Plug-In Prius: real winter driving

It was 25°F here this morning. Without the heater on, the engine stayed off.

 

Here's a drive I filmed the other day, intentionally running the engine for heat...

With the temperature at 24°F, resistance was futile. I couldn't let the opportunity slip away. I had to capture a drive on video that documented what happens when you start with a cold engine and drive the entire time with the heater on the generous side. The filming setup was a challenge, of course. I had to avoid blocking the vents to keep the windshield clear. I also had a new mount for the dashboard camera and a new Wi-Fi transmitter for the scenery camera. Both had problems along the way too. But there's no stopping once you start. You only get one chance and just hope for the best. Next time, I'll be better prepared. This time was intended to be practice. Luckily, the video turned out well enough to share anyway.

Watch the instant MPG readout next to the speedometer. Once the system (heater & emission) is fully warmed, the engine shuts off and EV mode automatically engages. With the heater temperature set to 75°F and the blower set to medium for both windshield & feet, the ice cold coolant would take several minutes to warm. Following that, I was able to drive along in EV mode. Later, the system automatically switched to HV mode to produce more heat while also assisting with propulsion and generating some electricity. Watch for that; the MPG will drop below 100 briefly.

Those engine on/off cycle happens several times throughout the drive to the coffeeshop and back. This is the same route I filmed several times with the 2010 Prius. Now using the plug-in, even under these terribly inefficient driving conditions you can easily see how the extra electricity really boosts efficiency. The 17.9-mile drive resulted in an overall average of 92 MPG, with 0.9 mile of EV still remaining.

Normally, I wouldn't have the heater running as much and I'd take advantage of the heated seat. That will allow for higher efficiency, since the engine would run less often. But for the sake of demonstrating ordinary circumstances without any question of comfort, I didn't. After all, passengers in back don't have seat heating available.

 

I filmed again, it was my morning commute taking the route along the river. It was 25°F, but in true Minnesota style I saw no need for the heater. My winter jacket did the trick, even with the windows cracked to prevent fogging. There wasn't a need to turn on the heated seat either. I was comfortable, gloveless and driving an iced coffee.

The engine stayed off until I wanted it to start. Toggling the HV/EV button when turning onto the 50 mph section works best. With a 17.3 mile drive that route, there isn't enough battery to travel entirely EV anyway. And of course, there's the nice benefit of EV replenish resulting from the engine running to produce thrust & heat.

Anywho, you get familiar with you commute after awhile, so the what to do when becomes rather mindless. So, pushing the button again while on the ramp to merge onto the 55 mph is a rather routine thing to do too. And I did, saving electricity for when it could be better utilized.

I ran out of EV as I entered the parking ramp. That was perfect, since power demand was low enough for Stealth mode to get me to my spot, still driving with only electricity. You can see it automatically switch in the video (coming soon) too.

Despite the cold temperature, the resulting average was 204 MPG. Using the heater, efficiency still would have been in the 100's. No complaints about that. The plug is delivering a significant boost, exactly as it was designed to.

 

Clearly, something else is at play... because I certainly haven't.

If you don't have the heater on and don't exceed the ECO zone (go into the red POWER area), it won't happen at temperatures above freezing. Below it hasn't for me either, but those opportunities to try have been sparce so far.

I guess my next filming will be that. I'm hoping soon too, since I just discovered a change for the new camera to better pick up the dashboard info.