My commute is 22 miles on So. Cal freeways. This tank, I've been employing all the hypermiling skills I can handle in an effort to break 50 mpg.... and I'm very close. Strange thing is MOST of the commute is on level freeway, yet I seem to get better MPG on the morning drive then in the afternoon. Today, I figured out why. I noticed that through about half the afternoon drive, I had one green regen bar lit. I figured out this meant that the ICE was under extra load to charge the battery. I don't really know why, though, since the SOC indicator showed almost full (only two bars not lit).

About half way through the ride, I felt a little (almost imperceivable) surge, and the green bar was gone... and I was able to add about 5 mpg to the instant FE gauge.

I'm guessing this happens every day (I'll confirm on Monday's commute!). Any idea why the forced regen occurs like this? By the way, I'm driving a steady 55 - 59 mph, temps are high 70's. Thanks.

 

dude, all your hypermilling is nothing if you drive 59! drive 53-55 and you'll see... and don't panic when the redneck in the f150 in your back is inpatient.. he will pass eventaully...

 

Yes, I've seen that sometimes. The regen policy is not always the same for the same driving conditions. Perhaps the computer tries to be really clever. If it sees you driving steadily for a long time without any regen opportunity it might say - "Hey, the way I'm being driven, if I'm not going to get any chance to charge up the batteries I might as well do a trickle charge now". BTW, trickle charging is healthiest for the batteries.

I think you might be able to cancel that forced regen by stirring the pot a bit. Take your foot off the gas, coast for a bit with several bars of charging, then accelerate back to your former speed. That may knock out the forced regen.

 

Honda's IMA is a little crazy sometimes. It gets "charge happy" sometimes when you can't keep it from using regen. It also gets "assist happy" sometimes and assists even when the instant gauge is on 60 mpg. When IMA picks to recharge is a mystery. Sometimes it will charge going uphill when you need assist and quit when you are going downhill. Crazy.

Fortunately it works fine most of the time.

 

I don't think it's as crazy as it may seem. One thing that it does, which is most often the reason for "crazy" behavior, is taking its time to change the CVT's "gear ratio". For example, if you're climbing a hill reving the engine at 3000 RPM and you let off the gas pedal a bit, you won't see the RPMs drop immediately. Instead, you'll see assist disappear and perhaps some regen appear. After perhaps ten seconds, when you haven't hit the gas pedal hard again, the RPMs will gradually come down and the regen will disappear.

Another example, cruising on the freeway at 60 MPH, at perhaps 2100 RPM, with cruise control, you hit the incline of an overpass. The instant reaction is a high level of assist. Then the RPMs start to increase and the assist goes away. At the top of the overpass you may be at 3000 RPM but you don't need that power anymore. You get regen. The RPMs come down gradually.

It's all designed to change the load on the ICE very gradually and minimize the changes in CVT ratios.

 

You may be getting better MPG on your moring commute because it may be downhill, yet to subtle to notice.
Then, of course, your afternoon commute would be uphill.

 

True, but not by a significant amount. My exit off the 91 freeway is at about 300' elevation. My office is at about 150'. They're 20 miles apart! No hills in between (other than overpasses).

Also, Lakedude's comment about it charging on hills is quite valid! It's done that several times (that I've noticed!) and I haven't a clue why it's doing it! Oh well!

 

I've learned to trust the MPG meter. If it is over 80 you are going downhill. If it is under 60 you are going uphill even if you can't tell it. (steady speed summer driving)

 

Not to argue but slopes too gentle for the driver to detect can make a big MPG difference as Lakedude said.

Also is your house above the freeway exit?

I ask this because I've driven a hybrid daily for two years to commute on the 405.
The start and stop elevations have to be almosst the same; definitely well below 50 feet.
I always get better 3 or 4 MPG in the afternoon.
I assume it is because it is warmer.

A GPS unit will show your your elevations if you have one or can borrow one.

 

The difference between your monring and afternoon commute mileage could be the direction the wind is blowing?