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When compared to other internal combustion engine types (SI engine, CI engine), the gasoline compression ignition engine (GCI engine) offers a promising and efficient way to enhance heat efficiency and less harmful emissions. The development of new engine technologies is aimed at optimizing the performance of GCI engines by allowing them to operate more efficiently at part load and using lower octane gasoline fuel under higher compression ratios. The GCI engine struggles to cope with a large amount of smoke, soot, HC and CO, and it is not very stable when operating at a low load or when it is exposed to high load conditions, which can cause autoignition. This study will introduce certain technologies, such the strategy for dealing with exhaust gas recirculation (EGR) and oxygen content, that assist in resolving the issues faced by the GCI engine. The research results show that the ignition delay tends to decrease with an increase in EGR. The ignition delay reaches its minimum value at 20% EGR with GB05 fuel. The maximum pressure in the combustion chamber of a GB05-fueled engine can be improved at 20% EGR. The engine's thermal efficiency and NOx emissions decrease, while CO and HC emissions increase with increasing EGR. The increase in oxygen content led to a decrease in ignition delay and lift-off length. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the interrelationships between key harmful emission components, nitrogen oxides (NOx), and particulate numbers (PNs) in diesel engine exhaust and the control actuators of diesel engines. This research involved conducting a series of experiments under fixed parameters within an engine brake laboratory environment to elucidate these correlations. The objectives of this study were to conduct a comprehensive review of the relevant emissions technology literature and a comparative assessment of particle measurement methods based on dilution ratios and develop innovative aerosol preparation principles tailored to condensation particle measurement. Additionally, this research involved designing and implementing an aerosol preparation unit based on the newly developed principles, along with the creation of test cell control programs using the AVL PUMA Open TST editor interface and Visual Basic. Furthermore, this study was concerned with conducting evaluations of fixed-parameter engine dynamometer tests to explore the functional relationships between the emission of 10/23 nm particles, NOx emissions, common rail pressure variations, and exhaust gas recirculation levels. This study aimed to enhance the understanding of diesel engine emissions dynamics and contribute valuable insights for developing more efficient and environmentally friendly engine control strategies. [ABSTRACT FROM AUTHOR]

In this article, the authors refer to the measurement of acoustic emission, where they found that this methodology can determine the combustion characteristics in the combustion chamber of the engine and thus it is possible to confirm a better combustion process and overall reduction of engine noise after decarbonization. The formation of diesel exhaust soot is also supported by the authors' paper, in which they describe how such soot is formed and what effect the addition of special mixtures to the combustion process has on the formation of such carbon deposits. The article uses BG technologies for deep engine decarbonization, including intake and exhaust parts. This technology is one of many on the market, but it was only with this technology that the authors managed to achieve the relevant results that this article will introduce to. For the test, we selected vehicles that had a problem to pass at the emission control. [ABSTRACT FROM AUTHOR]

The 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. [ABSTRACT FROM AUTHOR]

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 NO x , 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 NO x , CO, and HC, and lower CO 2 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. • EGR extended the maximum load limit and control knock in DME HCCI engine. • Higher energy efficiency and indicated thermal efficiency with hydrogen. • Zero smoke emission with Ultra-Low NO x , CO, CO 2 , and HC emissions. • Elimination of cool-flame (LTR) region with hydrogen. • DME and hydrogen could be a dual fuel combination for HCCI combustion. [ABSTRACT FROM AUTHOR]

In this present work, the impacts of exhaust gas recirculation (EGR) on exhaust emissions of a diesel engine powered with the blending of butanol with mineral diesel under different engine loads were studied. Experimental tests were performed using butanol‐diesel blends on a single cylinder, constant speed, direct injection (DI) unmodified diesel engine at different proportions by vol%. A higher alcohol—Butanol of 10%, 20%, and 30% blended with mineral diesel fuel. Three different EGR rates of 10 to 30% were employed to reduce the oxides of nitrogen (NOx) emissions that prevailed at higher engine loads. Experimental results revealed that by increasing the EGR rates reduces nitrogen oxide emissions by up to 32% at higher loads. Whereas smoke opacity barely raised to an EGR rate of 20%. There was a rise in hydrocarbon (HC) emissions and a slight surge in carbon monoxide (CO) emissions found with butanol‐diesel blends rather than mineral diesel. NOx emissions were decreased by 29% for 70% Diesel + 30% Butanol (Bu30) blend with EGR 30% than mineral diesel fuel. There is an increase in smoke opacity with engine load because of the burning of a higher amount of energy to generate higher brake power. Smoke opacity is decreased to 68.9% using Bu30 than conventional diesel. Overall, it was found that blends of 30% of butanol and 70% of diesel can be employed in existing unmodified diesel engines. [ABSTRACT FROM AUTHOR]

The efficient application of oxygen-containing clean fuels in engines has always been a research focus. With the increase in ethanol production, the output of fusel as a co-product is also increasing. The application of fusel is also an effective way to lessen the consumption of fossil fuels. Therefore, the influences of fusel on performance and emissions were investigated in the current study on a six-cylinder heavy-duty compression-ignition engine and revolved around the WHSC test cycle. The three test fuels were diesel, F20NW (the volume proportion of anhydrous fusel is 20%, and the rest is pure diesel), and F20WW (the volume proportion of hydrous fusel is 20%). The addition of fusel improved BTE, reduced NOx and soot emissions, and thermal efficiency and emissions were further improved in combination with EGR optimization. In terms of WHSC, the improvement effect of hydrous fusel was the best. The equivalent fuel consumption, NOx, soot, and CO2 emissions of F20WW were reduced by 1.77%, 37.49%, 17.38%, and 1.32%, respectively, with the optimization of EGR compared with pure diesel. The addition of 20% hydrous fusel combined with the introduction of EGR can be directly applied to existing diesel engines and achieve a simultaneous reduction in fuel consumption and emissions. [ABSTRACT FROM AUTHOR]

The present study investigated the effect of compression ratio (CR) with the use of exhaust gas recirculation (EGR) technology on the performance of combustion characteristics at different CRs and engine loads; the brake thermal efficiency (BTE), specific fuel consumption (SFC), volumetric efficiency (VOL.EFF), exhaust gas temperature, carbon dioxide emission (CO2), hydrocarbons (HC), nitrogen oxides (NOx), and oxygen content (O2). The single‐cylinder, four‐stroke compression ignition engine was run on a mixture of diesel and biodiesel prepared from Iraqi waste cooking oil at (B0, B10, B20, and B30). A comparison has been achieved for these combustion characteristics at different blends, load, and CRs (14.5, 15.5, and 16.5) at 1500 rpm constant engine speed. The transesterification process is used to produce biodiesel and ASTM standards have been used to determine the physical and chemical properties of biodiesel and compare them to net diesel fuel. The preliminary conducting tests indicated that engine performance and emissions improved with the B20 mixture. Experimental test results showed an increase in BTE when CR increased by 17% and SFC increased by 23%. It also found a higher VOL.EFF by 6% at higher pressure ratios. A continuous decrease in BTE values and an increase in SFC were sustained when the percentage of biodiesel in the mixture was increased. Emissions of carbon dioxide, HC, and NOx increased by 12%, 50%, and 40%, respectively, as CR reached high values. NOx increased with the addition of biodiesel to 35%, which necessitated the use of EGR technology at rates of 5% and 10%. The results indicated that the best results were obtained in the case of running the engine with a mixing ratio of B20 with the addition of 10% EGR, NOx decreased by 47% against a slight increase in other emissions. [ABSTRACT FROM AUTHOR]

With increasingly stringent emissions regulations, there are growing demands for the transient performance of diesel engines. This study conducted a transient bench test on a two-stage turbocharged heavy-duty diesel engine to optimize its performance during a load increase (20% to 100% in 1 s) at a constant speed (1200 RPM) transient process. The results showed that the transient control scheme using the low-pressure EGR system resulted in a 42.1% reduction in the peak value of soot emission, a 24.8% decrease in the peak value of NOx emission, a 9.14% decrease in ISFC and a 30.6% increase in maximum IMEP achieved in 1 s, compared to the steady-state optimization control scheme without EGR. Transient control scheme using the high-pressure EGR system resulted in a 24.4% reduction in the peak value of soot emission, a 31.8% reduction in the peak value of NOx emission, a 9.52% reduction in ISFC, and a 31.7% increase in maximum IMEP achieved in 1 s. The comparison of high and low-pressure EGR systems revealed that the low-pressure EGR system produced lower compromising emissions, while alterations in control parameters for the diesel engine with a high-pressure EGR system had a more significant impact on the transient process performance. [ABSTRACT FROM AUTHOR]

In compliance with proposed targets of green energy and reduced emissions during the Glasgow summit, the study of blended fuels in internal combustion engines is of great significance. To address this issue, a detailed study of the engine performance and exhaust emissions has been conducted with ternary fuel blends of diethyl ether (DEE), waste soybean cooking oil (WSCO) biodiesel, and ultra-low sulfur diesel (ULSD). Ternary blends were prepared by adding 0–15% v/v DEE with the B35 blend (35% v/v WSCO biodiesel + 65% v/v ULSD), and tests were carried out with 15% EGR. The RSM based modeling and experimental approaches have been used for analysis. With a desirability of 0.961, the ternary blend DEE10B35EGR15 (10% v/v DEE + 90% v/v B35 at 15% EGR) was found to be an optimal blend. The measured responses are 0.272 kg/kWh, 31.47%, 18.94 HSU%, 91 ppm, 0.030%, and 24 ppm for brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), smoke, nitrogen oxides (NOx), carbon monoxide (CO), and hydrocarbon (HC) emissions, respectively. An innovative approach to analysis and quantifying the responses to ternary blends with EGR has been presented in the form of mathematical equations for future use and scope. [ABSTRACT FROM AUTHOR]

A single cylinder low powered diesel engine of 3.5kW was modified to run on Common rail direct injection high pressure split injection system. This modified engine was tested to run on the neat diesel with ultra-cooled exhaust gas recirculation. The adjustable working parameters i.e., injection pressures 200bar, 230bar, 250bar, 300bar and 350bar, retarded injection -11°, split injection -54°and -11°. After Top dead center position, Exhaust gas recirculation flow rates 5% & 10% respectively are tested on this engine under two typical operating conditions of ? full load of 0.875kW and ? full load of 2.625kW respectively. Single factor and multifactor orthogonal quadratic regression analysis has been carried to determine the effect of these 4 working parameters on engine emissions NOx. The mathematical equations characterizing the relationship between these 4 operating variables are formed. The equation of the NOx and noise was from the orthogonal regressive test under 1/4 Full load and ? Full load conditions was set as the objective function and the ranges of these 4 working variables are given as the constraint condition. Models of non-linear programming were then formulated and solved by using statistical analytical software. Test results showed that 10% Single Injection generates NOx of 194.87 parts per million while 10% Multiple fuel injection generates 199 while the minimum NOx that can be produced is 134.27. [ABSTRACT FROM AUTHOR]

Major energy production all over the world depends on fossil fuels. Recent research on alternative energy sources has raised major concerns about environmental impacts, future availability, and cost. Pollution from diesel engines also affects the environment negatively. As a result, there is a worldwide concern about reducing the pollutants emitted by diesel engines. In comparison to diesel fuel, biodiesel combustion produces reduced carbon monoxide (CO2) and unburned hydrocarbon (UHC) emissions but higher nitrogen oxide (NOx) emissions. The current study aims to investigate the thermal and chemical effects of exhaust gas recirculation (EGR) on the features of a diesel engine for environmental sustainability. The punnai oil was produced from kernels of punnai seeds and transesterified in two phases using alcohol with the existence of a catalyst. The higher viscosity of punnai oil biodiesel is diluted by mixing it with diesel fuel. Our previous investigation indicated that neat punnai oil biodiesel is a potential fuel; however, the findings showed that the addition of diesel is necessary to obtain acceptable engine performance. In this study, punnai oil biodiesel was mixed at a rate of 20% with diesel (B20) and run in a diesel engine with varied EGR rates under five different engine loads. This combined impact enhanced the maximum heat release rate (HRR) and maximum combustion pressure, according to the findings. The premixed burning fractions were commonly higher at all engine loads, whereas the diffusion combustion fractions were lower. When the centre of the HRR changed toward the top dead centre (TDC), combustion durations remained rather constant. The experimental results revealed the B20 blend at a 10% EGR flow rate produced 6.57% lower BTE, 37.04% higher BSEC, 2.47% higher EGT, 5.13% lower CO, 31.11% higher CO2, 3.13% higher UHC, 8.36% lower NOx, and 4% higher smoke opacity when compared with diesel in a standard diesel engine. [ABSTRACT FROM AUTHOR]

The developments in the field of nano-additives have increased in the recent years due to the desire to reduce the level of exhaust emissions in diesel engines. The soot characteristics of particulate matter (PM) and nitrogen oxides (NOX) were experimentally investigated using two concentrations of titanium dioxide (TiO2) as nano-additives (25 ppm and 40 ppm) blended with C20D (composed of 20% castor oil methyl ester and 80% diesel fuel) and 30% exhaust gas recirculation (EGR). The combustion of C20D + TiO2 increases brake thermal efficiency (BTE) by 2.8% in comparison with neat C20D, while a significant reduction was obtained in BSFC 6.5% and NOX emissions were maintained at a level parallel with diesel. The results indicated that the technique involving a high EGR rate and the addition of 25 ppm and 40 ppm of TiO2 nanoparticles to the C20D exhibits better reductions in NOX emissions by 17.34% and 21.83%, respectively, compared to the technique comprising the use of C20D + TiO2 and C20D. The reduction in the total concentration of PM via the addition of TiO2 nanoparticles to the C20D was 26.74% greater than neat C20D and diesel. In contrast, the incorporation of a high rate of EGR with C20D +TiO2 increased the PM concentrations by 16.85% compared to the technique without EGR. Furthermore, the high concentrations of TiO2 nanoparticles (40 ppm) in the C20D produced 19 nm smaller soot nanoparticles compared to the 23 nm larger soot nanoparticles produced from the low concentrations of TiO2 nanoparticles (25 ppm) added into the C20D. The current investigation reveals that the reduction in NOX emissions and the production of soot nanoparticles notably improved due to the synergic effect of EGR, the TiO2 nanoparticles, and biodiesel. [ABSTRACT FROM AUTHOR]

To meet the requirements of increasing stringent emission regulations, innovative solutions are adopted to reduce NOx emissions from diesel engines. In this study, the GT-Power software was utilized to investigate NOx control possibility of Miller cycle in combination with exhaust gas recirculation (EGR) and post-injection in a diesel engine. The results indicate early intake valve closing reduced compression work, resulting in a power increase of 0.3 kW. Furthermore, the cooling effect of Miller cycle lowered maximum temperature by 24.5 K and NOx emissions by 17.4%. Miller cycle and EGR combination was able to lower NOx emissions by 83.7%, although it resulted in higher Soot emissions. Adding post-injection help to mitigate this issue, lowering NOx emissions by over 20% and Soot emissions by 5.8%. Finally, the combination of MD75 + 12% EGR +2.5 mg post-injection mass at 34°CA ATDC achieved a 76.1% reduction in NOx emissions with only a 2.6% impact on brake power using modeFRONTIER for multi-objective optimization. [ABSTRACT FROM AUTHOR]

In this study, the effects of intake port injection of methane and direct of injection diesel on emissions and the combustion of a light-duty RCCI engine were numerically researched. In this way, AVL Boost software was used for 1-dimensional simulation of the combustion process and emission estimation. Higher octane number methane gas was mixed with air from the intake port, while lower octane number diesel fuel was injected directly into the combustion chamber during the compression stroke. Methane gas was injected at a rate of 65% and diesel fuel at a rate of 35%. The diesel injected directly into the combustion chamber was sprayed at a rate of 5% between 0 and 35 °CA with 8 different injection timings after the main injection. In the model engine, 50% high EGR rate was applied in all combustion modes. The results showed that these parameters have significant effects on performance and emissions. The results in summary; NOx emission reduced at all engine speeds with delayed diesel post-injection timing. The maximum drop of NOx emission was 57.34% with Post15. Although the addition of methane slightly increased the soot emission, it was significantly reduced by the simultaneous addition of methane and application of post-injection strategies of diesel fuel. The soot emission was reduced by 58.85% with the Post35 injection strategy. [ABSTRACT FROM AUTHOR]

To meet the requirements of increasing stringent emission regulations, innovative solutions are adopted to reduce NOx emissions from diesel engines. In this study, the GT-Power software was utilized to investigate NOx control possibility of Miller cycle in combination with exhaust gas recirculation (EGR) and post-injection in a diesel engine. The results indicate early intake valve closing reduced compression work, resulting in a power increase of 0.3 kW. Furthermore, the cooling effect of Miller cycle lowered maximum temperature by 24.5 K and NOx emissions by 17.4%. Miller cycle and EGR combination was able to lower NOx emissions by 83.7%, although it resulted in higher Soot emissions. Adding post-injection help to mitigate this issue, lowering NOx emissions by over 20% and Soot emissions by 5.8%. Finally, the combination of MD75 + 12% EGR +2.5 mg post-injection mass at 34°CA ATDC achieved a 76.1% reduction in NOx emissions with only a 2.6% impact on brake power using modeFRONTIER for multi-objective optimization. [ABSTRACT FROM AUTHOR]

Using high charge dilution low temperature combustion (LTC) strategies in a diesel engine offers low emissions of nitrogen oxides (NOx). These strategies are limited to part-load conditions and involve high levels of charge dilution, typically achieved through the use of recirculated exhaust gases (EGR). The slow response of the gas handling system, compared to load demand and fuelling, can lead to conditions where dilution levels are higher or lower than expected, impacting emissions and combustion stability. This article reports on the sensitivity of high-dilution LTC to variations in EGR rate and fuel injection timing. Impacts on engine efficiency, combustion stability and emissions are assessed in a single-cylinder engine and compared to in-cylinder flame temperatures measured using a borescope-based two-colour pyrometer. The work focuses on low-load conditions (300 kPa gross indicated mean effective pressure) and includes an EGR sweep from conventional diesel mode to high-dilution LTC, and sensitivity studies investigating the effects of variations in charge dilution and fuel injection timing at the high-dilution LTC condition. Key findings from the study include that the peak flame temperature decreased from ~2580 K in conventional diesel combustion with no EGR to 1800 K in LTC with low-NOx, low-soot operation and an EGR rate of 57%. Increasing the EGR to 64% reduced flame temperatures to 1400 K but increased total hydrocarbon (THC) and carbon monoxide (CO) emissions by 30–50% and increased fuel consumption by 5–7%. Charge dilution was found to have a stronger effect on the combustion process than the diesel injection timing under these LTC conditions. Advancing fuel injection timings at increasing dilution kept combustion instability below 2.5%. Peak in-cylinder temperatures were maintained in the 2000–2100 K range, while THC and CO emissions were controlled by delaying the onset of bulk quenching. Very early injection (earlier than 24 °CA before top-dead-centre) resulted in spray impingement on the piston crown, resulting in degraded efficiency and higher emissions. The results of this study demonstrate the potential of fuel injection timing modification to accommodate variations in charge dilution rates while maintaining low NOx and PM emissions in a diesel engine using low-temperature combustion strategies at part loads. [ABSTRACT FROM AUTHOR]

Polyoxymethylene dimethyl ether (PODE) is one of the most promising alternative fuels for diesel engines with a high cetane number, high oxygen content, and no C-C bonds. In this paper, a new spray model with a novel cavitation sub-model is adopted in order to create a numerical model suitable for engine simulation fueled with PODE/diesel blends. The effects of the blending ratio, injection timing, and EGR rate on the combustion and emission characteristics are investigated by the simulation. The simulation results show that the self-restoring oxygen properties of PODE can efficiently improve the combustion, causing a higher in-cylinder temperature, and therefore, higher NOx emissions. Additionally, with the increase in the blending ratio, the increase in the oxidation activity of PODE/diesel blends and the improvement of atomization are conducive to reducing soot emissions. Then, the injection timing and EGR rate are optimized. The numerical results suggest that the NOx emissions decrease initially and then increase; however, soot emissions decrease monotonically with the delay of the injection timing. When the volume blending ratio is 15%, the emission performance is best when the injection timing is between 710 °CA and 715 °CA. The increase in EGR rate can effectively reduce the in-cylinder temperature and control the NOx emissions, but the excessive EGR rate leads to higher soot emissions and a deteriorated combustion process. Therefore, an EGR rate in the range of 0.0 to 0.2 has a better comprehensive emission performance from the perspective of controlling both the NOx and soot emissions. [ABSTRACT FROM AUTHOR]

Most research studies have focused on reducing NOx emitted from diesel engines by adding oxygenated fuels (such as alcohol and biodiesel) to diesel to prepare a good alternative to conventional diesel fuels. Biofuels produced from vegetable oil and waste cooking oil while alcohol can be produced from sugarcane and corn. In the current study, the biodiesel used in the tests was derived from waste cooking oil. In this study, the influence of adding Exhaust Gas Recirculation (EGR) to diesel, biodiesel (D80B20), diesel-pentanol (D85PEN15), diesel octanol (D90OCT10), diesel-propanol (D95PRO5) and diesel-biodiesel-pentanol (D50B40PEN10) blends on performance and emitted pollutants of a diesel engine was investigated. The practical experiments were divided into two parts, the first section comparing the results of using diesel and other fuels at different speeds 2100, 2400, 2700 and 3000 rpm at constant loads without EGR. The second section studied the effect of adding EGR in variable proportions (5 %, 10 %, 15 % and 20 %) to the studied fuel mixtures at constant loads and speed. The results showed that adding biodiesel to diesel (without EGR) increases brake specific fuel consumption, NOx and CO2 emissions by 13.66 %, 41.35 % and 30.49 %, respectively, but, the thermal efficiency of the brakes, exhaust gas temperatures, UHC and CO decreases at rates of 12.58 %, 10.22 %, 18.9 % and 21.31 %, respectively, compared to diesel. When EGR was added at 20 %, the maximum increase for D80B20, D95PRO5, ED100, and D85PENT15 was: 18.38 %, 24.60 %, 45.84 %, and 20 %, respectively, compared to when no EGR was added. The thermal efficiency, exhaust gases temperature and NOx levels decreased when EGR rate was raised. [ABSTRACT FROM AUTHOR]

Recently, most of the researchers focused on provide lower greenhouse gas emissions that emitted from diesel engines by using renewable fuels to be good alternative to the conventional diesel fuel. Ethanol can be derived from renewable sources such as sugar cane, corn, timber and dates. In the current study, the ethanol fuel used in the tests was derived from the dates. The effects of using exhaust gas recirculation (EGR) diesel-ethanol blend (E10) with on engine performance and emissions characteristics have been studied in diesel engine under various engine loads. This study focused the use of oxygen in the bio-ethanol composition to compensate for the decrease occurred by the addition of EGR, which improves the engine performance and reduces its emissions. In this experiment, the ratios of EGR were 10%, 20% and 30% as well as 10% ratio of ethanol was blended into the diesel fuel blend under fixed engine speed. A traditional (without additional systems to reduce emissions) four cylinders direct injection (DI) diesel engine was used for all tests. The brake specific fuel consumption (BSFC) increased with increasing the EGR ratio by 10%, 20% and 30% by 18.7%, 22.4% and 37.4%, respectively. The thermal efficiency decreased under variable conditions of engine load for different ethanol blends. Furthermore, the emissions of NOX decreased when fuelled B10 into the engine in comparison with diesel under low engine load. Significant reduction in the NOx emissions were found when applied EGR in the tests than to the absence EGR for E10 blend and diesel. The NOx reduction rate was 12.3%, 30.6% and 43.4% when EGR rate was 10%, 20% and 30%, respectively. In addition, the concentrations of HC and CO emissions decreased more by 8.23% and 6.4%, respectively, when using E10 in comparison with the diesel for various engine loads. It is indicated that the oxygen reduction by EGR effect was compensated from ethanol blend combustion. The results showed that the combination use of E10 and EGR leads to significant reduction in engine emissions accompanied with partial reduction in the engine performance. [ABSTRACT FROM AUTHOR]

This study developed a numerical model for an ammonia/diesel dual direct-injection two-stroke engine and validated it based on engine bench test results. The engine combustion and emission characteristics were discussed under the cases of different injection parameters, intake temperatures, and exhaust gas re-circulation (EGR) rates. The findings indicate that altering the injection angle of ammonia and diesel sprays impacts the in-cylinder swirl and the ignition timing of the ammonia spray, consequently affecting the heat release phase of ammonia combustion. A suitable arrangement spray plumes can effectively reduce the emissions of unburned ammonia and greenhouse gas (GHG), while increase the emissions of NO x. On the other hand, higher intake temperatures can increase the average in-cylinder temperature, reducing unburned ammonia, N 2 O and GHG emissions. However, it also results in greater NO emissions, which can affect fuel economy negatively. Furthermore, the use of EGR technology can reduce the combustion temperature, thereby lowering the emission of nitrogen-based pollutants, but it also reduces ammonia combustion efficiency. By simultaneously applying the three aforementioned technologies within a certain range of conditions, it is possible to effectively synergize and control nitrogenous emissions and GHG while maintaining high thermal efficiency of ammonia/diesel dual direct injection engines. • Utilize experimental and numerical simulation methods to analyze low emission technology in ammonia-diesel engines. • Revealed the effects of spray layout on the combustion and emissions of ammonia-diesel dual direct injection engines. • The influence law of intake temperature on the combustion and emissions of ammonia-diesel engines is reasonably analyzed. • The study evaluated the effects of EGR on NO x and unburned ammonia emissions in ammonia-diesel engines. • By integrating above technologies, synergistic control of nitrogen emissions and GHG in ammonia-diesel engines was achieved. [ABSTRACT FROM AUTHOR]

The N47 engine debuted in March 2007 in the facelifted BMW 1 Series E87 and E81 and was also available in the BMW 1 Series E82 and E88, which were introduced the same year. The N47 engine replaced the M47 engine that had been in production for 8 years. The M47 construction underwent several modifications, so the injection system was changed, the cylinder head now consists of two parts, and the engine block is made of aluminium. Two main versions of the N47 engine are known: N47D16 (1.6 L) and N47D20 (2.0 L). In the case of both versions, several models with different performances were born. After the distribution of BMW passenger cars equipped with the N47D20 engine, it received a lot of negative criticism due to malfunctions. In this article, I would like to present the maintenance of the engine, which can be used to avoid the failure of passenger cars equipped with the N47D20 diesel engine with huge material damage. [ABSTRACT FROM AUTHOR]

Water electrolyzed hydroxyl gas (HHO or Brown gas) and compressed natural gas (CNG) are the important and promising alternatives to the pure fossil fuels. The global concern is about GHG emission in the environment and ambient air pollution steered by mass consumption of fossil fuels in automobile industries and power sectors. In this study, the combustion, performance and emission characteristics of HHO gas and CNG mixtures supplied to intake manifold of compression ignition engine using diesel as a pilot fuel are studied. The same investigations are repeated with various exhaust gas re-circulation (EGR) proportions to study the impact of EGR on multi fuel mode (diesel + HHO gas + CNG) in a Diesel engine. The multi fueled engine performance, combustion and emission parameters are presented and compared with graph and analytical discussion. The results indicated that at full load, the NOx emission decreased by 4% (without EGR), 18% (with 10% EGR) and smoke density decreased by 78% with multi fuel mode comparing to the pure diesel operation at constant speed of 1500 rpm. Also more enhanced performance by improving the brake thermal efficiency by 17%, reducing the brake specific energy consumption by 19%, resulted better fuel economy, and power due to better combustion. [ABSTRACT FROM AUTHOR]

• Emission Reduction: Hydrogen addition reduces CO by up to 83% and soot by 88% at 50% hydrogen content. • Impact of Hydrogen Addition: Increases engine efficiency and reduces CO and soot emissions, but raises NOx emissions. • EGR Effect : 10% EGR effectively reduces NOx emissions but increases CO emissions. This study investigates the impact of hydrogen addition and exhaust gas recirculation on combustion characteristics and emissions in a diesel-hydrogen dual-fuel engine. A 3D CFD model of a heavy-duty diesel engine is utilized under full load and constant speed conditions at 1600 rpm. Hydrogen is introduced into the intake system at varying percentages 0 %, 10 %, 20 %, 30 %, 40 %, and 50 % of total thermal energy, while exhaust gas is utilized at 5 % and 10 % of gas intake volume with 40 % hydrogen. Results show that increasing hydrogen percentage enhances engine efficiency. CO and soot emissions decrease significantly up to 33 % and 88 %, with 50 % H 2 and 40 % H 2 addition respectively, while NO X emissions increase notably by 57 % at 50 % hydrogen. Additionally, utilizing exhaust gas at 10 % intake volume effectively reduces NO X emissions but caused CO to increase. These findings underscore the substantial influence of hydrogen percentage on combustion characteristics and emissions formation, emphasizing the potential for emissions mitigation and improved combustion efficiency in dual-fuel engines. [ABSTRACT FROM AUTHOR]

The Miller cycle has significant advantages of suppressing knocking and improving nitrogen oxide (NO X) emissions without the penalties of reducing engine fuel consumption and power output. In the study, the effect of non-Miller cycle and Miller cycle on the exhaust gas recirculation (EGR) introduction capability and the knocking boundary were evaluated on a stoichiometric combustion natural gas engine at three different loads. Additionally, the effect of Miller cycle coupled EGR and ignition timing on engine performance and combustion process was discussed. The results indicate that, for the same condition, the Miller cycle could reduce peak temperature and pressure, increased combustion duration, and delayed combustion phase, which makes for effective knocking suppression. Therefore, the Miller cycle has less dependence on the EGR strategy to control knock. Moreover, the Miller cycle can also reduce the ability to introduce EGR, which could up to 3.8%. By matching the ignition timing and EGR rate, the BSFC of the Miller cycle were decreased by 0.6g/kW·h, 2.4 g/kW·h and 2.9 g/kW·h respectively for three test conditions compared with non-Miller cycle. In terms of emissions, the Miller cycle and EGR can both suppress NO X emissions, while the EGR being more effective. The study will provide valid information for the application of the Miller cycle to achieve efficiency clean combustion of natural gas engine. • The effect of different cycles on the boundary parameters of the engine is compared. • The effect of the Miller cycle on the combustion process of the engine is investigated. • The potential for optimizing fuel economy and improving NO X emissions of Miller cycle coupled EGR is explored. [ABSTRACT FROM AUTHOR]

Drop-in biofuels can play an important role in the transition from fossil-based fuels to carbon-neutral energy carriers. This work focuses on performance and emission of hydrotreated pyrolysis oil (HPO) for heavy-duty (HD) engines application. The HPO is blended with marine gas oil (MGO) in various mass ratios and tested both in combustion research unit (CRU) and engine facilities. Typical cruise speeds and multiple loads are selected in the heavy-duty engine tests. Both inlet temperature and EGR rate are varied to investigate the effects of control parameters on HPO. The results reveal that HPO present lower reactivity than MGO and diesel under CRU condition. It can function as a drop-in fuel without any modification to the engine and no recalibration was required. Specifically, key combustion phases are noticed to be identical. The engine can run smoothly and safely at 50% blend ratio with 1% reduction on net indicated efficiency (NIE) and 0.002 g/kWh particulate matter emissions (PM). At low load, the NOx emissions decrease to 1 g/kWh at 40% EGR, yet 1% decrease of NIE is shown. While all fuels yield more NOx but less PM emissions as the increase of inlet temperature. Inlet heating does decrease the NIE by 1%. • Engine can be fueled with 50% hydrotreated pyrolysis oil blends safely. • Soot/NOx emission tradeoff is noticed for hydrotreated pyrolysis oil blends. • Hydrotreated pyrolysis oil yields less indicated efficiency than commercial fuels. • Inlet heating barely influences combustion and decreases 1% net indicated efficiency. • At 40% EGR, 1 g/kWh ISNOx is achieved while keeping ISPM below 0.1 g/kWh. [ABSTRACT FROM AUTHOR]

Dilution and Miller cycle are effective ways to reduce fuel consumption. Based in a 4-cylinder, 4-stroke, turbocharged, low pressure EGR, in-cylinder direct injection gasoline engine, with two intake camshaft angle (133 °CA, 170 °CA), the effects of dilution (lean combustion, EGR) and Miller cycle on combustion and fuel economy at the minimum fuel consumption (2750 rpm, 11 bar) were studied. Besides, 1D engine simulation and 3D flow simulation are used to study the difference of combustion modes. When COVimep is less than 3 %, the BSFC of EGR is lower than that of lean combustion at the same dilution rate. The dilution limit of lean combustion is larger than EGR. When the dilution rates of EGR and lean combustion are 22 % and 35.9 %, respectively, the BSFC reaches the minimum, which decreases by 4.7 % and 7.2 % respectively. The specific heats ratio of lean combustion is larger than EGR, so the theoretical thermal efficiency of lean combustion is higher. Miller cycle reduces intake time and intake valve lift, which result in the tumble ratio and turbulent kinetic energy decrease significantly. EGR has greater fuel-saving potential for Otto cycle engine than Miller cycle. [ABSTRACT FROM AUTHOR]

Palm oil is one of the most common and productive vegetable oils, so it is often used as an excellent feedstock for biodiesel production. However, due to the high viscosity and other issues of palm oil, it cannot be directly used as an alternative fuel for diesel engines unless some treatment is carried out. In this study, the effects of palm oil-diesel blend fuel on the nitrogen oxides (NOx)–smoke trade-off characteristics were investigated in a common rail direct injection (CRDI) diesel engine under various injection pressures and exhaust gas recirculation (EGR) rates. It was found that NOx and smoke from the combustion of fuel containing 50% palm oil (P50D50) were simultaneously suppressed by 3% and 3.1% compared with diesel fuel at an injection pressure of 400 bar, respectively. The performance of P50D50 was comparable to that of diesel, but at high injection pressure and high EGR rate, it showed shorter ignition delay (ID) and lower smoke emission. [ABSTRACT FROM AUTHOR]

In reactivity-controlled compression ignition (RCCI) engines, the ignition and combustion of premixed low reactive fuel (LRF) such as natural gas (NG) is controlled by the injection of high reactive fuel (HRF) such as diesel fuel during the compression stroke. In this study, the effects of six different input parameters on the performance and emissions of the natural gas/diesel fueled RCCI engine are studied using fractional factorial design (FFD) method, which is one of the design of experiment (DOE) methods. In this method, the effects of the interactions of input parameters, referred to as "factors," on the outputs, referred to as "responses," are investigated. The factors include premixed ratio (PR), start of first injection (SOI1), spray angle (SA), exhaust gas recirculation (EGR), start of second injection (SOI2), and mass fraction of first injection. Sixteen runs were conducted to evaluate the effects of the interaction between input factors on performance and emissions of a RCCI engine using a validated computational fluid dynamics (CFD) model. DOE results indicate that in order to increase gross indicated efficiency (GIE), higher premixed ratio, 85%, with wider spray angle, 150°, is an effective way. Meanwhile, carbon monoxide (CO) and unburned hydrocarbons (UHC) emissions as well as ringing intensity (RI) are decreased at this condition. To reduce NOx emissions, it is beneficial to raise premixed ratio from 55% to 85% or to use 40% EGR, independently. [ABSTRACT FROM AUTHOR]

Biofuels are the most promising alternative to petro-diesel. In this work, the combined effect of mahua biodiesel and 1-Hexanol is studied on the engine characteristics. The concentration of both 1-Hexanol and mahua biodiesel is varied, 10%, 20%, and 30% each with diesel fuel. Common rail direct injection diesel engine is used in this study. Engine load is varied from 20% to 80% in step of 20%, the speed of the engine is constant throughout the experiment. Biofuel blends showed improved cylinder pressure and mean gas temperature at a higher engine load. At 60% load, 10H10M80D (10% 1-Hexanol/10% mahua biodiesel/80% diesel) showed 3.45% lower thermal efficiency and 6.11% higher fuel consumption compared to diesel. At 60% load, all the biofuel blends showed 50% lower carbon monoxide emission. At 60% load, 10H10M80D showed 33.33% lower hydrocarbon emission and 0.96% higher nitrogen oxide emission compared to baseline readings. The biofuel blends are less sensitive to exhaust gas recirculation (EGR) due to the oxygenated nature of biofuels. With 20% EGR, at 60% load, 10H10M80D showed 39.48% lower nitrogen oxide compared to no EGR. The results of 10H10M80D showed the best performance at all loads. [ABSTRACT FROM AUTHOR]

Exhaust gas recirculation (EGR) is a type of mature technology used to reduce NOx emissions from diesel engines. However, the use of EGR causes diesel engines to produce more particulates. In this paper, the particulates of diesel, diesel/biodiesel blend (50% biodiesel) and biodiesel were collected and measured at different EGR rates. High-resolution transmission electron microscopy (TEM) and thermogravimetric (TG) analyses were used to study the effects of EGR on the microstructure, composition and oxidation characteristics of particulates. The results showed that with the increase of biodiesel content in the diesel/biodiesel blend, the accumulation of diesel/biodiesel particulates was denser, the particle size of particulates for the diesel/biodiesel blend was smaller, the soluble organic fractions (SOF) content in particulates was increased and the surface activation energy of the particulates was reduced. With the increase of the EGR rate, the boundary of multiple particulate overlap areas was difficult to distinguish, the particle size of the particulates increased, and the SOF content in the particulates increased, while the soot content decreased gradually. When the EGR rate was increased from 0% to 15% and 30%, the activation energy of particulates for biodiesel was decreased by 15.59% and 26.63%, respectively. [ABSTRACT FROM AUTHOR]

This research work evaluates the influence of compression ratio and exhaust gas recirculation on combustion, performance, and emission characteristics of a compression ignition engine powered with diesel/WLDPE oil/1-decanol. A ternary blend was prepared using splash blending technique and the blend ratio was designated as 70% volume of diesel + 20% by volume of WLDPE oil + 10% by volume of 1-decanol called as D70L20DEC10 blend. The experimental trials were carried at three compression ratios (16:1, 17.5:1, and 19:1) and three EGR rates (0%, 10%, and 20%) at the maximum power output of the engine. Results indicated that ignition delay period get shortened as the compression ratio got higher. The in-cylinder pressure and the rate of heat release dropped with escalating EGR rates and increased with the higher compression ratio. In comparison with CR 17.5:1 and CR 16:1, BTE increased by 4% and 6%, respectively, for CR 19:1 operation. CR 19:1 under 0% EGR rate gave diesel equivalent BTE. The NOx emission escalated with increasing CR and reduced upon increasing the EGR rates. At CR 19:1, NOx emission was reduced by 58.82% as EGR grows from 0 to 20%. When compared to CR 17.5:1 and CR 16:1 smoke emission got suppressed by 31.6% and 36%, respectively, with CR 19:1 under 0% EGR operation. On the other hand, smoke emission aggravated with higher EGR rates at all CR. Both HC and CO emission decrease with higher CR and increased with the inclusion of EGR. Finally, CR 19:1 and 10% EGR rate are suggested as the best operating parameters when the engine is fueled with the ternary blend. [ABSTRACT FROM AUTHOR]

Recently, there is an increasing interest in the pyrolysis of waste plastic into usable fuel as a friendly environment method for waste plastic disposal. The existing literature from various studies stated that the major problem related to the use of WPO in diesel engines is the high NOx emissions level. This paper aims to remedy this problem by suggesting the best EGR percentage with the advanced optimum injection timing. Primary, 5 EGR percentage fractions are considered: 0%, 5%, 15%, 20% and 25% percent. The results showed that 25% is the best percentage regarding emissions. However, a significant reduction in mean in-cylinder pressure, temperature, and heat release rate was depicted with the EGR fraction increase. Injection timing is advanced to recoup the decrease in performance. The results showed that 25% of EGR and advanced injection timing by 5 degrees would be better for performances and emissions of DI diesel engine while running with waste plastic oil as an alternative fuel. [ABSTRACT FROM AUTHOR]

In this research work, four different diesel injection schedules have been experimented at a BMEP of 2 bar (Low load) in hydrogen diesel dual fuel (HDDF) mode, which are namely single pulse, double pulse phase-1, double pulse phase-2 and multi-pulse. The maximum possible hydrogen energy shares (HES) for single pulse, double pulse phase-1, double pulse phase-2 and multi-pulse injection schedules were 73.99%, 48.98%, 34.46% and 24.39% respectively. Over the injection schedules, double pulse phase-2 improved the brake thermal efficiency (BTE) from 19.50% (single pulse) to 21.61% with a penalty in NO emission. On the other hand, multi-pulse moderately increased the BTE with significant reduction in NO beside rise in smoke emission. At a BMEP of 5 bar (Medium load) operation, there was a considerable reduction in NO emission at maximum range of HES level with 18.21% of EGR, moreover the engine stability was improved with minor increase in smoke emission. Image 1 • Injection schedule and EGR influence the hydrogen diesel dual fuel (HDDF) mode. • Double pulse phase-2 enhance the performance of HDDF mode with penalty in NO. • Multi-pulse moderately increases the performance with significant reduction in NO. • Optimum level of EGR at high hydrogen energy share decreases the NO without smoke. [ABSTRACT FROM AUTHOR]

This paper analyzes the emissions of a single‐cylinder diesel engine fueled with biodiesel, using selective catalytic reduction (SCR) and exhaust gas recirculation (EGR) techniques. The aim of this paper is to compare both EGR and SCR techniques, which were studied under different brake powers. Grape seed biodiesel was used as a test fuel. Experiments were performed by both techniques at different loads and rates to find out the performance change in the engine and the change in the emission rates using both the techniques. Then the observations from both the techniques were compared, concluding that both the techniques show a sufficient reduction in NOx. Using the abovementioned techniques, a reduction in hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOx), and smoke was observed. The EGR technique is more suitable for low‐load engine vehicles, as it affects the efficiency of the engine with an increase in the fuel consumption, whereas the SCR technique is suitable for high‐load engines, which do not affect the efficiency of the engine with a decrease in the fuel consumption. [ABSTRACT FROM AUTHOR]

The development of HCCI combustion technology has been drawing a great deal of attention from researchers. This survey explains ongoing research methodologies and results. HCCI combustion, other than conventional combustion, is purely based on chemical kinetics. At present the automobile sector faces the problem of emissions and needs to develop clean technologies. However, HCCI operation still has issues such as ignition control, combustion phasing control, operating range control, cold start, and UHC (unburned hydrocarbon) and CO (carbon monoxide) emissions. The challenge is to overcome these problems without compromising other engine parameters and performance. For HCCI, the mixture preparation is especially important, while the compression ratio, IVC (inlet valve closure) timing, inlet pressure, inlet temperature and EGR play a very prominent role in controlling it. This paper will go through a detailed discussion of all the above conditions. [ABSTRACT FROM AUTHOR]

The transient pressure waves in the intake and exhaust systems directly affect the intake and exhaust processes of diesel engines, thus further affecting the combustion process and the performance of diesel engines. The variation rules of the intake and exhaust pressure waves at different engine speeds and loads in a high-pressure common-rail diesel engine were studied. Then, the effects of EGR rate and VNT nozzle opening on the intake and exhaust pressure waves were systematically studied by bench test and one-dimensional simulation analysis. The results show that at 2000 r·min-1 full-load, when the EGR rate increases from 0 to 10%, the average intake pressure and the average exhaust pressure both decrease. The fluctuation waveforms of the intake pressure and the exhaust pressure change significantly. The fluctuation intensity of the intake pressure decreases by 58.6%, and the fluctuation intensity of the exhaust pressure increases by 77.2%. As the EGR rate increases from 10% to 30%, the average intake pressure and the average exhaust pressure both decrease. The fluctuation waveforms are basically unchanged. The increasing magnitudes of the intake and exhaust pressure fluctuation intensities are 16.6% and 20.5%, respectively. As the VNT nozzle opening increases, the average intake pressure and the average exhaust pressure both decrease. The corresponding phases of the intake pressure wave crest and trough are delayed. The fluctuation waveforms of the intake and exhaust pressure are basically unchanged, and the fluctuation intensities do not change significantly. [ABSTRACT FROM AUTHOR]

Biodiesel is an alternative sustainable energy source and can be utilized in the compression ignition engine without any changes in the engine design. This research work focuses on the preparation of Calophyllum inophyllum methyl ester through two steps of transesterification process and its implementation in common rail direct injection diesel engines under various fuel injection strategies. At the initial stage of the current research work, two biodiesel blends of 10 vol% and 20 vol% with remaining quantity as diesel have been used as fuel in a diesel engine at a fuel injection pressure of 600 bar at 5%, 10% and 15% pilot injection variations. In the second stage, the study has been extended for the same strategies of injecting the fuel at the rates of 10% and 20% exhaust gas recirculation. All the experimental results are compared with diesel fuel at an injection pressure of 600 bar with 10% pilot injection. The experimental results revealed that an increase in the blend ratio of biodiesel enhances the combustion, performance characteristics and proliferation of pilot injection from 5 to 15% facilitates spontaneous and complete combustion. It is observed that 15% pilot injection quantity of 20 vol% Calophyllum inophyllum methyl ester blend has shown the best performance among the test samples with other injection strategies. The results also showed that the implementation of exhaust gas recirculation at 10% and 20% rates during diesel engine operation is evident in lower performance characteristics with a significant impact on oxides of nitrogen and carbon dioxide emissions. [ABSTRACT FROM AUTHOR]

In the present work, dual fuel operation of a diesel engine has been experimentally investigated using biodiesel and hydrogen as the test fuels. Jatropha Curcas biodiesel is used as the pilot fuel, which is directly injected in the combustion chamber using conventional diesel injector. The main fuel (hydrogen) is injected in the intake manifold using a hydrogen injector and electronic control unit. In dual fuel mode, engine operations are studied at varying engine loads at the maximum pilot fuel substitution conditions. The engine performance parameters such as maximum pilot fuel substitution, brake thermal efficiency and brake specific energy consumption are investigated. On emission side, oxides of nitrogen, hydrocarbon, carbon monoxide and smoke emissions are analysed. Based on the results, it is found that biodiesel-hydrogen dual fuel engine could utilize up to 80.7% and 24.5% hydrogen (by energy share) at low and high loads respectively along with improved brake thermal efficiency. Furthermore, hydrocarbon, carbon monoxide and smoke emissions are significantly reduced compared to single fuel diesel engine operation. Exhaust gas recirculation (EGR) has also been studied with biodiesel-hydrogen dual fuel engine operations. It is found that EGR could improve the utilization of hydrogen in dual fuel engine, especially at the high loads. The effect of EGR is also found to reduce high nitrogen oxide emissions from the dual fuel engine and brake thermal efficiency is not significantly affected. • Biodiesel-H 2 dual fuel operation of the diesel engine has been experimentally studied. • Performance features with maximum pilot fuel substitution and emissions are analysed. • Biodiesel showed better pilot fuel substitution at low load and low emission. • It was possible to significantly reduce NO x emissions at high load using EGR. [ABSTRACT FROM AUTHOR]

Experimental study of 1-pentanol addition and EGR rates on the combustion, performance and emission of a CRDI diesel engine is carried out in this work. 1-Pentanol being a higher alcohol has fuel properties comparable to diesel. Experiments were conducted on a 4 stroke two cylinder, CRDI diesel engine running at a constant speed of 2000 rpm for lower load and higher load. Test fuels were prepared by blending the 1-pentanol with diesel, and tests were carried out for 5%, 10%, 20%, 30% and 40%, 1-pentanol blended in diesel on a volume basis. Effect of EGR rates of 10% and 20% were also studied. It had observed that engine can be run up to 30% of 1-pentanol blended fuel without any engine modification, but with raise in the percentage of 1-pentanol in the blends, BSFC increases and BTE decreases. Combustion characteristic for blended fuel depends upon the load. At higher load due to premixed combustion MGT, CP and NHR were almost same compared to the diesel. Reduction in NO x emissions was noted for all the fuel blends at the cost of HC and CO emission. 1-pentanol is a renewable biofuel, with use of 1-pentanol the dependency on petrodiesel can be overcome. • 1-pentanol is a promising alternative to the diesel fuel. • 1-pentanol blends reduce the CP, MGT and NHR at lower load and increases at higher load due to the premixed combustion. • 1-pentanol blends and EGR reduce the BTE and increase the BSFC. • Ignition delay period is increased for all the 1-pentanol blends due to low cetane number and EGR rate. • 1-pentanol blends and EGR significantly reduces the NO x emission. [ABSTRACT FROM AUTHOR]

The influence of rail pressure control on fuel consumption, emissions and combustion in an automotive downsized turbocharged diesel engine was investigated, considering different operating modes in three-part load working conditions. These modes were selected according to the results of a previous step of the study, where low NOX and fuel consumption levels were obtained managing a hybrid exhaust gas recirculation (EGR) system and the turbocharger variable nozzle turbine (VNT). Aiming at limiting observed soot penalties, increased values of rail pressure were applied, deepening the interactions with engine-controlled sub-assemblies and the related variations in operating, environmental, energy and combustion parameters. At low levels of engine speed and load, major reduction in NOX emissions and fuel consumption were observed, with acceptable soot and noise combustion increase, while turbocharger speed was also enhanced. No variations in fuel consumption were achieved at higher load and speed, while soot penalty remained significant. A simplified method to describe and model engine behaviour and combustion process was also developed, defining linear relationships between rail pressure and engine quantities, including a wide set of combustion parameters derived from in-cylinder pressure diagrams and heat release curves. [ABSTRACT FROM AUTHOR]

Dimethyl ether (DME) and n-pentanol can be derived from non-food based biomass feedstock without unsettling food supplies and thus attract increasing attention as promising alternative fuels, yet some of their unique fuel properties different from diesel may significantly affect engine operation and thus limit their direct usage in diesel engines. In this study, the influence of n-pentanol, DME and diesel blends on the combustion performance and emission characteristics of a diesel engine under low-temperature combustion (LTC) mode was evaluated at various engine loads (0.2–0.8 MPa BMEP) and two Exhaust Gas Recirculation (EGR) levels (15% and 30%). Three test blends were prepared by adding different proportions of DME and n-pentanol in baseline diesel and termed as D85DM15, D65P35, and D60DM20P20 respectively. The results showed that particulate matter (PM) mass and size-resolved PM number concentration were lower for D85DM15 and D65P35 and the least for D60DM20P20 compared with neat diesel. D60DM20P20 turned out to generate the lowest NO x emissions among the test blends at high engine load, and it further reduced by approximately 56% and 32% at low and medium loads respectively. It was found that the combination of medium EGR (15%) level and D60DM20P20 blend could generate the lowest NO x and PM emissions among the tested oxygenated blends with a slight decrease in engine performance. THC and CO emissions were higher for oxygenated blends than baseline diesel and the addition of EGR further exacerbated these gaseous emissions. This study demonstrated a great potential of n-pentanol, DME and diesel (D60DM20P20) blend in compression ignition engines with optimum combustion and emission characteristics under low temperature combustion mode, yet long term durability and commercial viability have not been considered. • Suitability of n-pentanol/DME/diesel blends in a LTC diesel engine was examined. • LTC mode was enabled by utilizing moderate EGR level and alcohol/diesel blends. • Engine performance drops slightly by blending oxygenated fuels and EGR induction. • PM/NOx trade-off can be control with suitable oxygenated blends fuel in LTC mode. [ABSTRACT FROM AUTHOR]

• A split injection strategy is helpful to reduce the risk of wetting the cylinder walls for very advanced injection timings. • Combination of EIVC and EGR for very advanced injection can reduce NO x emissions in part load CI engine operation. • In PCCI combustion mode, a combined EIVC - heavy EGR strategy significantly increases soot and CO emissions. • In the EIVC strategy, combustion efficiency decreases by 4% and 8%, respectively, for 0% and 70% EGR rates. • For any EGR rate, the ISFC of the engine operating in an EIVC strategy is higher than that of the base IVC case. Premixed Charge Compression Ignition (PCCI) combustion is an alternative to conventional diffusion-controlled combustion for Mono-nitrogen oxides (NO x) and soot emissions reduction in DI diesel engines. However, bringing the center of combustion (CoC) near top dead center (TDC) to reduce brake specific fuel consumption is challenging. In this study, for two Early Intake Valve Closing (EIVC) profiles of split injection strategy, combustion characteristics and emissions of a heavy-duty direct injection (HDDI) diesel engine are evaluated by CFD simulations. Combustion efficiency, Indicated Specific Fuel Consumption (ISFC), NO x , soot, and carbon monoxide (CO) emissions are evaluated for 40 ˚CA and 80˚CA EIVC timings with respect to the base diesel combustion with 0, 30, 50, and 70% Exhaust Gas Recirculation (EGR) rates at 3 bar Brake Mean Effective Pressure (BMEP). CFD simulations reveal that EIVC strategy can displace the CoC towards TDC up to 5–10 ˚CA depending on the EGR rate. Moreover, up to 30% NO x reduction can be achieved in EIVC cases. In 70% EGR case, lower ISFC and near zero NO x emissions can be obtained compared to conventional diesel combustion due to CoC being closer to TDC. However, the EIVC strategy with EGR increases CO emissions due to incomplete combustion of a lower air/fuel ratio mixture. [ABSTRACT FROM AUTHOR]

Pressure difference across the exhaust and intake manifolds (Δ P) is a crucial variable to control the pumping loss and cylinder charge dilution through the exhaust gas recirculation in a diesel engine. This paper presents a novel architecture for controlling Δ P and the engine-out NO x emissions, which increases the controller tolerance to engine components aging. The architecture has an internal control loop, designed as a two-input two-output controller, to coordinate the exhaust gas recirculation and variable geometry turbine valves. Using feedback from Δ P and the estimated cylinder oxygen ratio χ cyl , the two-input two-output controller regulates the pumping loss and the engine NO x emissions. To reduce high turbo lag and its associated slow air–fuel ratio (λ) response, which are inherent features of a Δ P -based control strategy, the two-input two-output linear quadratic controller is tuned such that λ is also regulated, but only during fast transients. An external loop is supplementing the core two-input two-output controller correcting the internal loop set points to reduce the effects of χ cyl estimation errors on NO x control and ensure λ stays above a minimum value, λ min , critical for smoke emissions. As a feature of the proposed control system, direct feedback from Δ P increases pumping loss robustness to common degradation in diesel engines, namely, turbine efficiency and diesel particulate filter blockage due to ash deposit, compared to a conventional boost pressure–based controller. Also, it is shown that the input–output coupling structure of the proposed two-input two-output controller and use of the NO x feedback mitigate effects of exhaust gas recirculation fouling and associated exhaust gas recirculation valve saturation on increase in NO x emission. [ABSTRACT FROM AUTHOR]

In this work, the development and usability of kapok oil in diesel engine was intended. With this purpose, the piston crowns are coated with mullite–lanthanum (ML) ceramic composite at varying compositions in order to reduce the heat rejection during combustion process. The kapok oil is blended with diesel fuel consisting of (20% kapok oil–80% diesel) volumetrically named B fuel. The B and diesel (D) fuels are taken for the engine performance test with different coated piston (ML1, ML2, and ML3) and exhaust gas recirculation (EGR—10%, 20%, and 30%), compression ratio (CR—16, 17, and 18) and engine load (50%, 75%, and 100%). Also, the engine performance study on brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), hydrocarbons (HCs), oxides of nitrogen (NOx), carbon monoxide (CO), smoke opacity, and numerical study using ANSYS software is carried out. When operated with ML2-coated pistons with B fuel, maximum BTE value of 29.2%, minimum BSFC value of 0.224 kg/kW-h, CO emission of 0.2%, and smoke opacity of 39 ppm were observed. The results showed that ML2-coated piston considerably improved the performance of the test engines when compared with ML1 and ML3 coatings. Except for NOx emission, all other pollutant emission values were reduced. The numerical analysis using ANSYS software for ML2-coated pistons showed better retention of in-cylinder chamber temperature. [ABSTRACT FROM AUTHOR]

Abstract This study investigates the performance, combustion and emission characteristics of diesel (D)/straight vegetable oil (SVO)/diethyl ether (DEE) blend in a variable compression ratio engine (VCR), variable engine speed direct injection compression ignition (CI) engine. The compression ratio (CR), speed (N), and load (L) were taken as input factors for the diesel engine optimization. This investigation is done through a combination of experimental data analysis and artificial neural network (ANN) modeling. The response surface methodology (RSM) optimization concerned to minimize the engine emissions and maximize the engine performance. Three optimization works were conducted for 65% D+25% SVO+10% DEE blend, in optimization-1 (opti-1) considered 0% exhaust gas recirculation (EGR), Opti-2 considered 5% EGR and Opti-3 considered 10% EGR. Compared to diesel, carbon monoxide (CO), oxides of nitrogen (NOx), and hydrocarbon (HC) were reduced by 12.8%, 4.19% and 9.61% respectively for blend fuel in opti-2. Highlights • To study effects of engine load, speed and compression ratio on engine behavior. • A ternary blend of chaulmoogra seed oil, neat diesel and diethyl ether used as fuel. • Exhaust gas recirculation varied 5% and 10% on volumetric basis. • Artificial neural network based prediction and RSM based optimization analysis. • Maximum brake thermal efficiency of 29.3% was obtained in no EGR mode. [ABSTRACT FROM AUTHOR]

Abstract The constant escalation in the consumption of petroleum products has compelled researchers to discover for new alternative fuels which can be successfully incorporated in the existing automotive engines. Oil derived from waste plastics is one such alternative, which not only ensures longevity of fossil fuels but also assists in bringing down the hazardous impacts caused by the improper disposal of plastic wastes. This work focuses on the utilization of valuable energy of toxic non-biodegradable waste plastics to lucratively be used as an alternative fuel. An attempt was further made to reduce the NO X emissions which increased with the use of waste plastic oil blend. The main objective of this experimental investigation is to study the performance & emission characteristics of a twin cylinder CRDI engine subjected to selective catalytic reduction (SCR) after-treatment technique. Different flow rates of ammonia as a reducing agent were tested and concluded that a flow rate of 0.5 kg/hr furnishes optimum results. A comparison of NO X reduction efficiency was also made between SCR and EGR techniques. The comparison eventually indicated that SCR gives better NO X conversion efficiency at higher loads without any adverse effect on the engine performance while operating on Waste Plastic Oil blend (P30). Highlights • Performance, combustion and emission characteristic of waste plastic oil blend is investigated. • Rhodium/ceramic catalyst is found to be very active in the medium temperature range of 240°C-280°C. • SCR technique is observed to give getter NOx conversion efficiency at higher loads in comparison to EGR. • 0.5 kg/hr ammonia flow rate furnished optimum results. [ABSTRACT FROM AUTHOR]

With the increment in global demand for energy, there is a need to reduce vehicle emission, which is among the major causes of air pollution around the world. In order to reduce the emissions levels, this study focuses on the effects of hot exhaust gas recirculation (EGR) system on the performance and emissions of a direct injection (DI) diesel engine. The performance studied includes engine power, torque, brake mean effective pressure, fuel consumption and the exhaust emission. The engine used in this study was a single-cylinder, four-stroke engine with an air-cooled system at a rated speed of 3600 rpm with displacement of 0.219 litres. The engine was operated at varying speeds of 1600 to 3600 rpm with different percentages of EGR (5%, 7%, 10% and 15%). Based on the results, it was shown that EGR had decreased the engine brake power and torque while increasing fuel consumption at the same time. The engine with EGR has reduced the emission level of NOx from 800 to 240 ppm and CO2, from 9% to 4%, while increasing the CO from 2% to 4% and UHC from 10 to 100 ppm. Hence, it was concluded that low emission level of NOx and CO2 could be obtained using EGR as it can be used to improve the emission level of a homogeneous charge compression ignition (HCCI) even further in the extension of this study. [ABSTRACT FROM AUTHOR]

Research on alternative fuel production and compression ignition (CI) engine improvement techniques is more attractive recently. Waste-to-wealth concept refers that the utilization of the waste of soapberry seed and exhaust gas to run the common rail direct fuel injection type diesel engine by optimizing their contribution through experimental analysis is the novelty of this investigation. The recirculation of exhaust gas plays important role in improving the combustion in the engine, reducing the emissions, and improving the engine performance. Soapberry seed oil methyl ester economizes diesel consumption by mixing it into diesel. Transesterification is the method used to turn soapberry seed oil into biodiesel. In the common rail direct injection (CRDI) engine, a 10%, 20%, or 30% blend of soapberry seed oil methyl ester (SSOB) with diesel is utilized as fuel. For each mix, 10%–30% of the volume of SSOB is added to the rest of the diesel. Along with these fuel types, exhaust gas recirculation (EGR) is used from 10% to 30% to test and optimize the best combinations for CRDI engines. The experimental results show that pure diesel with EGR recorded high heat release rate (HRR) and brake thermal efficiency (BTE) at the highest load possible. The maximum BTE of the tested tracks is 26.83% because of better combustion, which was achieved with 10% EGR and a combination of 30% SSOB and 70% Diesel. The increase in EGR such as 30% in 30% of SSOB with 70% of Diesel blend produced reduced NOx emission (865 ppm), smoke opacity (13%), and hydrocarbon (HC) emissions (10 ppm) than diesel fuel because of the dilution and chemical effects during combustion. Accordingly, the present research reveals that a 30% of soapberry seed oil methyl ester blend with 30% EGR is recommended for engine usage with lesser emission with better combustion and performance characteristics. • Soapberry seed oil was converted into soapberry methyl ester via transesterification method. • Engine was fuelled with 10%, 20%, and 30% blend of soapberry seed oil methyl ester (SSOB) with conventional diesel fuel. • Exhaust gas recirculation (EGR) is used from 10% to 30% during the experiments. • Detailed combustion, performance, and emission characteristics of CRDI engine are discussed. [ABSTRACT FROM AUTHOR]