Engine Cylinder Research Articles

Exploring the combustion, emission and performance of n-Butanol with Deccan hemp oil methyl ester on dual fuel diesel engine.

This experiment investigated the feasibility of using n-butanol with Deccan hemp oil methyl ester derived from Hibiscus cannabinus. Deccan hemp oil, from warm countries like India is an eco-friendly alternative energy source since it is reusable and easy to locate. The Acetone-Butanol-Ethanol (ABE) process made the n-butanol. Further, 60% Deccan hemp oil methyl ester and 40% diesel were mixed and injected directly into the engine's cylinders. The engine's performance was evaluated by adding varying quantities of n-butanol (10%, 20%, or 30%) to the intake pipe at various intervals throughout the experiment. The results showed that using pure Deccan hemp oil or its methyl ester was much better for the engine's performance than regular diesel fuel. This was compared to how well the engine worked when diesel was used. However, the engine ran much better when fed a mix of 60% Deccan hemp oil methyl ester and 40% diesel (B60). Even though it couldn't compete with diesel engines in speed, this was still the case. The engine was running in dual fuel mode when n-butanol was added to the mixture. This made the carbon monoxide, unburned hydrocarbons, and smoke outputs go down. All of these decreases happened without making the engine less able to work. NOx emissions from the B60Bu10 (10% n-butanol share), B60Bu20, and B60Bu30 dual fuel combinations went up by 2.65%, 6%, and 8.9%, respectively, at full load, while smoke emissions went down by 18.33%, 23.75%, and 30.83%, in that order. The study's results show that adding Deccan hemp oil methyl ester to diesel fuel and injecting n-butanol into a dual-fuel diesel engine could help lower emissions without affecting the engine's performance.

Improving heat transfer in an air-cooled engine by redesigning the fins

Heat transfer modelling and simulation were carried out in a single-cylinder, four-stroke, air-cooled engine to evaluate the heat transfer rate of the engine block. The modelling studies of cylinders with different numbers of fins and different geometry were performed using the SolidWorks computer platform. The tested components were made of 6063-T6 aluminium alloy castings. The simulation concerned different numbers of fins as well as changing the geometry of fins with circular and rectangular perforations. The results of the studies showed the possibility of improving the power to mass ratio for cylinder efficiency and heat transfer rate. It was shown that a large number of fins leads to an increased heat transfer rate, but it affects the overall engine efficiency due to the increase in the total engine mass. Circular perforation is a better design solution than rectangular perforated fins with the same cross-section. Circular perforation provides a lower engine cylinder mass and gives more than 4 % better heat transfer rate. The perforation size was tested using circular perforations with a diameter of 7.14 mm, 8.5 mm and 10 mm. With a 7.14 mm diameter perforation the heat transfer rate increases slightly compared to the other tested ones, while a 10 mm diameter perforation provides the best mass reduction.

Synthesis of novel biodegradable silica nanoparticles to improve performance and reduce the emission of CRDI engine fueled with hydrogen-enriched biodiesel blend

Currently, energy poses the most formidable problem globally. Biodiesel has emerged as a viable option for in-depth investigation due to its renewable nature, biodegradability, and reduced emissions. Biodiesel offers potential threats, including low combustion efficiency and high viscosity, which can be managed by enriching hydrogen and fuel additives. Using biocompatible nanoparticles can significantly mitigate the detrimental outcome of metal-enriched nanoparticles on living species. The current study synthesized novel biodegradable silica nanoparticles using waste incense stick ash using a calcination process. The silica nanoparticles were examined using several approaches such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX). The EDX analysis confirms the synthesized nanoparticles contain silicon (41.91%), oxygen (70.23%), and a small percentage of other elements like potassium (0.43%) and calcium (0.23%). The various concentrations (50, 75, 100, 125, and 150 ppm) of silica nanoparticles were dispersed into B20 (diesel with 20% biodiesel) using a probe sonicator. Hydrogen is supplied to the engine cylinder through the intake manifold, maintaining a constant flow rate of 10 lpm. The finding indicated that the brake thermal efficiency (BTE) improves by 15.58% for hydrogen-enriched B20 fuel blend and 100 ppm nanoparticles (B20HN100). The B20HN100 fuel sample contributes to a significant reduction in harmful emissions.

The Role of Thermal Analysis in Engine Fin Design: Insights and Perspectives

Objective: The study aims to address the significance of fins in enhancing the heat transfer rate of engine cylinders and highlight their applications and advancements in various fields. Methods: Thermal analysis of fins using ANSYS Workbench is an invaluable tool for engineers and researchers in determining and optimizing the heat transfer characteristics of finned structures. ANSYS Workbench provides a comprehensive platform for evaluating the performance of fins in various applications using simulations of computational fluid dynamics (CFD) and finite element analysis (FEA). With ANSYS Workbench, it is possible to assess the thermal behaviour of fins under a variety of conditions, such as variable boundary conditions and thermal loads. Some significant recent patents on Engine fin are also discussed in this review article. Results: Fins are designed to maximize contact with the surrounding air or coolant, thereby facilitating engine heat transfer to the surrounding environment. Engineers can enhance heat dissipation capabilities by considering parameters such as fin geometry, density, material selection, and manufacturing techniques while minimizing associated drawbacks. Conclusion: The numerous applications of fins highlighted in this review article will encourage researchers to find novel strategies to improve heat transfer by employing fins for use in a variety of sectors.

ШЛИФОВАНИЕ ПОВЕРХНОСТИ ВОССТАНОВЛЕННЫХ ПОРОШКОВЫМИ ТРУДНООБРАБАТЫВАЕМЫМИ МАТЕРИАЛАМИ

The article discusses the use of impregnated abrasive wheels for grinding the surface of recovered hard-to-process powder materials. The paper investigates the formation of a rough surface during internal grinding of cylinders of marine engines after restoration to their original dimensions, with powder materials of grades PG-CP2, PG-10H-0.2 containing nickel, chromium, iron and other hard-to-work metals, which during the restoration process create a special protective metal layer on the surface of the cylinders, the processing of which is very difficult It's difficult. Therefore, the grinding of the internal surfaces of the restored cylinders of marine engines is a complex technological process that proceeds in strict compliance with all technological operations, in stages. According to the results of the study, the influence of the rotation speed of the workpiece on the roughness of the inner surface of the sleeve, accompanied by grinding with impregnated grinding wheels, was revealed. It has been experimentally confirmed that when treated with impregnated abrasive wheels, the roughness of the polished surface decreases by about 1.5-1.8 times.

A novel design optimization framework to sustain remanufacturability

The ever-increasing global carbon emissions have urged the need for environmentally conscious/sustainable product design, for which the design for remanufacturing (DfRem) is one potential approach. DfRem targets at designing products that have multiple life cycles, thus significantly reducing raw material usage, energy consumption, and carbon emissions. In this paper, we develop a three-stage framework that consists of (1) systematic design space exploration and a multi-objective optimization formulation to minimize the likelihood of failure causes (such as fatigue and wear) and environmental footprint, (2) topology optimization to further reduce material usage without significantly affecting the load-carrying capability of the product, and (3) post-topology optimization design verification to ensure the proposed design satisfies all design constraints. The environmental impact can be assessed at varying comprehensiveness levels (e.g., design and manufacturing phase, use phase) and in terms of carbon or GHG emission, energy use, and waste generation. Because the novel design framework predominantly adjusted the geometry, we focused on mass-based change and energy savings due to sustained remanufacturability. The multi-objective optimization formulation in the first step results in a Pareto optimal set of possible design solutions that the designer can use for the second step. We demonstrate the utility of this framework through a case study of an engine cylinder head subjected to thermo-mechanical loads, where we find that about 5% of the product mass can be conserved with only about a 3% increase in surface area that has a fatigue life less than 10,000 cycles.

A comprehensive propulsion system analysis: an integrated approach utilising engine simulation and free-running model experiments

Regulations concerning the environmental impact and energy efficiency of ships are becoming increasingly stringent. To meet these demanding criteria, new technologies are actively being developed to achieve emission reductions while maintaining efficient fuel energy conversion into propulsion power. However, the propulsion system behaviour in a dynamic environment of the actual sea is highly nonlinear and complex, and a profound understanding of the mutual interactions is still lacking. This paper proposes an integrated approach for comprehensive propulsion system analysis. The key feature of this technique is the utilisation of an intelligent propeller drive controlled by a marine diesel engine simulator (MDES) to drive the free-running model of a ship, providing real-like behaviour of the engine model in real-time in response to actual measured values. The core of the MDES consists of a continuous cycle-mean value dynamic engine model supplemented with a detailed combustion cycle evaluation. The developed fast calculation algorithm of crank-angle resolved thermodynamic equations of the gas state in the engine cylinder enables the complete engine model to be integrated into the real-time environment of a physical model ship. Thus, the propulsion system's performance can be analysed under conditions that closely mimic those of the actual sea environment.

Investigation of the optimal timing and amount of fuel injection on the efficiency and emissions of a diesel engine through experimentation and numerical analysis

The purpose of this study is to investigate the performance, in-cylinder combustion, and emissions of the MTE660E heavy-duty diesel engine using 3D CFD simulation. The CFD simulation model based on AVL FIRE software was developed to numerically investigate the performance, in-cylinder combustion, and emissions of the MTE660E engine. The AVL model was validated against empirical data. The 6-cylinder MTE660E engine was operated under a constant excess air ratio of 1.75 and at 1600 rpm engine speed. The geometry and lattice design of the MTE660E engine were simulated to provide a computationally efficient approach. The AVL model was validated against experimental data and the error between the measured and calculated value of combustion characteristics and emissions was acceptable (R2> 90 %), error <5.6 %). Design Expert software was used to optimize the dependent variables (peak chamber temperature, brake mean effective pressure, engine torque, engine thermal efficiency and emissions of NOx) according to the studied variables (injection time and fuel injection quantity) based on response surface methodology. The results show that the recommended injecting time of 342 °C and the specific amount of fuel lead to better combustion efficiency, resulting in high engine performance and low emissions. The specific fuel consumption was highest at 2200 rpm with a 50 % load, while the lowest SFC level was observed at 1750 rpm with a 100 % load. The maximum value of NOx emissions was observed at full load. The findings show that the optimization of the injection timing and fuel injection quantity can effectively enhance the performance of the MTE660E engine. The study provides valuable insights into improving combustion efficiency, resulting in greater performance and reduced emissions without requiring expensive overhaul. It has potential applications in automotive and commercial transportation industries, thereby reducing fuel consumption and emissions.

Design and Failure Analysis of Piston Using Ansys

A piston is a component of reciprocating engines. The purpose of piston is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and a connecting rod. It is one of the most complex components of an automobile. In This project we are describes the Thermal analysis by using finite element method (FEM). The specifications used for designing the piston belong to four stroke single cylinder engine of piston. Modeling of piston is done using SOLID EDGE v20. static structural, Thermal and fatigue analysis is performed by using ANSYS WORKBENCH 2022 R1. The parameters used for the simulation are operating gas pressure, material properties of piston. The results predict the maximum stress and strain on pistons using FEA. The best material is selected based on static structural, thermal and fatigue analysis. The analysis results are used to optimize piston geometry of best two Materials

Investigating the Characteristics of Injecting and Spraying Methanol-Containing Fuel in a Diesel Engine

Introduction. The operation of eco friendly and high-efficiency internal combustion engines is not possible without deep and comprehensive study of using new types of fuels. That is why, forecasting the indicators of injecting and spraying in a diesel engine running on a mixed alcohol-containing fuel, which have a direct effect on the combustion and formation of toxic components and, as a result, on efficiency and eco friendliness, is an urgent scientific task.Aim of the Study. The study is aimed at developing a theoretical basis for calculating the characteristics of injecting and spraying methanol-containing fuel into diesel engine cylinders that allows optimizing its processes.Materials and Methods. There are considered the characteristics of injecting and spraying alcohol-containing fuel in a diesel engine modified to operate on a mixed methanol-containing fuel. There were used the well-known A.S. Lyshevsky dependencies, which fairly reliably reflect the processes of injecting and spraying in diesel engines.Results. The in-depth studies of the basic principles for evaluating the indicators of injecting and spraying standard fuel made it possible to adapt them for fuels of mixed methanol-containing composition and to investigate the dynamics of changes in the duration and speed of injection, the Weber criterion values, the boundaries between the areas of fuel jet forming, droplet size and spraying angle.Discussion and Conclusion. There has been developed a theoretical basis for calcu­lating the characteristics of injecting and spraying methanol-containing fuel that makes it possible to optimize the operation of a diesel engine running on mixed fuel and, as a result, improve its efficiency and eco friendliness. The presented numerically information on the change in the boundaries of the fuel jet forming areas, the size of the droplets and the angle of the spraying cone allows us to reliably determine the basic parameters of spraying of the used mixed methanol-containing fuels, determine the vector of optimization of the mixing processes and gives insight into the promising directions in designing the geometry of combustion chambers, intake ducts, etc.

Study on the influence mechanism of spoiler on flow and combustion process in rotary engine cylinder

Study on the influence mechanism of spoiler on flow and combustion process in rotary engine cylinder

Development of methods for adapting gas-diesel engines of agricultural tractors to LPG operation

This article describes the methods of organizing the non-detonation combustion of liquefied petroleum gases (propane-butane mixtures) (LPG) in the cylinder of a gas-diesel engine with a starting dose of no more than 25%, at maximum power modes. The addition of a part of the exhaust gases and water in a vaporous state to the fuel mixture, when using a nickel-based catalyst in the combustion chamber of a gas-diesel engine, which triggers the conversion reaction of lower alkanes, ensures reliable non-detonation combustion of the fuel charge. The nickel catalyst is an oxygen carrier, which ensures cyclical reactions near its surface in the combustion chamber of a gas-diesel engine: metal oxidation during purging of the combustion chamber; conversion of alkanes at compression and combustion cycles. The problem of carbonization of the catalyst is solved by burning deposits during the combustion of the fuel charge. The organization of a fuel vapor-gas-air mixture with subsequent combustion in the presence of a catalyst provides improved environmental, fuel and economic characteristics of a gas-diesel engine in the entire range of operating modes and increases its reliability.

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.

MODELING OF MIXTURE FORMATION IN A TWO-STROKE DIESEL ENGINE

The Ukrainian engine industry played a significant role in the creation, production, and improvement of the efficiency of two-stroke diesel engines with opposed mooved pistons and providing them with the highest indicators of liter and overall power. The results of research carried out at the department of engines and hybrid power plants of NTU "KhPI" reveal existing reserves for further improvement, ensuring world-class indicators and forming promising characteristics of two-stroke diesel engines of the 6DN12/2x12 series. Further developments to ensure a new level of power cannot be implemented exclusively by updating auxiliary units and systems. To create a promising power plant, the problem must be considered in a complex with an understanding of the physical and chemical processes in the engine cylinder. The two-stroke cycle and design features limit the possibilities of conducting experimental studies of engines of this type, and make it necessary to determine reserves for increasing their efficiency. In this case, the dissemination of ideas about the course of mixture formation processes in a two-stroke engine with lateral fuel injection becomes an urgent scientific and practical task. Solving this problem makes it possible to determine the reserves of increasing combustion efficiency in engines with reciprocating movement of pistons. Based on the results of the research, a mathematical model is proposed that allows us to determine the most rational ways of organizing mixture formation, provided the conditions of uniform distribution of fuel in the volume of the combustion chamber are ensured. The obtained results of the calculated studies are the basis for the development of structural elements, further experimental studies and the implementation of measures to ensure the further improvement of the mixing efficiency of two-stroke diesel engines of the 6DN12/2x12 series and their modifications.

CRITERIA FOR ASSESSING THE EFFECTIVENESS OF TRANSPORT POWER PLANTS DECARBONISATION IN ACCORDANCE WITH IMPLEMENTATION OF THE SUSTAINABLE DEVELOPMENT CONCEPT

The directions of restoration and further development of the energy sector in Ukraine are considered in accordance with power plants with internal combustion engines, taking into account the widespread implementation of the Sustainable Development concept, which allows solving existing modern social, economic and environmental problems. For Ukraine, taking into account the economic opportunities and selected priorities for the chosen path of development, it is necessary at this time to choose gradual and specific directions to implement the Sustainable Development concept. The most priority areas of practical implementation of the concept are determined and it is indicated that the effectiveness of this implementation is associated with the development of the industry on the basis of the fourth and fifth industrial revolutions (Industry 4.0 and Industry 5.0). One of the main tasks in solving the problems of the concept is to ensure the environmental component. Notwithstanding the noted progress in improving the environmental efficiency of internal combustion engines, further attention needs to be paid to the task of spreading the introduction of “green energy”, i.e. decarbonisation – reducing greenhouse gas emissions into the environment (CO2). The issue of decarbonisation in the future should be given the greatest attention both in the development and in the manufacture and operation of engines. It is shown that the assessment of the impact of CO2 emitted with the exhaust gases of internal combustion engines into the environment is carried out taking into account the model of operation of engines and the justification of the introduced adjustments. A new criterion is proposed, which is called: “ICE criterion of environmental thermal pollution”, which is proposed for use in studies to assess the effectiveness of the implementation of decarbonisation strategies in all modes of transport at implementation of the Sustainable Development concept in global transport power plants. A method for determining the efficiency of physical and chemical processes of mixture formation and combustion in internal combustion engine cylinders is proposed when using hybrid fuel with “green hydrogen” as its component, which allows determining the dependence of hydrogen influence on the level of engines effective performance and formation of harmful emissions in exhaust gases.

The Hydrogen Vehicle in the Context of the Sustainable Development of the Green Road Transport System

Abstract The scientific work presents concrete research carried out by the authors to implement some concepts of technical and managerial nature, so that those interested in this field can get acquainted with a certain way of exposing the problems concerning the hydrogen-powered vehicle, in the context of the sustainable development of the ecological road transport system. At the moment, the car whose energy for propulsion is generated by means of hydrogen or hydrogen fuel cells does not enjoy a high popularity among users, due to the very high purchase price (where we have high technology, we also have a price to match - a fuel cell is more expensive than an electric battery), the reluctance of the population to use this type of fuel, defined by the danger of explosions and fires generated by hydrogen, and the lack of hydrogen refueling stations in Romania and in some European countries. The use of alternative fuels in internal combustion piston engines has the advantage of significantly reducing pollution due to combustion products. With regard to the direct use of hydrogen as a fuel in internal combustion piston engines, we can say that it has proved its inefficiency, because the hydrogen injected or sucked directly into the engine cylinders is unstable, produces uncontrolled burns and detonations, and in the liquid state it is very difficult to store, it requires special transport methods, hydrogen tanks must be armored with Kevlar because hydrogen in the event of a car accident can explode. For example, if we use it as a fuel in a diesel engine, hydrogen may not ignite itself because the self-ignition temperature in the cylinders of compression-ignition engines is high (600°C). However, at a normal stoichiometric ratio, hydrogen has a high flame rate, much higher than gasoline. This creates a thermodynamic cycle of the thermal engine almost perfectly, but ideally, let us not forget that in poor mixtures of air-hydrogen the flame propagation speed is considerably reduced. The compression ratio of the engine is of utmost importance because it is finally defining the thermal efficiency of the engine. In the following, we present a technical and managerial study with engineering nuances, through which readers can look and understand the stage of development, place and role of the vehicle propelled by hydrogen fuel cells. Finally, the conclusions and further directions of research and development in the field addressed are presented.

Optimization of the intake system for the Setra NS 913 bus

Abstract The paper presents the implementation on buses of a dynamic air transfer system (SDTA) brand Air by Corneliu. That system is the subject of a patent entitled Dynamic Air Transfer Device RO 200900028. At the initiative of the Alba Iulia public Transport society, with a fleet of about 100 buses, we started a study on the efficiency of air intake in the internal combustion engine by implementing an SDTA. Since the air filter location on this bus model, Setra NS 913, is behind the rear axle wheels, the filter is exposed to dust, water and other particles thrown by the drive wheels, which leads to premature clogging and blockage of the filtration area, in the context in which the bus runs mainly on asphalt-free roads. The gas-dynamic resistance (filter permissiveness) would increase considerably, resulting in a severe reduction in the degree of filling of the engine cylinders. In order to eliminate the disadvantages mentioned above, respectively to increase the life of the air filter with implications on the performance of the engine, we have designed a dynamic system consisting of the following components: the air collector, located on the top of the bus; the grid housing, located on the suction grid; tubing, connecting element between the air collector and the grid housing. In order to realize the 3D model of SDTA, the specialized software VISI - CAD / CAM was used.

The Effect of Number of Spark Plug Ground Electrodes and Octane Rating on Single Cylinder Engine Performance

The Effect of Number of Spark Plug Ground Electrodes and Octane Rating on Single Cylinder Engine Performance

Numerical and experimental analyses for performance and emissions assessment of a four-stroke engine powered by oleic acid methyl ester biofuel made from waste frying oil

&lt;p style="text-align:justify"&gt;&lt;span style="font-size:11pt"&gt;&lt;span style="line-height:150%"&gt;&lt;span style="font-family:Calibri,sans-serif"&gt;&lt;span lang="EN-US" style="font-size:12.0pt"&gt;&lt;span style="line-height:150%"&gt;&lt;span style="font-family:&amp;quot;Times New Roman&amp;quot;,serif"&gt;Recently, several earlier works conducted research works dedicated to replacing fossil-based fuels with environmentally friendly ones. The goal of the research is to construct a multivariate linear regression model for the attributes of a four-cylinder diesel engine fueled by biodiesel. In this context, the goal of the research is to structure a multiple linear regression example for characterizing a four-cylinder engine fueled by biodiesel. In fact, experimental research was conducted on an agricultural tractor equipped with a 4-cylinder direct-injection diesel engine. The biodiesel is made from waste frying oil without blending referred to as the oleic acid methyl ester (OAME) biofuel. The biodiesel was extracted through a chemical transesterification reaction. The four-stroke engine is tested for both pure OAME biofuel and conventional diesel. One-dimensional numerical simulations were conducted. A strong correlation between numerical and experimental data was observed, validating the numerical model. Using the engine model, in-cylinder pressure, heat release rate, in-cylinder temperature, and emissions including Carbon monoxide (CO), nitrogen oxides (NO&lt;sub&gt;x&lt;/sub&gt;), and Carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) were recorded across a broad range of engine operating speeds. Additionally, brake-specific fuel consumption (BSFC) and brake power were numerically calculated and compared to experimental data. The results showed that usage of the OAME as a biofuel could be a promising solution that enables similar performances with lower CO emissions compared to petroleum diesel particularly at low engine speeds.&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;

The comparative performance study of the EF7 downsized engines; fuel economy besides CO2 reduction

Engine downsizing is considered a strategic idea in fuel economy enhancement as well as reduction. It is defined in the literature as the decrease in engine geometrical dimensions besides its performance being fixed. In this research, the Iranian gasoline-fueled national engine, EF7, has been investigated for 25% downsizing. After introducing the gasoline-fueled and CNG-fueled versions of downsized engines, their performance, besides release rates are studied in detail. A one-dimensional engine simulator coupled with a 3D-CFD model is developed to carry out such an investigation, an experimental test setup is provided to evaluate the accuracy of the provided numerical model, as well. The first version of presented downsized engines, called EF7, is a 3-cylinder engine with the same geometrical characteristics as the base engine, which is equipped with a turbo-charger and dual CVVT technologies. The EF7 is then introduced by fuel shifting to CNG as the second version of downsized engines, and finally, increasing the compression ratio, the EF7 is presented as the third version of studied-downsized engines. The results show almost the same rate of BSFC besides a 3.4% reduction in concentration for EF7, 20.6% fuel economy enhancement, besides 20.8% reduction in the specific release rate for EF7, and 28.8% fuel economy enhancement, besides 25.3% reduction in the specific release rate for EF7 in comparison with the base engine.