Introduction
Motivation
Diesel engines play a crucial role in global transportation, manufacturing, power generation, construction, and agriculture However, the exhaust emissions from these engines significantly contribute to environmental pollution Additionally, recent petroleum crises have led to soaring oil prices, prompting stricter emission standards for compression ignition (CI) engines This creates increasing challenges for both the engine and petroleum industries to meet future regulatory requirements.
As emissions standards tighten to reduce diesel engine exhaust and fuel consumption, research is increasingly focusing on innovative engine technologies, after-treatment systems, and modifications to diesel fuel Incorporating oxygenate fuels, which contain small amounts of molecular oxygen, has emerged as an effective strategy for achieving cleaner-burning diesel and meeting stringent emission requirements Studies suggest that emissions levels are influenced by the oxygen content and are closely linked to the physical and chemical properties of these oxygenates.
The concept of using vegetable oils as fuel for diesel engines dates back to the early 20th century when research on renewable diesel fuels began In 1938, Walton conducted groundbreaking work on vegetable oils, proposing an early version of biodiesel His studies showed that these oils could be used in diesel engines with an efficiency comparable to modern engines, consuming 0.416 lb/bhp-hr of fuel However, the oils were prone to forming carbon deposits and had issues with low pour points Due to these challenges, Walton recommended breaking down triglycerides to utilize the resulting fatty acids as a viable fuel alternative.
Biodiesel is a renewable fuel made from long-chain fatty acids and alcohol, typically sourced from vegetable oils or animal fats The production process involves transesterification, where vegetable oil reacts with methyl or ethyl alcohol in the presence of a catalyst, resulting in biodiesel and glycerin.
Figure I.1 Simple representation of the transesterification reaction [34]
Recent studies indicate that biodiesel exhibits properties similar to those of diesel fuel, allowing it to be used in diesel engines with minimal or no modifications Biodiesel boasts a higher cetane number than petroleum diesel, contains fewer aromatics, and consists of 10% to 12% oxygen by weight These attributes contribute to reduced engine exhaust emissions, including carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM), particularly when biodiesel is blended with conventional diesel fuel The elevated oxygen content in biodiesel enhances combustion efficiency by increasing the oxygen available in fuel-rich areas of the combusting fuel spray.
Figure I.2 Average emission impacts of Biodiesel fuels in CI engines [20]
Replacing petroleum with biodiesel significantly reduces greenhouse gas emissions, particularly CO2 Plants absorb CO2 from the atmosphere during their growth, and when the oil is extracted and converted into biodiesel, it releases CO2 upon combustion However, this process does not contribute to an increase in net CO2 levels, as subsequent plant crops utilize the CO2 for their growth, creating a sustainable cycle.
Biodiesel and its blends are associated with higher NOx emissions compared to conventional diesel fuel, as evidenced by various studies The formation of engine deposits, particularly in combustion chamber components like the cylinder head, pistons, valves, and injectors, is exacerbated by an increase in unsaturated bonds within the fuel's molecular structure Recent data suggest that these deposits contribute to elevated NOx emissions due to their low thermal conductivity, especially non-volatile deposits like ash, which lead to increased in-cylinder temperatures.
Numerous studies have investigated the performance and exhaust emissions of Direct-Injection (DI) engines fueled by biodiesel derived from various sources, such as soybean, palm oil, and coconut oil However, research focusing on the use of Jatropha Curcas L oil or biodiesel produced from Jatropha Curcas L oil remains limited.
Research conducted at Institut Teknologi Bandung and other institutions, including studies by Sopheak R., Vaitilingom et al., Pramnik K., and Forson F.K et al., indicates that Jatropha Curcas L (JC) oil typically leads to higher exhaust gas emissions, including NOx, HC, CO, and Bosch Smoke number, compared to diesel fuel, with the extent of these emissions varying by engine type Additionally, a report from Kyushu Electric Power Company, Ltd highlights that using JC oil in diesel engines results in significantly greater injector tip coking and deposits on pistons and cylinder heads, leading to piston ring sticking after prolonged use, in contrast to diesel fuel.
Research from Institut Teknologi Bandung and other institutions highlights the potential of biodiesel derived from Jatropha Curcas L oil as a sustainable energy source Studies by Reksowardojo et al indicate that biodiesel blends, particularly B10, demonstrate superior thermal efficiency—8.47% higher—and significantly lower exhaust emissions compared to traditional diesel fuel Specifically, emissions of carbon monoxide (CO) and particulate matter are reduced by 80.85% and 72.67%, respectively Additionally, Nguyen N.D found that using biodiesel blends (B10, B20, B50) in a Yanmar Single Cylinder Industrial Diesel Engine resulted in negligible changes in engine power and torque, with reductions of less than 2% The research also revealed that biodiesel blends lead to lower hydrocarbon (HC) emissions, decreasing by 35% to 63%, while nitrogen oxides (NOx) emissions increased by 2.8% to 26.9% Both studies suggest that the best performance for direct injection diesel engines is achieved with B10 biodiesel blends, balancing economic and technological considerations.
Recent studies conducted at Institut Teknologi Bandung and other institutions have primarily concentrated on the use of biodiesel and its blends in stationary Direct Injection (DI) diesel engines However, there is a noticeable gap in research regarding the application of biodiesel and its blends in automotive diesel engines, specifically Indirect Injection diesel engines.
This study investigates the impact of biodiesel and its blends derived from JC oil on the performance and emissions of an automotive indirect injection diesel engine, comparing these effects to conventional diesel fuel Emissions tests are performed on a Toyota Kijang 2L engine, which features a prechamber design and is a four-cylinder, naturally aspirated model This engine is prevalent in light-duty diesel vehicles and passenger cars across Indonesia and ASEAN countries, representing a significant portion of the vehicles in this category.
Objectives
This research aims to assess the impact of biodiesel and its blends on an automotive IDI diesel engine, comparing these effects with those of locally sourced commercial diesel fuel The study involves a series of experiments designed to evaluate performance and efficiency.
1) To determine influences of increasing weight percent Biodiesel in the fuels on engine performance
2) To determine influences of increasing weight percent biodiesel in the fuels on engine exhaust emissions
3) To compare the optimum Biodiesel blend fuel (choosing from results of performance and exhaust gas emissions test) for deposit and cleanliness test with Diesel fuel.
Methodology
The first part concerns familiarization with the literature This involves basic theory on diesel engine and background of using Biodiesel fuel
The second phase of this research involves preparing biodiesel fuel from Jatropha Curcas L oil at the Laboratory of Production Unit Specific test procedures were designed and selected for targeted objectives, with the experimental setup conducted at the Laboratory of Internal Combustion Engine and Propulsion System Data collected during the experiment were thoroughly analyzed.
Outline
This thesis comprises six chapters, beginning with an overview of the research in Chapter I Chapter II outlines the fundamental theories underlying the study, while Chapter III details the experimental setup and procedures The results and discussions related to performance and exhaust gas emissions are presented in Chapter IV, followed by an examination of deposit cleanliness in Chapter V Finally, Chapter VI concludes with the research findings and recommendations.
Basic Theory
Background on Diesel Technology
The development of the internal combustion engine began in the late eighteenth century Slow but steady progress was made over the next hundred years By
In 1892, Rudolf Diesel patented a compression ignition reciprocating engine, initially designed to run on coal dust, which proved unsuccessful However, he later experimented with liquid petroleum by-products, discovering that diesel oil was a more effective fuel This pivotal shift, along with mechanical design improvements, led to a successful prototype engine in 1895 Today, both the engine and the fuel continue to carry Diesel's name.
There are two main types of Diesel engines: Direct Injection (DI) and Indirect Injection (IDI) In DI Diesel engines, fuel is injected directly into the combustion chamber, while IDI Diesel engines inject fuel into a prechamber connected to the cylinder This design allows for rapid air transfer and effective fuel-air mixing, leading to combustion in the prechamber that generates high pressure and shear forces Although IDI Diesel engines are less efficient and consume more fuel than their DI counterparts, they are still utilized in smaller vehicles like cars and light trucks due to their ability to operate across a wider speed range Additionally, their lower exhaust emissions make them suitable for urban areas where emission standards are a priority, despite the trade-off of higher fuel consumption with low annual mileage The IDI Diesel engine's pintle nozzle design also makes it less sensitive to fuel quality.
II.1.2 Mechanisms of Pollutant Formation in Diesel Engines
Diesel engines operate with a lean air-fuel mixture and high compression ratios, leading to superior thermal efficiency compared to gasoline engines At equivalent torque levels, diesel engines emit lower CO2, HC, and CO emissions However, the presence of locally fuel-rich regions in the combustion chamber results in increased levels of nitrogen oxides (NOx) and particulate matter (PM), which are significant air pollutants associated with diesel engines Consequently, diesel PM has become a major contributor to air pollution, prompting stricter regulatory measures.
Figure II.1 Schematic diagram of Dec’s conceptual DI Diesel engine controlled combustion model showing mixing controlled combustion, before the end of injection [9]
The formation of NOx is dependent on temperature, local Oxygen concentration and duration of combustion It is produced in a series of reactions such as the Zeldovich mechanism:
Engine exhaust gas emissions exhibit NOx concentrations that exceed predictions made by equilibrium thermodynamics, as the elimination of NOx occurs more slowly than its formation This rapid process prevents the system from achieving equilibrium.
The formation of nitrogen oxides (NOx) increases significantly with higher flame temperatures, suggesting that slightly rich mixtures could lead to elevated NOx concentrations However, this is not entirely accurate, as the flame speed also plays a critical role Lean mixtures, while having lower flame speeds, provide more time for NOx formation to occur.
In a diesel engine, the combustion process is characterized by a diffusion flame, where injected fuel mixes with charge air, creating a wide range of equivalence ratios Within the fuel spray, liquid fuel exists as droplets, while regions with equivalence ratios below unity are also present The flame typically occurs in an intermediate region where the equivalence ratio equals unity, leading to varying rates of NOx production based on local equivalence ratios, resulting in an averaging effect.
Lower engine speeds tend to increase NOx emissions for a specific power output because the reactions have more time to occur However, enhancing the injection rate can decrease NOx production by shortening the duration of diffusion-controlled combustion.
Oxidation of the Hydrocarbons up to CO 2 requires a number of elementary steps, which involve the radicals resulting form Oxygen and Hydrocarbons and which generate incomplete oxidation products:
In a diesel engine, three primary sources contribute to hydrocarbon (HC) emissions The first source is the lean zone at the edge of the reaction zone, where the mixture is too lean to combust effectively; reducing ignition delay can mitigate these emissions, as it naturally decreases with increased load, leading to cleaner combustion Additionally, advancing injection timing can elevate peak temperature and pressure, further lowering HC emissions The second significant source of HC emissions arises from fuel that remains in the injector nozzle sac after injection, which later enters the combustion chamber and creates a fuel-rich mixture that is not completely burned.
A significant contributor to excessive hydrocarbon (HC) emissions is over fueling, which occurs when there is insufficient air for complete fuel combustion This incomplete burning not only leads to increased HC emissions but also produces black smoke The shift from acceptable combustion to over fueling is noticeable, with HC emissions rising sharply as the equivalence ratio exceeds 0.9.
The formation of CO is an essential intermediate step in the hydrocarbon oxidation process leading to the final product CO2:
RH⇒ ⇒ 2 ⇒ ⇒ ⇒ where R represents the hydrocarbon radical The CO formed is then oxidizes at a slower rate to CO2 by the reaction:
The oxidation rate depends on available Oxygen concentrations, the temperature of the gases, and the time left for the reaction to take place, that is on the engine speed
The fuel–air ratio is a crucial factor influencing CO emissions In a rich mixture, higher fuel–air ratios lead to increased CO concentrations due to insufficient oxygen and incomplete combustion Conversely, in a lean mixture, CO concentrations remain low and fluctuate only slightly with changes in the fuel–air ratio, primarily due to incomplete oxidation occurring during the expansion phase.
Hydrocarbons desorbed from the deposits, the oil films, or crevices of the combustion chamber [5]
Diesel engines operate on a lean fuel mixture, resulting in significantly lower carbon monoxide (CO) emissions compared to gasoline engines However, the unevenness of the mixture, characterized by local oxygen deficiencies, varying temperature levels, and insufficient combustion time, can lead to CO emissions, particularly at low loads and high-speed maximum loads.
Diesel engines produce black smoke primarily due to carbon particles formed from the thermal cracking of large hydrocarbon fuel molecules during the diffusion combustion phase This process occurs on the rich side of the flame front, leading to the agglomeration of carbon particles that are visible in the exhaust While some particles are oxidized when they reach the lean side of the reaction, more oxidation occurs during the expansion stroke after the diffusion flame has extinguished To minimize smoke production, it is essential to shorten the duration of diffusion combustion, which can be achieved by increasing swirl, enhancing the injection rate, and utilizing a finer spray Advancing the injection timing also allows for more oxidation during the expansion stroke, further reducing smoke emissions.
Increased load leads to higher smoke production due to richer combustion, prolonged diffusion combustion time, elevated temperatures, and decreased oxidation during the expansion stroke This is a result of an extended diffusion phase and lower oxygen concentration Additionally, factors that influence hydrocarbon (HC) emissions also contribute to excessive smoke by raising the HC ratio.
Background on Biodiesel Technology
II.2.1 Biodiesel fuel from Jatropha Curcas L oil
Jatropha Curcas L., commonly known as Jarak Pagar, belongs to the Euphorbiaceae family and thrives in tropical regions This resilient plant is well-adapted to challenging soil and climate conditions, typically growing to a height of 3 to 5 meters Notably, it can produce an impressive annual seed yield of up to 5 tons per hectare in tropical environments.
JC tree, also known as Jatropha Curcas L., is traditionally utilized for medicinal purposes and as hedges It has been noted for its effectiveness as green manure in rice cultivation, particularly in loamy acidic soils However, it's important to note that Jatropha Curcas L oil is unsuitable for food consumption due to the presence of a toxic protein known as toxalbumin.
“curcine” and the presence of various toxic phorbol esters, for some of which the structure has recently been elucidated
Jatropha Curcas L is a valuable plant that produces seed oil high in oleic and linoleic acids, making it a promising feedstock for biodiesel production Research on the fuel properties of both methyl and ethyl Jatropha oil has shown encouraging results Various projects are currently underway globally, including initiatives in Indonesia at ITB and Lombok.
Research indicates that a kernel of JC contains approximately 35-55% oil, with the extraction yield varying based on the extraction method and seed quality The two primary oil extraction methods are chemical and mechanical extraction At ITB, a simple mechanical ram-press was utilized for the oil extraction process As illustrated in Figure II.2, processing 13 kg of seeds yielded 3 liters (2.7 kg) of JC oil.
Figure II.2 Flow chart of the Jatropha Curcas oil extraction process using the mechanical ram-press
The oil obtained was filtered and immediately utilized in the transesterification process, as illustrated in Figure II.3 The pure biodiesel derived from Jatropha Curcas L oil was produced using our continuous reactor at the Laboratory of the Production Unit.
Department of Chemical Engineering, ITB
Figure II.3 Biodiesel Processing Unit 600L/day at ITB [34]
The chemical, physical and fuel parameters of Biodiesel fuel from Jatropha
Curcas L oil were determined and compared with Diesel fuel (Table II.1)
Table II.1 Properties of Biodiesel fuel from Jatropha Curcas L oil and Diesel fuel
Lower Heating Value kJ/kg 43.099 39.530
The all of fuel parameters of Methyl Ester JC oil meet the specifications for Biodiesel of the world and Indonesia (Table II.2)
Table II.2 Summary of National standard for Biodiesel and Biodiesel blends [4]
(2006) Density kg/L 0.86 - 0.90 - 0.85 - 0.89 Kinematic Viscosity, 40 0 C mm 2 /sec 3.5 - 5.0 1.9 - 6.0 2.3 - 6.0 Cetane Number 51 min 47 min 51 min Flash Point 0 C 120 min 130 min 100 min Copper Strip Corrosion
Class No.1 No.3 max No.3 max
Carbon Residue % mass 0.30 max 0.05 max 0.30 max Water and sediment % vol - 0.05 max 0.05 max Distillation Temp
Ash content % mass 0.02 max 0.02 max 0.02 max Sulfur content ppm-mass
Acid value mg KOH/g 0.50 max 0.80 max 0.80 max Free Glycerol % mass 0.02 max 0.02 max 0.02 max Total Glycerol % mass 0.25 max 0.24 max 0.24 max Ester Content % mass 96.5 min - 96.5 min Iodine Value %-mass
II.2.2 Properties of Methyl Ester Jatropha Curcas L oil
II.2.2.1 Chemical Composition and Properties
The conventional fuel used in diesel engines contains higher amounts of aromatics and sulfur, which cause environment pollution As an example, higher amount of
Fossil-fueled diesel engines emit pollutants such as PM, HC, NOx, CO2, and SOx, while biodiesel, which contains about 10.99% mass oxygen, promotes more complete combustion This higher oxygen content leads to fewer unburned fuel emissions and enhances the hydrogen-to-carbon (H/C) ratio, which has been shown in some studies to reduce soot production.
Biodiesel is a cleaner alternative to petroleum-derived diesel, as it has lower aromatic content and is free of sulfur While petroleum diesel contains 20% to 40% aromatic compounds, studies show that minimizing poly- and mono-aromatic hydrocarbons can significantly reduce peak flame temperatures during combustion This reduction in temperature subsequently decreases the formation rates of nitrogen oxides (NOx) and particulate matter (PM).
During combustion, sulfur is transformed into sulfur dioxide (SO2), sulfur trioxide (SO3), and sulfate compounds, both in gas and solid form These solid sulfate particles increase the mass of soot and particulate matter (PM) Consequently, reducing sulfur content results in a decreased formation rate of soot and PM.
Besides, the chemical composition of the Methyl Ester JC oil presents in Table
II.3 The total saturated and unsaturated fatty acid compositions of B100 were
The composition of the fuel analyzed shows that it contains 43.0% monounsaturated fats, including Palmitoleic, Oleic, and Icosenoic acids, and 33.9% polyunsaturated fats, primarily Linoleic and Linolenic acids Notably, Oleic and Linoleic acids are the most prevalent unsaturated acids, comprising 42.1% and 33.7%, respectively Engine manufacturers have raised concerns that fuels high in unsaturated fats may polymerize, leading to deposits on critical engine components such as injector nozzles, piston rings, and ring grooves.
Table II.3 Chemical composition of Methyl Ester JC oil made in Lombok [7]
Chemical composition Molecular Structure Composition
Table II.1 presents the cetane index for Diesel fuel and Methyl Ester JC oil, indicating that Diesel fuel has a cetane number of 51.5, while Biodiesel exhibits approximately 11.84% higher performance with a cetane number of 57.6 A decrease in the Cetane Number (CN) results in a longer ignition delay, which subsequently increases emissions of hydrocarbons (HC), particulate matter (PM), and carbon monoxide (CO), alongside a rise in nitrogen oxides (NOx), although NOx emissions are less sensitive to changes in CN Notably, higher cetane numbers in conventional Diesel fuel have been linked to reduced NOx exhaust emissions.
Operating a diesel engine on biodiesel typically leads to a slight increase in NOx exhaust emissions, despite the high cetane number (CN) of fatty compounds Research indicates that the structure of fatty esters affects exhaust emissions, with NOx emissions rising alongside increased unsaturation and reduced chain length, which also relates to the CN of these compounds However, particulate matter (PM) emissions are largely unaffected by these structural characteristics The relationship between CN and engine emissions is influenced by various factors, including engine technology Older engines with lower injection pressures are particularly sensitive to CN, where higher CN results in significant reductions in NOx emissions due to shorter ignition delays and lower average combustion temperatures In contrast, modern engines with advanced injection systems that regulate injection rates show less sensitivity to changes in CN.
Table II.1 shows that diesel fuel has a density of 0.83, while Methyl Ester JC oil has a density of 0.866 Higher fuel density is associated with increased particulate matter (PM) and nitrogen oxides (NOx) emissions across all engine operating conditions, as indicated in Table II.4 This increase in fuel density also leads to higher fuel consumption and reduced power output, since mechanical injection systems deliver a fixed volume per crank angle, resulting in shorter injection durations when fuel density rises.
Biodiesel's boiling curves significantly affect engine performance and emissions As illustrated in Figure II.5, the boiling curves of Methyl Ester JC oil demonstrate a consistent rise in distillation temperature, resulting in a nearly horizontal line This higher boiling range of biodiesel is associated with a gradual dilution of lubricating oil by combusted fuel, leading to increased smoke emissions and higher levels of unburned hydrocarbons in exhaust gases.
Diesel Fuell Methyl Ester JC oill
Figure II.4 Comparison of average boiling curves for Diesel fuel and Methyl Ester
Fuel consumption is directly related to the volumetric energy density of the fuel, as indicated by the Lower Heating Value (LHV) According to Table II.1, Diesel fuel has a heating value of approximately 42.043 kJ/kg, while Methyl Ester JC oil, or Biodiesel, has a heating value that is roughly 6.86% lower than that of Diesel.
Viscosity plays a crucial role in the performance of diesel and biodiesel, significantly affecting components like the fuel pump and injection nozzle Increased viscosity can result in poor fuel atomization and incomplete combustion, leading to coking of injector tips and higher emissions of hydrocarbons (HC) and carbon monoxide (CO), while nitrogen oxides (NOx) emissions may decrease Notably, the viscosity of B100 biodiesel is higher compared to conventional diesel, which can influence its operational efficiency.
Summary
Biodiesel contains 10% to 12% oxygen by weight, and the addition of oxygenates alters its characteristics, including chemical composition, sulfur content, cetane number, fuel density, heat of combustion, kinematic viscosity, and distillation temperatures, compared to conventional diesel fuels These variations significantly impact the performance and emissions of diesel engines Changes in fuel structure, density, and viscosity affect the fuel system, leading to modifications in engine performance and exhaust emissions Additionally, alterations in cetane number, distillation temperature, and viscosity influence ignition delay, spray pattern, and heat release rates, ultimately affecting the combustion process and emissions.
Table II.4 Impact of Biodiesel Properties on Diesel Engine Emissions [2,5]
Experimental Set-up and Procedures
Experimental Procedures
The performance and exhaust gas emissions of a test engine were analyzed using five types of fuels: pure Biodiesel (100% Methyl Ester JC oil), standard Diesel fuel, and blends containing 10%, 20%, and 50% volumes of Methyl Ester.
Ester JC oil is produced using a stirred tank reactor in our Laboratory of Production Unit, where we also analyze the characteristics of blended fuels The properties of these fuels, determined by the volume fraction of Biodiesel, are detailed in Table III.2.
Table III.2 Properties of Test Fuels
Lower Heating Value kJ/kg 43.099 42.742 42.385 41.315 39.530
H/C Ratio 1.91 - - - 1.94 a a - calculated assuming linear blending by volume fraction [19, 20]
Careful selection of engine test procedures is crucial, as engines release harmful substances based on load and speed To effectively compare engine exhaust emissions, specific testing protocols must be utilized For automobiles, it is essential to implement test cycles that accurately simulate both city and highway driving conditions The most commonly employed test cycles are vital for this evaluation.
This research aims to investigate the impact of Methyl Ester JC oil on the performance, exhaust emissions, and deposits in an automotive IDI diesel engine To achieve this, advanced experimental procedures have been meticulously developed, encompassing three distinct tests.
Prior to each test, the dynamometer undergoes calibration The engine is warmed up for 15 minutes while idling and under no load After each test, the engine speed is lowered to idle with no load for 5 minutes before shutting down.
The performance tests are conducted at 75 % of throttle with speed varying from
The performance test was conducted at engine speeds ranging from 1000 rpm to 3000 rpm in 250 rpm increments, as outlined in Table III.3 The objective of this test is to evaluate the impact of Biodiesel and its blends on engine performance compared to B00 Each test mode is maintained for 3 minutes to ensure stability, during which key performance parameters such as torque, power, fuel flow consumption, air flow consumption, and exhaust gas temperature are measured and documented.
Table III.3 Test modes of performance test
III.2.2.2 Exhaust Gas Emissions Test
Before conducting each test, the dynamometer and exhaust gas analyzer undergo calibration The engine is warmed up for 15 minutes while idling and unloaded After each test, the engine speed is decreased to idle without load for 5 minutes before it is turned off.
The emissions test is conducted at 2000 rpm with Brake Mean Effective Pressures (BMEP) of 100 kPa, 200 kPa, 300 kPa, 400 kPa, 450 kPa, and 500 kPa to assess the impact of Methyl Ester JC oil on engine performance Key parameters such as exhaust gas temperatures, NOx, CO, HC, and smoke emissions are measured after each test mode, which lasts for 5 minutes to ensure stability Measurements are recorded during the final minute, and each fuel is tested three times to calculate an average value.
Table III.4 Test modes of engine exhaust emissions
III.2.2.3 Deposit and Cleanliness Test
Before testing, the cylinder head mating surface, piston crowns, piston rings, exhaust valves, and intake valves are thoroughly cleaned using a gasket scraper and gasoline The injectors, cleaned with solvent and fitted with new nozzles, are prepared for each test Weighing the pistons, valves, and new nozzles is essential, along with measuring the fuel flow from the injectors Additionally, the spray patterns of the injectors with new nozzles are documented through photography Following these preparations, the test engine is reassembled, and the entire system undergoes calibration and verification.
This test evaluates the deposit formation on combustion chamber components and injector cleanliness between B10 and B00 fuels, following the procedures outlined in SAE paper 942010: “Diesel Fuel Detergent Additive Performance and Assessment.” Prior to testing, a 30-minute break-in run is performed, after which the test engine operates for 6 hours at 3000 rpm and 80 Nm Upon completion of each test, the engine speed is reduced to idle with no load for 5 minutes before stopping the engine.
End of The deposit and cleanliness test
After the test, the crankcase oil is drained, and the oil filter is removed However,
250 ml of sample is retained to analyze
The injectors are removed from the engine without removing the nozzles from the injectors The injectors are checked for fuel flow on the Injector Flow Bench for
The fuel pump of the test engine operated at 500 RPM for 300 strokes Following the flow check test, the nozzles were meticulously removed from the injectors to avoid disturbing any deposits The nozzles were subsequently weighed to analyze the results.
The cylinder head, pistons and valves, should be removed from the test engine After that, they are photographed and weighed.
Results and discussion of Performance and Emissions Test
Performance Test
This section presents the findings from engine performance tests conducted at 75% throttle, with speeds ranging from 1000 rpm to 3000 rpm in 250 rpm increments During each speed test, measurements of torque, power, speed, and fuel flow consumption were meticulously recorded.
The torque output of an engine using various biodiesel blends at a 75% throttle position demonstrates notable reductions compared to diesel fuel, with B10, B20, B50, and B100 showing decreases of 2.53%, 6.17%, 4.26%, and 5.57%, respectively These reductions can be attributed to the 11% oxygen content in biodiesel, which lowers the fuel's heating value, and its higher viscosity, leading to less effective atomization and combustion Additionally, the data indicates that the maximum torque output occurs at 1750 rpm, while the peak thermal efficiency is reached at 2000 rpm across all fuel types.
2000 rpm is the speed for best combustion for all of the Biodiesel fuels
At speeds under 2000 rpm, Biodiesel fuels exhibit significantly different torque outputs compared to diesel, but this difference diminishes at higher speeds due to the impact of oxygen content in Biodiesel.
Figure IV.1 Engine torque versus engine speed at 75 % of throttle
Figure IV.2 shows that the power outputs for Biodiesel fuels are less than that for diesel For B10, B20, B50 and B100, the average values are 2.05 %, 5.39 %, 4.26-
At speeds exceeding 2000 rpm, the power outputs of Biodiesel fuels closely match those of Diesel fuel, despite being 5.4% to 6.17% lower at lower speeds.
Figure IV.2 Engine power versus engine speed at 75 % of throttle
IV.1.3 Brake Specific Fuel Consumption
The brake specific fuel consumption (BSFC) results indicate that BSFC tends to increase with higher biodiesel concentrations in fuel blends This rise in BSFC is attributed to the lower heating value (LHV) and higher density of biodiesel Notably, the minimum BSFC values are observed at 2000 rpm, recorded at 306 g/kWh for one blend and 314 g/kWh for another.
The brake specific fuel consumption (BSFC) values for biodiesel blends B00, B10, B20, B50, and B100 are measured at 319 g/kWh, 334 g/kWh, and 345 g/kWh, respectively When compared to diesel fuel, the average BSFC for B10, B20, B50, and B100 are 2.64%, 4.03%, 8.99%, and 12.6% higher However, at engine speeds above 2000 rpm, the BSFC values for biodiesel and diesel are nearly identical, with the exception of B50 and B100.
Figure IV.3 Brake specific fuel consumption versus engine speed at 75 % of throttle
The variation of thermal efficiency to engine speed is shown in Figure IV.4 For all of the Biodiesel fuels, the maximum value of thermal efficiency is reached at
At 2000 rpm, the thermal efficiency of a diesel engine is inversely related to the brake-specific fuel consumption (BSFC) and the lower heating value (LHV) of the fuels used When operating at higher speeds, the BSFC of biodiesel fuels aligns closely with that of traditional diesel fuel, resulting in a marginally improved thermal efficiency compared to diesel.
T h er m al E ff ici en c y (% )
Figure IV.4 Thermal efficiency versus engine speed at 75 % throttle
At 2000 rpm, thermal efficiency increases with load, as illustrated in Figure IV.5 At the maximum load of 500 kPa, the thermal efficiency values are 25.14% for Diesel fuel, 25.39% for B10, 23.93% for B20, 24.42% for B50, and 24.47% for B100, indicating that B10 offers the highest efficiency among the tested fuels.
Brake Mean Effective Pressure (kPa)
T h er m a l E ffi ci en cy ( % )
Figure IV.5 Thermal efficiency as a function of engine load at 2000 rpm
The analysis reveals that B10 biodiesel is the optimal fuel choice across all speeds, as it closely matches the torque output, power output, thermal efficiency, and brake specific fuel consumption (BSFC) of traditional diesel fuel Notably, the efficiency of fuel energy conversion declines significantly when the biodiesel volume exceeds 10%, regardless of load and speed conditions.
Exhaust Gas Emissions Test
This section presents the findings from engine emission tests conducted at 2000 rpm, with Brake Mean Effective Pressure (BMEP) ranging from 100 kPa to 500 kPa The tests measured key emissions, including Nitrogen Oxides (NOx), Unburned Hydrocarbons (HC), Bosch Smoke Number, Carbon Monoxide (CO), and Exhaust Gas Temperature.
Biodiesel fuels consistently exhibit significantly lower exhaust gas temperatures compared to Diesel fuel, indicating earlier combustion This earlier ignition allows for an extended expansion phase, which enhances energy release from the hot combustion gases A key factor influencing exhaust gas temperatures is ignition timing; earlier ignition can raise combustion temperatures while simultaneously lowering exhaust gas temperatures due to prolonged expansion Additionally, biodiesel's higher cetane number contributes to shorter delay periods and faster burning rates, further reducing combustion temperatures and, consequently, exhaust gas temperatures.
The exhaust gas temperature rises with increased engine load, as illustrated in Figure IV.6 At low engine loads, the exhaust gas temperatures for biodiesel and diesel are comparable; however, significant differences emerge at intermediate and high loads.
Brake Mean Effective Pressure (kPa)
E xh au st G as T em p er at u re ( o C )
Figure IV.6 Exhaust gas temperature as a function of engine load at 2000 rpm
Biodiesel and its blends exhibit slightly higher NOx emissions compared to Diesel fuel across all loads, with an average increase ranging from 2.02% to 10.16% The B10 blend demonstrates the highest NOx emissions due to its superior thermal efficiency and combustion characteristics However, this increase is minimal at high loads, particularly at 450 kPa of Brake Mean Effective Pressure (BMEP) Three primary factors influencing NOx emissions include oxygen concentration, combustion temperature, and combustion duration.
At low load conditions, the NOx emissions from Biodiesel and Diesel fuels differ significantly, primarily because the start of combustion (SOC) for Biodiesel occurs earlier than for Diesel Additionally, the exhaust gas temperature of Biodiesel is comparable to that of Diesel under low load conditions.
At high load (above 450 kPa), there is almost no difference between Biodiesel and Diesel fuels, because SOC of Biodiesel fuels is the same as that of Diesel fuel
[14], and exhaust gas temperature of Biodiesel fuels is lower than that of diesel at low load (Figure IV.6)
Brake Mean Effective Pressure (kPa)
O x ide s of N it roge n ( ppm )
Figure IV.7 Oxides of Nitrogen as a function of engine load at 2000 rpm
The Unburned Hydrocarbon (HC) emissions decrease as the percent Biodiesel increases for all of the Biodiesel fuels (Figure IV.8) Reduction of HC is smallest for B100
Brake Mean Effective Pressure (kPa)
Figure IV.8 Unburned Hydrocarbon as a function of engine load at 2000 rpm
The reduction of hydrocarbon (HC) emissions is more pronounced under high load conditions compared to low load, primarily due to two factors Firstly, the oxygen content in fuels plays a significant role at high loads Secondly, the formation of HC occurs mainly during premixed combustion, which is affected by ignition delay; biodiesel fuels, in particular, result in a shorter ignition delay.
This study focuses on smoke emissions, with results indicating that the Bosch Smoke Numbers at various loads are significantly lower for Biodiesel fuels compared to Diesel fuel As the load increases, the disparity in Bosch Smoke Numbers becomes more pronounced, demonstrating a substantial reduction in smoke emissions from Biodiesel Specifically, the average Bosch Smoke Numbers for B10, B20, B50, and B100 are 10.62%, 20.35%, 31.86%, and 46.90% lower than that of Diesel fuel, respectively.
Brake Mean Effective Pressure (kPa)
Figure IV.9 Bosch Smoke Number as a function of engine load at 2000 rpm
Carbon Monoxide (CO) is a byproduct of hydrocarbon combustion, with emissions varying across different fuels Biodiesel fuels are particularly effective in reducing CO emissions due to their higher oxygen content, which enhances combustion efficiency in fuel-rich zones This oxygen presence accelerates the combustion process, especially under high-load conditions where the air-to-fuel ratio is significantly lower than the critical range of 1.2 to 1.4.
Brake Mean Effective Pressure (kPa)
Figure IV.10 Carbon Monoxide as a function of engine load at 2000 rpm
Brake Mean Effective Pressure (kPa)
Figure IV.11 Excess Air ratio as a function of engine load at 2000 rpm
Summary
Table IV.1 and Figure IV.12 highlight the average performance changes compared to Diesel fuel, showing that thermal efficiency reductions for B10, B20, B50, and B100 are 1.21%, 3.83%, 1.48%, and 2.07%, respectively Additionally, torque output decreases for these blends are 2.53%, 6.17%, 4.26%, and 5.57% lower than that of Diesel fuel Notably, B10, which consists of 10% Biodiesel and 90% Diesel, exhibits the least performance reduction.
Table IV.1 and Figure IV.12 demonstrate significant reductions in gas temperature, hydrocarbon (HC) emissions, smoke numbers, and carbon monoxide (CO) levels when using biodiesel fuels While all biodiesel blends show a marked decrease in emissions, it is important to note a slight increase in nitrogen oxides (NOx), particularly observed in the B10 blend.
P er ce n t ch a n g e i n em is si o n and pe rf or m a nce
NOx HC CO Smoke Thermal Eff Torque
Figure IV.12 Dependency in percentage changes of performance and emissions on
The study investigates the impact of biodiesel concentration in diesel blends on the emissions and performance of automotive IDI engines Key emissions analyzed include nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO), and smoke, measured through Exhaust Gas Emissions Tests Additionally, thermal efficiency and torque performance were evaluated during Performance Tests, highlighting the relationship between biodiesel content and engine output.
The performance and exhaust gas emission tests aim to identify the optimal Biodiesel blend for subsequent deposit, cleanliness, emissions, and performance evaluations The selection of the ideal blend relies on the performance and emissions data gathered from these specific tests.
As a result, B10 is chosen for further tests in deposit and cleanliness, which is described in the next chapter
Table IV.1 Percentage of change in performance and Exhaust Gas Emissions relative to Diesel fuel
Fuel NOx HC Smoke CO Thermal efficiency
B50 8.79 -37.17 -31.86 - 8.12 -1.48 -4.26 B100 7.26 -42.94 -46.90 -13.36 -2.07 -5.57 (NOx, HC, CO, and Smoke emissions are taken from the Exhaust Gas Emissions Test, whereas thermal efficiency and torque are taken from the Performance Test)
Results and Discussion of Deposit and Cleanliness Test
Deposit Test
At the end of the deposit and cleanliness tests, the cylinder head, pistons, exhaust valves, inlet valves, and injectors are removed from the engine, photographed, and weighed
Figure V.1 illustrates the carbon deposits on the cylinder heads for B00 and B10 fuels, revealing that the B00 cylinder head exhibits a darker coloration compared to the B10 cylinder head This indicates that the carbon deposits on the B10 cylinder head are significantly lower than those found on the B00 cylinder head.
Figure V.1 Cylinder heads of B10 fuel (lower row) compared to those of B00 fuel
(upper row) after 6-hour test
In Figure V.2, the color of B00 pistons is darker than that of B10 pistons In addition, deposit on B10 pistons is uniform, while deposit on the top surface of B00 pistons is not
Figure V.2 Pistons of B10 fuel (lower row) compared to B00 fuel (upper row) after
Average weight of accumulated deposit on pistons (including piston rings) is 0.7167 gram for B10 fuel, which is less than the value of 0.7645 gram for B00 (Figure V.3 and Table V.1)
Piston No.1 Piston No.2 Piston No.3 Piston No.4 Average
Figure V.3 Deposit weight of pistons for B10 fuel compared to B00 fuel after
Table V.1 Weight analysis of deposits on pistons after 6-hour test for two fuels
Fuel Piston No.1 Piston No.2 Piston No.3 Piston No.4 Average
“-“ Indicates the percent changes is less than B00 fuel
Figure V.4 illustrates thickness of deposit on piston crowns The thickness for B10 pistons is slightly larger than that for B00 The average difference in thickness is 3.23 % (Table V.2)
Piston No.1 Piston No.2 Piston No.3 Piston No.4 Average
Thi c k ne s s ( m ic rom e te r)
Figure V.4 Thickness of Pistons for B10 fuel compared to B00 fuel after 6-hour test
Table V.2 Thickness analysis of deposits on Pistons after 6-hour test for two fuels
Fuel Piston No.1 Piston No.2 Piston No.3 Piston No.4 Average
“-“ Indicates the percent changes is less than B00 fuel (thickness)
The analysis reveals that B10 intake valves exhibit a uniform flat carbon build-up, in contrast to the irregular carbon deposits found on the stem surfaces of B00 intake valves According to Table V.3, the average net weight of carbon deposits on B10 intake valves is significantly lower, measuring 42.83% less than that of B00 intake valves, as illustrated in Figure V.6.
Figure V.5 Intake valves of B10 fuel (lower row) as compared to B00 fuel (upper row) after 6-hour
Table V.3 Weight analysis of deposits on intake valves after 6-hour test for the two fuels
“-“ Indicates the percent changes is less than B00 fuel
Inlet Valve No.1 Inlet Valve No.2 Inlet Valve No.3 Inlet Valve No.4 Average
Figure V.6 Deposit weight of B10 intake valves as compared to that of B00 intake valves after 6-hour tests
In Figure V.7, the color of B00 Exhaust Valves is darker than that of B10 Exhaust Valves It means that deposit on B10 Exhaust Valves is less than that on B00 Exhaust Valves
Figure V.7 Exhaust valves of B10 fuel (lower row) compared to B00 fuel (upper row) after 6-hour tests
Table V.4 Weight analysis of exhaust valve deposits after 6-hour test for the two fuels
“-“ Indicates the percent changes is less than B00 fuel
Results of deposit weight analysis of Exhaust Valves after the test are shown in Table V.4 Average deposit weight of B10 Exhaust Valves is 79.69 % less than that of B00 Exhaust Valves
Figure V.8 Deposit weight of Exhaust valves for B10 fuel compared to B00 fuel after 6-hour tests
Exhaust Valve No.1 Exhaust Valve No.2 Exhaust Valve No.3 Exhaust Valve No.4 Average
Carbon deposits on injector tip nozzles were observed after a 6-hour test using B00 and B10 fuels, as illustrated in Figures V.9 and V.10 While the injector tips in these figures are not clearly visible for direct comparison, the quantitative results presented in Table V.5 and Figure V.11 indicate that B10 fuel significantly reduces injector coking in diesel engines.
Figure V.9 Injector nozzle coking of B10 fuel (lower row) compared to B00 fuel
(upper row) after 6-hour test
Figure V.10 Injector tip coking of B10 fuel (lower row) compared to B00 fuel (upper row) after 6-hour test
Table V.5 Weight analysis of deposits on injector tip after 6-hour test for the two fuels
Fuel Nozzle No.1 Nozzle No.2 Nozzle No.3 Nozzle No.4 Average
“-“ Indicates the percent changes is less than B00 fuel
Figure V.11 Deposit weight of Nozzles for B10 fuel (lower row) compared to
B00 fuel (upper row) after 6-hour test
During a 6-hour test, HC emissions from B10 fuel showed a significant reduction compared to B00 fuel Specifically, the average HC emissions for B10 were 54.97% lower than those of B00, indicating a marked improvement in emissions performance with the use of B10 fuel.
U nbu rne d H y dr oc a rbon ( ppm)
Figure V.12 Unburned Hydrocarbon for 6-hour test with B00 and B10 fuels
Figure V.13 shows that the CO emission of B10 and B00 fuels reduces during the 6-hour tests The results of CO emission of the two fuel kind are generally similar
In particular, the average value of CO emission for B10 fuel is 16.13 % lower than
Nozzle No.1 Nozzle No.2 Nozzle No.3 Nozzle No.4 Average
D e po s it We ight ( gr a m )
B00 B10 that of B00 fuel However, CO emission of B10 fuel increases slightly after 4 hours
C a rbon M on ox ide ( ppm ) B10 B00
Figure V.13 Carbon Monoxide during 6-hour test of B00 and B10 fuels
Injector Cleanliness Analysis
Figure V.14 illustrates the remaining fuel flow of B00 and B10 injectors in comparison to those with new nozzles The fuel flow volume of injectors with new nozzles was measured before the tests and again after a 6-hour testing period for both B00 and B10 nozzles The results indicate an average fuel flow volume loss of 4.11% for B00 injectors and 2.49% for B10 injectors when compared to their initial clean condition.
B10 fuel can manage injector fuel flow loss, typically ranging from 0.50% to 4.98% of the total fuel volume Despite this loss, the actual fuel flow volume shows an increase of 1.69% compared to B00 fuel, highlighting the improved efficiency of B10 fuel over traditional options.
Table V.6 Percent fuel flow loss of injectors after 6-hour test using the two fuels as compared to the injectors with new nozzles
Fuel Injector No.1 Injector No.2 Injector No.3 Injector No.4 Average B00 5.47 % 5.47 % 3.48 % 2.00 % 4.11 % B10 4.98 % 3.48 % 0.50 % 1.00 % 2.49 %
Injector No.1 Injector No.2 Injector No.3 Injector No.4 Average
F u el F lo w V o lu m e ( cc/ 300 st ro kes )
Injectors with new nozzles After using B00 After using B10
Figure V.14 Flow change in injectors before and after 6-hour test for B00 and B10 fuels
When introducing a new fuel, it is essential to examine the spray patterns of the combustion system, which are typically conical and uniformly distributed As illustrated in Figure V.15, the injectors maintain integrity by not leaking or dripping under a pressure of 100 bar for 30 seconds.
Figure V.15 Spray patterns of injectors after 6-hour test for the two fuels (upper row:
In fact, the high viscosity reduces fuel atomization and increases fuel spray penetration The results show that B10 fuel has about 0.5 % higher density and 4-
B10 fuel exhibits a higher viscosity compared to B00 fuel, leading to wider spray cones in B10 injectors, as illustrated in Figure V.16 The average spray-cone angles for B00 and B10 injectors are 88.35% and 92.75% of those with new nozzles, respectively (refer to appendix E for spray patterns of injectors with new nozzles) This indicates that the use of B10 fuel effectively reduces injector tip coking in diesel engines.
Figure V.16 Spray cones of injectors after 6-hour test for the two fuels (upper row:
Lube Oil Analysis
Viscosity is a critical property of lubricating oil, significantly influencing the wear rate of engine components High viscosity can lead to increased friction losses due to the shearing forces acting on the lubricant, hindering the formation of a protective film Additionally, during normal engine operation, lubricating oil often becomes diluted with fuel, especially during starting when a rich fuel-air mixture and low ambient temperatures are present This dilution reduces oil viscosity and compromises the oil's load-carrying capacity.
100 0 C after 6-hour test (Figure V.17) indicate that there is a great difference between the two fuels: 15.68 cSt for B10 fuel and 14.91 cSt for B00 fuel
Figure V.17 Viscosity of lubricating oil after 6-hour test for the two fuels
The impact of B10 and B00 fuels on Total Base Number (TBN) is illustrated in Figure V.18 TBN, which measures the alkalinity of oil, reflects its capacity to mitigate corrosive effects from oxidation Higher TBN values indicate greater stability in lubricating oil The data reveals that the TBN depletion for B10 fuel is slightly greater than that of B00, with values of 9.55 mgKOH/g for B10 and 9.53 mgKOH/g for B00, indicating a minor difference in their performance.
Figure V.18 Total Base Number in lubricating oil after 6-hour test for the two fuels
New Lube oil After using B10 After using B00
New Lube oil After using B10 After using B00
V isco si ty at 100o C ( cS t)
The analysis results show that engine wear is occurring at a normal rate, with total wear metal levels measuring 19 ppm for both B10 and B00 fuels, indicating no significant difference between the two fuel types.
Figure V.19 Total Wear Metals in lubricating oil after 6-hour test for the two fuels
Summary
The examination reveals no abnormal coking on the cylinder head, pistons, valve stems, or injectors Notably, after a 6-hour test, B10 fuel demonstrates a reduction in deposits on combustion chamber components compared to B00 fuel Additionally, the exhaust gas emissions for B10 fuel are significantly lower than those of B00 fuel, with reductions of 54.97% for hydrocarbons (HC) and 16.13% for carbon monoxide (CO).
The results show that the spray cones of B10 injectors are wider than those of B00 injectors
The analysis reveals that there is minimal difference in Total Base Number (TBN) and total wear metals between B10 and B00 fuels after a 6-hour test However, the viscosity of the lubricating oil for B10 fuel is 5% higher compared to B00 fuel.
T o ta l we a r m e ta ls ( p p m ) Pb
Conclusions and Recommendations
Conclusions
1 The automotive IDI diesel engine can be used with methyl ester JC oil and its blends without engine modification; there was no problem with the engine when the experiment was performed
2 Biodiesel and its blends are comparable with Diesel fuel in performance parameters, such as torque, power, BSFC, and thermal efficiency The difference is a few percents higher or lower, depending on parameter
3 Engine operation conditions (load and speed) affect performance and emissions
4 Methyl Ester JC oil and its blends help to reduce exhaust gas temperature, HC,
5 For Biodiesel and its blends, NOx were slightly higher than Diesel fuel However, the difference in NOx emissions is not significant
6 In the 6-hour test, B10 helps to reduce emissions of HC and CO, and deposit in combustion chamber Since using Biodiesel fuels results in 1.69% higher fuel flow volume than using Diesel fuel, life of engine injectors might be significantly longer
7 B10 can be used widely rather than the other blends, in consideration of engine performance, emissions, limited feedstock of Biodiesel fuel, and price of fuels.
Recommendations
1 This study contributes to the understanding on Biodiesel The procedures used in this research can be applied to research on other feedstock of Biodiesel fuel
2 Combustion phenomena should be monitored by pressure transducer and video-scope, which fully explains the formation of exhaust gas emissions in automotive IDI Diesel engine
3 In this research, we used Bosch Smoke Number to analyze the soot emission For better accuracy, Opacity Meter should be used to measure Particulates Matter (PM)
4 The procedures of this study are steady tests For future research, engine should run in transient tests
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Physical and Chemical properties of the test fuels
Table A.1 Diesel fuel Analysis Results
Table A.2 Methyl Ester JC Oil Analysis Results
Table A.3 Analysis Results of Methyl Ester JC Oil made in Lombok [7]
27 Water and Sediment, 60oC mg/100ml 0.1
Physical and Chemical properties of Lube oils
Table B.1 Analysis results of used lube oil after 6-hour test for Diesel fuel
Table B.2 Analysis results of used lube oil after 6-hour test for B10 fuel.
Results of Performance Test
Table C.1 Results of Performance Test of Diesel fuel
Table C.2 Results of Performance Test of B10 fuel
Table C.3 Results of Performance Test of B20 fuel
Table C.4 Results of Performance Test of B50 fuel
Table C.5 Results of Performance Test of B100 fuel
Results of Exhaust Gas Emissions Test
Table D.1 Results of Exhaust Gas Emissions Test of Diesel fuel
Table D.2 Results of Exhaust Gas Emissions Test of B10 fuel
Table D.3 Results of Exhaust Gas Emissions Test of B20 fuel
Table D.4 Results of Exhaust Gas Emissions Test of B50 fuel
Table D.5 Results of Exhaust Gas Emissions Test of B100 fuel
Table D.6 Summary results of Performance and Exhaust Gas Emissions Test of Biodiesel fuels
Smoke Number relatively to B00 fuel
Thermal Efficiency relatively to B00 fuel
Results of Deposit and Cleanliness Test
Table E.1 Results of Exhaust Gas Emissions for 6-hour test for Diesel fuel
Table E.2 Results of Exhaust Gas Emissions for 6-hour test for B10 fuel
Table E.3 Results of Deposit and Cleanliness Test for diesel fuel
Before test After test Before test After test Before test After test Before test After test
Cylinder No.1 Cylinder No.2 Cylinder No.3 Cylinder No.4
Piston weight, gram 612.7167 656.3500 615.6000 659.3500 611.0500 655.0167 615.5667 659.4167 Piston thickness, mm 0.0350 0.0450 0.0400 0.0350
Fuel flow for 300stroke at 500 rpm of the engine fuel pump, ml
20.1 19 20.1 19 20.1 19.4 20.1 19.7 Fuel flow loss after 6-hour test, % 5.4726 5.4726 3.4826 1.9900
Table E.4 Results of Deposit and Cleanliness Test for B10 fuel
Before test After test Before test After test Before test After test Before test After test Cylinder No.1 Cylinder No.2 Cylinder No.3 Cylinder No.4 Piston weight, gram 655.5833 656.1500 658.4000 659.2167 653.9500 654.8333 658.4500 659.0500
Fuel flow for 300stroke at 500 rpm of the engine fuel pump, ml 20.1 19.1 20.1 19.4 20.1 20 20.1 19.9
Fuel flow loss after 6-hour test, % 4.9751 3.4826 0.4975 0.9950