Would they not already have a 'fail safe' option in the software?stevesingo wrote: ↑Fri Nov 16, 2018 10:43 amI can see MHPE developing contingency mapping in the case of VLIM failure. In that they will develop a map which is dependant on VLIM position so in the case of failure the ECU will adjust fuel and ignition compensations to ensure safe running.
Given the reported interventions by Brixton and the pit-wall it would appear that they did not have a fail-safe, or if they did it wasn’t safe enough.Big Tea wrote: ↑Fri Nov 16, 2018 11:07 amWould they not already have a 'fail safe' option in the software?stevesingo wrote: ↑Fri Nov 16, 2018 10:43 amI can see MHPE developing contingency mapping in the case of VLIM failure. In that they will develop a map which is dependant on VLIM position so in the case of failure the ECU will adjust fuel and ignition compensations to ensure safe running.
Maybe not best performance, but capable of continuing the race.
I follow, but assumed there would have been a 'keep it in one piece' mode that switched in automatically if things went outside the bounds of healthy. Like a limp home mode on a road car.henry wrote: ↑Fri Nov 16, 2018 11:29 amGiven the reported interventions by Brixton and the pit-wall it would appear that they did not have a fail-safe, or if they did it wasn’t safe enough.Big Tea wrote: ↑Fri Nov 16, 2018 11:07 amWould they not already have a 'fail safe' option in the software?stevesingo wrote: ↑Fri Nov 16, 2018 10:43 amI can see MHPE developing contingency mapping in the case of VLIM failure. In that they will develop a map which is dependant on VLIM position so in the case of failure the ECU will adjust fuel and ignition compensations to ensure safe running.
Maybe not best performance, but capable of continuing the race.
I’m guessing that they run with fixed maps for boost, injection quantity and timing, and spark timing. These values are then tweaked by evaluation of actual operating conditions based on sensor readings, lambda, detonation, exhaust temp etc. My guess is that there are boundaries as to how much the tweaking system can change the mapping and in this case they couldn’t change them enough.
And what exhaust issues would cause high EGT ?saviour stivala wrote: ↑Sat Nov 17, 2018 5:02 pm“VLIM?”. On lap 28 Mercedes PU engineers both at pit garage and back at base in UK monitoring telemetry reported that a failure was imminent due to an exhaust issue that had led to high temperatures.
Right so high EGT causing the exhaust to fail. What is causing the high EGT?saviour stivala wrote: ↑Sat Nov 17, 2018 6:51 pm"Well our exhaust is just about to fail, and we're overshooting all temperature limits".
Not a thread, but here’s a basic video from YouTube:Webber2011 wrote: ↑Sat Nov 17, 2018 8:04 pmFor dumbos like me, could someone explain how the VLIM works, or point me to the proper thread please ?
I have a basic understanding, but always like to learn more.
Thanks
Who can tell what was causing Mercedes high (1000-980 degree) EGT except their engineers in front of their flowing telemetry?. And speaking of Mercedes regarding 1000-980 degree EGT as high, I remember a 2003 BMW 3.0L V10 running at 19250 RPM registering a EGT of 1750 degree and there was no way they could use their Inconel exhaust headers for a second race.Mudflap wrote: ↑Sat Nov 17, 2018 8:11 pmRight so high EGT causing the exhaust to fail. What is causing the high EGT?saviour stivala wrote: ↑Sat Nov 17, 2018 6:51 pm"Well our exhaust is just about to fail, and we're overshooting all temperature limits".
That's what was being discussed but again you can't be bothered to read previous posts.
There aren't many reasons for EGT to shoot up, one such reason has already been discussed.saviour stivala wrote: ↑Sat Nov 17, 2018 9:23 pmWho can tell what was causing Mercedes high (1000-980 degree) EGT except their engineers in front of their flowing telemetry?. And speaking of Mercedes regarding 1000-980 degree EGT as high, I remember a 2003 BMW 3.0L V10 running at 19250 RPM registering a EGT of 1750 degree and there was no way they could use their Inconel exhaust headers for a second race.Mudflap wrote: ↑Sat Nov 17, 2018 8:11 pmRight so high EGT causing the exhaust to fail. What is causing the high EGT?saviour stivala wrote: ↑Sat Nov 17, 2018 6:51 pm"Well our exhaust is just about to fail, and we're overshooting all temperature limits".
That's what was being discussed but again you can't be bothered to read previous posts.
Correct, I do not pretend to be.Mudflap wrote: ↑Sat Nov 17, 2018 9:41 pmThere aren't many reasons for EGT to shoot up, one such reason has already been discussed.saviour stivala wrote: ↑Sat Nov 17, 2018 9:23 pmWho can tell what was causing Mercedes high (1000-980 degree) EGT except their engineers in front of their flowing telemetry?. And speaking of Mercedes regarding 1000-980 degree EGT as high, I remember a 2003 BMW 3.0L V10 running at 19250 RPM registering a EGT of 1750 degree and there was no way they could use their Inconel exhaust headers for a second race.
Once again your post adds nothing to the conversation, the whole point is to discuss potential failure modes. There are a few good engineers on this forum that can construct a good hypothesis, unfortunately you are not one of them.