There are a lot of MPG numbers being thrown around out there, but I never see the often overlooked important data regarding speed (MPH) and elevation points from start to finish. My early testing was all over the map, and not consistent. But within a couple of months I started to figure out what would make reproducible numbers. Basically you have to finish a MPG run where you started, or the results are skewed if you end up at a lower/higher elevation. Then temperature has to be the same. Gas has to come from the same station. And finally, you can't have traffic getting in the way. You have to keep at the same speed from start to finish. Plus tire pressure has to be the same on each run.
So I refined my methodology and went searching for a good test course. I found a section of I-84 that was the flattest section I will find anywhere in New York. It's a 65 MPH section between Stewart International Airport Newburg Exit 5A, and Route 6 past Middletown. 18 miles one way, and 36 Miles round trip from Exit 5A. Although I plan on doing speed and mode tests at speeds between 45 and 95, this course only allows me to do 55, 65 and 75 MPH. Anything slower would be dangerous in that traffic (as it was at 55), and doing 85 might get me a ticket due to heavy enforcement in that area.
Conditions were 38 to 44 degrees outside, dry air and dry road, 68 degrees in the cabin, 35 rear tire pressure, 37 front TP, same BP gas station 87 gas, and few obstructions in traffic. 65 and 75 tests were done twice and averaged due to some small amount of traffic obstruction (results were very similar on each run). The roadway has small rolling hills, but nothing too taxing. Started each speed test in Sport Mode to give battery excess to the next lower mode to be tested. That's more than fair. Adaptive Cruise Control was used on every run to maintain a constant speed. Regenerative Breaking paddles were only used exiting the highway on the off ramps. B Trip Counter was reset on every run at Exit 5A waiting at the traffic light for the left turn onto the entrance ramp. This is also where the Mode was switched.
Here are the results for this one course:
55 MPH Sport Mode = 50.0 MPG
55 MPH Normal Mode = 55.0 MPG
55 MPH Econ Mode = 52.3 MPG
65 MPH Sport Mode = 45.3 MPG
65 MPH Normal mode = 46.2 MPG
65 MPH Econ Mode = 45.8 MPG
75 MPH Sport Mode = 37.7 MPG
75 MPH Normal Mode = 37.8 MPG
75 MPH Econ Mode = 37.3 MPG
At 75 MPH, normal hybrid EV Mode never engaged. Not even on the small downhill sections. That is why the MPG readings were so close between modes at this speed. I'd try and do a set of 85 MPH runs on this course if it didn't have so many troopers in this area. Unfortunately, it's heavily patrolled.
I also did some local 45 MPH testing on a 20 mile round trip flat road around my house in 20 degree weather that came out to 54.6 MPG in Normal Mode. I suspect that number would have been much higher in 40 degree weather. My 26 mile gas station round trip run in Normal Mode with ACC on through heavy traffic and traffic lights, with a mix of speeds from 40-45 MPH to short runs of 55 MPH gets on average 55 MPG when in the 30's temperature range, but 64 MPG at 55 degrees. I expect all numbers to come up with warmer temps. Better hurry up with the rest of my testing before it gets really warm!
Is anyone else doing the same type of controlled testing? If so, what have you been getting for MPG numbers?
Phil