The microstructure and formation of the material were examined using an X-ray diffractometer (XRD) and a scanning electron microscope (SEM). Based on XRD analysis, it was found that the Mg2Si0.3Sn0.7 phase and a small amount of magnesium oxide (MgO) phase have formed. Due to the phase transition from Mg2Si0.3Sn0.7 to Mg2Sn at a sintering temperature of 800°C, the cubic lattice constant -a changes from 0.6631 nm to 0.6765 nm.

Effects of Methanol Addition on the Combustion Process of the Methanol/Diesel Dual-Fuel Based on an Optical Engine

The combustion process of traditional diesel engines is mainly determined by the injection timing of diesel. There is a trade-off relationship between the soot and NOx (nitrogen oxides) during this combustion process, making it difficult to reduce these two emissions simultaneously. The use of methanol can not only solve the above problem, but also replace some fossil fuels. However, the effects of methanol injection into the intake duct on the flame propagation in diesel/methanol dual-fuel engines is not yet clear, and there is relatively little research on it. The effects of methanol addition on the combustion process of diesel/methanol dual fuel (DMDF) were achieved based on a modified optical engine in this paper. One injector is installed on the intake inlet to inject methanol, and the other injector is installed in the cylinder to inject diesel in two stages before the top dead center of compression. There are three tests conducted separately in this paper. Firstly, the effects of the methanol ratio (40%, 50%, 60%, and 70%) on the combustion process are investigated, with the total heat remaining unchanged. Secondly, the effects of the pre-injection mass of diesel (20%, 30%, 40%, and 50%) on the combustion process are investigated, which keeps the total diesel mass unchanged. Finally, the effects of the total mass of diesel on the combustion process are investigated while maintaining the mass of methanol unchanged. The dual-fuel combustion process is recorded by a high-speed camera. A combustion analyzer and other equipment were used to analyze the combustion. The results showed that CA10 is delayed, the pressure and the heat release rate (HRR) are reduced, and the number of pixels of the KL factor (KL) decreases significantly with the increasing methanol ratio. CA10 and CA50 are advanced, the pressure and HRR decrease, and the KL increases when the mass of pre-injected diesel increases. CA10 and CA50 are advanced, respectively, and CA90 is postponed due to the increase in diesel mass. The pressure and HRR increase, and the KL increases when the total mass of diesel increases.

Numerical Study on the Effects of Partial Oxidation Fuel Reforming (POFR) on the Performance of a Natural Gas Engine

Due to the issues of low flame speed and high CH4 emissions for a natural gas engine, investigations into the partial oxidation fuel reforming (POFR) method used in natural gas engines to blend H2 have become increasingly valuable. In this paper, the combustion process, engine performance, and emissions of a natural gas engine with fuel-reforming gases blended together have been numerically studied. The results show that a higher fuel-reforming ratio can effectively improve the engine combustion performance, especially at lean-burn conditions. Combustion with reformed gases can increase the thermal efficiency by almost 2% at the full-load condition, whereas fuel reforming significantly affects the natural gas engine’s power performance. Furthermore, CH4 and NOX emissions decrease significantly with increasing fuel-reforming ratio. In conclusion, fuel reforming for a natural gas engine has a promising future in reducing greenhouse gas emissions and improving economic performance.

Construction and verification of dual-fuel engine combustion model

In order to achieve real-time mapping and online optimization of the combustion process of a dual-fuel engine that is in prolonged operation, this paper is the first to combine the Wiebe function with a deep learning neural network to propose a zero-dimensional (0-D) combustion prediction model for a biodiesel-diesel dual-fuel engine. First, the parameters of the double Wiebe functions are calculated by the Pelican Optimization Algorithm (POA), and the operating parameters and Wiebe parameters are used as input and output parameters of neural networks, respectively, to construct parameter identification models. Then, the combustion process is simplified and reconstructed by combining the Wiebe function with the deep learning neural network, and a 0-D prediction model based on the hybrid model-driven and data-driven method is established, which can further obtain combustion results such as cylinder pressure curve and indicated mean effective pressure (IMEP). The results show that the coefficient of determination (R2) value of the dual-fuel engine 0-D prediction model based on the double Wiebe function combined with POA–CNN–Bi-LSTM is 0.9827, and the model has good prediction accuracy and generalization. The development of the combustion model provides reliable numerical model support for the online evaluation and optimization of dual-fuel engine performance.

Evaluation of an integrated electric power generation system with natural gas engines operating in dual mode through heat recovery with thermoelectric devices for hydrogen production

In the present investigation, an environmental, thermal, economic, and social analysis of an integrated system is carried out, which has as its function the production of hydrogen through the recovery of residual thermal energy from exhaust gases. The proposed integrated system consists of a thermoelectric generator and a hydrogen production bench based on the water electrolysis process. For the development of the research, an internal combustion engine fueled with natural gas was used, operating under four load conditions (25%, 50%, 75%, and 100%). From the environmental assessment, it is demonstrated that the implementation of the integrated system allows a decrease of 12.30%, 6.26%, and 7.90% in CO, CO2, and HC emissions. However, the addition of hydrogen causes a 9.9% increase in NOx emissions. Additionally, the implementation of the integrated system allows a 4.9% decrease in brake specific fuel consumption and a 4.9% increase in engine thermal efficiency. The improvement in engine thermal performance contributes to the 7% reduction in engine operating costs. On the other hand, it demonstrates an 8.7% reduction in the environmental and social impact cost and a 9% reduction in the ecological cost. Additionally, the integrated system minimizes the cost of environmental and social impact, as well as the ecological cost of polluting gases CO, CO2, and HC. The mixture of natural gas and hydrogen allows for a 4.70% and 7.59% increase in pressure and maximum heat release rate. In general, the proposed integrated system is a way to harness the thermal energy of exhaust gases for hydrogen production. In this way, it is possible to obtain an auxiliary fuel that improves the efficiency of the combustion process of the natural gas engine. This allows for minimizing energy losses in self-generation activities in Colombia, achieving better energy management and a reduction in operating costs.

Evaluation of a pressure sensing glow plug in terms of its application possibility to control the combustion process of a hydrogen-powered spark-ignition engine

The article contains the results of an analysis of the suitability of a pressure sensing glow plug for use in a hydrogen engine control system. Due to the properties of hydrogen, the process of its combustion in spark-ignition engines is significantly different from the classic fuels. It is planned to use the pressure sensor signal to control the combustion process to obtain high power and efficiency, with the lowest possible emission of nitrogen oxides, which is the main harmful component of hydrogen engines. After an initial assessment of suitability, it was decided to use a pressure sensing glow plug. This choice is dictated by the low price, good availability and high durability of these sensors. The preliminary tests were carried out using a low-power single-cylinder SI engine coupled with a 48V generator. The tests were carried out for several values of engine speed and load of the generator and for classic gasoline with a research octane number (RON) of 95. In order to obtain an increased pressure rise rate in the cylinder, as for hydrogen fueling, the engine operation was also tested with unmodified light gasoline used as solvent, which is characterized by a significantly lower RON value. The use of a reference pressure sensor in the cylinder made it possible to determine the behavior of the PSG in various operating conditions. The tests revealed that the differences in the pressure waveforms registered with both sensors can be systematized depending on the engine speed and its load.

Analysis of the Exothermic Reaction of Flame Ignition in the Combustion Chamber of a Gas Turbine Unit

This article analyses the exothermic reaction of flame ignition in the combustion chamber of a gas turbine unit, which is characteristic of combustion chambers operating on traditional hydrocarbon fuels. The combustion of gases as an explosive process in confined and semi-enclosed areas remains a poorly understood section of thermal physics. Without a detailed review of the physical and chemical processes taking place in the combustion chamber, it cannot be said whether the gas turbine unit will run sustainably. It is also important to know what combustion modes are in principle possible after a loss of stability in the combustion chamber in order to take action against this in advance. To describe flame ignition and quenching in the flow of the fuel–air mixture through a combustion chamber, a system of differential conservation equations of energy and reactive species supplemented with the equation of state is used. Nonstationary combustion processes in gas-turbine engines were studied, and flame ignition and blow-off were determined by the heat balance and by the continuity of chemical processes. Calculation methodologies for various operating modes of the combustion chamber of a gas turbine unit are developed and realized. The results of the calculations that were carried out are presented with graphical interpretation and with their analysis provided in sufficient detail. Based on this analysis, recommendations are then provided. From the graphs, it can be observed that the combustion chamber of a gas turbine unit reaches its maximum limit of stable operation at the optimum value of the reduced flow velocity in the openings of the air supply to the combustion and the mixing zones of the flame tube (λOC)opt = 0.22 when the fuel–air mixture is at maximum depletion, ensuring that combustion does not stop and flame failure does not occur. The topic of this article relates to the intensification of hydrocarbon fuel combustion and the technological improvement of combustion chambers in gas turbine units. This topic is of exceptional importance and relevance, emphasizing its significance. The purpose of this work is to develop and implement a methodology for calculating various modes of operation of the combustion chamber of a gas turbine unit.

Modeling the impact of the fuel injection strategy on the combustion and performance characteristics of a heavy-duty GCI engine

Gasoline compression ignition (GCI) is a promising strategy to achieve high thermal efficiency and low emissions with limited modifications to the conventional diesel engine hardware. It is a partially premixed concept, which derives its superiority from higher volatility and longer ignition delay of gasoline-like fuels combined with higher compression ratio typical of diesel engines. The present study investigates the combustion process in a GCI engine operating with different injection strategies using computational fluid dynamics (CFD). Simulations are carried out on a single cylinder of a multi cylinder heavy-duty compression ignition engine, which operates at a compression ratio of 17:1 and an engine speed of 1038 rev/min. Two different injection strategies viz., late injection (LI), and early pilot injection (EP) are investigated to understand their impact on combustion and performance of the engine. Renormalized group (RNG) k-ε model is used to describe in-cylinder turbulence and KH RT model is used to simulate the fuel spray breakup. The developed CFD methodology is validated against relevant experimental data under a wide range of operating conditions for each injection strategy. The developed CFD methodology was found to capture the engine combustion behavior quite well. Based on the validated CFD model, the differences in the progress of combustion event for the two injection strategies is highlighted. It was found that a larger pilot fuel mass fraction results in a steeper rise in the initial heat release rate which in turn influences the transition to mixing controlled combustion. In line with the experimental data, the study showed that the late pilot injection strategy with three injection pulses, results in higher performance compared to the other conditions.