Common Rail Diesel Engine Research Articles

Effects of iron-based fuel borne catalyst addition on combustion, in-cylinder soot distribution and exhaust emission characteristics in a common-rail diesel engine

• Adding Fe-FBC to diesel shortens ignition delay and accelerates combustion rate. • Fe-FBC addition decreases in-cylinder soot concentration and area occupation ratio. • Fe-FBC addition can effectively reduce gas emissions including aldehydes and PAHs. • Oxidation characteristic temperature and activation energy of soot particle decrease. • Fe-FBC addition decreases the type and content of PAHs in the SOF from the particles. In order to reduce soot emission and assist diesel particulate filter regeneration, iron-based fuel borne catalyst (Fe-FBC) was added into diesel fuel with Fe element mass fractions of 0, 200 and 400 mg/kg in the preparation of FBC fuels (marked as Diesel, Fe200 and Fe400). The in-cylinder soot distribution, pollutant emissions and particle physicochemical properties of FBC fuels were investigated on a visualization modified common-rail engine. The results show that the combustion starting point is advanced with Fe-FBC addition, while the maximum combustion pressure and heat release rate increase. The addition of Fe-FBC in diesel fuel will shorten ignition delay period, accelerate combustion process and lead to the increase of in-cylinder flame temperature, while the in-cylinder soot concentration and soot area occupation ratio are reduced significantly. HC, CO and soot emissions along with the unconventional emissions such as HCHO, CH 3 CHO and polycyclic aromatic hydrocarbons (PAHs) decrease at each load as the increase of Fe-FBC addition ratio. Compared with Diesel, the peak soot area occupation ratio and soot emissions of Fe400 decrease by 41.6% and 20.4% respectively at full load. It is also found that Fe-FBC addition decreases particle box-counting dimension, which indicates that the polymerization degree between the particles becomes weaker and their arrangement becomes more sparse and loose, so the oxidation characteristic temperature and the activation energy of soot particles decrease significantly. Fe-FBC addition can effectively reduce the type and content of PAHs and the high carbon atom number compounds in soluble organic fraction from exhaust particles.

A comparative study of combustion and emission characteristics of dual-fuel engine fueled with diesel/methanol and diesel–polyoxymethylene dimethyl ether blend/methanol

Abstract In this study, a comparative study of the combustion characteristics and performances of a dual-fuel engine fueled with diesel/methanol and diesel–polyoxymethylene dimethyl ether blend/methanol was conducted. All the experiments were conducted on a heavy-duty common rail diesel engine at an engine speed of 1800 r/min. The engine loads were fixed at low, medium, and heavy loads, with the brake mean effective pressure at 0.42 MPa, 0.7 MPa and 0.9 MPa, respectively. Methanol substitution ratio (MSR) was defined as the torque output contributed by methanol to the total torque output, and in this study, three MSRs (0 %, 20 %, and 40 %) were defined. Diesel–polyoxymethylene dimethyl ether (PODE) blend was defined as P50 (50 % diesel and 50 % PODE by volume) to clarify the effect of PODE addition on engine performance. The results showed that the dual-fuel engine fueled with P50/methanol had a higher peak cylinder pressure, lower first peak heat release rate (HRR), and higher second peak HRR than the dual-fuel engine fueled with diesel/methanol. Both the ignition delay and combustion duration of the dual-fuel engine decreased when the pilot fuel injection changed from diesel to P50. Moreover, both NOx emissions and particulate matter produced by the P50/methanol engine were lower than those produced by the diesel/methanol engine for the specific MSR and engine load.

Research on the Characteristics of Operating Non-Uniformity of a High-Pressure Common-Rail Diesel Engine Based on Crankshaft Segment Signals

This paper studies the operating uniformity of a high-pressure common-rail diesel engine based on crankshaft segment signals. Engine nonuniformity or unevenness refers to the crankshaft torque fluctuation caused by cylinder-to-cylinder differences, which are caused by misfiring or difference in fuel supply or air supply. The experiments were conducted on a diesel engine of the YN30CR model. Based on the relationships among the cylinder pressure, the instantaneous crankshaft angular speed, and the crankshaft segment signal, it is found that the crankshaft segment signal can be used to characterize the operating nonuniformity of the diesel engine. Based on the Fast Fourier Transformation (FFT) from the angular domain to the frequency domain in analyzing the fluctuation patterns of the crankshaft segment signals at different operating conditions, the nonuniformity information was extracted. In order to further reveal the relationship between the fluctuation phenomena of the crankshaft segment signal and the cause of the fluctuation, the torque acting on the crankshaft of the multi-cylinder diesel engine was studied to quantify the operating nonuniformity of the diesel engine. The results show that the crankshaft segment signal can reflect the uniformity of the engine torque very well in both phase and amplitude, and the degree of nonuniformity of the engine torque can be reflected by the amplitudes of the low-order non-dominant harmonics of the crankshaft segment signal below the firing frequency. The crankshaft segment signal is very consistent with the variation pattern of the engine torque.

Designing bio-diesel fuel popularization in Vietnam with suitable material selection, processing high quality bio-diesel by co-solvent method, and common-rail diesel engine endurance test

Designing bio-diesel fuel popularization in Vietnam with suitable material selection, processing high quality bio-diesel by co-solvent method, and common-rail diesel engine endurance test

Analysis of out-of-round deformation of a dry cylinder liner of a non-road high-pressure common-rail diesel engine based on multi-field coupling

The deformation of cylinder liner directly affects the sealing performance of the friction components in internal combustion engines, resulting in high oil consumption, engine power loss, and high-particulate matter emissions. Previous research works focused more on deformation of the wet vehicular cylinder liners, however, the effects of different loads on the dry liner deformation is not clear yet. A non-road high-pressure common-rail diesel engine was selected as the research object, and a coupled model of the engine was developed based on fluid–solid coupled heat transfer theory. After the accuracy of the model was verified by temperature measurement of the cylinder head and cylinder liner, deformation of the dry cylinder liner was studied. The results show that the axial and radial deformations of the cylinder liner are not uniform under the bolt preload condition. Large deformation occurs at the first liner and fourth liner, with the maximum deformation occurring at the top of fourth liner for 10.14 μm. Under the condition of thermal load, the temperature of cylinder liner exhibits a distribution of three-segments from the top to bottom. The liner deformation is not uniform, and the maximum deformation occurs at the top of the fourth liner for 304 μm. The radial deformations of all four cylinder liners present a symmetrical structure of a “heart” shape with respect to the centerline of the second and third cylinders. The axial deformation of each liner exhibits a “barrel” shape which is convex in the middle and narrow at the two ends.

Effects of diesel pre-injection on the combustion and emission characteristics of a common-rail diesel engine fueled with diesel-methanol dual-fuel

Abstract The diesel-methanol dual-fuel (DMDF) combustion was performed on a six-cylinder, common-rail diesel engine. To this end, methanol was premixed with air in the intake pipe and ignited by the directly injected diesel fuel in the cylinder. Single and double injection were considered in this study. Double injection included pre-injection and then main injection. The aim was to investigate, in comparison with the single injection strategy, what effects diesel pre-injection strategy may have on the combustion and emission characteristics of the test DMDF engine. The experiment was carried out at 1400r/min, 50% load and different values of the co-combustion ratio. The results show that, for double injection compared with single injection mode, both the heat release rate and the maximum cylinder temperature become lower, while the cycle-to-cycle variation of indicated mean effective pressure becomes higher. The results of emission characteristics indicate that, under double injection mode, the HC emissions decrease, while those of CO, NOx and PM increase. The NOx emissions and the size of particular matter both increase with co-combustion ratio, when diesel pre-injection was applied.

Oxidation behaviors and nanostructure of particulate matter produced from a diesel engine fueled with n-pentanol and 2-ethylhexyl nitrate additives

Abstract Experiments were performed on a high pressure common-rail diesel engine fueled with D100 (diesel fuel), DP15 (15% n-pentanol and 85% diesel, v/v), DP30 (30% n-pentanol and 70% diesel, v/v), DP30E1 (DP30 and 1000 ppm EHN) and DP30E2 (DP30 and 2000 ppm EHN), respectively. Particulates were sampled from the engine exhaust tailpipe and further analyzed with transmission electron microscope (TEM), Raman spectroscopy (RS) and thermogravimetric analysis (TGA). Results showed that an increase in soot oxidation reactivity was observed with increasing n-pentanol concentration in diesel/n-pentanol mixtures. This trend was in line with the poorer structural ordering of soot particles generated from blended fuels by both TEM and RS analyses. Regarding the impact of EHN addition to DP30 fuel, the soot oxidation reactivity decreased as the fuel was changed from DP30 to DP30E1, and then increased as the fuel was changed from DP30E1 to DP30E2. Notably, the soot from DP30 + EHN additive was easier to be oxidized than that from DP30. Similarly, the trends in soot oxidation reactivity with EHN additive can qualitatively capture the variations in soot nanostructure. The correlation between soot reactivity and nanostructure in this study was nonlinear, which infers that soot oxidation reactivity would be also influenced by other features like active surface area and surface functional group. It can be suggested that the application of DP30 would significantly affect the regeneration performance of diesel particulate filter (DPF); when the baseline fuel is DP30, the impacts of EHN additives on regeneration performance of DPF are relatively slight.

Effects of Ethanol, n-Butanol, and n-Pentanol Addition to Diesel Fuel on Combustion and Emission Characteristics in a Common-Rail Diesel Engine with Exhaust-Gas Recirculation

AbstractThe study aims to evaluate the combined effects of alcohols as additives to diesel and exhaust-gas recirculation (EGR) on combustion and emission characteristics of a common-rail diesel eng...

Performance and emissions of hydrogen-diesel dual direct injection (H2DDI) in a single-cylinder compression-ignition engine

Abstract Hydrogen-diesel dual direct-injection (H2DDI) is successfully implemented in a compression-ignition engine, which is developed to circumvent the pre-ignition and knocking limitations inherent to port fuel-injection hydrogen engines. An automotive-size single-cylinder common-rail diesel engine was modified to fit an additional high-pressure hydrogen injector in the cylinder head. The engine is operated at intermediate load with constant fuel-energy input using an energy-substitution principle – the diesel injection duration is decreased as the hydrogen amount is increased while adjusting the diesel injection timing to fix the combustion phasing. The results show that, at early hydrogen injection timings, the heat release rate and engine-out emissions show trends indicating premixed combustion whereas later injection timings exhibit hydrogen mixing-controlled combustion behaviour. At 50% hydrogen substitution ratio and optimised direct injection timing of 40 ⁰CA bTDC, the uncompromised indicated efficiency of 47% is achieved while the combustion-induced noise is decreased by 6 dB and the engine-out NOx emission is kept below 11 g/kWh.

Cold-start NOx emissions: Diesel and waste lubricating oil as a fuel additive

NOx emissions from diesel engines are a concern from both environmental and health perspectives. Recently this attention has targeted cold-start emissions highlighting that emission after-treatment systems are not effective in this period. Using a 6-cylinder, turbocharged, common-rail diesel engine, the current research investigates NOx emissions during cold-start using different engine performance parameters. In addition, it studies the influence of waste lubricating oil on NOx emissions introducing it as a fuel additive (1 and 5% by volume). To interpret the NOx formation, this study evaluates different parameters: exhaust gas temperature, engine oil temperature, engine coolant temperature, start of injection/combustion, in-cylinder pressure, heat release rate, maximum in-cylinder pressure and maximum rate of pressure rise. This study clarified how cold-start NOx increases as the engine is warming up while in general cold-start NOx is higher than hot-start. Results showed that in comparison with warmed up condition, during cold-start NOx, maximum in-cylinder pressure and maximum rate of pressure rise were higher; while start of injection, start of combustion and ignition delay were lower. During cold-start increased engine temperature was associated with decreasing maximum rate of pressure rise and peak apparent heat release rate. During cold-start NOx increased with temperature and it dropped sharply due to the delayed start of injection. This study also showed that using waste lubricating oil decreased NOx and maximum rate of pressure rise; and increased maximum in-cylinder pressure. NOx had a direct correlation with the maximum rate of pressure rise; and an inverse correlation with the maximum in-cylinder pressure.

Effects of PODE/diesel blends on particulate matter emission and particle oxidation characteristics of a common-rail diesel engine

The current study focused on the particulate matter emissions of polyoxymethylene dimethyl ethers (PODE)/diesel blends with PODE blending ratios of 0, 10%, 20% and 30% have been experimentally investigated in a common-rail engine. The influences of PODE blending ratio on the smoke emission, particle size distribution and particle oxidation characteristic are discussed. Results show that the addition of PODE in diesel fuel can effectively reduce smoke emission and its decreasing range becomes larger with increasing PODE blending ratio. With the increment in PODE blending ratio, the particle concentration distribution moves towards the direction of small particle size, and the total particle number concentrations decrease. Besides, the peak values of particle number concentration, surface area concentration, and volume concentration are all decreased. Adding PODE in diesel fuel increases the soluble organic fraction (SOF) content of particles, rises maximum weight loss rate of particles, and lower the peak temperature of particles. Also, the activation energy of pyrolysis reaction of particles decreases, which indicates that the oxidation of particles becomes easier as PODE blending ratio increases. The apparent morphology of particles was measured by scanning electron microscope, and the results show that the morphology of particles sample are mostly chain like or flocculent. • PODE/diesel blends can effectively reduce smoke emission, especially at high load. • The addition of PODE will decrease diesel particle size and total particle number. • PODE/diesel blends reduce particle surface area and particle volume concentrations. • PODE/diesel blends increase SOF content and decrease activation energy of particles.

The effects of EGR rates and ternary blends of biodiesel/n-pentanol/diesel on the combustion and emission characteristics of a CRDI diesel engine

An experiment was conducted to investigate the combined impacts of biodiesel and n-pentanol properties on the performance and emissions of a common-rail diesel engine at different exhaust gas recirculation (EGR) rates. Tested fuels are noted as D100 (diesel fuel), B10P20 (10% biodiesel, 20% n-pentanol and 70% diesel, by vol.), B20P10 (20% biodiesel, 10% n-pentanol and 70% diesel, by vol.), P30 (30% n-pentanol and 70% diesel, by vol.) and B30 (30% biodiesel and 70% diesel, by vol.). The results indicate that compared to D100, the ignition delays of B20P10 and B30 show different results with increased EGR rates. That is, although the cetane number of B20P10 and B30 is lower, the ignition delays of B20P10 are shorter than that of D100 when the EGR rate is over 30%. The addition of n-pentanol to diesel will result in high maximum pressure rise rate, but ternary blends of biodiesel/n-pentanol /diesel can solve or alleviate the problem without obvious decrease of indicated thermal efficiency (ITE). At high EGR rates, ternary fuels shows the advantages in decreasing total hydrocarbons (THC). There is no significant difference in nitrogen oxides (NO x ) emissions for all fuels at the same EGR rate. B10P20 and B20P10 can not only reduce soot emissions but also reduce carbon monoxide (CO) emissions under different EGR rates compared with diesel. To summarize, B20P10 fuel has a better potential for combustion and emission characteristics, especially at relatively high EGR rates.

Combustion and emission characteristics of a common rail diesel engine run with n-heptanol-methyl oleate mixtures

The purpose of the current study is to inspect the influence of the addition of n-heptanol with methyl oleate biodiesel fuel at various blending ratio on the combustion and emission parameters of a common rail diesel engine to attain their optimum ratio. The n-heptanol is added at 10%, 20%, 30% and 40%, which are denoted as H10B, H20B, H30B, and H40B respectively. Studying these mixtures stability, all blends were kept under observation for more than one month, and they were stable at ambient conditions. The measured physicochemical properties of n-heptanol-methyl oleate blends show that there is a reduction in their kinematic viscosity and cetane number. The results for methyl oleate illustrate that the peak pressure is slightly decreased by about 4%, while the soot and NO x emissions are diminished by about 2% and 6% respectively compared to pure diesel fuel. The soot and NO x emission are reduced by up to 90% and 15% respectively when adding n-heptanol. The bsfc is enlarged by around 5% methyl oleate while it is enlarged by 15% for n-heptanol- methyl oleate mixtures. It can be summarized from the combustion and emission results that the proposed mixing ratio of n-heptanol and methyl oleate fuel is H20B. • A common rail diesel engine operated with methyl oleate and n-heptanol-methyl oleate mixtures. • bsfc increased by 5% when using methyl oleate and it enlarged by 15% for n-heptanol-methyl oleate blends. • p max and HRR both reduced by 4% when using n-heptanol-methyl oleate mixtures. • Soot and NO x emission diminished by 80% and 15% with n-heptanol-methyl oleate blends. • The recommended mixing dose of n-heptanol and methyl oleate blends biodiesel was H20B.

Experimental Research on Exhaust Thermal Management Control Strategy for Diesel Particular Filter Active Regeneration

The regeneration was the main barrier restricting the development of diesel particulate filter (DPF), and the exhaust thermal management control strategy are the premise of efficient DPF active regeneration. This paper took a light vehicle equipped with high-pressure common rail diesel engine as the object, studied the influences of exhaust thermal management including intake throttling, fuel injection strategies and late post injection (LPI) coupling diesel oxidation catalyst (DOC) on exhaust temperature by experiment. The results indicated that the reduction of intake throttle valve opening at low speed and light load working conditions, where the exhaust temperatures were low, could dramatically increase the exhaust temperature. With a reasonable match of fuel injection parameters, the exhaust temperature could be increased. LPI coupling DOC could have a further increment on exhaust temperature, but it would have obvious negative effects on fuel economy and hydrocarbon emissions at the same time. In this paper, a comprehensive exhaust thermal management control strategy was proposed. The test bench indicated clearly that the demand of DPF regeneration temperature can be met in most working conditions through the reasonable integrated control strategies of exhaust thermal management.

Investigation of diesel oilLPG content fuel use in heavy duty diesel engines with common rail system

In the second decade of XXI century the diesel scandal at least questioned the future of diesel. Focal point of the scandal is the real emission values of diesel engines. Consumption is a significant element of the engine operation, which cannot be indicated with merely one value. Indicating consumption characteristics is mainly possible with specific consumption, which is highly influenced by engine speed and load. A further factor influencing specific consumption is fuel supply system of the engine. Based on previous survey results and our supercharged common rail Diesel engine, we extended our research to determine how an LPG and diesel oil operation can be realised and what differences this makes concerning engine performance, fuel consumption and emission components at identical loads. Based on their results, the different operation modes were assessed. Moreover, we deliver statements concerning the usage of diesel and LPG, emission components and specific consumption.

Alexandrian Laurel for Biodiesel Production and its Biodiesel Blends on Performance, Emission and Combustion Characteristics in Common-Rail Diesel Engine

A two-step transesterification process was employed in the biodiesel production from non-edible Alexandrian Laurel. The key physicochemical properties of the Alexandrian Laurel biodiesel (ALB), diesel and blends of both fuels were compared and analyzed. The effects of blending biodiesel (ALB) and petroleum diesel on engine performance, combustion and exhaust emissions were investigated in a turbocharged, high-pressure common-rail diesel engine under six different speed operations and at full load conditions. The test fuels comprised a conventional diesel fuel and four different fuel blends of ALB. The results showed relatively close physicochemical properties of ALB and its blends when compared with petroleum diesel. However, the use of ALB-blended fuel resulted in penalties engine brake power, brake specific fuel consumption (BSFC) despite slightly improved brake thermal efficiency (BTE). Brake specific nitrogen oxide (BSNOx) was found worsened with higher ALB content in the blends. Nonetheless, consistent improvements in brake specific carbon monoxide (BSCO), brake specific carbon dioxide (BSCO2), and smoke were noticed when ALB blends were used. Additionally, ALB blends contributed to reduction in peak combustion pressure, peak heat release rate (HRR) and combustion duration. In general, the findings suggest satisfactory operation with ALB biodiesel-diesel blends in an unmodified diesel engine.

Investigating the influence of oxygenated fuel on particulate size distribution and NOX control in a common-rail diesel engine at rated EGR levels

Abstract The effect of butanol-diesel blend (B20) and different rates of exhaust gas recirculation (EGR) on particulate matter (PM) characterisation and NOX emissions were investigated in this experimental work. The different rates of EGR (0%, 15% and 30%) and oxygenated fuel (B20) were used in this study. The brake thermal efficiency (BTE) of the engine increased under without used EGR technique compared to the presence of EGR during combustion process for B20 and diesel fuel. Further, higher BTE produced during the combustion of B20 than that produced from combustion of diesel for different rates of EGR. The BSFC slightly increased with B20 combustion compared to the diesel combustion. The cylinder pressure and ROHR improved with combustion of B20 under without using EFR. The results showed that PM reduced from the combustion of B20 more than to the diesel fuel for different rates of EGR. Besides, the average of particle diameter reduced from B20 combustion by 20, 22 and 25 nm compared to the diesel by 31, 37 and 43 nm for 0%, 15% and 30% of EGR, respectively. The soot particles generated from B20 combustion are lower than to the diesel fuel combustion for different rates of EGR. Lower level of NOX emissions can be achieved with using EGR (15% and 30%) than to the without EGR technique, this effect is more clearly with oxygenated fuel. It is indicated that the EGR dramatically increase the THC and CO emissions when exceeds the 30% with no obvious influence on NOX emissions.

Effect of isopropanol and n-pentanol addition in diesel on the combustion and emission of a common rail diesel engine under pilot plus main injection strategy

Abstract In this study, isopropanol and n-pentanol are blended in diesel with 20% ratio by volume, named D80IP20 and D80NP20. Their combustion and emission performances were compared with diesel on a four cylinder common rail diesel engine under pilot plus main injection strategy. The pilot injection duration decreases and the main injection duration increases with engine loads. For test fuels, the starts of pilot and main injection and the durations of pilot injection are remained unchanged in each engine operation. D80IP20 has the longest ignition delay due to the lowest cetane number and the shortest combustion duration due to the highest fuel oxygen. However, the peak combustion temperature of D80IP20 is lower than that of D80NP20 under double injection strategy. Compared to diesel, both D80IP20 and D80NP20 obviously reduce the particle number concentrations (PNCs) and the particle volume concentrations (PVCs), while increase the NOx emissions. D80IP20 has the lowest PNCs and PVCs and its number geometric mean diameter (NGMD) and volume geometric mean diameter (VGMD) are the lowest among the three fuels. D80IP20 has higher NOx emission than diesel, but lower than D80NP20 due to lower PCT. Further, D80IP20 with 10% EGR can achieve the simultaneous reduction for NOx emission and PNCs at low and high loads compared to diesel without EGR. Results indicate that blending isopropanol in diesel has better effects in combustion improvement and emission control and is more suitable than n-pentanol under pilot plus main injection strategy.

Analysis of the Nozzle Hole Diameter Effect to Common Rail Diesel Engine Characteristics using a Calculated Model of an Internal Combustion Engine

Analysis of the Nozzle Hole Diameter Effect to Common Rail Diesel Engine Characteristics using a Calculated Model of an Internal Combustion Engine

Parametric study on effects of methanol injection timing and methanol substitution percentage on combustion and emissions of methanol/diesel dual-fuel direct injection engine at full load

The effects of methanol injection timing (MIT) and methanol substitution percentage (MSP) on the combustion and emissions of a methanol/diesel dual-fuel direct injection engine were investigated, followed by a comparative analysis with the conventional methanol/diesel dual-fuel mode. A single-cylinder, air-cooled, naturally aspirated common rail diesel engine was modified into a dual-fuel direct injection engine with a methanol direct injection system. The engine was operated at a maximum torque speed of 2500 rpm and a mean effective pressure of 0.75 MPa. The engine performance was analyzed for different methanol/diesel fuel mixtures using four MSPs: 10%, 20%, 30%, and 40%. Meanwhile, the MIT was adjusted from −60 to −300 °CA after top dead center (ATDC). The results indicated that methanol addition and retarded MIT allowed the diesel injection timing to be properly advanced. A higher MSP increased the ignition delay (CA0-10) and decreased the combustion duration (CA10-90), leading to increases in the brake thermal efficiency (BTE), coefficient of variation of the indicated mean effective pressure (IMEP) (COVIMEP), and knock intensity (KI), along with increases in the total hydrocarbon (THC) and nitrogen oxide (NOX) emissions and decreases in the carbon monoxide (CO) and soot emissions. Additionally, for a specific MSP, the retarded MIT increased the peak cylinder pressure and decreased the maximum heat release rate. Concurrently, it decreased the CA0-10 and increased the CA10-90. Moreover, increases in the BTE, COVIMEP, and KI; decreases in the THC and CO emissions; and increases in the NOX and soot emissions were achieved using the retarded MIT.