Engine over-revving when dropping out of hybrid battery use

Faults and Technical chat for the Hyundai Tucson
Deleted User 1326

Post by Deleted User 1326 »

PhilHornby wrote: Tue Mar 12, 2024 2:18 pm
In normal ECO mode driving, the fact that the software uses more revs than you would, just illustrates what you've been doing wrong all these years ;)
Nobody likes to have their driving style or ability criticised but I see examples all the time in car forums where drivers fail to make full use of the gifts that modern technology has bestowed on us.

Whether it is Autohold in conjunction with the EPB, incorrect driving practice in automatic cars, a refusal to believe that FCA is actually operational, or not trusting smart cruise control, there are lots of drivers on our roads who seem incapable or are unwilling to practise new skills allowing them to adapt to much of the equipment, gadgets and gizmos in our 21st century cars.

Moreover, many seem to be stuck in a sort of post WW2 mindset when it comes to maintenance and can’t get their head round the fact that our cars don’t require additional oil & filter changes over and above those specified in the maintenance schedule.

I’ve heard all the various justification for refusing to change their ways but still, many of the whinges I read about in forums has little to do with the manufacturer or the dealer and much to do with the fact that the complainants have never learned to drive a modern car properly.

ntaylo
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Post by ntaylo »

PhilHornby wrote: Tue Mar 12, 2024 2:18 pm
ntaylo wrote: Mon Mar 11, 2024 6:06 pm the ICE suddenly started to exhibit gross over-revving due to operating in a lower than normal gear
Gross over-revving is not possible in this vehicle - it has a computer-controlled automatic gearbox!
If you think you can do better than Hyundai's Automotive & Software Engineers, put the car in "Sport" and use the paddles. It still won't let you grossly over (or under) rev the engine though...

Before overtaking, I often put the car in "Sport" and pull the paddle for a downshift. If such a downshift would be inappropriate, it ignores me. During the overtake - despite being in 'manual' - the car will still upshift as and when peak power/the rev limiter is reached. If you try to come to a stop with the car in 6th, you'll see it shuffling down the box, as you decelerate.

In normal ECO mode driving, the fact that the software uses more revs than you would, just illustrates what you've been doing wrong all these years ;)
I take note of your patronising response. This was nothing to do with me thinking I can do better than Hyundai's engineers. Agreed - the "computer-controlled automatic gearbox" works really well most of the time and I am delighted with the vehicle and its performance. However, I know that on the two occasions I described, something went temporarily but seriously awry. The car was running in Smart cruise control on both occasions (though the high revs behaviour continued with the mode disabled). An engine speed sticking at 4,000rpm (55mph) or 4,500rpm (60mph) is not normal behaviour for the auto gearbox.
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PhilHornby
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Post by PhilHornby »

ntaylo wrote: Sun Mar 17, 2024 10:58 pm I take note of your patronising response.
Apologies if I caused upset - it was not my intention.

My point is though: This powertrain is (I assume), like nothing you have encountered before. What, when and why, it does what it does, is not under our control. Perhaps it was revving to charge one of the batteries, or power the heater, or it's part of its GPF regeneration strategy? Who knows? It's been noted before, that it does like to use 'high' revs when climbing hills.

It's worth saying, that there's nothing inherently "wrong" with the engine revving at 4000rpm for lengthy periods. On my motorcycle, I never let the revs drop below 4000rpm - because it's out of its power band.
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COYB
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Post by COYB »

I have had this happen randomly over the 2 years I've had my PHEV Tucson. The terrain seems to be a factor - long drives through gently undulating hills seems to bring it on. It doesn't happen on the motorway but after say 25 miles of quiet A road seems to be a factor. Once I've parked up and then continued the journey the 'fault' seems to disappear. It only happens when the ICE is driving the car. It's almost as if whatever sensor it is that tells the gearbox to change up isn't doing its job. Once it happened just after coming off the motorway onto an A road then after accelerating to about 50 the engine RPM seemed to peak. Quickly changing up on the paddles got it back to normal. The engine is quite noisy anyway under acceleration but this seems to be the same with all the 1.6 engines as I noticed when driving manual version of the car (it being a courtesy car).
I'll take it to the dealers but expect no joy. They had a test drive last time I reported a noisy engine when under load going up a hill but the car wouldn't demonstrate the fault.
COYB
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Post by COYB »

"Gross over-revving is not possible in this vehicle - it has a computer-controlled automatic gearbox!
If you think you can do better than Hyundai's Automotive & Software Engineers, put the car in "Sport" and use the paddles. It still won't let you grossly over (or under) rev the engine though...


PS: I'm not sure I have the same degree of faith as you Phil - no doubt there are some excellent engineers and programmers but the same could be said of Boeing engineers before the 737 Max airplane disasters. As an ex programmer myself I know how extremely complex it can be to test mission critical software. Errors do occur despite the best testing tools available - witness also the recent Crowdstrike induced outages on millions of computers. Let's keep an open mind.
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PhilHornby
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Post by PhilHornby »

It does seem to be location-aware and adopt this strategy mainly on hills. But I reckon it's because a gear-change is quite a 'high cost' operation on this powertrain (involving spinning the ICE to the correct rpm for the next gear - using the HSG - before dumping the clutch again).

Whatever the reason, no harm ever comes of it...

The Crowdstrike analogy is different. Maybe the day is not far away, before some car manufacturer delivers an ill-conceived OTA update and disables every vehicle they've ever sold :shock:

I recently asked the purveyor of my Central Heating Control System (Wiser/Drayton/Schneider call 'em what you will), how they would modify their update strategy, in light of the Crowdstrike lesson. In response, they deleted my post from their Support Forum :!:

(They broke the system a year or two back and I had to tell them what the bug was! I told them to cease-and-desist this activity, but they didn't, so my system has been firewalled from the Internet ever since...)
N Line S Hybrid (HEV).
23 plate - built Nov '22
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Indalo1
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Post by Indalo1 »

COYB wrote: Sat Aug 10, 2024 5:11 pm I'll take it to the dealers but expect no joy.
Please keep forum readers appraised of your visit to your dealership in case there is anything to be learned about the behaviour that seems to be a concern for some.
Hybrid in Ultimate trim - ordered 12/05/23 - Collected 07/06/23
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Osmosis789
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Post by Osmosis789 »

Hi, I have a very similar fault. Did you get to the bottom of this with your dealership?
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PhilHornby
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Post by PhilHornby »

Osmosis789 wrote: Mon Feb 03, 2025 1:33 pm Hi, I have a very similar fault.
It's not a fault, it's an algorithm :?
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Raiders66
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Post by Raiders66 »

I notice that when I come out of Hybrid the revs sit just over 1000-1200 and go a bit lower say 1000 when the engine warms up a bit. Thought it was just the way the system worked, but nothing like what others are facing.

Mark
2021 Ultimate Hybrid in Dark Knight Grey, with Moss Grey Leather interior.
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