Well, I've been noticing this since the weather has gotten colder but I am only now putting it out there ... Is the noise I am hearing when the car is parked and the heat is turned on the ICE. There is no indication on MFD that the engine is on except for the fact that the MPG's are going down while standing still. The graphical display of the ICE, wheels, etc shows no activity. Also, I'm guessing this has more negative impact on MPG than cooling functions does in summer. Is heat more detrimental to MPG than cooling in summer and is that racket I hear the combination of the ICE and heater. Thanks in advance. Steve
Yep, the ICE runs a lot more and usually won't show anything on the MFD. This is why many of us block the grill...to help keep the ICE warm/prevent heat loss when sitting still or gliding. Also, running the heat, esp. early before the ICE is fully warmed up, will delay warm-up and reduce fuel economy. If you can stand waiting 5-10 minutes for the ICE to warm up before setting the temp you'll save gas.
The MFD shows only energy flows related to the drive system. When the engine runs only to supply heat it doesn't appear on the MFD.
A little trick I learned (the hard way). DON'T rely on the ICE to warm up idling. It WON'T. It gets the coolant to about 40C. The heater fans won't even come on at that temp. Leave the heater off (A/C off in my case using the switch on the steering wheel) until you have driven a few blocks. Once the coolant reaches 50C or just over the heater fan will start, and at about 62C you get full fan and full toasty warm air, AND bonus, the ICE will shut off when you stop, so you won't be wasting fuel. If while waiting at a light, the ICE starts, shut off the A/C (wheel switch again) to keep it from running uselessly. Turn it on once the light changes and you are ready to move again. Note that the low heat output while idling in the Prius is not "different" than other cars with small engines. It's just a bit more pronounced due the high efficiency of the ICE in the Prius. For those "newbies" who can't tell when the ICE is running, don't worry, you will learn to hear it. It took me a month or two before I noticed all the little clues to tell what was happening. The Scangauge just confirmed what I suspected, but it is also quite useful and not expensive.
We have a scan gauge and wait to put the heat on until the temperature is at 157 degrees which also means the car is in the 4th stage of warmup.
i dont know if it is shown on the mfd screen 100 % of the time, but i can see the engine charging the battery on the display screen , if i am in my car parked on my lunch break, etc i think its displayed on the screen 100 % of the time because i can sorta hear the engine come on or feel the engine come on and come off a lot of times i will sit in my car on my lunch break at 2:30 in the morning to listen to the radio and sometimes i just start the car because i don't want to run the 12v down the issue of the engine running status on display screen i am reporting is only if you go inside the car, start it, and just sit there and don't go anywhere. maybe while driving or stopped at a light, the engine will run but the arrows won't move. who knows.
What about the front and rear window defrosters? I wake up early, go out to the car and have to deal with the icy windows - so - I turn the car on and fire up the defroster buttons (both of them) on the steering wheel. I usually set the temp to 70 F and just let the defrosters do their thing for about 5 minutes (I'll run back into the house and grabba cup of coffee - take off my bunny slippers, and put on my jacket, etc...) - then I'm off to work. Naturally the ICE is running the whole time (that sucks) and it's maybe affecting my gas mileage a bit - but hey - I've go to defrost the windows - any ideas on this? Is there a better way?
Thanks to all the poster for confirming my suspicions (actually more than just suspicions) about the relationship between heater and ICE and MPG. It lead me to past posts about grille blocking and I learned a lot. I might try partial grille block solution when it really gets colder in the Philly area where I live.
I'm totally with you Scritty on the frosted windows on cold mornings. I have a garage at home so its not bad for me - plus I use an ebh which makes a huge difference. But, when I am away from home on a cold day it is going to be an issue. Also, I have a very short commute so I am expected terrible FE during the week - but - its only about 25 miles a week for my commute so no big deal I guess. It sure would be nice to hear from some of the more experienced cold climate Prius drivers on this particular issue.
As for frosted windows, you can always use the time honored "tank driver" method that is common in Northern Michigan. To do this, scrape clear a one inch slot (or less) low on the windshield in front of the driver's position. Now get behind the wheel, hunch low, and squint out of this slot. Moving you head from side to side in a scanning motion will increase the effective viewing area. I can't recommend this method, but there must be something to it, otherwise I wouldn't see it being used by so many drivers. As an aesthetic point, the "tank driving" method looks the best if you have at least a foot of snow stuck to the roof of your car. Three feet of snow is outstanding. Tom
