I live in a hilly terrain - daily commute is 40 miles RT. The current programming is over-zealous in keeping the battery filled up via ICE. There is so much opportunity for regenerative breaking (and thus saving LOTS of MPGs for me) that is wasted. Of course Toyota had to make a program that would sort of reflect "typical" driving conditions. But for me, it is not making best use of the awesome technology. I don't want to do anything unsafe or violate the warranty, but does anybody know if there is any kind of third-party "tuning" available - or even better - has Toyota considered providing more than one sanctioned programming so different ones of us can select a program better suited to our needs?

 

The answer to both questions is no. I wouldn't surprise me if someone played with the ECU to do that, but at the least, kiss your warranty good-bye. One of Toyota's trade-offs is to keep the battery's SOC within a small range to maximize battery life. I could understand why Toyota would not want to replace a battery that dies prematurely if someone messed with that program.

 

There is no way you can change ECU programing and I don't think anybody hacked Prius either, but what you could do is to develop some simple ways to help the car get better FE. I don't live anywhere near hills, so don't have much experience but probably gaining higher speed before up the hill climb and bleeding some speed as the climb continues up should help your FE. Don't use breaks too much, if the hill is long and steep enough to overspeed use B mode instead and it's better to accelerate briskly but shorter, than slower and for much longer. Another thing I noticed was that you get much stronger electric boost if the battery is fully charged, than when it's around 3/4 or bellow, so it's actually good to have battery fully charged at all times. And probably most important: keep accelerator pressed down only enough to sustain your speed, sometimes very little change in accelerator postion and speed makes for huge changes in FE. I could never get used to the fact that by trailling throttle at 43 MPH I get 20 MPG and by just barely slowing down to 42 MPH I can get 60 MPG or full electric mode, it is similar at higher speeds.

 

Since the idea is YOU change your habits to better fit the car, maybe ECU stands for - Easily Changed User.

 

What I'm about to say may be a little esoteric for a public forum... I should know better... but here goes:

I'm glad that the programming can't be changed. I also love driving underpowered cars. My reason? I like the creativity that is brought forth by limitations.

A fast, performance car that does everything "as it should" is not nearly as much fun for me as one that I have to work harder and THINK to drive it well. I'd much rather make the most of 100 horsepower than be self-indulgent with 300... I would be bored to death by the excess, and challenged far less to get the most from the car in day-to-day driving.

It thrills me that my mileage plummets when I hit the next hill. That is where the game is played, learning to drive the hills better. My fun is all centered around the mileage gauge.

The same notion is true in other domains of my life. I love having clients that have NO budget. I love living in a too-small house. I love that every day I live is one day less for me. It's all about making the most from what I have.

Thank God I'm not a millionaire. And I love my TCH, just as it is.

 

So did the Lexus finally go then?

 

Interesting project!
You know/observe you're approaching a certain grade of hills and you can prepare for that.
However, the problem is the vehicle does not know any terrain coming.
There is a study using Navi GPS system...
http://privatenrg.com/#terrainfollowing
It looks Toyota and Denso have in patent pending status.

Ken@Japan

 

Still have the Lexus but I have agreed to a price with an interested party (friend-of-a-friend), but she must wait until her current car is sold. Ho-hum. Thanks for asking!

 

The same way you need to change the habit not to floor accelerator when driving Ferrari unless you're on empty highway, you may want to change the habits when it comes to fuel efficiency of your TCH, but you really don't have to. Every car is different and to fully explore limits of each you need to learn a little besides passing the driving test to get the license. Hybrids are new and have some quirks that are different from what you may have experienced in the past. Either way, if you learn to drive more efficiently or not, TCH will have better MPG than similar ICE only car. I doubt Toyota will allow reprogramming of ECU, not with 100k/150k mile warranty on batteries we get. As a matter of fact forget about hacking ECU, I would be extremely happy if we at least had few mechanics around capable of fixing the thing if it breaks. I believe TCH has some limited capability to learn drivers habbits and act accordingly anyway.