Plenum

In automotive technology, an intake manifold is the component of an engine that transports the air-fuel mixture to the engine cylinders. The main purpose of the intake manifold is to evenly distribute the combustion mixture to each intake port of the engine cylinder. Even distribution is important to optimize the volumetric efficiency and performance of the engine, but the major problem in the thesis was to identify that; to achieve the even distribution of flow at each cylinders, to select the best turbulence model for the analysis of manifold using computational fluid dynamics, to achieve the maximum mass flow rate through the restricted size C-D nozzle, to maintain the equal pressure throughout the plenum, to propagate back the higher pressure column of air to intake port within the duration of the intake valve’s closure. To achieve the even flow of distribution and improve the volumetric efficiency, author divided his analysis into three different part restrictor, plenum, and cylinder runner and then analyzed the final intake manifold. Dividing the work into three different part and then combine them as single manifold part provide the greater refinement in the result and act as meshing of manifold. To select the best turbulence model for this study, author took the design data of existing experimental model and find that Spalart-Allmaras model was approximately same as the experimental model. For designing the nozzle, author selected the four design variables; nozzle inlet diameter, inlet curvature radius, diffuser half angle and diffuser length with five level of each variable. With these four variable and five level of each variable, author had need to perform 625 experiments, but he design the matrix by the help of Taguchi method using statistical tool “Minitab” and perform only 25 experiment in CFD package “Ansys Fluent”, to find the best result for restrictor, author again use the statistical tool to analyze the design matrix, and then predict the best result for restrictor. To propagate back the higher pressure column of air to intake port within the duration of the intake valve’s closure, author use the Ram Theory and Helmholtz theory to calculate the runner length and diameter as well as total distance traveled by the pressure column during the intake valve closure. To find out the pressure variation in cylinder runner due to intake valve opening and closing, author design virtual engine of the same specification of Kawasaki Ninja ZX-6R by using leading engine designing software “Ricardo Wave”, and then use these pressure data to develop the transient boundary condition in “Ansys Fluent”. To achieve the static pressure inside the plenum and distribute the combustible air evenly to each intake runner, author select two design variables; plenum shape (rectangular, circular, elliptical and curved) and plenum size (2.0litre, 2.25litre, 2.5litre, 2.75litre and 3.0litre). To find the best result for plenum, author perform the experiment in Ansys Fluent for all possible experiment and find the curved and elliptical shape plenum were providing higher volumetric efficiency, static plenum pressure and even flow of distribution to each cylinder. For designing final intake manifold author select the best design from all three part; restrictor, cylinder runner, plenum; and perform the experiment using computational fluid dynamics software Ansys Fluent, and in result he find that plenum with 2.5litre size curved shape with restrictor of 48mm nozzle inlet diameter, 41mm inlet curvature radius, 152mm diffuser length, and 30and 70 diffuser half angle. Keywords: Intake Manifold, Plenum, Restrictor, Cylinder Runner, Volumetric Efficiency, Computational Fluid Dynamics

In automotive technology, an intake manifold is the component of an engine that transports the air-fuel mixture to the engine cylinders. The main purpose of the intake manifold is to evenly distribute the combustion mixture to each intake port of the engine cylinder. Even distribution is important to optimize the volumetric efficiency and performance of the engine, but the major problem in the thesis was to identify that; to achieve the even distribution of flow at each cylinders, to select the best turbulence model for the analysis of manifold using computational fluid dynamics, to achieve the maximum mass flow rate through the restricted size C-D nozzle, to maintain the equal pressure throughout the plenum, to propagate back the higher pressure column of air to intake port within the duration of the intake valve’s closure. To achieve the even flow of distribution and improve the volumetric efficiency, author divided his analysis into three different part restrictor, plenum, and cylinder runner  and then analyzed the final intake manifold. Dividing the work into three different part and then combine them as single manifold part provide the greater refinement in the result and act as meshing of manifold.
To select the best turbulence model for this study, author took the design data of existing experimental model and find that Spalart-Allmaras model was approximately same as the experimental model. For designing the nozzle, author selected the four design variables; nozzle inlet diameter, inlet curvature radius, diffuser half angle and diffuser length with five level of each variable. With these four variable and five level of each variable, author had need to perform 625 experiments, but he design the matrix by the help of Taguchi method using statistical tool “Minitab” and perform only 25 experiment in CFD package “Ansys Fluent”, to find the best result for restrictor, author again use the statistical tool to analyze the design matrix, and then predict the best result for restrictor. To propagate back the higher pressure column of air to intake port within the duration of the intake valve’s closure, author use the Ram Theory and Helmholtz theory to calculate the runner length and diameter as well as total distance traveled by the pressure column during the intake valve closure. To find out the pressure variation in cylinder runner due to intake valve opening and closing, author design virtual engine of the same specification of Kawasaki Ninja ZX-6R by using leading engine designing software “Ricardo Wave”, and then use these pressure data to develop the transient boundary condition in “Ansys Fluent”. To achieve the static pressure inside the plenum and distribute the combustible air evenly to each intake runner, author select two design variables; plenum shape (rectangular, circular, elliptical and curved) and plenum size (2.0litre, 2.25litre, 2.5litre, 2.75litre and 3.0litre). To find the best result for plenum, author perform the experiment in Ansys Fluent for all possible experiment and find the curved and elliptical shape plenum were providing higher volumetric efficiency, static plenum pressure and even flow of distribution to each cylinder.
For designing final intake manifold author select the best design from all three part; restrictor, cylinder runner, plenum; and perform the experiment using computational fluid dynamics software Ansys Fluent, and in result he find that plenum with 2.5litre size curved shape with restrictor of 48mm nozzle inlet diameter, 41mm inlet curvature radius, 152mm diffuser length, and 30and 70 diffuser half angle. 

Keywords: Intake Manifold, Plenum, Restrictor, Cylinder Runner, Volumetric Efficiency, Computational Fluid Dynamics

This review paper contains the basic concept of intake manifold. Intake manifold is the breathing system of the car engine which supplies air to the engine cylinders where the combustion of the fuel occurs. The review paper contain SAE is the society of automotive engineers which is working for the automotive industry, educators and students. SAE India organizes formula student car racing championship name SUPRA every year. In this event a team of students has to follow all rules and regulations provided in rulebook which is designed by SAE committee. This paper contains basic methodology and technology adopted for designing intake manifold for 600 cc SUZUKI GSXR bike engine.

CFD elaborates itself as computational fluid dynamics is a numerical technique to understand vide variety of complex flows in various engineering components. It helps at an earlier stage to analyze, optimize and predict the performance of component to make better decisions. Application of it are in various fields ranging from aerodynamics to HVAC internal flow in a duct system. The paper tries to compare the hand calculation with the cfd results for a 3d plenum box. Investigating for a better optimized design. Various factors like velocity, flowrate, backpressure etc. are taken into consideration.

Intake manifold is the part of an engine that supplies the fuel/air mixture to the cylinder. The intake manifold is essential for the optimal performance of an internal combustion engines. Intake manifold is the breathing system of the car engine which supplies air to the engine cylinders where the combustion of the fuel occurs. The primary function of the intake manifold is to evenly distribute the combustion mixture (or just air in a direct injection engine) to each intake port in the cylinder head. Even distribution is important to optimize the efficiency and performance of the engine. It may also serve as a mount for the carburetor, throttle body, fuel injectors and other components of the engine. Due to the downward movement of the pistons and the restriction caused by the throttle valve, in a reciprocating spark ignition piston engine, a partial vacuum (lower than atmospheric pressure) exists in the intake manifold. This review paper has main aim is the gain understanding of the flow characteristics inside an intake manifold which is fitted with an intake restrictor. Geometrical design of intake manifold is very important for the good performance of an IC engine. Unequal velocity distribution of intake air of runner's outlets of intake manifold makes it less efficient. The reported works aims to makes this unequal velocity distribution of velocity in nearly equal manner with increase of velocity at outlet without any major modification in design of intake manifold. To achieve the desired improve result two other models of same intake manifold with different design configuration are made in software then examine the results of this two models with original one to find out pressure and velocity losses. After analysis of models it noticed that the hidden projections of nut, projected stiffeners and depth cuts o extreme of plenum causes pressure loses due to which uneven distribution takes place at runner's outlets.

Cilj ovog rada je ponuditi pozitivnu argumentaciju direktne demokracije u prilagođenom obliku i bez obzira na njezinu učestalu isključivost u pogledu prevladavajućeg upravnog političkog mehanizma.
U uvodu napominjem kako je pojavnost raznolikih oblika direktne demokracije u svijetu svakako povod dublje razrade tog upravnog oblika. Najavljujem i obogaćenje teorijskog razmatranja detaljnim primjerima vezanima uz oprimjerenje ovog demokratskog oblika za vrijeme blokade Filozofskog fakulteta 2009. godine u Rijeci,
Prvi dio rada sastoji se od određenja diskusijskog okvira kojeg zahvaćam baveći se ovom temom, vodeći računa i da je ona vezana uz povijesni i teorijski okvir koji se uz nju uglavnom veže – poglavito atensku demokraciju i teoriju Jeana Jacquesa Rousseau. Završavam ovaj dio navodeći se određenjem položaja direktne demokracije u političkoj teoriji u pogledu rasprave s predstavničkom demokracijom, s kojom pretpostavljeno stoji u opoziciji.
U drugom se dijelu bavim obranom direktne demokracije na temelju vrijednosti koje ona ispoljava i na kojima bi njeni djelatnici trebali inzistirati da bi bila funkcionalna i poželjna. Od ključnih vrijednosti ističem: deliberaciju, generativnost, građansku aktivnost, hiperproduktivnost, solidarnost, jednakost i informiranost. Naposljetku, branim se i od učestalih prigovora upućenih direktnoj demokraciji, a neke i anticipiram navodeći se pretpostavkama u kojima bi se sve oblicima direktna demokracija mogla pojaviti. Kritike koje detaljno obrađujem su: tiranija većine, apatija građana, grupna polarizacija i dubinska politika.
U završetku se, kao i tijekom rada, osvrćem na potencijalnu sofisticiranost modela direktne demokracije, u slučaju da se navodi predloženim oblikom, a upućujem i na njenu kompatibilnost s predstavničkom demokracijom u širem društvu.