Efficient sure, but are we polluting less?
 

I understand that my EOC jags mean that my car is emitting less toxic gas across a given mile, on average. But I am curious about the emmisions while my car is ON. Have you wondered about this? When I bump start the rev spin up briefly a few hundred RPMs sometimes. I have advanced ignition timing 2* and have installed a WAI. When the engine is on, I wonder how I am doing relative to ordinary stock. Knowing at least hypothetically would help me estimate my total output relative to pre-ecomodding days. Anyone thought this through yet?

I'd be willing to be (a whole shiny nickel!!) that we do pollute more just after a bump-start than someone does during steady-state cruising. I'd be surprised if it were more during a P&G cycle (or better yet, a long stop light!) than would be emitted during that whole steady-state cruise, or idling at the light.

The exhaust of my CRX gets black quickly. I attribute that to running slightly rich after bump-starts.

Get your scanguage to show when your in open/closed loop. See how long it takes after bump start to go back into closed loop. If we "ass-u-me" that open loop produces 4 times as much polution as closed loop and it takes 5 seconds to go back into closed loop then we need to be shut off for more then 20 seconds to produce less pollution. That's why the "rule-of-thumb" don't shut engine off at light if it will only be off for less then 10 seconds.

The one I violate all the time is going for a drive to hypermile to get this tank average up when I don't really need to go anywhere. I.E. bad day to/from work only got 42mpg so I go for a 50mile round trip to get some dinner that averages 60mpg to bring days average back above 50mpg.

One of the forum members has recently been using a gas analyser to see what comes out of the tailpipe when using P&G.

It was considerably more than using steady state driving.

Got a link to that?

I'll repeat Daox request for the link. I remember that post but not well. *If* I remember correctly, there were two problems with the rushed test he did: (1) he did not get the best readings by his own description and more importantly (2) he was key starting the vehicle, not bump-starting, which would have produced lower emissions.

Nonetheless, I'm confident that if I bump-start, pulse for a few seconds, and glide for most of a minute... the car has on average emitted less pollution than steady state. But I realize my confidence is not proof. Anyone have the equipment?

Here you go :

http://ecomodder.com/forum/showthrea...ute-14571.html

And more recently, starting here (links to the relevant message):
http://ecomodder.com/forum/showthrea...tml#post257453

And that's bump starting it.

On my Civic it goes into Closed Loop immediately. It's within one refresh cycle on the Scangauge.

I'd have to agree with hackish, he needs more vehicles to do testing on. His car is almost 20 years old. There have been tons of innovations since then and a lot of them have to do with emissions. My Paseo which is a 97 also goes into closed loop almost immediately after bump starting. That ensures that the engine is burning cleanly, but it doesn't make sure that the CAT is up to temp and doing its thing. Unless he does testing on more modern vehicles, I couldn't make a decision one way or the other.

Thanks much for the link. What did you think? I thought his analysis was all wet, as several pointed out. The best is when he finally comes back into the discussion and argues for an "engineer's" theoretical analysis--utterly wrong as to BSFC maps--and uses it against ABA data for the effectiveness of the P&G technique. I'm sure there are more of these, but I tested P&G with engine on versus steady state at identical speeds on the freeway and found a very significant FE benefit for P&G. Here's the link. But on his original posting about pollution, his car was atypical, a lean burn VX, and his methods were not great while his data was never reported to the forum. Not at all persuasive, seems to me.