Full Length ArticleInvestigation on the combustion and emission characteristics of diesel engine fueled with diesel/methanol/n-butanol blends
Introduction
The diesel engine has the advantages of high thermal efficiency [1], low fuel consumption [2], high output power, and good safety [3], and is widely used in automobiles, agriculture, and industry [4]. Similarly, CO, PM, and NOx emissions from diesel engines threaten public health and the ecosystem [5]. In order to meet this challenge and the requirements of resource shortage and environmental problems, many automobile manufacturers and researchers have no choice but to improve engine technology and find alternatives to fossil energy [6]. To support this, the governments and institutions should encourage and implement national energy policies and reduce dependence on traditional fuels [7]. A practical solution is to add oxygenated fuel or additives to diesel. In diesel engines, oxygenated fuel can reduce engine emissions of soot, nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide (CO2), and unburned hydrocarbons (HC), and improve combustion characteristics [8]. Alcohol is an oxygenated fuel. Its combustion performance is different from diesel. It has fast flame propagation speed, high efficiency, good quality, low CO and HC emissions, and low engine temperature [9]. Therefore, the alcohol fuel has attracted more and more researchers' attention in recent years. Among all oxygenated biofuels, alcohol has been widely studied in the past few decades. Alcohol molecules contain hydroxyl (OH), so it can reduce engine soot emission during diesel blended combustion, which is helpful to achieve cleaner combustion.
At present, the research on alcohol fuels mainly focuses on methanol [10], ethanol [11], propanol [12], butanol [13] and pentanol [14]. Among all alternative fuels, the short-chain alcohol-based biofuels such as methanol and ethanol have attracted much attention because of their mature production process and high oxygen content [15]. In addition, the combustion and emission characteristics of engine can be improved due to the advantages of high octane number, high latent heat of vaporization, and good lean combustion [16]. For example, methanol is a relatively clean liquid fuel that can be converted from coal and natural gas. It can effectively use coal, coal bed methane, and coke oven gas. The utilization rate of inferior coal can be improved while reducing crude oil consumption. Methanol is a liquid fuel, and its storage and transportation are similar to diesel [17]. The cost of methanol is about one-third of that of gasoline and diesel, which makes the market prospect of methanol quite broad. Yao et al. [18] studied diesel-methanol compound combustion (DMCC) and found DMCC reduced soot and NOx emissions. Berber [19] studied the effect of adding methanol to diesel on the engine. The results showed that the addition of methanol reduced the emissions of CO2 and CO. In addition, Dou et al. [20] showed that the number of particles gradually decreased with the increasing methanol ratio. However, methanol and diesel differ significantly in polarity and are challenging to be miscible [21], and the fuel stability after blending methanol and diesel is poor [22]. Compared with pure diesel, methanol/diesel blended fuels reduce engine brake thermal efficiency (BTE) and increases HC and CO emissions [23]. Therefore, these problems greatly limit the application of methanol as an alternative fuel for diesel engines.
In recent years, the long-chain alcohols containing four or more carbons have had significant advantages over short-chain alcohols in diesel engines. Long-chain alcohols have higher energy density and higher cetane numbers than short-chain alcohols. They also have good blending stability and can be blended with diesel at a large blending ratio. In addition, long-chain alcohols have low moisture absorption and are easy to store and transport [24]. N-butanol is a four-carbon alcohol that has been widely studied as an alternative fuel or fuel additive in recent years [25], [26]. N-butanol can be produced from food waste, biome, eukaryotes, and other plant components containing cellulose [27]. It is a potential alternative, which can be used alone or blended with traditional fuels to reduce dependence on fossil fuels and reduce particulate emission (PM) without significant impact on NOx or cetane number [28]. Compared with methanol and ethanol, n-butanol has a higher calorific value and viscosity, lower volatility and latent heat of vaporization, and lower hygroscopicity [29] and corrosivity [30]. In addition, n-butanol has better miscibility with diesel than methanol or ethanol [31]. Because n-butanol has its advantages, more and more studies on n-butanol as a fuel additive have been carried out in recent years. These studies generally showed that using n-butanol petroleum-based diesel blends could achieve cleaner emission without significantly reducing engine performance [32]. Satsangi et al. [33] studied the effects of n-butanol/diesel blends on an internal combustion engine's combustion noise, performance, and emission characteristics. The results showed that n-butanol/diesel blended fuel had higher pressure and heat release rate (HRR) than pure diesel fuel. Studies have shown that [34] n-butanol is a high-quality renewable alternative fuel and can be used as a cosolvent of diesel and methanol blended fuel. Zhang et al. [35] studied n-butanol added to diesel/biodiesel blends on engine performance and particulate emission. The results showed that the addition of n-butanol could reduce PM emission and improve engine performance characteristic. Sharon et al. [36] studied the effects of palm oil, n-butanol, and diesel mixture on the performance and emission characteristics of diesel engine. The results showed that adding n-butanol could reduce CO and NOx emissions, reduce flue gas opacity and improve BTE. Tüccar et al. [37] had carried out similar research and obtained a similar conclusion. In addition, Chen et al. [38] studied the combustion and emission characteristics of diesel, n-pentanol, and methanol blends on a common rail diesel engine. The results showed that the opacity and soot emission of diesel/n-pentanol/methanol blends were lower than pure diesel. However, there are few studies on diesel/methanol/n-butanol blends.
With the developments of the economic and technology, the computational fluid dynamics (CFD) simulation technology has been widely used. Compared with the traditional production technology, the CFD simulation technology has the advantages of low cost and short cycle. It can use the data information generated in the product's whole life cycle to simulate the working state of the product in the virtual environment and finally achieve the optimization of the product by modifying the parameters. For example, CFD based on the electronic computer can simulate automobile design, manufacturing, and optimization with a small error using a discrete mathematical algorithm, significantly shortening the research and development cycle. At present, the popular CFD software includes ANSYS Fluent, AVL-Fire, CONVERGE, etc. For example, Fan et al. [39] studied the mixture formation and combustion of direct hydrogen injection and natural gas rotary injection engines through ANSYS Fluent software. The results showed that hydrogen stratification became more and more evident with the delay of injection time. Luo et al. [40] established the CFD model to study the influence of injection strategy on diesel engine combustion and emission characteristics in AVL-Fire environment. Kattela et al. [41] had developed a CFD model to investigate the engine performance and emission characteristics of diesel engine fueled with butanol/diesel blends as fuel. The results showed that the blending of butanol could reduce engine emission. Chen et al had developed a CFD model and investigated the air–fuel interactions in SIDI optical engine. They found that fuel injection led to air entrainment, which affected the air flow between fuel plumes and the fuel spray speed was slightly correlated with this air flow enhancement [42]. In addition, a 3-CFD model had been developed and verified by experimental result by Chen et al [43]and they found that the expectations were in full agreement with the 3D images [44]. Thus, the simulation can be widely used in the design of diesel engine.
Above all, the behaviors of diesel/methanol/n-butanol blended fuel are different due to the different thermos-physical properties. In this paper, a CFD simulation model of diesel engine was established by CONVERGE 3.0 coupled with CHEMKIN Ⅱ and verified by the experimental results. In addition, the effects of different blending ratios on the spray, combustion and emission characteristics of diesel engine fuel with diesel/methanol/n-butanol blend fuels were investigated. This study has specific practical and academic significance for reducing diesel vehicle pollution emission and realizing source emission reduction.
Section snippets
Model set-up and calibration
In this paper, the combustion chamber geometry was established by using AutoCAD software. CONVERGE Studio was used to arrange the boundaries, set up the calculation model and change the calculation conditions. CONVERGE software can automatically generate high-quality hexahedral-based orthogonal meshes based on the input geometry directly in real time. Firstly, the geometric model of the combustion chamber was established by AutoCAD software and saved in STL format. Then the STL file was
Fuel physical parameters
In this study, D100 represents pure diesel without any alcohol fuel; D80M20 represents 80% diesel and 20% methanol by vol.; D70M20B10 represents 70% diesel, 20% methanol and 10% n-butanol by vol.; D70M15B15 represents 70% diesel, 15% methanol and 15% n-butanol by vol.. Detailed physical properties of the fuel are shown in Table 1. The kinematic viscosity and low calorific value were determined according to ASTM D240 and ASTM D445, respectively.
Fuel samples preparation
The miscibility of methanol and diesel should be
Spray characteristics
The fuel spray is very important, and the process has an essential influence on the combustion and emission characteristics of diesel engines. Thus, it is very necessary to investigate the spray process of diesel/methanol/n-butanol blends at different loads. Fig. 7 shows the in-cylinder fuel distribution field of diesel engine fueled with diesel/methanol/n-butanol blends at 100%, 50% and 25% loads.
According to the in-cylinder fuel distribution field, the oil beam and alcohol fuel significantly
Conclusions
With the continuous deterioration of energy crisis [66], [67], [68], [69] and environmental problems [70], [71], [72], finding effective methods to optimize the combustion of internal combustion engine and reduce emission has become the research focus. Methanol is a promising diesel additive because of its good physical properties. The low boiling point can improve the volatility of the blended fuel, and the high oxygen content can promote the rapid combustion of the blended fuel. With the
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper
Acknowledgments
The work is supported by the Innovation training program for college students of Guangxi University of science and technology under the research grant of 202110594172; This work is supported by the Natural Science Foundation of Guangxi under the research grant 2018GXNSFAA281267 and 2018GXNSFAA294122; This research is supported by the Guangxi University of Science and Technology Doctoral Fund under the research grants of 20Z22, 20S04 and 21Z34.
References (72)
- et al.
Effects analysis on optimal microwave energy consumption in the heating process of composite regeneration for the diesel particulate filter
Applied Energy
(2019) - et al.
Effects of boiling heat transfer on the performance enhancement of a medium speed diesel engine fueled with diesel and rapeseed methyl ester
Appl Therm Eng
(2020) - et al.
Effects of low-level water addition on spray, combustion and emission characteristics of a medium speed diesel engine fueled with biodiesel fuel
Fuel
(2019) - et al.
NOx emission and thermal performances studies on premixed ammonia-oxygen combustion in a CO2-free micro-planar combustor
Fuel
(2020) - et al.
Visible-light photoredox-promoted desilylative allylation of a-silylamines: an efficient route to synthesis of homoallylic amines
Tetrahedron Lett
(2021) - et al.
The effects of Fe2O3 based DOC and SCR catalyst on the combustion and emission characteristics of a diesel engine fueled with biodiesel
Fuel
(2021) - et al.
NOx emission performance assessment on a perforated plate-implemented premixed ammonia-oxygen micro-combustion system
Chem Eng J
(2021) - et al.
Performance and emission evaluation of a marine diesel engine fueled by water biodiesel-diesel emulsion blends with a fuel additive of a cerium oxide nanoparticle
Energy Convers Manage
(2018) - et al.
Effect analysis on cold starting performance enhancement of a diesel engine fueled with biodiesel fuel based on an improved thermodynamic model
Appl Energy
(2019) - et al.
Ethanol-fueled low temperature combustion: a pathway to clean and efficient diesel engine cycles
Appl Energy
(2015)
Impact of N-2 dilution on combustion and emissions in a spark ignition CNG engine
Energy Convers Manage
Improvement of fuel economy of a direct-injection spark-ignition methanol engine under light loads
Fuel
Experimental study of the effect of engine parameters on ultrafine particle in diesel/methanol dual fuel engine
Fuel
Analysis of operating a diesel engine on biodiesel-ethanol and biodiesel-methanol blends
Energy
Effects of diesel injection pressure on the performance and emissions of a HD common-rail diesel engine fueled with diesel/methanol dual fuel
Fuel
Impact of aluminium oxide nanoparticles as an additive in diesel-methanol blends on a modern DI diesel engine
Appl Therm Eng
Application of biobutanol in advanced CI engines – a review
Fuel
Experimental investigation of butanol isomer combustion in Homogeneous Charge Compression Ignition (HCCI) engines
Appl Energy
High yield bio-butanol production by solvent-producing bacterial microflora
Bioresour Technol
Experimental study on performance and emissions of a high speed diesel engine fuelled with n-butanol diesel blends under premixed low temperature combustion
Fuel
Ignition and combustion characteristics of n-pentanol–diesel blends in a constant volume chamber
Appl Energy
Numerical research on effect of hydrogen blending fractions on idling performance of an n-butanol ignition engine with hydrogen direct injection
Fuel
Evaluation of engine combustion and exhaust emissions characteristics using diesel/butanol blended fuel
Appl Therm Eng
Performance tests of a diesel engine fueled with pentanol/diesel fuel blends
Fuel
Experimental investigation on combustion, noise, vibrations, performance and emissions characteristics of diesel/n-butanol blends driven genset engine
Fuel
Influence of butanol addition to diesel–biodiesel blend on engine performance and particulate emissions of a stationary diesel engine
Appl Energy
Fueling a stationary direct injection diesel engine with diesel-used palm oil–butanol blends – an experimental study
Energy Convers Manage
Effect of diesel–microalgae biodiesel–butanol blends on performance and emissions of diesel engine
Fuel
Investigation on combustion and emission characteristics of a common rail diesel engine fueled with diesel/n-pentanol/methanol blends
Energy
Numerical investigation of mixture formation and combustion in a hydrogen direct injection plus natural gas port injection (HDI + NGPI) rotary engine
Int J Hydrogen Energy
Effects of fatty acid methyl esters proportion on combustion and emission characteristics of a biodiesel fueled marine diesel engine
Energy Convers Manage
Effect of water injection on the knock, combustion, and emissions of a direct injection gasoline engine
Fuel
A numerical study on RCCI engine fueled by biodiesel/methanol
Energy Convers Manage
Detailed physical properties prediction of pure methyl esters for biodiesel combustion modeling
Appl Energy
Effect of swirl ratio on NG/diesel dual-fuel combustion at low to high engine load conditions
Appl Energy
Simultaneous reduction of nitric oxide and smoke opacity in TDI dual fuel engine fuelled with calophyllum-diesel blends and waste wood chip gas for modified inlet valve and injector nozzle geometry
Energy
Cited by (112)
The beneficial effect of lauric acid addition in nucleation stage on the soot catalytic combustion performance of cerium-manganese catalyst
2024, Journal of Environmental Chemical EngineeringImprovements of performance and emission characteristics of a diesel engine fueled with diesel/PODE<inf>3</inf>/n-butanol blended fuels by RSM-NSGA III in plateau environment
2024, Process Safety and Environmental Protection