Featured Hyundai IONIQ - Prius competitor?

The Lexus CT200h is about 3,130 pounds and the 2015 Prius is about 3,070 (2016 Prius is similar) so that's only a 60 pound difference.

The new Malibu hybrid is a much larger car and weighs about 3,460 pounds and also uses 17 inch tires but gets 47 mpg versus 42 mpg for the CT200h.

 

as we've seen with the eco two, a few pounds can make a big difference.

is it tuned for quicker acceleration?

 

Bob - I have been away, and was unable to get on the net in a timely basis.

Dumb question - in your chart several post back. What is "EV/ICE" expressed as a percentage? I tried to consider several possibilities, but alas, I decided it would be easier to ask.

 

Thanks for quoting this, it's new information for me, Ford Fusion H has not been a good seller in EU, on our forum we're still waiting for one!

About it: i could'nt find any evidence to clarify if Prius 4 have been tested, in 2015, with a "new" set of rules relative to the 2010 Prius. Can you help in giving some info?
And also, when new rules are issued, all previous test and stickers already done on existing models, must be re-tested and new stickers created?

Are you aware if In Korea, when new rules are issued, all previous test and stickers already done on existing models must be re-tested and new stickers created? The 49,4 mpg should'nt be a 2010 result?

In EU we have that unreal NEDC that does'nt give a clue, in actual fact, so we're always interested in EPA test results.

On a second tought, i went to have a look to those Michelin: the Energy Saver A/S seems to be the most efficient LRR on your market (but unfortunately you don't have any labeling, so i'm not sure if is hype) against the Primacy MXM that seems a tire for grip and luxury car. The 11% difference btw the to trim could be absolutely realistic.

I did experienced personally what does it means a big jump in tire RR class, passing from a crappy 17" (but excellent for grip) class E (Dunlop FastResponse) to class A, with the Toyo Nanoenergy 2; even if you reduce my 18% [edit: No, it's +21,7%...] improvement on fill-up results taking in account season and possible different use or whatever, the improvement it's huge:

Before AVE 48,9 MPG:
Gasoline consumption: Toyota - Auris Hybrid - Auris 2013 HSD Lounge - Spritmonitor.de

After: AVE 59,50 MPG
Gasoline consumption: Toyota - Auris Hybrid - Auris 2013 HSD Lounge - Spritmonitor.de

 

Its history goes back to 2001 when I was first looking a hybrids. At the time, there were two 5-seater choices, Gen-1 Prius and Honda Civic. So I noticed:

1. Honda system had higher Highway MPG than City
2. Toyota system had higher City MPG than Highway
3. Drag energy increases exponentially as the speed increases so City should be lower than Highway.

When I looked at the drivetrains, I noticed the EV/ICE power ratio was higher with the Toyota system and it was more efficient in the City. That rule of thumb remains true today and a percentage is an easy way to calculate their ratio.

Now I accept that the proper formula should be #1:

1. EV_hp / (EV_hp + ICE_hp) # the formal definition
2. EV_hp / ICE_hp # gives infinite efficiency if there is no ICE, a pure EV

Sometimes #2 is easier to calculate and the errors are easy to deal with. For example, the I3-REX works for #2 but the I3 suddenly becomes infinitely blessed. Recalculate the table and we get the same order.

Bob Wilson



I would like to agree but the absence of hard, engineering metrics for tire rolling resistance bothers me:

Tire pressure has a direct relationship with rolling drag so when I replaced my original tires, I went for the highest pressure related. Granted the ride is stiffer but tolerable.

The second factor is revolutions per mile. The 2010 has a built-in error of ~6%. So I put oversized tire whose revs/mile are ~5.5% larger and instantly reduced the odometer, speedometer, and MPG errors to less than 1%. I've never looked back but I understand this may not be an option in some countries. Running non-standard tires results in a violation and takes the car off the road.

Bob Wilson

 

I guess the standard 15" of Ioniq shows the same Prius ECO trick of inflated pressure.... we just got the info of the inflated pressure of Prius ECo by a single source, cause i don't think it's something Toyota is keen to advertize, soon or later i'm sure it will pop-up the same thing for Hyundai.

I'm saying that because i'm aware that huge improvement is possible when you make a large jump btw RRcoefficients, but for brand new cars in different tire size, i can't see such a huge jump as i've personally experimented.

Oh no, wait a minute, my class E were standard fit end of 2013

I might add that i could'nt inflate my Dunlop class "E" more than 2,7 bar, but i could, keeping a soft ride, with the comfortable Toyos, inflated at 3 bar.

 

This is where I documented the change: Sumitomo T4 195/65R15 vs. GPS | PriusChat

My original benchmarks showed the error:

In my original mph vs MPG tests, the indicated MPG was high. Later we (the community) found the indicated MPG was optimistic by 6%. So I added the second, thin line to reflect the bias. But after replacing the original tires, the new revs/mile put the car right on the numbers.

I am doing some advanced metrics that read out the speed from the ECUs and found there is a 6% error reported by the ECU, probably the brake controller. This is a latent defect in the 2010.

Bob Wilson

 

There are two primary test cycles for the EPA, city and highway, that are used for CAFE and emissions. There was a basic adjustment to these results to have a number closer to what drivers would expect on the window sticker. In 2008, they introduced 3 new test cycles; high speed, cold, and A/C use. These don't affect the results for CAFE and emissions, but are used to get a window sticker adjustment that reflects real world driving better.

The countries that adopted the EPA test may not have adopted the 2008 changes. Canada only did so recently. It appears Korea has done so, since the gen3 Prius results are close; 49.4 to 50 mpg combined. The EPA rounds away decimals, so the gen3 might actually be 49.5mpg or 50.4mpg. Either way, the difference we see could be within the deviation of test results, or simply due to conversion and rounding errors.

The test cycles aren't the only part of the test. There is a test to determine the load resistance to use on the dynanometer during the actual test cycles. This 'road load' reflects the car's aerodynamics and weight, along with tire rolling resistance. It was determined by a coast down test from 50mph. For 2016, which the gen4 is tested under, this has been changed to a coast down from 70mph.

There is also a set of rules covering the test car's condition, tire wear, and other minor things that can shift the results when taken together. All we really know about them for 2016 and up is that the EPA clarified them to reduce confusion. The fine Hyundai paid in the recent past seems to have been a misunderstanding of those rules.

So we have the Korean numbers for the gen3 that are close enough to the US number for us on an internet forum to say that it was the same test. The Ioniq has 52.7mpg combined under that test, and would have gotten 55mpg under Korea's old test. What we don't know is what the translation about the old test is actually referring too; is it to the pre-2008 test cycles, or the 2015 pre-testing rules? If the first, the Ioniq will likely do a little worse on the US tests; I'd say falling between the gen3 and gen4. If the latter, it will match or best the gen4 by a mpg or 2.

 

Others have pointed out it gets different numbers on 17" versus 15" tires. In contrast, the 2010 and the 2016 appear to give the same mileage with both 17" and 15" tires . . . per the EPA tests.

Bob Wilson

 

So no matter what trim level ioniq you buy,navigation must be standard as it seems its a vital part of their hybrid system !
I wonder how much it really does to increase efficiency because I am sure Toyota allready thought of the idea !

 

Thanks for your handy resumé Trollbait.

I'm totally aware of the relevance of the load applied in these tests, problem no different from testing of stand-alone engines. I've spent a lifetime as a mechanical engineer dealing with "loads" and engines, so i'm aware how test beds mimicks reality in a really approximate way. And learn how to make some trick to exploit all their possibilities and power....
You don't know the real possibilities of an engine looking at that hypothetical succession of stationary fictitious states, that is an engine curve coming from a test bed, and a whole car is no different if fitted with a manual gearbox. Just the max power is always a quite accurate estimate, not really any non-stationary condition. Automatic gearbox cars in that respect are more predictable anyway.
That's the reason why i would dream to test a car with one of those wonderful Atkinsons 40% efficiency with a variable load device, that is a manual gearbox... anyway that's an another story...

I understand.

Right.

 

Here's a handy writeup of South Korea's domestic fuel economy testing regulations:

South Korea: Light-duty: Fuel Economy and GHG - Transportpolicy.net

I remember reading something about a regulatory change in 2013 that was going to tighten up mpg calculations used in South Korea after Hyundai's US EPA scandal but now I'm having trouble finding evidence for such a change in 2013. I'll keep looking later tonight.

 

Only because the EPA rules don't require the results for differing tire sizes. These same rules also let Ford use the Fusion hybrid results for the C-Max.

The automaker is free to test different wheel sizes, and Toyota did for the Camry hybrid. The XLE/XSE with larger wheels gets worse economy than the LE. Compare Side-by-Side

 

And that was just a change from 16 inch to 17 inch wheels whereas for the Ioniq it was 15 vs 17.

If you look at the details on the Camry estimates, the city estimate dropped from 43 to 40 but the highway only dropped by 1 which implies the combined change was rounded down to 1 from something closer to 1.5. If you multiply that difference by 2 to account for the extra wheel size change it amounts to about a 7% difference.

If you apply that to the Ioniq's 52.7 mpg for the 15 inch wheels you get around 49 mpg instead of the actual Ioniq estimate of 48 mpg. Of course there may be other differences between the Camry trims that added weight but the same could be true of the Ioniq trims.

 

!!??!! You've just killed my love for EPA

I might add that EU Auris HSD (and Prius HSD too) stickers under NEDC 2013, shows the 15" at 3,7 lt/100km combined vs 3,9 lt/100km using 17", that is 5% difference. [EDIT: same RR class "E"]
If you take the Camry example averaging city+hwy (not the combined then), it gives the same 5%.
Other indications brings always an estimate btw 4 and 5% just for a difference 15-17 (with the same diameter of course).

So even if it's difficult to state anything in general because usually two different tire size could also be different tire models (and sometimes maker), i think we can say with no doubt that an EPA estimate unique for a 15 and a 17 is more than fishy, it's basically false.
If EPA allows you to decide the tire size, expect a Ioniq showing a sticker with only the results of the 15".....
And then: is it the 52 MPG combined of Prius IV achieved with the 15 or 17? There's any chance that mileage in Prius IV does'nt vary with such a stretch of tire size? I think, no way. Hypermilers better stay away from Tourings...

 

In Europe the gen. 4 Prius is rated 3.0 liters combined with 15 " wheels and 3.3 liters with the the 17 " wheels,but you have to consider that the 17" Versions have quite a bit more equipment on board !
The Top Version even usaly has absolutely everything the Prius has to offer depending on the country it's sold in .
In the US you have different packages,and don't seem to get every option available on a single car and that's probably why the 15 and 17 " wheels do not make such of a big differnece considering fuel economy .

 

You're messing up references: the 3,0 lt/100km in EU is related to the Prius ECO and the 3,3 lt/100km to the rest. Between the "rest", there are model with the 15" and models with the 17", loaded or barebone, all of them at the same FE.

So, for the moment beeing, the same situation of US with two ratings, one for the standout ECO model, and the other for both 15" and 17", which is unrealistic, also for the reason you mentioned, cars with different trims and accessories.

But those EU test ratings are preliminary and not too detailed, when the cars will be for sale in feb/march all trough EU, we eill know if, as in Italy, a double rating for the non-ECO will be available or not.

 

bisco - I haven't seen any recent post from you. Are you digging out from the snow? I hope all is well.

 

The EPA tests are the best at modeling what to expect on the road at this point. There are some loopholes that may have had a reasonable intent, but could be abused.

Ford was abusing the one which let the maker use the results of one car for another of the same weight and with the same drive train. The intent probably was to allow the company save on testing rebranded models; the Mercury and Lincoln versions of the Ford. Ford noticed the rule didn't specify body type being the same; so they used the Fusion hybrid for the C-Max results.

As too not testing the different tires. The rules allow using the results on the window sticker for the model from a vehicle equipped in the manner of what the majority off the factory line will be. I'd say this is from pick up trucks. In addition to engine choices and whether to get 4WD, buyers also have a choice of rear differential ratios. Testing all the possible combos would jump the 4 fuel economy listings from 4 to 12 or more for a model. In an about face from their hybrid testing behavior, Ford did do separate tests for the high gross weight versions of the new F150, which have steeper differential ratios than the rest of the line up.