A really dumb question: cars, exhaust & emissions

Beeman · #21 03/13/10, 01:41 PM

I'm like the canary in a coal mine. After too many decades of exposure to exhaust fumes it takes very little to make me ill. Late model vehicles do an incredibly good job of cleaning up the exhaust of the poisonous gasses.
Exhaust gas recirculation was done to remove oxides of nitrogen by intorducing an inert gas(exhaust) into the fuel/air mix. Many vehicles no longer use exhaust gas recirculation. Fuel injection can precisely meter the fuel from the feedback of the sensors and the catalysts can do such a good job of cleaning all of it up.

Just think if we kept going at the rate of driving but never cleaned cars up what a state our air would be. If you really want an education go find some early 70's articles about how air pollution from cars is a hoax.

**clovis** · #22 03/13/10, 04:05 PM

Quote:

Originally Posted by HermitJohn

In 90s Ford went to an 8 plug head design for their 2.3/2.5L 4cyl. And I thought it worked pretty good. Drove one many times that an elderly friend owned. Only thing ever went wrong on it was crank sensor which I replaced for him. Nissan had used simular setup starting in the 80s without a computer. I kinda liked those too. Dont think any of them had a spark plug in the exhaust. Now some of the 90s era cars I have monkeyed with had like 4 oxygen sensors. Goodness only knows why.....

Frankly I would say that most carb cars still on road arent tuned properly. Either detuned for arbitrary emissions standards at factory or the fuel changed and the carbs werent retuned/rejetted for the new fuel, or some heavy handed shade tree tried to "improve" things without really knowing what he was doing. Computer fuel injection cars can self tune to certain extent even as fuel characteristics change. Such as winter blend fuel vs summer blends. Or the cars that can burn upto 80 percent alcohol blends without manually changing anything.

In other words the computerized systems if so designed can adapt themselves whereas carb systems required human intervention to change to different conditions. And as long as the engine ran, few bothered to make those changes. In case of pollution carb vehicles, probably even illegal to make any unauthorized changes even if the fuel blends had changed. Burocracy is not a pretty thing and not necessarily very efficient or logical. They really want to eliminate old carb cars altogether I think and probably like to put computerized fuel management and a 3 way catalytic converter on your 3hp briggs lawn mower.

John,
The 8 plug Ranger must be what I was thinking about.

You are right about properly tuned carbs.

The day is coming on catalytics on mowers. I'm kind of surprised they aren't required now.

Of course, you know the 2 cycle engine has been killed for EPA regs. I really hate that. I love my older LawnBoy.

**clovis** · #23 03/13/10, 04:08 PM

Quote:

Originally Posted by Beeman

Exhaust gas recirculation was done to remove oxides of nitrogen by intorducing an inert gas(exhaust) into the fuel/air mix. Many vehicles no longer use exhaust gas recirculation. Fuel injection can precisely meter the fuel from the feedback of the sensors and the catalysts can do such a good job of cleaning all of it up.

Interesting info. I learned something new today!

HermitJohn · #24 03/14/10, 11:42 AM

Quote:

Originally Posted by clovis

Of course, you know the 2 cycle engine has been killed for EPA regs. I really hate that. I love my older LawnBoy.

I know some people love the old Lawn Boys, I've used them and worked on them, but didnt really see any advantage. I personally rather have OHV Honda or other Japanese 4 cycle engine with real choke and adjustable carb. Unfortunately I used to work on small engines for other people and know why they want to make them as owner-proof as possible. People do no maintenance, leave fuel over winter ect. And back when things were adjustable, people would play with the adjustments rather than properly curing the problem.

Probably same reason they made cars owner-proof and not adjustable.... I prefer personal responsibility and freedom, but see why things had to change. Too many people! And too many irresponsible people. Unfortunately rather than go high tech on cars, been better to stop subsidizing hiway system and subsidize private rail, thus making owning a private auto economically undesirable. Even with todays very low auto emissions, still the total cars out there pollute more than would a local commuter train system carrying same number people to work. Private passenger cars only really make sense for remaining low population rural areas.

Way back in 70s my mother bought a plug in electric lawn mower. Not that common back then. It was a hassle dealing with extension cords and I cut more than one by running over it when I would mow lawn for her, since I wasnt used to it, but otherwise the mower worked well with no maintenence other than occasional blade sharpening. Such mowers would eliminate homeowners pollution altogether and put it back on the power company. Guess I'd rather use an electric than deal with some really expensive high tech gasoline mower. Where I am now, out in the "rough", it would really be a hassle to deal with cords though. But for small urban/suburban yard, it would be way to go I suspect.