Combustion and Emissions Characteristics of a Polypropylene Blended Diesel Fuel in a Direct Injection Compression Engine

Author(s):  
Valentin Soloiu ◽  
Yoshinobu Yoshihara ◽  
Kazuie Nishiwaki ◽  
Yasufumi Nakanishi

The authors investigated the formulation, combustion and emissions of polypropylene (PP)–diesel fuel mixtures in a direct injection diesel engine. The fuel has been obtained by an original technology they developed, in which the low or high density polypropylene (LDPP, HDPP), have been mixed in a nitrogen atmosphere at 200 °C, 10–40% by wt. in diesel fuel. The kinematic viscosity of the polypropylene-diesel fuels was investigated between 25–250 °C and the results showed that viscosity of the plastic mixtures is much higher than that of diesel alone, ranging from 10 cSt to 500 cSt, and depending on the plastic structure, content, and temperature. The TGA and DTA analysis has been conducted to investigate the oxidation and combustion properties of pure PP and polymerdiesel fuels. The results showed that at about 125 °C, the LDPP melts, but does not decompose up 240 °C, when the oxidation starts, and has a peak of heat release at 340–350 °C, and the process is completed at 400 °C. The engine’s injection system used, was a piston-barrel type pump, capable of an injection pressure of 200 bars. The injector had 4 × 0.200 mm nozzles with a conical tip needle. The 25% PP-diesel mixture had a successful ignition in a direct injection 110 mm bore, omega combustion chamber engine. The ignition delay for polypropylene-diesel mixtures was longer by about 0.5 ms (at 1200 rpm), compared with diesel. The heat release showed a different development compared with the reference diesel fuel, the premixed phase being inhibited while a slow diffusion combustion phase fully developed. The maximum combustion pressure has been 83 bars for diesel and decreased by 2 bars for the blended fuel, while the bulk gas maximum temperature (calculated) reached about 2500 K for diesel vs 2600 K for polypropylene mixture. The heat flux calculated by the Annand model has shown lower values for diesel fuel with a maximum of about 2.7 MW/m2 compared with 3.0 MW/m2 for PP blended fuel with similar values for convection flux for both fuels at about 1.57 MW/m2 and a higher radiation flux of about 1.44 MW/m2 for PP fuel versus 1.27 MW/m2 for diesel. The heat lost during the cycle shows low values for the premixed combustion stage and increased values for the diffusion stage for both fuels. The exhaust temperatures have been practically identical for both fuels for all loads, with emissions of NOx, and CO reduced by 40% for the alternative fuel, while the CO2 exhibited almost the same values for both fuels. The smoke emissions decreased by 60–90% for the polypropylene blended fuel depending on the load, The engines’ overall efficiency was slightly lower for PP fuel at low loads compared with diesel combustion but at 100% load both reached 36%. The study showed that the new formulation process proposed by the authors is able to produce a new class of fuels from diesel blended with low density polypropylene, and resulted in hybrid fuels with very promising combustion prospects. The engine investigation proved that 25% PP fuels can be injected and burnt in a diesel engine at a residence time of about 5 ms from the start of injection, and the engine’s nominal power could be reached, with lower emissions than reference diesel fuel.

Author(s):  
Hyun Kyu Suh ◽  
Hyun Gu Roh ◽  
Chang Sik Lee

The aim of this work is to investigate the effect of the blending ratio and pilot injection on the spray and combustion characteristics of biodiesel fuel and compare these factors with those of diesel fuel in a direct injection common-rail diesel engine. In order to study the factors influencing the spray and combustion characteristics of biodiesel fuel, experiments involving exhaust emissions and engine performance were conducted at various biodiesel blending ratios and injection conditions for engine operating conditions. The macroscopic and microscopic spray characteristics of biodiesel fuel, such as injection rate, split injection effect, spray tip penetration, droplet diameter, and axial velocity distribution, were compared with the results from conventional diesel fuel. For biodiesel blended fuel, it was revealed that a higher injection pressure is needed to achieve the same injection rate at a higher blending ratio. The spray tip penetration of biodiesel fuel was similar to that of diesel. The atomization characteristics of biodiesel show that it has higher Sauter mean diameter and lower spray velocity than conventional diesel fuel due to high viscosity and surface tension. The peak combustion pressures of diesel and blending fuel increased with advanced injection timing and the combustion pressure of biodiesel fuel is higher than that of diesel fuel. As the pilot injection timing is retarded to 15deg of BTDC that is closed by the top dead center, the dissimilarities of diesel and blending fuels combustion pressure are reduced. It was found that the pilot injection enhanced the deteriorated spray and combustion characteristics of biodiesel fuel caused by different physical properties of the fuel.


Author(s):  
Vinay Nagaraju ◽  
Mufaddel Dahodwala ◽  
Kaushik Acharya ◽  
Walter Bryzik ◽  
Naeim A. Henein

Biodiesel has different physical and chemical properties than ultra low sulfur diesel fuel (ULSD). The low volatility of biodiesel is expected to affect the physical processes, mainly fuel evaporation and combustible mixture formation. The higher cetane number of biodiesel is expected to affect the rates of the chemical reactions. The combination of these two fuel properties has an impact on the auto ignition process, subsequently combustion and engine out emissions. Applying different swirl ratios and injection pressures affect both the physical and chemical processes. The focus of this paper is to investigate the effect of varying the swirl ratio and injection pressure in a single-cylinder research diesel engine using a blend of biodiesel and ULSD fuel. The engine is a High Speed Direct Injection (HSDI) equipped with a common rail injection system, EGR system and a swirl control mechanism. The engine is operated under simulated turbocharged conditions with 3 bar Indicated Mean Effective Pressure (IMEP) at 1500 rpm, using 100% ULSD and a blend of 20% biodiesel and 80% ULSD fuel. The biodiesel is developed from soy bean oil. A detailed analysis of the apparent rate of heat release (ARHR) is made to determine the role of the biodiesel component of B-20 in the combustible mixture formation, autoignition process, premixed, mixing controlled and diffusion controlled combustion fractions. The results explain the factors that cause an increase or a drop in NOx emissions reported in the literature when using biodiesel.


2021 ◽  
Vol 14 (1) ◽  
pp. 345
Author(s):  
Mostafa Kiani Deh Kiani ◽  
Sajad Rostami ◽  
Gholamhassan Najafi ◽  
Mohamed Mazlan

Contrary to energy, exergy may be destroyed due to irreversibility. Exergy analysis can be used to reveal the location, and amount of energy losses of engines. Despite the importance of the exergy analysis, there is a lack of information in this area, especially when the engine is fueled with biodiesel–diesel fuel blends under various injection operating parameters. Thus, in this research, the exergy analysis of a direct-injection diesel engine using biodiesel–diesel fuel blends was performed. The fuel blends (B0, B20, B40, and B100) were injected into cylinders at pressures of 200 and 215 bars. Moreover, the simulation of exergy and energy analyses was done by homemade code. The simulation model was verified by compression of experimental and simulation in-cylinder pressure data. The results showed there was good agreement between simulation data and experimental ones. Results indicated that the highest level of in-cylinder pressure at injection pressure of 215 bars is more than that of 200 bars. Moreover, by increasing the percentage of biodiesel, the heat transfer exergy, irreversibility, burnt fuel, and exergy indicator decreased, but the ratio of these exergy parameters (except for heat transfer exergy) to fuel exergy increased. These ratios increased from 46 to 50.54% for work transfer exergy, 16.57 to 17.97% for irreversibility, and decreased from 16 to 15.49% for heat transfer exergy. In addition, these ratios at 215 bars are higher than at 200 bars for all fuels. However, with increasing the injection pressure and biodiesel concentration in fuel blends, the exergy and energy efficiencies increased.


1999 ◽  
Vol 123 (1) ◽  
pp. 167-174 ◽  
Author(s):  
P. J. Tennison ◽  
R. Reitz

An investigation of the effect of injection parameters on emissions and performance in an automotive diesel engine was conducted. A high-pressure common-rail injection system was used with a dual-guided valve covered orifice nozzle tip. The engine was a four-valve single cylinder high-speed direct-injection diesel engine with a displacement of approximately 12 liter and simulated turbocharging. The engine experiments were conducted at full load and 1004 and 1757 rev/min, and the effects of injection pressure, multiple injections (single vs pilot with main), and pilot injection timing on emissions and performance were studied. Increasing the injection pressure from 600 to 800 bar reduced the smoke emissions by over 50 percent at retarded injection timings with no penalty in oxides of nitrogen NOx or brake specific fuel consumption (BSFC). Pilot injection cases exhibited slightly higher smoke levels than single injection cases but had similar NOx levels, while the single injection cases exhibited slightly better BSFC. The start-of-injection (SOI) of the pilot was varied while holding the main SOI constant and the effect on emissions was found to be small compared to changes resulting from varying the main injection timing. Interestingly, the point of autoignition of the pilot was found to occur at a nearly constant crank angle regardless of pilot injection timing (for early injection timings) indicating that the ignition delay of the pilot is a chemical delay and not a physical (mixing) one. As the pilot timing was advanced the mixture became overmixed, and an increase of over 50 percent in the unburned hydrocarbon emissions was observed at the most advanced pilot injection timing.


Author(s):  
Jim Cowart ◽  
Dianne Luning Prak ◽  
Len Hamilton

In an effort to understand the effects of injection system pressure on alternative fuel performance, a single cylinder diesel engine was outfit with a modern common rail fuel injection system and piezoelectric injector. As future new fuels will likely be used in both older mechanical injected engines as well as newer high pressure common rail engines, the question as to the sensitivity of a new fuel type across a range of engines is of concern. In this study conventional diesel fuel (Navy NATO F76) was compared with the new Navy HRD (Hydro-processed Renewable Diesel) fuel from algal sources, as well as the high cetane reference fuel nC16 (n-hexadecane CN=100). It was seen that in general, IGD (Ignition Delay) was shortened for all fuels with increasing fuel injection pressure, and was shortened with higher CN fuels. The combustion duration for all fuels was also significantly reduced with increasing fuel injection pressure, however, longer durations were seen for higher CN fuels at the same fuel pressure due to less pre-mixing before the start of combustion. Companion modeling using the LLNL (Lawrence Livermore National Lab) heavy hydro-carbon and diesel PRF chemical kinetic mechanisms for HRD and nC16 was applied to understand the relative importance of the physical and chemical delay periods of the IGD. It was seen that at low fuel injection pressures, the physical and chemical delay times are of comparable duration. However, as injection pressure increases the importance of the chemical delay times increases significantly (longer), especially with the lower CN fuel.


2008 ◽  
Vol 132 (1) ◽  
pp. 17-24
Author(s):  
Kazimierz LEJDA ◽  
Paweł WOŚ

In the paper the rate of heat release analysis in direct injection diesel engine has been presented and discussed. The research has been carried out for two different injection strategies, i.e. for conventional single-phase injection and for triple-phase injection executed by a Common Rail injection system. The calculation methodology of heat release rate based on indicator diagram has been presented as well.


Author(s):  
Seung Hyun Yoon ◽  
Sung Wook Park ◽  
Dae Sik Kim ◽  
Sang Il Kwon ◽  
Chang Sik Lee

A single cylinder DI (direct injection) diesel engine equipped with common-rail injection system was used to investigate the combustion and emission characteristics of biodiesel fuels. Tested fuels were conventional diesel and biodiesels obtained from unpolished rice oil and soybean oil. The volumetric blending ratios of biodiesel with diesel fuel are set at 0, 10, 20 and 40%. Experimental results show that the peak injection rate is reduced as the mixing ratio increased. The effect of the mixing ratio on the injection delay of biodiesel is not significant at the equal injection pressure. The peak combustion pressure was increased with the increase of the mixing ratio at an injection pressure of 100MPa. The ignition delay became shorter with the increase of the mixing ratio due to a higher cetane number of the biodiesel. HC and CO emissions are decreased at a high injection pressure. However, NOx emissions are increased at higher mixing ratios.


2010 ◽  
Vol 24 (15n16) ◽  
pp. 2850-2855 ◽  
Author(s):  
SEUNG-HUN CHOI ◽  
YOUNG-TAIG OH

In this study, the possibility of biodiesel fuel and oxygenated fuel (dimethoxy methane ; DMM) was investigated as an alternative fuel for a naturally aspirated direct injection diesel engine. The smoke emission of blending fuel (biodiesel fuel 90vol-% + DMM 10vol-%) was reduced approximately 70% at 2500rpm, full load in comparison with the diesel fuel. But, engine power and brake specific energy consumption showed no significant differences. But, NOx emission of biodiesel fuel and DMM blended fuel increased compared with commercial diesel fuel due to the oxygen component in the fuel. It was needed a NOx reduction counter plan that EGR method was used as a countermeasure for NOx reduction. It was found that simultaneous reduction of smoke and NOx emission was achieved with BDF (95 vol-%) and DMM (5 vol-%) blended fuel and cooled EGR method (15%).


2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Seung Hyun Yoon ◽  
Su Han Park ◽  
Hyun Kyu Suh ◽  
Chang Sik Lee

An experimental investigation was performed to analyze the effects of biodiesel-ethanol blended fuel spray on the combustion, and exhaust emission characteristics in a single cylinder common-rail diesel engine. In order to analyze the macroscopic and microscopic characteristics of biodiesel blended fuel spray, parameters, such as injection rate, droplet diameter, and spray tip penetration, were measured using an injection rate meter system, spray visualization, and droplet measuring system. Also, measurements of combustion, exhaust emissions, and size distributions of particulate matter were carried out under various engine operating conditions for biodiesel-ethanol blends and the results were compared with those of conventional diesel fuel. In this investigation, the measured results of biodiesel-ethanol blended fuel show that the Sauter mean diameter decreased with the increase of relative velocity between the injected fuel and the ambient gas. Comparing the combustion characteristics of diesel fuel and biodiesel-ethanol blended fuels, both diesel and blended fuel show similar trends of combustion pressure and rate of heat release. However, the combustion of biodiesel-ethanol blends indicated lower combustion characteristics, such as combustion pressures and heat release rates, than those of diesel fuel because of its lower heating value. In the case of exhaust gas recirculation, the indicated specific NOx(ISNOx) and soot concentration results showed lower emissions compared with those of conventional diesel fuel.


2005 ◽  
Vol 128 (3) ◽  
pp. 497-505 ◽  
Author(s):  
Dae Sik Kim ◽  
Myung Yoon Kim ◽  
Chang Sik Lee

In order to obtain the reduction effect of NOx and soot emission in a partial homogeneous charge compression ignition engine, premixed fuel was supplied with direct injection diesel fuel. Several additional systems such as a premixed fuel injection system, exhaust gas recirculation (EGR) system, supercharger, and air heating system were equipped in the intake manifold of conventional diesel engine. Premixed fuel with air was compressed and ignited by the directly injected diesel fuel in the combustion chamber at the end of compression stroke. The effect of premixed fuel on combustion and emission characteristics of HCCI diesel engine was investigated experimentally under various conditions of intake air temperature, pressure, and EGR rate. The results showed that in case of the use of gasoline as a premixed fuel, single stage ignition is found, but premixing the diesel fuel accompanies the cool flame prior to the combustion of the directly injected diesel fuel. For the gasoline premixed fuel, both NOx and soot can be reduced by the increase of premixed ratio simultaneously. However, for the diesel premixed fuel, the increase of premixed ratio does not have a significant effect in reducing the soot emission.


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