Fuel Injection System Research Articles

Investigation of Factors Influencing Solenoid Valve Speed Response Characteristics of the Common Rail Injector

The dynamic injection characteristics of high-pressure common rail fuel injection systems are determined by the speed response performance of the solenoid valve. A simulation model has been established for investigating the influence mechanism and change law of characteristic parameters on speed response characteristics of the solenoid valve. The speed response characteristics of the solenoid valve, including the average opening speed, the average closing speed, the maximum opening speed, and the maximum closing speed, caused by the changes of characteristic parameters such as pre-tightening force of the solenoid valve spring, mass of the solenoid valve moving parts, diameter of the outflow orifice, diameter of the inflow orifice, diameter of the control piston, and pressure in the common rail, have been studied. The correlation analysis of the influence factors is carried out by using the experimental design method based on the response surface model, and the correlation coefficients between each factor and the speed response characteristics of the solenoid valve are obtained. The results show that both single factors and interaction factors of the parameters are correlated with the speed response characteristics of the solenoid valve. The results of this paper can provide a theoretical reference for the design and optimization of the high-pressure common rail injector.

Optimization Strategy to Reduce Unplanned Low Power Engine Breakdowns on PC-2000 Units at PT Antareja Mahada Makmur

Low-power machine breakdowns that occur unplanned (unscheduled) on the PC-2000 unit are one of the main obstacles in maintaining operational efficiency in the workshop area of PT Antareja Mahada Makmur Jobsite Mifa Bersaudara. This study aims to identify the main causes and design optimization strategies to reduce the frequency of these events. The research methodology included analysis of historical damage data, technical inspection of the affected machine components, and evaluation of the quality of the fuel used. Based on the analysis, it was found that the use of B35 fuel (35% biodiesel) is one of the significant factors affecting engine performance, especially in the combustion system and fuel injection components. The implementation of preventive maintenance-based strategies, including increased frequency of fuel injection system inspections, replacement of vulnerable components, and use of fuel additives to improve combustion efficiency, reduced the frequency of breakdowns by 40% within three months of implementation. The results of this study emphasize the importance of mitigating the impact of B35 fuel use on engine performance through a planned maintenance approach. Recommendations include developing technical guidelines specific to biodiesel fuel use and training technicians to support more reliable operational sustainability.

A Novel Friction Mean Effective Pressure Model for a Heavy-Duty Diesel Engine by Neural Network and Its Applications to Heat Release Rate Profile Optimization

<div>The prediction of friction mean effective pressure (FMEP) is important when engine performance is estimated in the model-based development process. The Chen–Flynn model as a function of the maximum in-cylinder pressure (P<sub>max</sub>) and mean piston speed (C<sub>m</sub>) is often used to predict FMEP because of its simplicity to utilize; however, this study inferred from the results of multiple regression analysis between FMEP and factors related to combustion phase and rate of heat release profile (ROHR) that the Chen–Flynn model may be difficult to accurately estimate FMEP in a modern diesel engine with common rail fuel injection system, which allows the control of fuel injection pressure (P<sub>inj</sub>) and combustion phase. In this study, a neural network with machine learning was applied to predict FMEP based on the expectation that the ROHR profile, which allows the reduction of FMEP may be possible to be found. 7666 points experimental results that include FMEP and combustion parameters in the heavy-duty single-cylinder diesel engine were utilized as training and validation data for machine learning. The pre-trained neural network prediction model for FMEP can predict the tendency of FMEP better than the Chen–Flynn model when start of combustion (SOC) and P<sub>inj</sub> were varied. The error between the predicted FMEP results by the pre-trained neural network and the experimental results of FMEP were within 4% of the experimental results when SOC was advanced from top dead center to −7 deg. ATDC. Whereas, the predicted FMEP by Chen-–Flynn model had a maximum error of 15% compare to the experimental results. Furthermore, the predicted FMEP by Chen–Flynn model had a maximum error of 9% compare to the experimental results when P<sub>inj</sub> was varied from 120 MPa to 200 MPa, whereas the error between the predicted FMEP results by the pre-trained neural network and the experimental results of FMEP were within 4% of the experimental results. The pre-trained neural network model was confirmed to be predictive better than the Chen–Flynn under the conditions that the combustion phase and P<sub>inj</sub> are changing. In addition, the parameter study using the pre-trained neural network prediction model for FMEP and a one-dimensional engine performance simulation tool was conducted to find the ideal ROHR profile that improve brake thermal efficiency (BTE). The result of parameter study suggests that the optimum ROHR profile to improve BTE under the same conditions of P<sub>max</sub> and the degree of constant volume combustion is to shorten combustion duration and to retard the peak of ROHR away from top dead center.</div>

Diagnosing the Process of Forming Biofuel Combustion Mixtures in Diesel Engines by a Program to Compute Spray Volume

A diesel engine's injection and combustion mixture formation process are essential; it determines the engine's economic, technical, and environmental criteria. When the engine uses biofuel, fuel parameters such as viscosity, density, and surface tension affect the above process. Each engine using a specific fuel type will have to adjust injection parameters such as injection pressure and timing to ensure the injection process and formation of a homogeneous air-fuel mixture. Therefore, through the spray structure, it is possible to diagnose the process of combustion mixture formation, thereby making adjustments to the fuel injection system that will improve engine performance and reduce emissions of toxic exhaust gases. In this study, the article presents the content of building a program to compute spray volume using Matlab software. Through the spray volume, quickly diagnose the process of forming the biofuel-air mixture in the diesel engine combustion chamber, thereby determining the appropriate fuel injection system adjustment. Results of simulation and experimental research on 4CHE Yanmar engines installed on fishing vessels with fuel types DO, B5, B10, and B15 show that the B15 fuel mixture when used for the engine needs to be increased injection pressure is about 10% higher than DO fuel injection pressure.

Hydrogen-enriched lean-burn strategy for gasoline direct injection engine utilizing non-thermal plasma fuel reformer

The objective of the task is to sustain and enhance combustion stability at the extension of lean limit of customized Gasoline Direct Injection (GDI) Engine with the supplementation of Hydrogen Rich Gas (HRG) and hydrogen. HRG was supplemented from the on board non thermal Plasma Fuel Reformer (PFR) and hydrogen from the bottled storage through integrated gas control device to the GDI engine. The gas constituents of PFR was theoretically arrived from thermodynamic combustion equations to determine energy based fuel proportion in the ternary fuel injection system. Binary fuel mixture of HRG and hydrogen 10%, 18%, 30% of energy based proportion with gasoline were experimented on test engine. The impact of discrete and binary fuel mixture with gasoline at Stoichiometric Fuel Air ratio was observed and extended baseline equivalence ratio until misfire of the ternary fuel air mixture was occurred. Apart from significant improvement of performance the addition gaseous mixture increases oxides of nitrogen marginally. From the perspective it was noticed that combustion products exhibit better heat transfer out of cylinder at the Maximum Brake Torque Timing (MBT). This was attributed to higher combustion temperatures and improved quenching distances which in turn increased thermal efficiency against the specified equivalence ratio. However retarding MBT suppresses oxides of nitrogen and continued to increase thermal efficiency. It was concluded that lightning fast burn speed, fine fuel atomization of 10% mass based hydrogen and HRG 18%combination fraction increase engine thermal efficiency while decreasing NOx emission and alleviate HC trade-off characteristics.

Matching and calibration of FSC single cylinder engine

Abstract To participate in Formula Student of China, the CRF450X single-cylinder engine is selected as the power source. The researchers used the MOTEC-M400 model ECU as an electric control unit to upgrade the electronic control fuel injection system. To restore the original power of the engine, you can create a crankshaft signal disk, install a camshaft position sensor, add a pressure cavity intake pipe, and include an oxygen sensor. Then, we optimize the calibration by adjusting the basic injection pulse width and ignition angle to obtain the power and torque characteristic curves of the engine. Through the upgrade of the electric injection system, the oil injection time and ignition time are accurately controlled, achieving the purpose of reducing fuel consumption and improving the performance of the car.

Performance study of an innovative dual injection mode injector for marine low-speed dual-fuel engine

Marine low-speed dual-fuel engines typically have two sets of fuel injection system, main-injection and micro-injection. In order to make the fuel injection system of marine low-speed dual-fuel engine compact in structure and flexible in injection control, an innovative dual injection mode injector (DIMI) which can achieve both the functions of main-injection and micro-injection was proposed. The switching between main-injection and micro-injection mode of the injector is achieved through the collaborative control of dual solenoid valves. Based on the constructed AMESim model, the injection quantity characteristic and hydraulic efficiency of the DIMI were investigated under different working conditions and injection modes. The results show that, when the DIMI in main-injection mode achieves injection quantity characteristic similar to those of a traditional electronically controlled injector (TECI), the electromagnetic forces of solenoid valves of the DIMI are less required to 80% of that of the TECI, and the fuel return quantity and hydraulic efficiency of the DIMI are comparable to those of the TECI under the same working conditions. By changing the minimum limit height of the needle of the DIMI under micro-injection mode, different ranges of micro-injection quantity could be designed according to the requirements of the engine, and the control accuracy of injection pulse width (IPW) on micro-injection quantity is higher than on main-injection quantity. Both the hydraulic efficiency of the DIMI under main-injection and micro-injection mode increase with the rail pressure and IPW in the small IPW range, then gradually tend to be saturated with the increase of IPW. As the minimum limit height of the needle increases, the injection quantity and hydraulic efficiency of the DIMI under micro-injection mode increases overall, however, the saturation values of the hydraulic efficiency in micro-injection mode under different needle minimum limit heights are still smaller than those in main-injection mode.

An experimental investigation of the combustion process and the injection strategy of a heavy-duty diesel engine equipped with a common rail fuel injection system

Heavy-duty (HD) diesel vehicles exert significant environmental impact, especially in the case of nitrogen oxides (NOx) and soot, despite representing a relatively small portion of the overall vehicle population. Modern HD diesel engines employ multi-pulse fuel injection strategies to optimize the combustion process to achieve a better compromise between fuel economy and tail-pipe emissions, especially NOx. As such, improving our understanding of the combustion process and the characteristics of modern HD diesel engines operating under various fuel injection strategies is imperative. This research investigates the fuel injection strategy, combustion process and exhaust emissions of a Navistar 2021 MY HD E39 diesel engine. The impact of engine speed, load and injection strategy on engine performance, the combustion process, engine-out NOx and SCR efficiency is experimentally investigated. The relationships between these parameters provide a better understanding of the influence of the injection strategies on the combustion process, fuel economy and exhaust emissions. Fuel was injected into the cylinder with up to four injection pulses, including up to two pilot injections followed by one main injection pulse and one post injection pulse. The heat release process is featured with three peaks. The first and second peaks are associated with the combustion of fuel injected during the pilot and main fuel injection pulses, respectively. However, the third peak observed at medium to high load is associated with the combustion of fuel injected during post injection process. In comparison to its predecessors, the third peak observed at low load was associated with the diffusion combustion of fuel injected during the main injection pulse. The combustion process, which occurred at medium to high loads, was optimized to achieve high engine thermal efficiency, with the peak cylinder pressure held within the allowed limit while the exhaust temperature was high to achieve acceptable SCR efficiency. In comparison, the combustion phasing at low load was dramatically retarded to increase the exhaust temperature with the aim of maintaining SCR efficiency. The strategies for achieving the ideal compromise between fuel economy and tailpipe emissions are discussed and presented herein.

REAL-TIME PARAMETRIC DIAGNOSTICS OF MARINE DIESEL ENGINES

Using modern high-performance microcontrollers with wireless interfaces, built-in ADC and low overall consumption, it is possible to develop a portable real-time parametric diagnostic system for marine engines. The system is based on the use of modern Android/iOS gadgets that receive information from sensors via Bluetooth and then make the necessary calculations and display charts and data in real time. The system being developed uses a combination of a gas pressure sensor in the working cylinder and a vibroacoustic sensor, which expands the diagnostic capabilities of marine diesel engines under operating conditions. This solution makes it possible to diagnose the fuel injection system, the valves control mechanism, as well as some other engine systems. In order to develop a portable diagnostic system for marine diesel engines, it is first necessary to solve the problem of analytically determining TDC, since such a system does not involve the use of special sensors for this. Parameters of irregular engine operation are considered, which can be calculated in real time using time diagrams of pressure and vibration. Methods for expressly assessing the stability of the functioning of the main engine systems by monitoring and analyzing a number of successive operating cycles are considered. To assess the unevenness of engine operation, a dispersion estimate of deviations of the main parameters is used. For a comprehensive assessment of engine stability in real time, the CII (cycle’s irregularity index) criterion is proposed. The assessment of fuel injection irregularity in the engine cylinder can be carried out by analyzing the phase fronts of the vibration signal of the injector. Coefficients for assessing the irregularity of fuel injection and gas distribution valves timing are also proposed, using dispersion analysis of vibrograms fronts. The data processing methods proposed in the article will make it possible to analyze the stability of operating cycles, as well as to perform optimal tuning of engine systems and monitor the results during operation.

SCIENTIFIC-TECHNICAL AND PRODUCTION POTENTIAL OF UKRAINE FOR THE PRODUCTION OF SCIENTIFIC PRODUCTS OF DIESEL CONSTRUCTION

In this work, an attempt is made to provide an assessment of the prospects for the development of automotive diesel engineering in Ukraine, the availability and preservation of scientific, technical and production potential for the continuation of the production of knowledge-intensive products of this domestic sub-industry in modern conditions. According to the authors, the manufacturers of vehicles in Ukraine quickly found the support of the State regarding the inclusion of the relatively most complex structural units of the car design - the engine and the chassis - in the list of imported components, since the manufacture of these parts requires high-tech processes that ensure the manufacture of low-quality parts. Other personal opinions of the authors have been expressed regarding the reasons for the absence of energy sources that ensure the economic development of the country and are considered science-intensive products in the modern domestic automotive industry. According to the results of the research, it was established that the list of developments of the domestic automotive diesel industry in recent years extends from the two-cylinder diesel engine of the ZIM-800D four-wheeled motorcycle, which was proven to be introduced into the series, and the ZIM-1901 and ZIM-1902 microcars, to the design documentation of the modern six-cylinder diesel engine 6DTNA2 with a four-valve cylinder head and electronic fuel injection system. As an example of the capacity of the domestic production potential, the production technology of the cylinder head of a four-cylinder diesel engine 4ChN 8.8/8.2 was worked out with the involvement of available production resources and the use of imported components. This approach makes it possible to significantly reduce the time for the manufacture and preparation of the production of structural elements of the domestically produced engine, which is a representative of the "Slobozhansky diesel" power series.

Methods of Real-Time Parametric Diagnostics for Marine Diesel Engines

Abstract Using modern high-performance microcontrollers with wireless interfaces, built-in ADCs and low overall consumption, we develop a portable, real-time parametric diagnostic system for marine engines. The system is based on the use of modern Android/iOS gadgets that receive information from sensors via Bluetooth and then carry out the necessary calculations and display charts and data in real time. The system developed here uses a combination of a gas pressure sensor in the working cylinder and a vibroacoustic sensor, which expands the diagnostic capabilities of marine diesel engines under operating conditions. This solution allows for diagnosis of the fuel injection system, the valve train mechanism, and several other engine systems. In order to develop a portable diagnostic system for marine diesel engines, it is first necessary to solve the problem of analytically determining top dead centre (TDC), since such a system does not use special sensors for this. An algorithm for determining TDC is proposed here, based on an analysis of the measured pressure diagram rather than its derivative, which minimises the influence of digital and analogue noise. Our algorithm for determining TDC and subsequent data synchronisation is applicable in the absence of information about the actual compression ratio in the cylinder, which is a typical scenario for modern engines with variable valve timing. The algorithm also works under conditions of only approximate data on the charge air pressure, which are refined during the iteration process. A formula is proposed for determining the initial TDC position. Parameters for irregular operation of the engine are considered, and can be calculated in real time using time diagrams of pressure and vibration. Methods for expressly assessing the stability of the functioning of the main engine systems by monitoring and analysing a number of successive operating cycles are considered. To assess the unevenness of operation of the engine, a dispersion estimate of the deviations in the main parameters is used. To enable a comprehensive assessment of the engine stability in real time, the CII (cycle irregularity index) criterion is developed. The data processing methods described in this article provide an accurate estimate of the indicated power, due to the precise determination of TDC, thereby enabling an analysis of the stability of the operating cycles, optimal tuning of the engine systems, and monitoring of the results during operation.

Study on precise fuel injection under multiple injections of high pressure common rail system based on deep learning

The fluctuation of fuel injection quantity under multiple injections of high pressure common rail system leads to a decline in engine economy and emission performance, the precise injection control is the key problem in current research. In this study, a deep learning data-driven model of injection quantity under multiple injections was established based on generalized regression neural network (GRNN), and the particle swarm optimization (PSO) was introduced to optimize the smoothing factor in the model, thereby improving its prediction accuracy. An injection quantity correction method based on the data-driven model was proposed and applied to actual common rail fuel injection system for experimental verification. The results demonstrate that the proposed data-driven model has excellent prediction performance and generalization ability for the predicted main injection quantity with mean absolute percentage error of 1.10 % and determination coefficient of 0.997. Through the experimental verification of the correction method under 144 groups of operating conditions, it was observed that the maximum deviation of main injection quantity decreased from −25.83～17.91 mm3 to −9.81～7.64 mm3, and the maximum absolute deviation reduced by 62.02 %. The precise of injection control under multiple injections is improved.

Enhancing fuel injection system reliability through Weibull family functions analysis

Enhancing fuel injection system reliability through Weibull family functions analysis

Study on partial oxidation phenomena of post-injection fuel in diesel engines

In diesel engines, post fuel is injected in the expansion stroke, oxidized by the diesel oxidation catalysts and the high temperature gas re-generates the diesel particulate filters. However, it is empirically known that the post fuel at advanced injection timing is partially oxidized in the cylinder due to the high temperature-pressure conditions and it is a cause of the reduction of fuel consumption. The purpose of this research is to analyze post-injection fuel behaviors in cylinder and investigate the optimum fuel injections that maximize the unburnt hydrocarbons to the diesel oxidation catalysts. The engine employed in this research is a turbo charged 2.0 L four-cylinder DI diesel engine with two fuel injection systems to change the heterogeneity of air-fuel mixture and temperature distributions in cylinder; n-hexane is injected in the intake manifold to produce the homogeneous air-fuel mixture and diesel fuel is directly injected into the cylinder. The partial oxidation ratio of post fuel and the fuel loss mainly by fuel adhesion was calculated by injected fuel quantity, air quantity, and emission data. The 3D-CFD software was introduced to analyze the partial oxidation of post fuel and flow in the cylinder. The heterogeneity of burned gas mixture of post injection atmosphere and the post-injection timings were the parameters of engine tests and 3D-CFD simulations. The results suggest that the heterogeneity of equivalence ratio and the non-uniformity of gas temperature inside the cylinder at the start of post injection affect the partial oxidation of post-injection fuel. The more homogeneous these conditions are, the better the suppression of partial oxidation of post-injection fuel and the avoidance of fuel adhesion to the cylinder wall can be achieved.

Spray characteristics of elliptical orifice spray in diesel engine under air movement conditions

The development of high-quality mixture is a critical requirement for achieving high-efficiency and low-emission diesel engines, and fuel injection system performance improvement and in-cylinder airflow organization are crucial ways for achieving high-quality mixture. The elliptical nozzle is used as the research object in this research, and numerical simulation is utilized to investigate the effect of different airflow speeds and directions on the atomization characteristics of the elliptical nozzle jet, in order to provide a theoretical basis for the engineering application of the elliptical nozzle in diesel engines. The results show that under the same airflow conditions, the vertical penetration distance of the spray decreases while the horizontal penetration distance increases with the use of elliptical orifices, the surface wave perturbation on the windward side is more violent, and reduce spray field the Sauter Mean Diameter (SMD). The spray projected area grew by 13.5%, the spray SMD dropped by 14.8%, and the vertical penetration distance of the spray with elliptical orifices fell by 18% with an increase in airflow velocity from 0 to 20 m/s. When the airflow direction and the spray direction were at a 90° angle and the SMD was lower than that of the circular orifice by 12.9%. The angle between the airflow direction and the short axis of the elliptical orifice was 30°when the spray projection area was larger, the perturbation of the spray body was more intense, and the surface wave amplitude was larger.

Cavitation Phenomenon and Spray Atomization in Different Types of Diesel Engine Nozzles: A Systematic Review

<div>The high-pressure common rail fuel injection system for diesel engines is one of the core technologies that need to be addressed in the automobile industry. The control of the internal flow in multi-hole injector nozzles is the key to achieve accurate control of the fuel injection and spray process. There are various types of research on cavitation phenomena currently conducted on various types of test benches, but there is no conclusive discussion. Therefore, it is to summarize these studies in order to identify the highlights of existing studies and point out their shortcomings. This article compares and analyzes the developing patterns of cavitation phenomena on four test benches through literature review and has obtained rich research data on these four types of nozzles, but they still have their own shortcomings at the same time, even with numerical simulation. Based on this, the article has conducted a detailed and critical discussion on the current research situation and completed a summary. Specifically, it mainly involves four geometry parameters, two dynamic factors, and three fuel physical property parameters. The discussion conducted can contribute to the future development of cavitation models, further improving the energy-saving and -reducing emission reduction of diesel engines.</div>

Valuating the impact of biodiesel B10, B20 on lubricating oil in a commonrail diesel engine

Biodiesel typically has a higher boiling point, viscosity, density, and surface tension compared to traditional diesel. This can result in larger fuel droplets and potentially increased penetration into the engine crankcase. This article presents experimental findings on the impact of using biodiesel blends B10 and B20 (with B100 made from palm oil) on key lubricating oil properties in a D4CB 2.5TCI-A diesel engine equipped with a CommonRail fuel injection system installed in a Hyundai Starex vehicle. The evaluation is based on comparing lubricating oil properties when using different fuels: diesel (B0), biodiesel B10, and biodiesel B20 over a 3000 km driving cycle. Results indicate that the effects of B10 and B20 on lubricating oil properties are similar to those of conventional diesel B0.

Теоретические исследования процесса топливоподачи газового двигателя

This article is devoted to theoretical studies of the fuel supply process of a gas engine. It examines the main aspects of the functioning of the fuel supply system, the influence of fuel supply parameters on the efficiency of the engine, as well as problems and solutions. The authors analyze various theoretical models, describe the basic principles of fuel injection systems and discuss current trends in the development of this field. The article is intended for specialists in the field of automotive, mechanics and thermal engineering, as well as for anyone interested in modern technologies in the field of motor transport. Theoretical studies of the gas engine fuel supply process are of great importance in the modern automotive industry. The efficiency of a gas engine depends directly on the correct selection of fuel supply parameters, which makes this topic relevant for research and development. The article analyzes in detail various aspects of the fuel supply process, such as fuel dosing, spraying, system pressure, as well as interaction with other engine systems So, the presented article is a valuable contribution to the field of gas engine fuel supply research and can be useful both for specialists involved in the development of gas engines and for a wide range of readers interested in modern technologies and innovations in the field of automotive technology. Keywords: GAS ENGINE, FUEL SUPPLY, FUEL INJECTION SYSTEM, AGROENGINEERING, INNOVATIONS IN THE FUEL SUPPLY SYSTEM, AGROTECHNICS, FUEL SUPPLY PARAMETERS

Study on fuel injection stability improvement in marine low-speed dual-fuel engines

Pressure waves within the fuel injection system exert a significant influence on the fuel injection process. This study investigated the impact of pressure waves on injection quantity stability. To quantify the influence of pressure waves on injection quantity stability, the relative standard deviation (RSD) was introduced as a metric. Through computational analysis under various operating conditions, the following results were obtained: when the target rail pressure is constant, the RSD tends to diminish as the injection quantity increases. The elevated RSDs observed during small injection quantities are predominantly attributed to the short power-on period of the solenoid valve. Subsequently, parameter optimization and structural improvements were carried out on the injector to address this problem. The results indicate that optimizing structural parameters alone has a limited effect on reducing RSD. However, by adding a block in the control chamber above the needle to improve the structural layout of the injector, the maximum RSD has been reduced from 21.08% to 4.58% under the action of pressure waves caused by fuel injection, and from 29.24% to 6.67% under the action of given random high-frequency pressure waves. The proposed improvement idea for existing injectors enhances injection stability across the entire operating condition range, thereby improving fuel utilization efficiency.

Shape/penetration analysis and comparisons of isolated spray plumes in a multi-hole Diesel spray

Fuel injection systems significantly impact the combustion process and play a key role in reducing harmful exhaust emissions in internal combustion engines. For dual-fuel (DF) engines operating in gas mode, ignition of the main fuel is typically controlled by directly injected liquid pilot fuel. Liquid pilot fuel’s initial penetration and total mass considerably impact exhaust emissions and combustion stability. We investigated the spray morphology of a multi-hole diesel fuel injector within a constant-volume spray chamber using high-speed shadowgraphy and Mie-scattering measurements. Two methodologies were employed. The first one utilized a nozzle equipped with a thimble structure to isolate a single plume. The second methodology known as plume-blocking, involved sealing the orifices of the multi-hole nozzle to generate a single-spray plume. Our findings revealed that the plume-blocking approach demonstrated greater penetration than the thimble-equipped nozzle. The rapid penetration of this method may restrict its applicability to single-spray studies. Sprays generated from this partially sealed nozzle exhibited noticeable disparities compared to an unblocked nozzle, whereas a nozzle equipped with a thimble produced similar outcomes to the standard nozzle. The orifices when sealed, modify the flow distribution within the sac volume, which consequently affects the spray characteristics. In summary, this research provides insights into the impacts of various plume isolation methods on spray morphology, thereby enhancing the understanding of spray behaviour in transient conditions by comparing plume variations and disturbances under various fuel pressure and ambient conditions.