Engine Cylinder Research Articles

The study on the conversion of single cylinder engine into homogeneous charge compression ignition (HCCI) engine

The study on the conversion of single cylinder engine into homogeneous charge compression ignition (HCCI) engine

Investigating the fractal dimension of flame fronts of the biodiesel-diesel blends combustion in atmospheric conditions and engine cylinders: An experimental study

The fractal dimension of the flame front is an important parameter that quantifies the degree of flame folding and twisting as well as the instantaneous mass burning rate. Due to the geometric nature of flame surface folding, the fractal approach is also considered one of the most appropriate methods in power law modelling. Although biodiesel fuel is an important renewable fuel, studies on the fractal dimension of the flame during the combustion of biodiesel and its blends are limited. To address this research gap, combustion assays of biodiesel-diesel mixtures were systematically conducted within a coaxial diffusion burner and a diesel engine. High-resolution images of the evolving combustion flames were captured using a high-speed video camera. Digital image processing was applied to facilitate the extraction of key features from these images. Through the differential box counting (DBC) method, the fractal dimensions of the flame fronts were derived. A comprehensive analysis was carried out, revealing the influence of various parameters on the flame's fractal dimensions, including the biodiesel-diesel blend proportion, blend temperature, engine operational speed, and air flow rate. The results highlight that the fractal dimension undergoes a non-monotonic variation as biodiesel content increases. Specifically, the combustion of B25 blend exhibited the minimum fractal dimension, while the B100 blend showed the maximum. Further, in engine environments, peak fractal dimensions were observed to occur earlier at higher speeds (2200 r/min) with an increase in the biodiesel ratio. These insights not only bridge a critical knowledge gap in power-law modeling for biodiesel combustion but also offer a quantitative understanding of how blend ratios and engine conditions affect flame fractal properties.

Analysis and prediction of automotive running status based on vibration detection system

In order to detect and diagnose the operating status without disassembling automobile parts, engine speed and suspension status were tested and analyzed based on vibration detection technology. Based on a DSP processor and an acceleration sensor, the speed of a single cylinder engine was tested under steady-state and transient conditions, respectively. Using the cepstrum method, the vibration signals were collected at different speeds are processed, the fundamental frequency was extracted, and the engine speed information was obtained. According to the speed verification using the Otsu EWT method, the maximum relative error of engine speed was less than 1.5 %, and the error decreases as the speed increases. In order to ensure the reliability of suspension vibration signals, the overall structure and safety of the vibration characteristic detection scheme were designed. Due to the limited sampling frequency of suspension load status sensor data, the EMD method was adopted to process dynamic load signals, which had a good separation effect on suspension vibration signals.

Mathematical model of the condensation process in a cylinder of a piston engine

BACKGROUND: In recent years, there has been a trend of increasing activity towards the development of polar territories. A characteristic feature of the North is negative ambient temperatures that have a negative impact on the condition of piston engines of ground transport, mobile and stationary power plants and labor saving tools. An engine is the least adapted unit for use in such conditions. There is a chain of negative factors that consistently links negative ambient temperatures, in which the equipment is operated, and the condition of the mechanisms and engine systems. The primary link of this chain is condensation processes. The existence of condensation processes during low-temperature operation of the engine has been experimentally proved. The latter takes place when warming up in conditions of negative ambient temperatures. The question «How much water changes the state during the warm-up period?» arises. AIMS: Development of a mathematical model that makes possible to obtain unbiased information about the activity of condensation processes and to estimate the amount of water that changes the state during the warm-up period. METHODS: Solving the given tasks is based on classical theories describing operational processes of boilers. The high labor intensity and significant financial costs in organizing such experiments require the search for new research methods. Mathematical models help to solve the task of defining the mass amount of water condensing in a cylinder of a piston engine computationally. RESULTS: The mathematical model that is characterized by its adaptation to piston engines and is capable of determining the mass amount of water changing the state during the warm-up period iteratively, using the differences in partial pressures and the density of the mass flow of water condensate, has been developed. CONCLUSIONS: The existence of water has a negative impact on conditions of a piston engine. The information about the amount of water condensing in a cylinder during the warm-up period stimulates to continue studies in the field of motor oils watering, active acids formation and corrosive wear of surfaces of details.

Diesel-natural gas dual fuel injection strategy effects on engine ignition delay and cylinder pressure evolution

Diesel pilot high-pressure direct injection (HPDI) natural gas technology has been noticed and applied in medium and heavy-duty engines due to its outstanding economy and power performance. However, the combustion of two kinds of fuels will involve more injection parameters, which increases the difficulty of designing injection strategy and calibrating injection parameters. This paper investigates comprehensively the effects of three key engine injection parameters (injection timing, injection duration of the pilot diesel, interval of injection between diesel and natural gas) on the engine ignition delay and cylinder pressure evolution using the experimentation method, which are utilized to guide the design of injection strategy and optimize injection parameters. Results show that the maximum in-cylinder pressure and its position are determined by the injection timing of natural gas, but little affected by the injection parameters of diesel. As the injection timing advances and the duration of diesel injection shortens, the ignition delay increases. To avoid rough combustion in the cylinder, it is necessary to optimize the injection timing, injection interval, and ignition diesel injection duration to ensure that the pressure rise rate does not exceed the threshold.

THE INFLUENCE OF VALVE TIMING ON IN-CYLINDER PRESSURE SPARK IGNITION ENGINES PERFORMANCE CHARACTERISTICS

The performance of the engine depends on many factors. One of the factors is valve timing known to be the timing of opening and closing of valves that has a significant effect on the in-cylinder performance. However, there is less information in the study about valve timing effect on single cylinder engine performances. In this study, the focus is to analyze in-cylinder pressure characteristics on a single piston fuel injection for a spark-ignition engine. This can be done by simulating the effects of valve timing on in-cylinder pressure. The methodology of this project will be simulation-based by using commercial one-dimensional software. The research results are engine performance parameters which are volumetric efficiency, brake torque, brake power, and cylinder pressure in 1000 to 5500 RPM engines. The results show a positive increment in engine performance from the baseline model (CTA240) which is 9.06% for brake power, 2.85% for brake torque, and 13.09% for volumetric efficiency. At low engine speed, it was also found improvement in cylinder pressure when advancing the intake valve timing opening (IVO) by 20 to 25 degrees bTDC. For high speed, the cylinder pressure was found to improve once the retardation of intake valve timing closing (IVC) was done between 40 to 45 degrees aBDC by comparing it with the baseline results. The result highlights the importance of intake valve timing setup by varying the opening and closing of the intake valve to give better output for engine performance.

Preliminary assessment of the potential for rapid combustion of pure ammonia in engine cylinders using the multiple spark ignition strategy

In pursuit of carbon neutrality, the adoption of zero-carbon fuels in internal combustion engines offers a path to zero carbon emissions. Among such fuels, ammonia (NH3) stands out as an effective hydrogen energy carrier with a higher energy density and a more advanced production-storage-transportation lifecycle than hydrogen (H2) fuel, making it a superior alternative. Nevertheless, achieving high combustion efficiencies in engine cylinders requires the use of fuels with fast flame speeds, since the time scales of the combustion event are practically milliseconds. The inherent flame speed of NH3 falls short, typically necessitating augmentation with H2. Yet, the in-situ generation of H2 from NH3 remains constrained, rendering the flame speed of NH3 less competitive against traditional fuels like gasoline and natural gas. To address the dual challenges of slow flame speed of NH3 and the difficulty of generating large amounts of H2 from NH3 onboard, this study evaluates an alternative method of accelerating the ammonia combustion in the engine combustion chamber through the use of multiple spark plugs, which is limited discussed in existing research. Numerical simulations performed in this study show that the application of the multi-spark strategy increases the mass burn rate, advances the combustion phasing, shortens the combustion duration, increases the engine power output, improves the fuel economy, and reduces the unburned ammonia emissions, all of which indicate that rapid combustion of pure ammonia is achieved in the combustion chamber. Moreover, the use of multiple spark points does not lead to a marked increase in nitrogen oxides emissions, thereby ensuring no added stress on exhaust aftertreatment systems. In addition, pure ammonia combustion appears to be very well adapted to this strategy, as evidenced by the avoidance of excessive cylinder pressures and pressure rise rates—a challenge faced by conventional spark ignition engines, given ammonia notably slower flame speed relative to conventional petroleum-based fuels. Overall, all these findings strongly support that the multi-spark ignition system presents a compelling direction for future zero-carbon ammonia engines. However, it is crucial to address design challenges to ensure that the engine head layout provides sufficient cooling, structural robustness, optimal breathing efficiency, and reliable multi-ignition events within the confined space.

Elucidating the mechanism of 1,3-butadiene oxidation with O2: A DFT study

1,3-Butadiene (1,3-C4H6) is a ubiquitous pollutant produced during the combustion of hydrocarbon fuels in engine cylinders. In this study, we delved into the potential energy surface (PES) and rate constant of 1,3-C4H6 employing the density theory (DFT) method and transition state theory (TST). This study comprehensively clarifies the process of O2 oxidation 1,3-C4H6 and its significance on the prediction of combustion dynamic models. Our research reveals that the addition of O2 to the terminal carbon atom of 1,3-C4H6 is the dominant path for addition reactions, leading to the formation of peroxyl radicals. Subsequently, these reactions predominantly yield acrolein and aldehyde groups. Moreover, our data indicates a barrierless and exothermic path for the generation of peroxyl radicals by the O2 addition to the C4H5 radical site. The energy barrier for the dominant path, 1,3-C4H6+H → iC4H5+H2, has been calculated to be 57.6 kJ/mol with a rate constant of 7.89×1010 cm3 mol−1 s−1. This study integrates the kinetic and thermochemical data derived from our targeted reaction system into the updated AramcoMech 3.0. An in-depth analysis reveals the capability of this mechanism to simulate combustion characteristics of 1,3-C4H6, emphasizing its temperature-dependent species profiles. Comparatively, the performance evaluation of the proposed 1,3-C4H6 kinetic mechanism demonstrates its improvement over its predecessor, showing good agreement with experimental results.

Experimental and simulation study on evaporation characteristics of E85 impinging spray under DISI cold-start condition

The direct injection of ethanol-gasoline blended fuel into the engine cylinder near the top dead center (TDC) is evitable to suffer from the wall impingement due to more injection mass required to maintain the same air/fuel ratio with traditional fossil fuels. In this study, the evaporation characteristics of E85 cold-start impinging spray were investigated by experiments and numerical simulation. A constant volume vessel was used to produce the direct-injection spark-ignition (DISI) engine-like conditions. The ultraviolet (UV) – visible (Vis) dual-wavelength laser absorption scattering (LAS) technique was employed to quantitatively measure the individual components evaporation in E85, with the emphasis on the effects of impinging distance, wall temperature and injection pressure on the mixture formation. The results show that although the larger impinging distance rarely influences the evaporation before impingement, it facilitates the E85 evaporation process after impingement due to the better atomization by low boiling point (LBP) components (e.g. ethanol). The effects of cold-start wall temperature on the E85 impinging spray are greatly dependent on the impinging distance. Under the small impinging distance, the ethanol and low boiling point (LBP) components of gasoline evaporate faster after impingement at higher wall temperature, but such effect becomes absent under long impinging distance. Therefore, the smaller impinging distance shows a higher sensitivity to wall temperature. Lower wall temperature leads to a high wall heat transfer, thus potentially extend the evaporation time at the near wall region along the spray axis. At either impingement timing or initial impingement, the LBP component with high latent heat evaporates fast, leading to a decrease of surrounding gas temperature. Increasing injection pressure helps to greatly improve the evaporation of the high boiling point (HBP) component in gasoline under cold-start impingement. The evaporation ratio of E85 increases up to about 18% ∼ 30% than that of E100 at the initial impinging period under cold-start condition.

Influence of hydrogen fraction and injection timing on in-cylinder combustion and emission characteristics of hydrogen-diesel dual-fuel engine

In order to achieve low-carbon, high-efficient and clean combustion for internal combustion engines, hydrogen-diesel dual-fuel combustion mode (HDDF) was conducted on a 4-cylinder common-rail diesel engine. This research investigated the effects of hydrogen substitution ratio (HSR) and diesel injection timing (DIT) on in-cylinder combustion and emission characteristics of HDDF engine at 20% and 40% loads. The results show that with the increase of HSR, the maximum combustion pressure of HDDF engine shows a decreasing trend, and the peak phase gradually advances. The overall trends of COVIMEP and combustion duration increase. The NO, CO2, CO, Soot and HC emissions all decrease, while NOx emissions first decrease and then increase. At 20% load and HSR = 30% conditions, CO2 emission decreases by 14.96% compared to baseline engine. With the advance of DIT, the maximum combustion pressure of HDDF engine increases, the ignition delay and combustion duration become longer, and COVIMEP shows a downward trend. The NO2, NO, CO2 and NOx emissions and BTE increase, while both CO and HC decrease. When the DIT is advanced from −2 °CA ATDC to −10 °CA ATDC, the BTE of HDDF engine increases from 28.8% to 31.3%.

An Analysis of Mechanical and Thermal Stresses, Temperature and Displacement within the Transparent Cylinder and Piston Top of a Small Direct-Injection Spark-Ignition Optical Engine

Two- and three-wheeled vehicles account for a significant portion of the automobile market in several countries worldwide. In order to advance the capabilities of these vehicles, the integration of direct-injection (DI) technology is essential, given its potential benefits such as high thermal efficiency and low engine-out emissions. Direct injection in small-bore engines, however, further complicates the challenges involved (of DI technology) like fuel impingement and mixture inhomogeneity inside the engine cylinder, driving the need for an in-depth exploration of in-cylinder processes. Consequently, the necessity arises to develop a small-bore direct-injection spark-ignition (DISI) optical engine that incorporates a transparent cylinder and piston top. In this scenario, these transparent components are required to endure a combination of intricate loads and boundary conditions, hence the potential to result in failures. This work aims to assess numerically the effects of these loads and boundary conditions on the transparent components and optimize their thicknesses. For this purpose, a computer-aided design model of a small-bore DISI optical engine (displacement volume of 200 cm3) is developed. The mechanical and thermal loads are extracted from the experimental data and validated computational fluid dynamics model of the same engine configuration. A coupled temperature-displacement finite element analysis methodology is developed in ABAQUS/CAE, and simulations are performed under both steady and transient conditions. Temperature and combined stress distributions within the transparent cylinder and piston top are obtained and analyzed to find their optimum thicknesses. Knowing thermal gradients, combined stresses and displacements under actual conditions helped design the small optical engine with an improved factor of safety.

Structure of the Air Flow in the Cylinder of Engines with Inlet Pipelines of Various Configurations

Structure of the Air Flow in the Cylinder of Engines with Inlet Pipelines of Various Configurations

Experimental investigation of fuel consumption and emissions of diesel engine fueled with ternary fuel blends of diesel, biodiesel and bioethanol

Biodiesel and bioethanol are two popular biofuels that commonly are used in combination with diesel and gasoline fuels respectively in diesel engines and gasoline engines. Diesel and biodiesel fuels have similar characteristics. However, they have different characteristics compared to bioethanol. Also high proportions of bioethanol cannot be solved in diesel fuel. Then using bioethanol and diesel fuel blends and the effects on diesel engine performance needs further investigation. Biodiesel as a co-solvent is used in bioethanol and diesel fuel mixtures to increase lubricity and cetane number of the blends. In this study, a 4-stroke, 4-cylinder diesel engine coupled with a dynamometer was used for the investigation of diesel engine emission and fuel consumption. Fuels B10E10D80, B10E15D75, B10E20D70, and D100 were used in this study at different speeds (from 1200 to 2400 rpm with 200 rpm increment) on 50% and 100% engine loads were measured. Here, B, E, and D respectively represent biodiesel, bioethanol, and diesel fuel and numbers indicate the percentage of those fuels. Fuel consumption and emissions (CO, CO2, NOx, and C6H14) were measured. Average changes of emissions of CO, CO2, NO, NO2 and C6H14 on different loads and speeds were decreased respectively by 20–38%, 1–6%, 11–14%, 9%, and 3–24%, respectively The average diesel engine fuel consumption using B10E10D80 and B10E20D70 fuels was only higher by 2% and 3% than that of using pure diesel fuel and with using B10E15D75 fuel it was equal to that of using pure diesel fuel. In conclusion, using ternary fuel blends instead of pure diesel fuel significantly decreases diesel engine emissions for CO, CO2, and NO. Fuel consumption negligibly increased by using ternary fuel blends instead of pure diesel fuel. As a result, ternary fuel blends could be considered as alternatives to diesel fuel.

Performance and emission characteristics of double split injection biodiesel engine with intake air throttling

Most diesel engines typically operate with high excess air in part load. Implementing air intake restriction with exhaust gas recirculation (EGR) could be a viable option for mitigating NOx emission and soot, particularly when utilizing biodiesel, attributing to biodiesel's inherent oxygen content. This study examines the effect of intake air throttle and EGR coupled with split injection strategies on a turbocharged 4-cylinder engine fuelled with B60-POME fuel. A parametric test was conducted to examine the impact of fuel injection pressure, intake air throttling and EGR, followed by Response Surface Methodology (RSM) optimisation. When EGR is implemented with a 45% intake throttle opening, a relatively low EGR rate of 5% is achieved. A study utilising RSM was conducted to optimise the control of air supply and split injection parameters, involved with a total of 6 control variables. The optimum parameter appears at a dwell angle of 12 °CA, SOI timing of −4°ATDC, 40% intake throttle opening, EGR of 6.75%, fuel injection pressure of 800 bar and split injection ratio of 50%. These settings yield prediction emission results that are closely similar to those obtained from the actual confirmation test.

Fuel-air mixing in motored CFR engine at research octane number (RON) relevant condition

This paper presents a three-dimensional (3-D) computational fluid dynamics (CFD) study of a motored cooperative fuel research (CFR) engine at research octane number (RON) relevant condition. The boundary conditions for 3-D simulations were generated with a one-dimensional GT-Power model. For the first time in literature, a carburetor was added to a virtual CFR engine model with 3-D CFD. Therefore, the proposed setup can simulate the fuel and thermal stratifications inside the engine cylinder with realistic detail. The transient simulations in this work were performed within the Reynolds-averaged Navier-Stokes (RANS) framework with a Realizable k-ε turbulence model. Major conclusions from the present work are: (1) The in-cylinder flow of the CFR engine is swirl-dominated due to the existence of the intake valve shroud. (2) There is a significant amount of liquid droplets entering the cylinder during the intake stroke. The maximum instantaneous amount of liquid for 50% PRF 87 (containing 87% iso-octane and 13% n-heptane (v/v)) and 50% ethanol mixture is indicated to be around 26% of total injected fuel mass. (3) The heat of vaporization (HoV) of the fuel is responsible for creating both temperature and charge stratification inside the cylinder.

Effects of Nozzle Diameter and Holes Number on the Performance and Emissions of a Gasoline Direct Injection Engine

The goal of the current study is to estimate how a gasoline direct injection (GDI) engine's performance and emissions are affected by the fuel injector nozzle diameter and hole number of its injectors. A thermodynamic mathematical modelling has been created utilizing a software program written in the MATLAB language to simulate the two-zone combustion process of a four-stroke direct injection engine running on gasoline at (Rotation Engine Speed 3000 revolution per minute (rpm), 40 MPa injection pressure, compression ratio 9.5, and spark timing 145°). The first law of thermodynamics, equation of energy, mass conserving, equation of state, and mass fraction burned were all used in the creation of the software program. The study was carried out at five different nozzle diameters (0.250, 0.350, 0.450, 0.550, and 0.650 mm) and nozzle hole numbers (4,6,8,10,12). The results show that the GDI engine's performance and emissions are significantly influenced by variations in nozzle hole diameter and number. It was shown that engine power, heat transfer, cylinder pressure, and temperature increased with increasing nozzle hole diameter and number of nozzle holes and the maximum value was seen with nozzle hole diameter 0.650 mm and (12) holes. The lowest value for the nozzle hole diameter and number of holes was found to be 0.250 mm and 4 nozzle holes, which resulted in the lowest emissions of carbon monoxide CO and nitrogen monoxide NO. The study was also conducted for different operating conditions (Rotation Engine speed of 1000, 2000, 3000, 4000, 5000 rpm ,35 MPa injection pressure , compression ratio of 11.5 , and spark timing of 140° ) and the same nozzle diameters and nozzle holes number mentioned previously to estimate the maximum values for temperature, pressure, power , heat transfer and emissions . The results of the second part of the study showed that the highest of maximum values of temperature, pressure, and emissions were at of 1000 rpm, a nozzle diameter of 0.650 mm, and (12) holes. The highest values for maximum power at 4000 rpm, a nozzle diameter of 0.650 mm and (12) holes, while the highest maximum values for heat transfer are at 5000 rpm, a diameter of 0.65mm and (12) holes.

A Study on the Uncertainty Minimization of Honing Process for Diesel Engine Cylinder Liner Bore Manufacturing

A Study on the Uncertainty Minimization of Honing Process for Diesel Engine Cylinder Liner Bore Manufacturing

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.

A Mathematical Model for a Hybrid Ignition System

In the operation of a car's ignition system, the primary ignition coil is responsible for generating a high voltage that typically ranges from around 100V to 300V. However, this self-induced electromotive force (emf) can lead to certain negative effects such as switch breakdown, inductive noise, and secondary voltage drop. This article introduces a novel hybrid ignition system designed for a 4-cylinder engine. This innovative system is a combination of capacitive discharge ignition system (CDI) and induction discharge ignition (IDI) system. The excess electromagnetic force energy (emf) generated during the induction ignition stage will be used in the capacitive ignition. Thereby contributing to limiting the negative effects as mentioned. Forming and solving the mathematical model for the hybrid ignition system mentioned above enables us to analyze the transient responses of the primary current (i1) and primary voltage (V1). These instantaneous responses are crucial in understanding the behavior of the composite ignition circuit and calculating key parameters such as ignition energy during the inductive and capacitive ignition stages, as well as the magnitude of the maximum secondary voltage (V2m). Furthermore, the article also presents experimental results from the hybrid ignition system to complement the theoretical analysis.

Experimental investigation of hydrogen combustion in a single cylinder PFI engine

The simultaneous reduction of Green-House Gases (GHG) and criteria pollutants is the main target of current Internal Combustion Engines (ICE) development. Hydrogen (H2) fueling is one of the best options available in both regards, as it does not emit tailpipe CO2 as well as significantly abates all criteria pollutants already at engine-out level. However, optimizing hydrogen combustion in order to exploit the fuel proprieties at best is a challenging task due to the very particular properties of the fuel. In fact, H2 combustion in ICE promotes a very clean, fast and complete combustion process, with extremely low HC, CO, and PM engine-out emissions stemming only from lubricant oil. The usage of lean-boosted and EGR-diluted combustion strategies can significantly contribute to raise the brake thermal efficiency and lower the NOx emission to extremely low levels. To this end, the Authors tested a 0.5 L single cylinder engine featuring an optimized PFI layout and dedicated piston bowl profile for a retrofitted Diesel operating as H2 monofuel, in SI mode. In this paper, the authors discuss the effect of the main engine parameters, extensively investigated by means of Design of Experiments (DoE) techniques, as well as the effect of dilution and EGR to promote clean and efficient hydrogen combustion, in order to recommend the most effective practices.