Discussion in 'Articles' started by msantos, Nov 20, 2008.
Most Excellent, as usual.
I blocked the top first because I was going out of town for the weekend. I blocked only the top to start with. It scared me a little as the ScanGauge said I went to 210 degrees F (99 C). This was peak. It stayed in the 200+ range though. However, when checking the temp on the main panel it was in the center. For the return trip I removed the blocks and saw the same temp's. The ambient was about 40-45 deg F in light rain both times.
I will follow your advice and start with the bottom this time as my normal commute is all city streets.
Do you think my ScanGauge is giving optimistic temps? What else could be causing this? Are these slightly higher temperatures a problem?
Your article is great. Just want to be sure I am not causing myself any major headaches later!
BTW, it appears that the goal would be to get into S4 as quickly as possible.
It would be great to have a set of motorized shutters to make this happen.
The ScanGauge temp readings are very realistic and pretty accurate. This is because the ScanGauge simply "reads" and "displays" the actual temperature values broadcast by the car's ECU.
Over the long haul you'll want to avoid very high temps. The short little stint now and then should not hurt too much.
Anyway, as we said many times before, the built-in engine temp gauge is the least accurate and often the least useful for folks like us.
Agreed... as long as the mechanism does not freeze and lockup after coming out of a car wash in a -30F winter day.
You wash a car on a -30 day
For that matter, a -30 degree day
-30C is about -22F... I've washed my Insight at -12F simply because the windows had a film (tried to clean them with Windex -- never again!!! ) and the windshield washer nozzles were frozen shut. The wash fixed both issues and applied a film of RainX in the process.
I've been wondering about using some of those rubber blanket
heaters to gently warm hybrid *batteries* and get them to their
happy operating temps sooner, as a companion effort to using
an EBH. It would probably have to be mounted under the battery
box, involving pulling it out, and making sure no part of the
box would crush the heater, etc etc. Possibly easier in Honda
variants since the Prius pack tends to be a bit heavier, and you
probably wouldn't want much more than a heating pad's worth of
power -- 50 or 100 watts, to avoid cookin' 'em, esp. without
some kind of thermal feedback.
It would make a great addition to an OEM plug-in rig...
Holy macro. That is an awesome idea Al.
You know, I never really thought much about that but now that you mention it I see quite a bit of merit to such a project. You are right, at first it would seem easier on the HCH-II but perhaps not because of the weight (believe it or not they are closer in weight than we think)... but instead I would see it as a very rare packaging advantage for the HCH-II.
Placing the pad right on the IPU sturdy metal cover would not only heat the entire IPU (gently but surely, where the pack and the other temp sensitive hybrid control modules are) but also radiate a good amount of heat into the passenger cabin without any major dangers or overheating. All this would happen while the block heater is keeping the Stator/Motor reasonably warm and ready. Hummm
At first thought, the way I would approach this is to use a high current diode in the pad's power line so that the wattage is cut in half... or a wall switch style AC potentiometer to help dial in the power level feeding the pad. The power line would then join in with the EBH cord. Plugging in the EBH would mean plugging in the pad as well.
On second though and unless I am missing something, I can't see why this would be any harder on the Prius-II either. hummm...
By looking here we see quite a few models that would make the cut in this application. The 50 Watt unit ($50) has a very small contact area and that concerns me a bit. However, the "battery heater" model ($40) may provide a bit of gentle heat - enough to work well on the entire Prius battery enclosure or the HCH-II IPU enclosure. Check out their thermostat. For $20 it would do well in preventing overheating.
Randall made mention of an "IMA Battery heater" back in 01/2007... might be worthwhile finding out what he did for his Insight?
Seems so to me as well. Could you not just stick one or two on the back of the bracket that surrounds the battery? It is easily accessed when the false floor is out and wouldn't involve ANY weight on the pads. Wouldn't warm as directly as if the battery was sitting on them but it would be quick and easy. Some of that heat would also seep over to the 12V and keep it as well. Plus, if you cart a dog around back there, it will have a pre-warmed floor!
Thanks for all the useful info, Manuel. Who better to write this than someone from "Winterpeg" (that's Winnipeg, Manitoba to those not familiar with its common nickname).
A couple points:
I am not familiar with what "mid 3s" refers to in the HCH operational modes. I'm guessing it may be the 'lean burn' mode??
I notice that the rubber seal along the leading underside of the hood has a gap in front of the engine air intake. I assume this is intentional for warm weather conditions. It's possible that sealing the gap between the grille and the hood would feed warmer air into the intake. I remember when cars had a flap on the air intake to draw heated air off the exhaust manifold but I haven't explored the HCH intake duct to see whether it might have something similar.
You are quite right about the seal gap. Although I have not mentioned it before, I have actually covered that portion with cell foam tape: an - almost permanent - application which I peel-off for the summer.
The reason why I did not mention this before is because I am not quite done assessing the full impact that a warmer intake has on the HCH-2 FE during the colder days. I'll post some pics sometime this month after I have a "more empirical view" of its benefits.
The mid 3's is a high FE mode that places the engine consumption rate in the 3 L/100km range when operated in speeds ranging from 35km/h all the way to 65km/h. Many of us actually use this mode a lot. Mind you this is the avg FE, but in this mode you will easily see figures in the 2.2-3.9 l/100km range. This mode only occurs in stage S4... although I've had people telling me that they got it in S3... which is something I have yet to experience.
msantos said "ScanGauge device. It not only displays the engine coolant temperatures but also the intake temperatures which can help us determine the proper amount of grille blocking to perform."
I monitor coolant temp with a ScanGauge in a Prius. What is a good range for intake air temps? What is too High?
I honestly don't know all the details yet. From the observations I made thus far and also from the input we get from many other owners, it appears that the intake air temp plays the smallest of roles and is often not regarded as the "low hanging fruit" many of us are looking for.
Honestly, I don't know what is too high in terms of air intake temp. The technical literature I have access to does not have any details on this. I would surmise that if there was ever a risk of reaching a high temp level then that would likely occur in the hotter summer months (?) ... and even then, I am sure there would be other aspects of the system that would experience thermal failure before the upstream combustion process falters.
I'll speak from data collected with my Civic.
Mileage increases almost linearly with ambient (and intake) temperature, up to about 75 F. Above that, up to 100+ degrees, it's nearly level.
Thanks to msantos and the PaleMelanesian for your responses.
I'm getting hit with a battery recharge in nearly the same place every single day. I make sure the battery is full or nearly full by the time I get home for work. Because of the hills and the cold (down to 23 this morning) the car is very assist happy with no regen. This knocks the battery down to 5 may be 6 pips when I get to work. So when I leave work I have to climb a couple of more inclines and down the battery goes. This has happened everyday. Can't wait for the warmer weather.
Have you tried shifting to "sport mode" or "second 'gear'" for just a moment or the duration of that climb and feathered the pedal to keep it out of the pack?
Yeah, I've used the "S" mode a couple of times. It always seems to put some drain on the IMA pack. I did try it today going down an incline to a red light after just leaving work. That's usually when the recharge happens. I've tried the "S" mode one other time going up a hill, but the rpms shoot straight up to 2500 - 3000. I don't like that, so I never really use it.
No recharge today. I imagine it was the warmer temps, (mid 50's).
I bought an OEM car cover and I've yet to scrape the windows since I got it, even with temps down in the low 20's.
Kacey's suggestion has some merit especially if you use the S mode strategically - or as he said - "for just a moment or the duration of that climb".
Look at it this way:
As a negative, the RPMS go up and that disturbs the mostly quietly and serene drive the HCH-II affords. But the extra power produced by the higher RPMS during those "brief" times is also not all wasted.
On top of that, you often get a small energy surplus always diverted to the pack in the form of a micro-regen when feathering in S. But even when you don't get that regen because you need more power, the level of assist used is always less than the assist you would use when driving in "D" and that may be the key to enduring the climb without depleeting the pack at all.
On longer climbs you will deplete the pack for sure and there's nothing we can do about it other that to take advantage of whatever other opportunities you can control.
In any case, you lose some FE by using the S mode but the extra energy produced by a slightly higher reviing engine is still more efficient than the costlier to replace assist energy. If you were to get ALL your regens while going downhilll then, Yes... use the assist going uphill. But if a good deal of your regens come mainly from a forced regen, then the "S" mode is still more effective due to lower energy conversions losses you have to deal with.
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