[AlanHo]

It's about time attention was given to the misleading "official" fuel consumption figures.



http://www.honestjohn.co.uk/news/miscellaneous/2012-02/honda-civic-hybrid-owner-wins-fuel-economy-case-in-california/

[Shambles]

Interesting. Thanks for the post, but it sounds like the "prosecution" didn't prepare their case very well.

Nice to see courts taking notice tho... someone should try that over here. AlanHo ?

[AlanHo]

Even if the verdict gets overturned - the story will have hit the media and drawn people's attention to the problem.

I am getting more than tired of seeing and hearing exaggerated claims from individuals about how frugal their cars are - without government figures adding to the confusion.

If the same people went fishing - their outlandish claims about their catch would at least be limited to the length of their arms.

Much as I would like to be the hero and take my i30 dealer to court for "letting me believe the official figures" - I cannot.

Firstly because I have always known the figures are unrealistic in the real world and it would be dishonest to claim I was duped

Second - one of the directors in our Hyundai dealership is an old friend of my wife and I - it just might strain the relationship a little and affect the deal on my next car....

[Dazzler]

I think 90% of car makers overstate their fuel economy 

Over here I think it is an independent body that generates the ADR fuel figure 

 Our Hybrid averages .4 LPH more than advertised (The CRDi was .7)  Both using the onboard computer figures which are around .2 under the actual by my reckoning...

[AlanHo]

This article about the situation in Europe may be worth a read.


http://cars.uk.msn.com/features/green-motoring/car-fuel-economy-the-truth-about-mpg

It includes this statement - which says it all

Mpg testing takes place in a laboratory with the car on a set of rollers known as a rolling road. A series of accelerating, braking and cruising drills are performed, designed to replicate different types of driving.

Equipment is attached to the car that precisely measures the exhaust gases that are released during the test. From this information, the official emissions ratings for the vehicle are calculated and fuel economy is determined

Note how short each test is - a total of about 6 miles for both tests which are carried out indoors, at 25*C, in still air - hence no wind resistance drag, on smooth rollers using a car specially prepared by the manufacturer. A long way removed from the real world don't you think.

[Dazzler]

That appears to be a good article Alan.. had a quick read (have a better look later) 

[Phil №❶]

Many years ago i used to ride a pushbike to school. The wind was always against me in the morning and due to convective heating during the day, against going home. So the effect of wind resistance is a significant factor to be considered in fuel consumption, I know. 

These tests are a load of rubbish IMO.

BTW

The wind example above was an early warning indicator on how cr*p my life was going to be in the future too. 

[Dazzler]

The wind example above was an early warning indicator on how cr*p my life was going to be in the future too. 

Gee you are having a bad day Phil...

Surely it is better since you got two i30's and became a member on here...? 

[AlanHo]

The new 2012 i30 to be launched in the UK next month has a choice of two 1.6 CRDi engines.

110PS develops 81kW (109 bhp) @ 4000 rpm
Torque 260 Nm @ 1900 to 2750 rpm
0-62 mph in 11.5 seconds
CO2 emissions 100 g/km
Combined fuel consumption 74.3 mpg (3.8 l/100km)

128PS develops 94kW (126 bhp) @ 4000 rpm
Torque 260 Nm @ 1900 to 2750 rpm (identical with 110PS engine)
0-62 mph in 10.9 seconds
CO2 emissions 100 g/km (identical with 110PS engine)
Combined fuel consumption 74.3 mpg (3.8 l/100km) (identical with 110PS engine)
It costs £400 more than the lower power engine

So my questions are:-

* How can the higher power engine accelerate the car quicker - but use no more fuel and give out the same emissions?  Surely extra energy is expended.

* Guessing that the extra power is derived from just engine mapping - why an extra £400?

* Why bother to produce the 110PS engine and complicate planning, manufacture, stocking and distribution if the 128PS engine really is just as frugal and in the same tax bracket?


It seems very strange to me. 

* How can the higher power engine accelerate the car quicker - but use no more fuel and give out the same emissions?  Surely extra energy is expended.

The fuel consumption test was not conducted during the acceleration tests. You would be correct: if the extra power is exploited it should use more fuel.

[AlanHo]

The fuel consumption test was not conducted during the acceleration tests. You would be correct: if the extra power is exploited it should use more fuel.

Not quite true

Urban Cycle
The urban test cycle is carried out in a laboratory at an ambient temperature of 20oC to 30oC on a rolling road from a cold start, i.e. the engine has not run for several hours. The cycle consists of a series of accelerations, steady speeds, decelerating and idling. Maximum speed is 31mph (50km/h), average speed 12mph (19km/h) and the distance covered is 2.5 miles (4km).

Extra-Urban Cycle
This cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving and the remainder accelerations, decelerations, and some idling. Maximum speed is 75mph (120km/h), average speed is 39mph (63 km/h) and the distance covered is 4.3miles (7km).

Combined Fuel Consumption Figure
The combined figure presented is for the urban and extra-urban cycle together. It is therefore an average of the two parts of the test, weighted by the distances covered in each part.

Ok, perhaps I should have said "exclusively". If the acceleration tests are a small part of the total then I'm assuming the difference will be too small to measure (at least within the precision used). An extended test using the extra power available will almost certainly show extra fuel use.

[AlanHo]

So if you are correct - and it happens that I entirely agree with you - Hyundai are guilty of knowingly publishing data for the 128PS engine that is even more unrealistic than the data for the 110PS engine.

I realise that the official test is misleading anyway - but Hyundai have compounded the distortion by leading people to believe that the higher powered engine is as economic as the less powerful one.

So if you are correct - and it happens that I entirely agree with you - Hyundai are guilty of knowingly publishing data for the 128PS engine that is even more unrealistic than the data for the 110PS engine.

I realise that the official test is misleading anyway - but Hyundai have compounded the distortion by leading people to believe that the higher powered engine is as economic as the less powerful one.

Yes, I guess on both counts... but I don't think the problem is with Hy but rather with the test, as you say. If the tests have been conducted correctly then you don't really expect Hy to publish their own less flattering results?   I don't have a problem with any car maker adhering to the rules.

In any case, the difference must be minimal going by the very similar specs for both engines.

[tla]

Here's a link to a test conducted by Popular Mechanics to see if they could match the US' EPA mileage test results: http://www.popularmechanics.com/cars/news/fuel-economy/mileage-moment-of-truth-we-put-40-mpg-claims-to-the-test-6651300

[Dazzler]

A positive story thanks tla 

[mjt57]

I think 90% of car makers overstate their fuel economy 

Over here I think it is an independent body that generates the ADR fuel figure 

 Our Hybrid averages .4 LPH more than advertised (The CRDi was .7)  Both using the onboard computer figures which are around .2 under the actual by my reckoning...

For the benefit of our overseas bretheren, the Australian Hyundai pamphlet claims 4.5l/100km for the diesel for "highway cycle".

My car's computer tells me that I'm getting around 5.5-5.6. However, my records (fill, odometer, etc) tell me that it's closer to 6l/100km.

And FWIW my 5 speed trippy consistently shows 4.2-4, highway driving and 4.7-8 overall. I have no trouble with the advertised specs. 

[Ultralights]

i find the fuel figures more of a guide to compare cars.  if all do the same test in a lab under the same conditions,  then its a pretty good comparison.
I think the Hyundai numbers a pretty close with the only difference being wind resitance,  i notice they test up to 120Kph in no wind labs, we all know there will be significant wind resistance in the real world, and in my case, the car is averaging between 0.5 and 1 L/100km over stated figures.  my average over the past 22,000 Kmk is 5.1L/100 km,   but i have little traffic and flat roads on my daily commute as i live and work on teh southern outer suburbs of sydney.