Earlier investigations by the authors revealed that a blend of 80% Jatropha methyl ester (JME) and 20% Tyre pyrolysis oil (TPO) referred to as JMETPO20 blend exhibited a better performance and lower emissions compared to other JMETPO blends [1]. Being a fuel derived from a non-petroleum source, the original injection timing of diesel engine may not be suitable for the blend. In this study, the influence of the injection timing on the combustion, performance and emission characteristics of a single cylinder, four stroke, air cooled, constant speed, direct injection (DI), naturally aspirated diesel engine has been experimentally investigated, when the engine was run with the JMETPO20 blend. The original injection timing was altered by adjusting the number of shims fitted under the plunger in the pump, by addition or removal of shims. In addition to the original injection timing of 23 °CA bTDC, other injection timings at which the study was carriedout were 20, 21.5, 24.5 and 26 °CA bTDC. The results indicated that the blend gave a better performance and lower emissions when operated with an advanced injection timing of 24.5 °CA bTDC as compared to other injection timings. At the advanced injection timing of 24.5 °CA bTDC, the maximum cylinder pressure was found to be higher by about 2.7 bar with a longer ignition delay, than that in case of the original injection timing at brake mean effective pressure (BMEP) of 5.6 bar. Further, the brake specific energy consumption (BSEC) decreased by about 7.1% compared to that of the original injection timing at BMEP of 5.6 bar. The carbon monoxide (CO), hydrocarbon (HC) and particulate emissions were also found to be reduced by about 14.2%, 13.26% and 9.3% respectively.

Combustion, performance and emission characteristics of a DI diesel engine fuelled with non-petroleum fuel: A study on the role of fuel injection timing

Spirulina microalgae biodiesel – A novel renewable alternative energy source for compression ignition engine

Experimental investigation of performance, exhaust emission and combustion parameters of stationary compression ignition engine using ethanol fumigation in dual fuel mode

Development in transport technology is a major issue owing to the increase the number of vehicles, which in turn increases emissions, which result in global warming. The world’s present transportation systems are greatly dependent on petroleum which will deplete rapidly due to limited reserves of fossil fuel. In addition, transportation is responsible for more than 25 percent of the world’s greenhouse gas (GHG) emissions, and this share is rising, which is a threat for future. As an alternative, biodiesel has drawn attention due to its renewability, biodegradability, high conductivity, low sulfur content, flash point, low aromatic content, increased lubricity etc. with less carbon monoxide and carbon dioxide emission. On the other hand, as the viscosity of biodiesel is greater than diesel due to its higher molecular mass and chemical structure, problems such as pumping, combustion, atomization in the injector system, injector deposit, plugging of filters, carbon deposits on piston and head of engine occur. Most previous studies concluded that although particulate emissions from biodiesel fuelled engines are much less than in gasoline, NOx emissions increases significantly. The adjustment of ignition delay in the premixed combustion phase, faster rate of fuel burn, advanced start of combustion, low radiation heat transfer and variable adiabatic flame temperature is mainly responsible for NOx formation and other emissions. Hence fuel additives may play an important role to counteract such problems and achieve various specified standards. Researchers have used many additives to improve the quality of biodiesel such as metal-based additives, oxygenated additives, cetane improvers, ignition promoters, cold-flow improvers, antioxidants and lubricity improvers etc. This literature review characterizes the combustion behavior of diesel engines fuelled by diesel, biodiesel and its blends including additives. It was found that combustion characteristics were improved by introducing additives into diesel and biodiesel blends, while exhaust emissions are also reduced.

A comprehensive review on the assessment of fuel additive effects on combustion behavior in CI engine fuelled with diesel biodiesel blends

In this investigation, the effects of adding small quantities of an ignition improver to a tyre derived fuel-diesel blend on the combustion, performance and emission parameters of a small powered, direct injection (DI) diesel engine have been evaluated. For this purpose, 40% light fraction pyrolysis oil (LFPO) obtained from a pilot level tyre pyrolysis plant blended with 60% diesel fuel, and designated as 40LFPO was used as a test fuel. The cetane number of 40LFPO was lesser than that of diesel, and hence, 1–4% Diethyl ether (DEE) was blended with it to improve the ignition quality. Four different 40LFPO-DEE blends denoted by X1, X2, X3 and X4 were tested in a single cylinder, four stroke, air cooled, DI diesel engine, with a developing power of 4.4 kW at 1500 rpm. The numeric value after the letter indicates the percentage of DEE in the blend. The experimental results were compared with those of diesel operation at different load conditions. The investigation results indicated that, the ignition delay was found to reduce with the 40LFPO blend as the percentage of DEE increased. The 4% DEE addition to 40LFPO (X4) gave better performance and lower emissions than those of X1, X2 and X3 at full load. The brake specific fuel consumption (bsfc) of X4 was lower by about 6% than that of diesel operation at full load. The NO emission of X4 was lower by about 25% than that of diesel operation at full load.

Effect of diethyl ether in a DI diesel engine run on a tyre derived fuel-diesel blend

In this study, combustion and emissions characteristics of a turbocharged compression ignition engine fueled with dimethyl ether (DME) and biodiesel blends are experimentally investigated. The effects of nozzle parameter on combustion and emissions are evaluated. The result shows that with the increase of DME proportion, ignition delay, the peak in-cylinder pressure, peak heat-release rate, peak in-cylinder temperature decrease, and their phases retard. Compared to the nozzle 6 × 0.40 mm, the peak cylinder pressure and peak heat-release rate are higher with nozzle 6 × 0.35 mm, and their phases are advanced. Increased DME proportion in fuel blends causes greater differences. Compared to biodiesel, NO x emissions of blends significantly decrease; HC emissions and CO emissions increase slightly. DME–biodiesel blends can be used as an alternative in a turbocharged CI engine. To obtain low NO x emissions and a soft engine operation, for high DME proportion blended fuels, nozzle of 6 × 0.40 mm adopted.

Study on combustion and emissions of a turbocharged compression ignition engine fueled with dimethyl ether and biodiesel blends

The injection rate and dynamic behaviour during and after the injection of dimethyl ether–biodiesel blends in a common-rail injection system are experimentally studied. The characteristics of the instantaneous line pressure evolution induced by the injection are obtained. In comparison with the injection of biodiesel, the injection of 100 wt % dimethyl ether starts later, but the starts of injection of other fuels are almost at the same time. Increasing the dimethyl ether blending ratio leads to a retarded end of injection and a significantly prolonged injection duration, but the peak injection rate changes little. With increasing rail pressure, the early rate of change in the injection rate with time and the peak injection rate increase, and the injection rate fluctuates more strongly. With increasing energizing time, the start of injection and the peak injection rate remain unchanged. The curves of the line pressure fluctuations at the injector inlet are similar for all dimethyl ether–biodiesel blends. When the dimethyl ether blending ratio is increased from 30 wt % to 100 wt %, the drop in the amplitude of the line pressure at the start of injection becomes smaller, the peak pressure decreases gradually and the phase is retarded. The duration of the line pressure fluctuations after injection becomes longer with increasing dimethyl ether blending ratio. By increasing the rail pressure, the line pressure at the start of injection drops more quickly, with a larger amplitude. At the end of injection, the magnitude of the peak pressure increases with an advanced phase, and the duration of the pressure fluctuations increases. By increasing the energizing time, the line pressure drop at the start of injection is unchanged, and the first line pressure peak increases with a retarded phase.

Experimental study on the injection characteristics of dimethyl ether–biodiesel blends in a common-rail injection system

The components of an aero-engine gas path cannot be monitored in a timely way due to a lack of real-time monitoring technologies. As an attempt to address this problem, we have conducted research on a condition monitoring technology based on the charging characteristics of particles in an aero-engine gas path, and emphatically analyze the formation of particles in an aero-engine gas path, the charging mechanism of carbon particles and the factors that influence the charge quantity and polarity. The verification experiments are performed on the simulated experiment platform and a turbo-shaft engine test bench. The results show the carbon particles’ carry charge, and an obvious change in the total electrostatic charge level in the aero-engine gas path due to the increased carbon particles produced by burning or abnormal metal particles; the charge number is related to the size of particles, and the bigger carbon particles carry a negative charge and metal particles carry a positive charge; the change in engine power can lead to an obvious change in the level of electrostatic charge in the gas path, and the change in electrostatic charge results from the extra carbon particles formed in the rich-oil burning process. The research provides a reference for establishing the baseline of electrostatic charge while the engine runs on different power. The study also demonstrates the validity of the electrostatic monitoring technology and establishes a base for developing the application of electrostatic monitoring technology in aero-engines.

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Formation Mechanism Analysis and Detection of Charged Particles in an Aero-engine Gas Path

This paper proposes a revised variation disturbance method to provide valuable information and reference for fuel design or optimization of internal combustion engines to realize the comprehensive and quantitative evaluation of the effects of blending agents on the combustion performance of primary fuels. In this method, methanol and ethanol are blended into gasoline to form six kinds of alcohol–gasoline (E10, E20, E30, M10, M20, and M30). Then, the ignition delay, adiabatic flame temperature, component concentration, fuel-burning rate, extinction strain rate, and CO emission of gasoline and alcohol–gasoline are studied by system simulation in a wide range of operating conditions. Based on the new variation disturbance method, the effects of methanol and ethanol on the combustion performance of gasoline are next analyzed globally and characterized quantitatively. The comprehensive results of ethanol and methanol on the gasoline’s combustion are visually presented. The method proposed in this paper is preliminarily validated based on the analysis of the microscopic mechanism of combustion. The results show that the blending of ethanol and methanol has positive effects on gasoline combustion, and ethanol can rapidly ignite the gasoline in a wide range of operating conditions and is superior to methanol in terms of fuel combustion, stability, and pollutant discharge. Based on the treatment of simulated values of six combustion characteristics selected in this paper and the calculations of the variation disturbance method, the total disturbance values of ethanol and methanol to gasoline combustion are obtained as 0.8493 and 0.2605, respectively. That is, ethanol has a more significant effect on improving the combustion performance of gasoline than methanol. In addition, based on the analysis results of the combustion, it is found that the blending of ethanol enlarges the reaction of notable components in gasoline. This finding also proves the effectiveness and validity of the scientific method utilized in this paper.

Effects of Ethanol and Methanol on the Combustion Characteristics of Gasoline with the Revised Variation Disturbance Method

A two-cylinder, direct injection diesel engine was modified for a homogeneous charge compression ignition-direct injection (HCCI-DI) engine fueled with dimethyl ether. Effects of premixed ratio on HCCI-DI combustion characteristics were experimentally investigated. The results show that in HCCI-DI combustion, as premixed ratio Rp increases, the peak pressure increases and its phase advances gradually; the first peak of pressure rise rate increases and the second peak decreases, and their phase advances gradually. With the increase of Rp, the cool flame peak increases gradually, the peaks of premixed combustion and diffusion combustion decrease gradually. The in-cylinder pressure is decomposed using discrete wavelet transform, the details D1, D2, D3, D4, D5, and D6 are obtained. The relative energy value of pressure at D6, D5, and D4 decreases gradually. The same results are obtained at 0.32 MPa brake mean effective pressure (BMEP), 0.24 MPa BMEP, and 0.16 MPa BMEP. The combustion state plays an important role in determining wavelet relative energy distribution of in-cylinder pressure over details. With increases of Rp, the energy value of in-cylinder pressure at D6 increases gradually, but the energy value at D5 and D4 decreases. It transforms from at D4 and at D5, to at D6 with the increase of Rp.

Effects of premixed ratio on combustion characteristics of a homogeneous charge compression ignition-direct injection engine fueled with dimethyl ether

Zhenhua Wen

Papers

Study on combustion and emissions of a turbocharged compression ignition engine fueled with dimethyl ether and biodiesel blends

Experimental study on the injection characteristics of dimethyl ether–biodiesel blends in a common-rail injection system

Formation Mechanism Analysis and Detection of Charged Particles in an Aero-engine Gas Path

Effects of Ethanol and Methanol on the Combustion Characteristics of Gasoline with the Revised Variation Disturbance Method

Effects of premixed ratio on combustion characteristics of a homogeneous charge compression ignition-direct injection engine fueled with dimethyl ether