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Discussion Starter #41
When you mash the throttle, the drive-train computer(s) have to decide whether it is better to leave the ICE connected, contributing its torque at 2,000 rpm or so, or disconnect it, so that maximum electrical power can instead be fed to the traction motor, with the ICE revving up. RinconVTR says this is what happens (presumably by using his ears to hear the revving of the ICE, or perhaps he is using a code reader and app to actually monitor the ICE rpm). I don't doubt that he is correct in this. It may also be true that under less-than full-throttle acceleration, the computer(s) decide that it is sufficient to leave the ICE connected.

l
Not a bad write up. And yes, I am correct, I don't know why there's so much doubt. It takes only one drive to listen to the gas engines behavior, but I also use a scan tool. OBD Fusion.


Direct Lock up clutch is only engages as "low load", and I described this clutch engagement/disengagement as "sensitive".

Honda's documentation indeed confirms, it activates at only at "high speed and low load".

Add to that, when the load is very low at high speed (55-75+), EV mode often activates and I have noted this is not discussed/mentioned anywhere that I could find.


 

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Worried about my Third Party Warranty Plan now...
Does the Honda Limited Warranty refer to "it" as the Hybrid Powertrain?
At this point, I want to make sure I have a comprehensive enough plan. I advised Assurant (3rd party warranty company) that the my vehicle does not have a transmission, because that's what my salesman told me.
I suppose I can call Assurant for clarification and to make sure I have coverage for the Hybrid Powertrain and/or transmission.
Thanks for bringing up this topic...and for everyone's insight.
Happy Holidays.
Can't comment on 3rd party coverage, but HondaCare covers it. And a lot is covered under the Fed's 8 year/100mile warrenty for Hybrids and Electric cars.


Underneath the "Hybrid Battery" line items, says "HYBRID TRANSMISSION ASSEMBLY"






Does it say that for the 2018 model year Emissions Warranty as well? Or, is there a completely separate section for the Transmission parts?
 

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Discussion Starter #43
Does it say that for the 2018 model year Emissions Warranty as well? Or, is there a completely separate section for the Transmission parts?
I just looked and there is a new doc for 2018 in my owner account. (The 2017 version was the only one available just last week.)

The 18 version is broken out in much greater detail and more than one page is dedicated to the Hybrid alone.

And honestly there's much less direct use of the term "transmission", but its still there.
 

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Does it say that for the 2018 model year Emissions Warranty as well? Or, is there a completely separate section for the Transmission parts?
I just looked and there is a new doc for 2018 in my owner account. (The 2017 version was the only one available just last week.)

The 18 version is broken out in much greater detail and more than one page is dedicated to the Hybrid alone.

And honestly there's much less direct use of the term "transmission", but its still there.
I've been telling people that my car does not have a transmission. Which just sounds idiotic now...I am going to stop saying that.
 

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As ANOTHER side comment, is also my opinion that arguing about whether our cars have a transmission or not is fairly pointless, especially when "both sides" seem to mostly (OK, maybe not entirely) have the same understanding of what is going on in the drivetrain. Sort of a "you say to-MAY-to, and I say to-MAH-to" type of thing. Can't we all get along? :angel
Oh, if it were only that simple. The argument on the other side seems to be "I say to-MAY-to, and the people who think that they are saying to-MAH-to are really saying to-MAY-to incorrectly." It's hard to pin down, but that is what it seems like.

In the field of mechanics in general, a "transmission" can be the entire mechanical system that transmits power from the power plant to where it is needed. Call this "Transmission A." In automobile mechanics, that is called the "drive train" or "transmission system"; the] transmission, as a component, is just the part of that system that varies the gear ratio of the overall system. Call this "Transmission B." Anybody who refers to "the transmission" in a car means Transmission B. I'll point out that the definition RinconVTR said he follows says as much.

The i-MMD is transmission system; that is, a Transmission A. It does not have a Transmission B. Anybody who says it doesn't have a transmission, means that it doesn't have a Transmission B.

RinconVTR's argument seems to be - again, it is hard to pin him down - that there are modes where he doesn't understand completely how the power is transmitted. But since the documents use terms like "transmission fluid" and "transmission system," the parts he doesn't understand must include a "transmission." He won't say whether he thinks that means A or B, just that the people who say there isn't one can't mean Transmission B. Even though, by the definition he says he follows, that is exactly what they mean.

And yes, I am correct, I don't know why there's so much doubt.
I never said you were wrong that the car goes into serial mode at high speeds - just (A) that I've noticed no evidence of it, (B) that the passage you cited earlier, as evidence that Honda documents admits to this statement, says no such thing, and (C) that IT DOES NOT IMPLY THERE IS A TRANSMISSION B.

Direct Lock up clutch is only engages as "low load", and I described this clutch engagement/disengagement as "sensitive".
The passage you quoted earlier about "quick acceleration" contradicts this statement. Funny how you choose to take some statements out of context and then accept them as absolute truth if doing so agrees with you, but ignore the parts that explicitly contradict you in the same documents.

That earlier one says that in "Engine Drive Mode" the ICE provides power directly to the wheels through the lock-up clutch; and, if quick acceleration is needed, the motor adds additional power to it as a "parallel hybrid."

The passage you quoted here included context that you omitted, that explains how the lock-up clutch applies to high-speed in general, and in that mode the motor supplements the ICE when the load increases. Same as the earlier document.

Neither column you quoted here applies at all speeds.

Honda's documentation indeed confirms, it activates at only at "high speed and low load".
Yet there are situations it does not describe. You noted one - it can go into EV mode at high speeds, but the column to the left of the two you extracted says EV mode is used when stopped or at low speeds. And the speeds are also indicated graphically in the row above what you extracted.

What it calls "Hybrid Mode" is really "serial hybrid" mode, and the context you removed only implies that this high-load help occurs at medium speeds. What it calls "Engine Drive" is implied to apply to all high-speed driving. Part of the context you left in says it can be supplemented by the motor (parallel hybrid mode) when added propulsion (for high loads) is needed.

The 18 version is broken out in much greater detail and more than one page is dedicated to the Hybrid alone.

And honestly there's much less direct use of the term "transmission", but its still there.
Most often, by far, when discussing what it means to be in "P", "R", "N", or "D". As in "With the transmission in D..."

You do know what drive-by-wire means, right? That these buttons tell the computer how to connect Transmission A to the wheels. So it requires another definition, Transmission C.

If not Transmission C, it is talking about the transmission system, Transmission A. Like for error messages.

I've been telling people that my car does not have a transmission. Which just sounds idiotic now...I am going to stop saying that.
Most people use the definition for Transmission B. Your car does not have one. If you feel uncomfortable saying that, say "no gearbox."
 

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Discussion Starter #46
Look how long it takes to form rebuttal statements in attempt to believe the is no transmission in the Accord Hybrid. All backed by nothing.


So, when our Hybrid finally does throw a maintenance code for "transmission fluid change", how will you explain this to anyone? May be something like this;


"It's so cool my Hybrid has no transmission, but I still have to change the transmission fluid and check the level once in a while."


Reply "Is your Hybrid driven directly off an electric motor?" You answer; "Well, no. There's a bunch of gears and stuff, like a transmission, but the internet says it's not a transmission."


Normal people will give you blank stares, but you'll go on and on with the same long winded, big worded lip service. They will nod and smile.


I recommend first showing them my edited image so they immediately understand where your coming from.

 

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I will wait to see if anyone else is as confused as you Rick. Thanks for your extreme concerns.

Nope. You are very wrong and have a server lack of understanding.

I refuse to respond to all these drawn out responses
How does the understanding of how a server operates have anything to do with anything posted here?
 

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The multi-quote button is here!

How does the understanding of how a server operates have anything to do with anything posted here?
Great post Rick, it ads so much important content!

The "confusion" in this thread did not relate at all to your early concern about generational issues and such.

And thank you so much for pointing out a spelling error.

You are doing an excellent job moderating this forum, attacking members in pristine fashion.

My S2000's clutch calls for Honda DOT3 brake fluid.

Does that mean the clutch is a brake? :D
You tell me.

Do you change the brake fluid in the brake system master cylinder reservoir or the hydraulic clutch master cylinder reservoir?


My Toyota calls for ATF in for Power Steering fluid.

Does that mean I change the Power Steering fluid in the Transmission?
 

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^Perhaps if you did not begin this thread with so many gross and deliberately misleading errors, more people would believe your subsequent arguments, memes, and poorly-worded circular wiki definitions.

But keep on attacking- that is your best defense, since your arguments are shallow and pedantic.



...and thank you for the compliment! When people post false information- as you did, they get called out on it.
 

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Look how long it takes to form rebuttal statements in attempt to believe the is no transmission in the Accord Hybrid.
It actually doesn't take long to form them - they write themselves. Coming back to read what needs to be rebutted is a different story - we do have lives outside of this forum.

Yet you have not rebutted anything I have said, except for a glorified version of "Is Not!" The above quote is an example.

All backed by nothing.
By much more than you have. "IT USES TRANSMISSION FLUID, SO IT MUST BE A TRANSMISSION" is a non sequitur. And while we can't, for obvious reasons, find the part number or schematic drawing for something that does not exist, you should be able to do so if it does. Have you?

+++++

AGAIN: Any mechanical device that transmits power from where it is generated, to where it is used, can be called a transmission. Not so strangely, its moving parts are often lubricated with "transmission fluid."

But in automotive mechanics, that is called a drive train or a transmission system. When the term "transmission" is used alone, it refers to just the portion of the drive train, or transmission system, that varies the gear ratio within in the system. By anybody except you, that is. The Honda i-MMD does not have such a device, and you have provided no evidence that it does. Just non sequiturs. Nor have you replied intelligently ("not with non sequiturs") to this point for the 5 days this non-discussion has been going on.
 

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Honda's documentation indeed confirms, [the lock-up clutch] activates at only at "high speed and low load".
I took the time to reconstruct the entire table that RinconVTR refers to here. (Well, I did omit the parts about regenerative braking.) He didn't say what document, but it was easy to find in my 2018 HAH Owner's Manual It's on page 12, in the "Quick Reference Guide" section. Which means that it isn't supposed to be an exhaustive reference, something RinconVTR noticed but didn't bother to consider when he drew this incorrect conclusion.

What RinconVTR reproduced was taken out of its context, and is not what the document says. The clutch can "activate" at high speeds when the load is not low. I'm not saying that the clutch can't disengage at high speeds, because I don't know. I'm just showing how RinconVTR deliberately takes things out of context to make his point, which is often incorrect.

I did make a few alterations. I added a couple of clarifications in red - one I'm not certain about, but it is consistent with what I've observed from the power flow monitor. And I separated two modes that Honda described in a single column, into two columns. Because that is the mode RinconVTR said doesn't exist.

Contrary to what RinconVTR wants us to believe, the document says the clutch does lock up (motor provides power to the wheels) at high speeds when the load requires added propulsion.

I'm also including a graphic from the previous page (so how did RinconVTR miss it?), that indicates the major components of the i-MMD system. Note that it does not contain anything called a "transmission." And the dipstick for checking and adding transmission fluid, which is not accessible by non-mechanics, is in the part labeled "Generator and Electric Motor." So by RinconVTR's logic (in a reply to josby), using transmission fluid does not make it a transmission.

And all of this is irrelevant, because what Honda (or anybody else except RinconVTR) means when they say the HAH has no transmission, is that it has no mechanism to vary the gear ratio when the ICE propels the car. And it doesn't.
 

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Since RinconVTR seems to have given up defending his incorrect assertions, I thought I'd summarize the most critical one at the end of the thread, so that newcomers will not be confused if they start at the end.

So technically [the Honda i-MMD hybrid system, as used in the 10th gen Accord Hybrid] has a transmission, in that it has a way to directly transmit power from the engine to the wheels. But the common understanding of what a transmission is includes some means of varying the ratio between the engine speed and wheel speed, and in that sense, it does not have a transmission.
This is correct, with the clarification that the last bit should say "some means of varying the ratio between the engine speed and wheel speed when the engine is driving the wheels directly." Which is what is almost universally meant when one refers to a car's transmission.

This is the exact misconception that is all over the internet and I'm puzzled by it, because its absolutely wrong.
It is a correct concept that RinconVTR misunderstands, and so calls incorrect. He used only anecdotal evidence to support his assertion. Like "It uses transmission fluid!"

The "eCVT" does in fact, vary the ratio between the gas engine speed and wheel speed.
Not when the gas engine is driving the wheels.

The ratio of engine speed to the generator's speed, when the engine is not driving the wheels, is also fixed.

The ratio between wheel's speed and the engine/generator's speed, when the engine is not coupled to the wheels, is irrelevant. But yes, it can vary. Without a transmission, since they are not connected when this occurs.

It's also been presented in some reports that the GAS engine provides all power at highway speeds and the electric motors are not in use. Incorrect.
What those reports are trying to do is explain the most basic - that is, vastly oversimplified - functionality of the power plant. As, in "direct drive is used in situation X." Not "In situation X, only direct drive is used."

+++++

Edit: while looking for an answer to a different question, I tripped across a more complete explanation of modes in its video. It's still a cartoon-ish (i.e., oversimplified) version, but it explains at least one mode that RinconVTR thought was undocumented simply because they weren't listed in the cartoons he found.

Note that the components it lists do not include a transmission. An alternate version of that list can be seen here. In another document (so far, I only found a Japanese version), the "Generation and Drive Motors" and "Engine-linked Clutch" are collectively called the "eCVT."
 

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Discussion Starter #54
I had a unique opportunity to spend time with a local dealer "Team Lead" technician at my Honda Dealer late one evening just before Christmas. Stopping in to have them look a couple strange items and likely make an appointment, the Manager called his lead Technician to the drop off garage and ended up doing about 30 minutes of work right there and then.

Imagine what topic I brought up.

Short story, I double down on my statements and opinion that the Hybrid DOES have a transmission, it is simply not "conventional".

Ask your own questions of Honda, or simply stick with Honda's own terminology and descriptions. Not surprising, and reassuring to me...it is exactly what the techs do (and parts department...we visited him too). Until Honda changes their terms and trains their Tech's differently, I stand my ground firmly.

Thus, this is my very last post on this forum.
 

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Short story, I double down on my statements and opinion that the Hybrid DOES have a transmission, it is simply not "conventional".
You don't say what information reinforced this opinion, so there is no way to respond to you. Especially if you refuse to provide that information in the future. But there is a way to correct the misinformation you insist on spreading.

The "informative rather than short" story is:

  1. If the engine is driving the car mechanically (i.e., not through serial hybridization where the engine drives a generator, and the generated electricity drives the motor and thus the car), whether alone or assisting the electric motor, there is a single gear ratio.
  2. The part of a car's transmission system that changes the mechanically-driven gear ratio is referred to, in automotive convention, as "the transmission."
  3. The 10G Accord Hybrid does not have a device filling this conventional role. If you think that it has a device that fills the role in an unconventional manner, you are wrong. It has no such device.
  4. The electric motor can drive the car without this mechanical assistance from the engine AT ANY SPEED. But only if it can generate enough torque.
  5. But at higher speeds, even if it can theoretically generate enough torque, the power (torque*rpms) requirement is higher. So the battery may not be able to provide enough alone; it isn't that big. In this case, the ICE can be, AND IS, used in serial hybrid mode to provide more power. You won't explain your opinion well, but this seems to be what you think uses "an unconventional transmission.
  6. Like every car, the 10G Accord Hybrid does have a "transmission system."
  7. Depending on what car, the transmission can include gears, belts, axles, differentials, clutches, torque converters, and yes, a transmission. Many of those parts utilize transmission fluid, not just the transmission.

Your evidence to the contrary has been both anecdotal and superficial. It would go a long way toward ending what you perceive as a controversy, if you would just say which of my points you think is wrong, and tell us why.
 

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I sounds like there is a variation of semantics or definition of what a automotive transmission is and to that point we can probably agree to disagree. Honda doesn't call it a transmission but instead it's labeled as drive force transfer system. I say there is a transmission of power from two power sources to the wheels but without varying ratios that conventional automotive transmissions employ. I think I'll just call it a drive force transfer system (DFTS?).

Drive Force Transfer
Just like the previous model, the Accord Hybrid is not equipped with a conventional mechanical transmission. Instead, motive force transfer is accomplished through the interaction of the Accord Hybrid's gasoline engine and two electric motors. Coordinated by the IPU, this form of drive force transfer offers smooth and predictable acceleration matched with efficient low-rpm highway cruising when the gasoline engine is in operation. Gasoline engine shutdown is seamlessly integrated into the operation of the Accord Hybrid when appropriate.

The drive force transfer system operates without the need for a torque converter, mechanical pulley or belt. It instead uses two motors for driving and generating power. The system is optimally and rapidly able to control both engine and electric motor rotation in order to deliver higher fuel efficiency and quicker engine response in each driving mode.

When cruising at mid- or high-speeds in the high-efficiency range of the engine, a lock-up clutch is engaged, connecting the drive motor to the generator motor to transmit engine torque directly to the drive wheels as efficiently as possible. In EV Drive operation, when the battery-powered drive motor is used for either acceleration or regenerative braking, a clutch disengages the stopped gasoline engine from the drivetrain to eliminate efficiency loss from mechanical friction in the engine.

Improving efficiency and reducing weight and size, the drive force transfer system of the second-generation i-MMD integrates the torque limiter within the flywheel.
Source: https://hondanews.com/channels/accord/releases/2018-honda-accord-press-kit-powertrain
 

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I sounds like there is a variation of semantics or definition of what a automotive transmission is
Not really. There was one stubborn poster who refused to actually read, and accept, the definition that he said he was using. The one that said that colloquially "the term refers more specifically to the gearbox alone."

It really is quite simple. There is no such device in the Accord's i-MMD system. When context is not ignored, it is clear that this is what all the quotes and references - including yours - mean.

I say there is a transmission of power from two power sources to the wheels
And that is a technically-correct usage of the word "transmission." It refers to a process, not to a device. It can be called "transmission" or "drive force transfer." They mean the same thing, and can be used interchangeably, when applied to a process in a car.

Of course an automobile has a system to accomplish this process. Otherwise it couldn't move. Auto-Mobile = Self-Moving. Nobody has claimed otherwise, and it is a bit pedantic to point out that it exists.

That system is a collection of devices, some mechanical and some electrical, that have multiple ways to accomplish the process "transmission"="drive force transfer." NONE OF THOSE DEVICES IS WHAT IS COLLOQUALLY KNOWN AS "A TRANSMISSION".

+++++

What that poster couldn't accept - and as far as I can tell, refused to try if it didn't agree with his claim that there was a device he could call a transmission - was that the i-MMD system has a very unconventional way to accomplish the process of transmission=DFT. And that the normal way of describing the capabilities of a car with horsepower do not apply the same way that they would to a more traditional car. But Honda still needs to describe the car to the public, so they use these terms.

I'll admit that I am not an automotive engineer, but I think I have most of the following correct. The first diagram below shows the torque and horsepower curves that Honda actually uses for the motor alone. I based it on an older paper published by Honda, for a slightly less powerful motor. It was easy to do:
  • Below about 4100 rpm:
    • It provides a maximum of 232.2 ft. lb. of torque.
    • The source of electricity is not defined, but to get that torque it must provide HP/1.34 kW of power.
    • This isn't a mechanical limit, it is a specifications limit. The source is controlled so that the motor does not produce more torque.
    • This is not the rotational rate used to drive the wheels; I suspect it is geared down by a ratio of 8.4, but I'm not sure.
  • Above about 4100 rpm:
    • It provides a maximum of 181 HP.
    • That means it provides torque equal to 951,000/RPM ft. lbs.
    • To get that power, the source must provide 135 kW of power.
    • And again, the source of electricity is controlled to achieve this limit.
What that poster refused to consider, was how the i-MMD works in Direct Drive Mode. That's the second diagram. What "212 horsepower @ 6200 rpm" means is that when the clutch is engaged, and:
  1. The engine is screaming at 6200 rpm.
  2. The car is pushing back with 121 ft. lb. of torque, so...
  3. ... the engine is producing its maximum of 143 HP.
Then the battery can provide enough electrical power to boost the horsepower, via parallel hybrid mode, to 212.

While it is a little more complicated with the i-MMD, the conditions for maximum horsepower are seldom, if ever, achieved by any car. In the case of the HAH, since it HAS NO TRANSMISSION, it would have to be going 167 mph to achieve 6200 rpm. A more traditional car might be able to get to the required speed, but not with the required torque.

That poster's main issues was how to achieve 212 HP. As I hope I have demonstrated, it's the wrong question. Nobody achieves the max HP of a car. They are found using a dynamometer. He used partial bits of the information I presented, and complained that he couldn't fill in the bits that are not only innapplicable, but impossible.

So why use HP rating? They can usually be scaled to more appropriate ranges. That is, doubling the max HP will approximately double the HP available in the ranges where you actually use the car. This is not true for the HAH. Because it almost always functions as an electric car, and does not use the device colloquially called "a transmission," it has more power at low speeds than its "max HP" value suggests. At high speeds, it has a little less.

That is why, when compared to the almost-identically rated 208 HP Toyota Camry Hybrid, it has significantly better acceleration from 0 to 50 mph, but loses some above 60 mph. And that is why it is important to know that the HAH does not have a transmission.

Edit: I added the T/HP curve for my previous 1999 Accord Coupe, for comparison to a gas engine. Note how the motor is far superior at low speeds, but the engine is better at high.
 

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I am not a hybrid owner, but read a lot. Honda hybrids have no transmission, CVT or otherwise. In most cases, the gasoline engine generates electric power to run the electric motor. The electric motor drives the car. During certain driving situations, highway cruising mostly, the gasoline motor is geared directly into the driveline, assisting the electric drive, where it is most efficient. The system tends to sound like a CVT, because of the way the gas engine speed rises to generate more electricity to raise the car speed. This system is only used by Honda among the hybrid systems out there. The function is similar to a diesel-electric locomotive. I believe it is the best way to go. Even the media took a while to catch on to this one.
You might want to read a little more because it does, in fact, have a CVT.
 

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You might want to read a little more because it does, in fact, have a CVT.
Sorry your both wrong. First, it has what Honda calls an e-CVT which is not the same thing as a normal CVT transmission. Second it does, by definition, have a transmission, just not a conventional one. A transmission is something that transfers power to the wheels.
 

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You might want to read a little more because it does, in fact, have a CVT.
... it has what Honda calls an e-CVT which is not the same thing as a normal CVT transmission. Second it does, by definition, have a transmission, just not a conventional one. A transmission is something that transfers power to the wheels.
It has a "transmission system," which means a system that transmits power from one point to another. What is usually meant by the abbreviated term "transmission" is a mechanical device that changes the gear ratio between the ICE and the wheels.

Of course the HAH has a transmission system; depending on how you count them, two or three different ones. Here's a schematic, from Honda documents:
518629

What it doesn't have, is a mechanical device that changes the gear ratio between the ICE and the wheels. What educated people (as opposed to those who try to shoe-horn what exists into their incomplete knowledge) say this is, is an "electric coupled CVT." That is, the set of all components in this diagram:
518631


Sad to say, "electric coupled CVT" gets translated into "e-CVT" in the media. A term used by Toyota to describe a mechanical device that is nothing like what is in the HAH.
 
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