AVL FIRE Research Articles

Effects of the Injector Spray Angle on Combustion and Emissions of a 4-Stroke Natural Gas-Diesel DF Marine Engine

This work studied the effect of the injector spray angle (SA) on the combustion and emissions of a 4-stroke port-injection natural gas-diesel dual-fuel (NG-Diesel DF) marine engine to determine the optimal SA for the fuel injector, aiming to reduce exhaust gas emissions while keeping the engine performance. Three-dimensional (3D) simulations of the combustion process and emission formations occurring in the engine cylinder in both diesel and DF modes were carried out using the AVL FIRE R2018a code. The engine’s in-cylinder temperature, pressure, and emission characteristics were analyzed. To clarify the effect of the injector SA on the combustion and emission characteristics of the engine, only the injector SA has been varied from 145 to 160°. Meanwhile, all other boundary conditions for the simulations and operating conditions of the engine have remained unchanged. The simulation results have been compared and showed a good agreement with the engine experimental results. The study has successfully investigated the effects of the injector SA on the combustion and emission characteristics of the engine. A better SA for the fuel injector, to reduce the NO emissions (145°) or soot and CO2 emissions (150°), while keeping the engine power almost unchanged, without the use of any exhaust gas post-treatment equipment, has also been suggested.

A Simulation Study of the Effect of HCNG Fuel and Injector Hole Number along with a Variation of Fuel Injection Pressure in a Gasoline Engine Converted from Port Injection to Direct Injection

The number of injector holes and the fuel-injection pressure in an internal combustion engine can affect engine performance and exhaust emissions. Conversion of a port-injection gasoline engine to an HCNG direct-injection engine improves engine performance and exhaust emissions. In addition, increasing the injection pressure helps to increase engine performance. In this study, AVL Fire software was used to perform simulation by certain adjustments. The injection pressure was applied in mods of 15, 20, and 25 bars, the injector holes numbers were 3 and 6, the compression ratio changed from 10:1 to 14:1, and the amount of hydrogen enrichment to natural gas was in mods of 10%, 20%, 30%, and 40%. This paper discusses the items above with regard to power, torque, combustion chamber pressure, fuel conversion efficiency, and exhaust emissions. The result determined that increasing the number of injector holes improves the performance engine and reduces CO emission so that the contour plots confirmed the balanced distribution of temperature and pressure. According to obtained results, maximum engine performance improved from 2.5% to 5% at different speeds and 30% added hydrogen, 25 bar injection pressure, and 6-hole injectors. The amount of CO decreased by approximately 30%, and NOx increased by about 10%.

Профилирование торцевых окон трохоидной машины

There is a proposal of a method for the profiling the end windows of trochoid rotary machines according to the given geometric parameters for constructing the trochoid and the degree of gas pressure increase. Its area of application is rotary piston engines and trochoid compressors and pumps. Verification of the mathematical model was carried out on the basis of gas flow simulation data in a three-dimensional setting in the AVL Fire software package. The model of the working process of a trochoid machine is based on the fundamental equations of momentum, energy, diffusion and continuity, written in the Reynolds form and supplemented by the k–?–f turbulence model. The developed method makes it possible to estimate quickly the throughput of the windows of a trochoid rotary machine with less computing resources than in a three-dimensional calculation.

Soot Distribution Characteristics and Its Influence Factors in Burner-Type Regeneration Diesel Particulate Filter

The burner-type regeneration diesel particulate filter is one of the most widely used diesel particulate filters. Using AVL FIRE, a 3D model of a burner-type regeneration diesel particulate filter (DPF) was established, and simulation analyses were carried out. The effects of the exhaust parameters (temperature, exhaust mass flow rate, and soot load) and the structural parameters (channel density, inlet/outlet channel ratio, and the length–diameter ratio) on soot distribution (soot mass concentration and soot thickness) were analyzed. The results show that the soot distribution characteristics of regenerative DPF with a burner are as follows: the soot mass concentration first rapidly rises to the maximum value and then rapidly decreases to a low value, and the dust thickness gradually increases with the increase in location. With the increase in exhaust mass flow rate and soot load, soot mass concentration and soot thickness increase. With the increase in temperature, the mass concentration and thickness of the ash decreased. When the temperature exceeds 750 K, soot begins to regenerate. Among the exhaust parameters, the mass flow rate of the exhaust has the greatest influence on the soot distribution. The length–diameter ratio, the ratio of the inlet and the outlet channel, and channel density have little effect on the mass concentration of soot, and the soot mass concentration increases with the increase in channel density. In addition to the length–diameter ratio of 2.1, the soot thickness increases with the increase in the length–diameter ratio, and the rising rate is also accelerated. The thickness of soot decreased with the increase in channel density and the ratio of the inlet and the outlet channels. When the channel density is more than 250, the change in soot thickness is basically the same. When the ratio of the inlet and the outlet channels exceeds 1.3, the change in the soot thickness is basically the same. Among the structural parameters, channel density has the greatest influence on the soot distribution.

An empirical and CFD analysis of combustion performance of a diesel engine fueled with tomato seed oil biodiesel

Abstract Tomato seed oil biodiesel (TSOB) could be considered as a second generation and clean-burning renewable substitute for petroleum diesel. It is about 72% by weight of tomato waste, which contains an average of 24% oil. This paper investigated the effects of four different Diesel-TSOB blends on the combustion performance of an indirect injection (IDI) diesel engine. In-cylinder pressure (CP) and combustion parameters at five different engine loads and seven speeds were experimentally measured. Then for 2D CFD simulation of the emissions and combustion processes, AVL FIRE software was used and the results evaluated with experimental data. The purpose of the study was to determine the combustion process and its effects on the performance and emissions of the engine. The outcomes for B10 at 100% load addressed that, the peak CP of about 67 MPa was found at 1200 rpm which occurred at 13° ATDC, while at 2200 rpm the peak CP was 69 MPa and occurred at 1° ATDC, and at 2400 rpm the peak CP was found to be about 66 MPa which occurred approximately at TDC. The simulated results found that the peak in-cylinder temperature of 1600° K corresponds to the 10% TSOB blend (B10) and the longest mixing-controlled period occurs for B10 at 27° CA. The simulation also showed that B5 had the longest jet penetration of about 44 mm (at about 100° CA) in comparison to 43 mm for B20, 41 mm for B10 and 39.8 mm for B0 (pure diesel) which occurred at less than 100° CA. The longest jet penetration duration of was found to be about 44 mm for B5 at about100° CA. The results showed that B10 has the biggest accumulative heat release (approximately 1900 J) and highest fuel energy efficiency. The 2-D CFD simulation revealed that the unburnt equivalence ratio in the main combustion chamber is lesser than in the spherical combustion chamber.

Effects of Injection Timing and Injection Volume on the Combustion and Emissions of a Two-Stroke Kerosene Direct Injection Engine

To study the influence of injection time and injection volume on the working process of a two-stroke kerosene direct injection engine, an experimental study was carried out on an improved two-stroke inline three-cylinder gasoline engine, combined with calculations and analysis with GT-POWER and AVL FIRE software. The results showed that when the injection end angle increased from 50° to 70° before the top dead center (BTDC), the average pressure and temperature in the cylinder increased rapidly, the peak value of pressure and temperature and the cumulative heat release increased, and the combustion process in the cylinder was more sufficient. The fuel injection volume was set to 7.5 mg, 8 mg, and 8.5 mg. With increasing fuel injection volume, the average pressure and average temperature first increased and then decreased, the peak value gradually increased, the heat release rate and cumulative heat release increased sharply, the corresponding time gradually advanced, and the peak value gradually increased. With increasing fuel injection volume, CO, NO, and soot gradually increased, while CO2 slightly decreased.

CRI diesel injector transient heat–mass transfer with combustion-pollution indicated parameters consideration for Helical Orifice by various needle profiles

In the present paper, the effect of using Helical Orifice on transient heat-mass transfer and Combustion Indicated Quantities has been investigated in High Pressure Liquid Fuel Injector for different needle Movements using Avl Fire CFD code. The effect of each of the proposed needle movement profiles (triangular, trapezius, and boot) with the help of a three-dimensional moving mesh by numerical model in AVL Fire software, which has been validated with experimental data in each part, on the performance of the diesel engine and its air emission species has been investigated. Numerical results show that spiral nozzle leads to a rotational flow of fuel spray, increasing the spray cone angle and turbulence intensity inside the combustion chamber. Spiral Nozzle has more mean pressure and temperature than simple geometry of nozzle. Spiral motion leading to increasing turbulent kinetic energy and having more mean pressure, temperature, and wall heat flux. Increasing the resulting spray cone angle improves the performance of the diesel engine by reducing fuel consumption and increasing power and torque, and the production of nitrogen oxide and carbon monoxide pollutants due to a better fuel-air mixture, increased turbulence intensity and average temperature inside the chamber. fuel consumption decreases by 30% and its power and torque increase 55%. Also in this case, carbon monoxide pollutants decrease by 38% and nitrogen oxide pollutants decreasing by 30% for spiral nozzle with trapezius profile for needle movement.

The effect of HDPE and LDPE pyrolytic oils on cavitation formation in a common-rail diesel injector

Plastic production and usage increase every year due to its practicality, adaptability, and low-cost production. The problem with plastic arises when it becomes waste and needs to be treated. Most of the plastic we use is produced from petrochemical material that can be used in resource recovery processes like pyrolysis to produce various materials. One of the pyrolysis process products is pyrolytic oil, whose properties are similar to conventional fuels. Minor differences in fuel properties can influence the injection process, in-nozzle flow condition, spray formation and break-up, the combustion process, etc. The presented paper aims to study the influence of pyrolytic oil‘s properties on cavitation formation in the injection nozzle of a common-rail injector. First, the pyrolytic oils were obtained from waste high- and low-density polyethylene using a pyrolysis reactor. Afterwards, the oils were characterized and implemented in the AVL FIRE computation program for studying their influence on cavitation formation in the injection nozzle hole. The obtained results indicate slight differences in fuel properties that influence cavitation formation and spread in the injection hole, which further influence conditions at the exit of the injection hole. The lower lower viscosity of pyrolytic oils influences lower friction in the fuel nozzle flow. The lower densyt and viscosity of pyrolytic oils promotes cavitation formation, advance time of it appearance at injection hole exit and influence the shorter presence of cavitation in the needle closing phase.

A numerical approach in the investigation of the effects of diethyl ether and ethanol mixtures on combustion characteristics and NO emissions in a DI diesel engine

In this study, the effects of adding ethanol and diethyl ether to diesel fuel on combustion characteristics and NO emissions were numerically investigated. 100% diesel fuel (D100) and by volume 90% diesel+10% ethanol blend (D90E10), 80% diesel+20% ethanol blend (D80E20), 80% diesel+10% ethanol+10% diethyl ether blend (D80E10DEE10) and 85% diesel+ 10% ethanol+5% diethyl ether mixture (D85E10DEE5) was used as fuel. Analyzes were carried out using a single cylinder direct injection diesel engine at 2000 and 3000 rpm engine speed conditions. AVL FIRE software was used for numerical study. In-cylinder pressure, cumulative heat release rate, turbulent kinetic energy (TKE), NO emissions and velocity distributions in the combustion chamber were investigated for five different fuel types. As a result, the in-cylinder pressure and heat release rate of ethanol and diethyl ether blended fuels were lower than diesel fuel at both speeds. This is due to the calorific value of the fuel. It was observed that NO emissions decreased as the ethanol content in the fuel increased. For both engine speeds, the highest TKE value was obtained in D90E10 mixed fuel, and the lowest value was found in D80E10DEE10 mixture fuel. Ethanol positively affected the turbulent kinetic energy. The flow rate of ethanol was higher than diesel and diethyl ether fuel.

The effect of EGR and hydrogen addition to natural gas on performance and exhaust emissions in a diesel engine by AVL fire multi-domain simulation, GPR model, and multi-objective genetic algorithm

In this study, the effect of adding hydrogen to natural gas and EGR ratio was conducted on a diesel engine to investigate the engine performance and exhaust gases by AVL Fire multi-domain simulation software.For this investigation, a mixture of hydrogen fuel and natural gas replaced diesel fuel. The percentage of hydrogen in blend fuel changed from 0% to 40%. The compression ratio converted from 17:1 to 15:1. The EGR ratios were in three steps of 5%, 10%, and 15%, with different engine speeds from 1000 to 1800 RPM. The Gaussian process regression (GPR) was developed to model engine performance and exhaust emissions. The optimal values of EGR and the percentage of hydrogen in the blend of HCNG were extracted using a multi-objective genetic algorithm (MOGA).The results showed that by increasing EGR, thermal efficiency, the engine power, and specific fuel consumption decreased due to prolongation of combustion length while cumulative heat release increased but, its effect on cylinder pressure is insignificant. Adding hydrogen to natural gas increased the combustion temperature and, consequently NOx. While the amount of CO and HC decreased. The results of GPR and MOGA illustrated that at different engine speeds, the optimum values of EGR and HCNG were 6.35% and 31%, respectively.

Experiment methods and apparatus for finely controlled partial needle lift measurements with a gasoline direct injector

In this study, an experiment method and apparatus are developed which allow exploration of partial-lift spray in a production gasoline direct injection (GDI) injector. For this injector, discretizing the needle’s stroke into a series of steady partial-lift tests seems a viable approach for quantifying transient behavior, where spray performance is often inferior from the perspective of emissions. However, performing such tests is not trivial due to manufacturing challenges and material limitations making it difficult to isolate any particular lift at pressure. To explore the applicability of fixed partial-lift tests, the following are performed: (1) An inward-opening multi-hole GDI injector is minimally modified with an apparatus to finely control needle lift by limiting the needle’s stroke with a fine micrometer head. (2) An experiment process is developed to associate the micrometer set-point with the imposed needle lift, compensating for pressure induced component flex. This flex is significant and of a similar magnitude to the needle’s stroke. (3) In-nozzle flow is simulated using computational fluid dynamics (CFD) within the AVL FIRE software to compare a stationary and moving needle. The comparison reveals a relative insignificance of needle velocity for the majority of the needle’s stroke (>5 μm). The nozzle hole flow rates and effective exit velocities are similar, suggesting fixed partial-lift spray well approximates the normally moving needle spray. This new experiment method can be used on current injectors to quantify spray performance during needle transients by discretizing the stroke into steps as small as 2 μm, exceeding the control in any current published literature.

Investigation of Diesel Engine Combustion Characteristics for Varying Nozzle Depth at Different Spray Angles

The demand for petroleum-derived fuels is increasing every day despite their speculations about the exhaustion of petroleum fuel. Petroleum-derived fuels are classified as a suspect element for humans due to their known primary adverse effects on the environment. The concern is that the demand for petroleum fuel will rise along with the market price. Researchers around the world focus on reducing the harmful effects of petroleum fuel or finding some other substitute for petroleum fuels. A Kirloskar single cylinder diesel engine (model TV-1) was selected for simulation using commercially available AVL FIRE software. The published articles indicate the operating conditions and limitations of the single cylinder diesel engine. The geometry of the hemispherical cup piston is generated and networked in software, then the search is processed by selecting three different spray angles, such as 120o, 140o, and 160o. The standard spray angle is 120o. In addition, four nozzle depths are included in the search to analyze the effect of nozzle depth on combustion parameters. The nozzles are available in four depths: 0.5 mm, 1 mm, 1.5 mm, and 2 mm. while the nozzle depth is 1 mm standard nozzle depth. Four nozzle depths with spray angles of 120°, 140°, and 160° are examined. The results returned the combustion parameter and depend on the spray angle and the depth of the nozzle. To obtain an adequate combustion result from the above scenario, some trade-offs in terms of combustion parameters need to be considered.

The effect of fuel injection pressure and combustion chamber configuration on fuel spray, combustion and emissions of a direct injection diesel engine: a CFD approach

In the present study, the combined impacts of injection pressure and piston bowl configuration on fuel–air mixing, combustion and emissions of a diesel engine have been analysed numerically. An investigation has been conducted at four different fuel injection pressures and three different combustion chamber configurations for the same bowl volume to have a constant compression ratio. The in-cylinder transient flow and subsequent turbulent combustion process have been modelled using computational fluid dynamics code AVL FIRE. The predicted results indicate that the brake-specific fuel consumption (BSFC) is decreased by 4.19%, 8.96% and 11.92% for HCC, 5.77%, 9.92% and 13.68% for CCC, and 5.13%, 9.19% and 12.92% for TRCC when engine operates with an injection pressure of 215, 230 and 250 bar, respectively compared to 200 bar at full load operation. Soot emissions for CCC and TRCC engines are decreased by 23.4% and 33.43%, respectively, compared to baseline HCC engines.

Расчетно-экспериментальное исследование рабочего процесса перспективного роторно-поршневого двигателя

The article considers mathematical model in a three-dimensional setting developed to study the Wankel engine working process. The verification of the mathematical model is carried out on the basis of measured unsteady pressures in the combustion chamber and in the inlet and outlet ports of a Wankel engine. The engine workflow model is based on the fundamental equations of momentum, energy, diffusion and continuity, written in Reynolds form and supplemented by a k-?-f turbulence model. Fuel combustion was simulated using the Extended Coherent Flame Model (ECFM). Numerical experiments were carried out using the AVL FIRE software package. The paper considers in detail the effect of the movement of the air-fuel mixture in the combustion chamber of a Wankel engine, considering the intake and exhaust processes in adjacent chambers and the gas overflows from the volumes of spark plug channels into the main chamber on the combustion processes and the engine performance. The effect of the movement of the air-fuel mixture in the combustion chamber of a Wankel engine on the combustion processes and engine performance is considered in detail taking into account the processes of intake and exhaust in adjacent chambers and the leakage of the working fluid from the volumes of the spark plug channels into the main chamber.

A numerical study on the effects of charge air temperature on the combustion and emission characteristics of a marine generator engine

A numerical study was carried out to investigate the effectiveness of the charge air cooling method on the exhaust gas emission reduction when applied to a four-stroke marine generator diesel engine at full load. The AVL FIRE 2018a software was used to perform three-dimension (3D) simulations of the combustion process and emission formations inside the engine cylinder operating with various charge air temperatures (CATs). The simulation results were then verified by measured values obtained from experiments in the Green Ship Technology laboratory (GSTLab), Korea. The simulation results showed In-Cylinder peak pressure increase tendencies as the CAT decreased from 360 K to 320 K, leading to an increase in the brake mean effective pressure (BMEP) by 10.74%. At the same time, the In-Cylinder peak temperature was decreased, resulting in a reduction in NO emission by 33.85%. Soot, CO, and CO2 emissions were also reduced by 63.92, 44.66, and 3.22%, respectively. In addition, the CAT cooling method also reduced specific fuel oil consumption (SFOC) by 9.68% due to the increase in the indicated efficiency. This study would be a useful material for operating engines in cases of trying to reduce exhaust gas emissions from existing engines without any additional emission post-treatment device.

Effects of Plateau Environment on Combustion and Emission Characteristics of a Plateau High-Pressure Common-Rail Diesel Engine with Different Blending Ratios of Biodiesel

Taking a plateau high-pressure common-rail diesel engine as the research model, a model was established and simulated by AVL FIRE according to the structural parameters of a diesel engine. The combustion and emission characteristics of D, B20, and B50 diesel engines were simulated in the plateau atmospheric environment at 0 m, 1000 m, and 2000 m. The calculation results show that as the altitude increased, the peak in-cylinder pressure and the cumulative heat release of diesel decreased with different blending ratios. When the altitude increased by 1000 m, the cumulative heat release was reduced by about 5%. Furthermore, the emission trend of NO, soot, and CO was to first increase and then decrease. As the altitude increased, the mass fraction of NO emission decreased. As the altitude increased, the mass fractions of soot and CO increased. Additionally, when the altitude was 0 m and 1000 m, the maximum temperature, the mass fraction of OH, and the fuel–air ratio of B20 were higher and more uniform. When the altitude was 2000 m, the maximum temperature, the mass fraction of OH, and the fuel–air ratio of B50 were higher and more uniform. Lastly, as the altitude increased, the maximum combustion temperature of D and B20 decreased, and combustion became more uneven. As the altitude increased, the maximum combustion temperature of B50 increased, and the combustion became more uniform. As the altitude increased, the fuel–air ratio and the mass fractions of OH and NO decreased. When the altitude increased, the soot concentration increased, and the distribution area was larger.

Non-Vaporizing and Vaporizing Diesel Spray Evaluation with Experimental and Computational Approaches

Experimental and numerical modeling of diesel spray is necessary to understand the idea of efficient combustion and injection strategies in diesel engines. The current study aims to demonstrate the experimental and computational modeling of diesel spray under non-evaporating and evaporating conditions using three single hole injector diameters i.e. 0.133mm, 0.122mm and 0.101mm with injection pressure and injection quantity of 120 MPa and 5 mm3, respectively. First, the non-evaporating experiments are performed in high-pressure high-temperature constant volume vessel where the spray images are captured with High-Speed Video (HSV) camera using Diffused Background Illumination (DBI) method. However, evaporating spray experiments implement LAS technique to measure mixture concentration as well as visualize liquid and vapor phases of evaporating spray. The experimental results are then validated with computational simulation using AVL FIRE commercial CFD code. The CFD code uses Reynold’s Averaged Navier Stokes (RANS), KHRT and Dukowicz model as turbulence, spray breakup and evaporation models, respectively. Good agreement can be found between experimental results and CFD simulation in terms of spray tip penetration, spray angle and spray cone angle for non-evaporating case and equivalence ratio distribution, liquid/vapor penetration lengths and evaporation ratio for evaporating sprays. Thus, this work can be considered as successful validation for CI engine under similar spray conditions.

Numerical simulation of a heavy-duty diesel engine to evaluate the effect of fuel injection duration on engine performance and emission

Due to the limited space in transport vehicles, the CI engines with high power density has always been a priority. In heavy-duty diesel engines, direct injection results creation of the lean region in the space of the combustion chamber. Increasing the fuel penetration by changing injection duration is an effective solution to achieve homogenous mixture. In this paper, impact of changing Injection duration in upgraded MTU-4000-R43L diesel engine on power characteristics, rate of heat release (RoHR), combustion phasing, emission and, most importantly, the gradient of pressure changes as a characteristic of the vibration and knocking of the engine, has been studied numerically. Numerical simulation is performed in AVL Fire which is coupled with reduced detail chemical kinetics. the fuel Injection duration was varying from 14.6 to 35.6 oCA, the in-cylinder mean pressure, the IMEP decreases and the ISFC increases; however as the fuel Injection duration decreases, the pressure gradient rises; from the range of 30.6 degrees onwards, the reduction of the fuel Injection duration leads to a severe knock of the engine and as a result reduces its engine life. Emission results also showed that CO2 and NOx increased and CO reduced with decreasing fuel decreasing Injection duration.

COVID-19 aerodynamic evaluation of social distancing in indoor environments, a numerical study.

PurposeMany countries worldwide have taken early measures to combat the spread of coronavirus SARS-CoV-2 by implementing social distancing measures. The main aim of the present work is to examine the feasibility of social distancing (i.e. 1.5 m) in closed spaces taking into account the possibility for airborne transmission of SARS-CoV-2.MethodsA 3D numerical model of human respiration activities, such as breathing and speaking within indoor environments has been simulated with CFD software AVL FIRE R2020. The Eulerian-Eulerian flow model coupled with k-Ɛ approach were employed. With regard to breathing mode, the infected individual is modelled to be breathing 10 times per minute with a pulmonary rate of 6 L/min with a sinusoidal cycle. The present investigation considered air and droplets/particles as separate phases.ResultsThe predicted results suggested that the social distancing (i.e. 1.5 m) is not adequate to reduce the risk of contracting diseases like COVID-19, especially when staying for a longer period in an indoor environment. The person directly facing the infected person inhaled more than 1000 aerosol droplets within 30 min. The results also showed approximately 65 % decrease in the number of inhaled droplets the room is well ventilated.ConclusionsWithin an indoor environment, 1.5 m distance will not be enough to protect the healthy individuals from the droplets coming from an infected person. Also, the situation may become worse with the change of the air ventilation system.

Effects of Various Fuels on Combustion and Emission Characteristics of a Four-Stroke Dual-Fuel Marine Engine

A numerical study was carried out to investigate the effects of methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), and dimethyl ether (DME) on the combustion and emission characteristics of a four-stroke gas-diesel dual-fuel (DF) marine engine at full load. Three-dimensional simulations of the combustion process and emission formation inside the engine cylinder in the diesel and DF modes were performed using the AVL FIRE R2018a simulation software to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results agreed well with the measured values reported in the engine shop test technical data. The simulation results showed reductions in the in-cylinder peak pressure and temperatures, as well as the emission formations, in the DF modes in comparison to the diesel mode. The DF mode could significantly reduce nitric oxide (NO) emissions (up to 96.225%) of DME compared to the diesel mode. Meanwhile, C3H8 and CH4 fuels effectively reduced the soot (up to 82.78%) and carbon dioxide (CO2) emissions (by 21.33%), respectively, compared to the diesel mode. However, the results also showed longer ignition delay times of the combustion processes when the engine operated in the DF mode, particularly in the DME-diesel mode. The combustion and emission characteristics of the engine were also analyzed when varying the injection timing; the results showed that applying the injection timing adjustment method could further address NO emission problems but led to a decrease in the engine power. Therefore, it is necessary to consider the benefits and disadvantages of adopting the injection timing adjustment strategy to address certain engine emission problems. This study successfully analyzed the benefits of using various gas fuels as alternative fuels and the injection timing adjustment method in DF marine engines to meet the International Maritime Organization (IMO) emission regulations without the use of any emission after-treatment devices.