Hi folks,

I've posted this warm-up data in the General area because block heating should help any hybrid. It is especially useful for Toyota systems but it should help all hybrids with an auto-stop capability.

I have been recording the first warm-up: (1) using "N" while parked, (2) "D" while parked, and (3) "P" after using the block heater. The battery current scale is on the right and the air mass flow data in grams per second on the left. I've offset the zero scales so the upper battery currents are separate from the lower air flow data:


This is a North American NHW11, 03 Prius that has the HC emission system and extended warm-up. The chart shows the block heater is especially useful for my NHW11 03 Prius. The data suggests:

1) ~80 grams / 2.81 oz - "D" stationary
2) ~78 grams / 2.76 oz - "N" stationary
3) ~26 grams / 0.92 oz - "P" with block heater, stationary

Although "N" had slightly less fuel burned compared to "D", "N" defeats the auto-stop. For "N" to be useful, it needs a timer, say 60 seconds, before flipping over to "P" or "D". But the quantity of fuel saved does not justify the savings when stationary. Worse, "N" does not come even close to the block heater savings.

Remember, this is a 2001-03, North American Prius, with the HC system. European and Japanese versions will not have the same "D" warm-up cycle. I don't have data for other hybrids however I suspect they would also benefit.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

In the future could you label things by color in the graph?
I think I get it, but It took a while to figure out.

Green =
Red =
Blue =

and so on.

So are you saying you went to EV mode in about 86 seconds when using the block heater? I'm really curious what this would be like on a 0 degree night.
You could get similar results, but will probably have to pay for more energy to run the block heater for more hours in winter. Don't you think?

So I can imagine the gas savings.
What about the cost savings?
CO2 savings if you consider the power plant?

Thanks for doing an experiment I've always wanted to do.
( But I still don't have a block heater, but think I can get one for about $120. ) OTOH, how much gas would I need to save to get my $120 bucks back! Catch-22 as they say. ( I know they say that, but I don't even know what catch-22 comes from! )

Thanks for posting.
-John

From the book (and movie) Catch-22:

http://www.imdb.com/title/tt0065528/quotes

Exactly versus more than 5 minutes in "D" and never stopping in "N". Preheating in "P" makes a significant improvement.

If that is 0C, I might have some data in about six months. But if that is 0F, I live in North Alabama.

As for cost, my Prius block heater is about 400W. Ken@Japan reports the electrical cost is half of the gas savings. That pretty well agrees with our rates in N. Alabama too. However, this is only the warm-up idle savings. The big bucks comes from entering hybrid mode so much sooner on the road.

JC Whitney has an oil pan heater, 125W, that you apply to bottom of the pan. I've got one on my transaxle oil pan and it seems to be fairly effective in warming up that block of oil and metal. I remember the JC Whitney part is relatively affordable and I thought it came in two sizes.


Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

Alabama winters are not too cold I imagine.
What about a HV battery warmer?
Or have you added that already too!
-thanks
Always enjoy your posts.
This thread is top notch.
-John

I've been thinking about it but for now, I'm planning a 'tickle charger' to bring the SOC to 78% by morning. With a warm block, warm transaxle and topped off battery, my morning commute, even in cold weather, should be pretty good.

If I find evidence of cold-battery induced, fuel burn, I'll look at how to approach the problem. There are off-the-shelf, lead-acid battery warmers that could fit around the case. Alternatively, a 'hair dryer' could be used (I hate this solution!) But my studies to date indicate our fuel economy is not a strong function of the battery as long as it meets a minimum power threshold.

Most of the time, the ICE is generating the power needed and the battery just fills in the short but intense gaps. We really aren't driving an electric vehicle but rather a gas vehicle that uses electricity to keep the ICE operation efficient. That is one reason why I follow but am not desperately looking for the plug-in Prius.

I would rather see a turbo-alternator and other exhaust heat engines than a plug-in Prius. This will help us get maximum utility for the dollars burnt.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

The battery shape in the Ford is thin and flat and about 3 feet square, and only about 4 or 5 inches deep. I thought an electric blanket would be a good solution for this, but I don't know the shape of yours.

What about a thermocouple device for the exhaust?

One problem in the ethanol production industry is:
Yeast make heat. Lots of heat.
So much, you must artificially cool the brew, otherwise they will cook themselves to death in just a few hours. We use evaporative cooling towers... swamp coolers to do this... and expend millions of btu to the atmosphere each hour.
Then, on the other end of the plant, you need to burn fuel to heat the brew, to distill the ethanol. We literally have 2 million gallons of 93'F brew on one end, and need only 100 gallons per minute of 180'F brew on the other end.

Seems to me there should be a way to convert Millions of gallons of 93'F "water" to a few hundred gallons of 180'F "water" without the use of fuel.
Any ideas?
Other than that, I also thought some sort of thermocouple device could help chill the 93'F brew, ( less demand on cooling tower ) and make some electricity to run plant motors at the same time.
Kind of like you could use a thermocouple on your tailpipe to make electricity for your hybrid, but it may be a trivial amount. ( probably )

Bob,

Any thoughts on how this block heater http://www.jcwhitney.com/autoparts/P...t=block+heater would do? Seems like a simple way to use a block heater, while keeping it portable, and it is only $50.

Think of coming home after driving through slush, salted streets and you're home and the crud is dripping off the car . . . now to put on the block heater. There is a lot to be said for not getting under the car in bad weather for any reason.

You might look at this product:
http://www.jcwhitney.com/autoparts/S...&searchbtn.y=0

It comes in two sizes and the smaller one fits my NHW11, 03 Prius transaxle pan. The larger one would easily fit on the ICE oil pan. It would take one day to install, let it cure over night, and you're done.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

Thanks Bob. I have been looking for detailed info as opposed to hearsay. The graph says it all, but I do have a couple of questions. Do you have data for the "P" mode without the engine block heater? Also, what was the temperature that morning?

In regard to your first comment, I was seriously hoping Toyota would provide a charger to do exactly as you say, ie. bring the SOC back to acceptable level. But I have finally given up on that hope. Please post when you have more info. Thanks.

I agree with your other comment ...but if you can keep your speed to under a threshold (42 miles per hour?), you can run on EV mode only. It is my understanding that the plugin will run at higher miles per hour without the ICE kicking in. If so, that can significantly increase efficiency for short distance driving. In effect that makes it an EV. Yes no? Thanks, JJ