Prius uses vacuum flask to heat up cold engine

[zerosoma]

Just read this on wikipedia :

Quote:
In the U.S. and Canada, a vacuum flask is used to store hot coolant when the vehicle is powered off for reuse so as to reduce warm-up time. The Prius engine makes use of the Atkinson cycle.

When the vehicle is turned on with the "Power" button, it is ready to drive immediately with the electric motor, while electric pumps warm the engine with previously saved hot engine coolant before the internal combustion engine is started. The delay between powering the car on and starting the internal combustion engine is approximately seven seconds.


Brilliant to say the least. The engine is warmed up using this "hot coolant" stored in a vacuum flask (much like a thermos for heat conservation) before the engine kicks in. Virtually no start-up wear. One more reason I love my car.

 

[Kiwi_ME]

Yes, I think that was implemented starting in the 2004 model.

If you read the technical papers on the Hybrid Synergy Drive design there are lots of small enhancements made to improve efficiency. One was removing the seals that kept oil out of the motors and just let them get wet and drain as required.

Engineering at it's best.

 

[zerosoma]

Originally Posted By: Kiwi_ME
Yes, I think that was implemented starting in the 2004 model.

If you read the technical papers on the Hybrid Synergy Drive design there are lots of small enhancements made to improve efficiency. One was removing the seals that kept oil out of the motors and just let them get wet and drain as required.

Engineering at it's best.


Freakin' awesome!

I won't even have to worry about using 0w oil in the winter.

 

[gathermewool]

Originally Posted By: zerosoma
Originally Posted By: Kiwi_ME
Yes, I think that was implemented starting in the 2004 model.

If you read the technical papers on the Hybrid Synergy Drive design there are lots of small enhancements made to improve efficiency. One was removing the seals that kept oil out of the motors and just let them get wet and drain as required.

Engineering at it's best.


Freakin' awesome!

I won't even have to worry about using 0w oil in the winter.


How long after the car is parked will the reservoir cool to ambient? What if you drive at speeds greater than full-hybrid mode soon after starting?

 

[zerosoma]

Originally Posted By: gathermewool



How long after the car is parked will the reservoir cool to ambient? What if you drive at speeds greater than full-hybrid mode soon after starting?


It takes 7 seconds for the engine to kick in which means you will be driving purely hybrid until the engine kicks in. That means it warms the engine in that 7 seconds. How it keeps warm I have no idea, but I don't know how everything works in it. I know I hit the highway almost immediately but by the time I hit the highway hybrid mode has kicked off and the engine kicks in and the air blows warm.

 

[Trav]

VW messed around with this idea over 30 yrs ago. I have no idea if if ever got into production or what happened to it.
It was in popular mechanics or popular science late 70's early 80's or so IIRC. I was surprised to see Toyota adopted it.

 

[[email protected]]

My 2007 Prius will hold the coolant for at least 24 hours for sure. I havent let the car sit longer than that because its my daily driver, so I dont know if it would pump coolant from the tank after 1 day. You can hear the CHRS pump clearly from the inside the car. It runs for about 5 seconds most every time you turn the car off, and then start it back up.

Per my ScanGauge2, the ECT temp will be usually 1-5 degrees (f) within the ambient temperature, after sitting all night.

Once you hit the Power button in the Prius, it pretty much activates the heated coolant storage pump right away. Without the ICE even starting yet, the stored warm/hot coolant sends my ECT reading 80+ degrees than the ambient temperature.

Cuts down on emissions by shortening warm up time. Also I get cabin heat pretty quick too

Many upsides to it but lets face it - one major downside is its another electric pump to go bad. They get noisy and stop working and arent exactly cheap to replace! (mine is noisy right now and has been since I bought it - Im waiting for it to croak out totally before I replace it)

 

[gathermewool]

Neat! Learn something new every day.

 

[Doog]

Originally Posted By: zerosoma
Just read this on wikipedia :

Quote:
In the U.S. and Canada, a vacuum flask is used to store hot coolant when the vehicle is powered off for reuse so as to reduce warm-up time. The Prius engine makes use of the Atkinson cycle.

When the vehicle is turned on with the "Power" button, it is ready to drive immediately with the electric motor, while electric pumps warm the engine with previously saved hot engine coolant before the internal combustion engine is started. The delay between powering the car on and starting the internal combustion engine is approximately seven seconds.


Brilliant to say the least. The engine is warmed up using this "hot coolant" stored in a vacuum flask (much like a thermos for heat conservation) before the engine kicks in. Virtually no start-up wear. One more reason I love my car.


Before we all start jerking over this revolutionary design, how long does this coolant retain heat over 40F when the ambient temperature is below 32F? Just wondering.

 

[Doog]

Originally Posted By: [email protected]
My 2007 Prius will hold the coolant for at least 24 hours for sure. .


what about in the Winter when it is below 32F?

 

[Doog]

Originally Posted By: zerosoma
Originally Posted By: gathermewool



How long after the car is parked will the reservoir cool to ambient? What if you drive at speeds greater than full-hybrid mode soon after starting?


It takes 7 seconds for the engine to kick in which means you will be driving purely hybrid until the engine kicks in. That means it warms the engine in that 7 seconds. How it keeps warm I have no idea, but I don't know how everything works in it. I know I hit the highway almost immediately but by the time I hit the highway hybrid mode has kicked off and the engine kicks in and the air blows warm.


So if the car has been sitting outside for 72 hours in 20F it will warm the engine in 7 seconds?

 

[friendly_jacek]

That future was dropped in 3rd gen Prius (2010+). Not sure why. Instead coolant is warmed by exhaust gases after the cat. Probably cheaper to make.

 

[[email protected]]

Doog, I dont believe the CHRS was ever implemented in the Prius to completely bring the engine to 185f. It was, however, designed to aid in the warm up process and it does a good job of that. Like I said, verified by my SG2, there was a morning last week it was 28f outside. My SG2 read the ECT at 30f. I pressed the power button, the CHRS pump ran immediately and the ECT temp per my SG2 now read 112F. It doesnt take much longer to get to 180f after that. As an advanced low emission vehicle, this helps the Prius meet that standard by reducing cold start emissions. It also saves on wear and tear on the ICE, keeps mpg's from dropping like a lead ball, and gives me warm hands and feet right away

The last time I drove the car was 5pm the day before and it was now 8am the next morning so that was -what- 15 hours? So the coolant in the thermos at least stays hot for 15 hours.

I live in Michigan FWIW. I see you live in the midwest. We likely share similar seasonal temperatures.

 

[[email protected]]

Originally Posted By: Doog
what about in the Winter when it is below 32F?


Well, I'd be plugging in my block heater but we've already experienced temperatures in the 20's down here in Metro Detroit and I spent a weekend at the cabin (Grayling area, Mi.) where it was 6f overnight. Still works as designed. Given, not as well but lets face it, any engine coolant temp increase off of yesterdays heated coolant that would've cooled and went to waste, is pretty clever!

 

[Shannow]

Originally Posted By: Doog
Before we all start jerking over this revolutionary design, how long does this coolant retain heat over 40F when the ambient temperature is below 32F? Just wondering.

While you are wondering, it's obviously longer than engines without this feature...by a long shot...so what's your point ?

 

[Doog]

Originally Posted By: [email protected]
Originally Posted By: Doog
what about in the Winter when it is below 32F?


Well, I'd be plugging in my block heater but we've already experienced temperatures in the 20's down here in Metro Detroit and I spent a weekend at the cabin (Grayling area, Mi.) where it was 6f overnight. Still works as designed. Given, not as well but lets face it, any engine coolant temp increase off of yesterdays heated coolant that would've cooled and went to waste, is pretty clever!


You know your block heater is plugged into a coal or nuclear powered power plant right? So much for a hybrid...

 

[[email protected]]

Originally Posted By: Doog
You know your block heater is plugged into a coal or nuclear powered power plant right? So much for a hybrid...

??

Are you assuming Im some kind of tree hugger?

Did you look at my sig line? I have a boat that gets 1.5nautical mpg buddy. Not worried about any kind of footprint. 99% of hybrid drivers that Ive met arent worried about it either. They are, however, intrigued by saving gas money.

I also have a hot tub that runs off 220v, since you are keeping score over there. Omg... Im burning coal! The way I look at it, at least the coal is US mined.

Yawn.

 

[friendly_jacek]

Originally Posted By: Doog


You know your block heater is plugged into a coal or nuclear powered power plant right? So much for a hybrid...

Who cares! Coal and nuclear is made in USA, oil is not.

 

[dishdude]

Originally Posted By: friendly_jacek
Originally Posted By: Doog


You know your block heater is plugged into a coal or nuclear powered power plant right? So much for a hybrid...

Who cares! Coal and nuclear is made in USA, oil is not.


Doog has been dropping bombs in threads all night. Hopefully he'll find a Tea Party rally to attend and give us all a break.

 

[[email protected]]

Originally Posted By: dishdude
Doog has been dropping bombs in threads all night. Hopefully he'll find a Tea Party rally to attend and give us all a break.


Haha. The FUD rhetoric gets old after a while too.

Anyways, lets not let him get us OT too much. I am kind of interested to see if any of other Prius (2004-2009) owners have monitored their ICE temps with a scan gauge or some other scan tool and what kind of increase do you see when your CHRS operates?

I generally get about an 80 degree ICE temperature increase each cold start....