Prime- Forced regen trick.

We know about the holding HV-EV to get a forced regen. From a YouTube video... you will get around a 32mpg equivalent from this forced regen for later EV use scenario (don't quote me). If the engine is cold you will get much less.

I am not able to charge often. I would like to be able to EV on my short trips ( less than 3 miles round trip) to avoid the ICE warm up mpg hit.


If you forget to engage your Hybrid mode when you start your car, your battery will drain down in one of the default HV-EV or EV modes I have found that if you toggle between to HV-EV to Hybrid and back to HV-EV, you can reset your Hybrid target battery level to the currently displayed level. For instance, when you come to a regenerative stop or go down a long hills your battery charge in general will be above your current target level of battery charge (this is not displayed, but your car is working to maintain this level in hybrid mode). If you toggle out of and then immediately back into hybrid mode, the new target battery charge will be the one you have on your display. if you keep doing this you can ratchet up your target battery charge. This should be done when the ICE has warmed up.

Since this is not an all out forced charge, the Prime seems to be more efficient doing the Regen this way. From what I can tell, the Prime is still making above 50mpg equivalents!??!

 

To follow up. I have started this experiment with 156 miles at 72.4 mpg with 4.2 miles of charge remaining, I am now at 252 miles at 72.2 and 4.4 mile of charge remaining (All work trips). At one point, I was up to 10 miles of charge with 71.4 mpg showing. I have generated around 12 extra miles of charge using this trick for 3 short EV trips. So it looks like there are almost no perceivable hit for doing this. I believe this is because you are basically stealing regen miles just after they have been produced. The car is not put in position where it has to catch up with charging in an inefficient way. I would say there is no mileage hit for doing this trick except for the fact you have to keep pressing buttons.
I guess that the 12 miles in EV saved me from starting ICE 3 times.

I could see using the battery reserve in a camping situation away from charging stations where you wanted AC and didn't want the ICE to start up during the night.

 

Yes...Prime. Talking MPG savings. ...Forced charge (shortest amount of time) has a big MPG penalty Vs Toggling in and out of hybrid only mode just after regen stops when the EV miles to go meter has just moved up (This latching up takes a lot longer than the forced charge way) ..Note in the Charging mode, ICE is on all the time no mater what you are doing ( no mpg optimization).. ... Your mileage will vary.
Hybrid mode only (HV)... The problem with understanding this is that the miles to go EV meter is always moving above and below the target Miles to go target. This target is not displayed, you only know what this number is when you see the miles to go number on your display with you toggle in and out HV mode. You must remember what that number was when you pushed the button. In my experience you will see your Miles to Go To will vary between .3 above and below .3 this set target.

Example(not exact numbers)..I am in HV only mode cruising at at 50 mph and the EV miles to go is showing 5.5 miles. I hit the HV-EV button twice so I am go out of HV and then back into HV (toggle HV). I now know my target EV miles to go is 5.5 because I just set it (the computer has stored this value even though the meter values you see are varying from 5.2 to 5.8 mile to go ( +.3 to - .3 miles). I now brake and come to a stop using regen braking. The meter reads 5.9 miles to go. I now toggle out and back into HV using the HV-EV button to set 5.9 miles to go as the new target level. The car after this point will try to keep the miles to go center around 5.9 miles to go (+.3 to -.3 miles or 5.6 to 6.1). if you repeat this process over and over when you come to stop, you can move up your miles to go meter all the way up to its max allowable level.

 

Update..... I noticed that you cannot do the charge trick if you have already drained your battery all the way down to the point where "_" is showing in your EV miles to go display; it will be stuck there. The work around is to get into the forced charge mode (Hold HV-EV button until see the flashing "Charge" symbol, then let go). Once you have any amount of Miles to go showing you then can then do the trick.

 

20 miles to work to collect 2 miles of EV. The car cools down. Then use the 2 miles of EV only to Mickey Ds (no cold low milage ICE). Note, If you do the tick to the extreme, it will be just like doing a forced charge.

 

I am guessing that if you repeat the HV-EV to EV and back a few times going down this hill, you may get allot more, but I have not tried it.

In the equation somewhere in the B mode, is the fact the computer is forcing/allowing the engine to rev high to act as a drag so the battery does not overcharge and also slows the car down. On my gen 3, I had a scan gauge with a RPM tack mode, which confirmed this (not tried on the prime). Did you every notice the signs for the big rigs to use low gears going down the hill and when you pass them going down the hill you can hear their engines scream from the high revs (more of an old school manual trans thing). In the same vain, but more extreme are the Jake brakes on trucks (google).

 

I have boosted mileage up to 28.0 EV miles to go using this trick. The battery meter shows all but a pixel's worth to max EV. It seem like it was harder to make the last 5 miles to 28.0 EV. After hitting 28.0 the meter never moved above 28.0 and rarely moved below it when locked into HV mode. This is probably bad for the battery to stay at max charge while charging. Toyota seems to have engineered the car to drain the battery down to lower levels unless the driver hits the HV mode button at every startup.