Three-Dimensional Simulation of Pollutant Formation in a DI Diesel Engine Using Multiple Interactive Flamelets

1998 ◽  
Author(s):  
H. Barths ◽  
C. Antoni ◽  
N. Peters
Author(s):  
A. Abd El-Sabor Mohamed ◽  
Saleh Abo-Elfadl ◽  
Abd El-Moneim M. Nassib

The in-cylinder airflow motion is an important factor that severely affects combustion efficiency and emissions in diesel engines. It is greatly affected by the inlet port and valve geometries. A diesel engine cylinder with a helical–spiral inlet port is used in this study. An ordinary inlet valve and shrouded inlet valve having different shroud and orientation angles are used to study the shroud effect on the swirl and tumble motion inside the engine cylinder. Four shroud angles of 90 deg, 120 deg, 150 deg, and 180 deg are used. With each shroud angle, four orientation angles of 0 deg, 30 deg, 60 deg, and 90 deg are also used. Three-dimensional simulation model using the shear stress transport (SST) k–ω model is used for simulating air flow through the inlet port, inlet valve, and engine cylinder during both the intake and compression strokes. The results showed that increasing the valve shroud angle increases the swirl, and the maximum increase occurs at a valve shroud angle of 180 deg and orientation angle of 0 deg with a value of 80% with respect to the ordinary valve. But it decreases the volumetric efficiency, and the maximum decrement occurs at valve shroud of 180 deg and orientation angle of 90 deg with a value of 5.98%. Variations of the shroud and orientation angles have very small effect on the tumble inside the engine cylinder.


Author(s):  
Kamran Poorghasemi ◽  
Fathollah Ommi ◽  
Vahid Esfahanian

In DI Diesel engines NO and Soot trade off is an important challenge for Engineers. In this paper, at first, multiple injection strategy will be introduced as a useful way to reduce both NO and Soot emissions simultaneously. Then the effect of injection pressure in post injection on the engine emissions will be studied. Investigations have been conducted on DI diesel engine. To evaluate the benefits of multiple injection strategies and to reveal combustion mechanism, modified three dimensional CFD code KIVA-3V was used. Results showed that using post injection with appropriate dwell between injection pulses can be effective in simultaneously reduction of emissions. Based on computation results, NO reduction formation mechanism is a single injection with retarded injection timing. It is shown that reduced soot formation is because of the fact that the soot producing rich regions at the fuel spray head are not replenished by new fuel when the injection is stopped and then restarted. Also increasing injection pressure in post injection will reduce the Soot emission dramatically while NO is in control and it is due to increasing fuel burning rate in post injection pulse.


2009 ◽  
Vol 137 (2) ◽  
pp. 37-49
Author(s):  
Robin VANHAELST ◽  
Werner HENTSCHEL ◽  
Christian MÜLLER ◽  
Jakub CZAJKA

In this paper the systematic development of an optical swirl sensor to measure the swirl ratio in an operating serial turbocharged DI-diesel engine is described. The optical sensor detects the visible light of the combustion, in particular the emission of the sooting flame in a wavelength range from 600 nm up to 1000 nm. The acceptance angle is so small that the soot clouds from every spray can be detected as they are being turned under the optical sensor by the swirling flow. In a first part the new optical probe method was validated on a transparent engine by comparison with high speed video recordings. In the second part several hardware variations were made on a serial DI-diesel engine which was equipped with a variable swirl valve. The influence of the opened- and closed swirl valve constellation and the piston geometry on the swirl ratio was measured with the optical probe technique. The results were compared with a zero dimensional simulation model. There was a good agreement between the swirl measurements and the 0D-model. The optical swirl sensor has proven to be a powerful tool to optimise the combustion process. Without any modifications on the cylinder head, the effect of application parameters and hardware parts on the swirl strength can be quantified for all engine loads and speeds.


2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Mohamed A. Bassiony ◽  
Abdellatif M. Sadiq ◽  
Mohammed T. Gergawy ◽  
Samer F. Ahmed ◽  
Saud A. Ghani

New induction manifold designs have been developed in this work to enhance the turbulence intensity and improve the mixing quality inside diesel engine cylinders. These new designs employ a spiral-helical shape with three different helical diameters (1D, 2D, 3D; where D is the inner diameter of the manifold) and three port outlet angles: 0 deg, 30 deg, and 60 deg. The new manifolds have been manufactured using three-dimensional printing technique. Computational fluid dynamics simulations have been conducted to estimate the turbulent kinetic energy (TKE) and the induction swirl generated by these new designs. The combustion characteristics that include the maximum pressure raise rate (dP/dθ) and the peak pressure inside the cylinder have been measured for a direct injection (DI) diesel engine utilizing these new manifold designs. In addition, engine performance and emissions have also been evaluated and compared with those of the normal manifold of the engine. It was found that the new manifolds with 1D helical diameter produce a high TKE and a reasonably strong induction swirl, while the ones with 2D and 3D generate lower TKEs and higher induction swirls than those of 1D. Therefore, dP/dθ and peak pressure were the highest with manifolds 1D, in particular manifold m (D, 30). Moreover, this manifold has provided the lowest fuel consumption with the engine load by about 28% reduction in comparison with the normal manifold. For engine emissions, m (D, 30) manifold has generated the lowest CO, SO2, and smoke emissions compared with the normal and other new manifolds as well, while the NO emission was the highest with this manifold.


2013 ◽  
Vol 37 (2) ◽  
pp. 247-257 ◽  
Author(s):  
Reza Rahimi ◽  
S. Jafarmadar ◽  
Sh. Khalilarya ◽  
A. Mohebbi

This paper presents the results of numerical and experimental investigations to evaluate the distribution of exhaust gas recirculation (EGR) between cylinders in a DI turbocharged diesel engine. The turbulent three-dimensional flow field was analyzed by the numerical solution of conservation equations with an appropriate turbulence model. EGR was applied to intake manifold with various rates at cooled and non-cooled states. The experiments were conducted on an MT4.244 turbocharged DI diesel engine under full load condition at 1900rpm. The model was validated by experimental data with a good agreement between experimental measurements and numerical predictions. Using this method, it is possible to control EGR distribution so as to reduce emissions formation as well as to improve performance.


2001 ◽  
Author(s):  
Jesús Benajes ◽  
Xandra Margot ◽  
José V. Pastor ◽  
Antonio Gil

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