Snow Cover On Roof Provides Wind Protection?

[Dan Lanciani]

In article , [e-mail] (Doug Miller) writes: | In article , ddl@danlan.*com (Dan Lanciani) wrote: | >In article , [e-mail] (Doug | > Miller) writes: | >| In article , ddl@danlan.*com (Dan Lanciani) | > wrote: | >| | >| | >| >I'm sorry if this is a stupid question, but I really don't know: | >| >typically, does shifting an automatic transmission into neutral | >| >actually disengage a gear or does it merely cause the torque | >| >converter to stop transferring torque? | >| | >| Neither, actually. It disengages a clutch inside the transmission. | >

| >Interesting. Is disengaging that clutch used for anything else (except | >perhaps park)? | | A typical automatic transmission has several internal clutches that are | engaged, or disengaged, by hydraulic pressure. The gearing in an AT consists | of multiple sets of planetary gears, and the clutches lock or release various | parts of the various gearsets to control the gear ratios. The clutches are | disengaged in both neutral and park. In park, additionally, the transmission | output shaft is mechanically locked by a pin or bar which prevents it from | turning. | | > If that clutch on my vehicle were not fully disengaging | >would I likely observe any other symptoms | | I would expect harsh shifts and unpleasant noises.

There's nothing obvious like that. Of course, with the transfer case I have my hand on the shift to feel the grinding. I did ask the dealer service guy about this but he just stared at me blankly. I had them change the transfer case fluid to see if I was causing any major damage (either by following or by not following the directions) and there wasn't any metal. I should note that for years I happily shifted the transfer ratio while in park. It was only when I noticed a blurb in the manual that I tried neutral. (The manual said not to shift in park because "the transmission will damage." I'm not sure if they meant "will be damaged" or will damage something.)

| >or would the torque converter | >absorb the rotation in park and at idle in neutral with the transmission | >loaded (i.e., with the transfer case not in neutral)? | | Given that the torque converter can absorb the engine's rotation with the | transmission in gear and the vehicle stopped with the brakes applied... I'd | have to say yes. :-)

Yeah, that was my thought as well. The system is too fault tolerant. :) I think the vehicle is too old to have enough sensors for the computer(s) to realize that the torque converter is absorbing rotation when it really should not be. And for all I know maybe it is normal for it to absorb a little in this case...

Dan Lanciani ddl@danlan.*com

[clare]

It disengages the drive clutches of the planetary gear sets - effectively disconnecting the gears.

The planetarys are still spinning, with some friction dragging the output around. Much better to shift in park - or come to a full stop, THEN shift into neutral and shift the transfer case quickly

[clare]

Which disengages the gears. Even in most manual transmissions today the gears (except for reverse) are in constant mesh.

[clare]

There is more than one "clutch" involved - and in most transmisions also at leat one "band" or "brake". They are applied in different combinations for different gears. Your tranny uses planetary gear sets, and by holding different elements of the set, different ratios are produced. Locking the input to the output with a clutch gives direct drive.

If any of the clutches do not release fully the fluid will quickly overheat and stink. Even fully released, with no load on the output shaft it will turn when the engine is running in neutral because of viscous friction (oil between the plates of the clutches etc)

[clare]

Like my auto mechanics licence number, my Diploma number and school, and the registration number for the plane under construction????? Fat chance!!!

[clare]

A "computer" CAN include a microprocessor, but does not need to. Google KURTA for a very good example of a strictly mechanical "computer" The earliest electronic computers also did not use a microprocessor, or even a central processing unit (CPU).

A Microprocessor is a COMPUTER COMPONENT that can be used for many processes, from the very simple to the very complex - only some of which are "computational" or numeric in nature.

From the Columbia Encyclopedia "computer: device capable of performing a series of arithmetic or logical operations. A computer is distinguished from a calculating machine, such as an electronic calculator, by being able to store a computer program (so that it can repeat its operations and make logical decisions), by the number and complexity of the operations it can perform, and by its ability to process, store, and retrieve data without human intervention. Computers developed along two separate engineering paths, producing two distinct types of computer-analog and digital. An analog computer operates on continuously varying data; a digital computer performs operations on discrete data."

If a microprocessor performs only a single operation (such as display data on a LCD screen, or decode a signal sent across a power wire to turn on a light remotely) it is not a computer.

If it reads several inputs and "computes" a result, and then creates an output that does something, it is a computer, like a cruise control computer, a transmission control computer, an ABS computer, etc. A computer can multi-task, running numerous processes at the same time, operating, for instance, engine fuel injection, ignition timing and emission control, as well as controlling the transmission and brake antilock systems - and by linking the three together also provide traction control and active stability control - all on one "computer"

Didn't know that. eh??

[clare]

Actually, a trip computer IS a computer, but unlike the '78 Caddy, the trip computer on MOST cars today is not a separate, discrete unit. The trip computer is a FUNCTION of either the PCU or the BCU (powertrain contol or body control unit) however it is referred to by any particular manufacturer. I was referring to calling a "display driver" a computer, even though it may have a microprocessor and rom in it to generate the characters.

SOME cars DO use a separate "computer" in the dash for the trip computer - and for things like "on-star" etc. But the number of computers has actually DECREASED in recent years as more and more functions are handled by fewer and fewer actual devices.

[clare]

At speed, shifting to LOW will not cause the transmission to downshift on most current automatics untill the speed drops low enough that the engine would not be over-reved to drive it in LOW, and the throttle is depressed far enough to accellerate the engine to the speed required to drive it at that speed in LOW. However, once it has shifted to LOW it will stay there when the pedal is released. The downshift enable speed may be slightly higher than the full throttle upshift speed, and higher than the full throttle kick-down (passing gear) speed. MOST will also NOT engage reverse above a programmed (and quite low) speed, to protect the drivetrain from damage. Shifting into NEUTRAL, WILL disconnect the drive. It MUST for safety reasons, and by the very design of the transmission. All current transmissions sold for highway use in North America have a "manual valve" that puts the transmission into a controllable condition so that the solenoids can apply or release the required clutches to drive the vehicle. When the Manual valve is put in neutral, no pressurized fluid is applied to the solenoids, so even if they are applied, the transmission will not transmit power to the output/wheels.. The hydraulic pressure is manually disconnected in both neutral and park positions.

Some hydraulic transmissions on off-road equipment are strictly electrically controlled (or at least were a few years ago) but loss of electrical power dissables the drive completely.

[krw]

That is *NOT* what I asked. Try reading for comprehension.

Are you really this stupid, or are you just pulling my leg?

I guess you really are stupid.

That's nice, but totally irrelevant.

Wrong.

A cruise control performs a single operation; accelerate/not so much.

I know you're an idiot, pretending to know something.

[Dan Lanciani]

| >Let me explain why I ask. I have a 1997 Toyota Landcruiser with | >automatic transmission. It also has a (totally mechanical) shift | >on the transfer case to select low or (normal) high speed. The | >manual says to put the automatic transmission in neutral when you | >want to change the transfer ratio. If I follow those instructions | >I hear/feel a nasty gear grinding when I try to shift the transfer | >case, suggesting that somehow the output of the transmission is | >still rotating with at least some force. | | The planetarys are still spinning, with some friction dragging the | output around. Much better to shift in park - or come to a full stop, | THEN shift into neutral and shift the transfer case quickly

Shifting in park works fine, but I'm not sure why they claim it will cause the "transmission to damage." But being at a full stop doesn't help. The specific sequence:

Vehicle parked in garage. Start vehicle in park. Shift to neutral. Shift transfer case from high to neutral; feel moderate resistance and tolerable levels of grinding. Attempt to shift transfer case from neutral to low; feel strong resistance and enough grinding to abandon attempt.

I've never tried to shift the transfer case with the vehicle in motion.

Dan Lanciani ddl@danlan.*com

[Doug Miller]

No, it doesn't. The teeth of the gears are still in mesh.

[trader4]

Neither krw nor I ever said that a computer needs to include a microprocessor. The reverse is what krw claimed, which is to say that a system that includes a microprocessor is a computer. Unless perhaps the microprocessor is being used as a doorstop. For the microprocessor to be of any use, it needs to be executing a program and capable of some kind of input/output. At that point it is a computer. It could be a very simple program only taking in some serial data, figuring out what the data is telling it to do, then activating the appropriate output. But that is just a simpler version of what your PC is doing.

I'd also point out that today, virtually all current computers do contain a microprocessor or microcontroller. Certainly evey one in today's cars do. So, why the trip down memory lane? For the record, I did google KURTA and KURTA mechanical computer and came up with zippo.

As I said above, if a system has a microprocessor it's a computer. It could be a simple one, that takes a few inputs and works a few switches, but it is a computer. That microprocessor is executing a program. Other than that the program is very simple, how is that any different than a microprocessor operating in a PC? And you never answered this question:

How about I write a simple assembly language program that implements a switch function, turning a keyboard light on and off, put it in a flash memory chip, and replace the bios on my PC with it? The light is now flashing. Is my PC no longer a computer just because it's running a very simple program?

Here's Collins dictionary definition of the word computer:

computer [k=C9=99m=CB=88pju=CB=90t=C9=99] n

1. (Electronics & Computer Science / Computer Science) a. a device, usually electronic, that processes data according to a set of instructions. The digital computer stores data in discrete units and performs arithmetical and logical operations at very high speed. The analog computer has no memory and is slower than the digital computer but has a continuous rather than a discrete input. The hybrid computer combines some of the advantages of digital and analog computers. b. (as modifier) computer technology Related prefix cyber-
2. a person who computes or calculates Collins English Dictionary

And from Merriam-Webster:

Main Entry: com=C2=B7put=C2=B7er Pronunciation: \k=C9=99m-=CB=88py=C3=BC-t=C9=99r\ Function: noun Usage: often attributive Date: 1646 : one that computes; specifically : a programmable usually electronic device that can store, retrieve, and process

Tell us what part of those definitions an 8051 running the dashboard display in a car would not meet.

Let's look at the first sentence: "device capable of performing a series of arithmetic or logical operations." An 8051 microcontroller running the dashboard display meets that definition.

Now let's look at the next part:

Now we're really out of the definition part, but they are making a specific comparison of what would distinguish an electronic calculator from a computer. But let's take this list of requirements anyway:

able to store a computer program number and complexity of operations it can perform ability to process, store and retrieve data without human intervention

An 8051 microcontroller running a dashboard display meets all those requirement.

It's still a computer because it has a CPU, memory, I/O and is executing a program.

So we also have the dashboard display microprocessor, which is receiving digital data serially from the ECU as to the cars speed, from the tranny computer as to the shift lever position, from the climate control computer as to the inside and outside temps, from the GPS as to the compass heading. Then using that data it computes how to activate the various display segments, responds to pushbuttons on the dash to work the trip computer, etc. Tell us how that is not a computer. Of course it is and it's called the dashboard display computer which should be on your list. It's also funny that in the above statement, we suddenly have 3 new computers in a car, not including the ECU and body computer. Gee, you started off telling us that most cars have only two and some only one.

I've forgotten more than you can ever hope to know. If you want to compare credentials, I would be happy to do so, but I don't think you want to go there. And what does the above have to do with anything? Are you now claiming that to meet the definition of a computer it must be capable of multitasking? Even if you want to make that claim, a simple 8051 microcontroller is quite capable of multitasking. As an example, in a display controller an 8051 could be receiving data on the vehicle speed on it's serial port, working the display segments and updating the distance traveled. Just like the ECU "computer"

You also completely ignored the highly credible link I gave you that says

This is a website for engineers that do embedded computer design. And they clearly say that even an econobox car today has a few dozen embedded processors. Or how about all the other media reports that you frequently see that talk about how many computers are in a typical home today? They are in everything from your cable box, to your microwave oven, your alarm system, your digital thermostat, your dishwasher, etc. Do you agree they are computers? And if yes, then what makes them different than using a microprocessor in a dashboard display?

I can give you my answer. They are all computers because they have a CPU, execute a program, and I/O.

[trader4]

m

I'd love to see a reference that says all that stuff, including the air bags, are run by one computer on any car. You also seem to be making very broad generalizations as to how all cars are designed. A simple google search on "air bag computer" brings up lots of hits. There is discussion on where it is, how to repIace it, etc. Funny how they call it an airbag computer, not an airbag/radio/compass computer and there is no mention of it doing anything other than control the airbags. Here's one link with a picture of the airbag computer from a Nissan.

And I can think of some very good reasons why designers would want an airbag computer to be dedicated to that one specific task. Can you?

[clare]

Never said that, did I???

I said a trip computer was a computer, didn't I????

I also said many vehicles incorporate it in the PCM or body computer, which controls many other functions of the car as well. Not arguing with you there. However, a PIC or other device used STRICTLY to drive a display, decoding a string of data from another computer to light the dots on an LCD is NOT a computer, even if it contains a microprocessor and a memory table that defines the characters to be displayed.. You may want to consider it a computer. I call it an intelligent display. The article about embedded controllers counts that as a computer.

It's all semantics.

Some are, some are not - and the definition is pretty loose. They are devices containing a microprocessor. They are dedicated digital control systems. They are systems that contain and utilize computer components. Are they computers? They are if you say they are. It's all semantics

It's all semantics. Is a PLC a computer? A "computer" can replace a PLC - It can emulate a PLC. It can run as a virtual PLC. It can BE a PLC.

A PLC is a more or less dedicated device - it is programiable, it is a logical device. It makes decisions based on binary logic inputs and a "program"and it can be programmed to CONTROL many devices from those inputs It can be FIELD PROGRAMMED, so I'd call it a computer.

If you state that the average luxury car today can contain upwards of

100 microprocessors, I'll agree with you. It's all semantics.

[clare]

Sorry - my mistake - google CURTA - AKA Peppermill rallye computer.

[Don Klipstein]

In , [e-mail] wrote, in something about microprocessor products being computers:

What if the microprocessor is controlling a mere battery charger? With the only program available to it being the one in its associated ROM that was put there by the factory?

Yes, I would concede that it meets a definition of "digital stored program computer" which is the "usual type of computer". But to what extent should a battery charger with program being burned into the same IC package as the processor be considered a "computer" as opposed to being a fancy sort of battery charger IC?

How about if the microprocessor has included within its IC package ROM (especially one-time-programmable "true ROM") a program that makes it useful or at least advantageous only as part of a ballast circuit for a single type or a small number of closely related types of metal halide lamp or other arc lamp? To what extent would one want to claim that a metal halide lamp ballast or a fluorescent lamp ballast is a computer due to having a stored program and a microprocessor of digital nature and I/O?

Suppose I invent a microprocessor-based ballast for a specific type of HID lamp that is an invention by achieving faster warmup without "excessive" starting/warmup related wear than anything previously disclosed. Such invention may have the program implementing means to-be-disclosed-in-patent-application-should-I-try-to-patent-one to maximize or even improve-upon-previous-achievements some novel way of faster warmup, or at least faster warmup of an HID lamp type that previously patented/patent-applied-for are no good for. The patentable improvement could have the burned-into-ROM program being a patentably novel improved one, at least for a specific lamp type. The program may be patentably novel by using sensed data and/or a "lamp thermal model" in a "novel" way, disclosed in the patent application. This could even be by disclosing in a patent application how a modification of a "prior art" lamp ballast is an invention by disclosing how it is inventive by being made suitable for a different lamp in an inventive way.

But I have digressed... Getting back on track, to what extent would / should one consider a lamp ballast or a battery charger, especially if more-specialized, to be considered to be a computer if it has a stored program, RAM, a microprocessor and I/O?

If a digital microprocessor controlling throttle in an automobile has inputs both from any user controls and from any sensors other than user controls, especially if it controls in addition amount of fuel injection and/or ignition timing, then I would consider that microprocessor, its program storage means, its likely-existing "memory" elsewhere (likely RAM), and its inputs and outputs (short of the sensors delivering the inputs and the devices responding to the outputs) to be a "computer".

Any comments from here?

- Don Klipstein ( [e-mail])

[trader4]

It is in fact a computer, an embedded computer. The fact that it's program is contained in ROM is irrelevant. In fact, the vast majority of embedded computers like those in cars, cable boxes, or your microwave oven have their programs stored in some type of non volatile solid state memory, ie ROM, Flash, etc. Did you look at the website link I provided to the embedded computing site that is a technical website dedicated to this type of computers?

It doesn't matter a bit where the program is stored. All you're doing there is moving more stuff on chip because it's cost efficient, less components, less power, etc, to do so. Microcontrollers are microprocessors that typically have:

CPU ROM RAM Parallel I/O ports On board peripherals, eg timers, interrupt controller, A/D, D/A, UARTS, etc

That doesn't mean they are no longer computers, just that more functions that used to be done with seperate chips has been brought on board. If anything, it makes them more capable, not less so.

The ballast is NOT a computer. It does contain an embedded computer though because it has a microprocessor running a program. Suppose I take my PC and instead of booting an OS, I replace the BIOS with a ROM containing a similar simple program to your ballast example. Is that PC no longer a computer? No, it's no longer a functioning PC, but it's still a computer.

Again, it's not the device itself that's a computer. It contains an embedded one if it has the things on your list.

That computer is just another version of what is going on in the battery charger or ballast. Yes, it has more inputs, more outputs and it's program is more complex. Consider though what even a simple microcontroller that is in a car controlling let's say the mirror position has to do. It starts up and starts executing code. First thing it has to do is program it's onboard peripherals. So, it starts loading values into registers for the timers, the interrupt controller. It loads values to set the speed of things like the serial port. At some point, it may suspend operating and wait to be re-awakend by an interrrupt which is caused by the serial port beginning to receive an incoming command for it to move the mirror. Now it goes into a loop to read in the packet of info. It has to check the parity on the packet or other means of determining that it is valid and not corrupt. Then it must break apart the packet and figure out what to do, eg move RH mirror to position 7. I could go on, but the point is that none of that is trivial. It involves taking in data, analyzing it, acting on it. The fact that it can all be going on in a single microcontroller that cost $1 is a remarkable statement of how far technology has advanced. But it in no way diminishes the fact that it is a computer.

Also consider the total confusion that would result from your approach or that of CL. You're essentially saying that at some arbitrary point, you consider an embedded microprocessor to be a computer, but it depends on factors that no one here has clearly defined. I'm saying that I've been in the industry and there is no confusion. Any embedded application that has a CPU, executes a program, has I/O is a computer. In a car, each of these modules would likely have one: engine control unit, ABS control unit, airbag control unit, etc.

Now CL has made some remarkable claims here. Among them that the typical car has but only two computers and many cars now have only one. He's claiming that everything is being centralized. That is completely contrary to everything that I have read and know to be true. I'm still waiting for a single reference for this.

He also claimed that he knows for a fact that:

"Well, I happen to know that the engine and transmission controls are "one computer" . The climate control, air bags, radio, compass, etc are another "computer".

I don't know how any manufacturer divides up the workload among computers. But I would lay money on the above being false. I told CL that I can think of some very good reasons why you would not want the airbag function to be mixed with anything else, let alone the radio. I never heard back from him. I think you likely know what I'm getting at. I also know if you google airbag computer, you sure get lots of hits and it sounds like there are a lot of them that are seperate modules.

You don't have to believe me. I've given you a link to a very credible source on embedded computing that says that a modern BMW or MB could have 100 embedded computers and even a cheap car has a few dozen.

Here's another good source. It's a book titled "Designing Embedded Hardware" by John Catsoulis, who holds a Masters in Computer Engineering.

"Computer systems fall into two seperate categories. The first, and most obvious, is that of the desktop computer....The second type of computer is the embedded computer, a computer that is integrated into another system for the purposes of control and/or monitoring. In fact, (the average home) may have 30 or more, hidden inside TV's, VCRs, DVD players, remote controls, washing machines, air conditioners......"

[Harry K]

Sora OT. When I first signed in I saw someone had said they googled the Curta Rallye calculator with no hits. I tried one quick search and came up with a page of them. Here is one:

Harry K

[trader4]

For the record Harry, what I said was I googled "KURTA" which is exactly what krw had posted. Sometimes what you think you saw and what was really there are two different things. Which is why I'm reluctant to treat self-reported interpretations of things as establishing fact.

And also for the record, your link doesn't work:

"The page -

- does not exist. "

[Jim Elbrecht]

-snip-

Whose law is it that says when you go to make a point on Usenet- you'll get bitten in the ass by a similar problem?

Harry's link *does* work for me. Yours doesn't-- but I don't know where the

came from--- [did you search the site instead of the web?]

Jim