Direct Injection Compression Ignition Research Articles

A full-parameter computational optimization of both injection parameters and injector layouts for a methanol/diesel dual-fuel direct injection compression ignition engine

Both the injection parameters and injector layouts of a methanol/diesel dual-fuel direct injection compression ignition engine operated at low loads were optimized using the genetic algorithm to achieve high fuel efficiency and low emissions simultaneously. The important parameters were identified according to the sensitivity analysis, including the in-cylinder initial temperature at intake valve closing (TIVC), methanol fraction, injection timings, and injector locations. The vaporization cooling effect of the direct-injected methanol can be compensated by elevating TIVC, so the maximum methanol fraction depends on the TIVC level. Diesel should be injected before methanol to create a high-reactivity and high-temperature region to trigger ignition efficiently. Spray included angles of diesel and methanol affect the combustion process by controlling the distributions and Overlap Degree of two fuels, and a relatively high Overlap Degree is beneficial to both combustion efficiency and fuel efficiency by targeting the spray plumes of two fuels toward the piston lip. When the methanol injector is off-center installed, the increased Overlap Degree of two fuels is helpful to improve fuel efficiency with a penalty of higher nitrogen oxides (NOx) emissions. Overall, both injectors are suggested to be centrally mounted, and a small off-center installation is allowed for two injectors without deteriorating engine performance, when the partially premixed combustion is performed with advanced injection timings.

Experimental investigation of diethyl ether (DEE) blended jack fruit peel oil (JFP) with hydrogen as a secondary fuel in dual-fuel compression ignition engines.

Jack fruit peel oil (JFPO) exhibits passive chemical characteristics; thereby, dual-fuel mode frequently involves hydrogen to address its combustion difficulties. This strategy has been gaining prominence nowadays. The present investigation investigates on the performance, emission, and combustion characteristics of a direct injected compression ignition dual-fuel engine operating on a binary fuel blend of jack fruit peel oil (JFPO) and diethyl ether with hydrogen induction. The engine was operated by inducing hydrogen gas into the intake manifold of the engine at 8 and 10 LPM with the applied load ranging from 25 to 100%. The test fuel was prepared by blending jack fruit peel oil and diethyl ether in the volumetric ratio of 90:10. JFP brake thermal efficiency was 16% lower than diesel at full load but enhanced by 9% with direct hydrogen induction at a knock limit of 10 LPM and 23% with JFP + H2 + 10% DEE at maximum load. At maximum load, JFP + 10 LPM of hydrogen gas + 10% DEE produces 916ppm of NOx, which is 44.46% less than diesel. Furthermore, adding hydrogen gas and DEE to air fuel mixture decreased emissions of carbon monoxide and unburned hydrocarbon by 0.702% and 28.30% opa, respectively.

Ignition and Combustion Characterization of Hydrogen/Methane Blends in Direct-Injection Compression-Ignition Conditions

Ignition and Combustion Characterization of Hydrogen/Methane Blends in Direct-Injection Compression-Ignition Conditions

Compression Ignition Internal Combustion Engine’s Energy Parameter Research Using Variable (HVO) Biodiesel and Biobutanol Fuel Blends

This study investigates the impact of different biofuels, such as pure hydrogenated vegetable oil, hydrogenated vegetable oil, and biobutanol, as well as their blends, on the non-energetic operational characteristics of a compression ignition internal combustion engine. The research investigations were conducted using a turbocharged direct injection compression ignition engine that was put within a Skoda Octavia 1.9 TDI automobile. Throughout the investigation, the primary emphasis was placed on analyzing energy characteristics such as power, brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), and other related factors. The analysis involved the utilization of multiple combinations of bio-based fuels, namely four mixes of HVO with biobutanol (HVO100, HVOB5, HVOB10, and HVOB20), which were subsequently compared to fossil diesel (D100). The findings of the study indicate that the utilization of HVO100 fuel results in notable reductions in power output and mass fraction when compared to D100 gasoline. HVO100 fuel demonstrates superior performance to D100 gasoline, exhibiting a range of 1.7% to 28% improvement in brake-specific fuel consumption. Additionally, at an engine speed of 4500 rpm, the use of HVO100 fuel leads to a decrease in brake thermal efficiency of 4.4%.

Comparative study on combustion and emission characteristics of gas-to-liquid with diesel on a burner and a naturally aspirated compression ignition engine

ABSTRACT Due to the consumption of fossil fuels and the generation of harmful emissions by diesel engines, researchers are seeking alternative fuels for diesel, for example, gas-to-liquid (GTL). However, most studies on combustion and emission of GTL focused on the fuel burned on turbocharged heavy-duty diesel engines. The purpose of this study is to reveal the combustion, fuel economy, and emission characteristics of GTL by a burner and a naturally aspirated (NA), fuel direct injection compression ignition light-duty engine. Comparative experiments of the GTL to fossil diesel were carried out, respectively. The burner has good consistency with the diesel engine in revealing emission trends. The results of the burner test showed that GTL produced less flame smoke and its flame height was 5.3% lower than diesel. The results of the engine bench test revealed that the combustion and emissions of the GTL with diesel were significantly different. Compared to diesel, the ignition of GTL began earlier from 1.5°CA to2.5°CA though the combustion was slower in contrast to diesel. The diffusion combustion maximum pressure was considerably 4.8% higher and occurred earlier with 2.2°CA-3°CA, and the premixed combustion peak pressure of GTL was slightly beyond the diesel. The peak of premixed combustion heat release rate (HRR) for GTL was less than that of diesel by 18.9%. While the peak HRR of diffusion combustion was greater by 38.4%. The maximum PRR value of GTL was lower than that of diesel leading to soft combustion. In all test conditions, the brake specific fuel consumption of GTL averagely reduced by 4.7% against diesel, and the brake thermal efficiency was on average 4.3% higher. GTL engine can reduce regular emissions of carbon monoxide, hydrocarbons, nitrogen oxide (NOx), smoke, and particle number (PN) simultaneously. It is worth noting that GTL improved the trade-off issue of NOx and smoke, simultaneously reducing 18.8% NOx and 24.1% smoke on average. The experimental results reveal the GTL is an appropriate alternative fuel for light-duty diesel engine without modification of mechanical fuel system.

Numerical investigation for enhancing HCCI combustion characteristics in DI-CI engine fueled with butanol/diesel blends

The fast depletion of fossil fuels and the hazardous emissions associated with the use of fossil fuels in IC engines is driving the research in the area of renewable fuels. Homogeneous charge combustion ignition (HCCI) is a new mode of engine combustion technology, used for reducing the emissions without compromising the engine performance. The combination of HCCI and alcohol/diesel blends has the potential to simultaneously address the twin problems of depletion of fossil fuels and engine emissions. Butanol is an attractive biofuel, which is produced from agriculture wastes such as sugar cane bagasses and corn stalk etc. This paper presents numerical and modeling analysis on the emission and performance characteristics of a direct injection- compression ignition (DI-CI) engine operated with butanol/diesel blends. Numerical analysis was carried out using CONVERGE CFD software. Response surface methodology (RSM) was used in developing the response models for three output parameters, viz., nitrogen oxides (NOx), soot emissions and indicated specific fuel consumption (ISFC), in terms of the four input parameters, viz., compression ratio (CR), start of injection (SOI), fuel injection pressure (FIP) and exhaust gas recirculation (EGR). Numerical experiments were conducted by varying these four input parameters, i.e., CR from 14 to 19, FIP from 200 to 280 bar, EGR from 0% to 30% and SOI from 17° to 29° CA bTDC, and with four butanol/diesel blends (0, 20%, 30% and 40% of butanol-by volume, designated as Bu00, Bu20, Bu30 and Bu40). The optimum combination of the input parameters for the four test fuels were found with the objective of minimizing the three output parameters (i.e., ISFC, soot and NOx) using desirability approach. The homogeneity of the air-fuel mixture was estimated using equivalence ratio distribution index, i.e., Target fuel distribution index (TFDI). From the numerical analysis, it was found that the TFDI improved for the optimized case by 20.5%, 21.5%, 24.4% and 27.2% for Bu00, Bu20, Bu30 and Bu40 respectively as compared to their respective baseline configuration.

Efficacy of performance and mitigate pollution of CI engine: Delonix regia biodiesel with n‐butanol and exhaust gas recirculation

AbstractThe primary aim of this research study was to examine the effectiveness and environmental consequences of using Delonix regia biodiesel (DRB) in combination with butanol (BUT), exhaust gas recirculation (EGR), and diesel fuel (D) on a direct injection compression ignition engine operating at a constant speed. This study involved the formulation of five distinct biodiesel blends, namely DRB10% + D90%, DRB20% + D80%, DRB10% + BUT10% + D80%, DRB10% + BUT20% + D70%, and DRB20% + D80% + EGR10%. The inclusion of n‐butanol in a biodiesel blend serves to tackle the problem of inadequate combustion in fuel blends by alleviating the oxygen deficiency that occurs during the combustion process. The findings of the study revealed that the combination of DRB at 10%, BUT at 20%, and D at 70% produced in a significant reduction in specific fuel consumption (SFC) by 11.19% and brake thermal efficiency by 2.62%. Additionally, this combination led to a decrease in exhaust emissions of CO and Smoke, with the exception of HC and NOx, when compared to the use of diesel fuel. The control of HC and NOx emissions can be achieved through the implementation of an exhaust gas recirculation system. The results of this investigation suggest that Delonix regia biodiesel, in combination with a 20% concentration of n‐butanol, has potential as a viable alternative fuel choice that may be utilized without necessitating any engine modifications.

Performance analysis of a diesel engine using margosa oil ethyl ester-based biodiesel with diethyl ether as an oxygenated additive

In this study, the effect of Margosa oil ethyl ester (MOEE) with oxygenated additive Diethyl ether (DEE) on the thermal performance, combustion, and emission characteristics of a direct-injection compression ignition engine (CIE) was examined. Experiments were performed under various engine loadings at a constant speed of 1500 rpm. Two-step transesterification process was followed for producing MOEE-based biodiesel from Margosa oil owing to its high free fatty acid content. Further, four different blends of MOEE and Diesel with fixed DEE concentration (5% by vol.) were fuelled in a CIE and compared its performance with Diesel. Results showed that the increase in MOEE proportion in the blends decremented the mean brake thermal efficiency and the maximum reduction was about 14.3% for MOEE20 as compared to diesel. Moreover, there was a decline in In-cylinder pressure and net heat release rate when MOEE20 fuelled in a CIE by up to 8.1% and 8.7% respectively. Emission results found that the MOEE blends emitted more oxides of nitrogen and carbon dioxide by up to 18.8% and 14.7% respectively with a major decrement in emissions of hydrocarbon by up to 41.2%. Overall, it is concluded that the fueling of MOEE20 could be the plausible option for swapping the diesel usage in CIE with an excellent reduction in emission despite a marginal drop in performance.

Numerical investigation of the effect of altitude on diesel engine combustion and soot emissions

It is increasing concerned that the plateau environment will potentially increase fuel consumption in engines. Despite this, the current state of research on high altitude engines is still inadequate in providing sufficient and detailed information to counteract the decrease in engine efficiency. In addition, one of the novelty of this study was that the investigated altitudes is up to 4500 m, of which the previous studies was limited. Therefore, this study aims to investigate the effect of altitude on in-cylinder spray, combustion, and soot formation processes in diesel engines. A calibrated three-dimensional (3D) computational fluid dynamics (CFD) model of a single-cylinder, four-strokes, direct injection (DI) compression ignition, intake boost research diesel engine is established. The numerical CFD model used in this study has been validated through comparison with experimental data. It effectively investigates the in-cylinder activities and provides insights into the causes behind combustion and soot emission deterioration. The simulation is operated at altitudes of 0, 1500, 3000, 4500 m with corresponding intake pressure. It has been observed that engine performance and soot emissions deteriorate as altitude increases, and a sharp drop occurs when the altitude exceeds 3000 m, which can be attributed to the dramatic decline in combustion efficiency. The extended spray leads to a decrease in air utilization, which ultimately results in a sudden drop in combustion efficiency at altitudes above 3000 m. Overall, this study has identified that the extended penetration of the spray, caused by reduced pressure and air density, leads to poor air utilization, resulting in decreased performance and increased emissions. Hence, it is recommended that optimization of the combustion chamber geometry and injection strategies of diesel engines operating at high altitudes be undertaken to improve air utilization and combustion quality. This will serve as an avenue for further research in the future.

Effects of hydrogen and EGR on energy efficiency improvement with ultra low emissions in a common rail direct injection compression ignition engine fueled with dimethyl ether (DME) under HCCI mode

This study deals with enhancing the energy efficiency with ultra-low emissions and extending the operating range (maximum load limit) of dimethyl ether (DME) fueled homogeneous charge compression ignition (HCCI) engine using hydrogen and exhaust gas recirculation (EGR). In the neat DME mode, the possible maximum load limit with controlled auto-ignition (CAI) was found as 24% (BMEP of 1.67 bar). Beyond 24% load, the knocking was observed with an advanced combustion phase, and shortened combustion duration resulted in uncontrolled auto-ignition (UAI) combustion. The addition of EGR extended the maximum load limit to 52% (BMEP of 3.62 bar) (60% EGR). Near-zero levels of NOx, zero smoke, and marginal CO and HC emissions reduction were observed with the optimized EGR rate (35%). The hydrogen fuel addition along with DME at an optimized EGR rate resulted in combustion phase retardation with the elimination of the low-temperature reaction (LTR) region. The energy efficiency (EE) and indicated thermal efficiency (ITE) increased along with zero smoke emission, ultra-low NOx, CO, and HC, and lower CO2 emissions till 12% of hydrogen energy share (HES). Thus, the combined strategy of EGR and hydrogen could effectively extend the operating range with ultra-low emissions levels.

Modelling of multiple biodiesel-emitted nitrogen oxides using ANN approach

This research paper focuses on modelling of nitrogen oxides emitted by diesel engine for multiple biodiesel blends. A lot of research work has observed that the properties of biodiesel blends affect the nitrogen oxide emissions. To this aim, total of fifteen blends of multiple biodiesels are prepared on vol. % by using four non-edible category biodiesels. The suitability and quality of the biodiesel and diesel blends are tested through a characterization and found within the permissible limits of ASTM. The experimentation has been carried out on a direct injection compression ignition (DICI) engine with constant speed and varying loading condition from no load to full load in a step of 25%. During the experimentation, the NOx emissions are measured using a Netel MGA-2 exhaust gas analyzer. The study revealed that several properties such as viscosity, density, mean gas temperature, etc. affect NOx emission. In addition, NOx emission increases with an increase in BPs. The artificial neural network (ANN) is performed by considering physicochemical and thermal properties as a function. The ANN predicts the estimated NOx with an accuracy of 0.99.

Hydrogen influence on kapok methyl ester blended with DEE as an alternate fuel in CI engine

Kapok oil methyl ester (KOME) is used as a pilot fuel, while hydrogen and diethyl ether (DEE) are used as secondary fuels to improve the performance, emissions and combustion of a direct injection compression ignition engine. With a compression ignition engine, a slight modification to the system enables hydrogen gas through the intake manifold. A flow metre limits the quantity of energy the hydrogen may produce off, and two flame arresters prevent backfires in the fuel line. At full load and maximum hydrogen energy sharing, KOME + 20%DEE obtained a brake thermal efficiency of 30.31%, which is 14% higher than without hydrogen enrichment and about 8% higher than diesel's value (0% hydrogen energy share). The main problem with previous research is that hydrogen with a high heating value makes greater amounts of nitric oxide. Diethyl ether, on the other hand, has fixed this major problem, and the absence of carbon in hydrogen fuel lowers CO, HC and smoke emissions.

Effect of green fuel and green lubricant with metallic nanoparticles on emissions of HC, CO, NOx, and smoke for a compression ignition engine

The United Nations Sustainable Development Goals (SDGs) are imperative from the point of view of protecting the environment by employing sustainable options. Considerable research has been carried out in the transportation sector to meet this objective. Here, the influence is assessed of epoxidised gingelly oil methyl ester biolubricant with alumina (Al2O3) nanoparticles on the performance and emissions of a single cylinder 0.66-L capacity direct injection compression ignition engine driven by gingelly B20 biodiesel. Engine tests are carried out with gingelly B20 biodiesel as a fuel, and gingelly methyl ester (B100), epoxidised gingelly methyl ester (B100E), and epoxidised gingelly methyl ester (B100E) mixed with 0.5%, 1.0%, and 1.5% w/w alumina (Al2O3) nanoparticles as the lubricant combinations. The results are compared with baseline B20 biodiesel fuel-mineral lubricant operation. The findings indicate that brake thermal efficiency increases by 8.64% for epoxidised gingelly methyl ester (B100E) with 1.0% w/w alumina (Al2O3) nanoparticle biolubricant in comparison to baseline operation. Considerable reductions in emissions are detected; specifically, reductions of 52.4%, 22.0%, 20.0%, and 34.9%, respectively, are observed for CO, NOx, and HC concentrations and smoke opacity for the abovementioned combination as compared to baseline operation. The present work suggests that further research is merited on green fuel-green lubricant combinations. The findings of this study address the United Nations Sustainable Development Goals (SDGs) 7 and 13.

Sustainable nano-added biofuel production from borassus flabellifer oil for conventional internal combustion engines

The source of biodiesel production is significant as the demand for diesel is very high. Sustainable fuel development is the prime aim of meeting the demand. Drought-tolerant trees are widely available and can cultivate more to increase the feedstock capacity. Hence, this experimental research investigates the potential for deriving an alternative fuel from borassus flabellifer. Accordingly, this research employed biodiesel production from borassus flabellifer oil through the transesterification technique with methanol at 65 °C of temperature for 3 h with 300 rpm of magnetic stirrer speed. The blends by volume of 20% biodiesel of borassus flabellifer (20BOPP) and 80% of diesel (80D) were used to create the Biodiesel of borassus flabellifer blend (20BOPP+80D). Then it is enhanced by mixing 100 ppm of aluminium oxide nanoparticles (AONP) in that fuel to produce the nano-fuel of 20BOPP+80D + AONP. The base fuel (20BOPP) is enhanced by preparing a new blend of 20% ethanol (20 E) and 60% diesel added with 20BOPP to produce 20BOPP+20E+60D and then the new class of fuel enhanced by AONP to produce 20BOPP+20E+60D + AONP. The nano-fuel was prepared with the help of an ultrasonicator. The prepared blends and conventional diesel fuel were tested at varying engine loads, and the results revealed that the enhanced nonfuel of 20BOPP+20E+60D + AONP produced equivalent brake thermal efficiency (BTE) of 31.94% like diesel fuel, reducing the emission nitrogen oxides (NOx) by 29.2% and emission of Carbon Monoxide (CO) emission by 11.4% to pure diesel fuel. The enhanced nano-fuel of 20BOPP+20E+60D + AONP reduced smoke opacity by 35.3% more than pure diesel. Hence the mixing of both alcohol and nanoparticles in the biodiesel blend produces better results at maximum load conditions than their performance mixing individually in the biodiesel blend due to the alcohol's higher volatility and nanoparticles catalytic reaction during combustion in the Direct-Injection Compression Ignition (DICI) engine due to the alcohol's higher volatility and nanoparticles catalytic reaction during combustion stage.

Simulations of ammonia spray evaporation, cooling, mixture formation and combustion in a direct injection compression ignition engine

This study investigates the novel approach of direct liquid ammonia injection into the combustion chamber of a compression ignition engine. Unlike traditional gaseous ammonia port injection, this method shows promise in reducing ammonia slip and emissions. To simulate and analyze the behavior of the liquid ammonia spray, we employed numerical models based on existing literature on flashing and non-flashing spray simulations, as well as recent experimental studies on ammonia spray characteristics using a gasoline direct injection (GDI) injector. Our approach utilized a Lagrangian discrete phase modelling technique to perform a series of three-dimensional computational fluid dynamics (CFD) simulations. The primary objectives of this research were to evaluate the evaporation process of ammonia and its cooling effect, as well as to gain insights into mixture formation within the engine cylinder under different operating conditions. The simulations encompassed the entire engine cycle, considering a multi-hole GDI ammonia spray in conjunction with pilot n-heptane, a diesel surrogate, in equal proportions on an energy basis. Three distinct injection timings for ammonia were examined, leading to varying thermodynamic conditions within the combustion chamber during each spray formation. Consequently, different modelling parameters and initial conditions were necessary to accurately replicate the spray behavior. To address this, we proposed a systematic procedure for assigning pre-defined spray angles. The non-reacting, evaporating spray simulations yielded valuable insights into the mixture formation process, which guided our analysis. Finally, reacting conditions were considered to evaluate engine performance and resulting exhaust gas emissions. This study provides a comprehensive overview of critical aspects related to direct ammonia injection in internal combustion engine (ICE) systems. Moreover, it uncovers performance trends that can serve as a foundation for future investigations in this field.

Analysis of CRDI diesel engine characteristics operated on dual fuel mode fueled with biodiesel-hydrogen enriched producer gas under the single and multi-injection scheme

The present work aims to investigate the consequences of pilot fuel (PF) multiple injections and hydrogen manifold injection (HMI) on the combustion and tailpipe gas characteristics of a common rail direct injection (CRDI) compression ignition (CI) engine operated on dual fuel (DF) mode. The CI engine can perform on a wide variety of fuels and under high pilot fuel (PF) pressure. Pilot fuel injection (PFI) is achieved at TDC, 5, 10, and 15ºCA before the top dead center (bTDC), and divided injection consists of injecting fuel in three different magnitudes on a time basis and PF is injected into the engine cylinder at a pressure of 600 bar. In this work, the hydrogen flow rate (HFR) was fixed at 8 lpm constant and producer gas was inducted without any restriction. The investigational engine setup has the ability to deliver a PF and hydrogen (H2) precisely in all operating circumstances using a separate electronic control unit (ECU). Results showed that diesel-hydrogen enriched producer gas (HPG) operation at maximum operating conditions provided amplified thermal efficiency by 4.01% with reduced emissions, except NOx levels, compared to biodiesel-HPG operation. Further, DiSOME with the multi-injection strategy of 60 + 20+20 and 50 + 25+25, lowered thermal efficiency by 4.8% and 9.12%, respectively compared to identical fuel combinations under a single injection scheme. However, reductions in NOx levels, cylinder pressure, and HRR were observed with a multi-injection scheme. It is concluded that multi-injection results in lower BTE, changes carbon-based emissions marginally, and decreases cylinder pressure and heat release rate than the traditional fuel injection method.

Numerical study of heat transfer of hydrogen combustion in noble gases atmosphere in compression ignition engine

The high energy content of hydrogen and zero carbon emission from hydrogen combustion is very important for compression ignition engine development. Hydrogen requires a very high auto-ignition temperature, which encourages replacing nitrogen with noble gases with higher specific heat ratio during compression process. In noble gases-hydrogen combustion, higher combustion temperature potentially leading to a higher heat loss. This paper aims to investigate the effect of hydrogen combustion in various noble gases on heat distribution and heat transfer on the cylinder wall. Converge CFD software was used to simulate a Yanmar NF19SK direct injection compression ignition engine. The local heat flux was measured at different locations of cylinder wall and piston head. The heat transfer of hydrogen combustion in various noble gases at different intake temperatures was studied using the numerical approach. As a result, hydrogen combustion in light noble gases such as helium produces faster combustion progress and higher heat temperature. The hydrogen combustion that experienced detonation, which happened in neon at 340 K and argon at 380 K, recorded a very high local heat flux at the cylinder head and piston due to the rapid combustion, which should be avoided in the engine operation. At a higher intake temperature, the rate of heat transfer on the cylinder wall is increased. In conclusion, helium was found as the best working gas for controlling combustion and heat transfer. Overall, the heat transfer data gained in this paper can be used to construct the future engine hydrogen in noble gases.

An experimental investigation of new chamber geometry on the combustion characteristics, performance and emissions in a light-duty diesel engine

Piston bowl geometry directly affects many parameters such as combustion, flow, turbulence, and mixture formation in-cylinder. This causes a change in engine performance, combustion characteristics and exhaust emissions. In the present study, the effects of piston bowl geometry on mixture formation, combustion characteristics, and emission characteristics of a direct injection compression ignition engine have been experimentally tested. Novel bowl geometries namely New Combustion Chamber (NCC) were developed and made comparison Standard Combustion Chamber (SCC). Air-cooled, four-stroke, single-cylinder and direct injection compression ignition engine was used in the experiments. The diesel engine was operated under full load and different speed conditions (1800, 1900, 2000, 2100 and 2200 rpm). Within the scope of the study, brake specific fuel consumption, engine torque, exhaust emissions (CO2, CO, O2, HC, NO and soot) and combustion characteristics (Instantaneous heat release rate, in-cylinder pressure change, rate of pressure rise and mass fraction burned) were examined. The results showed that the eight pockets and sub-base radius in the NCC geometry significantly improved the specified parameters. The NCC geometry according to the SCC, the specific fuel consumption decreased by approximately 6.89% and engine torque increase 6.32% in the achieved maximum torque at 2000 rpm. Exhaust emissions are generally reduced thanks to the NCC bowl geometry. However, NO emissions increased due to increased temperatures, improved combustion and mixture formation at all speeds. When the combustion analyzes were examined, it was seen that the new type of bowl improved the combustion. The reason was that the increase of the bowl in the surface area, and the increased turbulence with it provided easier evaporation of the fuel droplets and better mixture formation with the air. The spread of combustion over a large area causes an increase in the flame surface area and more controlled combustion was achieved.

Comparative Performance Assessment of Adsorbents for CO2 Capture via Physisorption in a Diesel Engine Exhaust

AbstractThe atmospheric carbon dioxide (CO2) concentration has been consistently increasing each year throughout the world. Internal combustion (IC) engines are significant contributors to CO2 emissions. This study explores the possibility of employing effective biomass‐based adsorbents to mitigate CO2 from a diesel engine exhaust. As a first step, two distinct agro‐wastes, namely, i) corn cob and ii) sugarcane bagasse, are used to prepare inexpensive and efficient activated carbons. The two main steps in the activated carbon preparation are a) carbonization and b) activation. The derived activated carbons are subjected to discrete analytical techniques to examine their structural and textural characteristics, surface functional groups, and physical, chemical, and adsorptive properties. As a second step, the exhaust treatment chamber unit is filled with the adsorbents one by one and is connected to the exhaust of the constant pressure heat addition engine. A single‐cylinder, four‐stroke, naturally‐aspirated, air‐cooled, direct injection (DI) compression ignition (CI) engine is used in the experimental investigations. The essential findings show that ≈68 and 60% of CO2 emissions are adsorbed in the test engine by utilizing corn cob and sugarcane bagasse adsorbents, respectively. The results show that during the D100 and JME20 operations, the prospective adsorbents can curb more than 40% of overall CO2 emissions.

A novel coffea leaf pigment doped Phoenix dactylifera L biodiesel and its performance characteristics on a direct injection compression ignition engine

The instability of biodiesel fuels during storage is a key issue. In this work, biodiesel has derived from Phoenix dactylifera L (Date seed) is doped with CLP in various concentrations from 500 ppm to 2000 ppm to improve storage stability. Doping the samples with coffea leaf pigment made them more stable than plain biodiesel fuel. Using 2000 ppm of CLP in the DS (B20), engine testing proves that the addition of antioxidants improves engine performance to a considerable extent. The performance, combustion, and emission experiments were performed on the DICI engine by fueling with DS doped with CLP antioxidant additives. Brake thermal efficiency was found to increase for all test blends with respect to load due to the increased power output at higher loading conditions. However, the biodiesel with antioxidant-doped blends depicted a declining trend in brake thermal efficiency at all loading conditions. The biodiesel blend doped with antioxidant additives reduces the degree of oxidation of fuel molecules thereby restricting the combustion temperature where reduces the BTE. On analyzing the emission characteristics, the antioxidant addition diminishes the free radical sites and kerbs the oxidation reaction thereby augmenting CO and HC emissions. Emission of HC augmented on adding of CLP concentration in biodiesel due to the retarded oxidation of the hydrocarbon chain as a result of antioxidant addition. On the other hand, a reduction in combustion temperature leads to a reduction of NOX emissions for all the antioxidant-doped blends as oxidation of nitrogen is curbed by restricting the free radical sites and quenching the combustion temperature.