"EV mode" asks the control unit to PLEASE leave the ICE off as long as possible. It is similar to "stealth mode" where you can drive gently on battery power, but in EV mode, you can use more throttle, and drive further before the ICE kicks on. The control until will fire the ICE when you go beyond 33mph, and whenever the car thinks the ICE needs to be run (for heat, charging, power, etc). IF it is really cold out, the ICE will apparently start even if you try EV mode. That's just a primer. Lots more info out there!
