Team Tennessee’s Torque Neutral Engine

Team Tennessee’s vehicle design is very specific, and every component is crucial for the plug-in hybrid electric vehicle (PHEV) to run properly. This includes the torque neutral engine and transmission mounts, which consist of metal plates bonded to rubber.  These mounts are responsible for absorbing the vibrational impacts caused by the operation of the engine and transmission and minimizing the vibrations detectable by the occupants. The mounts were modeled and modified to account for the translational movement of the engine and transmission and to fit the generator within the tight constraints of the engine bay.

The torque neutral transmission mount was shifted 23mm towards the driver’s side of the vehicle.  In order to accomplish this task, the bottom surface of the stock mount was milled down by ½” to allow the fitment of an adapter plate.  The adapter plate was modeled and analyzed using UGS NX CAD software.  The adapter plate will consist of three through-holes for bolting the plate to the transmission, as well as three tapped holes for bolting the original mount to the plate.  The adapter plate design allows the elastomeric portion of the mount to be retained in its original form.  The original mount was assumed to be constructed of Aluminum 6061, while the adapter plate was AISI Steel 4340 due to its high yield strength.

stock and modified torque

Stock and Modified Torque – Neutral Transmission Mount

The torque neutral engine mount was completely redesigned to accommodate another 18mm offset of the engine in the direction of the passenger side of the vehicle.  The UGS NX CAD software was also used to redesign and analyze the torque neutral engine mount and connecting mount to account for the offset and clearance issues from the engine block.  These components were constructed of Aluminum 6061 and Rolled Steel, for the new engine mount and connecting mount, respectively.

Stock and Replacement Torque - Neutral Engine Mounts

Stock and Replacement Torque – Neutral Engine Mounts

Finite Element Analysis (FEA) and simulations were performed in three separate load cases for each of the modified components, then compared to the stock specifications.  A safety factor of two over the original mount was a main requirement for the waiver process.  The load cases consisted of a 20g fore/aft load, 20g lateral load, and 8g vertical load to represent the event of a collision.

With the completion of these components, the generator was able to fit within the engine bay without fitment issues.  Just before the Year Two competition, the team performed a series of mock ups to ensure an effortless installation of the generator. Now looking ahead to Year Three, the team will begin to refine their vehicle, including the design to the generator and torque neutral engine and transmission mounts.