Originally Posted by shrowell
I would suggest keeping Stealth mode as Electric only and EV mode being the mode where SOC is maintained ...
I think the real problem here is that "EV" and "Stealth" have the same real-world meaning: "EV" means "run electric-only as much as possible", and "Stealth" means "run as quiet as possible which means run electric".
To make the four modes assign themselves nicely, we need a new name for "maintain" (and perhaps even a new name for "performance" mode, although "Sport" means that to me). Perhaps there might even be a fifth mode or even 6th mode:
1. EV/Stealth: run electric-only unless SOC drops below 15% and the ICE must therefore be run.
2. "ER" (Extended Range) or "EMR" or "Efficient Maximum Range" or just "Eco Mode" (need better names): use both ICE and battery, while running battery down to zero-miles-left / 15% SOC. Generally limits performance. This is like economy modes in other hybrids.
3. "Hold" or "Maintain": keep the current SOC, plus or minus a bit
4. "Sport" or "Performance": like Hold but allow max performance by borrowing from battery, and raises SOC from 15% (not sure to what) so that there's borrowing-room. Can be lumped together with 3
5. "Recharge": like Sport but raises SOC to 90%. Maybe limit performance, see 6 .
6. "Recharge Sport": same as 5 but max perormance. Might be the same as 5 , if there's no separate "eco mode" switch.
If this were done with a separate "eco mode", you'd really have just three modes: drain, hold, recharge. Drain+eco is 1 above, drain without eco is 2, hold+eco is 3, hold (no eco) is 4, and there are the two recharges as well.
I think this way (eco / no-eco; drain, hold, recharge) is easier to explain and think about
: eco means "if the ICE is used at all, we attempt to burn as little gasoline as possible" and non-eco means "ICE will rev up if needed for performance". Hold and Recharge naturally require running the ICE.
"Eco" / "no-eco" can be indicated by a green leaf or circle (and green lettering), non-eco with orange lettering and no additional marker. (The additional marker is mainly for dealing with red/green color blindness, not really sure if it's required since I'm not color-blind and have no experience there.)
One big drawback, of course, is that cycling through 6 modes is a lot of cycling. Perhaps pull-and-hold might toggle eco/no-eco so that it takes just two short and one long to make the largest change.