Quote:
Originally Posted by Hersbird
Any car could be tuned to use these kind of a/f ratios especially without EPA rules. That car says low CO2 but how's it's HC and NOX doing?
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Depends upon the engine's design parameters what its exhaust gas analysis graph will look like.
Typically, when you go richer than stoichiometric, your UBHC and CO increases, but your NOx decreases.
When you go leaner than stoichiometric, your UBHC and CO decreases, but your NOx increases... at least until you hit flammability limits and start skipping combustion events due to flame blowout... then your UBHC increases and your NOx decreases. Extending flammability limits (via better head design, better ignition method, flammability enhancers) extends the lean-burn range before UBHC increases and NOx decreases.
Knocking down high combustion temperatures with water vapor or water vapor / alcohol injection while burning lean knocks down NOx by absorbing the combustion temperature spikes that create NOx.
So ideally, if an engine ran lean while utilizing water vapor injection, it'd produce plenty of power and still have clean(er) emissions. Stoichiometric is a compromise brought about by limits in the ability to extend flammability limits and knock down NOx production.
[soapbox]
We don't worry about CO2, because CO2 isn't a pollutant, it's a natural part of the oxygen / carbon dioxide cycle and is necessary for life, not to mention it only comprises 0.04% of atmospheric gas. Don't believe the global warming "CO2 is gonna getcha!" alarmists... those leading that charge promulgate their tripe to try to get carbon exchanges set up, from which they'll profit handsomely (at the wallet-draining expense of everyone else)... the rest of the herd bleating the CO2 alarmism are just wanna-be intellectuals vomiting the soundbites they think will make them sound intelligent. CO2 levels have been orders of magnitude higher in the distant past, and life (and the planet) survived just fine... in fact, during one particular period about 485 million years ago, CO2 levels were approximately 17.5 times higher than today, solar output was nearly identical (less than a percent difference, according to researchers), and the planet slid into an ice age that lasted approximately a million years and killed approximately 49% of all life. Because CO2 is not a global warming gas... it's been proven that CO2 concentration
lags temperature change by 600 to 1000 years in every glacial and interglacial period ever studied. The major contributors to global warming or cooling are the same as they've always been... solar and orbital forcing. Care to guess what the current trends are for solar and orbital forcing? Yeah... at the precipice of sliding into an approximately 10,000 year cold period.
[/soapbox]