Uphill Strategies

I have a big clib of about 5 miles 8 klm. non stop at various degrees.
Kills my MPG

 

No matter how you attack the hills, your ICE is going to provide the power. Given that fact, you want to run your ICE in the most efficient manner, which usually means fairly hard but not wide open throttle (WOT). I don't know the range of the sweet spot for a Gen III, but the best general advice is to put your foot into it and get it over with, but try to avoid WOT.

Tom

 

Minimize accelerator pedal movement. Every time you move the pedal, the computer has to figure out the most efficient ICE RPM (although this happens in split second). Push the pedal and keep it at steady state.

 

The key is keeping the ICE at the most efficient RPM.

At slow speeds, that means hard acceleration. At high speeds, it means a lot less.

Your first hill is a classic example - you have to hit the gas pretty hard to keep climbing, so at 30mph you're still in the right RPM zone, but at 45mph you go into the red.

For your 2nd hill, get on the gas sooner and try to build some speed while it's not as steep, then ease up as you reach speed. Then try to hold it a little lower until you're over the top even if you lose speed in the process.

Do NOT use EV - that just drains the battery, then the engine has to work harder to replace the charge.

 

Take advantage of the engine.

Get up to the desired speed quickly, brisk not aggressive.

With the engine at a higher but steady RPM, it will find an efficient operating state and use the excess power created to top off the battery. It may appear that the climb is inefficient, but you'll end up better off overall. That's the beautY (and a big difference) between a FULL hybrid and an ASSIST.
.

 

I have a few hills and a stretch of highway driving on my commute. My strategy is to plan ahead for areas where I know the ICE will have to run either due to the hill or highway and try to use up the battery as much as possible before these areas. This strategy has yielded the best results for me. I definitely agree with the notion of using the ICE to get up to speed and use the EV for sustaining speed.

I realize that blindly using EV as much as possible doesn't yield the best mileage and that the prius computers figure out the best instantaneous thing to do for the best MPG. However, the prius is not going to be aware of upcoming driving conditions that will either be great for a long stretch of EV or great for charging either by a long downhill or ICE run.

 

If you can glide with ICE off, you will get double the climbing MPG. For example, if you climb at 25 MPG and back down with ICE off, you should average 50 MPG.

 

Try different things and report back on the effect. Keep really good records (temp, rates, pedal position, etc). It will help us all.

 

In run 2 what do you mean by "glided"?

 

Sorry to break this to you...

The faster you climb the hill, the less MPG you gonna get. It goes the same to slower climb (higher MPG). You'll need to perform those tests at the same speed if you want to compare.

 

Remember when comparing techniques that the Prius does *not* factor the battery SOC into mileage calculations. If you start at the bottom of the hill with a full battery and finish with an empty battery your MPG will look better than it really is.

This is what causes many Prius drivers to obsess about EV mode. It looks like you are getting fantastic mileage, but it's just an artifact of the mileage calculation.

Tom