New Mixture Formation Technology of Direct Fuel Injection Stratified Charge SI Engine (OSKA) - Test Result with Gasoline Fuel

1988 ◽  
Author(s):  
Satoshi Kato ◽  
Shigeru Onishi
Keyword(s):  
Fuel Injection ◽  
Si Engine ◽  
Mixture Formation ◽  
Stratified Charge ◽  
Direct Fuel Injection ◽  
Test Result

Study of Mixture Formation on Gasoline Direct Fuel Injection Engines

2002 ◽  
Vol 2002 (0) ◽  
pp. 57-58
Author(s):  
Noboru TOKUYASU ◽  
Yoshihiro SUKEGAWA ◽  
Toshiharu NOGI
Keyword(s):  
Fuel Injection ◽  
Mixture Formation ◽  
Direct Fuel Injection

Stable Fuel Confinement in Stratified Charge GDI Engines

2004 ◽  
Author(s):  
S. Zanforlin ◽  
R. Gentili
Keyword(s):  
Fuel Injection ◽  
Ignition Time ◽  
Stable Stratification ◽  
Operating Conditions ◽  
Stratified Charge ◽  
Fuel Distribution ◽  
Fuel Loss ◽  
Cylinder Flow ◽  
Gdi Engines ◽  
Direct Fuel Injection

Direct fuel injection combined with charge stratification represents a must for two-stroke S.I. engines, since it prevents fuel loss from the exhaust port and incomplete combustion or misfire at light loads. The most difficult aims are keeping stable stratification when engine operating conditions change and, at very light loads, avoiding excessive dilution and spreading of fuel vapour in consequence of burned gas expansion. Two new-concept engine designs are proposed in this paper. In both cases shapes of piston and head, together with scavenging-duct orientation have been optimised to obtain stable in-cylinder flow field features (independently of engine speed) and proper fuel distribution at ignition time. Computational Fluid Dynamics (CFD) predictions at different loads and speeds are reported and discussed.

scholarly journals COMPARISON OF COMBUSTION INDICATORS OF TWO-STROKE ENGINES WITH A CARBURETOR AND DIRECT FUEL INJECTION

2021 ◽  
pp. 35-44
Author(s):  
V.A. Korohodskyi
Keyword(s):  
Heat Release ◽  
Fuel Injection ◽  
Combustion Process ◽  
Expansion Ratio ◽  
Mixture Formation ◽  
Load Characteristic ◽  
Combustion Pressure ◽  
Maximum Value ◽  
Characteristic Modes ◽  
Direct Fuel Injection

The subject matter of study in the article is the indicators of the combustion process of a two-stroke engine 1D 8.7 / 8.2 with spark ignition when using a carburetor power supply system (external mixture formation) and a direct fuel injection system (internal mixture formation). Internal mixture formation ensures the organization of a stratified fuel-air charge (SFAC) and a stratified lean fuel-air charge (SLFAC). Combustion indicators allow you to assess the nature of the combustion process. The goal is to determine the nature of the change in the combustion indicators of the engine with external and internal mixture formation during the organization of the working process with the SFAC and SLFAC at the load characteristic modes (n = 3,000 rpm). The tasks to be solved are as follows. The use of internal mixture formation and the organization of the combustion of SLFAC and SFAC made it possible to obtain values of ηi greater than with external mixture formation at all modes of the load characteristic. The maximum value of ηi for SLFAC is 0.5 at a load bmep = 0.2 MPa, for SFAC – 0.44 at bmep = 0.25 MPa and 0.3 at bmep = 0.36 MPa for an engine with a carburettor. Maximum combustion pressure (рz), pressure increase ratio (λ), preliminary expansion ratio (ρ), further expansion ratio (δ), combustion character indicator (m), maximum heat release rate (dx / dfi max), duration of combustion from TDC to point Z (φz), total duration of combustion (dφz); to construct the characteristics of changes in combustion indicators and to obtain empirical dependences depending on the engine load. An experimental-analytical research method is used, which provides for the determination of the nature and analysis of the course of the combustion process according to the combustion indicators established by the experimental indicator diagrams. The following results were obtained. The use of internal mixture formation and the organization of the combustion of SFAC and SLFAC made it possible to obtain ηi values greater than with external mixture formation at all modes of the load characteristic. The maximum value of ηi for SLFAC is 0.5 at a load ре = 0.2 MPa, for SFAC - 0.44 at ре = 0.25 MPa and 0.3 at ре = 0.36 MPa for an engine with a carburetor. The pressure in the cylinder with the piston position at TDC is on average 1.5 times higher for an engine with a carburetor, and the maximum combustion pressure рz is higher up to 11 % with the organization of SLFAC (the degree of pressure increase λ is reduced by 26 %) and 20-22 % higher than in the organization of SFAC (the value of λ is reduced by 31 %). An increase in the compression ratio ε by 26.4 % and a decrease in the degree of preliminary expansion ρ at SLFAC in comparison with SFAC made it possible to increase the degree of further expansion δ by an average of 30 % and by 43 % in comparison with the carburetor power system. When organizing SLFAC, the value of the indicator of the nature of combustion m is, on average, 1.4 times higher than that of an engine with a carburetor and 1.45 times higher relative to the organization of SFAC, at which the maximum rate of heat release dx / dfi max is up to 40 % higher than in the engine with carburetor. The SLFAC organization allowed reduce the combustion duration by 39 % relative to external mixture formation and by 36 % relative to the SFAC organization. Conclusions. The scientific novelty of the results obtained consists in obtaining data and empirical dependences of the indicators of the combustion process of the 1D 8.7 / 8.2 engine with external and internal mixture formation with the organization of SFAC and SLFAC at load characteristic modes (n = 3,000 rpm). It was found that the best technical, economic and environmental indicators correspond to the organization of internal mixing with SLFAC.

Study on Different Flame Jet Ignition Variants in a Stratified Charge Spark Ignition Engine

2002 ◽  
Author(s):  
Edward Rakosi ◽  
Radu Rosca
Keyword(s):  
Combustion Chamber ◽  
Fuel Consumption ◽  
Output Power ◽  
Cylinder Head ◽  
Fuel Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Working Process ◽  
Stratified Charge ◽  
Direct Fuel Injection

The paper presents some experimental results regarding a stratified charge spark ignition engine. We have applied the divided combustion chamber concept, using a flame jet in order to ignite the fuel-air mixture. The fueling system was a combined one: the cylinder head combustion chamber (secondary, auxiliary) was fueled by direct fuel injection, while the main combustion chamber was fueled with lean mixture by the means of a carburetor. During the tests we have used two types of main combustion chamber and three types of secondary combustion chamber. Thus, we had the possibility to use different compression ratios, starting with the lower ones, imposed by the less volatile fuels and ending with the higher ones, that led to the highest output power and a steady working process. In the meantime, three types of spark plugs were tested. We have also studied the HC and CO emissions, as well as the fuel consumption.

Direct Injection and Charge Stratification in a 50 cc Two-Stroke Engine: CFD Studies and Test Bench Results

2006 ◽  
Author(s):  
S. Zanforlin ◽  
E. Musu ◽  
S. Frigo ◽  
R. Gentili
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Gas Analysis ◽  
Stratified Charge ◽  
Wall Film ◽  
Fuel Loss ◽  
Engine Stability ◽  
Time Required ◽  
Direct Fuel Injection ◽  
The Eu

Direct fuel injection has become necessary in two-stroke S.I. engines, since it prevents one of the major problems of these engines, that is fuel loss from the exhaust port. Another important problem is combustion irregularity at light loads, due to excessive residual gas in the charge, and can be solved by charge stratification. High-pressure liquid fuel injection is able to control the mixing process inside the cylinder for getting either stratified charge at partial loads or quasi-stoichiometric conditions, as it is required at full load. The feasibility of this solution for a small engine for light motorcycles has been studied using CFD tools. An exhaustive investigation carried out by the KIVA3v code allowed to design a 50 cm3 engine prototype with a satisfactory behaviour even at light loads in unthrottled condition, as proved by good fuel economy and engine stability in dynamometric bench tests. Exhaust gas analysis and indicated pressure behaviour confirm stratification and combustion correctness. For the final part of the research the adoption of the AVL-Fire code has been considered: the possibility to take into account any combustion chamber and transfer duct geometric details and the accuracy of spray breakup and wall film models allow to better understand the engine behaviour throughout the operating range, obtaining useful information in order to efficiently shorten the experimental time required for the EU map-setting.

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