555 Huntington Ave,
Boston, MA 02115
781.522.3000
http://myweb.wit.edu/brouillarde/
August 8, 2011
James R. McCusker
Associate Professor
Department of Mechanical Engineering and Technology
Wentworth Institute of Technology
550 Huntington Ave.
Boston, MA 02115
Dear Professor McCusker:
Enclosed is a copy of The design and build a high efficiency intake for an Audi A4 B7 2.0T. The report focuses on first analyzing the factory air intake system of the Audi, and then designing a more efficient system
that would allow for better air flow as well as cooler inlet air temperatures. It will aid in the further
improvement of the current air intake setup in performance automobile applications.
This report goes through the problems with the current air intakes available. It shows the steps and thought
process taken to design an improved air intake system. Both the new intake system as well as the factory intake
system were tested in the Audi and compared to the results of the factory intake. Using certain parameters from
real world testing, such as outside temperature, the two air intake system were then tested using available
simulation technologies provided to us.
Our results, both through simulation and testing, show that our modified air intake system provides a noticeable
improvement over the factory air intake provided.
We look forward to your review of the report. If you have any questions or concerns please contact us at the
phone number or emails provided.
Sincerely,
Eric Brouillard
Brian Burns
Naeem Khan
John Zalaket
Enclosure: Final Report
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Abstract 1
The Design and Build of a High Efficiency Air Intake
for an Audi A4 B7 2.0T Submitted to: Professor James R. McCusker
Eric Brouillard
Brian Burns
Naeem Khan
John Zalaket
8/8/2011
WENTWORTH INSTITUTE OF TECHNOLOGY
MECH690
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Abstract 2
1.0 Abstract
In this experiment, the objective was to find a viable solution that would resemble the factory intake
system, but would allow a higher flow rate and would be less expensive than the present aftermarket units. This
was accomplished by redesigning the air box to get more capacity, as well as the air intake tube to get better
flow characteristics. During this experiment, a mockup of the designed system was created and tested in the car,
utilizing real world conditions that would allow data for the validation of the results of the new system. A flow
simulation was then conducted using certain parameters from the real world testing, and both the factory air
intake system and the redesigned system were tested. Hand calculations were conducted to ensure that both
results were indeed accurate. After analyzing the results of the real world testing and simulation data, the new
design was indeed more efficient than the factory system.
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Contents 3
2.0 Contents
1.0 Abstract ...................................................................................................................................................................... 2
2.0 Contents ..................................................................................................................................................................... 3
3.0 Introduction ................................................................................................................................................................ 5
4.0 Background Information ............................................................................................................................................ 6
4.1 Modern Automotive Engines .......................................................................................................................... 6
4.2 Air Intake Systems .......................................................................................................................................... 8
5.0 Nomenclature ........................................................................................................................................................... 10
5.1 Greek Letters ................................................................................................................................................. 10
5.2 Subscripts ...................................................................................................................................................... 10
6.0 Methods ................................................................................................................................................................... 11
7.0 Assembly Design ..................................................................................................................................................... 13
8.0 Experimental Procedure ........................................................................................................................................... 19
8.1 Equipment and Materials .............................................................................................................................. 19
8.2 Testing Procedure ......................................................................................................................................... 20
9.0 Results ...................................................................................................................................................................... 21
9.1 Data ............................................................................................................................................................... 21
9.2 Illustration of setup ....................................................................................................................................... 22
9.3 Graphs/Diagrams .......................................................................................................................................... 23
9.4 Sample Calculations ...................................................................................................................................... 25
9.5 Simulation ..................................................................................................................................................... 29
9.6 Discussion of Results .................................................................................................................................... 32
10.0 Final Budget ...................................................................................................................................................... 33
11.0 Conclusions ....................................................................................................................................................... 34
12.0 Works Cited ...................................................................................................................................................... 35
13.0 Appendix ........................................................................................................................................................... 36
13.1 MSDS Sheets ................................................................................................................................................ 37
13.2 Actron User Guide ........................................................................................................................................ 37
13.3 Diagrams ....................................................................................................................................................... 38
13.3.1 Gantt Chart .................................................................................................................................................... 38
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Contents 4
List of Tables and Figures
Figure 1: Otto four-stroke Engine Schematic (Faulkner) ....................................................................................................... 6
Figure 2: Stoichiometric Air/Fuel Ratio Effects (Faulkner) ................................................................................................... 8
Figure 3: Air Flow System for an Internal Combustion Engine (van) .................................................................................... 9
Figure 4: Factory Air Intake System ..................................................................................................................................... 13
Figure 5: Factory Air Filter ................................................................................................................................................... 13
Figure 6: Audi with Factory Intake Removed....................................................................................................................... 14
Figure 7: Mock-Up of Custom Intake ................................................................................................................................... 14
Figure 8: Wireframe of Custom Intake ................................................................................................................................. 15
Figure 9: Wireframe of Custom Air Intake 2 ........................................................................................................................ 15
Figure 10: Air Intake with Fiberglass ................................................................................................................................... 16
Figure 11: Custom Air Intake with Epoxy ............................................................................................................................ 16
Figure 12: Custom Air Intake in Audi .................................................................................................................................. 17
Figure 13: Finished Custom Air Intake ................................................................................................................................. 17
Figure 14: Final Custom Assembly ...................................................................................................................................... 18
Figure 15: Custom Air Intake In Audi .................................................................................................................................. 22
Figure 16: Custom Air Intake Showing Mass Flow Rates .................................................................................................... 30
Figure 17: Factory Air Intake Showing Mass Flow Rates .................................................................................................... 31
Table 1: Decision Matrix for Type of Filter.......................................................................................................................... 12
Table 2: Decision Matrix for Tubing Material ...................................................................................................................... 12
Table 3: Decision Matrix for Housing Material .................................................................................................................... 12
Table 4: Testing Results ........................................................................................................................................................ 21
Table 5: Surface Parameters for Custom Air Intake ............................................................................................................. 32
Table 6: Surface Parameters for Factory Air Intake ............................................................................................................. 32
Table 7: Final Budget ............................................................................................................................................................ 33
Graph 1: Factory Intake vs. Custom for Intake Flow ............................................................................................................ 23
Graph 2: Custom vs. Factory for Temperature ..................................................................................................................... 24
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Introduction 5
3.0 Introduction
The purpose of this project is to create an assembly which will resemble the factory intake system, but will
allow a higher flow rate and cooler inlet air temperatures while also being able to present a final product to the
buyer which is less expensive than the present aftermarket units. For the conceptual design, the plan is to
redesign the air box to maximize area and provide for better flow. A more efficient filter is also used. Then, the
conceptual design was made and tested in the Audi and compared to the factory intake. After testing, the
variables were applied to the 3D model and a simulation utilizing the various real world data was conducted.
This experiment was conducted in accordance with a literature review of previous publications to achieve the
following:
Create the optimum design through SolidWorks
Construct a physical assembly for demonstration
Test assembly with real world conditions
Extract necessary data to satisfy objectives
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Background Information 6
4.0 Background Information
4.1 Modern Automotive Engines
In todays society, the main means of transportation has become the automobile. Its vast variety now
ranges from the original internal combustion engine to hybrids and even full electric powered vehicles. Modern
automobiles have roots originating from the 1860s. This was the time of the first successful internal
combustion engine. The development of these engines has since made advancements that have proved to be
evolutionary. However, the principles of the engine continue to abide by the four-stroke process.
The four-stroke engine means just that; there are four strokes the engine goes through to complete a
cycle which essentially drives a vehicle. The four strokes are: intake, compression, power, and exhaust.
FIGURE 1 below displays the four-stroke cycle from a visual perspective. It displays the relationship between
pressure and volume within the engine cycle. In a naturally aspirated engine there is air at atmospheric pressure
which enters the engine through the air induction system which is described in the following section. (Faulkner)
Figure 1: Otto four-stroke Engine
Schematic (Faulkner)
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Background Information 7
The purpose of this project is mainly focused on the intake stroke of this cycle. It begins with the intake
valve opening allowing air to be transferred into the cylinder while the piston travels down to bottom dead
center Proceeding, the intake stroke is followed by the compression stroke. During this process the piston
moves from the bottom dead center (BDC) to the (TDC). The transfer from BDC to TDC is attributed to the
rotation of the crankshaft and connecting rod, transferring the piston from one end to the other. This stroke
allows for the compression of air within the chamber making it a more dense fluid while adding fuel to the
mixture, in turn optimizing combustion. (Faulkner)
This leads to the third stroke, known as the power stroke. Via a spark plug there is an ignition of the air-
fuel mixture which forces the piston back down to BDC. The resulting effect is the continuing rotation of the
crankshaft and connecting rod and an expansion in fluid volume within the cylinder. Prior to the initiation of the
next cycle the engine goes through the final stroke, the exhaust stroke. The rotational forces attributed to the
crankshaft results in the piston traveling back to TDC and allowing the spent gases to exit from the chamber via
the opening of exhaust valves. (Faulkner)
(Brouillard, Burns and Khan as in Special Topics Report)
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Background Information 8
4.2 Air Intake Systems
During the power stroke, combustion becomes reliant upon the fundamental theories and properties of air
and gasoline. It essentially boils down to the chemistry and ratios between the two. Full combustion requires
14.75 air molecules for every 1 molecule of fuel for optimal performance. Through the electronic control unit of
the vehicle, the ratio of the two are constantly monitored and adjusted to maintain optimal combustion. The
ratio is controlled by the electronic control unit based upon variables such as operating speeds, engine load, etc.
FIGURE 2 below shows the relationship of operating at various air and fuel ratios. (Faulkner)
The introduction of air into the engine is attributed to the air intake system equipped within every vehicle.
This system allows for air to enter the engine directly in naturally aspirated vehicles. However, turbocharged
engines as in this application are fitted with very complex clean-air section with a compressor and aftercooler,
while the intake distributes air to the various cylinders. Supercharged and turbocharged engines have a longer
airflow path than naturally aspirated engines. In engines with a turbocharger, the intake air passes from the
forward module and through the air filter to the compressor located near the exhaust manifold. The compressed
air is then returned to the forward module, where the aftercooler is located. Finally, the clean-air runner
terminates at the intake manifold at the engine. There are three parts to the system, the external air section, the
air filter body, and the clean air section. FIGURE 3, below, depicts the air intake setup. (van)
Figure 2: Stoichiometric Air/Fuel Ratio Effects (Faulkner)
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Background Information 9
Figure 3: Air Flow System for an Internal Combustion Engine (van)
The external air path guides the air into the air filter, while added warm air and helps with the elimination
of dirt. The blending of the warm air affects the engines properties, especially in the cold starting phase. It
also helps in drying the air filter, as well as the melting of snow. Fuel consumption benefits from temperature
regulation for the intake air. Warm air is also drawn in through a second point near the exhaust manifold and is
activated by flaps that are controlled by a thermostat. The external air section also separates coarse particles by
incorporating the use of bends, which allows for minimal pressure loss. This separation keeps the materials
collected at the air filter down and protects against moisture. The next part of the air intake is the air filter body.
This is made up of the filter, the body, and the cover. The body optimizes the airflow path and the air
distribution around the filter. Its main goal is to have the most uniform distribution of air, when it is not
uniform; there is a greater pressure loss at the filter. This results in the efficiency of the engine to decrease.
Also, the more uniform the airflow, the better the filter is able to trap dust and dirt. The clean air channel is the
last part of the air intake system. The MAF sensor, or mass air flow meter, measures the intake air on the clean
side, or output, of the air intake. (van)
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Nomenclature 10
5.0 Nomenclature
Area [ ] Nu Nusselt number
Specific Heat [ ] OD Outer Diameter of tube [ ]
D Diameter [ft] Pr Prandtl number
f Friction Factor Q Flow Rate [ /s]
Convection heat transfer coefficient [ / R] Heat transfer rate [BTU/ s]
ID Inner Diameter of tube [ ] Radius of the tube [ ]
Thermal Conductivity [ ] Re Reynolds number
L Length [ ] Temperature ]
Mass Flow Rate [lbm / s] Thickness [ ]
MAF Mass Air Flow Sensor V Velocity [
5.1 Greek Letters
Surface roughness [ ] Kinematic viscosity
Dynamic viscosity [ Density [ ]
5.2 Subscripts
bm Bulk Mean Outlet conditions
Film s Surface
Inlet conditions surr Surrounding
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Methods 11
6.0 Methods
The following three tables show the decision matrixes that were conducted to make choices regarding the
design of the custom intake. Each matrix had three choices that were considered the best options for the choice
available. The first choice for all the tables, the OEM, was factory for the Audi model. The selection criteria
were based on what was thought to be the four most important factors for the design choice. Some factors, such
as performance and cost, were weighted heavier than others due to objectives set forth at the start of the project.
The ranking for each choice was based on the current information and knowledge available for the various
options. The weights and rankings were based on a one to five scale, five being the best and one being the
worst. The scores were than multiplied and the highest score was the best option for the criteria chosen for the
design. The first table shows the matrix for the type of filter. With the scores weighted, the K&N Round Filter
was the best choice. This was due to its relatively cheap cost, as well as its performance statistics available from
the manufacturer. The second table displays the selection process for the tubing material. Again, the factors of
cost and performance were most important to meet the objectives of the design. With all of the factors, the
silicone material was the best choice for the material. The factory material, interestingly enough, scored the
worst when the analysis was done. The last table was for the housing material. As well as cost and performance,
ease of installation was also an important factor when considering this material. Fiberglass material was the best
choice due to its resistance to heat and its performance in this type of application. Again, the factory OEM
scored the worst.
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Assembly Design 12
Table 1: Decision Matrix for Type of Filter
Filter 1 OEM Flat Paper Panel
Filter 2 Screen Filter
Filter 3 K&N Round Filter
Selection
Criteria
Weights Ranking Weighted
Score
Ranking Weighted
Score
Ranking Weighted
Score
Cost 3 5 15 4 12 4 12
Ease of
Installation
1 2 2 3 3 3 3
Engine Safety 5 5 25 2 10 4 20
Performance 4 1 4 5 20 4 16
Score 46 45 51
Rank 2 3 1
Table 2: Decision Matrix for Tubing Material
Tube Material 1 -
OEM
Tube Material 2 -
Aluminum
Tube Material 3 -
Silicone
Selection
Criteria
Weights Ranking Weighted
Score
Ranking Weighted
Score
Ranking Weighted
Score
Cost 3 3 9 5 15 4 16
Ease of
Installation
2 1 2 3 6 5 10
Thermal
Conductivity
2 3 6 2 4 5 10
Performance 5 2 10 4 20 4 20
Score 27 45 56
Rank 3 2 1
Table 3: Decision Matrix for Housing Material
Housing Material 1 -
OEM
Housing Material 2 Sheet Metal
Housing Material 3 -
Fiberglass
Selection
Criteria
Weights Ranking Weighted
Score
Ranking Weighted
Score
Ranking Weighted
Score
Cost 5 1 5 5 25 4 20
Ease of
Installation
4 2 8 4 16 4 16
Thermal
Conductivity
2 3 6 3 6 4 8
Performance 4 2 8 4 16 5 20
Score 27 63 64
Rank 3 2 1
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Assembly Design 13
7.0 Assembly Design
The arduous task of designing and fabricating the
new intake began with understanding the fundamentals of
how the existing intake was constructed. As shown in
FIGURE 4, the intake is mounted close to the turbocharger
on the passenger side of the engine bay through a ruffled
rubber tube. This tube then connects to the factory MAF
sensor, which is attached to the factory air-box cover via
two screws. Once these parts were removed, there were
only two screws that held the air-box cover to the lower
half of the air-box. When these screws were unfastened, the
air-box cover simply lifted off after unplugging the
connector to the MAF sensor. The wire could then be
unclipped from the lower half of the air-box and moved out
of the way. Now, not only could the factory paper air filter
be removed, displaying one of the core reasons why the
factory intake is so restrictive, but the whole lower section
could be as well.
Although the factory paper air filter was quite large,
a great percentage of the filter is obstructed by baffling,
audible insulation (which does not resist heat), and plastic
shrouds. These obstructions can be seen in FIGURE 5.
Figure 4: Factory Air Intake System
Figure 5: Factory Air Filter
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Assembly Design 14
With all of the factory assembly removed, basic
judgments were made about what useable space is left, as
well as some characteristics of that space. Notice the air
conditioning lines running up the fender-well, and the
catalytic converter coming off the turbocharger in
FIGURE 6. These were two components that had to be
taken into consideration when designing the air-box, so
that the product did not negatively alter the functionality
of the original equipment.
With all of the deconstruction is complete, the
tangible process of designing and building began. Poster-
board was used to represent the intended walls of the
fiberglass air-box. This media was used instead of strictly
metal and fiberglass because it is inexpensive and an easy
material with which to work. With this box mocked up,
realistic dimensions and tangible data were derived, such as
how far the MAF sensor wire could reach, and where to
create mounting locations to secure the box.
The next step in the mock up process was to turn
the thin poster-board specimen into a clean, accurate, and
more rigid box. Then, 1/8th
inch steel rod could be cut to
length for welding into a steel inner skeleton. Each edge
was cut so that it could be measured and drawn out with a
straight edge onto a new piece of poster-board. Having a
one-piece box with straight edges and accurate angles not
only made it much easier to cut lengths of steel for welding,
but it also allowed a SolidWorks drawing to be made so the
casing could be made out of sheet metal if desired. With
the creation of a rigid box, a hole was cut out in order to
estimate the best location for mounting the MAF sensor.
Figure 6: Audi with Factory Intake Removed
Figure 7: Mock-Up of Custom Intake
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Assembly Design 15
Once the 1/8th
inch steel rods were cut to size, MIG
welding commenced. This step required much attention to
detail, because it is quite difficult to weld to such a small
surface. The main issue was that even on the lowest
amperage setting on the welder, the arc would melt through
or vaporize the majority of the material, leaving very little
for the filler rod to mate to. This being said, the process is
possible.
The general structure was tack welded into place
inside the mock-up box. Although the box burnt, all
necessary data was retrieved from it. After these focal
points were secured inside the mock-up box, the two were
removed from the car for final welding. This is where all
the smaller rods were welded in place. They were not all
welded inside the box to avoid a fire hazard, and to better
clamp the mate points for welding. After all the welding
was finished, grinding and sanding took place in order for
the skeleton to have smooth contours.
Now that the final skeleton has been welded up and
test fitted, the fiberglass segment of the build could take
place. The best route of application would be to use a
vacuum bag. Because this item was not readily available,
another mode of application was sought. A woven
fiberglass mat was placed over the underside of the steel
skeleton, which we clipped in place with paperclips. The
clips were then used to help pull the fiberglass tight and in
place for sewing.
Figure 8: Wireframe of Custom Intake
Figure 9: Wireframe of Custom Air Intake 2
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Assembly Design 16
A standard sewing needle and thread was used to
attach the fiberglass to every edge of the steel skeleton.
Once the air-box was fully stitched tightly, multiple coats
of resin and hardener were applied with a brush. We did not
need to leave openings for the MAF sensor and the fender-
well air inlet at this point, because it was easier to cut out of
the rigid air box after the resin and hardener were applied
and solidified.
With the general fiberglass structure finished, the
position needed to be checked once again, and cutouts were
then made with a Dremel tool. The first cutout made was
the hole for the MAF sensor. This was slightly larger than
3.125 inches, and had one 1/8th
inch hole on top and
bottom, which the bolts went through to fasten the MAF
sensor to the box. A piece of vulcanized rubber was then
cut out to fit between the MAF and the fiberglass which
acted as a spacer and gasket.
The next holes were cut to allow air to pass through
the fender-well, as well as to mount the air-box to the
chassis of the vehicle. All mounting holes utilized either
factory hardware, or factory mounting locations. The
bottom two holes acted as the main supports, being held in
by quarter inch lag bolts that were rubber mounted to the
frame. These rubber mounts were chosen in order to
alleviate any stresses that the engine may convey to the
fiberglass due to high torque.
Figure 10: Air Intake with Fiberglass
Figure 11: Custom Air Intake with Epoxy
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Assembly Design 17
Once the box was mounted into position, the MAF
sensor was attached and necessary wires were plugged in to
check proper fitment. Since everything fit according to
plan, the silicone reducer tube was then cut to length. The
trick with this part was not to cut too much off of either
end. Only about 1/8th
inch was taken off every time while
checking fitment. Once the correct length and angle were
established, the clamps were applied to each end to institute
a respectable seal on both the MAF sensor and the
turbocharger inlet.
Since the box was verified to fit both structurally
and functionally, the next step was to find an air filter that
would provide the greatest surface area. Although a custom
built filter through K&N would be ideal, neither time nor
funding permitted this. Ergo, an off-the-shelf K&N
product, was ordered online as it fit the necessary
specifications of the box.
The fiberglass rendered the edges and corners of the
air-box coarse and poor for the desired airflow
characteristics. Therefore, short strand fiberglass filler was
used to fill the low spots and smooth the edges. After being
applied and allowed to sit, the Bondo-Glass was sanded
down before another coat was applied. The process of
applying and sanding was required numerous times until
the surfaces appeared perfectly smooth. These iterations
also aided in firming up the structure of the air-box, making
it appear more rigid than the original plastic box. Again,
tolerances were checked following this phase.
Figure 12: Custom Air Intake in Audi
Figure 13: Finished Custom Air Intake
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Assembly Design 18
The performance assembly was close to
completion, with only 3 major steps to go: Paint, Temp-
Coat, and final installation. A spray-paint was used which
contained preferable thermal properties and could
withstand high heat. This product was evenly sprayed over
the entire air-box surface, to protect the fiberglass, resin,
and bondo-glass from any high heat or poor climate
conditions. Once dried, the adhesive thermal barrier was
cut and applied to the outside of the air-box facing the
turbocharger, catalytic converter, and exhaust downpipe.
Now that all parts have been fabricated and
assembled, it was time to put them all together. First the
MAF sensor was bolted to the air-box, with the vulcanized
rubber washer in place as a spacer in between. The air filter
was then placed onto the MAF sensor inside the air-box,
and secured with the supplied hardware. The silicone
coupler was then secured to the other end of the MAF
sensor, facing down, which utilized an industrial strength
hose clamp. Once this assembly was completed, it was
placed into the open area of the engine bay, in the same
location as the previous factory intake. The open side of the
silicone coupler was attached to the inlet side of the
turbocharger, which used the same style hose clamp
mentioned above. The MAF sensor was reconnected, and
the wire was held in place with two zip ties if necessary.
The final piece was reattached to the factory scoop that
routs the air from the grill to the air filter. Then the only
step remaining was to start the car and check for check
engine lights. None were seen, which suggested this build
was a success.
Figure 14: Final Custom Assembly
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Experimental Procedure 19
8.0 Experimental Procedure
8.1 Equipment and Materials
Posterboard
1/8th inch steel rod
Hose clamp
Hose clamp
Vibrant V32 2714 - Silicone Sleeve
Vibrant V32 2782 - Silicone Elbow
Vibrant V32 2795 - SS T. Bolt Clamp
Vibrant V32 2793 - SS T. Bolt Clamp
Vibrant V32 2173 - Intake Tube
Vibrant V32 12054 - Joiner Tube
Vibrant V32 2175 - 45 Bend Aluminum Pipe
Vibrant V32 2176 - 90 Bend Aluminum Pipe
COOL IT Thermo Tech T19 13575 - Thermo Barrier
COOL IT Thermo Techt T19 14000 - Thermo Shield
DEI D40 010202 - SS. Locking Ties
1/8th inch steel rod
Resin
Fiberglass Matt
Spreaders
Puddy Knife
Foam Brush
Foam Brush
Measuring Cup
Paper Clips
Paper Clips
Brush (3)
Hardener
Spray Paint
Bondo-Glass
Sanding Disks
Bondo-Glass
K&N Air Filter
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Experimental Procedure 20
8.2 Testing Procedure
1. Before performing the following test with the factory intake, a few variables must be noted.
Ambient Outdoor Temperature = ______________________
Weather Conditions (Clear, Rainy, Snow) = _____________
Lighting Conditions (sunny, cloudy, dark) = ______________
2. With the factory air intake in, drive vehicle for 30 minutes on the highway @ 65 mph to simulate
standard driving conditions.
3. After 30 minutes, take the following exit and park vehicle in parking lot and idle for 10 min to allow the
air in the engine bay to reach its highest temperature for the conditions.
4. Begin drive back to starting location on same highway @ 65 mph.
5. After 10 minutes of driving, begin data logging and conduct 3 accelerations at wide open throttle from
1500 rpm to 6000 rpm within 10 minutes of each other. (Note: These accelerations must be done with no
surrounding vehicles present, on a flat, straight section of road, and should not exceed the legal speed
limit at any point.)
6. Save the data to a laptop for analyzing.
7. Return on same route to original destination.
8. Swap the factory air intake out for the custom built performance one.
9. Before performing the following test with the custom performance intake, a few variables must be
noted.
Ambient Outdoor Temperature = ______________________
Weather Conditions (Clear, Rainy, Snow) = _____________
Lighting Conditions (sunny, cloudy, dark) = ______________
10. Repeat Steps 2 through 7 with the only difference being the custom performance intake.
11. Compare and analyze data.
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 21
9.0 Results
9.1 Data
The following data was extracted utilizing the Actron ODB scanner. Following the test procedure, a vast
amount of data was collected and ultimately consolidated into the following table. The focus of the test was to
monitor the two most important variables; mass flow rate and intake air temperature. With these variables, a
comparison between the factory and custom built assembly was possible. The mass flow rate and temperatures
are parameters directly associated to the intake design and its allowable flow.
Table 4: Testing Results
Factory Assembly Custom Assembly
Average
Engine
RPM
Mass
Flow
Rate
(g/sec)
Intake Air
Temperature
( F)
Mass
Flow
Rate
(g/sec)
Intake Air
Temperature
(F)
1482.6 28.7 97.3 28.5 96.0
1549.3 33.1 97.5 34.8 95.5
1751.8 38.9 96.0 41.2 95.5
1868.9 44.4 95.7 46.6 95.0
2019.7 52.9 95.7 58.4 94.0
2189.8 63.2 95.7 73.6 92.7
2594.8 81.1 94.7 83.3 91.7
2781.8 85.6 94.3 88.0 91.0
2964.5 89.1 94.3 92.6 91.0
3162.5 91.3 94.3 96.7 91.0
3347.3 96.0 95.3 100.9 90.3
3533.7 99.6 95.3 106.2 90.3
3711.3 103.2 95.3 111.2 91.0
3918.0 111.7 95.3 119.8 91.0
4239.7 125.4 96.3 128.9 91.7
4431.1 130.1 96.5 137.9 91.7
4599.2 135.4 97.0 145.0 92.3
4875.4 147.5 97.5 151.4 92.3
5026.5 152.5 98.3 158.0 92.3
5243.2 153.9 100.3 160.1 93.3
5408.0 153.6 101.5 160.8 94.7
5567.8 155.7 101.3 160.5 94.7
5745.4 157.9 101.5 162.0 96.3
5968.9 156.2 101.5 161.1 97.3
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 22
9.2 Illustration of setup
The following picture, FIGURE 15, is a top view of the custom assembly installed in the car. Almost all
space was utilized with a secure fitment. From the top, the airbox housing is clearly visible with the filter
installed. On the other side of the wall where the filter is mounted is the silicon tube that leads to the
turbocharger.
Figure 15: Custom Air Intake In Audi
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 23
9.3 Graphs/Diagrams
Through statistical analysis of the raw data acquired through testing, the following graphs were produced.
The first graph displays intake performance while the second graph compares intake air temperatures resulting
from the different assemblies. Three test runs were conducted for each assembly, where mass flow rates and
temperatures were monitored. At similar engine speeds the resulting variables have been plotted, including the
range of data for those particular runs.
The following graph displays mass flow rates within the intake tube at varying engine speeds. The
demand for air is directly proportional to the engine speeds. The two lines are a representation of the intake flow
performance for both assemblies. Overall, it can be seen that the custom assembly allows for a greater flow rate
across the range of engine speeds. The error bars presented display the range of mass flow rates acquired at
those specific engine speeds. As the engine speed increases it can be concluded that the mass flow rate
difference increases attributed to the optimized design.
Graph 1: Factory Intake vs. Custom for Intake Flow
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
1400 1900 2400 2900 3400 3900 4400 4900 5400 5900
Mas
s Fl
ow
Rat
e (
g/se
c)
Engine RPM
Intake Flow Performance
Stock Flow Custom Intake Flow
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 24
The second variable being monitored during testing was intake air temperature. Each point has
temperatures which vary corresponding to the engine speed and mass flow rate captured within that frame.
Overall the general trend displays a decrease in intake air temperature for the custom assembly. With this graph,
the range of values obtained for each engine speed varied slightly more than within the mass flow rates.
Nonetheless, the general trend is clearly defining a decrease in air temperature which is directly associated to
the corresponding mass flow rates.
Graph 2: Custom vs. Factory for Temperature
80.0
85.0
90.0
95.0
100.0
105.0
110.0
1400 1900 2400 2900 3400 3900 4400 4900 5400 5900
Tem
pe
ratu
re (F
)
Engine RPM
Temperature Variation
Stock Intake IAT Custom Intake IAT
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 25
9.4 Sample Calculations
The following calculations were performed to validate results obtained through testing of the custom
assembly. For the following data acquired, an analysis of intake temperatures was conducted. The given
information was utilized to determine the overall heat transfer within the system, and resulting air outlet
temperatures flowing into the turbo. The various equations were acquired from known textbooks, such as
(Cengel).
ENG SPEED RPM 3123
BARO PRS KPA 100
CALC LOAD % 100.0
MAF FLOW GR/SE 100.9
OUT TEMP F 90
IAT F 91
VEH SPEED MPH 45
ABSLT LOAD % 150.0
First, all known conditions and variables were established.
Silicon Tube:
( ) Assume isothermal conditions and neglect thermal resistance within the tube walls
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 26
Prior to performing calculations, the air intake velocity must be adjusted to accommodate the analysis
through the 2.5 section of the tube after being reduced from 3. To do this, a fluid flow rate calculation must be
utilized as follows,
To obtain a velocity, a conversion of mass flow rate to volumetric flow rate is necessary.
(
) (
)
Finally, a velocity is calculated.
(
) (
)
(
)
Flow and temperature parameters:
Since the fluid exit temperature was not a known variable, an assumption was made to determine the
bulk mean temperature ( ) and its properties were used through the process in determining the heat transfer
rate.
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 27
Using the calculated value, temperature properties were acquired.
Temperature 91F
(
)
.07217
(
)
.01505
0.7275
(
)
1.753E-04
(
)
0.2404
(
)
1.265E-05
Next, to determine flow type, Reynolds number (Re) was calculated.
( )
( )
With a turbulent flow and non-smooth pipe, the following relation was used to determine Nusselts
number (Nu) and ultimately the convection heat transfer coefficient (h).
[( )
( ) ]
* ( )
( )+
Being a non-smooth pipe, friction (f) is taken into account and had to be calculated prior to solving for
Nusselts number. This variable is represented as,
(
( )
)
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 28
Giving us,
(
( )
)
(
(
)
)
The friction factor calculated was then substituted into the equation to calculate Nusselts number, and
then the convection heat transfer coefficient.
[(
)
( ) ]
* ( )
( )+
*(
)
( ) +
* (
)
( )+
Initially, an exit temperature of the fluid was not established. Prior to calculating the heat transfer rate,
the exit temperature must be determined and was done so using the equation,
( ) [
]
( )
[(
)( )
( )(
)
]
With all necessary variables previously solved for, the heat transfer rate was then calculated.
( )
( )
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 29
9.5 Simulation
In the figure below, FIGURE 16, a 3D model was created from the dimensions of the newly built
custom air intake assembly. The model consists of the new air box, a skeleton of the air filter, a MAF sensor,
and silicon tube. Then a CFD program within SolidWorks, Flow Simulation, was used to run a flow analysis.
The primary objective of this was to check for flow characteristics, dead spots, and surface parameters at the
end of the silicon tube, which would be the start of the turbocharger.
One of the difficulties while building the model was the air filter. SolidWorks does not have the ability
to do flow analysis through permeable material, so the next best way to test the assembly was to eliminate the
filter material and just create a skeleton to show where the most likely areas of entry into the filter would be.
Another area of difficulty was how to actually evaluate the air box and the best way was to take results from the
actual testing of the real custom air box. Data from the actual testing were inputted into the CFD and this gave
us a fair way to see how the air box would perform.
In the actual testing of the air box in the CFD program a few boundary conditions needed to be satisfied.
The first was an outlet mass flow rate; the mass flow rate chosen was 0.16 kg/s. Next was the environmental
pressure within the air box and this was just the standard air pressure of 101.3 kPa. Then inlet velocities were
chosen with the smaller opening at the top of the air box being 11.2 m/s and the larger side opening at 6.7 m/s
which equaled to 25 mph and 15 mph, respectively. With the boundary conditions satisfied the CFD software
went through its calculations and surface parameters were collected on the face of the lid of the silicon tube.
The resulting data gave us some good numbers to compare with the upcoming simulation of the factory intake,
which can be seen in FIGURE 17.
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 30
Figure 16: Custom Air Intake Showing Mass Flow Rates
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 31
While it was difficult to model the factory intake, this is a fairly accurate representation of the current
factory intake. Within the intake assembly there is the air box, skeleton air filter, MAF sensor, and plastic tube.
Just like in the custom air intake assembly the same CFD software was used to simulate flow characteristics and
collect data. Again the same difficulties that were brought up for the custom intake were consistent for the
factory intake.
In the CFD, testing the same boundary conditions that were used in the custom air intake were used for
the factory assembly. This was to negate any possible variables from skewing the data for both intake
assemblies. Now with the resulting data this allowed us to compare side by side the two air intake assemblies.
Figure 17: Factory Air Intake Showing Mass Flow Rates
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Results 32
9.6 Discussion of Results
With both air intake assemblies done and flow simulations completed the comparison could begin. Since
both of the boundary conditions are the same for the two models the comparison is actually quite simple. Our
main focus was on the exit velocities contacting the lid where the turbocharger would be. Unsurprisingly the
average velocity of the custom air intake was lower than the factory air intake. The custom intake had an
average exit velocity of 30.7 m/s and the factory intake with an average of 34.9 m/s. This suggests that there is a
much smoother and less restrictive flow in the custom when compared to the factory intake. The reason being is
because the factory intake requires higher air velocity to achieve the same mass flow rate of 0.16 kg/s. This
basically means that the engine is working harder to achieve the same mass flow rate. Also another interesting
fact when looking at the surface parameters for the tube lids is the difference in pressure between the two
intakes. The factory intake has a lower pressure than the custom intake. This further proves to the fact that the
engine is working harder because there is stronger vacuum in the factory air box.
One parameter that would be ideally discussed would be the aspect involving the temperature effects, but
because the actual custom air box has many layers of insulation, with some only in certain spots. Also it is
unclear of the exact properties of the factory air intake to even make a comparison that it was decided it was
unrealistic to try and compare the two. The resulting data from the actual testing of the temperatures between
the two air intakes can be seen in TABLE 4 and GRAPH 2. In the table and graph one can see the significant
differences in air temperatures between the two.
Table 5: Surface Parameters for Custom Air Intake
Parameter Minimum Maximum Average Bulk Average Surface Area [m^2]
Pressure [Pa] 100234.1 100659.8 100455.0 100461.4 0.005503591
Density [kg/m^3] 1.2 1.2 1.2 1.2 0.005503591
Velocity [m/s] 29.7 33.8 30.7 30.7 0.005503591
Table 6: Surface Parameters for Factory Air Intake
Parameter Minimum Maximum Average Bulk Average Surface Area [m^2]
Pressure [Pa] 99084.8 99798.9 99551.8 99570.9 0.005503591
Density [kg/m^3] 1.0 1.0 1.0 1.0 0.005503591
Velocity [m/s] 34.0 35.7 34.9 34.7 0.005503591
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Final Budget 33
10.0 Final Budget
Below is the final budget that was needed to accomplish the objectives of this experiment. Not listed in the
budget are the costs of the materials that were already available and did not have to be bought. Certain item
prices were listed in red to denote the fact that they were returned.
Table 7: Final Budget
Place Part Price
Dollar Tree Posterboard 5.00$
1/8th inch steel rod 2.21$
Hose clamp 4.16$
Hose clamp 2.57$
Vibrant V32 2714 - Silicone Sleeve 11.95$
Vibrant V32 2782 - Silicone Elbow 66.95$
Vibrant V32 2795 - SS T. Bolt Clamp 27.90$
Vibrant V32 2793 - SS T. Bolt Clamp 13.95$
Vibrant V32 2173 - Intake Tube 27.95$
Vibrant V32 12054 - Joiner Tube 11.95$
Vibrant V32 2175 - 45 Bend Aluminum Pipe 28.95$
Vibrant V32 2176 - 90 Bend Aluminum Pipe 28.95$
COOL IT Thermo Tech T19 13575 - Thermo Barrier 22.95$
COOL IT Thermo Techt T19 14000 - Thermo Shield 21.95$
DEI D40 010202 - SS. Locking Ties 21.90$
1/8th inch steel rod 23.76$
Resin 14.97$
Fiberglass Matt 6.97$
Spreaders 3.97$
Puddy Knife 11.97$
Foam Brush 0.70$
Foam Brush 0.70$
Measuring Cup 2.97$
Paper Clips 0.88$
Paper Clips 0.88$
Brush (3) 8.91$
Hardener 5.77$
Spray Paint 7.99$
Bondo-Glass 16.99$
Sanding Disks 11.99$
Bondo-Glass 16.99$
www.ourdealsrock.net K&N Air Filter 44.68$
Sub Total = 480.38$
Plus 6.25% sales tax = 510.40$
Total with returns = 350.80$
Each Group Member Owes = 87.70$
AutoZone
Home Depot
Carrisma
Home Depot
Walmart
Home Depot
AutoZone
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Conclusions 34
11.0 Conclusions
After conducting the multiple tests and simulations the data has proven that the new design of the custom
air intake assembly will allow for greater air flow and cooler air inlet temperatures. The overall goal of this
project was to design and build an air intake assembly that could outperform the current factory assembly found
in the 2008 Audi A4 B7 platform. After building, modeling, and testing the new custom air intake assembly it is
safe to say that it does outperform the factory intake. The differences can be seen in the data and graphs in the
report. There is a clear advantage to this new design in that it allows for much smoother flow entering the
engine, adding the ability to increase its air to fuel mixture ratio.
One area that should be looked at it is the materials that we used. While it was acceptable to use the
fiberglass and resin for this one time, there is a most likely a much more suitable plastic that could be used, or
even a sheet metal platform could be employed. A significant amount of research would need to be done to
select a media that could withstand the engine temperatures, vibrations, and the environments within the engine
compartment, as well as provide beneficial thermal properties to benefit the design.
Overall the goal to increase the air flow efficiency and decrease air inlet temperatures was successful. With
this increase of cooler air flow, the engine is able to take in air much easier which allows for greater engine
performance and output. Again with some research the proper materials for the air box can be chosen and a
quality air intake assembly can be made and manufactured to compete with current aftermarket system out for
sale today.
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Works Cited 35
12.0 Works Cited
Brouillard, Eric, et al. Intercooler With R-134a Intergration. Special Topics Final Report. Boston, 2011.
Cengel, Yunus A. Introduction to Thermodynamics and Heat Transfer Second Edition. New York: The McGraw-Hill
Companies, Inc., 2008.
Faulkner, L.L. Applied Combustion, Second Edition. Columbus, Ohio: Taylor & Francais Group, 2007.
Hansen Technologies Corporation. ZEIT4504_Refrigerants. n.d. 28 04 2011
.
Heisler, Heinz. Vehicle and Engine Technology. London, England: Hodder Headline Group, 1999.
Honeywell. Turbo by Garrett. 2010. 28 04 2011 .
Logan, Earl Jr. Handbook of Turbomachinery, Second Edition. New York: Marcel Dekker, 2003.
Mott, Robert L. Applied Fluid Mechanics. Upper Saddle River, NJ: Pearson Education, Inc, 2006.
National Academy of Engineering. Air Conditioning and Refrigeration Timeline. 2011. 28 04 2011
.
National Automobile Dealers Association. NADA Frontpage. 2010. 28 04 2011
.
S H Price. Vapor-Compression Refrigeration. 26 03 2007. 28 04 2011 .
United States Department of Transportation - Federal Highway Administration. Policy Information. 2009. 28 04 2011
.
United States Department of Transportation. Summary of Fuel Economy Performance. 28 October 2010. 28 04 2011
.
van Basshuysen, Richard; Schfer, Fred (2004). Internal Combustion Engine Handbook - Basics, Components, Systems,
and Perspectives. (pp: 240-243). Society of Automotive Engineers, Inc.
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Appendix 36
13.0 Appendix
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Appendix 37
13.1 MSDS Sheets
See attached binder
13.2 Actron User Guide
See attached binder
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Appendix 38
13.3 Diagrams
13.3.1 Gantt Chart
Task Name Duration Start Finish
Conceptual 15 days Mon 5/23/11 Fri 6/10/11
Planning and Control 5 days Mon 5/23/11 Fri 5/27/11
Define project objective and information needs 4 days Mon 5/23/11 Thu 5/26/11
Identify industry standards for project objectives 4 days Mon 5/23/11 Thu 5/26/11
Initial planning complete 4 days Mon 5/23/11 Thu 5/26/11
Develop strategy 5 days Mon 5/23/11 Fri 5/27/11
Discipline Support 10 days Mon 5/30/11 Fri 6/10/11
Start conceptual layout 5 days Mon 5/30/11 Fri 6/3/11
Proposal 0 days Fri 6/3/11 Fri 6/3/11
Complete conceptual layout 6 days Fri 6/3/11 Fri 6/10/11
Proposal Presentation 0 days Tue 6/7/11 Tue 6/7/11
Design 35 days Mon 6/13/11 Fri 7/29/11
Planning and Control 5 days Mon 6/13/11 Fri 6/17/11
Find relevant equations and start calculations 5 days Mon 6/13/11 Fri 6/17/11
Procure equipment 5 days Mon 6/13/11 Fri 6/17/11
Support 10 days Mon 6/13/11 Fri 6/24/11
Start Design 3 days Mon 6/13/11 Wed 6/15/11
Start SolidWorks model 3 days Mon 6/13/11 Wed 6/15/11
Implement first quality review 1 day Wed 6/15/11 Wed 6/15/11
Complete Design 7 days Wed 6/15/11 Thu 6/23/11
Complete SolidWorks model 6 days Wed 6/15/11 Wed 6/22/11
Implement second quality review 1 day Wed 6/22/11 Wed 6/22/11
Design Phase Completion 1 day Thu 6/23/11 Thu 6/23/11
Manufacturing 6 days Fri 6/24/11 Fri 7/1/11
Mid Semester Presentation 0 days Tue 6/28/11 Tue 6/28/11
Construction of Demo 6 days Fri 6/24/11 Fri 7/1/11
Construction Complete 1 day Fri 7/1/11 Fri 7/1/11
Testing 15 days Mon 7/11/11 Fri 7/29/11
Test demo in projects lab 2 days Mon 7/11/11 Tue 7/12/11
Compare with Design and Sample Calculations 10 days Tue 7/12/11 Mon 7/25/11
Project Poster 0 days Tue 7/26/11 Tue 7/26/11
Re-testing based on results 4 days Mon 7/25/11 Thu 7/28/11
Testing Complete 1 day Fri 7/29/11 Fri 7/29/11
Presentations, Final Report, Notebook, Portfolio 0 days Mon 8/8/11 Mon 8/8/11
|The Design and Build of a High Efficiency Air Intake for an Audi A4 B7 2.0T Appendix 39
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