[VIDEO] PORSCHE TAYCAN NO POWER AFTER KICKDOWN + ELECTRICAL SYSTEM FAULT | POWER ELECTRONICS INVERTER REPAIR

[ct14garage]

@F1Ruaraidh

Off-topic to this, but since you are in F1 I'm extremely curious..... and I can't help but ask

It is said that during the start procedure fuel is burned to spin the MGU-K and recharge the battery pack. This extra fuel burn produces more exhaust flow which in turn spools up the turbo. If you reach the top of the pack the MGU-K won't spin anymore and then you are just basically idling with reduced exhaust flow which doesn't spool the turbo (as much)..... This is what is said to have happened to George Russell in the last Hungarian Grand Prix....


Can this problem not be solved with an anti lag map in the ECU? Kinda like what we do here in random garages and tuning shops? Basically override DFCO retard ignition timing heavily into negative numbers, increase fuel enrichment and then let the fuel ignite in the hot exhaust manifold which spins the turbo?


Is this forbidden by the regulations this kind of ECU map?

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[F1Ruaraidh]

@F1Ruaraidh

Off-topic to this, but since you are in F1 I'm extremely curious..... and I can't help but ask

It is said that during the start procedure fuel is burned to spin the MGU-K and recharge the battery pack. This extra fuel burn produces more exhaust flow which in turn spools up the turbo. If you reach the top of the pack the MGU-K won't spin anymore and then you are just basically idling with reduced exhaust flow which doesn't spool the turbo (as much)..... This is what is said to have happened to George Russell in the last Hungarian Grand Prix....


Can this problem not be solved with an anti lag map in the ECU? Kinda like what we do here in random garages and tuning shops? Basically override DFCO retard ignition timing heavily into negative numbers, increase fuel enrichment and then let the fuel ignite in the hot exhaust manifold which spins the turbo?


Is this forbidden by the regulations this kind of ECU map?

Don't get me started on these feck stupid rules and changing them mid-season. I wrote the original report and recommendations for this ruleset with a colleague back in 2018 and then watched them get gutted and distorted by both the FIA AND the teams over the interceding years.

It's a mess.

Yes there are dozen things that could be done to reduce launch lag up to and including MGUK boost from the line (rather than at a miniumum speed) as well as full on anti-lag but, again, not permitted in the ruleset.

Winding the engine and turbo up against the K is also forbidden which is why they have to spend so long at retarded spark to wind up the turbo (which also negated Ferrari's decision to fit a smaller turbo to help with this and other issues). Truly unfair but it is what it is.

No George's problem was that the ECU was not in pre-launch mode so the spark timing didn't retard so when he went to launch throttle position he got far too many revs so had to back out. So then he was at low throttle to get the right engine speed and that meant he didn't have enough boost so straight to anti-stall.

All in the setup as he'd had an engine change so someone didn't reconfigure things correctly. It's all a time pressure thing and these setup changes can be easily missed. Particularly as MB use M files for everything rather than project files in System Monitor as intended..... Someone's getting a CAT 2 fault to solve after shutdown....

 

[ct14garage]

No George's problem was that the ECU was not in pre-launch mode so the spark timing didn't retard so when he went to launch throttle position he got far too many revs so had to back out. So then he was at low throttle to get the right engine speed and that meant he didn't have enough boost so straight to anti-stall.

All in the setup as he'd had an engine change so someone didn't reconfigure things correctly. It's all a time pressure thing and these setup changes can be easily missed. Particularly as MB use M files for everything rather than project files in System Monitor as intended..... Someone's getting a CAT 2 fault to solve after shutdown....

Thank you, I did see in the telemetry that Kimi was sitting at about 12,300 rpm with 30% throttle whereas George was also sitting at about 12,300 rpm but only 10% throttle. Makes sense. I thought it was battery related haha.... Thank you very much for that... my curiosity is now satisfied

 

[F1Ruaraidh]

Thank you, I did see in the telemetry that Kimi was sitting at about 12,300 rpm with 30% throttle whereas George was also sitting at about 12,300 rpm but only 10% throttle. Makes sense. I thought it was battery related haha.... Thank you very much for that... my curiosity is now satisfied

No worries my friend, happy to help!

Insider knowledge, we used to run bus caps to the thermal limit back in 2009, we literally had them all fitted with thermocouples externally and had a core temp model running real time too, that way you could push everything to the max without killing them. Bus cap cooling was key to inverter life and max performance. We discovered that one back in 2008, refined in 2009, developed further in 2010 (when there was no KERS raced) and refined again in 2011 when I was last trackside. 2014 ERS with H and K inverters in one box refined this even further when you effectively had a double inverter in one package....

Then you get to FE and all kinds of fun and games!!

 

[ct14garage]

Insider knowledge, we used to run bus caps to the thermal limit back in 2009, we literally had them all fitted with thermocouples externally and had a core temp model running real time too, that way you could push everything to the max without killing them. Bus cap cooling was key to inverter life and max performance. We discovered that one back in 2008, refined in 2009, developed further in 2010 (when there was no KERS raced) and refined again in 2011 when I was last trackside. 2014 ERS with H and K inverters in one box refined this even further when you effectively had a double inverter in one package....

Then you get to FE and all kinds of fun and games!!

Now I am very curious, no revisions were made to the Taycan cooling system within 9J1.1 (early 2019 had a slight revision). But other than that it all stayed the same.

However from my experience 2019 2020 and 2021 Taycan inverters fail A LOT (and it's always the bus cap) however the cooling remains the same.

Regarding the supplier of the bus caps I have no idea who supplies the factory ones. But I have my own supplier in China which supplies me with

70uF 1200V PE 300A inverter ×6 =420uF
600A inverter ×12 =840uF


However the results have been mixed, some have lasted over a year now. Others have come back quite quickly!

So we only offer this solution to customers who want to save money and cant afford the brand new replacement telling them very clearly that we are not 100% confident

 

[F1Ruaraidh]

If they are individual caps, I'd recommend measuring them all when you remove them from the HV PCB and noting their location on the PCB as you remove them. It's possible that the design of the PCB is preferentially ageing the ones "nearest" the bus electrically as they get worked harder.

Always preferred large size single prismatic wound electrolytics rather than multiple smaller caps for exactly this reason. We used to get them custom made.

I'm assuming they're all film caps rather than the ceramics we used to used on later more compact racing inverters? They were very very spendy and you ended up with 50 or so tiny caps but they were amazing. Balancing the load across the cap field becomes harder (and more important) when you have so many.

Do you know who supplies the Taycan inverter assembly?

 

[ct14garage]

If they are individual caps, I'd recommend measuring them all when you remove them from the HV PCB and noting their location on the PCB as you remove them. It's possible that the design of the PCB is preferentially ageing the ones "nearest" the bus electrically as they get worked harder.

Yes they are individual, and they always measure different capacitances among themselves. I always replace all of them so their capacitance is balanced when doing inverter repair.

I'm assuming they're all film caps rather than the ceramics we used to used on later more compact racing inverters? They were very very spendy and you ended up with 50 or so tiny caps but they were amazing. Balancing the load across the cap field becomes harder (and more important) when you have so many.

Film caps indeed

Do you know who supplies the Taycan inverter assembly?

The Japanese.... HITACHI

 

[F1Ruaraidh]

Well I suppose at least that's better than a bankrupt *Italian* company doing the 22kW OBDCs!!!

 

[F1Ruaraidh]

Yes they are individual, and they always measure different capacitances among themselves. I always replace all of them so their capacitance is balanced when doing inverter repair.

That does imply that differential ageing is occurring across the DC cap bank. Could be heat, could be differing electrical loading depending on location on the board. Worth tracking to get more data.

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