MR-Process consists two stage combustion mechanism in twin swirl flow conditions which is created by special design of 2 intake manifolds and combustion chamber (CC) geometry of a 4-valve engine. It ...is a question if it is possible to apply a Quasi MR-Process by modifying CC of a 2-valve engine which has only one intake manifold. Previously engine tests were successfully conducted on a 2-valve and modified CC (MR-2 CC) single cylinder test engine with one intake manifold using LPG and diesel fuels. Nevertheless because of there is no optical access inside the engine, it is not clear whether required twin swirl flow (to create Quasi MR-Process) occurs inside CCs of proposed 2-valve engines. In this study, our aim is to improve the clarification of the swirl motion and air-fuel mixture formation for said Quasi MR-Process CC application in 2-valve diesel engines. Two different CC geometries were investigated in terms of Quasi MR-Process generation potential by using KIVA3V-R2 code. CFD predictions of air flow motion, air-fuel mixture formation and diesel spray combustion were analyzed and compared with each other in a methodical manner. The results showed that 2 valve engine CC is not capable of creating optimal twin swirl. However, it is presented that generation of twin swirl can be improved by application of modified (MR-2 CC) piston head design.
Managing waste plastic is becoming a severe challenge. The industry and researchers have been looking at various opportunities in line with circular economy principles for effective plastic waste ...management. In that context, plastic waste valorization to oil as a substitute to fossil fuel has gained recent attention. In the literature, there exist few studies showing the use of oil derived from waste plastics in blends with other conventional fuels in compression ignition (CI) engines; however, studies on CI engines that use 100% waste-derived fuels are limited. Additionally, the exhaust gas recirculation (EGR) concepts and the use of nano-coated chambers (like pistons, valves and cylinders heads) have been gaining interest purely from the engine performance enhancement perspective in recent years. Therefore, this study investigates engine performance by combining exhaust gas from the EGR technique and waste plastic oil (WPO) as inputs, followed by thermal coatings in the CI engine chambers for performance enhancement. The experimental setup of the engine is developed, and the engine’s piston, valve and cylinder heads are coated with Al2O3-SiO4 material. The CI engine’s energy, emission, and combustion characteristics are tested, followed by a scenario analysis compared with diesel-only fuel. The tested scenarios include a WPO + Al2O3-SiO4, WPO + Al2O3-SiO4 + 10% EGR, and WPO + Al2O3-SiO4 + 20% EGR. The results show that the piston crown’s thermal coating increased the combustion performance. Significant impacts on the carbon monoxide, hydrocarbons, and smoke characteristics are observed for different %EGR rates. The results also showed that the cooled EGR engine has decreased nitric oxide emissions. Overall, the results show that WPO combined with exhaust gas could be a potential fuel for future CI engines.
•CAI combustion has many advantages respect to SI combustion.•Main advantages: low NOx, better engine stability, higher fuel efficiency.•The main drawback is a significantly more complex combustion ...control.•VVT position, F/A ratio and EGR rate can be used for control.•EGR is a very effective way to avoid knock and to improve the fuel efficiency - NOx trade-off.
The need to reduce the emissions coming from automobiles encourages the attempts to study different engine configurations and new combustion strategies. In this case, a two stroke engine able to operate in Controlled AutoIgnition (CAI) and Spark Ignition (SI) combustion modes is studied, with the purpose of getting lower NOx and CO2 emissions than with other currently employed solutions. The engine configuration retained for the research is a uniflow scavenging configuration with intake ports in the cylinder liner and exhaust valves in the cylinder head. These valves are controlled by a Variable Valve Timing (VVT) system. The scavenging is guaranteed by an external blower driven by the crankshaft. Finally, the fuel supply is performed by a direct injection (DI) air-assisted fuel injection system.
Through this paper the adjusting parameters to control the engine operation, as well as their influence on the CAI and SI combustion modes have been studied, providing the most relevant information and knowledge for controlling and optimizing the engine performance. Once these controlling parameters were studied, an EGR system was introduced in order to analyze the effect of this other parameter over the combustion process, as well as to determine the potential benefits of introducing such a system in this type of engines.
To aid in addressing global climate change and reduce automobile carbon emissions, the thermal efficiency of engines must be improved. By altering the structural design of an engine body (including ...the cylinder blocks and cylinder heads), a rapid combustion model with a compression ratio of 16 and a maximum tumble ratio of 3.94 was developed that improved the combustion speed. Through synergistic matching of cooled exhaust gas recirculation with lean burn technology, when the exhaust gas recirculation rate was 20% and the air-fuel ratio was 20, the effect of reducing NOx emission and knocking reached the optimum level. When an electronic water pump and dual thermostat technology were used, the temperature change at the combustion chamber wall of each cylinder was <3%, and when the engine ran at speeds of up to 2400 r/min and torque of up to 60 Nm, the coolant temperature could reach 105°C, thereby reducing both heat dissipation and friction losses. The maximum thermal efficiency of the new DHE16GDI engine developed based on the DAM16N engine model increased by approximately 4.4%, and the contents of the major pollutants NOx and CO and the total hydrocarbon content were reduced by approximately 43.1%, 34.8% and 8.3%, respectively.
Environmental effects of vehicle exhausts from internal combustions engines which accounts for about 90% of vehicles on the roads is posing a major threat to environmental safety, and it only ...continues to surge at an alarming rate now than ever. With diesel engines being the most cost-effective prime mover readily available, their contribution to environmental pollution problems is humongous. The harmful contaminants from diesel exhausts are particulate matter (PM) and hydrocarbon and nitrogen oxides (NOx). So, efforts to curb environmental pollution are the need of the hour by making necessary improvements to reduce their local and global environmental impact. In this study, examine the effects of yttria- and alumina-stabilised zirconia coating on the piston head and cylinder lining of a single-cylinder diesel engine, as well as its performance and emissions. Various dosing amounts of nanoparticles of aluminium oxide were utilised as additives to diesel fuel in this study, on both coated and uncoated internal combustion engines. Many coated engine metrics improved significantly as a result of the research. The brake thermal efficiency has increased by 2.1 percent as compared to a conventional uncoated diesel engine, while brake-specific consumption has dropped by 3%, resulting in a reduction in dangerous chemicals.
If the circular holes of an engine cylinder head are distorted, cracked, defective, etc., the normal running of the equipment will be affected. For detecting these faults with high accuracy, this ...paper proposes a detection method based on feature point matching, which can reduce the detection error caused by distortion and light interference. First, the effective and robust feature vectors of pixels are extracted based on improved sparse Haar-like features. Then we calculate the similarity and find the most similar matching point from the image. In order to improve the robustness to the illumination, this paper uses the method based on image similarity to map the original image, so that the same region under different illumination conditions has similar spatial distribution. The experiments show that the algorithm not only has high matching accuracy, but also has good robustness to the illumination.
Reactivity Controlled Compression Ignition (RCCI) is one of the most promising solutions among the low temperature combustion concepts, in terms of thermal efficiency and pollutant emissions. ...However, for values of brake mean effective pressure higher than 10 bar, in-cylinder peak pressure rise rates tend to be too high, limiting the specific power of any 4-Stroke (4S) engine. Such a limitation can be canceled by moving to the 2-Stroke (2S) cycle. Among many alternatives, the “Uniflow” scavenging system with exhaust poppet valves on the cylinder head allows the designer to reproduce the same identical combustion patterns of a 4-stroke RCCI engine, while increasing the indicated power output. The goal of the paper is to explore the potential of a 2-stroke RCCI engine, on the basis of a comprehensive experimental campaign carried out on a modified automotive 2.0 L, 4-stroke, four-cylinder, four-valve diesel engine. The developed prototype can run with one cylinder operating in 4-stroke RCCI mode (gasoline–diesel), while the others work in the standard diesel mode. A One Dimensional-Computational Fluid Dynamics (1D-CFD) model has been built to predict the performance of the same prototype, when operating all four cylinders in RCCI mode. In parallel, an equivalent 2-stroke RCCI virtual engine has been developed, by means of 1D-CFD simulations and empirical assumptions. A numerical comparison between the 4S and the 2S engines is finally presented, in terms of performance and emissions at full load. The study demonstrates that a 2S RCCI engine can maintain all of the advantages of the RCCI combustion, strongly reducing the penalization in terms of performance, in comparison to a standard 4S diesel engine.
Conventional fatigue tests on complex components are difficult to sample, time-consuming and expensive. To avoid such problems, several popular machine learning (ML) algorithms were used and compared ...to predict fatigue life of gray cast iron (GCI) with the complex microstructures. The feature analysis shows that the fatigue life of GCI is mainly influenced by the external environment such as the stress amplitude, and the internal microstructure parameters such as the percentage of graphite, graphite length, stress concentration factor at the graphite tip, matrix microhardness and Brinell hardness. For simplicity, collected datasets with some of the above features were used to train ML models including back-propagation neural network (BPNN), random forest (RF) and eXtreme gradient boosting (XGBoost). The comparison results suggest that the three models could predict the fatigue lives of GCI, while the implemented RF algorithm is the best performing model. Moreover, the
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curves fitted by the Basquin relation in the predicted data have a mean relative error of 15% compared to the measured data. The results have demonstrated the advantages of ML, which provides a generic way to predict the fatigue life of GCI for reducing time and cost.
Purpose
Paper aims to an alloy development study was carried out to increase the mechanical properties of cylinder heads.
Design/methodology/approach
AlSi12 alloys are used to manufacture the ...compressor head cylinder by high-pressure casting for easy casting and superior properties. Therefore, 1.1%, 2.4% and 3.1% Mg were added to AlSi12. The microstructures of the produced samples were characterized by optical microscope, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction methods. Hardness and tensile tests as well as Charpy impact tests were performed. Wear tests were also carried out on the pin-on disc tester, and then the wear performance was examined on the tester, which simulates the actual operating condition.
Findings
AlSi12 has primary Si and eutectic Si in the Al matrix. However, alloys of Mg with AlSi12 have other intermetallics such as Mg2Si and ß-Fe, as well as primary Si and eutectic Si. Hardness and tensile strength as well as improved wear performance with increased Mg content.
Originality/value
In this study, wear performance test to simulate the operation of the cylinder head produced by high pressure casting from AlSi12 alloy moreover tensile test, hardness test and impact test were performed. Therefore, in this study, the wear performance of the compressor head produced by high-pressure casting method by adding three different amounts of Mg to AlSi12 alloy was investigated.
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