Common Rail Direct Injection Diesel Research Articles

Combustion and performance evaluation of a common rail DI diesel engine fueled with ethyl and methyl esters

Biodiesel is a renewable fuel for diesel engines and it can be produced from different feedstocks via different types of alcohols and catalysts. Alcohol type directly affects the fuel properties of the produced biodiesel. The difference in the fuel properties may cause different performance, combustion and injection characteristics in diesel engines. In the present study, a common rail direct injection (CRDI) diesel engine was operated with waste vegetable frying oil based ethyl and methyl esters. The engine was operated under the conditions of three different engine speeds (1500, 2000 and 2500 rpm) and four engine loads (BMEP: ∼ 3.3, 5.0, 6.6 and 8.3 bar). According to the results of comprehensive combustion and performance tests, ethyl and methyl esters showed higher brake specific fuel consumption, higher peak heat release rate and cylinder pressure values compared to pure diesel fuel on average. Ethyl and methyl esters showed similar performance and combustion characteristics. Pilot injection and main injection durations of the ester fuels were higher than those of diesel fuel. The relationship between the determined and the calculated combustion and injection values of the test fuels changed with respect to engine operating parameters.

Combustion characteristics of a common rail direct injection engine using different fuel injection strategies

Fuel injection parameters such as fuel injection pressure (FIP) and start of injection (SOI) timing significantly affect combustion, performance, emission and durability of a common rail direct injection (CRDI) diesel engine. In this study, a state-of-the-art single cylinder research engine was used to investigate the effects of FIP and SOI timings on engine combustion characteristics, which affects heat transfer and soot formation as well. The experimental setup consisted of an instrumented single cylinder engine with provision to vary the fuel injection parameters along with online high speed combustion data acquisition and analysis system. Experiments were conducted at constant engine speed (1500 rpm) at four different FIPs (300, 500, 750 and 1000 bar), four different SOI timings and different fuel injection quantities. Combustion characteristics of the engine were analyzed using exhaustive heat release analysis based on in-cylinder pressure data. In direct injection compression ignition (DICI) engines, fuel vaporization and heat transfer characteristics affect fuel-air mixing, which is also influenced by the FIP and SOI timings. These injection parameters significantly control the rate of pressure rise (ROPR), and heat release rate (HRR), which in-turn affect the heat transfer from the engine cylinder as well as the engine power output. Therefore, it is necessary to optimize the fuel injection parameters to develop efficient and clean combustion diesel engines.

A novel study on the effect lemon peel oil as a fuel in CRDI engine at various injection strategies

Lemon peel oil is one of the renewable and biodegradable biofuel for diesel engine applications due to its low viscous nature. This study aims to observe the performance and emission characteristics of a common rail direct injection diesel engine at various fuel injection strategies under different loading conditions. An open type electronic control unit is used to control the fuel injection timing, injection rate and split injection at various injection pressures. In this research work, 20% lemon peel oil-diesel blend (by volume) is injected at a pressure of 400 bar, 500 bar and 600 bar with 10% pilot injection by volume and the results are compared with diesel fuel at same injection conditions. Further, pilot injection quantity of lemon peel oil blend is varied by 20% and 30% of total volume of fuel injected at 600 bar injection pressure. Finally, the experimental work is carried out in common rail direct injection diesel engine fuelled with lemon peel oil blend under 10% cooled exhaust gas recirculation condition. The study reveals that the brake thermal efficiency is improved with increase in injection pressures and pilot injection rates. However, this trend has been changed during 10% EGR addition for lemon peel oil blend operation at 30% pilot injection rate. The combustion characteristics are improved for lemon peel oil blend for 600 bar injection pressure with 20% and 30% pilot injection rates compared to 10% pilot injection rate. The higher pilot injection rate has shown significant reductions in carbon monoxide, hydrocarbon and smoke emissions. However, the emission results are reversed with 10% exhaust gas recirculation at 600 bar injection pressure of lemon peel oil blend. There is a significant reduction in NOx emission for low injection pressure of lemon peel oil blend at 10% pilot injection rate.

Evaluation of Fuel Injection Strategies for Biodiesel-Fueled CRDI Engine Development and Particulate Studies

Fuel injection parameters such as fuel injection pressure (FIP) and start of main injection (SoMI) timings significantly affect the performance and emission characteristics of a common rail direct injection (CRDI) diesel engine. In this study, a state-of-the-art single cylinder research engine was used to investigate the effects of fuel injection parameters on combustion, performance, emission characteristics, and particulates and their morphology. The experiments were carried out at three FIPs (400, 700, and 1000 bar) and four SoMI timings (4 deg, 6 deg, 8 deg, and 10 deg bTDC) for biodiesel blends [B20 (20% v/v biodiesel and 80% v/v diesel) and B40 (40% v/v biodiesel and 60% v/v diesel)] compared to baseline mineral diesel. The experiments were performed at a constant engine speed (1500 rpm), without pilot injection and exhaust gas recirculation (EGR). The experimental results showed that FIP and SoMI timings affected the in-cylinder pressure and the heat release rate (HRR), significantly. At higher FIPs, the biodiesel blends resulted in slightly higher rate of pressure rise (RoPR) and combustion noise compared to baseline mineral diesel. All the test fuels showed relatively shorter combustion duration at higher FIPs and advanced SoMI timings. The biodiesel blends showed slightly higher NOx and smoke opacity compared to baseline mineral diesel. Lower particulate number concentration at higher FIPs was observed for all the test fuels. However, biodiesel blends showed emission of relatively higher number of particulates compared to baseline mineral diesel. Significantly lower trace metals in the particulates emitted from biodiesel blend fueled engine was an important finding of this study. The particulate morphology showed relatively smaller number of primary particles in particulate clusters from biodiesel exhaust, which resulted in relatively lower toxicity, rendering biodiesel to be more environmentally benign.

Experimental optimization of reactivity controlled compression ignition combustion in a light duty diesel engine

Reactivity Controlled Compression Ignition (RCCI) is emerging as a most promising combustion strategy to achieve near zero oxides of nitrogen (NOx) and smoke emissions along with higher brake thermal efficiency. The present work attempts to implement RCCI strategy in a production, light duty diesel engine by replacing an existing mechanical fuel injection with a flexible common rail direct injection diesel system and a low pressure gasoline port fuel injection system. Further, the engine compression ratio is reduced through modifications in piston bowl. Using a suitable controller, the engine operating parameters in terms of direct injected diesel timings, injection pressure, port injected gasoline quantity and gasoline to diesel ratio at each load conditions are optimized to achieve maximum brake thermal efficiency. Before modifications, the engine is run under conventional combustion mode at rated speed, varying loads to establish baseline reference data. The obtained results show that the engine could be operated in RCCI mode over its entire load range with a maximum increase of 14.2% brake thermal efficiency, near zero NOx and smoke emissions compared to conventional combustion. Further, reducing compression ratio is found to increase brake thermal efficiency by 7.6% and reduce carbon monoxide by 16.8% in RCCI.

An experimental investigation on the usage of waste frying oil-diesel fuel blends with low viscosity in a Common Rail DI-diesel engine

In this study, waste frying oil (WFO) was blended with mineral diesel fuel (MDF) (without converting biodiesel) in the ratios of 2%, 7%, 15% and 25% (v/v) on the condition that the viscosities of all WFO-MDF blends were lower than viscosity upper limit given in European Biodiesel Standard, EN 14214. It was aimed to determine the influences of the direct usage of WFO-MDF blends with low viscosity on the performance, injection, combustion, and emission characteristics of a Common Rail Direct Injection (DI) diesel engine. Engine tests were performed at constant engine speed of 2000 rpm and five different engine loads (50 Nm, 75 Nm, 100 Nm, 125 Nm and 150 Nm). WFO blends’ brake specific fuel consumption values were higher than those of MDF. The brake thermal efficiencies of MDF are better than WFO-MDF blends. Slightly higher cylinder gas pressures were attained with the neat MDF but the crank angles where the peak pressures obtained were close to each other. Injection timings did not show significant differences, but fuel quantities injected during pilot and main injection were higher for WFO blends. Excluding 50 Nm engine load, ignition delay and combustion durations were consistent with each other. Compared to MDF as the reference fuel, the use of WFO caused to increase in all exhaust emission types measured, especially THC emissions. The deterioration in performance and emission characteristics increased with increasing engine load and WFO content of the fuel blend.

Effects of triglyceride gasoline blends on combustion and emissions in a common rail direct injection diesel engine

This study presents the combustion and emission results using a blend of unrefined triglycerides (straight vegetable oils) and regular unleaded gasoline in a compression ignition engine typically used in farming machinery. Most farm equipment is powered by diesel engines. A sizable cost of producing a crop on a farm can be attributed to fuel—diesel in such cases. Farmers and researchers have been interested in the use of alternative fuels, especially triglycerides, which could potentially bring down the fuel cost portion of the farm input costs. One of the major drawbacks of using unrefined triglycerides is poor cold flow properties due to high density and viscosity. To overcome this, the triglycerides can be blended with gasoline to lower the density and viscosity. This blend has been used in existing diesel engines without the need for any modification to the engine or its control system. The experiments were conducted on a 4.5-L Tier 3 engine. The fuel used was a blend of unrefined canola triglyceride and regular unleaded gasoline (10% by volume). Measurements include mass fraction burned combustion pressure, fuel consumption and pollutant emissions. The fuel consumption of TGB10 was lower than most straight vegetable oils found in the literature, but higher than diesel. The peak pressure of TGB10 was slightly higher than diesel and occurred earlier than diesel. The brake-specific NOx was lower than diesel at lower and no load points. Particulate matter emissions of TGB10 were higher than diesel at rated speed. Total hydrocarbon emissions were generally higher than diesel. CO emissions were lower than diesel except at low or no load points where they were significantly higher.

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.

Performance, emission and combustion characteristics of a multicylinder common rail direct injection diesel engine fuelled with ethanol-acid oil methyl ester-diesel blends

ABSTRACTIn the present work biodiesel was used as an emulsifier for diesel and ethanol mixtures and used for diesel engine applications. The biodiesel was produced from acid oil, a waste by-product of vegetable oil refineries. The fatty acid methyl ester mixture, called acid oil methyl ester (AOME), was blended with diesel and ethanol. Characterization of these ethanol-biodiesel-diesel (EBD) blends was done to ascertain their suitability for common rail direct injection (CRDI) engines. The objective of the present work is to determine the optimal use of EBD blends. The selected blends were tested in a four-cylinder CRDI engine for different loads and at engine speeds of 1200, 1500 and 1800 rpm. Performance, emission and combustion characteristics of these blends ware then compared with standard diesel fuel. The studies indicate decreased brake thermal efficiency and increased carbon monoxide, hydrocarbon and smoke emissions as alcohol concentration in the blends increased while NOx emissions were significantly reduced. As engine speeds increased from 1200 to 1800 rpm, brake thermal efficiency increased, carbon monoxide, hydrocarbon and smoke emissions were reduced and NOx emissions increased significantly. Knocking was observed for engine speeds beyond 1800 rpm.

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.

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.

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.

Influence of narrow fuel spray angle and split injection strategies on combustion efficiency and engine performance in a common rail direct injection diesel engine

Direct injection diesel engines have been widely used in transportation and stationary power systems because of their inherent high thermal efficiency. On the other hand, emission regulations such as NOx and particulates have become more stringent from the standpoint of preserving the environment in recent years. In this study, previous results of multiple injection strategies have been further investigated to analyze the effects of narrow fuel spray angle on optimum multiple injection schemes in a heavy duty common rail direct injection diesel engine. An advanced computational fluid dynamics simulation has been carried out on a Caterpillar 3401 diesel engine for a conventional part load condition in 1600 r/min at two exhaust gas recirculation rates. A good agreement of calculated and measured in-cylinder pressure, heat release rate and pollutant formation trends was obtained under various operating points. Three different included spray angles have been studied in comparison with the traditional spray injection angle. The results show that spray targeting is very effective for controlling the in-cylinder mixture distributions especially when it accompanied with various injection strategies. It was found that the optimum engine performance for simultaneous reduction of soot and NOx emissions was achieved with 105° included spray angle along with an optimized split injection strategy. The results show, in this case, the fuel spray impinges at the edge of the piston bowl and a counterclockwise flow motion is generated that pushes mixture toward the center of the piston bowl.

The installation of a common rail diesel engine on a light helicopter of the eurocopter EC120 class

<p>A feasibility study for the installation of a CRDID (Common Rail Direct Injection Diesel) on a light helicopter is introduced. The total mass available for the CRDID is evaluated starting from fuel consumption and helicopter data. The conversion of an automotive unit was discarded to excessive mass and excessive costs of the conversion. A derivative of an automotive engine was then considered. This solution proved to be feasible. The installation of the new CRDID was then studied. The turbocharger and the cooling system were defined for the application. The result was the evaluation of the power plant installation mass that proved to be much lower than the maximum admissible. The installation is then possible.</p>

직접분사식 압축착화 디젤엔진의 분사시기 변화에 따른 연소 및 성능특성에 관한 연구

Since the oil shock of 1970's there was a strong upward tendency for the use of the high viscosity and poorer quality fuels. Therefore the misfiring engine occurs due to the decrease of quantity injected for lean burn and emission control in Compression Ignition Common Rail Direct Injection diesel engine. In this study, it is designed and used the test bed which is installed with fuel injector controller. In addition to equipped engine using CRDI by controlling the injection timing with mapping modulator, it has tested and analyzed the engine performance and combustion characteristics, as it is varied that they are the operating parameters: fuel injected quantity, engine speed and injection timing.

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.

Zero-Dimensional Analysis of Combustion in a Multiple-Injection CRDI Engine Using Wiebe Law

Common rail direct injection system (CRDI) offers the potential to achieve optimal combustion and emission characteristics. An empirical analysis of engine combustion process incorporating Wiebe type burn rate law approach is useful not only in understanding the combustion characteristics of a CRDI engine but also aids in diagnosis and control of the combustion process wherever required from the performance and emission standpoint. This paper presents a methodology for applying the burn rate law for common rail direct injection diesel engines adopted with split injection by using Wiebe’s correlation. The analysis reveals that while the empirical constant ‘m’ (shape factor) for both pilot and main injections is independent of engine load and seems to be affected by engine speed only, the constant ‘a’ (efficiency parameter) seems to be influenced by the engine speed, load and injection conditions. A correlation for these empirical constants with the respective parameters of dependence can be formulated which can be used to analyze the effect of change in engine operating conditions on combustion characteristics without conducting engine experiments.

Individual hydrocarbons and particulate matter emission from a turbocharged CRDI diesel engine fueled with n -butanol/diesel blends

The objectives of this study are to investigate the effect of a diesel fuel blend with n-butanol on the individual hydrocarbons and particulate matter (PM) of a turbocharged common rail direct injection diesel engine and to compare the results with the neat diesel fuel operation case. The emission characteristics were estimated by using 5%, 10%, and 20% (by volume) of n-butanol blended with conventional diesel fuel. The measured emissions were the regulated emissions of total hydrocarbons (HC) or individual HC, CO, NOx, PM and the non-regulated emission of formaldehyde, which were measured under three different engine loads (25.4, 52.9 and 78.4 N m) and three different engine speeds (1500, 2000 and 2500 rpm). It was found that more ethylene and benzene are emitted under low load condition, and that their amounts increase with increasing n-butanol blend ratio. The fuels blended with over 10% butanol produced higher non-regulated formaldehyde (HCHO) emission than the neat diesel fuel under lower engine load conditions. The particle numbers for particles smaller than 50 nm were higher for the fuel blended with 20% butanol in diesel fuel compared to the neat diesel fuel. From the TEM images, it was found that a larger number of individual particles with a size of 10–30 nm were stacked on top of each other in a circular pattern.