Common Rail Direct Injection Diesel Engine Research Articles

Improvement of NOX Reduction Rate of Urea SCR System Applied for an Non-Road Diesel Engine

Urea SCR technology has been widely used to reduce NOx emissions of diesel engines. Despite remarkable development for decades, more advanced control and optimization of urea SCR systems are still required as global NOx emissions standards are expected to become more stringent. This study investigated several influential parameters of urea SCR system to improve NOx reduction efficiency. This study uses a commercialized UWS (Urea Water Solution) supply system and a SCR catalyst which was installed in the exhaust line of a non-road CRDI (Common Rail Direct Injection) diesel engine. From this study, it was found that the low space velocity of SCR catalyst is essential for high NOx reduction efficiency, especially at low temperatures. Early injection of UWS enhances the overall NOx reduction efficiency if UWS injection was carefully controlled to avoid urea deposits. Rich injection of UWS with AOC is a good strategy for high NOx reduction efficiency. However, NOx reproduction in the AOC, which has an adverse effect on the overall NOx reduction rate, occurs at high exhaust gas temperatures. System insulation also can improve the NOx reduction efficiency by a few percentage points.

Influences of biodiesel fuels produced from highly degraded waste animal fats on the injection and emission characteristics of a CRDI diesel engine

In the current study, biodiesel fuels produced from waste chicken fat and waste fleshing oil with high free fatty acid were tested in a four stoke, four-cylinder, water-cooled, turbocharged-intercooled, common rail direct injection (CRDI) diesel engine. Their effects on the injection and exhaust emission characteristics of the test engine were determined and compared with those of petroleum-based diesel fuel (DF) as the reference fuel. Engine tests were performed at different engine loads and constant engine speed of 2000 rpm. Injection characteristics showed differences with respect to engine load and fuel type. However, the effects of biodiesel fuels on the injection profiles were more dominant for main injection characteristics such as the start of main injection, end of the main injection, injection amount and injection rate and these effects became more pronounced with increasing engine load. Compared to DF, animal fat based biodiesels had better total hydrocarbon (THC) and carbon monoxide (CO) emissions, but their carbon dioxide (CO2) and especially nitrogen oxides (NOx) emissions were higher. In addition, waste fleshing oil-based biodiesel fuel emitted lower emissions than waste chicken fat-based biodiesel.

Study of the Effects of Biofuel-Oxygen of Various Origins on a CRDI Diesel Engine Combustion and Emissions

The paper presents the effects made by a fossil diesel–HRD (Hydrotreated Renewable Diesel) fuel blend containing Ethanol (E) or Biodiesel (B) on the combustion process, Indicated Thermal Efficiency (ITE), smoke, and pollutant emissions when running a turbocharged Common Rail Direct Injection (CRDI) engine under medium (50% of full load), intermediate (80% of full load), and full (100%) loads at maximum torque speed of 2000 rpm. These loads correspond to the respective Indicated Mean Effective Pressures (IMEP) of 0.75, 1.20, and 1.50 MPa, developed for the most common operation of a Diesel engine. The fuel-oxygen mass content was identically increased within the same range of 0 (E0/B0), 0.91 (E1/B1), 1.81 (E2/B2), 2.71 (E3/B3), 3.61 (E4/B4), and 4.52 wt% (E5/B5) in both E and B fuel groups. Nevertheless, these fuels still possessed the same blended cetane number value of 55.5 to extract as many scientific facts as possible about the widely differing effects caused by ethanol or biodiesel properties on the operational parameters of an engine. Both quantitative and qualitative analyses of the effects made by the combustion of the newly designed fuels with the same fuel-oxygen mass contents of various origins on the engine operational parameters were conducted comparing data between themselves and with the respective values measured with the reference (‘baseline’), oxygen-free fuel blend E0/B0 and a straight diesel to reveal the existing developing trends. The study results showed the positive influence of fuel-oxygen on the combustion process, but the fuel oxygen enrichment rate should be neither too high nor too low, but just enough to achieve complete diffusion burning and low emissions. The Maximum Heat Release Rate (HRRmax) was 3.2% (E4) or 3.6% (B3) higher and the peak in-cylinder pressure was 4.3% (E3) or 1.1% (B5) higher than the respective values the combustion of the reference fuel E0/B0 develops under full load operation. Due to the fuel-oxygen, the combustion process ended by 7.3° (E4) or 1.5° crank angle degrees (CADs) (B4) earlier in an engine cycle, the COV of IMEP decreased to as low as 1.25%, the engine efficiency (ITE) increased by 3.1% (E4) or decreased by 2.7% (B3), while NOx emissions were 21.1% (E3) or 7.3% (B4) higher for both oxygenated fuels. Smoke and CO emissions took advantage of fuel-oxygen to be 2.9 times (E4) or 32.0% (B4) lower and 4.0 (E3) or 1.8 times (B5) lower, respectively, while THC emissions were 1.5 times (E4) lower or, on the contrary, 7.7% (B4) higher than the respective values the combustion of the fuel E0/B0 produces under full load operation. It was found that the fuel composition related properties greatly affect the end of combustion, exhaust smoke, and pollutant emissions when the other key factors such as the blended cetane number and the fuel-oxygen enrichment rates are the same in both fuel groups for any engine load developed at a constant (2000 rpm) speed.

Feasibility Analysis of Pyrolysis Waste Engine Oil in CRDI Diesel Engine

Abstract In this present investigation, microwave assisted pyrolysis (MAP) was carried out for converting waste engine oil into diesel-like fuel. The addition of susceptor enhanced the heating rate and decreased the power consumption of the pyrolysis. The specific energy consumption was four times lesser when the activated carbon mixed with waste engine oil by 40%. The maximum energy was recovered from the pyrolysis at 400°C with 1.1 kW power rating which is 15.75% higher than 2.2 kW power rating at the same temperature. The physicochemical properties of pyrolysis fuel were similar to diesel. The higher calorific value was noticed for pyrolysis oil by 2.4% compared to diesel fuel. The microwave pyrolysis oil (MPO) was tested in a single cylinder diesel engine using conventional injection and common rail direct injection (CRDI). The brake thermal efficiency of MPO was increased by 4.4% in CRDI compared to mechanical injection. The NO and smoke emission was decreased by 50% and 54% respectively in CRDI compared to mechanical injection. CRDI improves the atomization and increases the injection duration period leads to decrease of the heat release rate on the premixed stage of the combustion and also attained low peak pressure during the combustion. This study reveals that CRDI improves the combustion efficiency of pyrolysis fuel used in CI engine.

Optimization of Multiple Injection Strategy in Modified Common Rail Direct Injection Diesel Engine Powered with Palm Oil Methyl Ester

In this investigation, the common rail direct injection (CRDI) single cylinder four stroke diesel engine has made to modify in terms of toroidal reentrant combustion chamber (TRCC) shape and 7 holes CRDI nozzle injector. The current experimental study objective is to optimization of multiple injection strategy (MIS) in modified CRDI diesel engine powered with palm oil methyl ester (POME) B100 and diesel fuels. In the first phase of work, experiment results showed that slightly improved in brake thermal efficiency (BTE) and reduced emissions except oxides of nitrogen (NO_x) for POME fuelled engine operates under optimized MIS, fuel injection timing (IT) of -10° before top dead center (BTDC) and 600 bar injection pressure (IOP) in modified CRDI diesel engine. In the second phase of work, the performance of modified CRDI diesel engine is improved by increasing IOP from 600 bar to 900 bar at same MIS and fuel IT. The second phase of experiment results showed that percentage of increase in BTE by 2.47%, peak pressure (PP) by 13.69%, heat release rate (HRR) by 17.64%, NO_X by 11.70% and percentage of decreased in ignition delay (ID) by 29.62%, combustion duration (CD) by 13.79%, unburnt hydrocarbon (UBHC) by 19.04%, carbon monoxide (CO) by 14.28%, smoke level by 20.93% as compared to first phase of work in modified CRDI diesel engine fuelled with POME.

Application of Palm Oil Biodiesel Blends under Idle Operating Conditions in a Common-Rail Direct-Injection Diesel Engine

This study describes the effects of palm oil biodiesel blended with diesel on the combustion performance, emission characteristics, and soot morphology in a 4-cylinder common-rail direct-injection (CRDI) diesel engine. The operational condition is idle speed, 750 rpm (the lowest speed of the test engine without any operation by driver), and the load conditions of the engine are 0 Nm and 40 Nm. Five kinds of biodiesel fuels are blended with diesel in 0%, 10%, 20%, 30%, and 100% proportions by volume. A pilot injection was applied at BTDC 15 °CA and 20 °CA. Part of the pilot injection affects the combustion of the main injection due to the deterioration of the spray because of the high viscosity of palm oil biodiesel. Palm oil biodiesel is sufficient to keep the engine stable in an idling state, but the fuel economy deteriorated. The deterioration of the spray due to the high viscosity of palm oil biodiesel is offset by the effect of oxygen content and high cetane number, resulting in a constant nitric oxide (NOx) emission. However, particulate matter (PM) is reduced. When the engine load is increased, the carbon monoxide (CO) emission amount increased because of the insufficient intake air and oxygen content to reduce the fuel-rich areas. However, when the palm oil biodiesel blend ratio was above a certain level, the influence of oxygen content in the palm oil biodiesel increased, resulting in reduced CO emission levels. Hydrocarbon (HC) was reduced by oxygen atoms in palm oil biodiesel. The sizes of particulates emitted from diesel engine using palm oil biodiesel decreased with an increased blend ratio because of oxidization of hydrocarbons absorbed on PM.

Experimental investigations on the influence of higher injection pressures and retarded injection timings on a single cylinder CRDi diesel engine

ABSTRACT Improved engine exhaust emissions with little or no deterioration in performance may be achieved through the use of new technologies and/or modifying the engine hardware. Present paper details the attempts of an experimental evaluation of Kirloskar make TV1 type diesel engine equipped with common rail direct injection (CRDi) and electronic control unit (ECU). It is established that retarded injection timing and smaller fuel droplets simultaneously reduce NO x and smoke emissions of a typical diesel engine. Hence engine testing was carried out using diesel fuel at 1500 rpm, under 50–100% of full load brake power, at various retarded injection timings and higher injection pressures. Reduced ignition delay, improved combustion, and simultaneous reduction in oxides of nitrogen and smoke emissions with modest deterioration in performance are observed when the engine is operated at 500 bar injection pressure and at an injection timing of 16° before the top dead centre.

Performance and emission characteristic studies on CRDI diesel engine fuelled with plastic pyrolysis oil blended with ethanol and diesel

ABSTRACTThis paper mainly focuses on the utilisation of plastic pyrolysis oil (PPO) and its’ blends with diesel and ethanol in different proportions in a modified diesel engine fitted with common rail direct injection (CRDI) facility. PPO was subsequently blended with diesel and ethanol and characterisation has been done. Experiments were conducted to investigate the impact of injection timing (IT) and injection pressure (IP) on the performance of modified CRDI engine fuelled with PPO and its blends with diesel and ethanol. From the experimental investigations, IT of 10°bTDC and IP of 900 bar were found as best operating parameters to obtain maximum brake thermal efficiency (BTE) with lowered emissions for the fuel combinations utilised in the investigations. PPO as substitute to diesel fuel could be viable if its major concern is to finding permanent resources.

Experimental investigations on the performance and emission characteristics of a common rail direct injection engine using tyre pyrolytic biofuel

The ever increasing demand from the industry and transport sector has led to an increased requirement of diesel and other oil products. These fuels belong to the non-renewable resources, their continuous availability is uncertain for the future. These factors along with the political instability causes fluctuating prices and supply of diesel .These have an impact on developing countries like India which met majority of demand from the import. Different researchers have been working to find out bio-fuels to substitute for diesel in compression ignition engines. Several fuels like liquefied petroleum gas (LPG). Biodiesel, Alcohols and compressed natural gas (CNG) are substituted these days by different automobiles. Tyre pyrolytic oil is obtained by the pyrolysis of waste tyres.Tyre pyrolytic oil is blended with mineral diesel in different proportions viz. 50, 40, 30, 20 and 10 per cent by volume. The characterization of fuel samples are done by standard methods. The performance characteristics are studied by conducting test on common rail direct injection (CRDI) test rig. Experiments were carried out to assess the performance characteristics of a CRDI diesel engine working with blends of tyre pyrolytic oil (TPO) with diesel fuel (DF) consisting of 10, 20, 30, 40 and 50 per cent of tire oil. Pyrolysis is a technical solution to handle the issue of safe disposal of used tyres. From the results it can be concluded that the brake thermal efficiency of the engine working with TPO-DF blends increases with change in blend concentration and always higher than diesel fuel.

Comparison of performance and emissions of a CRDI diesel engine fuelled with biodiesel of different origin

In the present paper, laboratory produced, animal origin biofuels (swine lard and turkey lard had been used as raw material for biofuel production) were evaluated in terms of physicochemical parameters and compared with commercial mineral diesel fuel and its mixture with rapeseed oil methyl esters. Basing on the results of physicochemical parameters assessment, mixtures containing 75% share of bio-component were preselected for further engine tests. The engine tests were performed on a medium-duty, turbocharged, Common Rail, Direct Injection (CRDI) diesel engine, using factory control maps. The scope of experiments included steady state measurements for two rotational speeds (1500 and 3000 RPM), for which full load sweep had been performed. Two injection strategies were utilized: single pulse (for 3000 RPM) and multi-pulse injection (1500 RPM). The research covered evaluation of engine performance parameters and full exhaust emissions. Furthermore, detailed combustion analysis was performed.The study confirmed that high quality fuel can obtained from waste fatty material. The mixtures containing up to 75% of bio-component are suitable for modern CRDI combustion engines, though slight deterioration of engine performance parameters can be expected. An average brake specific fuel consumption increased by 13% compared to reference, for biodiesel mixtures derived from animal fatty material. At the same time a 3% increase against rapeseed oil/diesel mixture was recorded. This was correlated with a minor reduction of brake fuel conversion efficiency, but the average drop didn’t exceed 2% for all examined biodiesels.A significant reduction in exhaust gas emissions was observed, when comparing biofuel operation to reference diesel. The use of swine lard methyl ester/diesel mixture caused average reduction of hydrocarbon concentration (THC) by 13%, carbon monoxide (CO) by 22% and carbon dioxide (CO2) by 7%. The turkey biodiesel emission results were respectively: 9%, 20% and 6% reduced. NOx emission increased on average by 7% for both animal origin biofuels.

Investigation of microalgae HTL fuel effects on diesel engine performance and exhaust emissions using surrogate fuels

This paper builds on previous work using surrogate fuel to investigate advanced internal combustion engine fuels. To date, a surrogate fuel of this nature has not been used for microalgae hydrothermal liquefaction (HTL) biocrude. This research used five different chemical groups found in microalgae HTL biocrude to design a surrogate fuel. Those five chemical groups constitute around 65% (by weight) of a microalgae biocrude produced by HTL. Weight percentage of the microalgae HTL biocrude chemical compounds were used to design the surrogate fuel, which was miscible with diesel at all percentages. The engine experiments were conducted on a EURO IIIA turbocharged common-rail direct-injection six-cylinder diesel engine to test engine performance and emissions. Exhaust emissions, including particulate matter and other gaseous emissions, were measured with the surrogate fuel and a reference diesel fuel. Experimental results showed that without significantly deteriorating engine performance, lower particulate mass, particulate number and CO emissions were observed with a penalty in NOx emissions for all surrogate blends compared to those of the reference diesel.

Experimental investigation of a turbocharged CRDI diesel engine fueled with Tung oil-diesel-ethanol microemulsion fuel

Vegetable oils are being considered as a renewable energy alternative for diesel fuel. Microemulsification can be used to reduce vegetable oil viscosity without complex chemical transformation processes. In this paper, a turbocharged common rail direct injection (CRDI) diesel engine was used to investigate the properties, performance, combustion and emission characteristics of the microemulsion fuels consisting of Tung oil, diesel, ethanol and surfactant. The experimental results presented that, with the volume fraction of ethanol increase, the viscosity and density of the microemulsion fuels were decreased and approached to that of diesel fuel. The ignition delay of the microemulsion fuels was longer than that of diesel fuel, and the curves of in-cylinder pressure, pressure rise rate and heat release rate showed different trend from that of diesel fuel. The brake specific fuel consumptions (BSFC) were slightly higher for the microemulsion fuels, but the brake thermal efficiencies (BTE) were also higher than those of diesel fuel. The microemulsion fuels showed evidently lower smoke emissions, but higher nitrogen oxides (NOx) emissions at high engine loads. The hydrocarbon (HC) and carbon monoxide (CO) emissions were slightly higher at low engine loads for the microemulsion fuels.

Evaluation of ethanol and isopropanol as additives with diesel fuel in a CRDI diesel engine

In this study, alcohol fuels such as ethanol and isopropanol were used as additives with diesel fuel and two blends (15% ethanol-85% diesel fuel, and 15% isopropanol-85% diesel fuel) were prepared. Detailed and comparative performance, combustion, injection, and emission analysis of these blends and pure diesel fuel were performed in a common rail direct injection (CRDI) diesel engine. The test engine was operated under three engine speeds (1500, 2000 and 2500rpm) and four engine loads (BMEP: 3.3, 5.0, 6.6 and 8.3Bar) test conditions. According to the experimental results, alcohol fuel blends with diesel fuel caused higher brake specific fuel consumption (BSFC) values. Maximum cylinder pressure (MCP) values of the fuel blends were slightly higher than those of pure diesel fuel on average. The pilot and main injection characteristics of the CRDI fuel system showed different trends with respect to the engine load and speed. Outcomes of emission tests revealed that the CRDI diesel engine fueled with alcohol-diesel fuel blends emitted higher THC, CO and NOx emissions compared to neat diesel fuel. Alcohol fuel blends did not significantly affect CO2 emissions. Ethanol-diesel and isopropanol-diesel fuel blends had similar combustion and emission results to each other.

Experimental investigations on CRDI diesel engine fuelled with acid oil methyl ester (AOME) and its blends with ethanol

Biodiesel which is propelled as substitute to diesel fuel though attractive is not viable at present state because of its high production cost with the major concern of finding a permanent resource. As basically biodiesel is a assortment of fatty acid methyl ester it can also be produced from non-glyceride sources like acid oil which is non-edible, easily obtainable in significant amounts at the majority of the vegetable oil processing plants. This paper mainly focuses on the utilization of Acid Oil Methyl Ester (AOME) and its combinations with diesel and ethanol in different proportionsin a modified diesel engine fitted with Common Rail Direct Injection (CRDI) facilities. Acid oil was suitably trans-esterified to obtain its ester AOME and was subsequently blended with diesel and ethanol and characterization of the obtained fuels were done. A functional single cylinder diesel engine was duly converted to CRDI engine in which Conventional Mechanical Fuel Injection System (CMFIS) was replaced with CRDI facilities in order to inject biodiesel at higher injection pressures. Experiments were conducted to examine the influence of Injection Timing (IT), and Injector opening Pressure (IP) on the performance of modified CRDI engine fuelled with AOME and its blends with diesel and ethanol for improved engine performance. The experimental examination revealed IT of 10obTDC as well as IP of 900 bar as the most excellent engine operating parameters to achieve the highest Brake Thermal Efficiency (BTE) with lowered Hydro-Carbon (HC), Carbon Monoxide (CO), smoke emissions while, oxides of nitrogen (NOx) emissions were found to be superior for the fuel combinations employed in the investigation.Keywords: Diesel, Ethanol, Acid oil methyl ester (AOME), Common Rail Direct Injection (CRDI), Emissions

Effect of injection parameters on performance and emission characteristics of a CRDi diesel engine fuelled with acid oil biodiesel–ethanol blended fuels

ABSTRACTThe objective of this paper is to study the effect of injection timing and injection pressure on the engine performance and emission characteristics in a single-cylinder common rail direct injection (CRDi) diesel engine fuelled with acid oil biodiesel, diesel and ethanol blends. The biodiesel used for the study was obtained by a suitable esterification of acid oil named as acid oil methyl ester (AOME) and was subsequently blended with diesel and ethanol in varied percentage. Characterization of these fuels and their blends has been done to ascertain the applicability of these fuels for the existing engine. The feasibility of using a high percentage of biodiesel in diesel–ethanol blends has been investigated. Initially the experiments were carried out on a CRDi engine with diesel, biodiesel and their blends to optimize the injection timing (IT), where IT was varied from 25° before top dead centre (bTDC) to 5° after top dead centre (aTDC) keeping injector pressure (IP) of 600 bar, compression ratio (CR) of 17.5 and speed of 1500 rpm. Results showed that improved brake thermal efficiency (BTE) is achieved between IT of 15 to 10° bTDC. Increased ethanol content in the blend resulted in increased BTE and the blends showed higher HC and CO and reduced NOx emissions compared to diesel fuel. Finally, experiments were conducted to optimize IP where IP was varied from 600 to 1000 bar keeping optimized IT of 10° bTDC, CR of 17.5 and speed of 1500 rpm. Results revealed that maximum BTE was obtained at 900 bar. As the alcohol concentration in the blends increases, CO and HC emissions increased while NOX emissions reduced. From the experimental study, IT of 10° bTDC and IP of 900 bar were optimized for better performance with significant reduction in emissions. AOME (60%) and their blends with ethanol and diesel can be successfully used as an alternative fuel with high injection pressures in diesel engines.

Combustion and emission characteristics of diesel-tung oil-ethanol blended fuels used in a CRDI diesel engine with different injection strategies

An experimental investigation has been carried out to analyze the performance, emission and combustion characteristics of a common rail direct injection (CRDI) compression ignition (CI) engine fueled with diesel-tung oil-ethanol blended fuels with different ratio of volume fraction. Different injection strategies were adopted at different engine loads for the test engine. The viscosity, density and lower calorific value have also been measured. The experimental results indicated that, compared with diesel fuel, the ignition delay showed a little longer, the peak in-cylinder pressure and heat release rate were higher, while the combustion duration was slightly shortened for the blended fuels. The brake specific fuel consumption (BSFC) was increased, while the brake thermal efficiency (BTE) was increased with the growth of tung oil and ethanol volume fraction. Carbon monoxide (CO) emissions of the blended fuel were higher at low engine loads, and hydrocarbon (HC) emissions were higher and increased with the tung oil and ethanol addition. Nitrogen oxide (NOx) emissions of the blended fuel were lower at low engine loads and slightly higher at high engine loads. Smoke emissions were drastically reduced at high engine loads. In general, the addition of ethanol had stronger influence on the engine performance than tung oil.

Multizone Phenomenological Modeling of Combustion and Emissions for Multiple-Injection Common Rail Direct Injection Diesel Engines

Common rail direct injection (CRDI) system is a modern variant of direct injection diesel engine featuring higher fuel injection pressure and flexible injection scheduling which involves two or more pulses. Unlike a conventional diesel engine, the CRDI engine provides simultaneous reduction of oxides of nitrogen and smoke with an injection schedule that has optimized start of injection, fuel quantity in each injection pulse, and dwell periods between them. In this paper, the development of a multizone phenomenological model used for predicting combustion and emission characteristics of multiple injection in CRDI diesel engine is presented. The multizone spray configuration with their temperature and composition histories predicted on phenomenological spray growth and mixing considerations helps accurate prediction of engine combustion and emission (nitric oxide and soot) characteristics. The model predictions of combustion and emissions for multiple injection are validated with measured values over a wide range of speed and load conditions. The multizone and the two-zone model are compared and the reasons for better comparisons for the multizone model with experimental data are also explored.

Cold start particle number, size and mass emissions from a CRDI diesel engine running on biodiesel blends in a cold environment

ABSTRACTBiodiesel is a renewable alternative fuel, used as a blending component for diesel, which reduces hydrocarbon and particulate matter emissions with marginal increases in nitrogen oxide emissions. Engine performance varies with ambient temperature conditions, engine design, fuel, lubricant and operating conditions. This research investigated the impact of biodiesel blends on a common rail direct injection (CRDI) diesel engine performance and exhaust emission characteristics during cold start at different ambient temperature conditions. Biodiesel blends improved the combustion and thereby reduced the sudden rise in peak speed and the gaseous emissions at normal ambient temperature. At cold ambient conditions biodiesel severely affected the cold start performance and increased the gaseous emissions. During cold start, the biodiesel blends emitted a larger number of particles of diameter 100–1000 nm at cold ambient temperature compared to normal ambient temperature. The particulate surface area and mass was increased by 2–3 times and 3–6 times, respectively, for the biodiesel blends with the drop in ambient temperature. The higher number of larger diameter particles increased the particulate mass significantly at cold ambient temperature conditions.

Effects of nano metal oxide blended Mahua biodiesel on CRDI diesel engine

In this paper, aluminium oxide nanoparticles (ANPs) were added to Mahua biodiesel blend (MME20) in different proportions to investigate the effects on a four stroke, single cylinder, common rail direct injection (CRDI) diesel engine. The ANPs were doped in different proportions with the Mahua biodiesel blend (MME20) using an ultrasonicator and a homogenizer with cetyl trimethyl ammonium bromide (CTAB) as the cationic surfactant. The experiments were conducted in a CRDI diesel engine at a constant speed of 1500 rpm using different ANP-blended biodiesel fuel (MME20 + ANP50 and MME20 + ANP100) and the results were compared with those of neat diesel and Mahua biodiesel blend (MME20). The experimental results exposed a substantial enhancement in the brake thermal efficiency and a marginal reduction in the harmful pollutants (such as CO, HC and smoke) for the nanoparticles blended biodiesel.

Performance and emissions of a CRDI diesel engine fuelled with swine lard methyl esters–diesel mixture

Biodiesel, as a product of the transesterification reaction of fatty material, is gaining appreciation all over the world and confirms its beneficial effect on the reduction of exhaust gases when (even partly) used to power compression-ignition engines. Although many researchers have focused on biofuel production and its application in combustion engines, continuous development of injection systems, providing new control strategies, encourages the seeking for new ways of optimizing biofuel combustion. In particular, very little attention has been given to the possibility of using biofuels in modern CRDI (Common Rail Direct Injection) engines with divided injection technology. There is also limited information available on engines operating on biodiesel of animal origin and their performance and emissions for such fuels.Because of this gap of knowledge, in the present study, the authors focused on analysing the phenomena of combustion of animal-origin biodiesel mixtures in a CRDI engine. Swine lard methyl esters, obtained in the laboratory by a single-step alkali transesterification process as a biocomponent, and mineral diesel were used to obtain B25, B50, B75 mixtures (25%, 50% and 75% of biocomponent concentration by volume). The physicochemical parameters of B25, B50, B75, pure esters and mineral diesel were examined to determine whether the fuels met quality standards. The mixtures were used to fuel a 2.6L Andoria CRDI engine placed on a dynamometer test stand. Tests were carried out in steady state operation, at rotational speeds when two different injection strategies occur (single injection and two subsequent injections), also different load conditions were introduced during tests. During the tests, engine performance and exhaust gas emissions were measured and analysed in detail.The study has confirmed the capability of using diesel–biodiesel mixtures containing up to 75% biocomponents in a modern CRDI engine without any operational issues. A minor deterioration of fuel performance parameters with an increasing biodiesel share has been observed. Brake-specific fuel consumption increased on average by 3.2%, 8.5% and 13.8% for B25, B50 and B75, respectively. An average reduction of brake fuel conversion efficiency was observed, amounting to 1.6%, 4.8% and 7.8% for B25, B50 and B75, respectively. Significant reduction of exhaust gas emissions (excluding NOx) and opacity was also observed in all examined operation conditions. Total hydrocarbon concentration was reduced by a maximum of 72% for the B75 mixture for a speed of 1500RPM and 100Nm load. The best emission performance was observed for operation conditions when a short pre-injection occurred early in the compression phase, before the main fuel injection. This has proven that advanced injection strategies can be applied to fuel mixtures with high biodiesel share, especially for low engine load conditions.