Just joined the Prius club with a 2012 Prius 4. This is also my first Hybrid and I'm still in the learning phase of my new toy. One thing I noticed a few times now is that when I'm stuck in traffic or waiting for a light to turn green, the engine shuts of completely (I expected this) but it turns itself back on after a couple of mins. even when I didn't move at all and my foot is still firmly on the brake. Is this normal and why? Who can explain this to the confused? happy to join this forum !
Hi. Yes, that's normal. The engine will run to keep the coolant in a specific temperature zone, and also as and when required to either charge the HV battery ( if needed ), or heat the cabin. Take a look around, the search function is also very useful Edit:Just seen where you are.. Aircon use will also use the HV battery - so the engine could be running to keep that "in the charge zone". Welcome to the forum !
Does this happen every time? Or does it happen shortly after a cold start? If the outside temps are cold the engine turns ON more frequently to heat up.
Next time look at the battery ICON. If it is down to two bars showing, the engine (ICE) will come on to spin the generator to charge up the hybrid battery. If the battery is above two bars, then it is coming back on to either heat itself up or the interior of the car.
Are you driving mostly on battery charge such as you're continually depleting it? If so, don't do that as that isn't good for fuel economy. Learn the pulse and gliding technique.
If you turn off heating or AC or other high energy drains (defog) while waiting for the light, it will not happen and you will save gas and wear and tear on battery.
Thanks guys! Yes I do realize there's a wealth of info. here and I should read them as time permits. The behavior I described doesn't seem to happen all the time and after reading all your posts I may just have seen my car bahaving normally. It happened this morning on my way to work and it was a colder than normal morning outside. Also I just did my first fillup after 450 miles (with 2 bars remaining at fuel meter) and it pumped exactly 9 gallons giving me a calculated MPG 50. Cars meter showed 51.6 MPG. It's nice to see I'm saving on fuel now
I'm wondering if you have the car in 'Eco' mode where the green eco light is lit? That appears to cause the engine to switch on and off more often than in 'normal' mode (where the green eco and green power lights are not lit), during the warm up cycle. Eco is good for relaxed city driving, normal mode for faster roads and the highway and power mode for fun, overtaking or pulling away quickly.
Seems like your car MFD is close to calculated, than other 2012s. We have been seeing somewhere around 7% discrepancy between calculated MPG and MFD MPG.
Then it sounds like the normal warm up period, especially with the heating on as that can, depending on the traffic, take a while sometimes. You'll also experience the engine revving when you reach the bottom of a long hill - that is normal. The a/c can also make a loud buzzing noise when first switched on on a hot day - that is normal too.
ECO Mode, minimal use or turning of Heat or A/C, and Heated Seats(but not much) will minimize the ICE from running.
