What is the max ICE efficiency RPM?
 

One issue I have continually struggled with is how to drive up a hill with the ICE running when I'm pulse and gliding between 30-40 mph. Should I:

a) When the car's ICE starts just keep going up the hill with the minimum rpm that the vehicle will allow
b) rev up to around 2000 rpm which will allow me to accelerate a bit
c) rev on up to some higher rpm to get up the hill quicker.
d)pick up a bit of speed before the hill starts and let momentum assist a bit

It's easy to say "just do the one that produces the highest mileage", but that's a bit hard to measure as there are different variables almost every day. I'm sure it has something to do with engine efficiency. Has anyone seen a power band chart for the FEH ICE?

Any thoughts?

John S.

Re: What is the max ICE efficiency RPM?
 

The '09 and newer FEH's are much more engine efficient than the older 2.3L FEH's. I take a big bridge by maintaining the speed limit as I begin to climb the hill or bridge. Depending on traffic, I use a technique known as "Driving With Load" (DWL) in EV slowly decreasing MPH as traffic permits. You learn when the point comes the engine is going to start-up because of the increased load on the traction motor. Anytime you need more power than the traction motor will provide in EV, do an accelerator blip and start the engine prior to an automatic restart. Use the RPM that traffic will permit but in no traffic, use DWL and slowly decrease your speed. In my '09 FWD I use 2,000 RPM to hold my speed or slowly decrease my speed while DWL.

You can read more on this technique and others in the home page articles at http://www.cleanmpg.com/ One of the articles I wrote a few years ago was for the '05 - '08 FEH. If you look under the forum post for the FEH, I have posted most of the new techniques for the '09 FEH here: http://www.cleanmpg.com/forums/showthread.php?t=22158

In that thread, techniques changed as I learned more and more about the '09 FEH, so look at some of the newer post at the end.

GaryG

Re: What is the max ICE efficiency RPM?
 

Gary:

Just out of curiosity, do you know why the automatic restart uses more SOC than the accelerator blip? That seems strange. I'll definitely put that to use.

Also, while we know you can't go into EV with the engine, CAT and battery cold, and it looks to me like regen braking won't work until it's warmed up, it seems to me that battery will take charge from the engine, even when the CAT, engine and battery are cold. My FEH this morning had SOC below 40, but almost instantly it started taking charge on the way into work. Do we have specs that confirm that?

I had good mileage going last night with mpg into the mid 40s with prospects of getting to the mid 50s by the time I got home, when the water temp dropped into the 130s, course the engine started. Then after it warmed up and the engine shut off, I had a guy get right on my tail end and wouldn't pass. I couldn't really do P & G with a car 10 feet behind me. Moreover, I normally have one little hill where I coast down to around 20 mph. It's pretty steep on the other side and the FEH will pick right up on the other side. I didn't feel like I could go all the way down to 20 mph with this guy tail gating me. Drats....