Rail Direct Injection Diesel Engine Research Articles

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.

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.

Influence of Engine Speed on Mixing and Emission Characteristics of Multiple-Injection Common Rail Direct Injection Diesel Engine

Increase in engine speed increases the in-cylinder turbulence and hence the rate of mixing. However, it is difficult to directly measure the mixing rate and relating its effect on emissions. Hence, in this paper, the comparison of mixing rate at different engine speeds are demonstrated with a multi-zone phenomenological model which has been developed and validated on a wide range of engine operating conditions. The mixing rate is evaluated using a standard quasi-dimensional k-ε formulation. The quantitative predictions of mixing rates at different engine speed substantiate the cause of soot emission reduction at higher engine speed.

Robust Indicated Mean Effective Pressure and Combustion Lambda Feedback Control for Lean NOx Trap Regeneration in a 2.2 L Common Rail Direct Injection Diesel Engine

To meet stringent Euro-6 emission regulations, a lean NOx trap (LNT) catalyst should be considered to effectively abate NOx emissions. This LNT catalyst should be periodically regenerated without deteriorating driving quality and also satisfy emission constraints, such as CO, low particulate matter or smoke, and low O2 during the regeneration phase. As a means of reductant delivery, in-cylinder post fuel injection with a feedforward (FF) control has been applied due to its simple implementation in an engine management system (EMS). However, with this method, it is difficult to satisfy the driving quality and emission constraints during the transition to or out of the regeneration phase. To solve this problem, we propose a novel LNT regeneration control method using an indicated mean effective pressure (IMEP) and a combustion lambda feedback (FB) control combined with the FF control. For the precise FB control of the post injection timing, among the location of the second rate of heat release (ROHR) peak, the magnitude of the second ROHR peak, and IMEP, the IMEP was selected as a control parameter because of its lowest cyclic variation. In addition, the exhaust lambda control was applied for the accurate FB control of the post injection quantity. The proposed method was implemented in an in-house EMS. The performance in several engine tests indicated that the torque fluctuation was minimized and all emission constraints were effectively satisfied. Furthermore, this method was also robust with regard to the thermal disturbance.

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.

Fuel characterisation, engine performance, combustion and exhaust emissions with a new renewable Licella biofuel

The current study investigates the opportunity of using Licella biofuel as a partly renewable fuel provided by Licella P/L. Hereafter this fuel will be referred to as Licella biofuel. The renewable component of the Licella biofuel was made from the hydrothermal conversion of Australian pinus radiata wood flour using Licella’s proprietary Cat-HTR™ technology. The diesel-soluble component of the hydrothermal product was extracted into road diesel to give a blended fuel containing approximately 30% renewable material with the balance from diesel. This was further blended with a regular diesel fuel (designated R0) to give fuels for testing containing 5%, 10% and 20% renewable fuel (designated R5, R10 and R20). Some of the key fuel properties were measured for R30 and compared with those of regular diesel fuel. The engine experiment was conducted on a four-cylinder turbocharged common rail direct injection diesel engine. All experiments were performed with a constant speed and five different engine loads. Exhaust emissions including particulate matter (PM) mass and numbers, nitric oxide (NO), total unburnt hydrocarbon (THC), carbon dioxide (CO2) and performance parameters including brake power (BP), indicated power (IP), brake mean effective pressure (BMEP), indicated mean effective pressure (IMEP), mechanical efficiency (ME), brake thermal efficiency (BTE) and brake specific energy consumption (BSEC) were investigated for all four blends (R0, R5, R10 and R20). Among other engine parameters, in-cylinder pressure, heat release rate (HRR) and pressure (P) versus volume (V) diagrams were also investigated for the four fuel blends.

Effect of diesel fuel blend with n-butanol on the emission of a turbocharged common rail direct injection diesel engine

Abstract The objectives of this study are to investigate the effect of diesel fuel blend with n-butanol on the emission of turbocharged common rail direct injection (CRDI) diesel engine and to compare the results with the neat diesel fuel operation case. The blends considered here were blends of diesel fuels with 10% and 20% (by volume) n-butanol. Engine performance and emission characteristics were measured by the European Stationary Cycle (ESC) test. Emissions of HCs, CO, NOx, HCHO, HCOOH and NH 3 were measured by Fourier Transform Infrared Spectroscopy (FTIR). Size and number distribution of particulate matter (PM) were measured by the Scanning Mobility Particle Sizer (SMPS). From the results, for the n-butanol blend, NOx emission increased compared with the neat diesel fuel case. At the case of 20% butanol, both THC and CO emissions increased significantly, and both HCHO and HCOOH increased modestly under the low loading of ESC 7, 9 and 11 mode compared with the neat diesel fuel case. Higher blending ratio (>20%) of butanol fuels could contribute to the precursor of PAHs formation such as toluene and benzene in diesel combustion. BU5 blend could be a better option to reduce the PM mass and the emissions of nanosized PM under 50 nm.

Effects of Canola Oil Biodiesel Fuel Blends on Combustion, Performance, and Emissions Reduction in a Common Rail Diesel Engine

In this study, we investigated the effects of canola oil biodiesel (BD) to improve combustion and exhaust emissions in a common rail direct injection (DI) diesel engine using BD fuel blended with diesel. Experiments were conducted with BD blend amounts of 10%, 20%, and 30% on a volume basis under various engine speeds. As the BD blend ratio increased, the combustion pressure and indicated mean effective pressure (IMEP) decreased slightly at the low engine speed of 1500 rpm, while they increased at the middle engine speed of 2500 rpm. The brake specific fuel consumption (BSFC) increased at all engine speeds while the carbon monoxide (CO) and particulate matter (PM) emissions were considerably reduced. On the other hand, the nitrogen oxide (NOx) emissions only increased slightly. When increasing the BD blend ratio at an engine speed of 2000 rpm with exhaust gas recirculation (EGR) rates of 0%, 10%, 20%, and 30%, the combustion pressure and IMEP tended to decrease. The CO and PM emissions decreased in proportion to the BD blend ratio. Also, the NOx emissions decreased considerably as the EGR rate increased whereas the BD blend ratio only slightly influenced the NOx emissions.

Combustion analysis of microalgae methyl ester in a common rail direct injection diesel engine

In this study, the biodiesel properties and effects of blends of oil methyl ester petroleum diesel on a CI direct injection diesel engine is investigated. Blends were obtained from the marine dinoflagellate Crypthecodinium cohnii and waste cooking oil. The experiment was conducted using a four-cylinder, turbo-charged common rail direct injection diesel engine at four loads (25%, 50%, 75% and 100%). Three blends (10%, 20% and 50%) of microalgae oil methyl ester and a 20% blend of waste cooking oil methyl ester were compared to petroleum diesel. To establish suitability of the fuels for a CI engine, the effects of the three microalgae fuel blends at different engine loads were assessed by measuring engine performance, i.e. mean effective pressure (IMEP), brake mean effective pressure (BMEP), in cylinder pressure, maximum pressure rise rate, brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), heat release rate and gaseous emissions (NO, NOx, and unburned hydrocarbons (UHC)). Results were then compared to engine performance characteristics for operation with a 20% waste cooking oil/petroleum diesel blend and petroleum diesel. In addition, physical and chemical properties of the fuels were measured. Use of microalgae methyl ester reduced the instantaneous cylinder pressure and engine output torque, when compared to that of petroleum diesel, by a maximum of 4.5% at 50% blend at full throttle. The lower calorific value of the microalgae oil methyl ester blends increased the BSFC, which ultimately reduced the BTE by up to 4% at higher loads. Minor reductions of IMEP and BMEP were recorded for both the microalgae and the waste cooking oil methyl ester blends at low loads, with a maximum of 7% reduction at 75% load compared to petroleum diesel. Furthermore, compared to petroleum diesel, gaseous emissions of NO and NOx, increased for operations with biodiesel blends. At full load, NO and NOx emissions increased by 22% when 50% microalgae blends were used. Petroleum diesel and a 20% blend of waste cooking oil methyl ester had emissions of UHC that were similar, but those of microalgae oil methyl ester/petroleum diesel blends were reduced by at least 50% for all blends and engine conditions. The tested microalgae methyl esters contain some long-chain, polyunsaturated fatty acid methyl esters (FAMEs) (C22:5 and C22:6) not commonly found in terrestrial-crop-derived biodiesels yet all fuel properties were satisfied or were very close to the ASTM 6751-12 and EN14214 standards. Therefore, C.cohnii- derived microalgae biodiesel/petroleum blends of up to 50% are projected to meet all fuel property standards and, engine performance and emission results from this study clearly show its suitability for regular use in diesel engines.

The effects of early inlet valve closing and cylinder disablement on fuel economy and emissions of a direct injection diesel engine

The influence of EIVC (early inlet valve closure) on emissions, fuel economy and exhaust gas temperature of a turbocharged, 4 cylinder common rail direct injection diesel engine has been investigated and compared with the influence of deactivating two cylinders. IVC (inlet valve closing) timings were set at up to 60 CA (crank angle) degrees earlier than the production setting of 37° ABDC for the engine. At the earliest timing, effective compression ratio was reduced from 15.2:1 to 13.7:1. The effects on emissions were significant only for EIVC settings at least 40 CA degrees earlier than the production setting, and were sensitive to engine load. At 2 bar BMEP (brake mean effective pressure) and fixed levels of NOx, soot emissions were reduced but CO (carbon monoxide) and HC (hydrocarbon) increased unless fuel rail pressure was reduced. With increasing load, soot reduction diminished and was negligible at 6 bar BMEP; CO and HC emissions deteriorated further. At all conditions, EIVC raised exhaust gas temperature by >50 °C; the effect on fuel economy was negligible or a fuel economy penalty. Comparisons indicate cylinder deactivation is the more effective strategy for reducing engine-out emissions of HC and CO and raising exhaust gas temperature under light load operating conditions.

Effect of fuel injection pressure and injection timing on spray characteristics and particulate size–number distribution in a biodiesel fuelled common rail direct injection diesel engine

In this paper, effect of varying fuel injection pressures and injection timings on particulate size number distribution and spray characteristics was investigated in a single cylinder, common rail direct injection (CRDI) compression ignition (CI) engine fueled with Karanja biodiesel blends vis-à-vis baseline mineral diesel. The investigation results of spray tip penetration and spray area of biodiesel blends and diesel showed that higher fuel injection pressure result in a longer spray tip penetration and larger spray area than that at lower injection pressures at same elapsed time after the start of injection (SOI). In order to compare the effect of fuel injection parameters, 10, 20 and 50% Karanja biodiesel blends at 1500rpm engine speed were compared with baseline data from mineral diesel. It was observed that average particulate size increased with retarding the SOI timings. Particulate number concentration was lowest for 10% biodiesel blend, which increased with further increase in biodiesel content in the blended test fuel. Addition of even very small quantity of biodiesel in the test fuel helped in reducing particulate emissions.

Effects of pilot injection timing and EGR on a modern V6 common rail direct injection diesel engine

Nitric oxide and smoke emissions in diesel engine can be controlled by optimising the air/fuel mixture. Early injection produces premixed charge resulted in simultaneous NOx and smoke emissions reduction. However, there could be an increase in hydrocarbons and CO emissions due to fuel impinged to the cylinder wall. The focus of the present work is to investigate the effects of a variation of pilot injection timing with EGR to NOx and smoke level on a modern V6 common rail direct injection. This study is carried out at two different engine load conditions of 30 Nm and 55 Nm, at constant engine speed of 2000 rpm. The results show that the early pilot injection timing contributed to the lower smoke level and higher NOx emissions. The higher level of NOx is due to higher combustion temperatures resulting from the complete combustion. Meanwhile, the lower smoke level is due to complete fuel combustion and soot oxidation. The early pilot injection timing produces an intermediate main ignition delay which also contributed to complete combustion. The formation of smoke is higher at a high engine load compared with low engine load due to the higher amount of fuel being injected.

The effects of synthetically designed diesel fuel properties – cetane number, aromatic content, distillation temperature, on low-temperature diesel combustion

This study investigated the effects of synthetically designed diesel fuel properties i.e. cetane number (CN), aromatic content, and 90% distillation temperature (T90) on the combustion characteristics and exhaust emissions in low-temperature diesel combustion (LTC). LTC was achieved by a similar approach to previous work via alteration of injection strategy, a cooled heavy EGR rate at low speed and low load, and at 1500rpm and 2.6bar BMEP in a 1.9L common rail direct injection diesel engine. The test fuels were synthetically designed, whose properties constitute CNs of 30 and 55, aromatic contents of 20% and 45%, and T90 temperatures of 270 and 340°C. In LTC operating conditions, the CN is found to be the most dominant factor in the ignition delay time, followed by the T90 temperature for the lower CN fuels, and the aromatic content for the higher CN fuels. Given a CN, the location of mass fraction burned (MFB) 5% and MFB50% showed a linear relationship, and thus the aromatic content and T90 temperature effects can be diminished by adjusting the start of injection timing. PM was strongly dependent on the ignition delay time regardless of fuel types: no PM was observed as long as the ignition delay time was longer than 18°CA. For CN55 fuels, the NOx emission showed strong dependence on the location of MFB50% regardless of fuel types, i.e. NOx decreases as the MFB50% location retards. For CN30 fuels, the aromatic content acts as a crucial factor in the increase of NOx as similar to the studies of conventional diesel combustion.

Characteristics of Soot and Particle Size Distribution in the Exhaust of a Common Rail Light-Duty Diesel Engine Fuelled with Biodiesel

The effect of biodiesel blends (derived from waste oil) on soot and particle size distribution (PSD) was investigated in a light-duty common rail direct injection diesel engine under different load conditions. The experiments included four fuels: baseline diesel (D), B40, B60, and B100. (BXX means a blend of XX vol % biodiesel in diesel). Particle size distribution in exhaust was measured by a scanning mobility particle sizer (TSI SMPS3936) through a partial dilution tunnel. The results showed that as the blend ratio increased, the filter smoke number (FSN) of biodiesel blends decreased significantly. With respect to PSD at the downstream of two diesel oxidation catalysts, an increase of engine loads led to nanoparticle formation in the nucleation mode (NM) and log-modal PSD of diesel and biodiesel blends shifts to bimodal. Biodiesel blends will significantly reduce the particle number of accumulation mode (CM) due to soot oxidation from oxygen content. However, the absence of NM was still found for B100....

디젤 연소 전략에 따른 배기가스 및 탄화수소 종 분석

1.7L 커먼레일 직접분사 디젤 엔진을 이용하여 1500rpm 3.9bar BMEP 조건에서 세가지 연소 전략에 따른 배기가스 배출 특성 및 탄화수소 종 분석을 수행하였다. 첫째 전략은 EGR 을 사용하지 않고 연료 분할 분사를 이용하는 방법(split injection), 둘째는 적절한 EGR 적용 및 단일 연료분사 방법(single-1)이며 셋째는 다량의 EGR 및 레일 압력 증대 등을 통한 저온디젤연소(single-2)이다. 본 실험 조건으로부터 split injection 방법과 single-1 방법은 PM-NOx 상반 관계를 보였고, single-2 방법은 PM-NOx 상관관계에서 벗어나 PM 및 NOx 동시 저감이 가능하였다. 탄화수소 종 분석 결과, THC 배출 경향과 동일하게 탄소번호에 관계없이 split injection 이 가장 적은 배출을 보였고, single-1 그리고 single-2 의 순서로 많이 배출하였다. 메탄, 아세틸렌 및 CO 의 THC 에 대한 비율은 공연비가 농후해 짐에 따라서 증가하였고 이는 공연비가 농후에 따른 연소 영역에서 산소 농도 감소로 열해리가 증가하였기 때문이다.