60 replies to this topic

[saudoso]

http://mobile.reuter..._source=twitter

[Canuck]

 

 

In real-driving conditions, the French carmaker's 0.9-litre gasoline H4Bt injects excess fuel to prevent overheating, resulting in...

I admit to being rather surprised by that statement. That sounds so...bailing wire and duct-tape.

[PJGD]

But I thought that all SI gasoline engines are calibrated to go rich under high load; that's what "off-cycle" emissions are all about, right? How else to get the power that Marketing want without burning the engine up or having to go to exotic materials?

 

Indeed, that is in part why we have the diesel issues that we do at present; the diesel calibrators figured that if the gasoline guys can get away with off-cycle emissions, then so can we - but then they pushed it too far.

[malbear]

the answer is get rid of the exhaust valves that get too hot creating high nox and run a may fireball type combustion chamber with rich on the out side and stociometric in the center,. use a Beare Head 

[Canuck]

If only we knew a guy...

[Greg Locock]

Excess fuel to cool the exhaust valves and (ahem) the cat at high power has been a standard trick in the book for decades.

[Canuck]

Is that typical for around-town driving, sustained high-load operation, acceleration? The way the quote was written in the article, it makes it sound like the thing operates at such a high load that it requires it most of the time (as opposed to say during/immediately post hard accel).

[PJGD]

I am not a calibrator, but I think that you will find that under the modest acceleration loads required by the NEDC cycle that they are able to run at stoich in all areas of the test envelope, but in real world driving with the stop light drag race, they have to go rich; hence you have off-cycle emissions.  I assume the same applies when driving under sustained load in the Alps.  As Greg points out, this has been SOP for many many years.

[gruntguru]

The future of IC engines is lean-burn. Near-stoich operation generates the highest combustion and exhaust temperatures. So far, makers have needed to run stoich to stay in the 3-way cat window but far-lean operation has the potential to reduce engine-out NOx sufficiently to eliminate the reduction catalyst. Mahle TJI (as used by Ferrari F1 . . and others?) is an example.

[Lee Nicolle]

This is hardly news, I thought most people knew that these small inefficient engines were strictly to pass the lab  tests. Primarily for lab test mpg. Larger engines will always be more efficient and in real world terms generally are better than the baby engines. Though I suspect most of them also are fuel rich too cool the valves and stop pistons melting.

In the early days, late 70s so many engines small and large burnt valves and wore out guides and SUCKED fuel to be so called clean. They would have lasted about 10000km if they were not guzzling fuel

[Charlieman]

The future of IC engines is lean-burn.

The future of IC engines is lean-burn. And variable valve timing. And variable everything -- ignition, injection, compression... What about those smart engines/ICUs which cut out injection at close to idling speed? 

 

The future is something...

[malbear]

How about a considerable amount of air bypass so that what comes out of the end of the exhaust is so diluted with air that the measurements pass every requirement 

[Charlieman]

How about a considerable amount of air bypass so that what comes out of the end of the exhaust is so diluted with air that the measurements pass every requirement 

I believe that some cars used that system. But we are talking about "recycling" systems used in the 1970s and 1980s. It is 2016.

[malbear]

I believe that some cars used that system. But we are talking about "recycling" systems used in the 1970s and 1980s. It is 2016.

yes you are correct , here is a link 

http://what-when-how...stem-automobile

[gruntguru]

 

How about a considerable amount of air bypass so that what comes out of the end of the exhaust is so diluted with air that the measurements pass every requirement 

No. The standards measure the total mass of each pollutant and express the results in g/km (or g/mile or g/ton.mile).

 

Air pump systems were designed to oxidise CO and HC in the exhaust port - not to dilute.

[Lee Nicolle]

No. The standards measure the total mass of each pollutant and express the results in g/km (or g/mile or g/ton.mile).

 

Air pump systems were designed to oxidise CO and HC in the exhaust port - not to dilute.

They do both. 70s and early 80s had lots of air pumps. Which froze up in a few years and were often unavailable to buy.

[gruntguru]

 

They do both.

Yes of course they dilute - so does the atmosphere when the exhaust emerges from the tailpipe - at much lower cost (zero) than an air pump system.

[WhiteBlue]

The emission scandal practise allowed an excess of power which cannot be reached by some engines under normal testing conditions. There are different ways to claw this back. More efficient power regeration and hybrids that claim electric power back from the exhaust as well as from braking. It will not stop the basic turbo powered downsizing. Compared to non turbo times. To reach the necessary efficiency limits turbo charging is unavoidable. At least this is true for mass transportation. Luxury vehicles willbe another issue. They may get away with gas guzzling for some time but even SUVs and sports cars (BMW i8) will go turbo charged hybrid.

[mariner]

This report on the next Gm/Vauxhall full size Insignia confirms that GM have adjusted the size of their new engine up a bit to reflect the new testing.

 

http://www.autocar.c...rototype-review

[gruntguru]

A real-world emissions test (with some high loads) will advantage won't disadvantage diesel engines. Diesels do their best work at high loads.

Edited by gruntguru, 01 November 2016 - 01:35.

[Greg Locock]

But the typical duty cycle is dominated by  idle and 15 hp is it not?

 

 

Check out figure 8 in this http://www.nrel.gov/..._permission.pdf

[gruntguru]

Poorly worded. Fixed now.

[Briancoat]

There is more to this than where the Diesel works best, speed/load-wise.

As an example, one of Diesel's key advantages vs SI is lower pumping work at light loads due to the absence of throttling. A higher load cycle diminishes this advantage.

Published data (e.g. EQUA database) confirms that, as a passenger car fleet, Diesels have a bigger real-world-to-EU-certified fuel economy gap than SI.

Edited by Briancoat, 01 November 2016 - 10:41.

[gruntguru]

Point is, Diesel has always held that advantage, with current cycles for emissions and economy predominately running light loads. If future tests include some full load operation, SI - especially the downsized ones - will suffer greatly while diesels will not. If current diesels are poor performers at full load it won't be difficult to improve them - just look at heavy duty diesels and where they are most efficient.

Edited by gruntguru, 01 November 2016 - 22:32.

[imaginesix]

A real-world emissions test (with some high loads) will advantage won't disadvantage diesel engines. Diesels do their best work at high loads.

Or more precisely, will reduce the disadvantage of diesels?

[Briancoat]

Point is, Diesel has always held that advantage, with current cycles for emissions and economy predominately running light loads. If future tests include some full load operation, SI - especially the downsized ones - will suffer greatly while diesels will not. If current diesels are poor performers at full load it won't be difficult to improve them - just look at heavy duty diesels and where they are most efficient.

Hmm. Look at some real TDI & SI fuel maps and the new test regime and see if you still agree with "SI ... will suffer greatly while diesels will not".

[gruntguru]

I guess NOx becomes the problem - for diesels at least? Certainly not fuel efficiency.

[Briancoat]

Yes, NOx will be an issue - the Real Driving Emissions regs were formulated specifically to address Diesel NOx.

Re: fuel efficiency, here is some info.

This is from 100s of mobile emissions tests on different models.



The Diesels get proportionately more worse when subjected to higher load real world driving.

[saudoso]

Fuel efficiency was an issue with the barrel reaching $200. When it fails to hold on to $50 no one really cares.

[gruntguru]

 

Re: fuel efficiency, here is some info.

This is from 100s of mobile emissions tests on different models.

 

The hybrid result is hilarious.

From 2015 to 2016 the official Mpg improved 20%!!

Real-world Mpg declined by 2.4%!!

[munks]

I'm just trying to figure out what gasoline car is advertised as getting 50 mpg, much less that being the average of 100s of models ... ? Or is "Mpg" something different than "mpg"?

[Charlieman]

The website http://www.real-driving-emissions.eu is a bit of a shocker. It's an annual conference conducted in October 2016 for the fourth time.

 

Whilst you read the summary biog of a contributor to a recent conference, the list is abruptly updated. Try reading all four biogs before the flip.

 

And text is centre justified for no purpose.

 

These may seem petty points. But they challenge trust. To trust content of real-driving-emissions.eu, every internal link on the site has to work. All of the "sponsors and exhibitors" at http://www.real-driv...u/opportunities have disappeared. The people who paid for a conference don't matter. 

[Greg Locock]

The source of that unbelievable graphic is http://equaindex.com...-economy-index/ which doesn't explain it. I'm guessing they are using the useless European fuel consumption figures, but how that gets to mpg is anybody's guess.

[Briancoat]

Greg, Yes that is the source, I sort of referred to it in my first post. Thanks for posting the link. I think they've averaged the deltas they generated to get the bars but I don't think it is a true volume weighted fleet average.

Munks: Re: petrol cert figures at fairly high mpg. I assumed their testing is biased to smaller cars... I'll ask them.

I also assumed the relatively large sample size will mostly mitigate the inherent variability in a non-lab test, as far as their average figures go.

I must admit, there could be a number of other factors in the data, eg petrol cars tend to be smaller. I'm not interested enough to download their raw data set to crunch in Minitab and find out though.

Edited by Briancoat, 04 November 2016 - 11:42.

[Robin Fairservice]

Perhaps those numbers are from using US gallons!

[gruntguru]

You mean UK gallons? (They're bigger.)

[Greg Locock]

Even if they are Imperial gallons, I don't know what fleet of SI cars would produce an average test mpg of 50.1 mpg. That's 5.6 l/100km. Their website is no help. I suppose if you took C cars and smaller it would be believable. Mind you the real world figure of 7.1 l/100 is believable for a fleet average, that is only a smidgen better than I get from an Ecoboost Falcon, which must be upper quartile for weight, based on proportion of vehicles sold or even models.

 

I've attached the data, as you can see B and C cars dominate the top 10

Top 10 Best-Selling Car Models in Europe in 2016 (First Half)

The following were the ten most-popular car models in the European Union during the first half of 2016 according to JATO figures:

  Model HY 2016 % Change 1 VW Golf 269,430 -2 2 Renault Clio 173,462 4 3 VW Polo 166,894 5 4 Ford Fiesta 159,534 -9 5 Opel / Vauxhall Corsa 147,494 -2 6 Peugeot 208 138,368 14 7 Opel / Vauxhall Astra 129,691 26 8 Nissan Qashqai 126,113 1 9 Skoda Octavia 121,297 9 10 Ford Focus 120,534 -6        

 

[malbear]

My old EL falcon costs about $24 au per 400k on gas about 37 liters so thats about 9.2 lt per 100k mostly cruising at 95 k just in the torque lockup 1500rpm

Edited by malbear, 05 November 2016 - 03:38.

[Greg Locock]

That's pretty good for an aftermarket LPG system.

[malbear]

yes I would like to get a liguid port injection but that would cost more than the car is worth . that could improve economy as it cools intake and makes it denser

will direct lpg injection become the norm as it is with petrol ?

Edited by malbear, 05 November 2016 - 10:38.

[Briancoat]

 

Even if they are Imperial gallons, I don't know what fleet of SI cars would produce an average test mpg of 50.1 mpg. That's 5.6 l/100km. Their website is no help. I suppose if you took C cars and smaller it would be believable. Mind you the real world figure of 7.1 l/100 is believable for a fleet average, that is only a smidgen better than I get from an Ecoboost Falcon, which must be upper quartile for weight, based on proportion of vehicles sold or even models.

 

I've attached the data, as you can see B and C cars dominate the top 10

Top 10 Best-Selling Car Models in Europe in 2016 (First Half)

The following were the ten most-popular car models in the European Union during the first half of 2016 according to JATO figures:

  Model HY 2016 % Change 1 VW Golf 269,430 -2 2 Renault Clio 173,462 4 3 VW Polo 166,894 5 4 Ford Fiesta 159,534 -9 5 Opel / Vauxhall Corsa 147,494 -2 6 Peugeot 208 138,368 14 7 Opel / Vauxhall Astra 129,691 26 8 Nissan Qashqai 126,113 1 9 Skoda Octavia 121,297 9 10 Ford Focus 120,534 -6        

 

 

I did check the fleet of currently certified petrol models and the average (unweighted for sales volume) is about 47 mpg. This includes models certified prior to 2016. So the 50 mpg figure for 2016-certified vehicles is plausible.

 

The fact that there are over 200 petrol vehicles currently certified at >60 mpg illustrates what a load of tosh the certified figures currently are.

 

Emissions Analytics who produce the real world test data advise that:

 

50mpg is the average certified level for petrol cars, with no skew towards low CO2 cars - they test a wide range of new cars as they

are launched.
 

They also confirmed that the biggest differences between NEDC tests and their cycle are higher acceleration, gradients and the absence of the NEDC procedure's loopholes. 

Edited by Briancoat, 08 November 2016 - 13:33.

[Greg Locock]

I hadn't realised how loopy the EU consumption figures were. What a  waste of time.

[Lee Nicolle]

That's pretty good for an aftermarket LPG system.

I have always found that aftermarket gas systems are thirsty and sometimes gutless as well. The best example was my 100 series 4500 Landcruiser with a big dollar system. Best about 450k on 90 litres, usually about 400k. Got 500 once highway on a cold day and a tail wind!! Even towing was not much different. Ok for a 2.5 tonne 4wd. Though 950km on 130l of petrol was still better.

My work ute, factory gas FG traytop with a big ugly but functional canopy is about 400k on 80 litres around the metro and about 500k open road.

A mate with the same vehicle but no canopy with mixed freeway and metro gets around the 500 mark most tanks.

LPG at best is a lottery and seemingly depends on fuel quality which is varied.

I have never got near Mals figures!

 

My observation is that LPG has runs its course.  They will not fit it to our new imported front drive prams. And the electronics are too high tech and nowhere to fit the tanks

Late falcons and Commodores have LPG direct injected, they are near obsolete now.

Not many LPG fitters left now,, 15 years ago they were in every suburb, even mobile ones.

Several new retail fuel outlets do not have LPG pumps at all which says it all. Ask how I know!!

Edited by Lee Nicolle, 09 November 2016 - 09:24.

[munks]

The fact that there are over 200 petrol vehicles currently certified at >60 mpg illustrates what a load of tosh the certified figures currently are.

Thanks. I was previously assuming these figures came from the U.S., where there's only 1 or 2 gasoline-powered cars that advertise >50mpg, and even that is only on the highway.

[malbear]

I have always found that aftermarket gas systems are thirsty and sometimes gutless as well. The best example was my 100 series 4500 Landcruiser with a big dollar system. Best about 450k on 90 litres, usually about 400k. Got 500 once highway on a cold day and a tail wind!! Even towing was not much different. Ok for a 2.5 tonne 4wd. Though 950km on 130l of petrol was still better.

My work ute, factory gas FG traytop with a big ugly but functional canopy is about 400k on 80 litres around the metro and about 500k open road.

A mate with the same vehicle but no canopy with mixed freeway and metro gets around the 500 mark most tanks.

LPG at best is a lottery and seemingly depends on fuel quality which is varied.

I have never got near Mals figures!

 

My observation is that LPG has runs its course.  They will not fit it to our new imported front drive prams. And the electronics are too high tech and nowhere to fit the tanks

Late falcons and Commodores have LPG direct injected, they are near obsolete now.

Not many LPG fitters left now,, 15 years ago they were in every suburb, even mobile ones.

Several new retail fuel outlets do not have LPG pumps at all which says it all. Ask how I know!!

I think it is because I live in the country and have just about all cruising and no stop start or heavy accelerations. also it runs a bit lean on LPG as it starts much easier on petrol . Ok how do you know we wont have LPG any more ?

Gut feel if you want to tow that boat or caravan then a little motor will not cut it as it will be overloaded and fuel consumption will be worse that an appropriate sized motor

Edited by malbear, 09 November 2016 - 20:33.

[Lee Nicolle]

Small engines in small cars should never tow a boat!! Even a tinny. And front drivers should never tow anything more than about half a tonne gross. They are blatantly unsafe and under sprung

I keep reading these obvious bogus consumption stickers on small cars. Anyone with any sense can see  they are not true. Maybe 50mpg pn the freeway at 60k.

As I said  some new petrol outlets here do not sell LPG.  Having nearly run out last week and went to 2 sites [both new]  before I found one with gas. 1 pump only. Also a new site.

 Nor do many sell E85 either. A local site that did was rebuilt and no E85. A friend has an E85 Commodore company car that really struggles to buy fuel. Does the last update VF even offer E85 now? I have a feeling not. I do not think they offer LPG either. and the dual fuel Commodores sold a lot of Commodores because fleet buyers would not cop LPG only. That Ford have offered for over 10 years.

And BA onwards Fords do not do LPG conversion well, noone has managed to unlock the ECU to make them run properly on both as well as the large IRS makes the boot a good deal smaller and about 50l useable is all you can fit.

I used to service a Magna TR V6 that too had problems on LPG. Air flow meters lasted a couple of weeks [explosions] then it was very rich on petrol

[J. Edlund]

I hadn't realised how loopy the EU consumption figures were. What a  waste of time.

 

EU consumption figures weren't that bad until about 10 years ago, when EU and its member countries introduced significant incentives for car manufacturers to find new and innovative ways to reduce the official fuel consumption (and the related CO2 emissions). Aside from fines based on average CO2 emissions for new cars, many countries also base the vehicle tax on CO2 emissions, so a car with a low official fuel consumption will be cheaper to own. Various subsidies have also been given to vehicles with CO2 emissions below certain limits. Car manufacturers responded to these subsidies by introducing "low emission" versions of their already existing car models (usually diesels), where a 150 g/km car suddenly was turned into a 119 g/km model by some minor tweaks. Usually these models show the largest discrepancies between real-world and test consumption figures.

[J. Edlund]

Point is, Diesel has always held that advantage, with current cycles for emissions and economy predominately running light loads. If future tests include some full load operation, SI - especially the downsized ones - will suffer greatly while diesels will not. If current diesels are poor performers at full load it won't be difficult to improve them - just look at heavy duty diesels and where they are most efficient.

 

Fuel consumption at higher loads isn't the problem with diesels, it's passing the NOx emissions tests. Obviously it can be done since heavy duty diesels already passes such tests. But these are also equipped with selective catalytic reduction and large capacity tanks for urea-solution. This means added cost for the car owner and possibly additional maintenance by filling up with urea between the regular service intervals.

[Briancoat]

I agree that NOx is the bigger problem.

And if you think real world fuel consumption is an issue just wait for real world Ad Blue consumption.

It won't just be a case of a possible top up between services.

Here are a manufacturer's caveat-laden figures.

http://www.volkswage...y/diesel/adblue

Lean GDI faces a similar challenge with NOx reduction.

Edited by Briancoat, 14 November 2016 - 13:35.

[malbear]

I agree that NOx is the bigger problem.

And if you think real world fuel consumption is an issue just wait for real world Ad Blue consumption.

It won't just be a case of a possible top up between services.

Here are a manufacturer's caveat-laden figures.

http://www.volkswage...y/diesel/adblue

Lean GDI faces a similar challenge with NOx reduction.

to help reduce NOx get rid of the hot exhaust valves in the combustion chamber . there is a solution