New concepts in modeling air filters for internal combustion engines.
Ratiu, Sorin ; Birtok-Baneasa, Corneliu ; Alic, Carmen Inge 等
1. INTRODUCTION
The correct filtration of the air flowing inside the cylinders of
the internal combustion engine is essential for preserving the good
engine's operation in time. The obstruction of various
impurities' admission from the atmospheric air significantly lowers
the wearing-out of the engine's moving parts. Unfortunately, in
addition to its air filtration function, the air filter displays a
significant gas-dynamic resistance of the absorbed air. If the air
filter is not periodically cleaned and the car runs frequently in a
dusty area, both the absorption pressure pa and the filling coefficient
r|V are dramatically decreased (Ratiu & Mihon, 2008).
Currently, on the market there are several constructive air filters
versions, which differ according to the filtering principle:
* filters with filtering cell;
* inertia filters;
* combined filters. These air filters have the following
disadvantages:
* the presence of the filtering element inside the box induces an
enhanced gas-dynamic resistance of the absorbed air (generating the
phenomenon of insufficient absorption);
* storage of impurities inside the filter affects the self-cleaning
feature of the filtering element;
* the filtering element can not be visualized and it has to be
dismantled for the impurity level to be checked;
* incapacity of the air filter to significantly increase the speed
of the absorbed air;
* incapacity of the air filter to cool the absorbed air;
* impossibility of the air filter to create a slight effect of
overfeeding during the functioning of the engine.
2. THE INVERTED SUPER ABSORBING FILTER
The inverted super absorbing filter consists in a cylindrical filtering element, bordered at its front part by an internal diffuser fused to a joint cylinder.
At its rear part, the cylindrical filtering element is embedded
concentric-axially (2/3 of its length) in a mono-block complex, which
consists of an external diffuser for air collection, followed by a
direction-inverter (fig. 1).
For an optimal air collection and absorption yield, the inverted
super absorbing filter is set along the car's geometrical axis
(www.corneliugroup.ro).
[FIGURE 1 OMITTED]
2.1 The external diffuser for air collection with
direction-inverter
Due to its geometry, the external diffuser with direction-inverter
(pos. 1, fig. 1) ensures a very good collection, causing the inversion
of the absorbed air flux by 180[degrees], which is thus directed through
the filtering element towards the internal diffuser (towards the
filter's exit). The external diffuser with direction-inverter
covers the filtering element (pos. 2, fig. 1) (for 2/3 of its length) up
to a very precise distance from the element's exterior, which
ensures the collection and air flux' inversion. Cooling radiators
are located outside the direction-inverter. The cooling radiators
consist of external wings, which cover 80% of the external surface of
the direction-inverter. They maintain a low temperature of the
direction-inverter and generate, consequently, a thermal equilibrium between the surface of the wall and the absorbed air. As result, the air
temperature is significantly decreased before it enters the air filter
(www.corneliugroup.ro).
2.2 The filtering element
The filtering element (pos. 2, fig. 1) has a cylindrical shape. It
consists of a micron-size cardboard, which forms the side surface of the
filtering element (in a radial section, the micron-size cardboard has a
W shape). The cardboard ensures a micron-size filtration and is covered
on the outside with a millimetre sieve, which allows a rough millimetre
size filtration of the air. The micron-size cardboard and the millimetre
sieve are fixed at the two open ends by silicone rings, for an optimal
sealing and concentric-symmetrical alignment with both the internal
diffuser of the front part and the mono-block complex of the rear part.
2.3 The internal diffuser for air acceleration
The internal diffuser for air acceleration has a taper shape and
ensures the connection between the contact surface and the joint
cylinder (pos. 3, fig. 1). Due to its constructive geometry, the
internal diffuser has the capacity to increase the speed of the absorbed
air. Taper-shaped cooling radiators are located outside the internal
diffuser. Because of their taper shape, they redirect the air flux
towards the external diffuser, which allows a concentrated flow of the
air and a minimum gas-dynamic resistance. They maintain a low
temperature of the diffuser and generate, consequently, a thermal
equilibrium between the wall surface and the absorbed air. As result,
the air temperature is significantly decreased before it leaves the
inverted filter. The purpose of the joint cylinder is to link the air
filter to the engine's admission gallery (www.corneliugroup.ro).
The internal diffuser for air acceleration, the filtering element
and the mono-block complex (the external diffuser for air collection
with direction-inverter) have varying dimensions according to the
engine's displacement, so that the bigger the displacement, the
larger the diffuser's dimensions and vice-versa. The inverted super
absorbing filter improves the filling coefficient and is useful for
engines that employ air filters set in the opposite direction of the
absorbed airflow (filters set up at the rear of the Bugatti, Ferrari,
Lamborghini engines).
3. EXPERIMENTAL STAND
The experimental stand consists in making a simplified filter
lay-out. A series of pressure plugs are used, allowing the pressure
field to be determined when the air flows over the filter, highlighting
its capacity of intake and absorption (Alic, 2001). The static pressure
is measured in the external axial collector via the pressure plugs 1, 2,
3, 4, inside the filtering element (at 54 its length) via plug 5, at the
internal diffuser's entrance via plug 6 and inside the joint
cylinder via plug 7 (fig. 2). All these pressure plugs were designed
perpendicular to the airflow. The dynamic pressure is measured at the
basis of the internal cone via plug 8, at the internal diffuser's
exit via plug 9 and at the internal diffuser's external surface via
plug 10 (fig. 2). These pressure plugs were designed axial to the
airflow (Panaitescu & Tcacenco, 2001). The measurements were made
with the digital manometer TESTO 510 (0-100hPa). A significantly higher
collection yield is observed in the presence of the internal cone (fig.
2) compared to when the internal cone is missing.
The following graph shows the effect of the cone's presence or
absence on the recorded pressure fields.
[FIGURE 2 OMITTED]
[FIGURE 3 OMITTED]
4. CONCLUSION
The inverted super absorbing filter has the following advantages:
* being in direct air contact, the filtering element ensures a
minimal gas-dynamic resistance of the absorbed air, therefore increasing
the level of absorption and collection of the air, and consequently
boosting the air filling coefficient of the engine cylinders;
* possibility of the filtering element's self-cleaning;
* the impurities level on the filter can be readily evaluated: the
filtering element can be easily visualized without previously
dismantling the filter;
* the speed of the absorbed air both at the entrance and the exit
of the filter is considerably increased;
* significant capacity of the air filter to cool the absorbed air;
* the air filter creates a slight overfeeding effect during the
engine's operation, which is proportional with the car's
speed;
* this air filter fulfils new tasks, in addition to its classical
function of air filtration: increases the absorption and collection
degree, the speed of the absorbed air, cools down the absorbed air and
inverts the air flux by 180[degrees].
In future, the authors will stress the importance of making
numerical simulations of the air flow through the filter, for different
functioning drives of the thermal engine, both for the urban and outside
town traffic. Future studies will focus on making efficient the air flow
process through the filter and will be made by "computational fluid
dynamics" methods. Also, the aim is to prove by experimental
measurements the air's intake effect, and the results will be
compared with the ones obtained by numerical methods.
Note:
This article is based on an original idea of author Birtok-Baneasa
Corneliu, appreciated in time as follows:
1. Silver Medal at the "37-th International Exhibition of
Inventions, New Techniques and Products" Geneva 04.2009, for the
invention "Inverted super absorbing filter";
2. Special Award at the "Salon of invention and creative youth
research", Bucharest 11.2008 for the paper "Dynamic System of
Air Transfer";
3. Gold Medal at "The International Eureka Contest
Brussels", 11.2008;
4. Gold Medal at "The International Salon of inventions and
new technologies Inventika", Bucharest 10.2008 for the invention
"Inverted Super Absorbing Filter";
5. Invention patent. Author--Birtok-Baneasa, C.: INVERTED SUPER
ABSORBING FILTER
Patent demand: A/00350 / 12.05.2009, Class: P Application in auto
industry.
5. REFERENCES
Alic, C. (2001). Experimental research basis--Theory elements and
applications, "Orizonturi Universitare" Publishing House, ISBN 973-8109-43-4, Timisoara, Romania
Cioata, V.G. & Miklos, I.Z. (2009). Computer-assisted designing
with Autodesk Inventor, "Mirton" Publishing House, ISBN
978-973-52-0576-8, Timisoara, Romania
Panaitescu, P. & Tcacenco, V. (2001). Fluids mechanics'
basis, "Technical" Publishing House, ISBN 973-31-2054-5,
Bucharest, Romania
Ratiu, S. & Mihon, L. (2008). Internal combustion engines for
road vehicles. Processes and Characteristics, "Mirton"
Publishing House, ISBN 978-973-52-0314-6,Timisoara, Romania
*** http://www.corneliugroup.ro-Accessed: 2009-03-18