I should have something in the morning. I've performed warm-up tests using "N" and "P"and will conduct a block and transaxle heater test Saturday morning using "P".

Bob Wilson

 

Were you able to perform the tests this weekend?

 

I did but posted the results in the General area thinking that block heaters probably work for all makes and models:

https://www.greenhybrid.com/discuss/...25&postcount=1

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.

UNEXPECTED CONSEQUENCES: This morning the temperature was 85F with high humidity. So I unplugged the block heater drove off and turned on the AC to take out the humidity and moderate the heat. The block heater fuel savings made using the AC quite reasonable during the summer.

Bob Wilson

 

Thanks Bob!

 

Hi Battery Buddies - re: Block Heaters... We used to have them on all the old cars (I'm talking 1954 Plymouth 6Volt Battery) in Bozeman @ 32 below - plugged in right at the Parking Meter, or you are walking home, friend. But I have had good luck with all my modern cars - in the garage or even in the Car Port where I live now - with a 100w drop light slid under the engine/tranny and an old blanket thrown over - big enough to cover the wheel openings and down over the radiator. I'll sure do that with my 'Battery Betty' this winter. No direct connect to the engine, but still, breaks that winter chill on 1st start.

 

Don't waste gas . Drive to warm up. So what you get 23 MPG during warm up. If you sit still you get 0 MPG bring down average. ICE works better on medium throttle, very bad at low RPM.

Drive it. My Prius warms up in 3 to 5 minutes. Most people's first few minutes of commute would be in slow traffic. During this period, I can't glide anyway.

 

Hi all! New prius owner here. I just sold my 08 FEH and got a prius. I hope it will be here by the end of next week. (being shipped from Calif) anyway i am going to do this block heater mod as it looks pretty straight forward, wanted to let you guys know I bought mine online at a toyota parts store for $30 with $7 shipping. No sales tax i used the US part number that i found in this thread. Just thought you might like to know they seem to be available.