EV-Auto Mode: Warm-Up Cycle?

the engine always has to go through a warm up cycle when first fired up for pollution reasons, and thereafter, has to keep coming on to maintain minimum temp.
it probably fires immediately, as in hv mode, so it will be ready for use when needed.

 

From my experience, once the ICE kicks in it will stay running till full warm up cycle is done.

 

you wouldn't want to use a cold engine for quick acceleration bursts either. probably would kill it in no time flat.

 

maybe. i'm no expert on cold dry engine wear. but i suppose it has to happen on regular cars.

 

I originally thought that I would leave the car in EV-Auto all the time but exactly these issues of ICE warm-up and then premature cooling off have convinced me to manually choose HV from EV mode. For my use the transition is once per trip.

 

ya, that would drive me crazy. and you're in a warmish clime.

 

Since the system spins up the ICE with MG1 to a higher rpm than a traditional starter, i would not worry about engine wear; the oil pump is spinning at the same time.

Warming up the engine means it will be more efficient and cleaner running the next time it is needed.

 

In Japan, hybrids and some BEVs came out of the MITI LEV program. The program started back in the 1970s, IIRC, and were aimed at lowering vehicle emissions within cities.

toyota's goal with the Prius and following hybrids was for the lowest emissions possible. Reducing fuel comes second. Not warming up the ICE when first used means more emissions if it needs to fire up again later.

With the exhaust heat recovery and other improvements, the gen3 Prius was warming up in less time than the 3 to 4 minutes of a typical car mentioned in the following article. So the cost in terms of fuel use to reach operating temps is tiny. Then the benefits of a hot start on emissions can still have a positive impact up to 45 minutes after ICE shut off.

http://www.caee.utexas.edu/prof/kockelman/public_html/TRB15coldstarts.pdf
"Existing literature, as well as analytical tools like the U.S. Environmental Protection Agency’s Motor Vehicle Emission Simulator (MOVES), indicate that while total vehicle emissions have dropped significantly in recent years, those associated with cold starts can still constitute up to 80% for some pollutant species. Starting emissions are consistently found to make up a high proportion of total transportation-related methane (CH4), nitrous oxide (N2O), and volatile organic compounds (VOCs). After three to four minutes of vehicle operation, both the engine coolant and the catalytic converter have generally warmed, and emissions are significantly lower. This effect lasts roughly 45 minutes after the engine is shut off, though the cooling rate depends greatly on the emission species and ambient temperature.
...
Excess emissions attributable to cold starts vary widely by pollutant species, accounting for 10 to 30% of total mobile source emissions in most cases.
...
Research in Europe suggests cold start emissions may comprise as much as 50% of urban driving emissions
...
According to the EPA (2011), a hot start after a soak period of three minutes results in average increases of less than 10% in CO, HC, and NOx emissions, per mile traveled (as compared to hot running levels). After just 45 minutes, the catalytic converter has cooled significantly, and CO and HC are halfway back to cold-start levels, while NOx has recovered more than 85% of the difference. "

 

To the writer and reader of a scientific article, 'significant' means very high likelihood of a non zero difference.

 

I have test driven Sonata and Optima plug ins and one of the things I like most about them is they don't run the ice if power is not needed. I drive a lot of short trips and the warm up penalty drives me crazy!

 

That's the trouble/cost of living in nasty weather. My ICE is slumbering without startups for days. I'm a happy California boy (67+ years old). Our penalty out here is crowds, and much less of that pristine beauty from frequent rains and empty horizons. Everything has it's price.

Posted via the PriusChat mobile app.

 

You know, there is more to California than the LA and San Francisco Bay areas. Speaking as an escapee from the Bay Area.

 

Which is what makes California so wonderful. It's just that I'm entrenched here in Socal and hence recount my adventures from that vantage point. I'm locked into this area because of family ties, particularly 3 kids and 6 grandkids.
Most of my original family spread out in France.

Posted via the PriusChat mobile app.

 

Started out with a full charge in EV mode. 0.5 miles down the road, switched from to EV-Auto, ICE did not come on. At 1 mile, stopped at a traffic light. ICE did not come on. Therefore, there is no warm up cycle when in EV-auto mode.