Performance, emission and combustion characteristics of poon oil and its diesel blends in a DI diesel engine

Experimental tests have been carried out to evaluate the performance, emission and combustion characteristics of a diesel engine using Neat poon oil and its blends of 20%, 40%, and 60%, and standard diesel fuel separately. The common problems posed when using vegetable oil in a compression ignition engine are poor atomization; carbon deposits, ring sticking, etc. This is because of the high viscosity and low volatility of vegetable oil. When blended with diesel, poon oil presented lower viscosity, improved volatility, better combustion and less carbon deposit. It was found that there was a reduction in NO_x emission for Neat poon oil and its diesel blends along with a marginal increase in HC and CO emissions. Brake thermal efficiency was slightly lower for Neat poon oil and its diesel blends. From the combustion analysis, it was found that poon oil-diesel blends performed better than Neat poon oil.     

Effects of biodiesel on a DI diesel engine performance, emission and combustion characteristics

Experimental tests were investigated to evaluate the performance, emission and combustion of a diesel engine using neat rapeseed oil and its blends of 5%, 20% and 70%, and standard diesel fuel separately. The results indicate that the use of biodiesel produces lower smoke opacity (up to 60%), and higher brake specific fuel consumption (BSFC) (up to 11%) compared to diesel fuel. The measured CO emissions of B5 and B100 fuels were found to be 9% and 32% lower than that of the diesel fuel, respectively. The BSFC of biodiesel at the maximum torque and rated power conditions were found to be 8.5% and 8% higher than that of the diesel fuel, respectively. From the combustion analysis, it was found that ignition delay was shorter for neat rapeseed oil and its blends tested compared to that of standard diesel. The combustion characteristics of rapeseed oil and its diesel blends closely followed those of standard diesel.     

Combustion, performance and emission characteristics of a DI diesel engine fueled with ethanol-biodiesel blends

In this study, Euro V diesel fuel, biodiesel, and ethanol-biodiesel blends (BE) were tested in a 4-cylinder direct-injection diesel engine to investigate the combustion, performance and emission characteristics of the engine under five engine loads at the maximum torque engine speed of 1800 rpm. The results indicate that when compared with biodiesel, the combustion characteristics of ethanol-biodiesel blends changed; the engine performance has improved slightly with 5% ethanol in biodiesel (BE5). In comparison with Euro V diesel fuel, the biodiesel and BE blends have higher brake thermal efficiency. On the whole, compared with Euro V diesel fuel, the BE blends could lead to reduction of both NO_x and particulate emissions of the diesel engine. The effectiveness of NO_x and particulate reductions increases with increasing ethanol in the blends. With high percentage of ethanol in the BE blends, the HC, CO emissions could increase. But the use of BE5 could reduce the HC and CO emissions as well.     

Experimental study of the effects of vegetable oil methyl ester on DI diesel engine performance characteristics and pollutant emissions

Vegetable oil methyl ester (VOME) is produced through the transesterification of vegetable oil and can be used as biodiesel in diesel engines as a renewable, nontoxic, and potentially environmentally friendly fossil fuel alternative in light of growing concerns regarding global warming and increasing oil prices. This study used VOME fuels produced from eight commonly seen oil bases to conduct a series of engine tests to investigate the effects of VOME on the engine performance, exhaust emissions, and combustion characteristics. The experimental results showed that using VOME in an unmodified direct injection (DI) diesel engine yielded a higher brake specific fuel consumption (BSFC) due to the VOME fuel’s lower calorific value. The high cetane number of VOME also imparted a better ignition quality and the high intrinsic oxygen content advanced the combustion process. The earlier start of combustion and the rapid combustion rate led to a drastic increase in the heat release rate (HRR) and the in-cylinder combustion pressure (ICCP) during the premixed combustion phase. A higher combustion rate resulted in higher peaks of HRR and ICCP as well as near the top dead center (TDC) position. Thus, it was found that a diesel engine fueled with VOME could potentially produce the same engine power as one fueled with petroleum diesel (PD), but with a reduction in the exhaust gas temperature (EGT), smoke and total hydrocarbon (THC) emissions, albeit with a slight increase in nitrogen oxides (NO_x) emissions. In addition, the VOME which possesses shorter carbon chains, more saturated bonds, and a higher oxygen content also yields a lower EGT as well as reduced smoke, NO_x, and THC emissions. However, this is obtained at the detriment of an increased BSFC.     

Experimental study of the performance and emission characteristics of diesel engine using direct and indirect injection systems and different fuels

An experimental study of the performance and emission characteristics of diesel engine using direct and indirect injection combustion systems are carried out on a same model of two diesel engines fuelled with diesel and the blend of diesel and Chinese pistache biodiesel. The results show that the NO_x emissions from the indirect injection combustion system (ICS) fuelled with diesel are reduced by around two thirds, compared to that from direct injection combustion system (DCS). Smoke emissions from the engine using ICS are all significantly lower than that of DCS, reduced by 70% for diesel; by 50-60% for the blend. The brake thermal efficiencies (BTEs) reduced by 8-10%, compared to that of DCS; the fuel consumptions increased by around 7-9%. It is also found that carbon monoxide (CO) emissions are reduced when the engine run at engine high power outputs, so are the hydrocarbon (HC) emissions from ICS at the peak power outputs. It is found that, when fuelled with the blend, the effects of ICS to the performance and emissions of diesel engine are very similar to that of running with diesel. For ICS engine fuelled with diesel and the blend fuel, the BSFCs for the blend are around 5% higher; the BTEs are around 2-4% lower; the reductions of NO_x from the blend fuel are 5.1-8.4% on average for the ICS; the reductions of smoke from the blend fuel are 26.8-31.7% on average for the ICS. CO emissions are around a half lower; and HC emissions are around one fifth lower, compared to that of fuelling with diesel. Comparing to that of DCS fuelled with diesel, using ICS fuelled with the blended fuel has much lower emissions. NO_x emissions decreased by 65.6% and 66.1%; smoke emissions decreased by 75.7% and 80.2%; CO emissions decreased by 55.8% and 46.0%; HC emissions decreased by 24.9% and 18.9%; with the BSFCs around 14.6-14.9% higher and the BTEs around 9.7-10.0% lower.     

Experimental investigation of diesel engine performance and emission characteristics using jojoba/diesel blend and sunflower oil

Experimental study has been carried out to investigate performance parameters, emissions, cylinder pressure, exhaust gas temperature (T_exhaust) and engine wall temperatures (T_wall) for direct injection diesel engine. Tests were conducted for sunflower oil (S100) and 20% jojoba oil + 80% pure diesel fuel (B20) in comparison to pure diesel fuel with different engine speeds. S100 and B20 were selected for the study because of its being widely used in Egypt and in the world. Also, series of tests are conducted at same previous conditions with different percentage of exhaust gas recirculation (EGR) from 0% to 12% of inlet mass of air fresh charge. Results indicate that S100 or B20 gives lower brake thermal efficiency (η_B), brake power (BP), brake mean effective pressure (BMEP), and higher brake specific fuel consumption (BSFC) due to lower heating value compared to pure diesel fuel. S100 or B20 gives lower NO_X concentration due to lower gas temperature. S100 or B20 gives higher T_wall and T_exhaust due to incomplete combustion inside engine cylinder. S100 or B20 gives higher CO and CO₂ concentrations due to higher carbon/hydrogen ratio. The position of maximum pressure (P_max) change for pure diesel fuel is earlier than for S100 or B20. The results show that S100 or B20 are promising as alternative fuel for diesel engine. The utilization of vegetable oils does not require a significant modification of existing engines. This can be seen as the main advantage of vegetable oils. The main disadvantages of biodiesel fuels are high viscosity, drying with time, thickening in cold conditions, flow and atomization characteristics.     

Numerical and experimental study of water/oil emulsified fuel combustion in a diesel engine

Numerical and experimental studies were made on some of the chemical and physical properties of water/oil emulsified fuel (W/OEF) combustion characteristics. Numerical investigations of W/OEF combustion's chemical kinetic aspects have been performed by simulation of water/n-heptane mixture combustion, assuming a model of a homogenous reactor's concentric shells. The injection and fuel spray characteristics are analyzed numerically also in order to study indirectly the physical effects of water present in diesel fuel during the combustion process. The experimental results of W/OEF combustion in the DI diesel engine are also presented and discussed. The results of engine testing in a broad field of engine loads and speeds have shown a significant pollutant emission reduction with no worsening of specific fuel consumption.     

Effect of altitude and palm oil biodiesel fuelling on the performance and combustion characteristics of a HSDI diesel engine

Altitude above sea level and fuel’s chemical and physical nature affect engine performance and combustion characteristics. In this work, a combustion diagnosis model including exergy analysis was applied to a turbocharged (TC) automotive diesel engine fuelled with neat palm oil biodiesel (B100) and No. 2 diesel fuel (B0). Tests were performed under steady state operating conditions, at two altitudes above sea level: 500 and 2400 m. Biodiesel fuelling and altitude had an additive effect on the advance in injection and combustion timings. The duration of the premixed combustion stage increased with altitude and decreased with biodiesel. When B100 was used, the transition between this stage and the diffusion stage was practically suppressed. As altitude increased, biodiesel fuelling led to shorter combustion duration, and higher in-cylinder pressures and fuel-air equivalence ratios. Brake thermal efficiency decreased with altitude for both fuels, but in a greater extent for B0. For all fuels and altitudes, exergy destruction rose sharply when combustion started, indicating that this process was the main source of irreversibilities. At both altitudes, the cumulative exergy destruction was higher for B100 due to its earlier and faster combustion process. Some of the results obtained in this work indicate that palm oil biodiesel fuelling can lead to a better engine performance at high altitudes.     

Utilization of unattended methyl ester of paradise oil as fuel in diesel engine

Engine tests have been carried out with the aim of obtaining the performance, emission and combustion characteristics of a diesel engine running on methyl ester of paradise oil (MEPS) and its diesel blends. From the emission analysis it was found that there was a significant reduction in smoke and hydrocarbon emissions by 33% and 22% respectively for MEPS 50 blend and 40% and 27% reductions for MEPS 100. However, there was an increase of 5% and 8% NO_x emission for MEPS 50 and MEPS 100 respectively. Brake thermal efficiencies of MEPS and its diesel blends are slightly lower than that of std. diesel. From the engine analysis, it was found that the performance of MEPS and its diesel blends were similar to that of std. diesel.     

A comparative study on the performance, emission and combustion studies of a DI diesel engine using distilled tyre pyrolysis oil–diesel blends

Alternate fuels like ethanol, biodiesel, LPG, CNG, etc., have been already commercialised in the transport sector. In this context, pyrolysis of solid waste is currently receiving renewed interest. The disposal of waste tyres can be simplified to a certain extent by pyrolysis. In the present work, the crude tyre pyrolyisis oil (TPO) was desulphurised and then distilled through vacuum distillation. Also, two distilled tyre pyrolysis oil (DTPO)–diesel fuel (DF) blends at lower and higher concentrations were used as fuels in a four stroke single cylinder air cooled diesel engine without any engine modification. The results were compared with diesel fuel (DF) operation. Results indicate that the engine can run with 90% DTPO and 10% diesel fuel.     

Influence of ethanol blends on the combustion performance and exhaust emission characteristics of a four-cylinder diesel engine at various engine loads and injection timings

The aim of this work is to investigate the effect of ethanol blending to diesel fuel on the combustion and exhaust emission characteristics of a four-cylinder diesel engine with a common-rail injection system. The overall spray characteristics, such as the spray tip penetration and the spray cone angle, were studied with respect to the ethanol blending ratio. A spray visualization system and a four-cylinder diesel engine equipped with a combustion and emission analyzer were utilized so as to analyze the spray and exhaust emission characteristics of the ethanol blending diesel fuel. Ethanol blended diesel fuel has a shorter spray tip penetration when compared to pure diesel fuel. In addition, the spray cone angle of ethanol blended fuels is larger. It is believed that the lower fuel density of ethanol blended fuels affects the spray characteristics. When the ethanol blended fuels are injected around top dead center (TDC), they exhibit unstable ignition characteristics because the higher ethanol blending ratio causes a long ignition delay. An advance in the injection timing also induces an increase in the combustion pressure due to the sufficient premixed duration. In a four-cylinder diesel engine, an increase in the ethanol blending ratio leads to a decrease in NO_x emissions due to the high heat of evaporation of ethanol fuel, however, CO and HC emissions increase. In addition, the CO and HC emissions exhibit a decreasing trend according to an increase in the engine load and an advance in the injection timing.     

A rapid test to measure performance,emission and wear of a diesel engine fueled with palm oil diesel

Results of performance, emission and tribological evaluations of palm oil methyl ester and its blends with conventional diesel in an automobile diesel engine test bed are presented. Polymerization and carbon deposits on the fuel injector were monitored. CO, CO₂, O₂, combustion efficiency and temperature of exhaust gases were also measured. Palm oil methyl ester and its blends have great potential as alternative diesel fuel. Performance and exhaust gas emission for palm oil methyl ester and its blends with conventional diesel are comparable with those of conventional diesel fuel. Palm oil methyl ester does not pose a severe environmental problem and will not deteriorate engine and bearing components.     

Combustion performance and emissions of petrodiesel and biodiesels based on various vegetable oils in a semi industrial boiler

This paper intends to investigate combustion of petrodiesel and biodiesels of grape seed, corn, sunflower, soybean, olive and rice bran oils, which were produced through an alkali-based transesterification, in a non-pressurized, water-cooled combustion chamber by determining its combustion performance and gas emissions (CO, CO₂, NO_x, SO₂). First, the influence of fuel pressure which related to the rate of sprayed fuel to the chamber was studied in order to find out an optimum combustion pressure. In the next level, the influence of A/F upon emissions and boiler performances at 13.79 bars was studied. Results show that similar combustion of fuels occurred at 13.79 bars (optimum) where due to the increase in fuel pressure, the effect of viscous forces in flame formation disappeared. Complete combustion of fuels occurred at 19.305 bars where the CO emissions of all the fuels reached to zero.The overall performance of the boiler obtained with the methyl esters and petrodiesel are comparable for the defined operating points (especially at high energy rates and low A/F). All the six kinds of vegetable based methyl ester emitted lower emissions than petrodiesel over the wide fuel pressures, and A/F. Meanwhile, biodiesels emitted higher amounts of NO_x than petrodiesel. Biodiesels also emitted higher amounts of CO than petrodiesel at low fuel pressures when the viscous forces interfered with proper distributions of fuels to the combustion chamber.     

Study of HCCI-DI combustion and emissions in a DME engine

HCCI combustion demonstrates the capability of simultaneously reducing NO_x and PM emissions and having a high brake thermal efficiency. However, there are still many challenges such as combustion control to overcome before full HCCI operation can be used reliably over the full engine operation range. Recently, the HCCI-DI compound combustion concept is presented, which is a compromise to full HCCI in that only a portion of the fuel is premixed and a portion of combustion is still controlled by the direct injection timing. Investigations towards HCCI-DI combustion in a DME engine were carried out in this paper. HCCI engine performances were presented to make a comparison. The peak in-cylinder pressure and the maximum heat release rate for HCCI-DI were lower than those for HCCI combustion and they decreased with a decrease in port DME aspiration quantity. Moreover, combustion duration was longer for HCCI-DI combustion and it would elongate with a decrease in port DME aspiration quantity. Engine experimental results showed HCCI-DI combustion could extend the operating range with a comparatively high brake thermal efficiency in comparison to HCCI combustion. CO and HC emission for HCCI-DI were lower than those of HCCI engine. As for NO_x emissions for HCCI-DI operation, it decreased remarkably at low loads with an increase in port DME aspiration quantity, while showed an increasing trend at high loads. To control the ignition and combustion phase of HCCI, the effect of cooled EGR on HCCI-DI was evaluated. As a result, NO_x emission decreased and the engine’s operating range enlarged for HCCI-DI combustion with cooled EGR.     

Performance,emission and combustion studies of a DI diesel engine using Distilled Tyre pyrolysis oil-diesel blends

Increase in energy demand, stringent emission norms and depletion of oil resources led the researchers to find alternative fuels for internal combustion engines. Many alternate fuels like Alcohols, Biodiesel, LPG, CNG etc have been already commercialized in the transport sector. In this context, pyrolysis of solid waste is currently receiving renewed interest. The disposal of waste tyres can be simplified to some extent by pyrolysis. The properties of the Tyre pyrolysis oil (TPO) derived from waste automobile tyres were analyzed and compared with the petroleum products and found that it can also be used as a fuel for compression ignition engine. However, the crude TPO has a higher viscosity and sulphur content. The crude TPO was desulphurised and then distilled through vacuum distillation. In the present work, DTPO-diesel blends were used as an alternate fuel in a diesel engine without any engine modification. This paper presents the studies on the performance, emission and combustion characteristics of a single cylinder four stroke air cooled DI diesel engine running with the Distilled Tyre pyrolysis oil (DTPO).     

An experimental investigation on a DI diesel engine using waste plastic oil with exhaust gas recirculation

Environmental degradation and depleting oil reserves are matters of great concern around the globe. Developing countries like India depend heavily on oil import of about 125 Mt per annum (7:1 diesel/gasoline). Diesel being the main transport fuel in India, finding a suitable alternative to diesel is an urgent need. In this context, waste plastic solid is currently receiving renewed interest. Waste plastic oil is suitable for compression ignition engines and more attention is focused in India because of its potential to generate large-scale employment and relatively low environmental degradation. The present investigation was to study the effect of cooled exhaust gas recirculation (EGR) on four stroke, single cylinder, direct injection (DI) diesel engine using 100% waste plastic oil. Experimental results showed higher oxides of nitrogen emissions when fueled with waste plastic oil without EGR. NO_x emissions were reduced when the engine was operated with cooled EGR. The EGR level was optimized as 20% based on significant reduction in NO_x emissions, minimum possible smoke, CO, HC emissions and comparable brake thermal efficiency. Smoke emissions of waste plastic oil were higher at all loads. Combustion parameters were found to be comparable with and without EGR. Compression ignition engines run on waste plastic oil are found to emit higher oxides of nitrogen.     

Engine performance, exhaust emissions and combustion characteristics of a CI engine fuelled with croton megalocarpus methyl ester with antioxidant

The use of biodiesel as a substitute for petroleum-based diesel has become of great interest for the reasons of combating the destruction of the environment, the price of petroleum-based diesel and dependency on foreign energy sources. But for practical feasibility of biodiesel, antioxidants are added to increase the oxidation stability during long term storage. It is quite possible that these additives may affect the clean burning characteristics of biodiesel. This study investigated the experimental effects of antioxidants on the oxidation stability, engine performance, exhaust emissions and combustion characteristics of a four cylinder turbocharged direct injection (TDI) diesel engine fuelled with biodiesel from croton megalocarpus oil. The three synthetic antioxidants evaluated its effectiveness on oxidation stability of croton oil methyl ester (COME) were 1, 2, 3 tri-hydroxy benzene (Pyrogallol, PY), 3, 4, 5-tri hydroxy benzoic acid (Propyl Gallate, PG) and 2-tert butyl-4-methoxy phenol (Butylated Hydroxyanisole, BHA). The fuel sample tested in TDI diesel engine include pure croton biodiesel (B100), croton biodiesel dosed with 1000 ppm of an effective antioxidant (B100 + PY1000), B20 (20% croton biodiesel and 80% mineral diesel) and diesel fuel which was used as base fuel. The result showed that the effectiveness of the antioxidants was in the order of PY > PG > BHA. The brake specific fuel consumption (BSFC) of biodiesel fuel with antioxidants decreased more than that of biodiesel fuel without antioxidants, but both were higher than that of diesel. Antioxidants had few effects on the exhaust emissions of a diesel engine running on biodiesel. Combustion characteristics in diesel engine were not influenced by the addition of antioxidants in biodiesel fuel. This study recommends PY and PG to be used for safeguarding biodiesel fuel from the effects of autoxidation during storage. Overall, the biodiesel derived from croton megalocarpus oil can be utilized as partial substitute for mineral diesel.     

Palm oil methyl esters as lubricant additive in a small diesel engine

Malaysian crude palm oil has been successfully converted to methyl esters, also known as palm oil diesel (POD), which is readily combustible in diesel engines. This paper presents and discusses the results of current studies on the performance and the effects of POD on the wear characteristics of tribological components of a small, four-stroke diesel engine. Adding POD to commercial lubricating oil has enhanced the performance of such oils. Results obtained from this study show that the power output and brake specific fuel consumption of the engine, lubricated with commercial SAE 40 oil blended with POD, are comparable to those of 100% SAE 40 oil. Wear debris analysis shows that blends of POD and SAE 40 commercial lubricating oil increase the anti-wear characteristics of the engine when compared to 100% SAE 40 lubricating oil.     

Effect of alternative fuels on exhaust emissions during diesel engine operation with matched combustion phasing

The present work focuses on an experimental comparison of diesel emissions produced by three fuels: an ultra low sulfur diesel fuel (BP15), a pure soybean methyl-ester biodiesel fuel (B100), and a synthetic Fischer-Tropsch fuel (FT), practically free of sulfur and aromatic compounds, and produced in a gas-to-liquid process. The study was carried out using a 2.5 L direct injection common-rail turbodiesel engine operated at 2400 rpm and 64 N m torque (19% of maximum torque). The engine was tested with single and split (pilot and main) injections and without exhaust gas recirculation (EGR). The study has two objectives. The first objective is to investigate the impact of the start of injection (SOI) on performance and emissions of each fuel. The second objective is to study the isolated impacts of the test fuels on pollutant emissions by adjusting the injection parameters (SOI and fuel rail pressure) for each fuel, while producing practically the same combustion phasing. When the combustion phasing occurs similarly, this study has confirmed that the FT fuel can reduce all regulated diesel emissions under both single and split injection strategies. Finally, it has been confirmed that biodiesel can reduce particle mean diameter in comparison with BP15. However, higher PM mass emission for B100 has been observed under the condition of matched combustion phasing. The increase of the PM mass emission is probably due to the unburned or partially burned hydrocarbon (HC) emissions.     

Effect of EGR and injection timing on combustion and emission characteristics of split injection strategy DI-diesel engine fueled with biodiesel

In this study, the effect of injection timing and EGR rate on the combustion and emissions of a Ford Lion V6 split injection strategy direct injection diesel engine has been experimentally investigated by using neat biodiesel produced from soybean oil. The results showed that, with the increasing of EGR rate, the brake specific fuel combustion (BSFC) and soot emission were slightly increased, and nitrogen oxide (NO_x) emission was evidently decreased. Under higher EGR rate, the peak pressure was slightly lower, and the peak heat release rate kept almost identical at lower engine load, and was higher at higher engine load. With the main injection timing retarded, BSFC was slightly increased, NO_x emission was evidently decreased, and soot emission hardly varied. The second peak pressure was evidently decreased and the heat release rate was slightly increased.