I reworked my 'normalize' routine so it is now data independent. Graham miniscanner data is one record per observation with a time-stamp which makes analysis difficult. The 'normalize' routine collects all of the samples until it is about to repeat. It then writes them as a CSV record with the average of the time-stamps also giving a 3x reduction in file space. Even if the number of observations per cycle changes, in this case 4 vs 6, the missing data can be handled by a straight-line approximation in the spreadsheet.
I've attached the new format, and Friday data to this note:
- MG1 Nm
- MG2 Nm
- MG1 rpm
- MG2 rpm
- Battery Volts
- Battery amps
The new data is for the same route I used in the first post:
START ACCELERATION
This time I was parked where I could monitor on-coming traffic and wait until there was a pause:
Here you can clearly see the "EV" in the first minute when the car tries to keep the engine in a low-power mode, maximum EV, to warm-up the engine. During this time, I can accelerate the car drawing a deep discharge from the traction battery and high MPG. The acceleration energy comes from the traction battery, not fuel burn from a cold engine. BTW, the later NHW20 and ZVW30 models have expanded this EV mode nearly three times.
Where this comes into play is if you park near the exit where you can see on-coming traffic, you have the option of reaching cruise speed using traction battery energy and very high MPG. Once the car transitions to cruise mode, the recharge is handled by taking a fraction of the engine power from a warmed-up, efficient engine.
Speculation, it may be possible to install enough solar cells to put a 'peak charge' on the traction battery when it is parked. The advantage is it may handle the initial acceleration energy costs with no subsequent fuel burn impact.
CRUISE
Pretty much as before, the data is much smoother:
The surprise was how long the traction battery continued to draw a 5kW charging load. I've not seen this before and bears investigation.
STOPPING
Again, as before, here you can clearly see the ICE stop at 42 mph indicated:
Nothing new here other than once again seeing regenerative braking.
Vehicle Overhead
Looking at cases where there was no appreciable MG1/MG2 power, we can plot the traction battery load and find:
The NHW11 comes with day-light running lights which make a contribution but so too does the electric power steering and possibly other unmapped electrical loads. Here is another place to save energy.
MG1/MG2 Electrical Efficiency
There is not enough data and unexpected, the fast polling rate did not happen. I may need to do another configuration save to make a fast polling rate sticks. The other alternative is to take longer drives in steady state conditions and we've had a break in the hot weather.
Bob Wilson
ps. As I pointed out before, we can worry about calibration after getting the instrumentation working. There is a GPS receiver on the way and I'll be visiting a number of local benchmark routes. Plus I have high-resolution,
accelerometers. Capturing and reporting the data may give insights on how to measure the six, ECU variables. Calibration can happen anytime. For example, acceleration versus power.
There is an acceleration event dominated by traction battery and MG2 power along with a small amount of ICE power. Do the math using the NHW11 curb weight, add 10% for driver, fuel, full-size spare, tools and jack.