Modeling Mixture Formation in a Gasoline Direct Injection Engine

2005 ◽  
Vol 73 (6) ◽  
pp. 931-939 ◽  
Author(s):  
Rossella Rotondi

Mixture formation and combustion in a gasoline direct injection (GDI) engine were studied. A swirl-type nozzle, with an inwardly opening pintle, was used to inject the fuel directly in a four stroke, four cylinder, four valves per cylinder engine. The atomization of the hollow cone fuel spray was modeled by using a hybrid approach. The most important obstacle in the development of GDI engines is that the control of the stratified-charge combustion over the entire operating range is very difficult. Since the location of the ignition source is fixed in SI engines the mixture cloud must be controlled both temporally and spatially for a wide range of operating conditions. Results show that the volume of the spark must be considered when discretizing the computational domain because it highly influences the flow field in the combustion chamber. This is because the volume occupied by the plug cannot be neglected since it is much bigger than the ones used in port fuel injection engines. The development of a successful combustion system depends on the design of the fuel injection system and the matching with the in-cylinder flow field: the stratification at part load appears to be the most crucial and critical step, and if the air motion is not well coupled with the fuel spray it would lead to an increase of unburned hydrocarbon emission and fuel consumption

Author(s):  
S Tonini ◽  
M Gavaises ◽  
C Arcoumanis ◽  
A Theodorakakos ◽  
S Kometani

A multi-component fuel vaporization model has been developed and implemented into an in-house multi-phase computational fluid dynamics flow solver simulating the flow, spray, and air-fuel mixing processes taking place in gasoline direct injection (GDI) engines. Multi-component fuel properties are modelled assuming a specified composition of pure hydrocarbons. High-pressure and -temperature effects, as well as gas solubility and compressibility, are considered. Remote droplet vaporization is initially investigated in order to quantify and validate the most appropriate vaporization model for conditions relevant to those realized with GDI engines. Phenomena related to the fuel injection system and pressure-swirl atomizer flow as well as the subsequent spray development are considered using an one-dimensional fuel injection equipment model predicting the wave dynamics inside the injection system, a Eulerian volume of fluid-based two-phase flow model simulating the liquid film formation process inside the injection hole of the swirl atomizer and a Lagrangian spray model simulating the subsequent spray development, respectively. The computational results are validated against experimental data obtained in an optical engine and include laser Doppler velocimetry measurements of the charge air motion in the absence of spray injection and charge coupled device images of the fuel spray injected during the induction stroke. The results confirm that fuel composition affects the overall fuel spray vaporization rate, but not significantly relative to other flow and heat transfer processes taking place during the engine operation.


2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Nikhil Sharma ◽  
Avinash Kumar Agarwal

Abstract Fuel availability, global warming, and energy security are the three main driving forces, which determine suitability and long-term implementation potential of a renewable fuel for internal combustion engines for a variety of applications. Comprehensive engine experiments were conducted in a single-cylinder gasoline direct injection (GDI) engine prototype having a compression ratio of 10.5, for gaining insights into application of mixtures of gasoline and primary alcohols. Performance, emissions, combustion, and particulate characteristics were determined at different engine speeds (1500, 2000, 2500, 3000 rpm), different fuel injection pressures (FIP: 40, 80, 120, 160 bars) and different test fuel blends namely 15% (v/v) butanol, ethanol, and methanol blended with gasoline, respectively (Bu15, E15, and M15) and baseline gasoline at a fixed (optimum) spark timing of 24 deg before top dead center (bTDC). For a majority of operating conditions, gasohols exhibited superior characteristics except minor engine performance penalty. Gasohols therefore emerged as serious candidate as a transitional renewable fuel for utilization in the existing GDI engines, without requirement of any major hardware changes.


Author(s):  
Zhang Ming ◽  
Zhong Jun ◽  
Capelli Stefano ◽  
Lubrano Luigi

The development process of a down-sized turbocharged gasoline direct-injection (GDI) engine/vehicle was partially introduced with the focus on particulate matter (PM)/particle number (PN) emission reduction. To achieve this goal, the injection system was upgraded to obtain higher injection pressure. Two types of prototype injectors were designed and compared under critical test conditions. Combined numerical and experimental analysis was made to select the right injector in terms of particle emission. With the selected injector, the effect of injection parameters calibration (injection pressure, start of injection (SOI) timing, number of injection pulses, etc.) on PM/PN emission was illustrated. The number of fuel injection pulses, SOI timing, and injection pressure were found playing the leading role in terms of the particle emission suppression. With single-injection strategy, the injection pressure and SOI timing were found to be a dominant factor to reduce particle emission in warm-up condition and cold condition, respectively; a fine combination of injection timing and injection pressure is generally able to decrease up to 50% of PM emission in a wide range of the engine map. While with multiple injection, up to an order of magnitude PM emission reduction can be achieved. Several New European Driving Cycle (NEDC) emission cycles were arranged on a demo vehicle to evaluate the effect of the injection system upgrade and adjusted calibration. This work will provide a guide for the emission control of GDI engines/vehicles fulfilling future emission legislation.


Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 277
Author(s):  
Wen-Chang Tsai

The fuel injection system is one of the key components of an in-cylinder direct injection engine. Its performance directly affects the economy, power and emission of the engine. Previous research found that the Taguchi method can be used to optimize the fuel injection map and operation parameters of the injection system. The electronic control injector was able to steadily control the operation performance of a high-pressure fuel injection system, but its control was not accurate enough. This paper conducts an experimental analysis for the fuel injection quantity of DI injectors using the Taguchi-Regression approach, and provides a decision-making analysis to improve the design of electronic elements for the driving circuit. In order to develop a more stable and energy-saving driver, a functional experiment was carried out. The hybrid Taguchi-regression algorithm for injection quantity of a direct injection injector was examined to verify the feasibility of the proposed algorithm. This paper also introduces the development of a high-pressure fuel injection system and provides a new theoretical basis for optimizing the performance of an in-cylinder gasoline direct injection engine. Finally, a simulation study for the fuel injection control system was carried out under the environment of MATLAB/Simulink to validate the theoretical concepts.


2018 ◽  
Vol 172 (1) ◽  
pp. 35-43
Author(s):  
Maciej SIDOROWICZ ◽  
Ireneusz PIELECHA

Direct fuel injection requires appropriate conditions for proper ignition of the formed mixture. The proper combustion process is shaped by the direct fuel injection, whose parameters vary. Preparation of the dose requires proper injector placement in the combustion chamber. This article focuses on the issue of the injector specific spatial and angular position in order to implement the injection and atomization of the fuel. The injectors pseudo-optimal location has been presented along with several changed positions. The research was conducted as a simulation experiment using AVL FIRE 2017 software. The best position of the injector was selected based on the fuel spraying and injection process indicators. It has been shown that the spatial position has the most impact and the injector placement angle is of secondary importance.


Author(s):  
Y Zhu ◽  
H Zhao ◽  
N Ladommatos

The piston bowl design is one of the most important factors that affect the air-fuel mixing and the subsequent combustion and pollutant formation processes in a direct-injection diesel engine. The bowl geometry and dimensions, such as the pip region, bowl lip area, and toroidal radius, are all known to have an effect on the in-cylinder mixing and combustion process. In order to understand better the effect of re-entrant geometry, three piston bowls with different toroidal radii and lip shapes were investigated using computational fluid dynamics engine modelling. KIVA3V with improved submodels was used to model the in-cylinder flows and combustion process, and it was validated on a high-speed direct-injection engine with a second-generation common-rail fuel injection system. The engine's performance, in-cylinder flow, and combustion, and emission characteristics were analysed at maximum power and maximum torque conditions and at part-load operating conditions. Three injector protrusions and injection timings were investigated at full-load and part-load conditions.


Author(s):  
N. A. Henein ◽  
I. P. Singh ◽  
L. Zhong ◽  
Y. Poonawala ◽  
J. Singh ◽  
...  

This paper introduces a phenomenological model for the fuel distribution, combustion, and emissions formation in the small bore, high speed direct injection diesel engine. A differentiation is made between the conditions in large bore and small bore diesel engines, particularly regarding the fuel impingement on the walls and the swirl and squish gas flow components. The model considers the fuel injected prior to the development of the flame, fuel injected in the flame, fuel deposited on the walls and the last part of the fuel delivered at the end of the injection process. The model is based on experimental results obtained in a single-cylinder, 4-valve, direct-injection, four-stroke-cycle, water-cooled, diesel engine equipped with a common rail fuel injection system. The engine is supercharged with heated shop air, and the exhaust back pressure is adjusted to simulate actual turbo-charged diesel engine conditions. The experiments covered a wide range of injection pressures, EGR rates, injection timings and swirl ratios. Correlations and 2-D maps are developed to show the effect of combinations of the above parameters on engine out emissions. Emphasis is made on the nitric oxide and soot measured in Bosch Smoke Units (BSU).


2001 ◽  
Vol 2001 (0) ◽  
pp. 149-150
Author(s):  
Yoko NAKAYAMA ◽  
Takuya SHIRAISHI ◽  
Toshiharu NOGI ◽  
Mamoru FUJIEDA

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