Common-rail Engine Research Articles

Comparative Analysis of Performance and Emission Characteristics of Biodiesels from Animal Fats and Vegetable Oils as Fuel for Common Rail Engines

Currently, solving global environmental problems is recognized as an important task for humanity. In particular, automobile exhaust gases, which are pointed out as the main cause of environmental pollution, are increasing environmental pollutants and pollution problems, and exhaust gas regulations are being strengthened around the world. In particular, when an engine is idling while a car is stopped and not running, a lot of fine dust and toxic gases are emitted into the atmosphere due to the unnecessary fuel consumption of the engine. These idling emissions are making the Earth’s environmental pollution more serious and depleting limited oil resources. Biodiesel, which can replace diesel fuel, generally has similar physical properties to diesel fuel, so it is receiving a lot of attention as an eco-friendly alternative fuel. Biodiesel can be extracted from various substances of vegetable or animal origin and can also be extracted from waste resources discarded in nature. In this study, we used biodiesel blended fuel (B20) in a CRDI diesel engine to study the characteristics of gases emitted during combustion in the engine’s idling state. There were a total of four types of biodiesels used in the experiment. New Soybean Oil and New Lard Oil extracted from new resources and Waste Soybean Fried Oil and Waste Barbecue Lard Oil extracted from waste resources were used, and the gaseous substances emitted during combustion with pure diesel fuel and with the biodiesels were compared and analyzed. It was confirmed that all four B20 biodiesels had a reduction effect on PM, CO, and HC emissions, excluding NOx emissions, compared to pure diesel in terms of the emissions generated during combustion under no-load idling conditions. In particular, New Soybean Oil had the highest PM reduction rate of 20.3% compared to pure diesel, and Waste Soybean Fried Oil had the highest CO and HC reduction rates of 36.6% and 19.3%, respectively. However, NOx was confirmed to be highest in New Soybean Oil, and Waste Barbecue Lard Oil was the highest in fuel consumption.

Matching analysis on flow limiting valve of marine diesel engine common rail system

The flow limiting valve (FLV) designed for the high pressure common rail fuel system (CRS) was designed, the simulation model of the FLV and electronic controlled injector is established and the injector’s model was verified by experiment data. Through simulation, the maximum cycle injection quantity (CIQ) and close flow quantity (CFQ) of the CRS matched with the FLV are verified, and the influence of key FLV’s parameters on the matching performance was analysed. The maximum CIQ is 722mm3 and the CFQ is 1194.2mm3, which can satisfy the technical requirements of the CRS under overload conditions. The closing lift and orifice diameter of the FLV has a significant impact on the CFQ, which should be carefully designed according to the technical requirements, and the dimensional tolerance and processing accuracy should be guaranteed in the production and assembly process to ensure the consistency of the CFQ.

Optimizing combustion and emissions in natural gas/diesel dual-fuel engine with pilot injection strategy

For the clean and efficient operation of agricultural power, a non-road common-rail engine was modified to achieve natural gas/diesel dual-fuel (NDDF) combustion mode. Under low load conditions, NDDF combustion deteriorates and fuel economy decreases due to lower pressure and temperature inside the cylinder. Therefore, effects of injection pressure, pilot injection timing (SOIpilot) and pilot injection quantity (Qpilot) on in-cylinder combustion, emission characteristics and fuel economy of NDDF engine with pilot injection strategy were investigated at low load. Results show that with the increment of injection pressure, the diesel fuel beam penetration distance increased, prompting the diesel more quickly and fully mixed with fresh charge. The maximum in-cylinder pressure increased, the combustion center (CA50) moved forward, the ignition delay period was shortened, and soot, HC, C2H4 and C3H6 emissions were reduced, while BTE was improved. When SOIpilot moved forward, the pilot injected diesel and natural gas were more fully mixed, which promoted the generation of activation radicals and combustion intensity of main injected diesel. Pmax first increased and then decreased, the peak value of first heat release rate (HRRP1) gradually decreased, the peak value of second heat release rate (HRRP2) continuously increased, the combustion duration decreased, and the soot, CO and HC emissions decreased. At SOIpilot = −30 °CA ATDC, unregulated emissions reached the lowest level, while BTE was 35.55 %. With the increment of Qpilot, both Pmax and HRRP1 increased, CA05 and CA50 moved forward, combustion duration was extended, COV decreased significantly, and all emissions except NOx decreased, especially aldehyde emissions.

Reductions in Energy Consumption and Emission of Harmful Exhaust Gases by Fishing Vessels

This article presents an analysis of the influence of engine types, fuel types and selected methods of fuel treatment before injection on reductions in fuel consumption and exhaust emission components. This is the first of such studies, the continuation of which will allow a comprehensive assessment of the impact of cutter operations on environmental pollution. For the selected type of cutter, EEOIs (Energy Efficiency Operational Indicators) were determined to be a measure that takes into account both fuel consumption and harmful gas compound emissions depending on the type of engine used and the type of fuel. The data necessary to prepare this analysis were obtained during operational tests carried out on selected cutters with various types of engines fuelled with liquid fuel and a new catalytic fuel treatment method developed by the authors, while for the case of using gas fuel and a common rail engine, possible effects were forecasted. The effects of engine type, years of manufacture and fuel type (liquid and gas) on fuel consumption and emissions of selected exhaust components are demonstrated. The positive effects on fuel consumption and emissions of harmful exhaust constituents obtained, under laboratory test conditions, for an engine fuelled with catalytically treated fuel have allowed further research directions to be set for cutter engines equipped with injection equipment with applied catalytic coatings.

Effect of different ammonia mixing methods for diesel ignition on combustion and emission performance of high pressure common rail engine

Ammonia is a zero-carbon fuel. Diesel/ammonia dual-fuel combustion mode can solve the problem of difficult compression ignition of pure ammonia. This article aims to explore the best mixing method and mixing ratio of ammonia fuel. The research results show that with the increase of the ammonia mixing ratio in the intake duct, the fuel consumption rate decreases by 7.71%. However, the serious ammonia escape phenomenon reaches a maximum of 37.35%, resulting in a serious decrease in power output. The cylinder temperature dropped by 197.12K, CO2 emissions decreased by 49.34%, NOx emissions decreased by 16.84%, and emissions significantly improved. When using direct injection ammonia mixing in the cylinder, as the ammonia mixing ratio increases, the explosion pressure in the cylinder decreases by 8.32%, the temperature in the cylinder decreases by 127.37K, the maximum ammonia escape is only 6.89%, CO2 emissions decreased by 88.10%, NOx emissions decrease by 75.90%, and CO2 and NOx emissions significantly decrease. Compared with the two ammonia blending methods, the direct injection ammonia blending method in the cylinder is obviously better. When the direct injection ammonia blending ratio in the cylinder is 70%, compared to the original engine, the diesel engine has the best working performance, increased power, and improved economy by 7.52%, and the proportion of ammonia escape is small. CO2 emissions are reduced by 69.05%, and NOx emissions are reduced by 29.22%. The research results of this article provide data support for achieving energy-saving, emission reduction, and low-carbon environmental protection of diesel engines.

Effects of integrated aftertreatment system on regulated and unregulated emission characteristics of non-road methanol/diesel dual-fuel engine

In order to ensure that output power, fuel economy and harmful emissions of non-road diesel engines meet the limit requirements, and reduce the dependence on fossil fuels, methanol/diesel dual-fuel combustion mode was conducted on an agricultural four-cylinder common-rail engine, and the effects of DOC + DPF + SCR aftertreatment system on overall performance and emission characteristics of dual-fuel mode were systematically investigated. Results show that dual-fuel mode can reduce both nitrogen oxide (NOx) and soot emissions, but increase nitrogen dioxide (NO2), methanol and formaldehyde (HCHO) emissions. With the increase of load, the conversion efficiency of diesel oxidation catalyst (DOC) to carbon hydrogen (HC), carbon monoxide (CO), methanol and HCHO emissions is continuously improved. DOC can increase NO2/NOx ratio for diesel mode, but reduce NO2/NOx ratio for dual-fuel mode. At full load, the average soot capture efficiency of diesel particulate filter (DPF) for dual-fuel engine is 98.84%, basically realizing zero soot emission, while the conversion efficiency of selective catalytic reduction (SCR) for NOx is 95.22%. The increase of methanol ratio can reduce NOx emissions and nitrous oxide (N2O) generation in SCR for dual-fuel mode. Under non-road steady cycle (NRSC), the maximum brake thermal efficiency (BTE) of diesel mode and dual-fuel mode are 39.4% and 41.0%, respectively. The regulation emissions of dual-fuel engine coupling with integrated DOC + DPF + SCR aftertreatment system can meet non-road Euro-V and US-Tier 4 emission standards.

On the Increase in the Renewable Fraction in Diesel Blends using Aviation Fuel in a Common Rail Engine

Biodiesel has gained wide acceptance as an alternative to petroleum-derived fuel due to its environmentally friendly characteristics such as low aromatic and sulfur content, biodegradability and low exhaust gas emission. Although many types of feedstock could be used to produce biodiesel, waste cooking or frying oil (WCO) is a promising multiple-advantage solution. However, the use of WCO biodiesel has some drawbacks: the high viscosity and the low volatility create difficulties in atomization and in fuel–air mixing. Experiments were performed to investigate the potential employment of aviation fuels in blends with biodiesel obtained from WCO, renewable diesel and petrol diesel. The objective of the research was to evaluate Jet A’s potential to improve the blend properties, thus helping to overcome the difficulties in biodiesel usage, enabling the percentage of renewable fuel in the blend to be increased and therefore allowing a reduction in the engine’s environmental impact. The experimental activity was carried out on a small-displacement, common rail diesel engine; during the tests, the engine control unit settings were unchanged, with the aim of reproducing the engine behavior when it operated with different fuels.

Experimental study on in-cylinder combustion and exhaust emissions characteristics of natural gas/diesel dual-fuel engine with single injection and split injection strategies

On a non-road, high-pressure common-rail engine, natural gas/diesel dual-fuel (NDDF) combustion mode was performed. The way natural gas energy substitution percentage (ESP) and pilot diesel injection timing affected the combustion process, emission properties and fuel economy regarding NDDF engine with single injection strategy and split injection strategy was experimentally investigated at 25% load of 1800 rpm. Results show that under the two injection strategies, as ESP increased, NDDF combustion altered from single-stage to two-stage slowly, the combustion center (CA50) was delayed, the combustion duration increased, the soot and NO emissions declined, and the brake thermal efficiency (BTE) presented an increase-to-decrease change trend. As the combustion phase of split injection strategy was wholly advanced, the ignition delay period was shortened, the cyclic coefficient of variation (COV) and HC emission declined, and the BTE elevated. Additionally, the advanced injection timing would make NDDF heat release gradually advance, resulting in advanced CA50, extended ignition delay, lengthened combustion duration, lowered unregulated emissions, and increased BTE. The increase in peak heat release rate and BTE of split injection strategy was accompanied by decreased HC and aldehyde emissions. For NDDF engine possessing optimized split injection strategy, the BTE reached 37.79% and the COV reached 1.49% at ESP= 60%.

Prediction of emissions and performance from transient driving cycles using stationary conditions: Study of advanced biofuels under the ETC test

This paper applies and improves a methodology for estimating engine responses from transient cycles using steady conditions according to a Design of Experiments (DoE). The fuels tested are diesel-farnesane, biodiesel from sugarcane, and diesel fuel S50. A common-rail engine and the European Transient Cycle (ETC) are considered. Two DoEs of 13 runs each were analysed: the 13 modes of the European Stationary Cycle (ESCDoE) and a 5-level Fractional Factorial Design (FFDoE). The mathematical transformation of the engine working region and the experimental data approximation were improved using chord length parameterization and tensor product surfaces, respectively. Both DoEs provide an instantaneous approximation of engine performance responses of high accuracy. However, in general, better results are obtained using the FFDoE (R2 > 0.92, but R2 > 0.84 for exergy rate) compared to the ESCDoE (R2 > 0.87, and R2 > 0.53 for exergy rate). The FFDoE is the most appropriate design for the instantaneous prediction of THC and NOx regulated emissions (R2 > 0.91) as well as for its specific (accumulated) emissions (relative error e < 11%). However, worse results are obtained for CO emissions prediction (R2 > 0.7 and e < 19.1%).

Experimental investigation on combustion characteristics and influencing factors of PODE/methanol dual-fuel engine

PODE/methanol dual-fuel combustion mode was conducted on a four-cylinder common-rail engine with PODE direct injection and methanol intake fumigation. This study is aimed to investigate the effects of methanol substitution ratio (MSR), injection timing and inlet temperature on in-cylinder combustion, emission characteristics and fuel economy of dual-fuel engine. Results show that with the increase of MSR, the ignition delay of dual-fuel engine is prolonged, and the COV increases. At medium and small loads, the peak combustion pressure decreases, and the combustion phase is delayed. At high load, the peak values of heat release rate and combustion pressure increase, combustion duration is shortened, and slight knock occurs at 40% MSR. Dual-fuel mode has benefits in reduction of NOx and soot, while increases NO2 and HCHO emissions. With the delay of injection timing, combustion duration is first prolonged and then shortened. The excessive delay of injection timing leads to increased fluctuation of combustion pressure, and partial misfire occurs. With the increase of inlet temperature, the peak values of heat release rate and combustion pressure increase significantly, combustion duration is shortened, and the COV increases. At the inlet temperature of 65 °C, methanol spontaneous combustion occurs near TDC, and thermal efficiency increases to 44.6%.

Numerical simulation and experimental investigation on pollutant emissions characteristics of PODE/methanol dual-fuel combustion

The current study focuses on the effects of methanol ratio, injection timing and intake temperature on emission performance of a common-rail engine with polyoxymethylene dimethyl ethers (PODE)/methanol dual-fuel combustion mode. Then, the numerical model of dual-fuel combustion is established using CFD software CONVERGE coupled with PODE/methanol chemical kinetic mechanism, and the distribution and evolution characteristics of important radicals, methanol and temperature fields inside cylinder are calculated and analyzed. The results show that the NOx and soot emissions of dual-fuel mode decrease by 12.4% and 26.0% compared with pure PODE at 50% load, but CO and HC emissions increase. With the methanol ratio increasing, the NO and N2O emissions decrease, while the methanol, NO2, HCHO, C2H4, CH4 and C2H6 emissions increase, and the peak HO2 mass of dual-fuel increases by 156.2% compared with pure PODE. With the advance of injection timing and the increase of intake temperature, the generation rate of H and OH radicals in dual-fuel combustion raise, the emissions of NO and NO2 increase, while the emissions of methanol, HCHO, C2H4, CH4 and C2H6 decrease. Therefore, compared with traditional diesel engine, more attention should be paid to the unregulated emissions of NO2, methanol and HCHO for PODE/methanol dual-fuel engine.

Some studies on reducing carbon dioxide emission from a CRDI engine with hydrogen and a carbon capture system

The increased use of fossil fuels in the transportation sector has led to an exponential rise of carbon dioxide in the atmosphere. The carbon dioxide (CO2) is the major cause of global warming resulting in climate change and extreme weather conditions. This study explores the ways of reducing the CO2 emission from the exhaust of a common rail engine. The reduction in CO2 emissions were achieved by a combination of methods. It includes the use of low carbon biofuels (cedarwood oil (CWO), and wintergreen oil (WGO)), induction of zero-carbon, hydrogen in the intake manifold and a zeolite-based after-treatment system. In diesel, CWO and WGO were blended 20% by volume and experiments were conducted at different load conditions. The results shows that 20% blending of winter green oil resulted in maximum CO2 reduction of 20% as compared to diesel. The emission was further reduced with the induction of hydrogen along with the after-treatment system. It is seen that a maximum of 54% reduction in CO2 emission could be achieved with the combination for WGO in comparison to diesel without much affecting the other emissions and performance parameters.

Effects of pilot injection strategy on in-cylinder combustion and emission characteristics of PODE/methanol blends

Polyoxymethylene dimethyl ethers (PODE) and methanol are both promising alternative fuels with high oxygen content, and the combustion and emission characteristics of PODE/methanol blends were investigated in a common-rail engine. The premixed charge compression ignition (PCCI) combustion was realized by appropriate match of main injection and pilot injection strategies. The effects of methanol ratio (0– 20%) on fuel economy and emissions formation were studied in conventional compression ignition (CI) and PCCI modes. The combustion and emission characteristics were improved by adjusting the pilot injection timing (−40 ~ −24 °CA ATDC) and pilot injection ratio (0– 20%). The results show that the increase of methanol ratio prolongs the ignition duration, increases the premixed combustion ratio and reduces NOx emissions. PCCI combustion increases the brake thermal efficiency (BTE) and improves the trade-off relationship between NOx and soot. The delay of pilot injection timing increases the BTE, decreases HC, CO and HCHO emissions, but increases NOx and soot emissions. The appropriate pilot injection ratio can significantly increase the BTE, and has little effect on the emission characteristics. Under the optimized pilot injection strategy and appropriate methanol ratio conditions, the maximum BTE of the blends can reach 46.58% and maintain low emission level.

Comparative study on the combustion and emissions of dual-fuel common rail engines fueled with diesel/methanol, diesel/ethanol, and diesel/n-butanol

In this article, a comparative study on the effects of energy substitution ratio (ESR) on the combustion characteristics and performance of a dual fuel engine fueled with diesel/methanol, diesel/ethanol, and diesel/n-butanol was conducted experimentally. The experiments were conducted at a fixed speed of 1600 rpm and medium load with a brake mean effective pressure of 0.921 MPa. Five ESRs namely 0% (pure diesel), 10%, 20%, 30%, and 40% were conducted. The experimental results indicated that premixed combustion of diesel was retarded and enhanced, while the diffusion combustion of diesel was accelerated and advanced after these three alcohol enrichments. The ignition delay was prolonged, whereas the combustion duration was shortened for a dual fuel engine fueled with diesel/alcohols. In addition, methanol is the most beneficial in term of prolonging ignition delay and shortening combustion duration for the specific ESR. As the ESR increased from 0% to 40%, the BTE consistently increased from 41.6% to 42.3% and 42.5% for engines fueled with diesel/methanol and diesel/ethanol, respectively. However, the BTE of diesel/n-butanol engine decreased from 41.6% to 41.1% as ESR increased from 0% to 40%. All three alcohol enrichments decreased the particle concentration in diesel engine with the increase in ESR. The higher the ESR was, the lower the NOx emissions of the diesel/methanol engine and the higher the NOx emissions of the diesel/n-butanol engine.

Designing a Smart Gateway for Data Fusion Implementation in a Distributed Electronic System Used in Automotive Industry

This paper focuses on the interdisciplinary research on the design of a smart gateway for managing the dynamic error code testing collected and generated by the Electronic Control Unit (ECU) from the automotive industry. The techniques used to exchange information between the ECU code errors and knowledge bases, based on data fusion methods, allowed us to consolidate and ensure data reliability, and then to optimize processed data in our distributed electronic systems, as the basic state for Industry 4.0 standards. At the same time, they offered optimized data packets when the gateway was tested as a service integrator for ECU maintenance. The embedded programming solutions offered us safe, reliable, and flexible data packet management results on both communication systems (Transmission Control Protocol/Internet Provider (TCP/IP) and Controller Area Network (CAN) Bus) on the Electronic Control Unit (ECU) tested for diesel, high-pressure common rail engines. The main goal of this paper is to provide a solution for a smart, hardware–software, Industry-4.0-ready gateway applicable in the automotive industry.

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

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, CH3CHO 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.

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.

Injection Strategy and EGR Optimization on a Viscosity-Improved Vegetable Oil Blend Suitable for Modern Compression Ignition Engines

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;To comply with the ambitious CO&lt;sub&gt;2&lt;/sub&gt; targets of the European Union, greenhouse gas emissions from the transport sector should be eliminated by 2050. Incremental powertrain improvement and electrification are only a part of the solution and need to be supplemented by carbon-neutral fuels. Due to the high technology readiness level, biofuels offer a short-term decarbonization measure. The high process energy demand for transesterification or hydrotreating however, hinders the well-to-wheel CO&lt;sub&gt;2&lt;/sub&gt; reduction potential of current market biodiesels. An often-raised, economically and energetically feasible alternative is to use unprocessed oils with viscosity and cold-properties improvers instead. The present work investigates the suitability of one such biofuel (Plantanol&lt;sup&gt;TM&lt;/sup&gt;) for advanced common rail engines operating in a partially premixed compression ignition mode. Preliminary investigations are carried out on a Euro VIb light-duty car engine. The main focus is on the influence of the fuel blend on the soot/NO&lt;sub&gt;X&lt;/sub&gt; emission trade-off without changing the engine control maps. Single-cylinder engine tests are then focused on the optimization potential of injection parameters and external EGR to reach optimum performance-emissions trade-off on the new fuel. The results highlight that at the factory map setting, without EGR, biofuel offers slightly reduced thermal efficiency with respect to diesel, as a joint effect of retarded combustion and elevated THC and CO emissions. NO&lt;sub&gt;X&lt;/sub&gt; emissions are reduced by 20% at both non-EGR and to 25% EGR operation. With injection parameters optimization, the combustion phasing can be adjusted to diesel-like values while keeping the NO&lt;sub&gt;X&lt;/sub&gt; reduction benefits. The tested bio-oil blend is however sensitive to EGR, where increasing the recirculation rate retards the combustion while the soot emissions increase almost five-fold over the non-EGR baseline.&lt;/div&gt;&lt;/div&gt;

Influence of Ce-based catalytic fuel on exhaust particle physicochemical properties on a common-rail engine

ABSTRACT In order to explore the changes of exhaust particulate matter (PM) with the addition of Ce-based catalyst in diesel, naphthenic acid cerium solution was selected as a fuel borne catalyst (FBC). According to Ce mass fraction of 50, 100, 150, and 300 mg/kg, the solutions were added to diesel fuel and marked as F50, F100, F150, and F300, respectively. The experiments were conducted on a four-cylinder high-pressure common-rail engine fueled with FBC fuel. The particle oxidation characteristics, soluble organic fraction (SOF) components, size distribution, and microstructure with FBC fuel were investigated. The results show that the oxidation reaction of PM shifted to the low-temperature area with increasing FBC blending ratio, and the optimum ratio of Ce element is 150 mg/kg. Compared with diesel particle sample, the number of high-carbon-atom in the SOF of FBC particles decreases and the polycyclic aromatic hydrocarbons (PAHs) decrease by 49.2%, shifting FBC particles to the smaller sizes. The peak number concentration of nucleation-mode particles increases by 8.9%, and the peak mass concentration decreases by 14.5%. The FBC particles contain Ce element mass fraction about 1.23%, and its morphology is loose and porous, besides the degree of bonding is significantly reduced.

Effects of iron-based fuel borne catalyst addition on microstructure, element composition and oxidation activity of diesel exhaust particles

Metal-based fuel borne catalysts (FBC) have been extensively studied as an effective technology to reduce diesel particles and assist diesel particulate filter (DPF) regeneration. In this study, FBC fuels were prepared with Fe element mass fractions of 0, 100, 200, 300 and 400 mg/kg (marked as Diesel, Fe100, Fe200, Fe300 and Fe400). The effects of FBC additions on fuel economy and emission characteristics were carried out on a common-rail engine. Also, particle size distribution, microstructure, surface functional groups, element content and oxidation properties of exhaust particles were systematically analyzed. Results showed that the brake thermal efficiency was improved with the addition of FBC in diesel fuel, especially at low load, and the NOx and smoke emissions showed a decreasing trend. Compared with Diesel particles, the total mass concentration and the mean particle diameter of Fe300 particles decreased, the overall particle size distribution moved from coarse mode to accumulation mode, however, the total number concentration increased. Fe300 particles had larger layer spacing and microcrystalline curvature, smaller microcrystalline size and lower graphitization. In addition, the relative contents of OH and aliphatic C–H in Fe300 particles were higher than those in Diesel particles. The relative content of C atoms in Fe300 particles decreased, while the relative content of O atoms increased. Temperature-programmed-oxidation experiments indicated that semi-volatile organic components appeared in Fe300 particles, the peak temperature of weight loss rate decreased by 131 °C as compared with Diesel particles, the activation energy was also significantly lower, and therefore the particle oxidation activity was improved.