Warning lights - Vital information or spurious distraction?

[john.wigley]

Originally Posted by owyn

Give me a warning light any day!
The next step, and its been going on in my industry for around 10 years, is what I'd call parametric analysis, the modern term is AI or machine learning. sensors are compared against a known normal.

It tells you something is going wrong before anything hits an alarm limit.

I would prefer far more info coming out of my car but an alarm management philosophy something like the IEC standard for process control, it doesn't have to be very complex in something simple like a car.

Firstly, thanks to everyone for your replies - it is the contributors that make this forum one of the best on the 'net in my opinion.

I'll concede that you have a point, 'owyn', which chimes to a certain extent with what 'CTA' said about things about to go wrong which you may not necessarily be aware of. I'd be more ready to agree if I could be confident regarding the accuracy and reliability of the sensors of which you speak.

Unfortunately - and we have seen the tragic outcome on two occasions recently in the aviation industry - sensors and related AI are neither reliable enough nor confidence inspiring. I would much rather remain in charge of my car - and accept responsibility for it's destiny - than for it be controlled by a computer.

Regards, John.

[Ian21401]

My old 940 only has a limited number of sensors It also has an OBD box so I don’t need a code reader. I don’t get warning messages on a screen display. If something unusual happens or something doesn’t feel right I interrogate that box. Sometimes I find an answer and sometimes I don’t. In my opinion, sensors and ECUs etc. should not be relied upon unless there is a back up, and a back up for the back up, especially when lives may be put in danger. Is it a faulty sensor, is it a poor connection, is it a faulty wire, is the ECU listening, is the ECU talking to another sensor? The possibilities seem endless.
My brother’s Focus died for no apparent reason and he eventually traced a broken earth wire in the main wiring harness where at manufacture a wire which was a few mms too short between an ECU and a sensor had been stretched over the edge of the bellhousing causing it to eventually break. It was only because of his wide electronic knowledge and fault finding expertise that he was able to find the fault. I certainly could not have done.
A fault on my son’s old Astra was never traced and the car was eventually scrapped.

[green van man]

Originally Posted by owyn

Give me a warning light any day!
The next step, and its been going on in my industry for around 10 years, is what I'd call parametric analysis, the modern term is AI or machine learning. sensors are compared against a known normal.

It tells you something is going wrong before anything hits an alarm limit.

I would prefer far more info coming out of my car but an alarm management philosophy something like the IEC standard for process control, it doesn't have to be very complex in something simple like a car.

I would far sooner have a gauge or two. Water temperature oil temp/preasure, ammeter, voltmeter, boost guage.
With these I can determine the health of my engine on the move.. warning lights rely on others parameters.

Years ago I had a Ford crossflow engined cortina, serviced it and used morris classic motor oil. 3 weeks running locally no problem, went on holiday 3/4 of an hour at motorway speeds saw the oil preasure drop from 60 psi to 40. The same thing happened on the return journey, motorway speeds saw oil preasure drop.
Got home and dumped the oil, last time I ever used morris oils and a good job I was running a high preasure oil pump , had I been running standard a 20 psi drop would of seen me running at half the recommended oil pressure for the engine for hours unaware as the oil light had a 7psi setting on the switch, a reason we fitted 25 psi switches and a bloody big indicator light on the rally cars.

Paul.

[owyn]

Originally Posted by green van man

I would far sooner have a gauge or two. Water temperature oil temp/preasure, ammeter, voltmeter, boost guage.
With these I can determine the health of my engine on the move.. warning lights rely on others parameters.

Years ago I had a Ford crossflow engined cortina, serviced it and used morris classic motor oil. 3 weeks running locally no problem, went on holiday 3/4 of an hour at motorway speeds saw the oil preasure drop from 60 psi to 40. The same thing happened on the return journey, motorway speeds saw oil preasure drop.
Got home and dumped the oil, last time I ever used morris oils and a good job I was running a high preasure oil pump , had I been running standard a 20 psi drop would of seen me running at half the recommended oil pressure for the engine for hours unaware as the oil light had a 7psi setting on the switch, a reason we fitted 25 psi switches and a bloody big indicator light on the rally cars.

Paul.

Its interesting that the perception is that sensors of whatever flavour aren't as reliable, the 737 max been an example.
The reality is that a sensor can pretty much do whatever you want and be as reliable as you want it to be. Although the Boeing issue isn't yet solved it looks like the process logic was gravely programmed such that it didn't fail safe. The antithesis to that problem was the Air France A340 which handed control back to the pilots when it lost a signal, the pilot then trusted the seat of his pants and flew the plane directly into the sea.
Planes aren't my specialist subject but turbines are and we are going through all our safety critical systems replacing mechanical systems with electronic, they are far more reliable, they just don't fail and even if they did the logic is set up that they fail safe.
A car is slightly different, the sensors can fail without any major problems, a minor irritance that a light has come on and it needs looking at. A SIL3 or 4 rated sensor that just wouldn't fail would probably cost 100 times more for very little benefit in the greater scheme of things.

The upside is that our cars are way more fuel efficient, have lower emissions and better power than ever before.


Don't get me wrong, I'm not a C&I guy, my degree is in straight mechanical engineering but I, probably like a lot of you view a pressure gauge going wrong because of water in the line or similar differently to a piezo sensor going bad. The fact of the matter is they both stopped working, its just that one is easier to comprehend for my mechanical brain than the other.

[DaveNP]

As I see it, the difference between an old fashioned mechanical gauge and an electronic sensor is the gauge will show a wrong reading which we can investigate as appropriate and also we can detect a trend on an analogue instrument rather than a sudden pass/fail alarm; the electronic sensor will more likely have an intermittent problem, usually wiring related, and ping and ping and ping at random intervals causing unwarranted distraction and frustration. Electronics and computerisation are good but the vibrating, hot, cold, wet, oily environment of a vehicle isn't good for the electronics, add that the manufacturers will inevitably work down to a budget, accepting a level of failure, rather than up to a level of reliability, and the perception of sensors being useless soon gains credibility.