Assessment and Validation of Internal Aerodynamics and Mixture Preparation in Spark-Ignition Engine Using LES Approach

2020 ◽  
Author(s):  
Martin Ritter ◽  
Louis-Marie Malbec ◽  
Olivier Laget
Author(s):  
Nicolas Iafrate ◽  
Anthony Robert ◽  
Jean-Baptiste Michel ◽  
Olivier Colin ◽  
Benedicte Cuenot ◽  
...  

Downsized spark ignition engines coupled with a direct injection strategy are more and more attractive for car manufacturers in order to reduce pollutant emissions and increase efficiency. However, the combustion process may be affected by local heterogeneities caused by the interaction between the spray and turbulence. The aim for car manufacturers of such engine strategy is to create, for mid-to-high speeds and mid-up-high loads, a mixture which is as homogeneous as possible. However, although injection occurs during the intake phase, which favors homogeneous mixing, local heterogeneities of the equivalence ratio are still observed at the ignition time. The analysis of the mixture preparation is difficult to perform experimentally because of limited optical accesses. In this context, numerical simulation, and in particular Large Eddy Simulation (LES) are complementary tools for the understanding and analysis of unsteady phenomena. The paper presents the LES study of the impact of direct injection on the mixture preparation and combustion in a spark ignition engine. Numerical simulations are validated by comparing LES results with experimental data previously obtained at IFPEN. Two main analyses are performed. The first one focuses on the fuel mixing and the second one concerns the effect of the liquid phase on the combustion process. To highlight these phenomena, simulations with and without liquid injection are performed and compared.


2020 ◽  
Vol 5 (3-4) ◽  
pp. 147-157
Author(s):  
Nicolas Wippermann ◽  
Olaf Thiele ◽  
Olaf Toedter ◽  
Thomas Koch

Abstract This paper investigates the local air-to-fuel ratio measurement within the pre-chamber of a spark-ignition engine by determining the absorption of light from hydrocarbons using an infrared sensor. The measurement was performed during fired and motored engine operation points and compared to the more common exhaust lambda measurements. The experiment provided data to compare the mixture preparation in a hot and cold environment of pre-chamber and main combustion chamber. The experiment also gives an indication regarding the possible use of a pre-chamber sensor in a motored engine at higher boost pressures and fuel mass flows, operation points that would overheat the sensor in a fired engine. The work also includes the analysis of the fuel delivery into the pre-chamber of a direct and indirect injection engine. Furthermore, pressure and temperature measurement within the pre-chamber provides information about the critical sensor environment and helps to understand the gas exchange between the two volumes.


2002 ◽  
Vol 24 (4) ◽  
pp. 209-218
Author(s):  
Bui Van Ga ◽  
Duong Viet Dung ◽  
Tran Van Nam

Based on the mathematical validated by experimental data, the present paper introduces the evolution of concentration and velocity fields of Liquefield Petroleum Gas (LPG) jet in combustion chamber of spark ingnition enegine under effects of injection conditions and surrounding environment. The results allow us to predict the development of jet for an efficient organization of mixture preparation and combustion process in LPG direct injection spark ignition engine


1976 ◽  
Vol 190 (1) ◽  
pp. 13-21 ◽  
Author(s):  
N R Beale ◽  
D Hodgetts

SYNOPSIS. Mixture quality and turbulence in the isolated cylinder of a multi-cylinder spark ignition engine were changed by the method of mixture preparation in the induction tract and by the increase of mixture flow velocity through the valve aperture which was varied by the change of the full lift of the inlet valve. The fuel consumption and the mass rates of the emissions of carbon monoxide, nitric oxide and hydrocarbons of the engine when controlled with a conventional throttle are compared with those of the valve throttled engine. The employment of exhaust gas recirculation is shown to have a decisive effect on the comparison and to be essential for low emissions from a valve throttled engine.


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