Mark 7 Drivetrain

Mark 7 Drivetrain

Drivetrain: Motor Controller Mounting

Design Goals:

  • Low Center of Mass

  • Access to the service station & accumulator

  • Sufficient space for HV wiring

Functions:

  • Mounts the CM200 motor controller

  • Keep the CM200 safe under intensive driving conditions

  • Grounds the CM200 motor controller

Design Details:

  • There are four mounting points that mount directly to the chassis with bolts

  • Reduce welding and allow adjustment

  • The four feet lean inward to form a trapezoidal structure to increase stability

  • “Snake” shape rear mount accommodates the placement of MSD and allows easy HV wiring

  • 6061 Aluminum instead of steel for light-weighting

  • Welded with L-Angle on the top for easy installation

  • Angled at 45% to give clearance to access the service section and the accumulator

  • Hand calculation on the static load of the mounting, the dynamic load under 1.5g acceleration, and the clamping force needed for the bolts

Pump Choice:

  • Emrax required flow rate: 8 L/min

  • CM200 required flow rate: 12 L/min

  • Current pump flow rate: 25 L/min

  • Emrax pressure drop: 0.9 bar

  • CM200 pressure drop: 0.3 bar

  • Significant pressure drop caused by right-angle fittings, crimped tubes, and changes in tube diameter

  • Cooling loop architecture maps out minimal tubing requirements

Radiator Choice:

  • Mishimoto CRF250R aluminum radiator

  • Nominal value for dissipated heat requirement: 3.78 kW

  • Area needed for cooling: 0.104(m²)

  • Radiator cooling area: 0.726(m²)

Fan Specification:

  • 278.78 CFM required for fan cooling

  • Determined from energy dissipation and max operating temperature

  • CFM = 1.76 x Watts / allowed temp rise deg C

  • The chosen fan produces 300 CFM

  • Special funnel mounting designed to guide airflow, increasing the static pressure and airflow rate

Drivetrain Pictures

FEA Results:

FEA result of the three different kinds of mounting feet on SolidWorks 2023 under a 3.0 safety factor, using the data from the hand calculation

Max Deformation: 0.03388mm

Max Deformation: 0.313mmmm

Drivetrain: Cooling Loop

Max Deformation: 0.731mm