THE 1997 JEEP TJ
Relectric is currently working on a new conversion project, the 1997 Jeep TJ! Adding a new EV system to the jeep, Relectric is giving new life to a once unsustainable vehicle, taking steps to streamline EV conversions !
SUBTEAM TECHNICAL FEATURES
MECHANICAL
The mechanical sub team primarily deals with the drivetrain of the Jeep; the connections between the motor and the transmission and the process of mounting these components to the chassis. The HyPer 9 Model EV Motor provides rotational power to the transmission through its output shaft. The output shaft of the motor is coupled to the input shaft of the transmission through a shaft coupling. This coupling is currently in the process of being custom designed. The design is based on the current flywheel and clutch, which act as the actual connection between the motor and the transmission.
The Hyper 9 EV motor requires a custom adapter assembly to fit in the original location of old engine - to properly connect to the transmission. This adapter assembly is currently in the design phase - its current concept involves a mounting bar that connects on either side of the chassis, through the drivetrain region. A motor cradle will sit on top of this mounting bar, with correct positioning relative to the transmission, in order to safely secure the motor.
The flywheel bolts to the shaft coupling while the clutch assembly bolts to the flywheel. The clutch assembly consists of the clutch, which is directly connected to the transmission output shaft, and pressure plates, which clench and release the clutch from the flywheel. The original Jeep engine was mounted on motor mounts, which were bolted directly on the Jeep’s chassis through built-in brackets. These motor mounts are in the process of being replaced, as the original ones were quite worn down.
ELECTRICAL
Batteries store chemical energy that can be converted to electrical energy (discharging) or visa versa (charging). To control when we allow batteries to charge or discharge, we use contactors. These allow us to control a high voltage system with low voltage (12v) signals. When allowed, we have distribution for HV+ and HV- that connects it to our loads such as the charger, DCDC and inverter. The charger converts AC electricity from the grid to the DC voltage needed to charge the batteries through rectification. The DCDC converter steps down the 110v from batt to 12v used to power the low voltage loads like VCU (vehicle control unit), rad pump, rad fan, Jeep lights and loads.
The final element is the control scheme- we use CAN (controller area network). Which is a 2 wire system that writes the differential (1 or 0). It is very noise resistant and allows nodes to communicate on a common bus with 60ohm across (impedance matching). They use an arbitration process, basically they just put something on the bus to say "I have something to say" and a priority (" I have something more important to say ") and the highest priority wins and sends its message then the process repeats.
The inverter is the powerhouse and is most of our load - it uses the DC voltage and switches it to AC to power a synchronous reluctance internal permanent magnet motor (SRIPM). It does this in a very controlled way and by varying the current supplied to the motor it can vary the magnetic field spinning the rotor and thus vary the speed. We then take this rotation and run it through our drivetrain to spin tires, or in the case of regen use the spinning of the tires to reverse the spin of the motor, thus inducing a current back to the inverter that gets rectified and used to re-charge the batteries while braking
INTERIOR
Interior's main project is programming and implementing a graphical user interface for the Jeep's user to interact with while operating the vehicle. The graphical user interface (GUI) will run on a touchscreen mounted to the Jeep's dashboard, and will allow the user to fully interact with the systems of the car. The GUI program itself is built using libraries in python, and has allowed Interior to create the GUI from the ground up. Starting with an empty python sketch, the team has created their GUI window to have buttons, custom images, information display and other features for the user to interact with while driving the car.
Once fully completed, The Pi will be able to process the Jeep's sensor information and display things such as speed, rpms, and battery level on the same GUI being used for the head unit and digital dashboard. The team is currently working on all aspects of the touchscreen & onboard computer, including refining the GUI and configuring the CAN HAT. Interior is excited to continue working on these projects & putting the creativity of Relectric Interior members on full display.
The GUI program runs on the car's onboard computer, a Raspberry Pi 4 also being programmed by the team. Working on the 'Raspbian' Linux based operating system, the Pi is a compact & efficient solution for the team's goal of having a fully capable user interface running on a touchscreen, with a sensor communication system. The Raspberry Pi is connected to the Jeep's sensors through a special attachment known as a 'CAN HAT' (Controlled Area Network, Hardware Attachment Top). It allows the team's Pi to communicate with the car's sensors via controlled area network, a wired sensor communication system which has been the modern automotive standard for all cars worldwide since the 1990s.
ASSEMBLY
At the beginning of last year, a detailed evaluation of the Jeep's condition was completed to determine the best course of action for the restoration of the vehicle. After evaluating the condition as poor, we decided the best way to proceed was a body-off restoration. This included removing the Jeep's body from the frame and stripping it of the major components including brake lines, electrical wiring, and anything else that was left in the engine bay. The frame was sanded removing grime and rust, then painted with a rust-proof sealant. Upgraded shock components were installed along with removing old drum brakes and replacing them with new disc brakes.
what needs to be done/implemented this year.
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Finish installation of all body panels, seals, and wrap
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Mounting plate for motor – with mechanical
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Battery installation with mounts – with mechanical and electrical
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Braking and power steering systems - with mechanical and electrical
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Radiator for battery cooling – with thermal and electrical
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Body and Engine Control Module connection to the new drivetrain – with electrical
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Gas pedal and interface – with interior and electrical
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HVAC system – with thermal and electrical
Hard brake lines were installed before the body of the Jeep was placed back on the frame. New body mounts were also installed in this process. After completing the most difficult parts of the restoration, work on the vinyl wrap continued through to the end of the year, continuing into this year. Additionally, improvements were made to the interior of the vehicle. The rotted floor pan was repaired, the floor of the vehicle was resprayed with textured truck bed liner to make the interior more durable.
THERMAL
The Thermal-Sub Team primarily focuses on the thermal management of the vehicle, utilizing heat calculations and optimizations of processes. This is achieved by high-level research into flow rates, PID mechanisms, and many more mechanical models. The team focuses on the analysis & enhancement of radiators, expansion tanks, thermal efficiency optimizations, and the strategic design of tubing and valve systems.
Heat calculations were extensively studied to provide an in-depth analysis of heating and cooling requirements, establishing the range of cooling/heating required. The design highlights the usage of a bypass tube, ensuring the battery can properly reach maximum thermal efficiency. The radiator enables cooling of the battery if overheats, and the expansion tank aids in extreme fluid expansion and shrinkage during temperature shifts.
Products were evaluated leveraging an evaluation matrix, ranking each option by price, size, utility, power draw and specifications related to the product. This was finalized through thorough research by Canadian-based companies to guarantee that local products were implemented in the final cooling configuration.
