Featured Hyundai IONIQ - Prius competitor?

hm, thats even more confusing since it says CAFE and not EPA.
http://www3.epa.gov/fueleconomy/documents/420b14015.pdf

CAFE results are usually 20%-25% less than EPA, so how can it be CAFE? Different tests two, 5 cycle vs 2cycle.
So it cant be CAFE since combined G3 rating in Korea is between two Ioniq ratings. They might apply their own corrections to CAFE or possibly actually use EPA tests with that website being wrong. Both Camry Hybrid and G3 Korean tests are very close to EPA ratings.




Merged

start stop uses larger starter like in every vehicle that has start and stop (most in Europe these days), it is not a two motor system and Hyundai is specifically calling it single motor system.

 

I've read about it a bit. It seems weird that Ioniq will supposedly use belt for HSG too.... It's 10kW on Sonata and will probably be the same on the Ioniq. The more I read about this Hyundai system the more sceptical I am becoming.

Let me check if I got it right:
- Since you have 2 motors about the same power of the ones in the Prius you still need the same size inverter and electronics.
- Instead of planetary gearset (quite simple) there is a rather complicated dual clutch 6 speed automatic gearbox that might be slightly more efficient on the highway (or about the same as 2016 Prius)

In images that is:

Toyota PSD (note: both motors included in the picture)


Hyundai Ioniq:
(only image I could find of Hyundai DCT)

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one more quite powerful motor (integrated into gearbox?)

Seems quite complicated from the mechanical standpoint.




merged

If it's one motor system, how do they spin up the motor when you are cruising on the electric if that one motor is between the clutch and the engine?

 

Being complicated doesn't make a DCT inefficient.

 

In an interview with AutoNews, Hyundai's R&D chief said this:

So that should end comparisons (including mine) to Hyundai's 2-motor Sonata hybrid system. In the same interview, Woong-chul said it would have a 6-sp DCT. (so 3 clutches altogether, I guess). I'm more inclined to think that the hybrid will be very similar to Honda's i-DCD 1-motor hybrid system used on the Fit that austingreen alluded to several pages back. That's a brilliant system that Honda has denied the North American market. Honda's system uses a DCT but not a third clutch, though. The link that austingreen gave shows details on how Honda uses a 1-motor system to start the engine and power the wheels, sort of: Honda Worldwide | Technology Picture Book | Sport Hybrid i-DCD I noted with interest that the video posted a few pages back shows Ioniq engine RPM at 0 with 80kmh on the speedo, so the motor can accelerate the car that fast before waking the engine.

 

10 kw + 35 kw = 45 kw. The gen III prius has mg2 of 60kw + mg1 of 42 kw IIRC or 102 kw of motors much more substantial than the ioniq. I think the gen IV are rated sligtly lower. The prius needs beefier electronics but really its not too bad. The benefit of the hyundai type system is when motor power goes up, hsd needs to scale (look at Lexus LS) which adds weight fast). In the prius/ioniq hp range (95, 105) its really not bad. The ioniq has a more powerful battery and higher usable energy which adds some costs, but probably less than that extra motor cost.

On any selected gear, a dual clutch is very simple. Control logic on when to swich is complicated as it is on the hsd. The dual clutch transmission is more expensive than the psd, but it saves on motor and inverter costs. We will see on pricing which comes out better.

DCT transmissions are considered more luxurious than cvt type transmissions like the hsd. There is not that rubber banding. That said the existing 5 year old hyundai dct is not nearly as good as a bmw or a porsche dct transmission. We will have to wait for reviews to see how they did, and pricing to see what it cost.

Sure and hsd is much more complicated than a manual transmission. Some times complication is needed.

The dct system that hyundai, vw, and bmw are choices. In an econobox I would say a hsd is a better choice simply because ford and toyota have worked out a lot of the kinks and costs, and have high reliability when you stay low power (Lexus ish @220 hp is the highest power before these things get much more expensive in the LGSh, LLSh).

DCT keeps getting less expensive and better. You really can't beat it for control or shifting speed with high efficiency. CVT are less efficient, but keep the engine in the most efficient range, and provide best 0-x accleration for a given power.

I'm glad hyundai is getting serious in the hybrid game, and I expect the competition will push performance up and prices to drivers down.

 

I drove the GTE and didn't quite like it. Slow gas picup when engine is off - about 2x slower pickup than Prius - and changing gears seemed weird to me in a hybrid. Also, that thing is quite expensive for a Golf starting at 42k USD. I really hope that Hyundai gets pricing right. Auris hybrid wagon is at the 22k USD in Europe, so if they can make it in about 15-20k USD range in Europe then that would be competition. But I doubt it since there has been some talk about 19k usd in usa, meaning it will likely translate to 26k or so in Europe as cars tend to be more expensive here.

 

That never actually addressed my inquiry. In fact, we just confirmed there is only 1 motor used for propulsion/generation.

When Prius operates, the traction motor (MG2) can be fed directly by electricity generated on-the-fly by the second motor (MG1). It also tops off the battery-pack when more electricity is generated than what is needed at the moment. A single motor system couldn't do either.

With limits that Prius doesn't have, how will Ioniq keep efficiency high in city & suburb driving?

Same question, since that efficiency is related to non-hybrid systems. When electricity usage is introduced, the equation is altered.

 

Yeah, it's as if Toyota quoted the efficiency for the planetary gear alone - that one would be quite high too.

 

I think my explanation just was not understandable to you. Think about the toyota system without the battery charge/discharge. It acts like CVT with mg1/mg2 as a torque converter. The prius decides the "gear" (engine rpm) and mg1 generates power and feeds it to mg2 to transfer torque, or viceversa in heretical mode, or no power when the prius picks exactly the ratio of the psd. Functionally mg1/mg2 also act as a regen or traction motor of approximately 27 kw in the gen 3 prius. So we can think of the hsd as a CVT plus a single 27 kw motor. Part of the magic is how well the prius's electronics select the proper engine rpm. A DCT functionally looks like a manual transmission but with electronics selecting gears if the driver doesn't, and a very fast clutch (60ms to switch gears for the systems in a porsche or bmw). If the hybrid electronics select the right gear it is pretty much like the prius system. That 35 kw motor clutched between the transmission and engine it can provide power from the battery or regen brake. It looks small but is effectively slightly bigger than the effective motor in the prius.

In order to get the dct effective takes a lot of electronics there were very expensive when the prius was new, but costs are coming down. When a shift happens, the dct switches clutches to the preselected gear, while this happens the engine rpm changes to max that new gear when it is clutched in. With a motor clutched to the engine, this should be easier than it is in a porsche or a race car, as that motor has easier rpm control. The other trick here is if the engine is off, it needs to start and increase speed to that of the transmission.

So the big difference is cvt versus dct. CVT's are usually more efficient during acceleration from low speeds. DCTs more efficient at high speeds and during steady driving. YMMV. If all you are doing is hitting stop lights, and you are jack rabbiting between them, that cvt will be more efficient. If you are on cruise control at any speed over 20 mph the dct will be more efficient. The dct will probably be easier to hypermile. For 0-60 though you will need slightly more engine power.

Regen braking will help both, when the power is used for accelleration.

 

In The Prius That Shook The World, Toyota looked at several approaches and a single motor is credible:

• MG1-MG2 power flow is bi-directional
  • normal mode, MG1 -> MG2
  • heretical mode, MG2 -> MG1 to provide counter-torque to 'load the engine' (aka., Prius overdrive)
• Single motor system can have multidirectional power flow
  • engine+motor drives the wheels
  • engine-motor_generator drives the wheels, heretical mode equivalent via battery
  • motor drives the wheels

The technical challenge for a single motor is to make it smooth. These single motor state changes involve an engine and stepped gear transmission. Making that collection of moving parts work smooth is what I call a hard problem . . . at least to me. The problem is the engine may have to run in inefficient modes and that leads to a concern we both share:

The single motor, Honda Insights all suffered from worse City over Highway mileage. At the time, I thought it was because the motor was built into the flywheel so the engine always had to turn . . . there was no true EV mode without engine overhead. The multi-clutch systems promise to remove the engine overhead when in 'motor drives the wheels' but there is a problem, engine latency.

My experience is starting an engine, going from 0-1,000 rpm, takes time measured in just under 100 ms. Worse, putting a load on the engine during this phase risks misfires. In contrast, the two motor, Prius system allows MG1 to handle it solo with many times the power of a traditional 12 V starter motor. Smoothing the engine start with a single motor is a hard problem and I am not be surprised that the IONIQ alternator is actually a motor generator . . . and then you're on a path that leads to where the Prius was pre-1997.

Anyone who has followed the CleanMPG stunts knows shutting off the engine while the car is in motion works. Just it tends to have other problems and we've not seen commercial cars doing that today. We've not even seen this implemented as an after-market, automated system, suggesting it is a hard problem with safety issues. But we'll see . . . once the car gets into the USA market and we have EPA metrics.

Bob Wilson

 

So in the end, is Ioniq one or two motor system?...confused...

 

I would call it 1.25-1.5 two motor because of the limited, 'claimed' function of the alternator/motor because the control laws, which are not known from the press-releases. That the chief engineer touts highway mileage and the Sonata is also a highway-high vehicle, I remain skeptical of their low-speed performance.

My description is my opinion and may or may not reflect the choices the Hyundai engineers took. We really need to have test articles in the hands of curious, engineer/technologists.

Bob Wilson

 

+1

exactly.

How well the dct is implemented will determine how often the engine will be at inefficient modes. We have not seen the bsfc of the hyundai engine, but my guess is it will have a large sweet spot for power like then gen III prius engine. Both the prius and hyundai system have the engine off to driving the wheels latency problems. Gen IV may have improved it for the prius. If you hypermile you probably won't notice it. Hyundai may have an additional factor of a gear down shift, but driver has control and if it has paddle shifters can shift and accelerate at the same time adding to driver "fun to drive" factor. I think this system gets rid of most of the problems of the honda ima with the more powerful battery here and extra clutch. These things add cost though, so we will have to see how the hyundai is priced.

I think I'm missing something here. The motor in the hyundai can unclutch and spin the engine up before re engaging with the transmission. I don't think the mg1 system has an advantage here, but you do have the time delay to clutch in. Like I said with a bmw or porsche its about 60 ms for a clutch unclutch, I don't think this is a big deal. The hyundai battery has more usable charge, and perhaps will be used more to assist the engine during these engine off to engine engaged transitions. Agree its possible that the new car has a 10kw mg that acts as a starter/alternator, but also it could use the single motor to do it all if it can get around honda's patents. IMHO it wold be better with the starter mg like the sonata hybrid, but going to only one would save costs.

Exactly. This should have much more sophisticated electronics (read more expensive and work better) than cars not designed to engine off. There is also a fairly big battery there to run the AC and other functions to keep the engine off longer, honda undersized the battery in their old system.

 

Let's not forget about non-propulsion efficiency... ELECTRIC A/C

Having less electricity available (due to clutch/startup/engine tradeoffs) would impact overall MPG.

Do the Hyundai systems include that or is it still engine powered?

 

This is a hv/phev/bev design so it would have to have electronic power steering and air conditioning just like the prius.

I don't think this is a big impact but the prius has less electricity available. The ioniq probably will use more electricity SOC and is designed for it.

I don't think the hyundai system was ever engine powered, but don't know for sure. you are thinking about the honda system in the insight and civic. The hyundai has a more powerful and more efficient engine, a more powerful and higher capacity traction battery, and an additional clutch to remove lots of the ima limitations. Honda is working on yet anouther system to over come past limitations. The system in the accord also removed the ima limitations but it was too expensive to work well in the market and is in a hiatus for a redesign.

 

Again, what is the source of that electricity?

Prius is a persistent design, generating electricity 100% of the time the engine runs. Overall, that has resulted in less energy waste than other systems.

Is the alternator doing double-duty, feeding both engine & battery-pack? That's a parasitic draw rather than power-balance. It's likely smaller too.

 

It is generated in the 35 kw mg, either from engine power or from regen braking. The lithium polymer battery acts as a buffer.

Most of this electricity is used as a torque converter, flowing from mg1 to mg2 or viceversa. That is how a psd with a single gear ratio can act as a cvt. Mg1/mg2 are sized mainly as a torque converter, with mg2 a little larger to be able to add power from the battery.

The combination of mg1/mg2 also can feed electricity to the battery or electronics, they at together like a smaller motor than than in the ioniq. Most of the motor size is used as a torque converter in the hsd system.

In the 2016 sonata hybrid it would be used to feed the battery pack or electronics (like ac, radio, etc) only when the engine is unclutched and the battery is low. In the ioniq we have no idea if it is used at all That will wait for more of a reveal. It may even be missing in the ioniq, with the 35 kw mg decluting if the car is in motion to start it, but that is an extra little dance that the sonata doesn't have to do, and honda may have protected with patents.

 

That alternator generator has been 10kW on the Sonata (yes, I do not know if this will have anything to do with it but just discussing), and belt driven meaning that probably there is no control over the rpm of that alternator nor the ability to turn it off which would mean you are right about that parasitic draw.

But as austingreen mentioned above, we don't have ANY details.
So far sounds too good to not have a catch. Some other manufacturers have done a similar thing to what Hyundai is doing now and it hasn't turned out that well - rather okay but not too great.


Merged.


Nice comparison in this review, made me scratch my head. So is Ioniq now Prius v (lowercase v for the Prius v wagon) competitor? If so beating it in the mpg compartment would be easier than the regular Prius (source):

"The Ioniq's sticker price is said to range from $19,100 to $23,006, which is lower than the $31,943 selling price of the Toyota Prius v (lowercase v for the Prius v wagon) in South Korea. "

 

I'm not sold on DCT. I keep thinking if VW DSG and huge failure rate. Gotta change oil a lot and still may fail.

I will take Toyotas system any day. Proven and probably the lowest failure rate of any transmission made.


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