Lightweight Transmission Mount Design

1.1 Mechanical Powertrain Department Final Report
Date: 12/10/2018
Authors Contact Information
Abhinit Kothari aak5408@psu.edu
Authors Contact Information
Nate Stauffer nqs5118@psu.edu

1
Executive Summary
The Penn State Advanced Vehicle team is split up into five different departments: powertrain,
chassis, electrical, ADAS, and controls. As the powertrain team we have been responsible for the
major components that make up the powertrain such as the engine and transmission but also worked
on smaller tasks to improve our hybrid electric Chevrolet Camaro.
Over the semester the team focused on accomplishing milestones established early on. The oil pan
was leaking at the beginning of the semester so this needed addressing and was accomplished. The
engine mounts cracked last year during competition so they needed to be fixed which was
completed. The transmission mount was light weighted where material was not necessary. Last year
the engine was using a coned air filter which was replaced with the stock air box for improved air
intake. The throttle body intake was also designed to be replaced for aesthetics. The thermal system
was ensured to not be leaking as it was in the beginning of the semester. And lastly the trunk cover
for the ESS was light weighted and improved to maximize the trunk space.
With a project on this big of a scale a Gantt chart was required to complete tasks in a timely manner
which is discussed in detail later. As a team the budget was much lower than in previous years due to
no major components needing to be purchased. The team was able to stick to the risk plan well with
no major deviations from it besides falling behind schedule at times.

2
Table of Contents
1.1 Mechanical Powertrain Department Final Report.................................................................. 1
Executive Summary.............................................................................................................................. 1
Table of Contents.................................................................................................................................. 2
1.0 Introduction................................................................................................................................ 3
2.0 Detailed Design.......................................................................................................................... 3
2.1.1 Transmission Mount..................................................................................................... 3
2.2 CAD Models and Drawings ................................................................................................... 4
2.3 Material and Material Selection Process................................................................................ 6
2.4 Design Analysis...................................................................................................................... 7
3.0 Manufacturing Process............................................................................................................... 8
3.1 Transmission Mount............................................................................................................... 8
4.0 Test Results and Discussion..................................................................................................... 10
4.1 Transmission Mount............................................................................................................. 10
5.0 Customer Needs Self-Assessment (Design Criteria Satisfaction) ........................................... 10
6.0 Project Management Summary................................................................................................ 13
6.1 Project schedule.................................................................................................................... 13
6.2 Economic Analyses - Budget and Vendor Purchase Information........................................ 14
6.3 Risk Plan and Safety ............................................................................................................ 15
7.0 Conclusions and Recommendations ........................................................................................ 16
8.0 References................................................................................................................................ 17
Appendix............................................................................................................................................. 18

3
1.0 Introduction
The powertrain team’s main goals were to research about the car and propose plans to solve the
problems faced by the car in the previous years. The team’s long-term goal is to free the Chevrolet
Camaro from all its problems. The team members had tasks initially assigned to them that were to be
completed and have the vehicle functional by the end of the semester. The team’s main priority was
to make sure to meet the customer needs throughout the duration of the project. In the beginning of
the semester the team was responsible for fixing the oil pan leakage, modifying the engine mounts,
redesigning the transmission mount, replacing the air filter, and fixing the leakages in the thermal
coolant system. Various problems faced by the team while solving these tasks will be discussed in
this report.
The team also decided to improve the aesthetics of the energy storage system (ESS) area and address
the throttle body intake since the submission of the proposal. These tasks have been assigned to
improve the performance and efficiency of the vehicle.
2.0 Detailed Design
2.1.1 Transmission Mount
For the transmission mount to meet required technical specifications from the customer it must be
reliable, lightweight, and not decrease the vehicle lifetime. To ensure that the transmission mount is
reliable during vehicle operation it must be able to withstand the static load from the powertrain as
well as hypothetical GM loading conditions. To ensure reliability the transmission base plate is made
from the proper material that has the appropriate mechanical properties to withstand the required
loading. The design also has the appropriate geometry that can withstand the various loadings it may
experience. To contribute to the vehicle being lightweight the transmission mount was made as light
as possible. To accomplish this, material was removed from the base plate where it was not
necessary and did not significantly contribute to the overall strength of the mount. A material that
was lightweight while also maintaining the necessary mechanical properties was implemented into
the design as well. With vehicle lifetime being very important there are a few features that were
incorporated into the transmission mount design to ensure it did not negatively affect this
specification. There were two locations on the original mount base plate that there was interference
with other components on the vehicle. These interferences were mitigated in the new design of the
transmission mount base plate. The transmission mount was designed with these technical
specifications leading the process and is detailed in section 2.2.1 and 2.3.1.

4
2.2 CAD Models and Drawings
The full transmission mount assembly consists of multiple components to help support the
transmission as well stabilize it and reduce vibrations during vehicle operation. In Figure 6 the entire
assembly of the transmission mount can be seen with the various components labelled. The
components of the transmission mount assembly include a baseplate, vibration absorber and
transmission mount plate. The baseplate is the means for attaching the transmission mount to the
vehicle, the vibration absorber mitigates any vibration from the transmission and the transmission
mount plate is where the transmission mount attaches to the transmission itself.
Figure 1. Assembly of transmission mount that is currently on the
vehicle

5
The focus for the transmission mount design was to reduce the weight of the base plate as this was
the component with the most light-weighting potential. The first step to achieving this was to select
the appropriate material. For the transmission base plate aluminium 6061-T6 was chosen for its
lightweight characteristics and mechanical properties which will be discussed more in section 2.3.
The baseplate design in Figure 7 and Figure 8 utilizes material removal to light weight as well to
mitigate the interferences of the current mount. In Figure 8 two cut-outs can be seen that were
specifically designed to mitigate interference that was present with the transmission shifter cable as
well as transmission bolts on the previous transmission mount base plate (marked with red arrow).
If the bolts on the transmission consistently hit the base plate it creates vibration and over time can
cause damage to the transmission itself. If the transmission shifter cable interferes with the mount it
has potential to fail overtime due to severing as well as being pinched. With these possible outcomes
it was imperative that these interferences be mitigated in the new design. The remaining cut-outs on
the base are strictly for light weighting purposes. Anywhere that material was removed was done so
because minimal stress was seen in those areas as determined by FEA which will be discussed in
section 2.4.1. The baseplate was designed as a direct fit so no further modifications needed to be
done for it to fit on the vehicle.
Figure 2. Isometric view of the transmission mount base plate design

6
2.3 Material and Material Selection Process
The redesigned transmission mount is made completely out of aluminium 6061-T6. When designing
the mount, mainly the base plate, there were three possible materials that were considered to help aid
the light weighting efforts: aluminium 6061-T6, magnesium, and titanium. The previous mount that
was on the vehicle was aluminium 6061-T6 so the two other material options were compared to that
to determine if making the material switch was justifiable. To determine which material would be
best for our application the pros and cons of each had to be weighed. While titanium is 2x stronger
than aluminium it is also 60% heavier and approximately 8x more expensive. Weight savings could
be made with this material, but the same could be done with aluminium at a cheaper cost. Using
titanium was not a justifiable switch. Using magnesium seemed to be the best route other than
aluminium as it is 33% lighter than aluminium and has roughly the same mechanical properties.
Magnesium is also being used more and more in the automotive industry as a way of light weighting
components that are typically aluminium. The issue with magnesium was that it was also 8x more
expensive than that of aluminium. The cost of using magnesium was not justifiable for this
application. Magnesium and titanium companies were both contacted for a possible material
donation, but the inquiries were unsuccessful.
Figure 3. Interference areas that were taken into design consideration

7
Aluminium 6061-T6 has a minimum yield stress of 240 MPa which is more than enough for this
application and will be verified in section 2.4. This material is also lightweight and corrosion-
resistant, both of which are very important characteristics for use on a vehicle. With the previous
pros and cons weighed and mechanical properties evaluated it was clear choice that aluminium
6061-T6 would be the material used for the new transmission mount design
2.4 Design Analysis
In previous years, students had worked on creating a design for possible light-weighting of the
transmission mount. It was decided to lightweight the current mount by developing a design with
cut-outs in areas of low stresses on the base plate. This design involved multiple cut-outs in sections
of low stresses that were determined by running a FEA on the mount. Since light weighting involves
introducing new stresses to the mount, exact loading conditions were needed so a FEA could be ran.
A free body diagram was made that included the transmission mount, motor and motor housing, and
the engine mount. The loading conditions on the transmission mount were calculated from the free
body diagram by taking sum of the moments about the engine mount to find the force acting on the
transmission mount. This force was then multiplied by the GM specified 8Gs and 20Gs loading
conditions to get the vertical and horizontal force on the mount, respectively. The picture of the free
body diagram and the calculation is shown in the Appendix, Figure 32 and Figure 33 respectively.
Figure 4. FEA on the modified transmission mount under downward vertical loading.

8
FEA was then ran on the base plate and the stress results can be seen in Figure 25 for the downward
vertical case. The remaining five loading conditions FEA’s (upward vertical, left lateral, right lateral,
forward lateral, and backward lateral) can be found in the Appendix in Figure 34, Figure 35, Figure
36, Figure 37, & Figure 38. The vertical loading conditions proved to show much higher stresses
then that of the lateral directions, so these loading conditions were given priority in terms of
determining design. As can be seen in Figure 25 all of the stress is under the minimum yield stress of
aluminium 240 MPa as well as with a 1.5 safety factor applied. This means that with the safety
factor applied all stress are under 160 MPa. The only location that technically was over the yield
stress of aluminium according to the FEA results was the upper bolt holes. This is due to the
constraint that was applied to them to simulate the mount being attached to the vehicle. A fixed
constraint was applied, but this approach is very conservative considering this area is not truly fixed.
It was determined that the results at this location were an exaggeration of the actual stress this area
would experience. The FEA results for the transmission mount base plate validate the design and the
stresses on it based on the loading conditions applied.
Another way of validating the FEA was done through hand calculations to determine the average
stress on the base plate under vertical loading. Based on the free body diagram and hand calculations
in Appendix and Figure 32 & Figure 33, the vertical force on the base plate is 7400 N. Using
Siemens NX, the area of the modified base plate was determined to be 45,975 mm2
. Based on these
values, the average stress over the entire plate was calculated by using the equation; Stress =
Force/Area. In this case, the value of the stress is 0.16 MPa. This value when compared to the FEA
shown in Figure 25 demonstrates that the design is valid and that the FEA results are verified
through hand calculation. However, the FEA shows that the average stress in blue and the maximum
stress around the bolts is much higher than 0.16 MPa. This is mainly due to the application of a fixed
constraint while conducting FEA. In addition to this, the dark blue areas of stress on the FEA are
within the 0.16 MPa range which validate the design. The only areas with extremely high stress are
the bolt holes which is affect by the fixed constraint. Also, the 0.16 MPa is a value that demonstrates
the average or profile stress across the whole base plate considering the bolt holes and the areas of
low stresses. The areas of low stresses are more prominent thereby resulting in a value of 0.16 MPa.
3.0 Manufacturing Process
3.1 Transmission Mount
After a light weighted design for the base plate was generated a manufacturing plan had to be made
to implement the design on the vehicle. Since the final design had a lot of cut-outs in terms of holes
and edges, two manufacturing processes were taken into consideration; water-jetting and milling. In
the case of water-jetting, the base plate design was taken to the learning factory to figure out the cost
of the water-jetting. The plan was to buy was a new Aluminium 6061-T6 plate and water-jet it to
create a completely new mount. However, the cost of water-jetting and buying a new plate was
around $125 which was expensive considering the weight savings would not be higher with water-

9
jetting when compared to milling. Hence, milling was finally decided as the manufacturing process
because it costs $0 and it can be performed in the garage reducing the downtime on the vehicle. To
make the manufacturing easier for the cut-outs, all circle radii for the cut-outs was set at 0.375”. This
number was chosen since a 0.75” end mill was bought, and this would allow the team to use the
same end mill for all material removal. A detailed manufacturing plan was generated in order to
make the milling process effective and can be seen in Figure 26. A to-scale pattern was also printed
out to show the locations of the cut-outs to provide a sanity check when machining as well as to
provide a pattern for the material removed on the lower mounting legs. The manufacturing process
took about 4 hours and the mount was successfully machined with the cut-outs and different
geometry. Figure 27 demonstrates the machining process that was implemented. The modified
transmission mount weighed at 1.50 kg which is 1 kg lighter than before machining. The light-
weighting and the manufacturing processes were successful in terms of light-weighting the
transmission mount and the vehicle as a whole.
Figure 5. Manufacturing plan used for machining the existing
transmission mount

10
4.0 Test Results and Discussion
4.1 Transmission Mount
There was no specific test preformed once the transmission mount was placed on the vehicle other
than to ensure proper fitment. The transmission mount utilized FEA as described in section 2.4.1 to
test the design before proceeding with manufacturing.
5.0 Customer Needs Self-Assessment (Design Criteria Satisfaction)
Over the course of the semester the powertrain team had quite a few customer needs as a department.
These needs have not been modified since the proposal as the powertrain department was striving to
meet all of them for the entirety of the project. There was a whole list of customer needs that the
powertrain team needed to meet this semester for our project including: fuel efficient, safe, cost,
timely completion, reliable, good sponsor representation, performance, no oil leakages, no thermal
leakages, light transmission mount, and better performing airbox. In Table 1 all the customer needs
have been assessed on a scale from 1-10 based on if they have been met or not. In the following
paragraphs the reasons for each rating for each customer need with be justified as they pertain to the
powertrain projects that were worked on during the semester and the project deliverables will be
evaluated for completion.
Figure 6. Manufacturing the transmission mount on the mill in the garage

11
Table 1. Self-assessment of customer needs
Customer Need Rating
Fuel-Efficient 10
Safe 10
Cost 10
Timely Completion 7
Reliable 9
Good Sponsor Representation 10
Performance 7
No Oil Leakages 10
No Thermal Leakages 10
Light Transmission Mount 9
Better Performing Airbox 8
Average Rating 9.09
Overall, the powertrain team did well with meeting the customer needs determined in the beginning
of the semester with an average rating of 9.09. As expected, there were still shortcomings that led to
not having a perfect 10 rating.

12
The fuel-efficient customer need was fully satisfied as many components that were worked on
helped to improve the overall fuel efficiency of the vehicle. The transmission mount and ESS cover
reduced the overall weight of the vehicle and the airbox was improved which positively contributed
to fuel efficiency.
The safe customer need earned a 10 rating as well since every project that was worked on for the
powertrain team had safety as a top priority. Each design that was implemented was assured to be
safe for operation by making sure the proper precautions were taken such as testing and FEA.
The cost customer need earned a rating of 10 as very minimal money was spent during the semester.
The transmission mount light weighting and fixing of the engine mounts did not cost the team any
money. The ESS improvements, fixing of the oil pan leakage, and throttle body pipe improvements
cost minimal money with the purchase of a few cheap components.
The timely completion customer need received a rating of 7 as some of the projects were not
completed by the end of the semester. The engine mount redesign, oil pan modification and throttle
body hose improvement ran in to various drawbacks that caused them to have to be completed in
future semesters. On the other hand, the transmission mount light-weighting, engine mount fix, ESS
cover, oil and thermal leakages, and improved airbox were completed this semester and in a timely
fashion.
The reliable customer need was given a score of 9 since all the projects completed were determined
reliable with exception of the airbox improvements. The airbox had to utilize duct tape to eliminate a
gap in the inlet which is more of a temporary fix as opposed to a long-term solution. The
transmission mount implemented specific design features to ensure that it remained reliable as well
as mitigating reliability issues it previously caused with components around it. The oil pan
modification, engine mounts, and ESS covers were all designed to assure they were reliable
solutions.
Good sponsorship representation received a rating of 10 as the projects competed made sure to
represent the sponsors as best as possible and the funds donated were used appropriately to improve
upon the vehicle.
The performance of the vehicle received a rating of 7 for various reasons. As discussed previously
the inlet gap in the airbox was covered with duct tape which is not ideal for the intake system to
perform optimally. The modification of the vehicle cross member to fit the stock oil pan in the
vehicle was not completed which affects to overall performance of the vehicle as it would perform
better with the stock oil pan. The transmission mount and ESS cover being light-weighted however
did positively affect the performance of the vehicle.
Since the oil pan leakage and thermal leakages were fixed during the semester, both customer needs
received a rating of 10. The customer needs to have a light transmission received a score of 9. While
the transmission mount was able to reduce the weight of the vehicle by 1 kg, the weight could be

13
reduced even more with a completely new design using different engineering techniques. While the
airbox performance was improved during the semester, it received a rating of 8 due to temporary
solutions being applied to mitigate leakages in the system.
The intended project deliverables in the beginning of the semester included the engine mounts being
fixed, the transmission mount being lighter, a better performing airbox, fixing the oil pan leakage
and fixing the thermal leakages. All these project deliverables were met while also completing
additional deliverables such as a better ESS cover. Tasks such as redesigning the engine mounts,
improving the throttle body hose and modifying the vehicle cross member to fit the stock oil pan
were added during the semester and were not met but the ground work for future semesters to
continue them was completed.
Overall, the powertrain team was successful in meeting most of the customer needs and completing
the project deliverables that were determined in the beginning of the semester.
6.0 Project Management Summary
To keep the team on track for the semester a Gantt chart was used to map out the tasks that would be
required to finish the milestones. A budget and bill of materials were created to keep the project
within financial limits and so other teams can know the parts we used. Finally, a risk plan was
developed to keep the project safe and have actions in case things went wrong.
6.1 Project schedule
The powertrain team broke down their responsibilities into seven different milestones to be
completed. Each of these milestones had smaller tasks with a team member responsible for the
completion of this task. A portion of the Gantt chart can be seen in Figure 7 with the oil pan task
expanded to show a sample of tasks that go into a milestone.

14
Figure 7: A view of the teams Gantt chart used this semester. The oil pan section is open to show an
example of tasks for each milestone.
Some of the milestones for the semester ran into unforeseen obstacles such as errors when trying to
run FEA on assemblies. To overcome these setbacks tasks were adjusted to make sure team
members were being as productive as they can be. Some tasks were not able to be completed this
semester but with a project on such a big scale and so many team members it is hard to avoid this.
Overall the team was successful in completing tasks to improve the Camaro and learning a lot along
the way.
6.2 Economic Analyses - Budget and Vendor Purchase Information
Table 2. Powertrain team budget
Budget
Category Cost($)
Transmission Mount 33.50
Oil Pan 40.69
Total Spending 74.19
Above, in Table 2 is the budget of all the money that the powertrain team used this semester in order
to accomplish the team’s goals. It clearly states exactly what the team spent and how much was
spent this semester by the team. All the money used was used properly and only for the betterment
of the team as a whole.

15
Table 3. Powertrain team BOM
Bill of Materials
Product Quantity
¾” HSS End Mill 1
Permatex Ultra Black
Gasket Maker
1
M8 helicoil kit 1
Above, in Table 3 is the Bill of Materials (BOM) for the powertrain team in year 5. This BOM states
exactly what products were used and the quantity used of that product. This table is useful for teams
in the future to see exactly what this year’s team used so that they will know what is new and what is
old on the Camaro.
6.3 Risk Plan and Safety
The powertrain team did its best this semester to avoid any of the risks that the team had worried
about in the beginning of the semester. However, there were some risks that occurred. One of the big
risks that occurred was schedule delays. This tried to be managed by the team to the best of their
abilities, but ultimately there were schedule delays that set the team back as a whole and in some
cases caused projects to not be finished. Specifically, there were delays in when work was finished
for the engine mounts and cross member modification that caused everything to be backed up. The
other big risk that occurred this semester was oil pan leaks. The team tried to avoid any leaking of
the oil pan by starting early but further complications had caused a leak to occur on the oil pan after
the initial solution was performed. Ultimately, though the oil pan was finally fixed, but the risk is
still high that it could leak again due to the limited amount of testing that was done to assure its
solution.
As a team there was a new risk that occurred throughout this semester. The one new risk that
occurred was the possibility that hot air may still enter the airbox from the engine bay because of
low quality seal using duct tape. This risk could cause poor combustion and therefore poor emission
quality. This risk is low but none the less there is still a risk. The way to counteract this risk would
be to either create a new airbox with a secure cold air duct seal or modify the cold air duct so that it
tightly seals to the airbox. Next, one way to counteract the schedule delay risks is to map out
everything that needs to get done at the beginning of the semester. By doing this the future team
could allocate extra time to areas of uncertainty in the project so there is enough time to figure out

16
the issues. Lastly, to counteract the oil pan leaks the team could do a lot of actual testing by putting
miles on the Camaro and checking for leaks. This would show the actual leak locations and would be
easier to determine where exactly the leaks are occurring. The team this semester had to go off of the
leak locations just from the car sitting still due to the fact that the Camaro didn’t run all the time.
That caused a lot of guessing to occur where the actual leaks were coming from which could be
avoided next semester.
7.0 Conclusions and Recommendations
From the aspect of the powertrain department, this project allowed the team to address the problems
that were determined at the start of the semester. Most of the goals were addressed in such a manner
that either the task was completed, or it was completed to an extent that the next team to take over
can ease into the task. The main goal with every design was to address the customer needs that were
determined in the proposal report. A lot of these goals were met to a good extent.
In the terms of the transmission mount, all the customer needs were met successfully, and the mount
was redesigned. The process of redesigning and manufacturing had some roadblocks especially in
terms of getting FEA to work. The manufacturing of the new design resulted in a 1kg weight
reduction in the mount. In terms of future ideas for working on the transmission mount, light
weighting the current mount does not have much scope. The team could focus on designing a new
mount that employs “ribs”. The introduction of ribs into a design can reduce the weight while
minimally negatively affecting stress concentrations in certain areas.
For the throttle body hose, there was research done on how to purchase the hose to increase the
aesthetics of the vehicle, avoid contact and light weight the part to increase the efficiency of the
vehicle. The proposed solution was to replace the current steel hose with an aluminium one to reduce
weight and increase the aesthetics. Purchasing the hose with the right dimension and bend radius
could avoid contact with the radiator fan. The team was not able to get the required specifications
from the manufacturing company and as a result the purchased part did not fit the vehicle. The part
can be machined to fit the vehicle along with some additional parts. This is a good area to look into
for the future team.
The oil pan is not currently leaking on the vehicle, but improvements can definitely be made to make
a more robust design and improve the aesthetics. There was significant work put into a design to
modify the cross member and put the stock oil pan back on the engine. The team recommends to
pick up on this work and complete the task of installing the stock oil pan back on the vehicle. The
FEA model for the front cradle has proven to be very difficult but is solvable with enough hard work
and dedication.

17
8.0 References
Fabric to Plastic. (2018). Retrieved from this TO that: http://thistothat.com/cgi-
bin/glue.cgi?lang=en&this=Fabric&that=Plastic
Aluminum Pipe. (2018). Retrieved from http://www.siliconeintakes.com/aluminum-
pipes/aluminum-pipe-p-292.html

18
Appendix
Free Body Diagram for the Transmission Mount
Figure 8. Free Body Diagram that was used to determine the loading conditions to run FEA
on the base plate
Figure 9. Hand calculations done to calculate the force on the transmission mount

19
Finite Element Analysis results in all directions for the transmission mount base plate
Figure 10. FEA in the lateral direction from the back Figure 11. FEA in the lateral direction from the front
Figure 12. FEA in the lateral direction from the left Figure 13. FEA in the lateral direction from the right
Figure 14. FEA in the vertical up direction

Lightweight Transmission Mount Design

Recommandé

Recommandé

Contenu connexe

Similaire à Lightweight Transmission Mount Design

Similaire à Lightweight Transmission Mount Design (20)

Dernier

Dernier (20)

Lightweight Transmission Mount Design