Alfa Romeo ECUs and computers

A long time ago, in a galaxy far, far away there were car making companies owned by governments and they made cars that they gave away without making any money at all. These cars were very environmentally friendly as they were water soluble and all was good in the world. Then one day these governments decided that they could no longer afford to to spend all this money on subsidising these companies and they sold them off . The new owners also found that these companies were like an albatross around their necks and try as they might the companies sucked the life blood from their hosts, eventually one of them went down, hopefully never to resurface (MG, Leyland or whatever they were called). Meanwhile the other struggles on, always with a bright future just around the corner. Then came a man with a plan and what this man saw was a revelation, he looked at the books of the company he was running and he wondered why in one of his factories (in Poland) each worker could make 100 cars while in the other (in Italy) they could only make 30, how could this be and what could be done about it and the answer was NOTHING he was hamstrung by the unions in his own country.

Meanwhile the government that allowed its car industry to collapse which effectively broke the unions power now makes double the number of cars that its rival does. The man with the plan for this small but extremely well liked company all of a sudden had his eyes taken of the ball by events in a distant land where banks sold off fools gold for the price of the real deal and there among the ashes he saw a gem of a company (Chrysler) which he bought for a song (almost literally) and now he has breathed fresh life into it, so much so that it now supports the empire he is rebuilding. Meanwhile back at the ranch the little company we all love seems to have been left in a little back water with no one at head office loving it, it only has a two model range and future models seem to be put back a year or so every time I see a new press release, so Mr Marchionne please spread some of your magic our way soon, we need it.

Back in the old days there were some real highlights though, like only having to work three days a week, being able to buy the Alfa Sud new. Flares, where did they go? weren’t they cool? Free love, Mmmm, cars that weighed under a ton; times were good, or were they? No electricity on your days off, servicing every 3000 miles. Points, who remembers them. Being able to gas yourself in the garage. All good things of the past.

Nowadays what have we got; nothing. You never come to see me...with your 21,000 mile service intervals, how can you build up a relationship with a customer when you only see them every two years? You get in your car and it will start and idle perfectly from cold, no messing about with chokes, you don’t think about starting it and allowing it to warm up a bit before you drive off, its key in, turn, drive, no problem. I fairly often read about the built in obsolescence of cars nowadays, even in these hallowed pages and I do think “thank good cars have moved on”, I like getting into my cocooned environment and being transported from A-B in comfort, don’t get me wrong I love my Bertone coupe and when the sun is shining it is the best car in the world but on a wet winters morning when all I want to do is get to work it just doesn’t cut the mustard.

So what has made that possible, the simple answer is computers, the computing power in a modern car is huge, the same is true of every part of the manufacturing operation from the beginning of the cars design process to the delivery of spare parts when the car is 10 years old all is controlled by computers.

Now we are all to some extent or another scared by computers mainly because we don’t know how they work. In some ways computers are quite simple in that they are effectively millions of tiny on off switches arranged in certain patterns, so a switch has two positions, on and off and each of these has a value. For example off is equal to 0 and on is equal to 1, using these two states for every time we put power through a switch we either get power out or we don’t from this we can make a simple language or binary language, I can feel you starting to switch off now but think about it we all know about language that doesn’t use the 26 letters we are used to, it is Morse code, now Morse code isn’t a binary language as there are in fact 5 different “letters”

1. Dot

2. Dash

3. inter-element gap between the dots and dashes within a character — one dot duration or one unit long

4. short gap (between letters) — three units long

5. medium gap (between words)

-- --- ·-· ··· · -·-· --- -·· · says:-

M O R S E C O D E

But in computer language (binary) morse code would be spelt;-

01101101 01101111 01110010 01110011 01100101 00100000 01100011 01101111 01100100 01100101

interesting isn’t it? So every time you need a computation you need to switch the computer on and off once, this is known as the clock speed of the computer for example when the Intel Pentium 4 chip was introduced it was the first Computer Processing Unit (CPU) with a clock rate of three billion cycles per second corresponding to ~3.0X10−10seconds per cycle or 3 GHz now that is very fast! So it can produce three billion 0’s or 1’s in a second.

Now by combining switches in different ways we can get them to perform logic. So by putting two switches in line we can make a simple logic gate called an AND gate and believe it or not computers do actually use these, So with an “and” gate in order to get power out of the wire at the end we have to close switch number one AND switch number two, it can be that simple. Then there are “or” gates so the two switches are side by side and by closing switch one OR switch two you get electricity out of the wire at the end. There are various other types of logic gate like this called things like and, or, not or nor which can be combined with each other in various ways to make the computer do all of its amazing feats.

 

The diagram above is a wiring for a microprocessor and the second row of symbols down there is a whole row of our AND gates.

Once all these switches have been made into AND, OR, NOT NOR logic gates and they have been assembled together onto a micro processor you have the basis of a computer. Now you have to make all these switches work and that is the job of the operating system like Windows or Linux. Now I really have no idea about programming one of these operating systems however I do know that my web site is programmed using a language called Personal Home Page or PHP that produces HyperText Markup Language (HTML) for your browser (google/firefox etc) to interpret.

Now this bit of code is for the banner at the top of our web site:-

<div id="awlogo"><a href="/"><img src="/Final image/Alfa Workshop Logo.gif" alt="Alfa Workshop Logo" width="350" height="80" border="0" /></a></div>

<div id="arlogo"><a href="/alfa_romeo_badge.shtml"><img src="/Final image/Alfa Logo.gif" alt="History of the Alfa Romeo Logo" width="181" height="80" border="0" /></a></div>


Now on a car most of the computers don’t have to give us information graphically, they have to do things like open a fuel injector for a certain precise time or monitor the speed the wheels are going round and for that they often have to control quite large currents now the wires inside a microprocessor are far to small to carry much current as I am sure you know you need quite a big wire to carry 10, 15 or 20 amps, think of the size of the wire in a 20 amp fuse and you get some idea of the thickness you need to carry that amount of current. So in order to control systems around the car the microprocessors have to have their outputs amplified using transistors for smaller currents or use relays to avoid having the large currents going through the Electronic Control Unit (ECU) and these are spread liberally and seemingly randomly round your car. All of these systems work seemlesly together and very rarly cause any problems, however I regularly hear the comment that when these systems go down when the car is 20-30 years old then the car will be unable to be repaired, I dont belive that this will be the case, we will be able to modify aftermarket systems to do the job of the original equipment to get us out of trouble. So I dont intend to get rid of my GTA any time soon as I dont think that we will have to much trouble with obsolecence in the near future.


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