Effects Of EGR Research Articles

Assessing the influence of EGR on diesel pilot ignition combustion with methane/hydrogen blends in a single-cylinder compression ignition engine

This paper experimentally investigates the impact of EGR on the combustion performance and emissions of methane/hydrogen blends for the diesel pilot ignition (DPI) combustion strategy. Different speed/load cases were evaluated on a single-cylinder compression ignition engine for hydrogen energy shares ranging from 0% to 20%. As hydrogen was added to the premixed mixture, the combustion phasing (CA50) was held constant by either adjusting the pilot start of injection (SOI) timing or using EGR at constant intake pressure (varying premixed equivalence ratio). The experimental results show that the use of EGR at constant intake pressure with methane/hydrogen blends leads to lower unburned hydrocarbon (UHC), carbon-monoxide (CO), and nitric oxide (NO) emissions when compared to the methane-only baseline. Adiabatic flame temperature calculations were used to help explain the observed engine out nitric oxides (NOx) emissions trends. The UHC emissions, however, were significantly higher than the baseline split-injection diesel case due to incomplete combustion and crevice effects. Combustion efficiency improved without a thermal efficiency reduction with hydrogen addition, suggesting that substitution with hydrogen can be beneficial for dual-fuel compression ignition strategies that utilize natural gas. The decay rate for CH4 and H2 was more than linear, which is attributed to the chemical effects of hydrogen addition and EGR.

Experimental study on the optimization of operating conditions for hybrid powertrain gasoline engines

With the rapid expansion of the market for hybrid vehicles, the development of dedicated hybrid powertrain engines has become an important research direction. This study focuses on the techniques to improve the fuel economy of dedicated hybrid powertrain operating conditions of 2000 rpm, 110 Nm. Turbocharging can enhance the performance and fuel economy of gasoline engines while reducing emissions. However, intake boosting increases the pressure and temperature of the mixture in the cylinder at the compression end timing, leading to a higher risk of knock, which is not conducive to the safety and fuel consumption reduction of gasoline engines. Low-temperature combustion with mixture dilution can effectively reduce the occurrence of knock and NOx emissions. In this study, the effects of EGR and VVT strategies as different dilution methods on the combustion of turbocharged gasoline engines were investigated. The experimental results indicate that both EGR and VVT can achieve mixture dilution in the cylinder, reducing the combustion temperature and thus lowering NOx emissions. Furthermore, advancing the ignition timing results in CA50 trending towards the optimal fuel consumption point, shortening the combustion duration CA10–90, and reducing ISFC. Compared to VVT, EGR can better suppress knock, leading to an earlier ignition phase CA50, a shorter combustion duration, and ultimately less fuel consumption. The research findings provide technical support for the optimization of dedicated hybrid powertrain operating conditions.

Effect of multiple injection optimization on combustion characteristics of low-pressure EGR system engine

Abstract In recent years, reducing oil consumption and pollutant discharge in transportation industry has become an important measure to alleviate energy crisis and environmental pollution. Therefore, the fuel economy and emission characteristics of the engine have become an important index to evaluate the quality of an engine, so EGR technology has gradually become the standard of gasoline engines. But EGR is not always good. In order to alleviate the adverse effects of EGR on combustion, further research on engine combustion is needed. In order to study the effect of multiple injection strategy on engine combustion characteristics, this paper takes a high pressure direct injection gasoline engine equipped with low pressure EGR system as the research object, and verifies the designed multiple injection strategy on special test equipment. A large amount of combustion data of the engine under the same load, different fuel injection stages and fuel injection ratios were collected. By comparing the evaluation indexes of main pollutant emission, fuel consumption and combustion stability, it is found that with the increase of injection times, the combustion characteristics and knock of the engine show a trend of improvement. After using multiple injection strategies at 2000r/min, it can be seen that the optimized injection strategy has better emission characteristics and lower fuel consumption lower knock intensity than that before the injection mode optimization without affecting the power performance.

The Impact of Early Growth Response 1 (Egr1) on Hippocampal Synaptic Plasticity and Cognitive Function: Narrative Review

Introduction: EGR1 (Early Growth Response 1) gene expression is a molecular response that occurs in the brain as a result of synaptic activity and environmental stimuli. Early growth response 1 (EGR1) expression can be affected by several factors, including exercise or physical training. This review aims to determine the effect of EGR 1 expression on hippocampal synaptic plasticity function. Method: Literature search using data-based Pubmed, Science Direct, and Scopus online. The data used is from the year 1978 until the year 2022. Searched using English keywords such as EGR 1 and hippocampus. Results: Animal and human studies show that physical exercise can increase the expression of the EGR1 gene in the brain. This enhanced EGR1 expression is associated with increased synaptic plasticity, which includes changes in the strength and connectivity of synapses between neurons. Synaptic plasticity refers to the ability of the nervous system to change the strength and efficiency of communication between neurons. Physical exercise has been shown to increase synaptic plasticity by increasing dendritic growth and continuity, increasing neurogenesis (the formation of new neurons), and increasing synaptic connections between neurons. Physical exercise can increase EGR1 expression and synaptic plasticity. Increased EGR1 expression and synaptic plasticity induced by physical exercise are associated with improvements in cognitive functions, including memory, learning, and thinking ability. Conclusion: There is evidence that exercise can increase EGR1 expression and synaptic plasticity in the brain, especially in the hippocampus, to improve cognitive function.

Investigations on the effects of injection parameters and EGR in a glow plug assisted methanol fueled Hot Surface Ignition (HSI) Engine

Methanol can be produced from renewable sources and is also clean burning. Hence it is an ideal alternative fuel for transportation applications. However, its low cetane number prevents its direct application in compression ignition (CI) engines. One of the promising but not widely explored methods is to use a hot surface for its ignition in CI engines at normal compression ratios. In this work a turbocharged automotive common rail diesel engine was modified to operate in the hot surface ignition (HSI) mode with methanol as the sole fuel with 3% by mass of lubricity and corrosion inhibiting additive. Initially, a single pulse injection (SPI) strategy was employed at different injection timings at a BMEP of 8 bar. Subsequently a double pulse injection (DPI) strategy was employed and the effects of gap between the injection pulses, injection timing and injection pulse width share among the two pulses were studied. The HSI mode of neat methanol performed with comparable brake thermal efficiency (BTE), reduced combustion rates and hence low NOx emission levels with respect to diesel operation when the DPI mode was employed with almost equal pulse width share. Engine performance was better at rail pressures of around 800 bar. Hot EGR of up to 8% was beneficial as it reduced the engine-out NOx without affecting the BTE. The engine was operated at different BMEPs in the range of 4–10 bar and compared with the baseline diesel operation. The BTE was similar to the baseline diesel engine at all loads. Engine-out NOx was lower than diesel operation by 23.6%–61.5% while near zero smoke levels and similar CO and THC emissions (after the DOC) were observed. Though slipped methanol and formaldehyde were the significant unregulated emissions, they were reduced to very low levels after the DOC.

Current Progress and Development Trend of Gas Injection to Enhance Gas Recovery in Gas Reservoirs

Conventional recovery enhancement techniques are aimed at reducing the abandonment pressure, but there is an upper limit for recovery enhancement due to the energy limitation of reservoirs. Gas injection for energy supplementation has become an effective way to enhance gas recovery by reducing hydrocarbon saturation in gas reservoirs. This review systematically investigates progress in gas injection for enhanced gas recovery in three aspects: experiments, numerical simulations and field examples. It summarizes and analyzes the current research results on gas injection for EGR and explores further prospects for future research. The research results show the following: (1) Based on the differences in the physical properties of CO2, N2 and natural gas, effective cushion gas can be formed in bottom reservoirs after gas injection to achieve the effects of pressurization, energy replenishment and gravity differentiation water resistance. However, further experimental evaluation is needed for the degree of increase in penetration ability. (2) It is more beneficial to inject N2 before CO2 or the mixture of N2 and CO2 in terms of EGR effect and cost. (3) According to numerical simulation studies, water drive and condensate gas reservoirs exhibit significant recovery effects, while CO2-EGR in depleted gas reservoirs is more advantageous for burial and storage; current numerical simulations only focus on mobility mass and saturation changes and lack a mixed-phase percolation model, which leads to insufficient analysis of injection strategies and a lack of distinction among different gas extraction effects. Therefore, a mixed-phase-driven percolation model that can characterize the fluid flow path is worth studying in depth. (4) The De Wijk and Budafa Szinfelleti projects have shown that gas injection into water drive and depleted reservoirs has a large advantage for EGR, as it can enhance recovery by more than 10%. More experiments, simulation studies and demonstration projects are needed to promote the development of gas injection technology for enhanced recovery in the future.

Numerical studies on the flow characteristic of the marine two-stroke engine integrated with the high-pressure exhaust gas recirculation system

The high-pressure exhaust gas recirculation (HP-EGR) has been well-proven for marine engines complying with the IMO Tier Ⅲ NOx regulation. Considering different turbocharged scavenging schemes and emission control modes, intake and exhaust gas management is critical to the HP-EGR design. However, few theoretical studies on it were reported. This paper aims at providing a case study on the flow characteristic of the turbocharged HP-EGR system. With the proposed topology structure of the typical HP-EGR layout, numerical studies on the turbocharged scavenging and EGR design were conducted based on the 6EX340 two-stroke engine. The result showed that the flow characteristic of the turbocharged two-stroke engine can be graphically depicted by simplifying the cylinder and turbine as multi-nozzle in series. According to the nozzle flow equation of uniflow scavenging, there exists an optimum turbine flow area to maximize the scavenging mass flow. Effects of EGR, cylinder bypass, and exhaust gas bypass on the flow characteristic of the two-stroke engine depend on the turbocharger matching. The out-cylinder scavenging and in-cylinder combustion should be optimized interactively to fully explore the fuel economy and NOx trade-off. Finally, the proposed design procedure can provide good guidance for the design and control of the HP-EGR system.

The Effects of EGR and Oxygen Content on the GCI Engine Performance Under Two-Injection Modes and Fueled Biodiesel Blends

The Effects of EGR and Oxygen Content on the GCI Engine Performance Under Two-Injection Modes and Fueled Biodiesel Blends

운항 중 EGR이 2행정 사이클 디젤 엔진의 성능에 미치는 영향

운항 중 EGR이 2행정 사이클 디젤 엔진의 성능에 미치는 영향

Experimental investigation of hydrogen combustion in a single cylinder PFI engine

The simultaneous reduction of Green-House Gases (GHG) and criteria pollutants is the main target of current Internal Combustion Engines (ICE) development. Hydrogen (H2) fueling is one of the best options available in both regards, as it does not emit tailpipe CO2 as well as significantly abates all criteria pollutants already at engine-out level. However, optimizing hydrogen combustion in order to exploit the fuel proprieties at best is a challenging task due to the very particular properties of the fuel. In fact, H2 combustion in ICE promotes a very clean, fast and complete combustion process, with extremely low HC, CO, and PM engine-out emissions stemming only from lubricant oil. The usage of lean-boosted and EGR-diluted combustion strategies can significantly contribute to raise the brake thermal efficiency and lower the NOx emission to extremely low levels. To this end, the Authors tested a 0.5 L single cylinder engine featuring an optimized PFI layout and dedicated piston bowl profile for a retrofitted Diesel operating as H2 monofuel, in SI mode. In this paper, the authors discuss the effect of the main engine parameters, extensively investigated by means of Design of Experiments (DoE) techniques, as well as the effect of dilution and EGR to promote clean and efficient hydrogen combustion, in order to recommend the most effective practices.

Effect of EGR on performance and emissions of a methanol–diesel reactivity controlled compression ignition (RCCI) engine

Effect of EGR on performance and emissions of a methanol–diesel reactivity controlled compression ignition (RCCI) engine

Impact of Combined Effects of Injection Pressure and EGR on Modified Stationary Engine Fuelled with Biodiesel Blend Made of Waste Feedstock Oils

Impact of Combined Effects of Injection Pressure and EGR on Modified Stationary Engine Fuelled with Biodiesel Blend Made of Waste Feedstock Oils

Studying the effects of manifold pressure boosting and EGR on combustion and NOx emission of hydrogen-fueled SI engine

Aiming to the global energy insecurity due to extensive dependence on fossil fuels, hydrogen is supposed to provide relief by researchers. However, employed to combustion engines, this green fuel leaves hazardous NOx and limits output due to low volumetric energy content. Hence, improving operating parameters like compression ratio and manifold pressure, and NOx mitigating technique like EGR may prove a boon. Therefore, in the present study, combustion and NOx emission behavior of the SI-engine is studied under variable manifold air pressure (MAP) (up to 130 kPa) and EGR (up to 15%) at compression ratio 14:1. The outcomes shows the flame development increased by 1.24%, while flame propagation is increased by 1.63% by MAP boosting due to increased air and fuel supply. Cylinder pressure and heat-release rate (HRR) are also surged due to the increased fuel supply to maintain excess-air ratio (λ). However, peak cylinder pressure is retarded due to elongated combustion. The exhaust gas temperature (EGT) is increased by 19.4%, while elevated Tmax is observed to shoot up NOx by 40%. Combustion in improved at low EGR due to reduced λ, and also the specific NOx. At higher EGR rate deteriorated combustion due to increased heterogeneity by high dilution, increasing combustion duration, cooling losses and reducing cylinder pressure, Tmax and EGT. A 9.33% and 5.67% increase in CA10 and CA10–90 respectively is observed for 130 kPa at 15% EGR than no EGR. The rapid reduction in oxygen and higher heterogeneity reducing residence time, resulted in rapid drop (33% at N/A to 42.68% at 130 kPa for 15% EGR) in NOx by EGR. The coefficient variation is reduced by boosting MAP but increased severely at higher EGR, which restricts operating EGR rate.

Hierarchical evolutionary construction of neural network models for an Atkinson cycle engine with double injection strategy based on the PSO-Nadam algorithm

There is a strong nonlinear relationship between the input and output of the Atkinson cycle engine (ACE), and with the development of artificial intelligence, fitting this nonlinear relationship with the neural network (NN) has become increasingly popular. In this paper, a lot of research has been conducted on constructing a more accurate NN model for ACE. Firstly, an ACE bench test is conducted, and the correlation analysis and dimensionality reduction of 14 parameters are performed by Pearson correlation coefficient (PCC), and five parameters, BSFC, CO2, CO, NOx and PN, are selected to investigate the effects of different injection strategies and EGR on the combustion, thermodynamics and emission performance of ACE. Secondly, the construction of the NN model of ACE is expressed as an optimization problem with constraints. Finally, a hierarchical evolutionary algorithm named PSO-Nadam is proposed, and the NN model built based on rules-of-thumb methods and the NN model built based on the PSO-Nadam algorithm are compared. The results show that there is a strong nonlinear relationship between BSFC, CO2, CO, NOx and PN with the injection strategy and EGR, and the PSO-Nadam-based NN model is better than the rules-of-thumb-based NN model in terms of both prediction performance and generalization ability in fitting this nonlinear relationship. It is worth mentioning that the rules-of-thumb-based model is overfitted in the prediction of BSFC, while the MSE of the PSO-Nadam-based model are reduced by 13.1%, 0.2%, 91.4%, 42.1% and the R2 are improved by 3.9%, 0.05%, 6.5%, 44.0% in the prediction of CO2, CO, NOx, and PN.

The effect of EGR and hydrogen addition to natural gas on performance and exhaust emissions in a diesel engine by AVL fire multi-domain simulation, GPR model, and multi-objective genetic algorithm

In this study, the effect of adding hydrogen to natural gas and EGR ratio was conducted on a diesel engine to investigate the engine performance and exhaust gases by AVL Fire multi-domain simulation software.For this investigation, a mixture of hydrogen fuel and natural gas replaced diesel fuel. The percentage of hydrogen in blend fuel changed from 0% to 40%. The compression ratio converted from 17:1 to 15:1. The EGR ratios were in three steps of 5%, 10%, and 15%, with different engine speeds from 1000 to 1800 RPM. The Gaussian process regression (GPR) was developed to model engine performance and exhaust emissions. The optimal values of EGR and the percentage of hydrogen in the blend of HCNG were extracted using a multi-objective genetic algorithm (MOGA).The results showed that by increasing EGR, thermal efficiency, the engine power, and specific fuel consumption decreased due to prolongation of combustion length while cumulative heat release increased but, its effect on cylinder pressure is insignificant. Adding hydrogen to natural gas increased the combustion temperature and, consequently NOx. While the amount of CO and HC decreased. The results of GPR and MOGA illustrated that at different engine speeds, the optimum values of EGR and HCNG were 6.35% and 31%, respectively.

A Comprehensive Study on the Effect of Dimethyl Carbonate Oxygenate and EGR on Emission Reduction, Combustion Analysis, and Performance Enhancement of a CRDI Diesel Engine Using a Blend of Diesel and Prosopis juliflora Biodiesel

This paper examines the combined effects of ignition improvers (DMC) and EGR on the CRDI small single-cylinder diesel engine’s performance, combustion, and emissions. In this experimentation, 20% (B20) optimal mix of Prosopis juliflora oil biodiesel (PJOB) and 5 ml dimethyl carbonate (DMC) additive was used as test fuel. The fuel handling CRDI system factors such as injection pressure set at 600 bar and injection timing set to 21 (bTDC) with a compression ratio of 16 were considered for the study. For the EGR trial, 20% of the exhaust gas was recirculated under various BMEP circumstances. The test was performed with and without EGR and DMC additive conditions like (i) diesel @ 0% EGR, (ii) diesel + 5 ml DMC @ 20% EGR, (iii) B20 @ 0% EGR, and (iv) B20 + 5 ml DMC @ 20% EGR at the engine power output. The amalgamation of dimethyl carbonate (DMC) additives and EGR reduces NOx and smoke while increasing CO and HC emissions. In addition, the DMC additive and EGR improve thermal efficiency slightly. The overall clubbing of DMC additive and EGR rate indicates better performance for the selected factors than a CRDI engine with a six-hole conventional mechanical fuel injection system. The outcome of the work clearly demonstrates that both the 5 ml DMC additive and the 20% EGR rate of the B20 blend show optimum values of BTE, BSFC, and EGT of 32.93%, 0.27 kg/kw·hr, and 310.89°C, which is closer to diesel. Factors of combustion like cylinder peak pressure (CPP) and heat release rate (HRR) are 70.93 bar and 58.13 J/deg. The tailpipe exhaust of NOx and smoke is 1681 ppm and 31.30 (% vol), which is less than diesel. The HC and CO levels are 93 ppm and 0.38 (% vol), respectively, which are significantly higher than diesel fuel.

Application of delay embedding and recurrence analysis to a noisy nonlinear map for cyclic combustion dynamics of SI engines

A noisy nonlinear dynamical (NND) model available for cyclic variations in SI engines is examined using nonlinear time series methods. Heat release time series computed from this model is analyzed by employing bifurcation diagrams, return maps, recurrence plots, and recurrence quantitative analysis techniques. The analysis methodology is at first applied to a noisy Logistic map to optimize the necessary parameters, and later the same is used for the NND map. The presence of noise hides the local patterns of the dynamics and higher periodic orbits, making the bifurcation diagrams look fuzzy for both maps. An increase in the noise level and uncombusted residuals in the NND map advance the onset point of bifurcations toward a higher equivalence ratio. The application of the NND model is extended to represent the SI engine combustion dynamics for a higher amount of internal EGR as it is favored for cycle-resolved control due to its feedback period of one combustion cycle. The combined effect of lean charge and internal EGR leads to a more complex dynamical nature. The addition of a higher amount of internal EGR adds some complex chaotic-like regions in the bifurcation diagrams. For a low level of fluctuations in the NND map, more than four noisy periodic orbits are observed for such operating conditions. The geometry of phase space trajectories for the low-level noisy model data with a high level of internal EGR resembles a chaotic system. Bifurcation diagrams, recurrence plots, and quantitative recurrence analysis indicate an intermittent route to chaos at a highly lean and diluted charge. The presence of deterministic chaotic characteristics in combustion dynamics, along with effort-saving techniques of data acquisition and estimating combustion phasing, depicts the possibilities of practical application in active onboard control of engine systems.

Combined Effect of CNG and EGR on the Performance, Emission and Combustion Characteristics of Diesel Engine in Dual Fuel mode

Severe and adverse energy crises in future, day by day ever elevating cost of fuels, dangerous emissions emitted with conventional fuels made internal combustion engine scientists to discover and look at the likelihood of usage of alternate, clean and less or zero emissions fluids and vaporous fuels for IC engines, especially compression ignition diesel engines (DE) since existing DE are under stringent pollutions regulation that too for smoke and NOx in their tail pipe fumes. The main target of this work is to examine the emission, combustion and performance attributes of a diesel engine running with a wide range of loads with a constant speed of 1500rpm with a 30% steedy energy share of CNG and varying EGR of 5%,10% and 15% using diesel as pilot fuel. BSEC of dual fuel mode engine is discovered superior to neat diesel engine mode at higher load. It is discovered that there is an uncommon decrease in NOX, CO2, and smoke density, increment in UHC, CO in the fumes of dual fuel engine at all loads. Comparative results are given for dual fuel mode with variable measures of EGR at various loads conditions and detailed the impact of the application of EGR on combustion, performance and emission processes.

Towards improved performance and lower exhaust emissions using exhaust gas recirculation coupled compression ignition engine fuelled with nanofuel blends

ABSTRACT Emission standards are becoming increasingly stringent. When it comes to diesel engine exhaust emissions, nitrogen oxides (NOx) and soot emissions need effective control as these emissions have a trade-off connection, making it difficult to achieve the emission regulation. To effectively manage NOx emissions from diesel engines, external exhaust gas recirculation has been implemented. The effects of EGR on the engine characteristics of a single-cylinder diesel engine running on pongamia methyl ester mixed with aluminum oxide nanoparticles are detailed in this work. The pongamia methyl ester was mixed with mineral diesel (25 vol. %). The nanofuel blend was made by mixing aluminum oxide nanoparticles with B25 fuel at a dosage of 100 ppm (B25A100). Experiments with diesel, B25, and B25A100 with various EGR rates were conducted in a compression ignition engine (10–30%). The combined impact of nanoparticles blended B25 with 20% EGR yielded a substantial reduction in NOx by 4.95% compared to B25. In addition, the unburnt hydrocarbon, carbon monoxide, and smoke emissions were found to increase as compared with B25. Arise in brake thermal efficiency of 4.6% was noticed for B25A100 + 20% EGR than that of B25. The brake specific fuel consumption was reduced by 4.23% for B25 blend. With 20% EGR, the in-cylinder pressure and instantaneous heat release rate were reduced. As a result, combining pongamia methyl ester with aluminum oxide nanoparticles and 20% EGR enhances engine performance while reducing emissions.

Effects of EGR, injection retardation and ethanol addition on combustion, performance and emissions of a DI diesel engine fueled with canola biodiesel/diesel fuel blend

Biodiesel fuels have been used in diesel engines at different ratios without modifications in the engines. However, the biodiesel fuels generally generate higher NOx emissions than those of the diesel fuel and the related investigations on the higher NOx problem are still ongoing. In this study, three moderation techniques namely exhaust gas recirculation, injection retardation and ethanol addition were comparatively addressed for B10 biodiesel blend (10% canola biodiesel and 90% diesel fuel in vol.). The experimental results revealed that the exhaust gas recirculation of 5% is a suitable method in improving the combustion parameters of B10 biodiesel blend, while the retarded injection timing of 2 CA° is the most effective method regarding both the performance and emission parameters. No favorable effect of 2% ethanol addition to B10 biodiesel blend at retarded injection timing was observed on the performance, and coefficient of variation of indicated mean effective pressure was increased by over 10%. However, all methods examined in this study have effective potentials in the decrease of NOx emissions of the diesel engine running with the B10 biodiesel blend.