Why such poor emissions on Toyota Engine Elises/Exiges?
Discussion
Well, its about par for the course for a 1.8 petrol.
It might be lightweight and low frontal area but that doesnt count for so much under the test scheme some of which is done on a rolling road (stupid). It also has sticky tyres.
More generally we can say the way petrol is burnt at compression ration of 10:1 which is generally is not a good way to use the fuel (should be nearer 14:1), producing lots of heat but not so much power. People are working on ways to make petrol burn in the same way as Diesel, i.e. at higher extraction efficiency.
some ways:
HCCI - hard to control.
variable compression - expensive hardware.
mixing otto and atkinson cycles need very fancy VVT.
The Turbo/downsizing route is also a good one with a modular turbo to reduce lag, this reduces pumping efforts. The PSA / Mini engine has excellent CO2 stats for a "real world" current prod engine.
The next gen petrol engines will have some genuine big leaps towards Diesel.
It might be lightweight and low frontal area but that doesnt count for so much under the test scheme some of which is done on a rolling road (stupid). It also has sticky tyres.
More generally we can say the way petrol is burnt at compression ration of 10:1 which is generally is not a good way to use the fuel (should be nearer 14:1), producing lots of heat but not so much power. People are working on ways to make petrol burn in the same way as Diesel, i.e. at higher extraction efficiency.
some ways:
HCCI - hard to control.
variable compression - expensive hardware.
mixing otto and atkinson cycles need very fancy VVT.
The Turbo/downsizing route is also a good one with a modular turbo to reduce lag, this reduces pumping efforts. The PSA / Mini engine has excellent CO2 stats for a "real world" current prod engine.
The next gen petrol engines will have some genuine big leaps towards Diesel.
Thanks for that answer, Ben. I understand what you're saying and didn't realise the emissions tests were done on a rolling road 
, but somewhere the numbers still don't look right. I can understand the emissions being high for the VVTi models, but the basic S is only about 138bhp so 190g is just ridiculous. Something like a 5 cylinder turbo Focus ST only chucks out about 220g. Maybe you're right and the testing system is just massively biased against Lotus'. Interestingly, I notice Porsche has managed to fiddle the figures in their favour with their clever double clutch gearbox - 220-odd grams is rather good for a new 911 although about as close to reality as investment bankers bonuses.
, but somewhere the numbers still don't look right. I can understand the emissions being high for the VVTi models, but the basic S is only about 138bhp so 190g is just ridiculous. Something like a 5 cylinder turbo Focus ST only chucks out about 220g. Maybe you're right and the testing system is just massively biased against Lotus'. Interestingly, I notice Porsche has managed to fiddle the figures in their favour with their clever double clutch gearbox - 220-odd grams is rather good for a new 911 although about as close to reality as investment bankers bonuses. SonicHedgeHog said:
220-odd grams is rather good for a new 911 although about as close to reality as investment bankers bonuses.
The testing scheme right now is a joke, but id bet the EU will wise up and that will change pretty soon to a better and independent test.The Toyota petrol engines are a bit indifferent to be frank.
The VED CO2 rules are despised on PH, but the reality for folks at the "new technology coalface" trying to get manufacturers to adapt new technology, its completely revolutionised the discussion. VED CO2 will lead to much more technology for the punters. The basic car engine technology, exc emissions is unchanged for 90 years, pathetic!
bencollins said:
SonicHedgeHog said:
220-odd grams is rather good for a new 911 although about as close to reality as investment bankers bonuses.
The testing scheme right now is a joke, but id bet the EU will wise up and that will change pretty soon to a better and independent test.The Toyota petrol engines are a bit indifferent to be frank.
The VED CO2 rules are despised on PH, but the reality for folks at the "new technology coalface" trying to get manufacturers to adapt new technology, its completely revolutionised the discussion. VED CO2 will lead to much more technology for the punters. The basic car engine technology, exc emissions is unchanged for 90 years, pathetic!
not sure what your getting at here but the EU2/3/4/5 tests are 'independent'
the real issue is that since the 90's when CAT's were seen as the be-all solution, engines have had to me made/mapped to work with a CAT, which is NOT the best for CO2 figures, then consider that the higher CR you go (for efficiency and performance), the more NOx becomes an issue.
end of the day, engine development these days is all about meeting the ever stricter NOx/CO and HC limits, the upshot is that the CO2 figure will suffer.
other point, you cannot compare CO2 figures for an EU2 tested car with an EU3/4/5 tested car, the test is different for starters, and on top of that, a car mapped to meet EU3 will probably have a better CO2 figure than the same car mapped to meet EU4/5 (for example, the Nissan Navara in EU3 tune was 226g/Km, in EU4 trim, it's 264g/Km (with less power/torque)
I am sure if you re-tested a 111S (K) against EU4 or EU5, it would have a higher CO2 figure.
I can't help thinking that these ever stricter tests are massively missing the point as all the target's are a % of total exhaust emissions, so if your having to produce more total to get the % down, overall that's still an increase in absolute terms.
Edited by Scuffers on Tuesday 17th February 09:24
Cats are needed to reduce smog. Visit shanghai.
Current CO2 rating is crap and largely done in house which leads to fiddling.
A poor execution of a good idea IMO.
EU5 testing is something else.
http://www.dailymail.co.uk/news/article-567174/Eco...
"The official figures are based on laboratory tests conducted by the manufacturers, importers or independent test engineers. They are a big selling point in adverts and affect the levels of road tax paid.
Honda denied the Civic Hybrid was a "gimmick" and insisted its carbon emissions were lower than other fourdoor saloons.
A spokesman said: "The quoted figures are generated from standard Government tests so that customers have a benchmark to compare one car with another.
"They are done in laboratory conditions and do not necessarily reflect driving conditions.""
Current CO2 rating is crap and largely done in house which leads to fiddling.
A poor execution of a good idea IMO.
EU5 testing is something else.
http://www.dailymail.co.uk/news/article-567174/Eco...
"The official figures are based on laboratory tests conducted by the manufacturers, importers or independent test engineers. They are a big selling point in adverts and affect the levels of road tax paid.
Honda denied the Civic Hybrid was a "gimmick" and insisted its carbon emissions were lower than other fourdoor saloons.
A spokesman said: "The quoted figures are generated from standard Government tests so that customers have a benchmark to compare one car with another.
"They are done in laboratory conditions and do not necessarily reflect driving conditions.""
SonicHedgeHog said:
Thanks for that answer, Ben. I understand what you're saying and didn't realise the emissions tests were done on a rolling road , but somewhere the numbers still don't look right. I can understand the emissions being high for the VVTi models, but the basic S is only about 138bhp so 190g is just ridiculous. Something like a 5 cylinder turbo Focus ST only chucks out about 220g. Maybe you're right and the testing system is just massively biased against Lotus'. Interestingly, I notice Porsche has managed to fiddle the figures in their favour with their clever double clutch gearbox - 220-odd grams is rather good for a new 911 although about as close to reality as investment bankers bonuses.
Is it just a mapping issue in the Elise?As you say the S with a 1zz comes in at 196 g/km while an Avensis with the same engine+800 odd kg is around 177 g/km., but somewhere the numbers still don't look right. I can understand the emissions being high for the VVTi models, but the basic S is only about 138bhp so 190g is just ridiculous. Something like a 5 cylinder turbo Focus ST only chucks out about 220g. Maybe you're right and the testing system is just massively biased against Lotus'. Interestingly, I notice Porsche has managed to fiddle the figures in their favour with their clever double clutch gearbox - 220-odd grams is rather good for a new 911 although about as close to reality as investment bankers bonuses. (And the SC's C02 is lower than the R
)I just find it baffling why a c 850kg car has higher emmisions than a car that weighs double with the same engine???
Mind you,are'nt the 1zz/2zz's designs now getting on for 10 years old?
/Confused of Sussex
- Edit*Just read Scuffers reply properly
Edited by The Bandit on Tuesday 17th February 14:00
The Bandit said:
I just find it baffling why a c 850kg car has higher emmisions than a car that weighs double with the same engine???
Mind you,are'nt the 1zz/2zz's designs now getting on for 10 years old?
/Confused of Sussex
If it has been remapped, then probably that "instant throttle response" much loved is actually a rather crude dump of petrol that spikes emissions, that the Avensis avoids (just guessing).Mind you,are'nt the 1zz/2zz's designs now getting on for 10 years old?
/Confused of Sussex
But i agree with the OP and yourself. Dont really understand why it is so high on the S or how/why it takes 18 months for Lotus to bring out a low CO2 map version. Too busy spinning too many (Evora) plates to take care of the day to day sales business, is the probable answer. Likewise toyota too busy pratting about with limited resource lithium batteries to bring out downsized LP turbo engines with on demand ancillaries. Then again we should be working so there´s hyprocrisy all around
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