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Discussion Starter #1 (Edited)
The graph below is a fairly accurate representation of the thermal management system in an 06 Ridgeline.

1stTempChart.jpg

EDIT: Reposting resized chart

This graph was generated after logging data from short trip, bringing under hood temperatures to normal levels in a "bone stock" daily driven 2006 RL. (Bone stock = OEM Denso radiator)

As shown in the graph, we observe the running temperatures of:
- Engine coolant leaving the block, destined for the radiator.
- Coolant returning from the radiator to the block.
- Trans fluid entering and exiting the OTW trans cooler.
- Trans fluid entering and exiting the OTA trans cooler.
- Engine compartment ambient air.

Interesting, huh?

It's a safe guess you are questioning how this data was collected - and by extension, how accurate it might be.

Fair question(s).

Before explaining the test configuration, a quick description of an error in this data: the digital hardware used to probe temperatures have "addresses" stored in resident ROM. When initially configuring a network like the one described below, the first step in set up is: identify the unique address of each probe so the script running data logging can report the location of the probe. In support of that effort, multi-colored heat shrink was applied to the tail of each device. A map was then created to assign the probe color to a physical location, then each probe was connected one-at-a-time to the development board where its address and color were logged in a spreadsheet - as you'll see below.

This first pass chart reveals one of two problems with the data. As you may be able to see in the chart, the measured temp (supposedly) gathered at the hose connecting the OTA and OTW trans coolers is higher than the values measured at the send/return ports of those devices. Obviously, the fluid passing between these components cannot be hotter than the fluid on either side of them because there is no heat source to make that happen.

This means:
a) I flubbed the color coding/ROM address recording, OR
b) one of the probes is WAY out of alignment.
If a) turns out to be true, this means TWO probed locations are out of line. And that means understanding the effect of components of the trans cooling circuit is not yet available.

There's an easy way to detect which problem might be happening here, but I'm about to hop on a plane for a week long business trip, so diagnosing the root of this issue will have to wait for a couple weekends. Currently, the assumption is: I flubbed the color coding/ROM addressing. We'll find out soon enough.

Also note: the graph is the result of approximately 4 minutes of logging when the vehicle was operating at normal temps. After more tweaking on the script used to poll the probes, temperature "rise time" at each probe location will be logged and further data analysis will occur.

Following is a description of the test configuration used to gather this data.

Hardware/SW:
Vktech DS18b20 Waterproof Temperature Transmitters (5 total)
LANMU® UNO R3 Atmega328p/16u2
Arduino SW version: 1.0.5
Custom OneWire script for Maxim/Dallas digital temp sensors
(Note, in Arduino land: "scripts" are refered to as "sketches".

The temperature "transmitters" (hereafter referred to as: "probes") are affixed to fluid hoses according to diagrams below:

Slide1.jpg
Slide2.jpg

Graph trace labeled "Underhood" is captured via a probe mounted in "free air". It's location shown in this image:

Ambient.jpg

Methodology:
Because these probes are surface mounted, thermo-coupling is a significant consideration. Three elements were considered here:
- maximum conduction from mounting surface to probe.
- rejection of external thermal influences on the probe.
- probes attached to "like" surfaces. In other words, all rubber or all metal - not a combo of the two.

To the degree that similar surface compositions predictably conduct heat, and because they are readily accessible, fluid hoses were chosen.

Each probe is wrapped in radiant/reflective closed cell foam core/double sided aluminum heat shield. The idea is to contain heat generated by fluids passing thru the hose - "concentrating" heat into the probe (so-to-speak) while simultaneously isolating the external environment influence on measured values. Each wrap was closed using aluminum tape and further affixed with a wire tie.

Probes shown in their mounted locations:

HoseAHoseB.jpg
OTAOTWTrans.jpg

Continued...
 

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Discussion Starter #2 (Edited)
To the extent this methodology effectively captures temperature characteristics of the intended targets, concern over probe accuracy enters the equation. Info on that:

DS18b20 probes are spec'd @:
Operating temperature range: -55°C - +125°C (-67°F - +257°F)
Accuracy over the range of -10°C to +85°C: ±0.5°C

The spec above is a direct quote published by sensor OEM: Maxim/Dallas. Operating range is quite wide, the upper end aligning nicely with typical automotive transmission/engine operation. Of particular interest is sensor accuracy spec. I was curious why Celsius was listed & Fahrenheit seemed specifically omitted. I've yet to adopt mental conversions, web services to the rescue:

-10°C to +85°C / ±0.5°C converts to 14°F to 185°F / ±32.9°F

In all likely hood, the spec published by Maxim/Dallas originates from a VERY large number of devices. While the swing is real, "out-of-the box" device-to-device variance is likely much tighter than spec. Here's a graph from the MDS:

DS_Graph.png

The reason accuracy is published in narrow band (context: narrow compared to overall operating range) is: above and below 14 to 185°F, accuracy swings wider. Which is concerning to any project seeking comparative data.

Within the specified range, we have a potential ±19.3% swing!
One might conclude that - in raw form - these are not lab grade sensors. With that said, typical analog thermistors found throughout many (or most) automotive systems *may* fall into this range as well. Accuracy and dimensional tolerance of any component comes at a cost, and "good enough" often rules decisions made when product designers operate within a budget, so, as is true with everything else used in automotive manufacturing analog thermistors may - or may not be - "more accurate" than digital sensors. But I digress...

There are methods to individually calibrate digital sensors. With neither the tools to generate heat tp precise levels, nor calibrated measurement devices to verify reported results, I'll trust that the published spec is "worst case scenario" and opt to observe available data in stock form.

In order to satisfy personal curiosity about accuracy variance, a consumer level infrared scanner was used to measure the surface temp of a probe "in free air while running the OneWire sketch. The results were with 1/2 degree of each other.


With that info, it must be acknowledged that the infrared device has its own calibration and measurement errors, but geek momentum hasta stop somewhere and this is where I draw that line. This is my personal "good enough" line in the sand.

Another base line for accuracy: the same infrared scan was used to probe surface temps at each location prior to start up of the first test. Measured values reported by the network closely aligned (±0.5°F) with the infrared scan. I'm satisfied that @ 50°F, the probes are accurate.

Knowing this (and similar) project(s) will have both known and unknown variables stemming from components, methodology and human error, this project was not intended to measure absolute temperature at each probed location, rather, the goal is to measure the delta between each probed location, creating a meaningful "map" of the thermal activity in each component responsible for thermal management.

Another goal is to measure thermal performance in "stock" configuration compared a change to an aftermarket radiator/OTW assembly (in my case, replacing OEM Denso with aftermarket OSC).
That may not be a totally fair comparison because the OEM configuration has 114K on the clock.

In regards to pre rad swap test config, the 06 is up to date with service, having:
- (3) recent DIY D&F of trans fluid (recent = less than 3K ago)
- A shop supplied engine coolant change out approx. 16K ago. Depth of that procedure is unknown and questionable based on poor experience with that particular shop. Visually, fluid appears "OK".
- Engine oil is @ 30%.
- Air filter changed 3K ago.

The OSC aftermarket rad will be installed in the near future (later this month). At that time, she'll get another trans D&F and engine coolant exchange per FSM using OEM fluids. Test results to be posted upon completion. Personally, I don't expect significant deltas between pre/post swap out measurements, but we'll see.

Quick mention:
"OneWire" protocol doesn't literally mean One Wire. There are three wires required for each probe. They are:
- data
- 5VDC +
- 5VDC -
Each Maxim/Dallas chip has a unique "address" stored in ROM, as such, they identify themselves in polling by their unique address. This makes possible "one wire" (data) termination @ the UNO board. So... the 9 wires coming from 3 probes located @ the bottom of the rad are joined to a 3 conductor cable. 6 wires coming from the 2 probes located on the engine coolant send/return hoses are joined to a 3 conductor cable. The resulting 6 wire/2 cable pair run under the engine air intake throat, over/on top of the drive side wheel tub where those 6 wires join with 3 coming from the ambient probe located top of the firewall. The single/3 conductor cable now enters the grommet above and behind the brake booster where a previously installed 4 gauge cable enters the cab to power audio amps. All connection points are twisted/soldered/heat shrink wrapped. That was tedious work. FYI: a bench top/variable temp solder station operating outside, on a concrete driveway during a 50°F windy day is both physically and environmentally hostile to soldering!

That 3 conductor cable is loosely run to the front passenger seat, connecting to the Uno board which is USB connected into a laptop running the Arduino application.

The work done here is temporary in the sense that when measurements are completed, probes and wiring will be removed. It simply isn't practical to operate a daily driver with a lap top in the passenger seat. And I'm not going the route of a Jotto Desk or car PC. At least not yet. Although I have long romanced the idea of a car PC, but that's another story.

The goal of this project is to assist in understanding thermal behavior during "warm up" and provide (what should be) expected behavior under normal driving conditions. I would be interested in seeing what happens when the truck is loaded somewhere close to max_pay_load but not sure I have the means to accomplish that. I'd also like to see real world measurements under various climate conditions, so I may leave the network in place long enough to gather data in mountain snow and San Diego summer conditions.

None of the wiring was routed with the intention of being permanent. Nor were probes affixed to their assigned locations with permanence in mind. Having said that, if anyone has ideas on other locations to be monitored, I have several spare probes sitting around. If I can work up the gumption to tackle more soldering/cabling, perhaps an interesting project could be added to the future.

Other than conceptualizing a method for thermos-coupling, none of this was invented here. All that was required to put this together was an investment in researching available off-the-shelf solutions and a bit of physical effort.

Credit goes to:
ROC forum member Carsmak for squaring me up on probe locations. I had the idea of overkill, his perspective injected a large dose of reality to the project.

One Wire "sketch" authors from around the globe. These are the geeks that make all kinds of things possible for people seeking knowledge on any number of interests.

Arduino for making development boards available to hobbyists seeking knowledge.

"http://www.tweaking4all.com" for authoring an article putting these resources together in a way making it possible for dopes like me to pull of a project like this.

Reference material authors creating calibration techniques such as: https://edwardmallon.wordpress.com/2015/03/30/using-ds18b20-one-wire-sensors-to-make-a-diy-thermistor-string-pt-2-calibration/

I hope someone finds value in this data. I found it personally rewarding to put together.
 

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Discussion Starter #4 (Edited)
Probes and Arduino development board:

Probes.jpg

Arduino.jpg

A bit more info on comparing probes hot/cold to infrared. OBD temp report from the Torque app for reference.

CalColdHot.jpg
CalColdHotOBD.jpg

IMO: this info correlates accuracy sufficiently. I'm confident the digital devices are aligned to tight tolerance for the purpose of understanding the effects of heat management under the RL hood.

Looking forward to solving the snafu on the OTW/OTA thing.
 

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Wow, quite a lot of work, and I know that one probe issue is going to bother, you.
 

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Discussion Starter #6
Wow, quite a lot of work, and I know that one probe issue is going to bother, you.
After a quick visual confirmation, probe color/location correlates with the diagram generated when ROM addresses were captured. So unless I really blew the import of addresses to the chart, measured results are a mystery.

When time is available, I'll unwrap probes on the trans fluid lines and use a heat gun to ensure addresses are correct.

Crazy part about the error is THIS is exactly what I was seeking: a better understanding of the effects both OTA and OTW coolers play on fluid leaving & returning to the trans. I hate making stupid mistakes!
 

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Great work Pat. Very impressive.
 

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This is very interesting. I agree with you on the OTA/OTW data feed -- it should be tracking with the other two ATF feeds and it's not. I have confidence that you'll find the error there. Best of luck on your business trip, and I'm sure we all look forward to seeing what you find when you get back.
 

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Thanks for all the hard work! I am particularly looking forward to any warm up data that you generate from this setup. One issue is that San Diego is not going to provide you with much real cold weather data. Planning a trip to the mountains any time soon?
Thanks again!
 

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Discussion Starter #10 (Edited)
Thanks guys for the comments.
Hokie: I'm more than willing to let the data tell the story, and it bothers the chit out of me there is an error in the system - so I'll definitely run that issue to ground. I'm actually thinking this problem offers a yet-to-be-considered opportunity. Using a heat gun on ONE probe while the Arduino script is running will definitely reveal where the problem lies, but what about measuring "isolation" of the "closed cell foam/double sided ALU radiant heat deflector? Two aviaries/one test is what I'm thinking. :) Leave a probe wrapped, heat the outside, see results then un-wrap it - repeat and see results. Cool thing is: Arduino script can run while vehicle is OFF, so temp +/- can be logged under each scenario.

I have no idea if anyone is following this. But geek-momentum overrides that concern. :)

In the meantime, sitting on a 5 hour plane flight thinking about this issue made me nuts. I broke out the computer and stared at the numbers. Here's what I came up with:
1) Naming conventions specifically labeling probes with locations like "engine block coolant output" and "trans fluid output line" were intentionally avoided. The idea was throw out assumptions, any assumption, and let heat tell the story of what-is-happening-where.
2) Fair effort was put into verifying the accuracy of these 5 probes. It looks to me they ARE. So an out-or-spec probe is off the list of potential problems.
3) That leaves location/color coding/ROM addressing at the root of the issue.

With those things in mind: looking at the #'s, it occurs to me heat SOURCES are easily identifiable in flow of fluids. For example: Coolant is heated by the block, sent to the Rad to be cooled before being returned to the block. Can I get a DUH? So we can measure fluid temps and safely assume hotter is send and cooler is return.

In a vehicle operating at temperature, its safe to assume fluid leaving the trans to be treated externally before returning is warmer on the way out than the way back in.

SO: if we flip probe address #’s labeled “OTA/Trans” and “OTA/OTW” and change labels based on WHERE heat is coming from, look what happens:

ProbeChange.jpg

Here's what overlaying one row of numbers on an FSM image looks like:

FixProbeLocal.jpg

No comment from me. What do you guys think?

eurban: I too am VERY interested in temp rise time in other ambient environments. A trip to the snow, overnight stay to let thing cool all the way down followed by a timed log is most definitely coming in the very near future. Carsmak tells me its been way down in the low double digits up in the Big Bear area. Might be time to take the little lady for a ride and cabin stay. For the purpose of gathering data, of course. Temp rise times is another way of understanding the effects of OTA & OTW on trans fluid. And hyper cold weather should make that stand out like frost bitten finger.
 

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Very nice work!!

I must have recalled incorrectly. I thought it was said that ATF was sent to the OTA cooler first, then to the OTW heat exchanger second. Guess not(?)
 

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Discussion Starter #12
Very nice work!!

I must have recalled incorrectly. I thought it was said that ATF was sent to the OTA cooler first, then to the OTW heat exchanger second. Guess not(?)
Popular knowledge agrees with your thought. That was mine as well. We'll see...
 

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I don't think the last graphic (with temperatures on the radiator image) is correct, assuming we're still working with the same data. I can accept that the fluid leaving the transmission is ~140 deg F. Then it flows through the radiator's heat exchanger, which is surrounded by ~160 deg F coolant, and emerges at ~100 deg F?
 

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Discussion Starter #15 (Edited)
I don't think the last graphic (with temperatures on the radiator image) is correct, assuming we're still working with the same data. I can accept that the fluid leaving the transmission is ~140 deg F. Then it flows through the radiator's heat exchanger, which is surrounded by ~160 deg F coolant, and emerges at ~100 deg F?
Was wondering who would make that observation!

At this point, there is only one data set.

If we accept the temperature data itself is accurately captured by the probes, and forget about which probe is where, there are a limited # of conclusions to be drawn.

The spreadsheet snippet in the upper right corner of the graphic below shows 1st and last data columns in the data set.

The final column in the data happens to be the highest measured values resulting from a short/steep climb up a hill to my neighborhood. Transferring heat values to their most likely location, this is what you get:

TempsAtProbes.jpg

How could trans fluid entering the OTW exit @ lower temp than the engine coolant its immersed in? Far as I know, that can't happen.

One of the goals behind the project is to eliminate (or greatly reduce) speculation about what is happening in heat management, yet being here I am speculating further by trying to stuff what I think into data results in order to compensate for a human error in data collection.

Again, I'm confident the probes and measurements are accurate. Aside from the question of what's happening between the OTW & OTA, the effectiveness of the engine coolant seems weak. But then again - we don't know what we don't know, so perhaps a 5 to 14% temp reduction is "normal" while the trans circuit enjoys 24 to 42% reduction?


Cooler_Effect_1.jpg
EffectLowHigh.jpg

EDIT: (since we are entering deep into the world of speculation - end edit) For the moment, no more analysis on these numbers until the remaining questions about probe locations can be resolved.
 

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Even if you flip the fluid flow direction (based on FSM label "ATF Cooler Outlet") so that hose is actually feeding the transmission, that would mean the transmission itself is dropping the temp from 141F to 81F. There's no way that can be true - even if you posit that it's presence in the airflow under the vehicle allows for cooling effects, it's proximity to the engine and exhaust would make that implausible.

Yeah, there's something else wonky.

Chip H.
 

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Very Nice work OhSix!

I think your numbers reflect flow and I think the FSM is a typo as the page before list that point as cooler inlet. (In the cooler flushing section)

A lot could probably be deducted from radiator efficiency also in reflect of the in/out temps.
I figure our radiators are single pass.
Food for thought...
.
 

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Discussion Starter #18
Even if you flip the fluid flow direction (based on FSM label "ATF Cooler Outlet") so that hose is actually feeding the transmission, that would mean the transmission itself is dropping the temp from 141F to 81F. There's no way that can be true - even if you posit that it's presence in the airflow under the vehicle allows for cooling effects, it's proximity to the engine and exhaust would make that implausible.

Yeah, there's something else wonky.

Chip H.
Without being able to lay hands on the probes to (re)verify addresses, color codes and locations, the best conclusion now is I REALLY screwed up the recording of those things, and the resulting temp values are completely whacked in their (now) assumed locations - thereby throwing them out.

Having said that, the procedure used to put that information together is pretty straight forward. Running the script with a single pre-color coded probe connected to the Lamu/Arduino board - and copy/pasting the alpha/numeric addresses reported by the script - along with the corresponding color code into a spreadsheet, then transferring each of those to engine drawings taken from the FSM. With that done, the diagrams were used as a guide to physically attach each probe in their assigned location. I'm more than open to accepting I totally whacked that process but rewinding the video in my head of doing that, it is a difficult pill to swallow. Especially in light of knowing the probe colors are - indeed - placed in their assigned places.

Evidence.jpg

So.... verification is the only way to end speculation of what-went-wrong-where.
 

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Discussion Starter #19
Very Nice work OhSix!

I think your numbers reflect flow and I think the FSM is a typo as the page before list that point as cooler inlet. (In the cooler flushing section)

A lot could probably be deducted from radiator efficiency also in reflect of the in/out temps.
I figure our radiators are single pass.
Food for thought...
.
Thanks skelly. Yessiree, our radiators are single pass. Here's a couple links to tear downs of radiators you might find interesting.

Anatomy of a Denso radiator
http://www.ridgelineownersclub.com/forums/showthread.php?t=116753

Radiator comparison: Denso/Spectra/OSC
http://www.ridgelineownersclub.com/forums/showthread.php?t=123033
 

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Yes, our radiators are single pass. As are our internal and external transmission coolers. Our power steering coolers, I suppose you could say, are dual pass.

Number of passes can be misleading. It's really parallel flow vs. serial flow. Does the fluid flow in a straight line through the system, or does it split up and take multiple routes through the system?

This is the external cooler set up I have on our 2005 MDX:



You could say that the power steering cooler (on the left) is a "four pass" cooler, while the ATF cooler (on the right) is a "single pass" cooler. From that, you could infer that the more passes, the better. To the contrary, it's usually backwards -- serial flow coolers are generally not as efficient as parallel flow coolers. My power steering cooler is a serial flow cooler, and my ATF cooler is a parallel flow cooler. I patterned it off what Honda put on the Ridgeline as factory equipment.

More passes are better only if you're comparing two serial flow coolers. A two pass cooler, just one loop out and back, would be less efficient as a similar design four pass cooler, with two loops out and back (everything else being equal, like pipe and fin size, etc).
 
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