The catalytic converter conspiracy

reply to post by LastTraintoMemphis


Yes the "freon conspiracy" is another good one. Did you know DuPont actually "volunteered" the information that R12 was supposed to be so bad for the environment? They did this out of the overwhelming kindness of their pure hearts. It had absolutely nothing to do with the fact that their patent on R12 was running out that very same year, and they already had a patent on 134a waiting in the wings.

Did you also know that R12 was inert, and if it was released in the cab of your car it was basically harmless as long as the air wasn't saturated enough to asphixate you. 134a is toxic, and caustic to organic tissue, and will burn your lungs. But that's the green freaks agenda anyway, kill the people to save the planet. The perflourcarbons that were supposedly so bad in R12 are released by volcanic eruptions also. If man made R12 at all out capacity for 2000 years and released it directly into the atmosphere it would be equivalent to 30 seconds of what is released by a volcanic eruption. R12 was literally a fart in a whirlwind when it comes to perflourcarbon emissions. We used to use it to flash chill our beer.

When does 134a's patent expire about 2014-2015 isn't it? Let's watch and see if DuPont does it again, and voluntarily removes that horrible awful 134a for their newest environmentally safer refrigerant that they just got a new patent on. You know the one that melts flesh on contact.

Better yet lets put absorption refrigerators on our cars instead of compressor designs. That way we use the heat from the exhaust manifolds to cycle the system, and there are no moving parts, and no motive energy used from the engine. We just reclaim some of the vast waste heat to cool the car, and you get the same mileage whether you run the AC full blast or not. Oh wait... that actually makes sense. Congress would ban it immediately. Nevermind.

reply to post by rickyrrr


You are very correct rickyrrr. It aslo depends on where in the system the cat is placed. Most cars even with duals have a cross over tube that eliminates much of the need to have both pipes exactly the same length. There are few instances of true "tuned duals" I had a '67 Chevelle with tuned duals, and it sounded like butter. Took a pound of cat litter to take care of what happened in most men's shorts when they heard it.

Also I do not recommend actually physically removing the cat as the new ones really don't restrict flow much as has been mentioned. I advocate that the automobile industry in America specifically needs to follow suite from Mercedes, BMW, and other european car makers who are doing away with the cat, and handling emissions with better fuel, and timing tables with much success.

To modify an existing car to do away with the emissions waste is not an easy thing to do, and requires specialized equipment, and intimate knowledge of engine management systems. However if the vehicle was built without a cat, and designed to run without it from the factory it would be very easy for them.

I get the 30% from the average observed improvement when you properly "de-smog" most older cars.

Originally posted by LeaderOfProgress
reply to post by autowrench

 

OMG you are not portraying octane right. Octane is used as a spark knock reducing additive. If your timing is advance far enough you must use a higher octane fuel. What octane does is SLOW the rate at which fuel is burned. LOW OCTANE fuel is more flamable and burns faster.

If that is true, they why do planes use 105 octane for their engines? In my teenage years, gas was near 98 octane, and I don't know if you are old enough to remember the muscle cars of the 60s, but try running 87 octane in a big block 427 Chevy running dual quads and a Vortex mag. You would not even be able to start it! You are right about the ignition advance making spark knock, this was cured with digital ignition systems. I would bet that gas you get from the pumps today is no more than 70 octane or less, I find it hard to get any mileage at all on it with a normal car. I talk to people who live here who tell me their new cars only get 19 MPG with a 4 cylinder.

[edit on 5/17/10 by autowrench]

Originally posted by LeaderOfProgress
reply to post by autowrench

 

Yes there is impovements to be made on the ignition systms but it WILL NOT double the MPG. What it will do is allow for more consitent spark which in return at HIGH RPM's will give you more efficient fuel burn. At low RPM's you will see little to no difference. We have dyno tested these ignition systems to see the gains and there are only gains at HIGH RPM's which most drivers never do. If you were driving at those RPM's your las concern is MPG. FYI Platnium plugs suck. If you want a good plug get iridiums for a naturally aspirated engine. Taylor wires are much better than most their resistance per foot is the lowest we tested.

[edit on 16-5-2010 by LeaderOfProgress]

I disagree. Case in point. If a stock ignition system burns half the fuel, the rest being dealt with by the CAT, and I can upgrade the voltage to burn all of the fuel instead of only half, does that not double the mileage? Tell you what, I will not argue with you, I like my system fine, in my G-20 I can run all month on one fill up, and that is about to improve as soon as the HHO reactor is installed. By that way, I did mention the mileage falling in city driving. Nothing to be done there. Most of my driving is highway speeds. I am just trying to help people get better mileage and screw the oil companies. For those who like big oil, there is no help for you.

reply to post by Reevster


For your information, my tailpipe is now a gray color, it used to be coal black. Gas has not had lead in it for years. Lead was used to plate the valves, to keep them from burning and for lubrication purposes of the iron guides. Doesn't anyone read Hot Rod magazine anymore?

reply to post by Binder


Thanks, Binder, glad to see another wrench in here, we already have a lot of techs. A garage is sad to look at now, the customer pulls in and his car is hooked up to a computer, a readout is made, and some sensors are replaced. The techs never get their hand dirty. I began working on cars in 1967 in a service garage for an old man names Kaz. When a car came in with a problem, we have to diagnose the problem. A good diagnostician was in high demand in those days, and I made good money then. A new car could be bought for $5000 with a big block engine and 4 bl. carb, dual exhaust and a 4 on the floor that would do a quarter mile in 11 seconds flat. Burn the back tires off on demand. I go to be an expert at carburetors, which few mechanics knew about in those days, especially the famous Quadrajet. 27 adjustments on that baby, try that with your laptop. I also rebuilt Muncie and Borg-Warner 4 speeds for people, another high demand job, because people would strip the gears off the idler trying to "power shift." I grew up with dirty hands and now my fingers hardly work anymore. But I still remember how to set up a hot rod, that is something one never forgets.

Hi to all

hey OP?

I have keen interest in cars and an auto and an efi course under my belt just out of interest and the want to do work on my own car.

Catalytic convertors were brought out when the lead was taken out of 'super' we used to call it in Australia.

They are made of a honeycomb like substance which your exhaust gases pass through.
They are on cars because the lubricant that now replaces the lead in fuel is toxic. The air travels thru here and undergoes a chemical reaction to make it harmless

my Internet is a bit broken at the moment but I will come back tomorrow (when I pay the bill)

the internals of the cat are coated with I can't remember what, and the convert the gas

if you get these wet with petrol it melts them on the inside and block up your car. My other 1/2 is a mechanic and you know when a young guy comes in with something that isn't 'pulling like it should' the cat is often one of the first thing checked. Because a lit of people do not understand the role electronics play in their car, and if one thing is changed it on the entry (fuel/air) something has to be changed when it's burnt and doesn't get adjusted accordingly.

Rambling now, will be back with more tomorrow for you

I also am quite up to date on laws with emissions in the US. I have a 280zx (with efi problems) so I have read some amazing things done for the tests to be passed by the card.

Back tomorrow.

MM

reply to post by autowrench


When it comes to spark among other factors there is a little known concept called electron pump theory. Basically in a nutshell it states that the more free electrons you have in the mix the faster you produce OH- free radicals. If you don't know why that would be a good thing you need to do some research. HHO generators are thought to be a form of electron pump amongst other benefits. There is a guy writing his doctoral thesis for theoretical physics about it. Another form of electron pump would be an ozone generator. All these thing make long chain hydrocarbons break down faster, and release more energy upon ignition. Theoretically a more energetic spark would also act as a more localized electron pump to begin flame front propagation faster, and more uniform.

On the topic of spark. Platinum, and iridium plugs are not designed for performance. They are designed for longevity, and reliability. They are made to go 100K plus miles without being changed because people don't maintain their cars, and the auto industry was tasked with making cars that would maintain a certain pollution performance level for 100K miles with minimal upkeep. The best performing plug is a super cheapy copper plug. It wears out faster, but makes a hotter spark. If you really want the best performance, and mileage get the copper plugs. Unless your plugs are really hard to change. On some cars it is a major task. I would use iridiums in that situation. You will need to change copper plugs every 20K miles. Also drilling, and indexing the plugs will help a bit.

[edit on 17-5-2010 by Binder]

reply to post by staple


Yes, it's true! My son several years ago built a car. A 1980 Pontiac Bonneville with a 1976 455 cubic inch Oldsmobile big block. Took him 77 hours to engineer that big engine in that car, but he made it work. Headers and straight through exhaust with Cherry Bomb mufflers, holley 750 carb, MSD ignition, General Kenitics camshaft and Rhodes lifters. Running a modified Turbo 350 Hydromatic trans. This car passed Indiana emissions with flying colors, and would produce near 400 hp on the dyno. Sadly, the car was lost in a wreck two years ago, we still have the engine.

Clean burning is the key, not a lot of sensors and a faulty ECM. The car companies are in bed with Big Oil, get it? The corporations are all in this together. Time to bring them down.

reply to post by Binder

I know a guy who invented a relay for Ford that would basically last forever, not literally, but well beyond the service life of the vehicle. He was paid, thanked, signed a non-compete/non-disclosure, and the plans were filed away to never be seen again. You will never see his relay on a new Ford EVER. If cars never break, they can't sell new cars. It's called engineered obsolescence.

Yep, I remember a guy that invented a carburetor modification device that would produce 70 mpg on a V-8 engine. GM bought the patent and tech, and we never saw it again. You could order plans from Popular Mechanics magazine. Several men who have invented devices have been murdered too. It is in fact a very big conspiracy in the automotive world. Four cylinder cars in the 60s got good mileage, some got 50 mpg. I had a Plymouth Valiant that got 61 mpg. Show me any new, high tech car that does that. Oh yes, the engineers at GM and Ford could build engine that got this kind of mileage, but they are prevented from doing so. Remember Preston Tucker? He built the first safe car, that they ran him out of business.



[edit on 5/17/10 by autowrench]

reply to post by autowrench


I love the 455!!! My favorite engine. My dad had a trans am with one. Every tiny little mod you did to that engine was rewarded with huge power gains. That thing is an absolute beautiful beast. His had 6x heads, and a holley 850 cfm dual pumper, and got 17 city, and about 20 highway. Not bad for 475 bhp. It had 265 rear gears. He got pulled over one time for 185 in a 75. The cop didn't want to bother with the paper work to take him to jail so he ticketed him for 85 mph.

I have an IHC scout that had an old Borg-Warner. I rebuilt it 3 times before I got it right. I was screwing up the vacuum regulator. When I finally figured it out it was a total facepalm moment, DOH!!! Wish I had known you back then! Not an easy task at all. Now it has a 727 torqueflight, and I'm happier with it. Indestructable tranny. BTW my scout has a HHO gen on it, and gets 13 city, and 16 highway. Doesn't sound impressive unless you've owned a scout. Before it would pass anything, but a gas station.

Hey binder and autowrench, i'm an old-school gearhead too - I was almost born in a shop, me and my dad and uncles have built all kinds of different "machines" and everything yall are saying is spot-on. I have owned a '67 Chevy II Nova with the ironhorse 6cyl and 2spd powerglide and 3.53 gears, a '65 Stepside with the 3-on-the-tree and 4.11 stump-pullers, and numerous other vehicles from the 60's and 70's, a few from the early 80's.

The first thing me and my dad did was gut the cat and muffler or just completely remove the cat - pull the offender off, cut a square in the top, knock out the innards, braze it back and then WHAMMO!!! Instant 10-15hp and better mileage - not to mention the sound!!! My Nova and my Stepside ran straight pipes, but I grew up in a town with like 2 sheriffs and could "buy" my sticker, since the guy was a fellow wrench too.

These people saying it does no good either have not tried it or are just ignorant. Granted it may not work like it used to on newer vehicles, but I really see no reason to have a cat on modern vehicles. Great post, I always knew there was a reason we gutted those suckers....

Originally posted by toochaos4u
My dad and a relative disabled the CAT on one of my mom's cars. It was done for other purposes. than fuel economy though. It was a new late 80's model and the catalytic converter emitted fumes that smelled like rotten eggs. My parents were going to return the car because of the smell.

That rotten egg smell is the sign of when you need to replace the cat.

Types
[edit] Two-way

A two-way catalytic converter has two simultaneous tasks:

1. Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2
2. Oxidation of unburnt hydrocarbons (unburnt and partially-burnt fuel) to carbon dioxide and water: CxH2x+2 + [(3x+1)/2] O2 → xCO2 + (x+1) H2O (a combustion reaction)

This type of catalytic converter is widely used on diesel engines to reduce hydrocarbon and carbon monoxide emissions. They were also used on spark ignition (gasoline) engines in USA market automobiles through 1981, when the two-way converter's inability to control NOx led to its supersession by three-way converters.
[edit] Three-way

Since 1981, three-way catalytic converters have been used in vehicle emission control systems in North America and many other countries on roadgoing vehicles. A three-way catalytic converter has three simultaneous tasks:

1. Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx → xO2 + N2
2. Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2
3. Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + [(3x+1)/2]O2 → xCO2 + (x+1)H2O

These three reactions occur most efficiently when the catalytic converter receives exhaust from an engine running slightly above the stoichiometric point. This is between 14.6 and 14.8 parts air to 1 part fuel, by weight, for gasoline. The ratio for LPG, natural gas and ethanol fuels is slightly different, requiring modified fuel system settings when using those fuels. Generally, engines fitted with 3-way catalytic converters are equipped with a computerized closed-loop feedback fuel injection system employing one or more oxygen sensors, though early in the deployment of 3-way converters, carburetors equipped for feedback mixture control were used. While a 3-way catalyst can be used in an open-loop system, NOx reduction efficiency is low. Within a narrow fuel/air ratio band surrounding stoichiometry, conversion of all three pollutants is nearly complete. However, outside of that band, conversion efficiency falls off very rapidly. When there is more oxygen than required, then the system is said to be running lean, and the system is in oxidizing condition. In that case, the converter's two oxidizing reactions (oxidation of CO and hydrocarbons) are favoured, at the expense of the reducing reaction. When there is excessive fuel, then the engine is running rich. The reduction of NOx is favoured, at the expense of CO and HC oxidation.
[edit] Oxygen storage

Three-way catalytic converters can store oxygen from the exhaust gas stream, usually when the air fuel ratio goes lean[5]. When insufficient oxygen is available from the exhaust stream the stored oxygen is released and consumed. This happens either when oxygen derived from NOx reduction is unavailable or certain maneuvers such as hard acceleration enrich the mixture beyond the ability of the converter to compensate.
[edit] Unwanted reactions

Unwanted reactions can occur in the three-way catalyst, such as the formation of odiferous hydrogen sulfide and ammonia. Formation of each can be limited by modifications to the washcoat and precious metals used. It is difficult to eliminate these byproducts entirely. Sulfur-free or low-sulfur fuels eliminate or reduce hydrogen sulfide.

For example, when control of hydrogen sulfide emissions is desired, nickel or manganese is added to the washcoat. Both substances act to block the adsorption of sulfur by the washcoat. Hydrogen sulfide is formed when the washcoat has adsorbed sulfur during a low temperature part of the operating cycle, which is then released during the high temperature part of the cycle and the sulfur combines with HC.
[edit] For diesel engines

For compression-ignition (i.e., diesel) engines, the most commonly used catalytic converter is the diesel oxidation catalyst. This uses excess O2 (oxygen) in the exhaust gas stream to oxidize CO (carbon monoxide) to CO2 (carbon dioxide) and HC (hydrocarbons) to H2O (water) and CO2. These converters often reach 90% efficiency, virtually eliminating diesel odor and helping to reduce visible particulates (soot), however they are incapable of reducing NOx as chemical reactions always occur in the simplest possible way, and the existing O2 in the exhaust gas stream would react first.

To reduce NOx on a compression ignition engine, the chemical composition of the exhaust must first be changed. Two main techniques are used: selective catalytic reduction (SCR) and NOx (NOx) traps (or NOx Absorbers).

Diesel engine exhaust contains relatively high levels of particulate matter (soot), consisting in large part of elemental carbon. Catalytic converters cannot clean up elemental carbon, though they will remove up to 90% of the soluble organic fraction[citation needed], so particulates are cleaned up by a soot trap or diesel particulate filter (DPF). In the United States, all on-road heavy-duty vehicles powered by diesel and built after 1 January 2007 must be equipped with a catalytic converter and a diesel particulate filter.[6]

Instead of catalysis, a reagent such as ammonia pyrolyzed in situ from urea, is sometimes used to reduce the NOx into nitrogen.
[edit] For lean-burn engines

For lean burn spark ignition engines, an oxidation catalyst is used in the same manner as in a diesel engine.
[edit] Installation

Many vehicles have a pre-catalyst located close to the engine's exhaust manifold. This heats up quickly due to its proximity to the engine, and reduces cold-engine emissions by burning off hydrocarbons from the extra-rich mixture used in a cold engine.

Many three-way catalytic converters utilize an air injection tube between the first (NOx reduction) and second (HC and CO oxidation) biscuits of the converter. This tube is fed by a secondary air injection system. The injected air provides oxygen for the catalyst's oxidizing reaction. These systems also sometimes include an upstream air injector to admit oxygen to the exhaust system before it reaches the catalytic converter. This precleans the extra-rich exhaust from a cold engine, and helps bring the catalytic converter quickly up to operating temperature.

Some newer systems do not employ air injection. Instead, they provide a constantly varying mixture that quickly and continually cycles between lean and rich to keep the first catalyst (NOx reduction) from becoming oxygen loaded, and to keep the second catalyst (CO oxidization) sufficiently oxygen-saturated. They also utilize several oxygen sensors to monitor the exhaust, at least one before the catalytic converter for each bank of cylinders, and one after the converter. Some systems contain the reduction and oxidation functions separately rather than in a common housing.
[edit] Damage
[edit] Poisoning

Catalyst poisoning occurs when the catalytic converter is exposed to exhaust containing substances that coat the working surfaces, encapsulating the catalyst so that it cannot contact and treat the exhaust. The most notable contaminant is lead, so vehicles equipped with catalytic converters can only be run on unleaded gasoline. Other common catalyst poisons include manganese primarily from the gasoline additive MMT, and silicone which can enter the exhaust stream if the engine has a leak allowing coolant into the combustion chamber. Phosphorus is another catalyst contaminant. Although phosphorus is no longer used in gasoline, it (and zinc, another low-level catalyst contaminant) was until recently widely used in engine oil antiwear additives such as ZDDP. Beginning in 2006, a rapid phaseout of ZDDP in engine oils was begun.

Depending on the contaminant, catalyst poisoning can sometimes be reversed by running the engine under a very heavy load for an extended period of time. The increased exhaust temperature can sometimes liquefy or sublimate the contaminant, removing it from the catalytic surface.

en.wikipedia.org...

[edit on 17-5-2010 by porschedrifter]

A friend who is a mechanic, with about 30 years experience, has long warned me about the downsides to catalytic converters. His chief gripe appears to be with the fragility of the structure leading to heavy metal pollution.

He advises that the relatively fragile heavy metal matrix (e.g. platinum) can be easily shattered and degraded, especially on bumpy, pot-hole, or or speed-bump ridden roads, and thereafter is likely to blow particles/parts of said heavy metals out through the exhaust and into our environment. He thinks this is a very common if not certain phenomena.

Eventually, the matrix gets so shot that it will get picked up in the UK MOT test and changed, but by that point, you may have been blowing out heavy metals into the environment for some time.

His point is that this is a cumulative and apparently totally ignored phenomena - is anyone monitoring this impact on our environment? I would be interested if anyone else has come across this aspect.

EDIT: [So we made a big fuss about lead pollution and stamping that out, only to totally ignore subsequently splattering the environment with cat contents (other heavy metals etc.) What sense is there in that? Big bucks for the manufacturers though? Also whilst the cat is out of action, potentially when you hit a nasty bump the day after your MOT/cat test pass until the next (year) it's checked, it won't be doing it's full job on catching other pollutants either.]


[edit on 17-5-2010 by curioustype]

Originally posted by autowrench

Originally posted by LeaderOfProgress
reply to post by autowrench

 

OMG you are not portraying octane right. Octane is used as a spark knock reducing additive. If your timing is advance far enough you must use a higher octane fuel. What octane does is SLOW the rate at which fuel is burned. LOW OCTANE fuel is more flamable and burns faster.

If that is true, they way to planes use 105 octane for their engines? In my teenage years, gas was near 98 octane, and I don't know if you are old enough to remember the muscle cars of the 60s, but try running 87 octane in a big block 427 Chevy running dual quads and a Vortex mag. You would not even be able to start it! You are right about the ignition advance making spark knock, this was cured with digital ignition systems. I would bet that gas you get from the pumps today is no more than 70 octane or less, I find it hard to get any mileage at all on it with a normal car. I talk to people who live here who tell me their new cars only get 19 MPG with a 4 cylinder.

MPG is NOT affected by Octane ratings. Argue all you want but quality of gas ie, impurities will affect MPG long before Octane. I can tune a car to run on any octane gas. It is truely not a factor. Once again all octane does is reduce spark knock. Some cars get better MPG with more advanced timing if the PCM allows the timing to be advanced enough to take advantage. Take an SUV for example, my ford expedition eddie bauer edition 2004 model, runner high octane fuel decreases the MPG due to the PCM's inablility to advance the timing far enough to take advantage of it. Could this be tuned in? Yes if I want to spend 400 dollars on a tune and the extra cash on the high octane fuel. Now my 2005 GTO is another story. It has a pretty aggresive timing from the factory, due to this it needs the higher octane. We have logged countless hours with HPtuners with various fuel types, octane ratings, and even different fuel companies. You are argueing with real world results and experimentation. Ignition upgrades only affect higher RPM's you can argue this but thousands of dyno pulls later we know the results, ignition advantages come at higher RPM's period. We also did resitance test on every major wire we could the result were as stated previously.

The airplanes use 105 because that is what they are built to run. Airplanes run based on computer parameters like a car. They need the slower burning fuel so as to not cause pre detonations just like a car. Part of it is also based on the compression ratios also. If you are running a real high compression ratio say 13:1 then you will need higher octane just to prevent predetonations during the compression cycle. Airplanes do run at very high compression ratios and have very advanced timing. They always have. That is why they have always needed special fuel additives even since WW2.

[edit on 17-5-2010 by LeaderOfProgress]

the auto conspiracy...where do I start?

converters needed, no....remove them, potential for jail, violation of federal law...
and cars have such high emissions to start with because there is so much overlap in the cams
fuel injection SOOO much better than carbs......well, not if you know how a good carb works, and perform standard maintainance. (thermo-quads were the best, followed by quadrajets, all metering rod carbs, but surprise, you can't buy them anymore, and I don't mean the fake chinese look alikes, they are not THE SAME)
your tires now last way longer than they used to, NOT (WW2 tires lasted years on the army trucks)
bearings, suspension components are all sealed components that don't need greased...and wear out twice as fast and cost 5 times as much. (front bearings $12 vs $75)
the gasoline formula has changed again in the past 2 years. there is some kind of (I think) heavy alcohol (glycerin??) being added to regular that absorbs water and forms a pure white string like compound. (mid and super don't have it or much less)
most 5 & 6 speed automatics are only 4 speed ones from the 90's re-programed to wear out more gears by running some stuff backward and shifting more often
generally there is no such thing as an "un-optioned car, adding $$$$ to the minimum price
cash for clunkers, and artifically inflated scrap prices all have the good used parts crushed and sent to china
did you know most "junk yards are scraping parts over 5-8 years old?
all the older cars without bar codes that can be read from sats (check VIN angle) or on board external over-rides (OnStar) are getting harder to inspect, insure and reg.
Did you know, with saturn out of business, you can not purchase any dealer only parts?...NONE (I suspect the other boys from GM are the same boat)
I drive a old dodge dart, /6, 3 speed manual. the car is unmodified, properly tuned, weighs in at 3800 lbs and gets 32 mpg and puts down 70 miles a day
breath, breath, rant over (for now)

dr

reply to post by Binder


Iridium plugs are the hottest burning plug out there period. Now I use copper but it is for different reasons. I run large amounts of nitrous through my car and would rather have a tip melt off of my plug and fail to spark then a hole burned through my piston. I use copper because they will fail due to inferior metals.

reply to post by Binder


Someone in my family works for one of the Big Three in a position fairly high up in the Powertrain division. I asked him what he thought about your post and he said "The argument to get rid of catalytic converters is a bit exagerated. Today's engine control strategy does run on a closed loop based on O2 feedback sensors in the exhaust which makes them run much closer to optimal stoichiametric mix. The problem is that the feedback sensors are still mostly discrete in nature and the strategies look for constant transitions from rich to lean. The reading is also just a representative average of all the cylinders. So you can still have a cylinder running rich and another running lean so it is not perfect. The other issue is that you have other non hydrocarbon emmissions controlled by the catalyst primarily Nitrogen Oxides. To get rid of the catalyst would require O2 sensing at each cylinder (very expensive) or very precise manufacturing of injectors, combustion chamber etc.. and still have no way to compensate over time. In short, we are not yet ready to eliminate the converters.

Originally posted by NoHomers
reply to post by Binder

 

Someone in my family works for one of the Big Three in a position fairly high up in the Powertrain division. I asked him what he thought about your post and he said "The argument to get rid of catalytic converters is a bit exagerated. Today's engine control strategy does run on a closed loop based on O2 feedback sensors in the exhaust which makes them run much closer to optimal stoichiametric mix. The problem is that the feedback sensors are still mostly discrete in nature and the strategies look for constant transitions from rich to lean. The reading is also just a representative average of all the cylinders. So you can still have a cylinder running rich and another running lean so it is not perfect. The other issue is that you have other non hydrocarbon emmissions controlled by the catalyst primarily Nitrogen Oxides. To get rid of the catalyst would require O2 sensing at each cylinder (very expensive) or very precise manufacturing of injectors, combustion chamber etc.. and still have no way to compensate over time. In short, we are not yet ready to eliminate the converters.

You are correct in saying that the O2 makes a bulk representation of the engine dynamics. But there are very precise injectors it just that the car manufacturers do not want to pay for flow matched injectors. Where do you get the idea that in order to get rid of the cat you must have an O2 sensor per cylinder? The cat has no function to the engine except converting noxious molecules to less noxious molecules. The O2 sensors after the cat are not a part of engine management.