Prius -vs- living on a tall Hill + Short Commute

Hi Tommerdoo. High 30's to low 40's might be about all you'll get in those circumstances.

The prius works best on descents where there is a series of smaller downhill sections with long enough flat sections in between to fully utilize the regenerated energy. On continual long descents, where there is little or no option of using the regenerated energy, then it does get a lot less efficient.

For a numerical example, consider a relatively mild slope that is just steep enough to allow you to maintain a glide (0 L/100km) for the entire descent. From experience I find that climbing on the return journey might use about 8 L/100km, giving an average of 4 L/100km (59 MPG) for the overall journey.

In contrast, given a relatively steep descent I will still use 0 L/100km on the way down, but now use about 12 L/100km on the way back up. This gives a much worse two way average of 6 L/100km (about 39 MPG).

If the hill is not very high then asymmetry is much less, as the battery will store much more energy when descending the steep hill, compared to a gentle hill of the same elevation. However for the type of elevation you are talking about (1500 ft), most of the regenrated energy will be wasted and there's just not much that you can do about that.

 

That sounds about right. I've noticed that I can never obtain as high of fuel economy trip averages when going up into the mountains and back as I can running around on the flats. Although the descent uses little fuel, the climbs use so much fuel (usually 20 mpg or less) that the averages still end up lower than flat driving.

The energy storage is very limited, so it's only able to capture a small amount of the energy from a substantial descent. The extra energy is wasted. The trip length is also pretty short for optimum fuel economy. The best fuel economy is usually observed on trips of at least 30 minutes each way. Not saying you should keep driving around in circles, just that it's a factor that lowers the average.

 

55 PSI is way too high, and dangerously stupid (if you ask me). The (FE) benefits will drop exponentially for every 1 PSI above 39 PSI, at your 42/40 pressures you are at about the max value for the effort.

Experiment, by all means, but safety first.

 

they talked to other people.