heat motor before or not driving in winter ?
In winter, is it better for fuel effeciency to let the motor heat itself (I mean motor on and without driving) or let the motor heat during the drive ?
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Re: heat motor before or not driving in winter ?
Reasonable question. The engine runs better when warm so it may be better to let it warm up a bit first before taking it for a ride.
You will get better fuel efficiency while driving if you let it warm up first, but you'll have burned more gas in the five minutes warming up than you'll save. You can use an electric engine block heater, but it would have to be plugged in for a few hours ahead of time. That would save a tiny amount of gas, which would be good for the environment, but bad on the wallet because engine block heaters aren't cheap. I certainly don't know the weather in all of France, but my memories of Paris in late January were that it never really got below -5C. Block heaters are more common in the very northern US and Canada where morning temperatures routinely get down to -20C. |
Re: heat motor before or not driving in winter ?
That confirm my first idea, it's better to ride even your motor is cold ! but accelerate gently !!
I ask because I begin my ride every morning in town traffic... the worst case to reduce fuel consuption... and I only ride 20 km to go to my workplace... So i'm trying to find all the tips to improve my fuel efficiency |
Re: heat motor before or not driving in winter ?
Hi,
It is pure speculation on my part if this helps with the HCH engine systems. We find the Prius engine has a series of significant warm-up phases:
GOOD LUCK! Bob Wilson |
Re: heat motor before or not driving in winter ?
Bob is about right about how the HCH warms up. Ideal from a fuel efficiency perspective is to be able to drive gently at perhaps 60-80 km/h directly from start. Idling is never good for FE (and not for the engine either).
And yes, the hybrid functions come on gradually as engine temp rises, after about 2-3 km. The logic is fuzzy, so it will depend on many other factors. For example, on a hot day I get auto-stop at the first red light, 100 m from the garage. On very cold days, the engine is idling at red lights even 10 km after start. When engine is cold there is regen only at higher speeds. Etc., etc. |
Re: heat motor before or not driving in winter ?
Hi Rolf and Bob !
I think you're right ! I get auto-stop when the temp indicator has three bars or over, never when it is above. And I can use "EV mode" only when the temp indicator has more than 5 or 6 bars. All depend on the motor's temperature wich depends on the weather.... So in winter, during the 1st km, to reduce my fuel consumption, I let idling "tow" the HCH in "D" mode, because I'm driving in town, so my speed is low (about 30 km/h) but my instantaneous consuption is only about 3,5 l/100 km (about 67 mpg)... PS : Thanks for speaking in metric system !! LOL |
Re: heat motor before or not driving in winter ?
Hi,
Originally Posted by eco.conduite.free.fr
(Post 191586)
. . .
I think you're right ! I get auto-stop when the temp indicator has three bars or over, never when it is above. And I can use "EV mode" only when the temp indicator has more than 5 or 6 bars. All depend on the motor's temperature wich depends on the weather. . . . After I got my block heater, I took several hours to go out and measure how long it took to warm up the engine block. Knowing the power rating and the warm-up curve, I quickly figured out that:
We think Toyota puts a higher premium on engine warm-up and may be putting an additional load on the engine during warm-up while in "D". But when in "N," it can not put an additional load so ordinary, no-load idling occurs. Some of us think no-load idling warms up the car just about as fast and with a lot less fuel burn. But this is in the 10s of seconds over a 300 second interval, not hardly worth it. The extra fuel burned is not proportional to the benefit gained: http://hiwaay.net/~bzwilson/prius/pri_warmup_100.jpg http://hiwaay.net/~bzwilson/prius/pri_warmup_200.jpg This last test was run during a typically, hot Alabama summer. You'll notice the block heater allows the engine to quickly reach a state where it will auto-shutdown. Some of our Japanese friends posted about this and they have adopted the practice of year-round block heater usage. Fortuantely, it is only needed for 30-60 minutes before starting a trip ... about the time you decide to get dressed to go, start the heater. Now some of us have experimented with 'spoofing' the engine coolant thermistor into giving a warmer indication than the actual value. This is a rather advanced technique but simple to implement. The key to success was:
Bob Wilson |
Re: heat motor before or not driving in winter ?
One thing we do in the colder climates is to block the air flow into the rad..All kinds of methods to do this. This allows the temp to get up to operating temp. much faster. About half the time! Most people use a block heater as well. H
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Re: heat motor before or not driving in winter ?
It's very interesting Bob !!! It seems you have time to experiment ! you're lucky !
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Re: heat motor before or not driving in winter ?
Originally Posted by eco.conduite.free.fr
(Post 191728)
It's very interesting Bob !!! It seems you have time to experiment ! you're lucky !
I bought our car used via Ebay in October and flew 1,300 km to drive home. My first tank gave 39 MPG (6 L/100 km.) I briefly thought about turning around and returning the car to the seller. But I knew the USA EPA rating was 45 MPG highway (5.2 L/100 km) and 52 MPG city (4.2 L/100 km.) So I spent the remaining time on this first trip to measure the mileage at different speeds and found I could meet and even exceed the EPA ratings at 105-112 km/hr (65-70 mph.) I like to have at least two or three 'hybrid' projects at any one time and switch between them as time and resources are available. Most of my petite projects take a couple of months or longer to complete. If I might suggest some interesting HCH projects (my apologies if the HCH community has already done these):
GOOD LUCK! Bob Wilson Bob Wilson |
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