I am presently recovering from a severe shoulder sprain.
It was self-inflicted, the result of patting myself on the back too hard.
The problem starts with my wife’s Prius Prime. It has more-than-met our expectations in every respect. In particular, as-driven, it typically exceeds the EPA mileage rating, either on gas or electricity.
Lately, I’ve been trying a few techniques to try to squeeze some extra gas mileage out of the car. Just some around-town trips, driving it to try to keep the gas engine in its most efficient zone. Which, per Post #1711, boiled down to fast starts on gasoline, followed by coasting on electricity. Below, that’s an attempt to stay on the top of the green efficiency “hill”, followed by keeping the gas engine off while driving in the aqua “EV carve out” zone. (The labels on the contour lines are “efficiency”, the percent of the energy in the gasoline that is convert to motion.)
Results were encouraging. A couple of test trials showed mid-70-MPG for a series of trips and test runs, entirely on gasoline (using no grid electricity). Given that the car has an EPA rating of 55 MPG for city driving, I figured I was doing something right.
But at some point, it dawned on me that
- the current EPA mileage test is based on the typical U.S. driver (i.e., somebody who drives like a bat out of hell, whenever possible), and
- I have no idea what my “typical” city mileage is, because I almost never drive the car, around town, on gasoline.
In short, I made a classic mistake of trying to do an experiment without a control. I had no baseline to which I could compare my results. I literally didn’t know what mileage the car would get if I wasn’t fooling around with the accelerator pedal.
I decided to find out. Yesterday we took a trip out to my sister-in-law’s and back. About 15 miles, mostly on 35 MPH suburban roads, rolling hills, no traffic to speak of. Gas only. Didn’t need the AC or the heat. Relatively few stop lights. Driving normally. (But acknowledging that I’m a light-footed driver by nature, and that monitoring the car via a Scangauge 3 has done nothing but increase that tendency.)
In short, reasonably close to ideal conditions for a trip.
Results: The odometer clicked over to 80 MPG for the trip, just as we were returning to our driveway.
I am reminded of the following medical advice: If untreated, the common cold will last a week. But with proper medical attention, you can expect a full recovery in just seven days.
Thus it would appear, for urban hypermiling in a Prius Prime. As-driven, 80 MPG, for my suburban area. No fancy footwork required.
