The present study focuses on the evaluation of the effect of engine parameters on the characteristics of a GDI engine by CFD analysis. The analysis was carried out at three engine speeds (2000, 3000, and 4000 rev/min), at three compression ratios (10, 11, and 12) and at three fuel injection pressures (200, 300, and 400 bar). The overall equivalence ratio of the in-cylinder mixture was maintained at 0.75 in all the above cases. Finally, it is observed that, the turbulent kinetic energy and tumble ratio were more sensitive to the engine speed than to other parameters. The fuel injection pressure was found to play a vital role in obtaining combustible mixture near the spark plug at the time of spark. In addition, a low heat release rate occurred at the engine speed of 4000 rev/min compression ratio of 10 and fuel injection pressure of 200 bar. © 2016 Faculty of Engineering, Alexandria University

J. M. Mallikarjuna

Department of Mechanical Engineering

Krishna Addepalli

Computational fluid dynamics

Engines

Fuel injection

Fuels

Kinetic energy

Kinetics

Mixtures

Speed

COMBUSTIBLE MIXTURE

ENGINE PARAMETER

GDI ENGINE

Heat Release Rate (HRR)

IN-CYLINDER MIXTURES

Parametric -analysis

Performance characteristics

Turbulent kinetic energy

Compression ratio (machinery)

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Alexandria Engineering Journal

Gasoline direct injection (GDI) engines have picked up prominence in the current circumstances in light of lower fuel consumption and exhaust emissions. Mixture formation in these engines plays a critical role which affects the combustion, performance and emission characteristics. To get better mixture formation, various factors ought to be considered, of which intake port design is one of the factors of considerable importance. Therefore, in this study, a comparison of mixture formation, performance and emission characteristics has been analyzed in a GDI engine with conventional intake port and swirl intake port. The analysis is carried out on a four-stroke wall-guided GDI engine using the computational fluid dynamics (CFD) with the help of the CONVERGE. The validation of spray breakup model is carried out to the extent possible using the experimental results available in the literature. The analysis is carried out at four overall equivalence ratios at an engine speed of 2000 rpm., and a fuel injection pressure of 100 bar using a six-hole injector. From the results, it is found that better mixture stratification, higher indicated mean effective pressure (IMEP), and lower emissions are obtained for a GDI engine with the conventional intake ports at overall equivalence ratios (ER) of 0.5 and 0.6, whereas they are better in the engine with swirl intake ports at the overall ERs of 0.7 and 0.8. © 2019 SAE International. All Rights Reserved.

SAE Technical Papers

Comparison of Conventional Intake Port and Swirl Intake Port on Mixture Formation in a GDI Engine - A CFD Analysis

The mixture formation in gasoline direct injection (GDI) engines operating at stratified condition plays an important role in deciding the combustion, performance and emission characteristics of the engine. In a wall-guided GDI engine, piston profile is such that the injected fuel is directed towards the spark plug to form a combustible mixture at the time of ignition. In these engines, fuel injection pressure and timing play an important role in creating a combustible mixture near the spark plug. Therefore, in this study, an attempt has been made to understand the effect of fuel injection pressure with single and split injection strategy on the mixture formation in a four-stroke, wall-guided GDI engine operating under stratified conditions by using computational fluid dynamics (CFD) analysis. Four fuel injection pressures viz., 90, 120, 150 and 180 bar are considered for the analysis. All the CFD simulations are carried out at the engine speed of 2000 rev/min., compression ratio of 11.5, with the overall equivalence ratio of about 0.65. The fuel injection and spark timings are maintained at 605 and 705 CADs respectively. In this study, the effect of fuel injection pressure on mixture stratification is carried out by a new parameter called "Stratification Index". It is found that, at the time of the spark, with single fuel injection, with the fuel injection pressure of 180 bar, proper mixture stratification is produced. But, with split injection mode, at all the fuel injection pressures considered, a nearly homogeneous mixture is produced. Also in the single fuel injection cases, with the fuel injection pressures of 120, 150 and 180 bar, the peak in-cylinder pressures are higher by about 4.6, 14.9 and 19.6%; and 1.5, 3.7 and 4.3% respectively, compared to that of 90 bar fuel injection pressure. Copyright © 2017 SAE International.

Effect of Fuel Injection Pressure on Mixture Stratification in a GDI Engine - A CFD Analysis

This paper deals with the in-cylinder flow field analysis in a two-stroke engine under motoring conditions by particle image velocimetry (PIV) and computational fluid dynamics (CFD). The main objective is to analyze the effect of engine parameters viz., engine speed, compression ratio (CR) and port orientation on the in-cylinder flows in a loop-scavenged two-stroke gasoline direct injection (GDI) engine, with an aim to help researchers to design fuel efficient and less polluting two-stroke engines. In this study, a single-cylinder 70 cm3 two-stroke engine which is very commonly used for the two-wheeler application, is considered. The engine cylinder is modified to provide optical access into the in-cylinder region. The PIV experiments are conducted at various engine speeds viz., 500, 1000 and 1500 rev/min, and the plane averaged velocity vector fields obtained, are analyzed to understand the in-cylinder flow behavior. The CFD study is also carried out using the commercial CFD code, STARCD, to study and compare the in-cylinder flow parameters at various engine operating conditions. The CFD results are compared with the experimental results to the extent possible. The CFD predictions are found to be in good agreement with the experimental results. Therefore, the CFD analysis has been extended further to understand the effect of various engine parameters on the in-cylinder flows. We found that the turbulent kinetic energy and tumble ratio increased by about 25% and 20% respectively, when the engine speed was increased from 1000 to 1500 rev/min. Also, we found that the turbulent kinetic energy and tumble ratio decreased by about 13% and 26% when the compression ratio was increased from 7 to 8. In addition, we found that the port orientation, rather than port areas had a greater influence on the in-cylinder flow parameters. © 2016 Elsevier Ltd.

Applied Energy

Effect of engine parameters on in-cylinder flows in a two-stroke gasoline direct injection engine

This paper deals with in-cylinder flow field analysis in a motored two-stroke engine by CFD technique using STAR-CD. The main aim of this study is to find out the best turbulence model which predicts the fluid flow field inside the cylinder of a two-stroke engine. In this study, a single-cylinder, two-stroke engine which is very commonly used for two-wheeler application in India is considered. Entire analysis is done at an engine speed of 1500 rev/min. under motoring conditions. Here, three commonly used turbulence models viz. standard k-, Chen k- and RNG k- are considered. In addition, experiments were also conducted on the above engine at the motoring conditions to measure velocity vectors of in-cylinder flow fields using particle image velocimetry (PIV). The results of PIV were also used for validating the CFD predictions. For analyzing and comparison of the results, turbulent kinetic energy (TKE), tumble ratio (TR) and, axial and radial velocities at known locations inside the engine cylinder were considered. From the analysis of results, it is found that RNG k- turbulence model best predicts the in-cylinder flow fields in a two-stroke engine. Copyright © 2013 SAE International.

In-cylinder flow analysis in a two-stroke engine - A comparison of different turbulence models using CFD

Applied Thermal Engineering

Numerical investigation of stratified air/fuel preparation in a GDI engine

Fuel

Numerical study of the effect of piston top contour on GDI engine performance under catalyst heating mode

SAE International Journal of Engines

A Study of a Multistage Injection Mechanism for Improving the Combustion of Direct-Injection Gasoline Engines

Parametric analysis of a 4-stroke GDI engine using CFD

Journal	Data powered by TypesetAlexandria Engineering Journal
Publisher	Data powered by TypesetElsevier B.V.
ISSN	11100168
Open Access	Yes