Impact Of Injection Pressure Research Articles

Impact of injection pressure on a dual-fuel engine using acetylene gas and microalgae blends of chlorella protothecoides

The amount of fossil fuel usage in compression ignition (CI) engines is greatly reduced when biodiesel is used. The primary disadvantage of using biodiesel is that, due to its high viscosity, which causes fuels to remain unburned during the premixed combustion stage, leads to lower brake thermal efficiency (BTE). Gaseous fuels predominantly reducing emissions in CI engines due to its complete burning without leaving any carbon traces. Fuel injection pressure (FIP) is one of the factors which is influencing the combustion phase because they are used to optimize fuel particle atomization. The current study examines engine parameters for a dual fuel engine that runs on biodiesel blends made from 20 % methyl ester of chlorella protothecoides micro algae (B20MEOA) and acetylene gas under variable Fuel injection pressure (FIP) ranging from 200 bar to 240 bar with 10-bar steps. According to the experimental results, when 3 LPM of acetylene gas is supplied along with the intake air and B20MEOA supplied at a FIP of 240 bar, the emissions such as smoke opacity, hydrocarbon (HC), and carbon monoxide (CO) are reduced by 16.9 %, 8.3 %, and 15.4 %, respectively, whereas the oxides of nitrogen (NOx) increases by approximately 7 % when compared to B20MEOA alone operation.

Impact of injection pressure on the performance, emissions, and combustion of a common rail direct injection engine fueled with quaternary blends

The scarcity and rising costs of fossil fuels, coupled with increasing pollution levels, have prompted the exploration of innovative biofuel blends. While binary and ternary fuels have been studied extensively in proportions of 5–20%, replacing up to 30–40% of fossil fuel dependency without significant engine modifications remains a challenge. One potential solution is to investigate an optimal quaternary blend (QB) through experimental methods. This study investigates the impact of increased injection pressure (IOP) and quaternary fuel blends on a common rail direct injection (CRDI) engine's performance and emissions. Different blends, including diesel fuel, vegetable oil, mahua methyl ester and normal-butanol, were tested to replace 30–40% of diesel and enhance combustion, reduce exhaust emissions and improve overall performance. Experiments used a 1-cylinder CRDI engine at high IOPs (400, 500, 600 and 700 bar). Results at 600 bar IOP showed that the optimal blend, QB3–QB4, increased brake thermal efficiency (BTE) by 9% and reduced brake-specific fuel consumption (BSFC) by approximately 11% compared to other blends. Emissions at 600 bar included a 16% reduction in hydrocarbons (HC) and a 24% decrease in carbon monoxide (CO) at full load. However, nitrogen oxide (NOx) emissions slightly increased with higher IOP. Significantly employing the QB3–QB4 blend at 600 bar improved control over HC, CO and smoke emissions. Overall, performance was enhanced and comparable to conventional diesel fuel, with only a minor increase in NOx emissions.

Impact of injection pressure and polyaxial stress on hydraulic fracture propagation and permeability evolution in graywacke: Insights from discrete element models of a laboratory test

Understanding the hydromechanical behavior and permeability stress sensitivity of hydraulic fractures is fundamental for geotechnical applications associated with fluid injection. This paper presents a three-dimensional (3D) benchmark model of a laboratory experiment on graywacke to examine the dynamic hydraulic fracturing process under a polyaxial stress state. In the numerical model, injection pressures after breakdown (postbreakdown) are varied to study the impact on fracture growth. The fluid pressure front and crack front are identified in the numerical model to analyze the dynamic relationship between fluid diffusion and fracture propagation. Following the hydraulic fracturing test, the polyaxial stresses are rotated to investigate the influence of the stress field rotation on the fracture slip behavior and permeability. The results show that fracture propagation guides fluid diffusion under a high postbreakdown injection pressure. The crack front runs ahead of the fluid pressure front. Under a low postbreakdown injection pressure, the fluid pressure front gradually reaches the crack front, and fluid diffusion is the main driving factor of fracture propagation. Under polyaxial stress conditions, fluid injection not only opens tensile fractures but also induces hydroshearing. When the polyaxial stress is rotated, the fracture slip direction of a fully extended fracture is consistent with the shear stress direction. The fracture slip direction of a partly extended fracture is influenced by the increase in shear stress. Normal stress affects the permeability evolution by changing the average mechanical aperture. Shear stress can induce shearing and sliding on the fracture plane, thereby increasing permeability.

Non-monotonic change of ignition delay with injection pressure under low ambient temperature for the diesel spray combustion

The impact of injection pressure on the startability of compression ignition (CI) diesel engines has not been thoroughly studied yet, especially for the startup at low-temperature conditions. This research investigates the effects of injection pressure on diesel spray and flame characteristics under low ambient temperatures (close to the critical ignition temperature of diesel spray) in a constant volume combustion chamber (CVCC) using Schlieren, Mie scattering, and direct photography. Different from past engine startability research, the ignition delay time under quasi-critical ignition temperature is measured to be first shortened then prolonged with increasing injection pressure. The primary cause of such phenomenon is analyzed to be the trade-off effects between spray atomization and heat convection from the fuel to the ambience, which is quantitatively validated by the analytical calculation based on the Arrhenius-type correlation.

Numerical study on turbulent dispersion of diesel sprays under ultrahigh injection pressure using large eddy simulation

ABSTRACT The modern diesel engines equipped with an advanced fuel injection system up to ultrahigh injection pressure of 300 MPa are under development at present. The impact of injection pressure on fuel spray characteristics such as spray penetration and spray cone angle has been widely concerned in previous studies. However, it is still lack of the detailed investigation on the turbulent dispersion of small droplets produced by a high-pressure injector due to the limited capability of optical diagnostic techniques to simultaneously measure the two phases. Droplet dispersion due to turbulence plays a major role in high-velocity fuel spray mixing and combustion processes involving group evaporation of droplets. Thus, the effect of different injection pressures on droplet dispersion in nonevaporating diesel sprays was investigated using the Euler-Lagrange framework with large eddy simulation (LES) implemented in an open-source code OpenFOAM. Size-dependent instantaneous radial motion and dispersion characteristics of droplets dominated by large-scale turbulent structures within a polydisperse downstream spray were analyzed in detail. Results show that increasing injection pressure can modestly promote the radial dispersion of most droplets with diameter of 2 ~ 12 µm further downstream at the late stage of injection. This could be the result of the increasing interaction time of droplets with larger turbulent structures due to the increase of spray penetration with increasing injection pressure. However, increasing injection pressure has no significant impact on the strength of droplet-turbulence interaction in terms of slip velocity between droplet and gas phases and this could be quantitatively explained by the droplet Stokes number (St) estimated in this study. The most droplets with 0.1 < St < 10 tend to move and concentrate further radially outward, leading to droplet clustering. Thus, the effect of injection pressure on droplet-turbulence interaction is much less than its influence on droplet size for high-velocity fuel sprays, indicating that the ultrahigh injection pressure has much less important impact on the spatial inhomogeneity of droplet distribution than its influence on the evaporation rate of individual droplets.

An Experimental Assessment on the Impact of Injection Pressure on the Characteristics of a Diesel Engine Powered with the Blend of Diesel and Microalgae Biodiesel

Microalgae was recognized as the sustainable energy feedstock for producing biofuels. Now bio-diesel produced from algal biomass is getting ready to address the energy crisis that the world would face tomorrow. This paper deals with the utilization of microalgae biodiesel at 30% blend, to investigate the influence of operating parameter such as injection pressure on the characteristics of a compression ignition engine. Microalgae crude oil was derived from chlorella vulgaries and it was converted into microalgae methyl ester (MME) using transesterification process. The desired test fuel was prepared by mixing of 30% MME with 70% pure diesel and designated as B30. The experiment was conducted on single cylinder four stroke diesel engine powered with B30 at various fuel injection pressures in the range of 180 bar, 200 bar and 220 bar. The experimental results showed that, no significant impact of modified injection pressures on BSFC, whereas BTE was increased maximum by 14.09% at 200 bar. The exhaust emissions such as CO, CO2, UHC and smoke opacity were improved mostly at 200 bar injection pressure, but NOX emission was increased, and increment in cylinder peak pressure was discovered only at 200 bar.

Impact of injection pressure on CO2–enhanced coalbed methane recovery considering mass transfer between coal fracture and matrix

Although the production mechanism of CO2-enhanced coalbed methane (ECBM) recovery has been previously reported and corresponding models have been proposed, investigations on the effect of the injection pressure on the production efficiency considering the mass transfer between the coal fracture and matrix are lacking. In this study, laboratory core flooding experiments were conducted on the coal sample from South Sichuan Basin, China. Experimental results indicate that earlier breakthroughs and a higher initial CH4 flow rate and cumulative CH4 flow rate occurred under a higher injection pressure in the CO2-ECBM recovery. However, as CO2 was continuously injected, the CH4 flow rate and cumulative CH4 flow rate under a lower injection pressure exceeded those at the higher injection pressure. Furthermore, a dual porosity model was used to perform numerical simulations. The simulation results under four injection pressures matched the experimental results well. The simulation results indicate that the dispersion in fractures and the mass transfer rate between matrices and fractures significantly affect the CH4 flow rate. The injection pressure leads to changes in the experimental observations by affecting the dispersion and the mass transfer rate.

Impact of injection pressure on the performance and emission characteristics of a diesel engine fuelled with Annona methyl ester

This work investigates the influence of injection pressure (IP) on the performance and emission characteristics of single cylinder direct injection (DI) diesel engine using (20%, 40%, 60%, 80% and 100%) Annona methyl ester (AME) blended diesel fuel. The performance parameters such as brake specific fuel consumption (BSFC), brake thermal efficiency (BTE) and exhaust gas temperature (EGT) tests were carried out at different IPs (180 bar, 200 bar, 220 bar and 240 bar) at different loads. Emissions levels of HC, CO, smoke and NOx were compared with the diesel fuel. It was found that, at IP 240 bar for A20 blended fuel (20% AME + 80% diesel) shows better performance and lower emission levels which is very close to neat diesel fuel. At this optimized pressure, the BTE is smaller than neat diesel fuel and provides a reduction in carbon monoxide, unburned hydrocarbon and smoke emissions with an increase of oxides of nitrogen emission when compared to that of neat diesel fuel. It is found that an increase of IP increases the BTE and lowers exhaust emissions without any major engine modification.

Simulation study on spray combustion mechanism of diesel–gasoline blend fuels

In order to reveal the spray combustion mechanism of blend fuels, a combustion model was established using EDC model based on previous experimental research. The simulation results show that under lower co-flow temperature, the auto-ignition of n-heptane (represent diesel) occurred earlier than gasoline (represent gasoline), as a result of the combined effect of slower vaporization rate and lower activation energy required for the initial dehydrogenation reaction. On the contrary, under high co-flow temperature condition, iso-octane began to ignite before n-heptane, because the chemical reaction of both n-heptane and iso-octane occurs rapidly due to the rapider vaporization so that the auto-ignition delay is most determined by the vaporization and diffusion rate of fuel. The simultaneous auto-ignition temperature “Ts” was defined in previous work to represent the co-flow temperature, at which diesel and gasoline ignited spontaneously. Further simulation research results show that, the increment of injection pressure and background pressure will increase Ts, and the impact of injection pressure on Ts is much less than that of background pressure.

Modeling the Ignitability of a Pilot Injection for a Diesel Primary Reference Fuel: Impact of Injection Pressure, Ambient Temperature and Injected Mass

In this paper, we studied the accuracy of computational modeling of the ignition of a pilot injection in the Sandia National Laboratories (SNL) light-duty optical engine facility, using the physical properties of a cetane/iso-cetane Diesel Primary Reference Fuel (DPRF) mixture and the reaction kinetics of a well-validated mechanism for primary reference fuels. Local fuel-air equivalence ratio measurements from fuel tracer based planar laser-induced fluorescence (PLIF) experiments were used to compare the mixture formation predictions with KIVA-ERC-based simulations. The effects of variations in injection mass from 1 mg to 4 mg, in-cylinder swirl ratio, and near-TDC temperatures on non-combusting mixture preparation were analyzed, to assess the accuracy of the model in capturing average jet behavior, despite its inability to model the nonnegligible jet-by-jet variations seen in the experiments. Fired simulations were able to capture well the measured ignitability trends at the different injection conditions tested, but showed some deviations in the minimum temperature needed for robust ignition, pointing out the need for further work to focus on achieving fully comprehensive modeling with detailed chemical kinetics of the DPRF58 mixture and a full engine geometry representation.

Performance Analysis of C I Engine with Dual Fuel Mode for different Speeds.

Rapid depletion of conventional energy sources, along with increasing demand for energy is a matter of serious concern for the mankind. The factor that petroleum based fuels will neither be available in sufficient quantities nor at a reasonable price in future, has revived interest in exploring the use of alternative fuels. It is essential that these alternative fuels for engine should be drive from indigenous sources and preferable renewable energy sources. In this work, experiments are conducted by governing pilot fuel and speed for defined loads. in the present work, the engine performance characteristics are computed using CNG as the main fuel and diesel as the pilot fuel of dual fuel mode. From the experimental investigations, it is concluded that the engine performance of the dual fuel operation is better than the diesel fuel operation. I. Introduction: India's energy needs are growing with economic development and growing population. The indigenous energy resources may not be sufficient in the long run to sustain the process of economic development of 9% of Gross Domestic Product. The country's energy supply system continues to be dependent on fossil fuels, which are finite. The oil and gas share in the energy consumption has reached a level of about 45% and is expected to remain so. Globally also the share of oil is expected to remain at the same level in future also. The industrial growth of any country is measured by the amount of energy generation as well as its consumption. The fuel-air mixture before combustion and the burned products after combustion are the actual working fluids. The work transfers which provide the desired power output occur directly between these working fluids and the mechanical components of the engine. Because of their simplicity, ruggedness and high power-to-weight ratio, the Internal Combustion engines have found wide range of applications in agriculture, transportation and power sectors. The strategy to implement alternative fuels in Internal Combustion engines is becoming the subject of interest nowadays. The reasons are driven by the energy independence from petroleum based fuel (2). Among the alternative fuels, CNG has been recognized as one of the promising alternative fuel due to its substantial benefits compared to gasoline and diesel (4). However, the number of Vehicles powered by this alternative fuel is still small compared to the number of conventional vehicles that powered by gasoline and diesel. In the case of gaseous engine, from 5.5 millions - only one million used CNG and the rest used LPG (1). The main objectives of this project is to study the effects of using CNG as an alternative fuel as a replacement for diesel in compression ignition engines. In the present work, diesel is used as the pilot fuel to ignite CNG and CNG as the main fuel. The impact of injection pressure is to be observed at constant and variable loads with different engine speeds to study the engine performance characteristics. In the present work, comparison analysis is to be carried out with diesel and dual fuel operation.