Efficiency and More

Engine Positioning

This weekend had a number of small enhancements which all came about from replacing the Pot-Joint rubber boots earlier.  The boot replacement required pulling the engine which was straight-forward and this provided the opportunity to tweak the engine position to assure the pot joints were fully engaged.  After about an hour of shifting and sliding the engine around, a new engine mount was attached along with re-positioning of the torque bar attached near the top of the engine by over an inch.  This greatly improved the drive-shaft alignment and thus the pot joint positioning.

Also, which the engine was out, I added rubber insulation between the engine mounts and the frame to absorb some of the vibration from the motor at low-RPM.  This is sometimes called cogging which is typically with BLDC motors.

The new motor mount is shown in the center of the photo.  Please ignore the tie-wrap since it is just a temporary addition. .

Cooling

The custom adapter (Black sheet metal) to the route the 200 CFM fan to the motor cowl was in need of some sealing, so a strip of vinyl weatherstripping placed all around provided a great air-tight seal, assuring all of the blower's air is going into the motor and is not wasted.

The black adapter, shown below the motor here, adapts from the 3" flexible hose to the motor cowl.  Near the center of the image is the cowl screw which is now all the way to left side of the slot since the cowl is rotated  fully clock-wise.

Timing

Many people talk about advancing the timing on electric motors to gain more power and efficiency.  Many motors are shipped for a balanced approach of setting the timing for both low and high RPM while maintaining symmetry for both forward and reverse operation.  Well with Jane, the motor is going to spend most of its time around 3,000 RPM in forward, so there may be some efficiency gains from tweaking the timing.  This involves rotating the fan cowl clockwise since the timing pick-up sensor is mounted in the cowl with the magnets attached to the fan-blank now installed.  The consensus is the motor should run more efficient (less heat, more RPM) at higher currents & RPM.  

New Electronic Dashboard feature

The Arduino proved its value once again.  The ultimate efficiency metric for electric cars is Watt-Hour/Mile.  This is similar to a miles/gallon measure used in the US for gas cars, though with WH/mile, a lower number is better.  Well 4 lines of code and the digital dash is now reporting this stat, allowing the driver to see how efficiently the car is running.  Some early cruising data is showing in the 100-150 WH/Mile.  The calculation was straightforward - = watts / (rpm*RPM_Per_MPH)  - This is equal to Watts/Miles_per_Hour.  It is probably time to add logging of the data to start to gather real efficiency numbers.  The Arduino has an SD Card to hold the boot-up-image of Jane Austen, so there is plenty of storage and a permanent USB cable.

Also, we attempted to cover the passenger side dash with vinyl.  This was mostly a learning exercise to figure out how to cut, stretch and glue it.  After 3 different glues, we settled on DAP StrongStik as the best to adhere to both wood and vinyl.  It was permanent, cured in about 2 hours and was not too messy, like the spray glue.

LED Lighting

Certainly an electric car should have LED exterior lights.  There are equivalent bulbs available for all of the lights, so a quick swap-out brings Jane into the current decade.  They are both bright, cool and more efficient.  This did require swapping in digital flasher controls for both the blinkers and the hazards.  The Hazards' wiring had been moved around a bit but that was quickly resolved.  The only remaining incandescent bulbs are the interior turn indicators and the illumination for the heater controls.

Bulbs Used

• Single element Yellow (rear turn-indicators) Yellow
• Dual Element front turn indicators + running lights White/Amber
• Dual Element Red - Rear brake lights + running lights Red/Red
• Single Element Small side fender running lights - Red

Small note: The front turn indicator/running lights were wired in reverse of how the LEDs White/Amber LEDs were, so more LEDs were illuminating when the running lights were on and the turn-indicator was difficult to see.  Swapping the two wires, resulted in the running lights being the dimmer mode and the turn-indicator being the brighter.

Results

The best news from all of this is two fold:

1) 200 new RPMs are now available from the timing change.  This translates into 2nd gear now topping out at about 37 MPH (previously around 32 MPH).  Third gear now can cruise at 45 MPH even on a slight incline.

2) Cooler running - With the increase air-flow and efficiency improvements, the motor's over-heating problem is solved.  Under normal driving conditions, the motor is staying below 70C.  On hill climbs, the temp approaches 90C but quickly drops once the climb is complete.  Even while cruising at 35 MPH, the blower is able to reduce the temp of the motor, which in the past, was not happening.  Previously, the motor would only cool while at red-lights and there was always a slight rise in temperature while cruising.  Today the air temp was 83F, so this was a reasonable test.

Next up....

More paint stripping  1 fender and 1 door are down to bare steel.