Experimental and numerical investigation of multihole Gasoline direct injection (GDI) sprays at high injection pressure and temperature are performed. The primary objective of this study is to analyse the role of gas entrainment and spray plume interactions on the global spray parameters like spray tip penetration, spray angles and atomization. Three-hole 90° spray cone angle and six-hole 60° spray cone angle injectors are used for current work to examine the effect of the geometry of the injector on the spray interactions. The numerical results from Reynolds Average Navier Stokes (RANS) simulations show a reasonable comparison to experiments. The simulations provide further insight to the gas entrainment process highlights the fact that a stagnation plane is formed inside the spray cone which basically governs the semi collapse of spray that in turn affects the spray direction and cone angle.

In this research, a 3D-CFD model was created to investigate the behavior of spray and combustion in a three-cylinder GDI engine using a six-hole nozzle injector. To validate the model, in-cylinder data pressure was conducted at Iran Khodro Power Train Company (IPCO) under wide-open throttle and 5500 rpm conditions. The obtained data were incorporated into the CFD model to simulate the spray evolution and combustion process inside the cylinder during fuel injection. Droplet temperature and lambda distribution from 30 deg to 279 deg after injection Were displayed. Temperature distribution during 2 to 40 deg ATDC was illustrated in the paper. Finally, evaporated fuel and wall film of the cylinder head, liner, and piston. Intake and exhaust valves and equivalence ratio in the combustion chamber have been studied.

Numerical modeling of internal nozzle flow can be regarded as an essential investigation in the field of Gasoline direct injection system of combustion engines since it is directly connected with fuel spray atomization and subsequently efficiency of exhaust gas emission. Internal nozzle flow can be changed and formed according to several parameters such as; system pressure, chosen fuel type, the orientation of spray holes according to injector axis, conicity of spray holes and distribution of spray holes on valve-seat, etc. The changes in these parameters also affect the formation of cavitation inside of whole domain, spray angle and create wall-wetting on the spray hole surfaces. The present work investigates the parameter and design analysis in the valve-seat region of direct Gasoline injection (GDI) injector using Computational Fluid Dynamics (CFD) and Design of Experiments (DOE). CFD is employed to study the behaviors of internal flow inside the valve-seat region according to several design parameters, whereas a mixed-level factorial design is used to test the significance of the effects on the response variables. In conclusion, the effects of the most significant factors on response parameters as amount of vapor formation, spray (Tau) angle, and pre-hole wall wetting are determined for further efficient design.

Iran is located at the high altitude region and has a diverse four season climate. The temperature difference of two locations at the same time reaches to 50° C. Therefore, the modern direct injection turbocharged engines are highly affected at this condition. This paper deals with the effects of temperature and pressure variations on the engine performance and fuel consumption of turbocharged Gasoline direct injection engine. Ford ecoboost is selected for this study and the base experiments are performed at the sea level. At the next step, a comprehensive one-dimensional model of the engine is constructed in GT power and validated with experimental data. Validated model is implemented to investigate the effects of ambient air variations on the engine performance and fuel consumption. The simulations revealed that low end torque is not highly affected by the temperature increase due to the turbocharging compensation while engine torque is significantly dropped at high engine speeds in the elevated temperatures. At constant air temperature, brake specific fuel consumption is decreased for higher intake pressure up to 3000 rpm and does not change up to 3500 rpm.

In this paper, the numerical simulation of the diesel and Gasoline fuels injection in a constant volume chamber is conducted under the operating conditions of a compression ignition engine with openFoam software. In order to check out the possibility of using Gasoline instead of diesel to increase the volumetric efficiency of the compression ignition engine and reduction air pollution, the spray characteristics of the Gasoline and diesel under injection pressures of 40 and 80MPa, as well as temperatures of 243, 273 and 313K, is investigated. The simulation results are compared with the experimental data derived from fast imaging techniques. The results show that under the same conditions, the vapor penetration length for the two fuels is approximately equal. Also, due to the lower volatility of the diesel fuel, its liquid penetration length in 40 and 80MPa injection pressure was found to be 7 and 9 mm higher than Gasoline, respectively, and high volatility of Gasoline leads to enough time to make air and fuel mixtures in compression ignition engine. In addition, the reduction in fuel temperature from 313K to 243K resulted an increase in the penetration of Gasoline and diesel liquids by 12 and 10 mm, respectively, and decrease in the evaporation rate, which causes a non-homogeneous mixture and an increase in unburned hydrocarbons and emissions.

Introduction: Due to the rapid growth in the urban population, the numbers of cars also have increased which resulted in an increase of pollution level in the urban areas of the developing countries. The pollutants emerging from combustion engines may include: carbon monoxide (CO), unburned hydrocarbons (UBHC), oxide of nitrogen (NOx), oxides of sulfur (SOx), particulate matter (PM), soot, hydrogen, oxygen, traces of aldehydes, alcohols, ketons, phenols, acid, lead aerosol, etc., along with normal combustion products i. e. carbon dioxide (CO2) and water vapors. In order to overcome the problems associated with the bio-fuel, the chemical substances like fuel additives derived from organic, inorganic metals were used. Fuel additives generally improve the combustion efficiency and reduce the pollution. Metallic based compounds, such as manganese, iron, copper, barium, calcium and platinum, etc., which have been used as a combustion catalyst for hydrocarbon fuels. Recent advances in nanoscience and nanotechnology enables production, control and characterization of nanoscale energetic materials. Nano materials are more effective than bulk materials because of its higher surface area. Another important advantage of nanoparticle is its size, because there is no chance for fuel injector and filter clogging as in the case of micron sized particles. Gan and Qiao, (2011) investigated the burning characteristics of fuel droplets containing nano and micron sized aluminum (Al) particles by varying its size, surfactant concentration and type of base fluid. Tyagi et al. (2008) conducted a study to improve the ignition properties of diesel fuel and investigated the influence of size and quantity of Al and Al2O3 nanoparticles in a diesel fuel. It was inferred that it shortens the ignition delay and increased the ignition probability of fuel. Finally, it was concluded that, the increase in heat and mass transfer properties of the fuel has the potential of reducing the evaporation time of droplets. In the present investigation, the effect of mixture of ethanol with Gasoline and carbon nanotubes on emission characteristics was evaluated using Jatropha biodiesel in a compression in a spark ignition engine. Materials and Methods: In this study, a mixture of ethanol with Gasoline (at five levels, 0, 10, 20, 30 and 40%) as a renewable fuel and carbon nanoparticles (at three levels of 0, 20 and 80 ppm) as catalyst were used in spark ignition engine (in 1000, 2000 and 3000 rpm). Engine pollutants such as sound, carbon monoxide, unburnt hydrocarbons, carbon dioxide and oxygen output were measured. Furthermore, a device was designed and manufactured to measure and display the amount of carbon monoxide in the exhaust outlet; moreover, if the amount of carbon increased air compressor was activated to reduce carbon monoxide in the exhaust outlet. Results and Discussion: The results showed that with increasing ethanol consumption, the amount of carbon monoxide and unburned hydrocarbons were reduced. Furthermore, the amount of produced oxygen and carbon dioxide increased. Also adding carbon nanoparticles to fuel caused the engine sound level decreased. According to the observation, carbon monoxide decreased while using an electronic device compare to the engine without a carbon monoxide controlling system. This depicts that implementation of carbon monoxide can be control and reduce which is very useful while engine is working under the close environments. Conclusions: The use of alternative fuel, Gasoline as well as the reduction of exhaust emissions in the spark ignition engine is of great importance. Therefore, in the present study five levels of ethanol (0, 10, 20, 30 and 40%) and three levels of carbon nanoparticles (0, 20 and 80 ppm) were mixed with Gasoline and used in spark ignition engine at three rotation speed (in 1000, 2000 and 3000 rpm). According to the results, there is a reduction in carbon monoxide and unburned hydrocarbons and increasing carbon dioxide emission by using ethanol, because of its fuel bound O2. Furthermore, 3. 8% dB 54% reduction in sound and CO, respectively at 3000 rpm with E10 were observed.

In a direct injection sprayer (DI), the delay time to change the concentration of chemicals in the spray tip can have a substantial effect on sprayer performance. Delay time is the most important variable in evaluating the performance of a DI system in real time herbicide application. The flow of solution from the injection point to the nozzles was mathematically modeled to quantitatively evaluate the effect of tube volume and carrier flow rate on dynamic specifications, such as delay time. Plug-Flow and Well-Mixed models were used to model solution flow in DI systems. A DI system was designed and built to allow comparison between the mathematical model and tests results. ANOVA (Duncan test) at a 5% confidence level was used to determine the effect of change of the parameters on the delay time. A factorial completely randomized block design and SPSS 15 software were used for statistical analysis of the data. Comparison of the mathematical model with the test results showed that, for time response, the Well-Mixed model had a more appropriate response time than did the Plug-Flow model. The Well-Mixed model is suggested for predicting the dynamic behavior of a DI system. Both models produced stable state values that were slightly different from test results.

Carburetor is replaced with port fuel injection systems for reduction of fuel consumption and exhaust emissions. These engines must be optimized for less exhaust emission and fuel consumption for serious emission regulations. In this paper, the effect of injection time and injection angle on the rate of fuel evaporation and emissions in the EF-7 engine has been studied, using KIVA-3V software for improvement of mixing formation process. The results show that fuel injection delay time reduces and directs injection to hot points (such as top face of valve) increasing the rate of fuel evaporation. injection with 57 degree angle improves the quality of mixture and combustion resulting in reduction of HC and CO emissions and some increase in NO emission. Other methods, such as spark ignition time adjustment, must be used for reducing NO emission.

In order to comply with stringent pollutant emissions regulations, a detailed analysis of the engine combustion and emission is required. In this field, computational tools like CFD and engine cycle simulation play a fundamental role. Therefore, the goal of the present work is to simulate a high speed DI diesel engine and study the combustion and major diesel engine emissions with more details, by using the AVL-FIRE commercial CFD code. The predicted values of the in cylinder pressure, heat release rate, emissions, spray penetration and in-cylinder isothermal contour plots by this code are compared with the corresponding experimental data in the literature and is derived good agreement. This agreement makes the model a reliable tool that can use for exploring new engine concepts.

For spark ignition engines, the fuel-air mixture preparation process is known to have a significant influence on engine performance and exhaust emissions. In this paper, an experimental study is made to characterize the spray characteristics of an injector with multi-disc nozzle used in the engine. The distributions of the droplet size and velocity and volume flux were characterized by a PDA system. Also a model of a 4 cylinders multi-point fuel injection engine was prepared using a fluid dynamics code. By this code one-dimensional, unsteady, multiphase flow in the intake port has been modeled to study the mixture formation process in the intake port. In addition, one-dimensional air flow and wall fuel film flow and a two-dimensional fuel droplet flow have been modeled, including the effects of in-cylinder mixture back flows into the port. The accuracy of model was verified using experimental results of the engine testing showing good agreement between the model and the real engine. As a result, predictions are obtained that provide a detailed picture of the air-fuel mixture properties along the intake port. A comparison was made on engine performance and exhaust emission in different fuel injection timing for 2600 and 6000 rpm and different loads. According to the present investigation, optimum injection timing for different engine operating conditions was found.