senior final report_audi a4 air intake analysis and design

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

[email protected]

[email protected]

[email protected]

[email protected]

|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 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)


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)


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


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


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


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


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


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


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


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 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


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


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 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


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


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.


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,

(

( )

)


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.

( )

( )


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.


Figure 16: Custom Air Intake Showing Mass Flow Rates


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


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


13.1 MSDS Sheets

See attached binder

13.2 Actron User Guide

See attached binder


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

senior final report_audi a4 air intake analysis and design

Documents

factory air intake system

factory intake system

modified air intake

improved air intake

air intake tube

new intake system

high efficiency air

factory system