Cold Morning Warm Ups

I believe you know Prius uses motor power only for the first 50 seconds drive, then your slow driving won't be a big difference.

People used to drive normally for the first 50 seconds, then the HV battery will be drained very quickly because of the motor only driving.
It may cause the forced charging which is not good for fuel economy.

Ken@Japan

 

If you're moving, you're also sending cooler air into the engine bay, which *might* prolong the warmup if it's cold enough as compared to sitting still?

I'd say, if your speeds are under 35mph for the first minute of the drive, you'll be OK. You can always hit the gas a little more and force the engine to rev up and provide power. Yes, it'll use your battery, which if you drain enough will result in reduced power initially due to the depleted battery. If you would have to pull out onto a highway to start, I'd recommend letting the engine warm up first.

 

It's automatic with Pearl (the 50 sec warmup). Takes that long to operate the Mexican garage doors (they're Manual ).

But I still get terrible mileage (for a Prius). Mostly due to short trips and our 6 month winter. I guess I shouldn't complain too much though. Now that I have a grocery store only a few miles away the trips are even shorter but I put very few km on Pearl each year now.

MFD is down to 6 l/100 km (gets better as I get more km on the current tankful, finally mixing in a few longer trips with the many short ones). It started out around 8 l/100 km, and will finish around 5.9 if the last two tankfuls are any indication. Pearl's MFD is still pretty accurate, even at these extremes off the ordinary. Summer sees 4.5 to 4.7 typically.

 

Here in Houston it is not really cold yet maybe we are 40-50 at 5 in the morning when we leave. My wife drops me off at the bus stop 5 miles away. So I start the car to warm it up for her and my son who both are usually in the pj still. I go out 2 or three mins before we leave and start the car and crank the temp on hi. I turn off Eco mode. Some times we get out there the engine has turned off some times it shuts off just as we are getting in. I en drop the temp back down to 74 ish. And switch on Eco and auto. Car is warm enough for them and I can not say I have seen anything worthwhile in drop of mpg verse the same drive in the afternoon. Maybe if it was colder it would effect it but we don't get down to the 30 until January and February.


Steven M.

 

I was actually wondering about this same topic myself. I'm not sure about anyone's personal preference, but I normally warm the car up for 10 min or so and let the frost melt away. That's me though, I don't like getting into a freezing car with an 1/8th inch of frost on all the windows. I also don't mind the little bit of fuel wastage in this.

 

You could scrape the frost off and save the fuel. If that's not an option, then the warming up is also a safety related thing for you. If you can't see out the windshield then it's a major safety issue for everyone.

That said, I just jump in the car, start it, and go. I also leave for work after 9am, and I park the car so the windshield faces where the sun comes up, so it's usually just moisture on the outside by then.

 

I wear a jacket and thin gloves in the car in colder weather, so I'm not concerned about heating the cabin. I just need enough heat to keep the windshield and windows clear.

Until I get the garage doors fixed we're outside and I scrape. But it's often a scrape and defrost combination because the defrost takes a while to defog windshield and side windows and often just scraping isn't enough.

Turn on car.
Turn on front and rear defrost.
Get out.
Scrape rear side windows.
Scrape front side windows.
Scrape front windshield.
Scrape rear windshield.
Get in and go.

If I scrape without turning the car on it takes longer, but with the car on it's generally pretty quick.

I'll turn the car on at different points depending on how severe the frost is.

Also, silica gel or cat litter (more effective) is suggested to reduce the humidity in the car so that the windshield and windows don't frost or fog as much.

 

I just start and go according to manufacture recommendations, albeit very moderately for the first couple miles, typically between 25 and 45 mph. Anyone who professes they know better than Toyota or any other auto make - doesn't. I've been doing that for at least 20 years with no harm to ICE in any of my cars. Thankfully, I park in the garage and don't have to scrape frost on the rare cold morning in coastal SC. I also have the heated leather seats which I crank on and leave the heat off until the ICE is warmed up.

 

My cars mileage also started to suffer when it started to get cold (0 to 5 °C) and after mounting the Michelin winter tires. The car sits outside 24x7 and it doesn't help much that I have to climb a hill about a minute after driving off my driveway.

Besides of the fact that in most European countries warming up a car (let it sit and idle for several minutes) is forbidden I learned that immediately driving the car helps much in warming it up quickly. When the engine is under load the exhaust temps rises what helps to let the catalytic converter work the proper way as well as the exhanger for the heater has quicker warm air.

In my case I start the car and drive slowely to the open road. After 10 seconds flat road I have to turn into another one that heavily climbs up the mountain. I learned that this helps a lot in warming up the car but also mpg drops a lot. I always try to keep the rpm below 3000 what works to have a speed around 70-80km/h on that road. I once had to drive much slower behind a truck and mileage was significantly better then. So if I'm not in a hurry (well I have to catch a train in the morning) then I go slower than usual what really helps. I will look for some grill blocking stuff to find out if this helps as well.

 

It seems most new cars need very little "warm up" or none. However, I think a minute is more than enough time to get the essential oils flowing in extremely cold weather. Furthermore, if the vehicle is parked outside, there's usually fogging issues which require me to wait until the Defrost/defogger has time to start defogging in order for me to drive safely anyways. I think I read it best in a post from ItsNotAboutTheMoney about scraping of the ice and stuff. It works!
Also, I notice that while driving at a constant 30-40mph with a slow acceleration that it takes a couple of minutes before the car acclimates to driving in extremely cold weather (0-15 F); just take it easy on the gas until it starts to perform more "normally" in 32+ F weather.

-Cal

 

A block heater is the answer your to this problem. Have it on a timer too come on a couple hrs before you leave. H

 

This is also a pretty good and viable option. Personally, I just take it a little slower on the super cold mornings and this works for me. Or at least until I get my indoor garage back. *yay*

 

It really hurts my MPG during this frigid Long Island mornings,; I try to let idle my PiP for a couple of minutes until all the fluids get to temp and in a few more I'm in the SS Parway heading North/East.
I can't even use the electric block heater

 

Yeah I hear ya - either way my MPG's took a beating this month too. It's hasn't been this cold in New York in a long long time for this long of a period as well. I've averaged 36MPGs over 1800 miles; the lowest since my 2005 Prius over that many miles. Must be a combination of the cold, the slush, and probably some of the trouble I've had getting the car unstuck (for those of you who know snow, knows sometimes no matter what vehicle you drive, you gotta do the whole back and forth car rocking). Hard to know/say. I've also lowered my air pressure 3psi's from recommended to try to put more rubber on the road - might not be much, but with the icey roads and other road issues, the handling just feels slightly better even if I have to watch the potholes more.

 

Actually higher pressures work better for slippery condition!h

 

I'm still with my 40 front 42 rear...............

 

I also live in South Jersey. I drive away immediately. I notice that in the first minute the car is very slow to respond to the accelerator so I don't push it. The expressway is about 5-10 minutes from me. Yes, mpg go down in the winter. It happens with all cars.