Hyundai Kona - Mild Hybrid Wierdness

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Fri 10 Nov 2023 23:38
Hyundai Kona - Mild Hybrid Wierdness - Ian_SW

I've been driving around this week in a Hyundai Kona "Mild Hybrid" hire car. I'd had a few other mild hybrids recently and all seemed to be just glorified "stop-start" but this one was a bit different.

The most odd part was that it had a manual gearbox, but the engine would completely shut off sometimes when you took your foot off the accelerator with the car in gear and the clutch engaged, even at motorway speeds. The only way I think that could be achieved mechanically is with a second automatic clutch in addition to the normal foot-operated one. This got me thinking, why did they bother doing this and not just fit an automatic gearbox instead?

Some of its "start stop" logic was rather illogical too - for example if the engine had gone off as described above, it seemed to always restart if you pressed either brake or clutch pedal. In reality when driving this as you would in a normal manual, this meant that the engine was idling at the vast majority of traffic lights instead of being off. The only way to get the engine to stay off at traffic lights seemed to be to knock the car into neutral while the engine was still running, re-engage the clutch and coast in neutral when applying the brakes. The engine then switched off when the car was doing about 10mph and remained off until the clutch was dropped.

All this didn't seem to have achieved much in terms of better fuel economy - the mid 40s MPG was very similar to what I've seen in similarly sized normal petrol cars.

Are other mild hybrids like this, or is this something specific to Hyundai?

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Sat 11 Nov 2023 06:38
Hyundai Kona - Mild Hybrid Wierdness - badbusdriver

The most odd part was that it had a manual gearbox, but the engine would completely shut off sometimes when you took your foot off the accelerator with the car in gear and the clutch engaged, even at motorway speeds.

This is what Hyundai refers to as "Sailing", a bit like the freewheel function in some old cars. But just to be clear, it only happens in Eco mode.

The only way I think that could be achieved mechanically is with a second automatic clutch in addition to the normal foot-operated one. This got me thinking, why did they bother doing this and not just fit an automatic gearbox instead?

Not sure I understand your logic?, why would having a second clutch make no sense as a manual?, Seems simple enough to me, some people don't want an auto (plus, an auto will add a chunk on to the price of the car)

Some of its "start stop" logic was rather illogical too - for example if the engine had gone off as described above, it seemed to always restart if you pressed either brake or clutch pedal. In reality when driving this as you would in a normal manual, this meant that the engine was idling at the vast majority of traffic lights instead of being off. The only way to get the engine to stay off at traffic lights seemed to be to knock the car into neutral while the engine was still running, re-engage the clutch and coast in neutral when applying the brakes. The engine then switched off when the car was doing about 10mph and remained off until the clutch was dropped.

If the driver is pressing the brake, the engine comes back on to give the option of engine braking and if the driver presses the clutch, the car will assume the driver wants to change gear. Seems logical to me(?), if you want the engine off as long as possible, keep your feet off the pedals.

Sailing is completely separate from the stop start though, that switches the engine off while stationary and with your foot on the brake pedal.

All this didn't seem to have achieved much in terms of better fuel economy - the mid 40s MPG was very similar to what I've seen in similarly sized normal petrol cars.

We have recently taken delivery of a Hyundai Bayon MHEV with the 120bhp 1.0 turbo and DCT auto. Early days yet, but a trip to Glasgow and (almost) back resulted in an average of 47mpg. Fairly strong headwind on the way, lighter tailwind on the way home and doing between 70 and 75mph. The thing I found annoying was that sailing doesn't happen when using cruise, so the mpg could have been higher. Stopped for fuel 15 miles from home and had 55mpg showing when we got home on the 60mph roads and not using cruise. I think it will take a bit of practise to maximise potential economy though.

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Sun 12 Nov 2023 10:23
Hyundai Kona - Mild Hybrid Wierdness - Andrew-T

<< We have recently taken delivery of a Hyundai Bayon MHEV with the 120bhp 1.0 turbo and DCT auto. Early days yet, but a trip to Glasgow and (almost) back resulted in an average of 47mpg. Fairly strong headwind on the way, lighter tailwind on the way home and doing between 70 and 75mph. >>

I'm still not clear what these figures of 45-55mpg actually represent. My 30-year-old 205 gets over 50mpg with its 1.4-litre petrol engine. So this Hyundai has done a lot of running just to stay in the same place, consumption-wise. If its EV battery is also being charged 'offline', that presumably uses additional fuel somewhere so the car's real consumption is worse than quoted ?

So much for the aim of reducing emissions ?

Edited by Andrew-T on 12/11/2023 at 10:24

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Sun 12 Nov 2023 15:54
Hyundai Kona - Mild Hybrid Wierdness - skidpan

<< We have recently taken delivery of a Hyundai Bayon MHEV with the 120bhp 1.0 turbo and DCT auto. Early days yet, but a trip to Glasgow and (almost) back resulted in an average of 47mpg. Fairly strong headwind on the way, lighter tailwind on the way home and doing between 70 and 75mph. >>

I'm still not clear what these figures of 45-55mpg actually represent. My 30-year-old 205 gets over 50mpg with its 1.4-litre petrol engine. So this Hyundai has done a lot of running just to stay in the same place, consumption-wise. If its EV battery is also being charged 'offline', that presumably uses additional fuel somewhere so the car's real consumption is worse than quoted ?

So much for the aim of reducing emissions ?

The Hyundai is a MHEV which has a tiny 48V battery. They only have a capability to drive very short distances on electric alone at low speeds. All the technology has been developed for is to lower the emissions in town. We drove a Golf with Mild Hybrid and it was actually pretty good. No quicker than a normal 1.5 TSi and probably no more economical but the slow pull off I have found with all VAG DSG's (except the PHEV we have) is pretty much sorted making the car a far better drive.

Suppose they have their place but if a proper hybrid is available in the range buy that, better still get a PHEV.

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Sat 11 Nov 2023 06:45
Hyundai Kona - Mild Hybrid Wierdness - Oli rag

I seem to remember reading about a freewheeling device that involved a dog clutch being fitted to recent Hyundai/ Kia’s.

I would think that all this technology ( extra clutches, mild hybrid motors and associated electronics) is there to reduce the emissions slightly.

Whether owners feel that all this extra tech fitted and the possibly higher mpg achieved by it, is offset by a possible reduction in reliability and long term repair costs, I don’t know?

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Sat 11 Nov 2023 09:30
Hyundai Kona - Mild Hybrid Wierdness - gordonbennet

Seems an awful lot off faff to me, especially for so little if any fuel gain from the OP's experience when comparing with other similar (simpler? if thats possible any more) vehicles.

Trucks with automated manuals have for some time engaged a clutch and allowed the vehicle to free wheel but the engine always remains on tickover during this, it doesn't always work because with the weights involved one can soon exceed the programmed in tacho allowances and trigger overspeeds on the system for as little as 58kph when 56 is the vehicles set limit, apart from that coasting was drummed into us now old school lorryists as taboo for many decades (as if we'd even consider using Irish/Aberdeen Overdrive :-) but now its all fine because it suits, confess when i use certain vehicles where eco cruise as its called on some makes can be switched off i do so preferring to keep the drive line engaged at all times.

Having had a few years of experience of it with trucks now i wouldn't want it on a car either.

It was fine on Rover P4s and two stroke Wartburgs of yore, in those cases it was simple and the engine stayed on tickover.

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Sat 11 Nov 2023 21:30
Hyundai Kona - Mild Hybrid Wierdness - misar

Seems an awful lot off faff to me, especially for so little if any fuel gain from the OP's experience when comparing with other similar (simpler? if thats possible any more) vehicles.

As already noted the main reason is meeting emissions regs and/or tax brackets not better economy. Having said that, going from a Gen 2 to a Gen 4 Mazda 3 (both with stop-start, both 2L petrol) I got a substantial improvement in mpg without any attempt to change my driving style.

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Sun 12 Nov 2023 00:50
Hyundai Kona - Mild Hybrid Wierdness - focussed

"It was fine on Rover P4s and two stroke Wartburgs of yore, in those cases it was simple and the engine stayed on tickover"

The reason for the freewheel clutch on the Wartburg and on the two-stroke Saab was to avoid the situation where on lifting off the throttle at high speed, the engine would be hot and turning at high rpm without ingesting much if any fuel mixture which also contained the lube oil.

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Sun 12 Nov 2023 18:44
Hyundai Kona - Mild Hybrid Wierdness - badbusdriver

<< We have recently taken delivery of a Hyundai Bayon MHEV with the 120bhp 1.0 turbo and DCT auto. Early days yet, but a trip to Glasgow and (almost) back resulted in an average of 47mpg. Fairly strong headwind on the way, lighter tailwind on the way home and doing between 70 and 75mph. >>

I'm still not clear what these figures of 45-55mpg actually represent. My 30-year-old 205 gets over 50mpg with its 1.4-litre petrol engine. So this Hyundai has done a lot of running just to stay in the same place, consumption-wise. If its EV battery is also being charged 'offline', that presumably uses additional fuel somewhere so the car's real consumption is worse than quoted ?

Apples and pears though isn't it?. The Bayon might be a small car in this day and age, but it has a "footprint" of around 27% more than a 205 (for some reference, the difference between a Polo and a Golf is less than 10%), and more importantly (in urban running), weighs around 50% more. Our recently departed Suzuki Ignis, mechanically at least, is no more advanced than your 205 but could exceed 60mpg on single carriageway A and B roads. At 70+mph though, I doubt it would be any more efficient than the Bayon because it simply isn't very aerodynamic. Not that the Bayon has a particularly slippery shape, just more than the Ignis. And at that speeds, aerodynamics is much more important (within reason) than weight when it comes to mpg.

As I said, the coasting won't work with cruise on, so if I'd been prioritising mpg, I wouldn't have been using it. Also probably worth pointing out that, for whatever reason, the engine doesn't cut out on our car, it just drops the revs to idle speed. Presumably something to do with it being the (DCT) auto?

Also, the battery in an MHEV is charged solely by brake regen, so it does not skew the mpg at all.

The Hyundai is a MHEV which has a tiny 48V battery. They only have a capability to drive very short distances on electric alone at low speeds.

Not sure about MHEV's made by VAG specifically, but to the best of my knowledge, an MHEV won't drive the car any distance.

All the technology has been developed for is to lower the emissions in town.

In most cases maybe, but the coasting on Hyundai's (and presumably Kia's) is enabled by the mild hybrid system, and that is clearly going to be of most benefit to the mpg and emissions at main road speeds.

Suppose they have their place but if a proper hybrid is available in the range buy that, better still get a PHEV.

That's fine and dandy if money is no object, but an HEV is going to cost appreciably more than an MHEV (of the same car) and a PHEV is going to cost appreciably more again.

Difficult to compare like for like because I don't know of any single model available as an MHEV, HEV and PHEV. But the Hyundai Kona is available as a MHEV and HEV, the cheapest version of the former (same trim but manual gearbox) is £4380 less than the latter.

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Mon 13 Nov 2023 19:38
Hyundai Kona - Mild Hybrid Wierdness - Ian_SW

The "Sailing" as I now know it is called felt like it was near useless when driving normally. It only engaged when I wasn't touching any pedal, which meant unless the hill was a very specific gradient the car would either speed up or slow down. Equally, once it had been "used" in the coasting to slow down on approach to traffic lights, the engine restarted as I touched the brakes. Then, with the car stopped, the engine didn't switch off again as it would with start-stop, presumably because it had only just started and was protecting itself.

It seemed to be most efficient, in terms of the engine being off when it wasn't needed if I ignored everything I've ever been told about how to drive and knocked it into neutral and lifted the clutch before even starting to slow down. The engine would then mostly switch off while the car was still moving and then stay off until I dropped the clutch to select a gear to set off.

I've had better economy in a Ford Kuga and Skoda Karoq - both bigger cars, and both only with "normal" start-stop, which makes the mild hybrid technology seem pretty pointless. Proper hybrids there is a benefit to - I had an Ioniq full hybrid the previous week which did 65mpg and I get similar in my car which has the Toyota hybrid system, much more than is possible in any similarly sized cars with petrol engines.

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Mon 13 Nov 2023 20:20
Hyundai Kona - Mild Hybrid Wierdness - RT

The "Sailing" as I now know it is called felt like it was near useless when driving normally. It only engaged when I wasn't touching any pedal, which meant unless the hill was a very specific gradient the car would either speed up or slow down. Equally, once it had been "used" in the coasting to slow down on approach to traffic lights, the engine restarted as I touched the brakes. Then, with the car stopped, the engine didn't switch off again as it would with start-stop, presumably because it had only just started and was protecting itself.

It seemed to be most efficient, in terms of the engine being off when it wasn't needed if I ignored everything I've ever been told about how to drive and knocked it into neutral and lifted the clutch before even starting to slow down. The engine would then mostly switch off while the car was still moving and then stay off until I dropped the clutch to select a gear to set off.

I've had better economy in a Ford Kuga and Skoda Karoq - both bigger cars, and both only with "normal" start-stop, which makes the mild hybrid technology seem pretty pointless. Proper hybrids there is a benefit to - I had an Ioniq full hybrid the previous week which did 65mpg and I get similar in my car which has the Toyota hybrid system, much more than is possible in any similarly sized cars with petrol engines.

My conventional diesel automatic has a "coasting" feature which selects neutral when you lift off the throttle and then re-engages as soon as the throttle is touched - I hated it but fortunately it can be turned off on one of the menus - it didn't seem to help fuel consumption when in use.

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