With all the software glitches we seem to encounter with all our new vehicles, not just the Cayenne, why are there so many "modules" and computers on the cars. I tried to get the fog lights to work without the headlights on my S4 Audi or A4 company car with my VAG-COM program and it won't let me on the newer models. Could do it easily on my '02 A4. Of course, it was easy to wire on my older Porsches, etc. Now I'm afraid to rewire the fog lights on the Audi for fear of having some module go balastic! What the hell is the advantage of all these software glitch prone "modules" anyway??????????????

 

Definitely a valid complaint. If you quote rough examples of what's going on while you're driving, it seems rather impressive. Namely, a lot of the statistical data being measured and stored, traction control combining (depending on the car) other instantenous measurements, and so on. However...the car is pretty much a 'closed system'. Testing shouldn't be that hard and one would thing more important considering it's a vehicle and not some basic electronic gizmo.

I'm rather annoyed that a lot of these modules don't have better written firmware as well. Shouldn't be that hard. I pacify my frustration by telling myself that hiring top-notch programmers is not something car-makers are completely familiar with and is somewhat new. I wonder how many Software Engineer grads actually believe a career awaits them at Porsche/Mercedes/etc.

 

I just want to add to my previous comments in another thread:

https://rennlist.com/forums/showthre...97#post2469697

The reason there are so many computers in our cars is because of the increased complexity or our cars compared to yesteryear.

An example is the airbag control unit. It is a little box beneath the seat about the size of a deck of cards. It takes as input pressure readings from a diaphragm in each seat (to weigh the passenger), an vertical accelerometer to adjust the diaphragm readings for bumps in the road, and a lateral accelerometer to determine whether there is deceleration or sideways movement as in an accident. The computer software has algorithms to determine whether the load on the seat is inert (as in a box) or alive (as in a person). The software takes all this and more into account and must decide whether to fire an airbag in less than 1/10 of a second.

Another example is the sheer volume of electrical equipment in the modern automobile. It used to be that wiring went from the power source to a fuse box, to some switches, and then to each device. Now there are so many devices we have a computerized switching unit to reduce the amount of wiring. They are no longer connected by wire but by network cable. It is analogous to the rather straighforward wiring in your house, compared to the wiring in an office building that demands much more sophisticated distribution systems.

A final example is the engine control unit. There is no denying that a 4.5 liter engine of today produces much more horsepower than a small-block V-8 of the 60's. Furthermore we get about 35% better gas mileage and far less emissions for the horsepower the engine produces. We get this because of electronic ignition, fuel injection and variable valve timing, all controlled by computer. Sure I enjoy adjusting the valves on my 356 motor but I know my twin carbs don't not even approximate the efficiency of my Cayenne fuel injectors.

But let's not deny there are problems with the explosion of computers in our cars, especially when it comes to the software. Embedded software development is much more challenging than software for desktop computer systems. There are far fewer engineers that are even capable of doing this kind of programming. The processes required to produce reliable software are not well understood or adhered to by the majority of developers. In many cases engineering management, particularly in the automotive industry, does not understand the nature of software at all.

The increasing level of software complexity is introducing system errors into a consumer base that is very intolerant of any defects whatsoever. The competitive edge will go to autobile manufacturers and tier one suppliers who figure out how to develop reliable software.

 

Interesting post- you mean the Webers on my 914 aren't as fancy as the ECU on the GT3 or Cayenne

 

356driver-

Sounds like you have some more in-depth knowledge of Porsche's computer system. Quick question- is all that you mentioned concerning the Airbag system common to many auto manufacturers or is that unique to Porsche?

Anyway, like I said in my earlier post- if you rattle off the list of features and start to comprehend some of the complexity that reflects the state of autos today, it does sound and is actually impressive. However, like in your example of the airbag, that really isn't a hard thing to do. Given all the inputs you listed and perhaps some more we may not know about, we could rather easily come up with an algorithm to make that 1/10 second decision. In fact, with some pretty cheap microcontrollers (sub $5) we could make those decisions more in the micro to nano second range. As far as algorithm development, it is far from difficult. And firmware development on a whole is much easier than software development, of course it depends on the project. But simply by virtue of the fact that you're dealing with a closed system makes is a LOT easier. Having done a lot both, embedded systems were always easier just because of the nature of the beast.

My complaints with the firmware aren't too technical or geeky, I've just been unimpressed with the quality of what I've seen over the years. I suppose my biggest peeve is that many manufacturers offer some pretty basic features and relatively simple software features like average gas consumption, trip computers, etc. as additonal packages costing hundreds of dollars! Oh well, software developers have been gouging us for years for the same. If the only way to get cost down in the auto industry is something like open-source tools....forget it...I'll keep paying for the 'upgraded' in-house developed features. I pray we never see marketing like:

450 HP, Power Sunroof, Nav System and runs on Linux!!!