To me, anyway, the vcm's (vehicle control module) in my cars seem a wonder. How do they design such indestructible electronics? I'd like to see a sc hematic of a common automotive computer or something that describes the des ign techniques that they use. And is it just good design or is it the part s they use.
Thanks in advance.
They're not indestructible - far from it. I had one fail totally last summer and the replacement cost not far shy of a thousand dollars.
Around the Phoenix area the annual hilarity is watching new model GM cars with infant failures in the heat >:-} ...Jim Thompson
...but if my mechanic is telling me the truth, they are absolutely and unconditionally unrepairable.
JT is a retard.
He likely buys retarded Nazi Fords.
Mechanics don't do electricity IME. (I don't do car engines so I suppose that's fair).
I've only seen GM engine-control units up close... they are hybrids built of ~1/8" Alumina. They would be repairable in a hybrid facility, but not in any auto shop. ...Jim Thompson
Relative to the kinds of things automotive electronics are designed to handle:
- High temperature parts (175C?)
- Suitable derating for operating current at high ambient (especially for engine bay parts)
- Transient and load dump protection (often includes a pre-regulator sort of thing, to ride out the excess voltage)
- Output/switching with protected devices (current and thermal protected FETs, etc.)
There's also mission-critical MCUs (lock-step cores for example), which of course don't do much good without the hardening/support bits around them.
Tim
It was -10 degrees last week here in Boston, and while my enviro-weenie GM Volt didn't fail, the ECU certainly was complaining a lot about it.
"Warning: Propulsion power reduced" "Parking brake error" "Caution: Ice possible, drive with care" "Engine running due to temperature"
The car is a bit like my mom.
such things as transmission and flywheel sensors.
[snip] ...Jim Thompson-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at
It's been a wee bit on the cold side here in Arizona, too. Only going
(This is our energy-neutral time of the year... virtually no heating/cooling needed until around mid-May)) ...Jim Thompson
I beg to differ. There are plenty of small shops advertising ECU repair services: I've also bought or exchanged used ECU's on eBay with mixed results. You might want to show the list to your mechanic, or find a more clueful mechanic.
Repairing ceramic substrate hybrid type ECU's is a bit messy, but not impossible:
One of my friends has a car which requires that the battery be disconnected for a few seconds before the ECU will boot. It's fairly old and he doesn't want to spend the money on a replacement black box.
"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
Yeah, so you only get 35C overhead, but that's better than the 10C overhead you get for 150C parts (let alone commercial 85C parts that wouldn't work at all :) ).
Tim
Not unrepairable with the right tools (there's 'rebuilt' ones on the market), but there's a rubbery overcoat on mine, so you need to know how to strip that off (and maybe replace it later) before tinkering.
Mine is on an '83 Ford, more recent computers might be different.
On a sunny day (Sun, 21 Feb 2016 13:27:48 -0600) it happened "Tim Williams" wrote in :
And vibration proof. I had a car once that ran on LPG (liquid Petroleum Gas), the solenoids that controlled the gas tank were controlled by a relay on a board that was vertical soldered against an other board with a transistor relay driver, The board (solder joint) of course broke, just lucky the relays was off. Cars have blown up. I repaired it, the garage did not know what it was,. So much for certified garage repair shops here.
I'm talking about things like repairing a crimp on a wire. They "replace the wiring harness" :)
Like the medical "profession"... add more prescriptions that they get a kick-back from. ...Jim Thompson
Grin.. you've got a Volt?
My latest car... (2009 corolla) has got anti-lock brakes. When coming down "my" hill on snowy mornings I sometimes get the feeling that I would have more control with-out the anti-lock feature.. but it's hard to know without some way to switch it on and off.
It also beeps at me and flashes lights when I break loose the wheels going around a corner at "speed"..... or just climbing up "my" hill on a snowy evening. AFAICT it down't cut power to the wheels... but with all the beeping an flashing it's hard to tell.
George H.
Yeah, it's a great car - the dealer made me an offer on the outgoing
2015 model that I couldn't refuse. Even with gas prices as low as they are, a full charge overnight from a wall outlet is good for about 40 miles and costs well under a dollar. And I use a lot of public level 2 chargers that are free. My current lifetime combined fuel economy is about 75 mpg.It does well when running on the gas backup as well because it incorporates all the same hybrid technology as the Prius, though not quite as good because it's not designed as a strictly hybrid vehicle and is a physically larger car. Mid to high 30s on the highway is easily done.
The downside is it doesn't do so great at low temperature - the engine will come on for a few minutes to warm the battery coolant up to operating temperature when it's very cold. All coolant for both the engine, battery, and HV system is GM 50/50 "Dex Cool", a mixture of antifreeze and _deionized_ water.
The main electric motor is rated at 150 HP, there's a smaller auxiliary electric motor that also functions ans a generator, and the gas engine is an 85 HP 1.4L I4, I believe it's a naturally aspirated modified version of the one used in the current generation Chevy Cruise. The only downside is that it requires premium fuel - the manual suggests 90 octane but as only 89 and 93 are commonly available here I run 89 and it seems to do fine. Currently 89 isn't that much more expensive than 87, about $1.99 a gallon vs $1.75. And I try to only burn about two or three gallons of gas on a good week.
Apparently it needs the higher octane not because it has a significantly larger displacement than the stock Cruze engine, but because of the design of the engine-generator system it spends most of its life WOT. I believe the 2016 Volt redesign has a smaller engine, a 1.0 I3, which doesn't require premium fuel.
It's not a Tesla, but it's pretty quick off the line - 0 - 30 time on the battery is around two and a half seconds.
Why does so many feel the need to encrypt their posts? What does WOT mean? World of Tanks and Web of Trust are the two that show up on a google search. WTF
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