The dirty cost of one man's hypermiling?

[dcb]

So you cannot properly ABA test this without getting your engine to stop without the ECU puking codes.

It looks to me like your ECU was delivering more fuel in the first test perhaps. The o2 is low and the co2/co is high. the cat would not be making more CO2 without being hot enough to do so. Fortunately that is a fairly easy thing to monitor at the injector

[SentraSE-R]

dcb, read the thread. My kill switch fixed the TCs long ago. Your ECU and TPS tangents ignore the elephant in the room, which is the unlit cat for the previous 800 miles.

I will ask the smog test station about the possibility of a retest, now that I have 900 recent cat-lit miles to clean the cat out. Hopefully they'll do it for less than their full price.

Back to the issue:
I'm reducing my fuel usage to 56% of normal. When the engine is running (let's assume 50% of the time, for a round figure), I'm spewing out 3-15X the average HCs, 3-7X the average NOx, and up to 6X the average CO at a minimum, when the cat is lit. So, if I cut my engine run time and gas usage ~50%, but quintuple my emissions during that time, I'm effectively emitting 2.5 times the pollution of the average car, when my cat is lit.

From my recent history, my cat isn't lit most of the time. If a lit cat is 50% efficient, my emissions through my unlit cat are double what they were during the smog test, when the cat was lit. If a lit cat is 90% efficient, my emissions through my unlit cat are ten times what they were during the smog test. That implies my P&G miles could be emitting 15-75X the average car's hydrocarbons, and 15-35X the average car's NOx!

I'm averaging 176% of the '08 EPA combined estimate. I can probably get 135-140% of EPA with engine on, cat lit, and normal emissions. That's sans P&G, and it's the direction I'm leaning now. Instead of 49.4 mpg, I'll get 39.2 mpg. Instead of using 55.7% of the average xB's fuel, I'll use 71.4%

[dcb]

ok, that is a large increase in fuel consumption with so little data to justify it. You are going to give BP and friends %25 more mula?

"common" causes:
Failed Emissions Test. My car failed the emissions test - SmogTips.com.

good 14 pages of how it works:
http://www.autoshop101.com/forms/h56.pdf

[SentraSE-R]

More data collected today. I drove 16 miles to a meeting, keeping the cat lit. It's a route I'd routinely get 55-60 mpg on. I got 38 mpg going out, and 43 mpg coming back.

I stopped at the smog test station coming into town. They wanted $50 to do a complete test with printout, but did a manual test for me for $20, with my car on the dyno rollers. See photos. My 900 mile drive to SoCal cleaned the cat. HC levels dropped below average for the most part. There's not much else that can be gathered from the data, since I don't know what rpms the car was running, what gear it was in, etc.

[user removed]

When I had my Echo (basically same engine) I regularly got 45-50 MPG with engine on coasting. When I ran through one tank using engine off coasting I got 57 MPG. Maybe you should just try engine on coasting and see how that does for keeping your cat lit. If my percentages are close to yours then your mileage hit would not be so hard. Of course the Echo was much lighter than the XB by a few hundred pounds, with better aero.

Saw a green XB today riding my gross polluter Vulcan 500 to have lunch with my buddy. Thought about yours. Old style carbs and no cat or feedback system on the Vulcan, compared to the CBR it's a relic but loads of fun.

Sentra, when I was 23 years old I had a 67 383 Formula S Barracuda. I was single and making good money, enough to max out my Social Security that year. For 16 weeks driving that 10 MPG gas hog. I burned through 100 gallons of fuel a week! 33 bucks in gas a week, making 13.5 grand a year, it was no big deal and I didn't know any better, but it sure was fun.

These days I would have to ride the CBR to the west coast and back, and back to the west coast every week, to burn through 100 gallons of gas. 100 gallons of gas would last me close to 8000 miles on the CBR.

We've come a long way in close to 40 years. I read somewhere that the exhaust coming out of a car is cleaner than the air going in since 2007. I doubt that seriously but I can remember what the air around here smelled like when I was a kid.

regards
Mech

[roosterk0031]

Good to hear the cars fine, lets see what some engine on P&G will do. I'm curious, but no way to find out, if at +90% load how well does the CAT work. Within the normal range that the engineers work it good, EOC P&G it doesn't, I doubt if they envisioned +90% load for 8 seconds, idle for 15 repeat.... The problem is without Engine Off P&G, is P&G worth the effort vs constant speed of you car in 5th gear.

I respect you care for the air over the almightly dollar. Makes me feel guilty my cars have never been checked. I'm curious enough now that I might get one or 2 of them tested come warmer weather. Wonder how a 250,000 gm v6 or 230,000 dodge I4 would test.

[user removed]

If your car is OBD2 then the cat function is tested by the second O2 sensor which is there only to activate the CEL when it detects poor cat function.
I thinks cats are still covered by 8-80 emissions warranty which does not apply in your case, but does in Sentra's.

regards
Mech

[dcb]

Originally Posted by SentraSE-R

... My 900 mile drive to SoCal cleaned the cat.

You keep asserting that, but it hasn't been substantiated.
Here, since you dropped $20, I'll put the data in a table to make it easier. It would be better with more tests and control tests, but this is it for now.

Test	RPM	%CO2	%O2	%HC	%CO	%NO	mph	hp	torque
1	1735	14.8	0.0	62	0.06	101
1	2800	14.6	0.3	16	0.02	89
2	1698	11.8	4.4	39	0.02	105
2	2752	11.4	4.9	14	0.01	74
3		11.7	4.5	2	0.0	75	6.1	5.3	117.4
3		12.1	3.8	6	0.0	544	7.8	6.7	116
3		12.1	4.2	11	0.1	195	9.8	8.6	117.5
3		12.3	3.4	3	0.0	76	14.6	12.8	117.3
3		12.5	3.1	1	0.0	71	14.9	13.0	117.3
3		12.2	3.3	1	0.0	90	20.6	10.9	70.9
3		12.3	3.5	0	0.0	78	25.0	13.1	70.2

Observations.
1. todays tests don't look like they have enough resolution for %CO
2. I don't know what scaling they use for %HC in test 3 but it varies a lot percentage wise. Is it apples to apples with the previous HC measurements even?!?
3. The readings at 117 ft/lbs are probably 1st gear
4. The readings at 70ish ft/lbs are probably second gear?
5. what happened to NO% at 7.8 mph?!?
6. CO2 has settled on a value between the 1st test and the second?
7. %O2 has also settled on a value between the 1st and second test?

What is the theory on the cat? Gasoline is pretty volatile, I don't know why you think it takes 800 miles to "clean" it, or why C02 is higher than test 2?

[SentraSE-R]

It's been a long time since I did NICE-on P&G, but IIRC, I got mid-40s mpg averaging ~30 mph. I got mid-50s mpg @32 mph in 5th gear cruise control on the same drive.

Are the data there to support an assumption that my engine is an average polluter when run normally (smog test 3)?

Are there any alternate theories with equal likelihood to dethrone P&G from being the cause of the above-average air pollution test results? I realize 4 months of relative inactivity, or one month of complete inactivity alone could be the cause, but given my P&G history, and the return to normal HC results after my 900 mile "normal" driving, is there another theory with equal likelihood?

Does anyone see any major logic flaw in my suspicion that I'm dumping 15-75X the average xB's HC into the air with unlit cat P&G? FWIW, my constantly-lit-cat drive today saw the cat temps staying between 985 and 1339 degrees F.

Mech, I was driving 100 miles/night looking for rattlesnakes in the desert when I was that age. Gas was 18.9 cents/gallon. Life was good. When I was younger, midday LA smog looked like nighttime Central Valley Tule Fog. We'd play touch football in air so foul, it gave us shortness of breath. I don't want my gaming behavior to swing us back in that direction.

dcb, I wish I could make more sense out of those data. The NOx spike seems strange. I'm happy to see the HC back to normal.

I P&Ged, I failed to light the cat, and my emission values were abnormally high.

I lit the cat for 100 miles, my emission values dropped, and were still abnormally high.

I lit the cat for 900 miles, my emission values returned to normal. Is there any other cause and effect relationship going on here?

[mechman600]

Catalytic converters don't get dirty and require "self cleaning" of any sort, your
900 miles of driving has little to do with anything other than getting somewhere far away. When the cat is cold, the nastiness that leaves the engine just flows on through out the tail pipe without turning into "friendly" things. Above ~500F when the cat is "lit", the nastiness the catalyzed into nice things like CO2 and H2O.