Emissions Tuning Fundamentals: Tip-In Enrichment Demo

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Tip-In Enrichment Demo

06.28

00:00	When it comes to tip and enrichment, we want just enough to make the vehicle drive really smooth, but without having too much and causing excess hydrocarbons or other emissions.
00:09	We also want to be cautious to avoid having too little tip and enrichment, which can cause a stumble or a spike in NOx.
00:16	So, for this demonstration, I've taken our stock file that we've run the 505 on earlier, and we're gonna run another hot 505 with some extra tip and enrichment and see how the data compares.
00:28	We've got our data logging started, drive trace coming up.
01:01	Now, during this hot 505 test, for the most part you're trying to be smooth as a driver, so you shouldn't be creating too many tip and enrichment events, but there certainly are some shift events where you're upshifting, and that'll be where we'll most likely see tip and enrichment coming into play.
01:29	In addition, some of the acceleration events are a little more aggressive than others, and if they're aggressive enough, then we might get some tip and enrichment there as well.
02:00	Up in the sixth gear, here we're at pretty steady state, so no tip and enrichments here, and I'm just going to try to keep us on the trace to keep those other areas of this test consistent with the prior one.
02:15	Consistency from test to test is always tricky, because the driver does play a critical role in the emissions results.
02:22	So, you just do your best, and then of course when it comes time for certification, the pros will be in the car driving and you won't have to worry about it.
02:38	If you're doing your testing at SEMA Garage, their drivers are excellent.
02:43	At some other labs I've had mixed results, so that's another thing to keep in mind.
02:48	In addition to the facility itself and the quality of the equipment, the quality of the staff can play a major role in the emissions results.
03:06	All right, we're coming up to some downshifts.
03:35	All right, and that concludes our test, so I'll just have to check the results out and see what this tip and enrichment change did for us.
03:42	In our tip and fueling test, I made a huge increase in tip and fuel to see how that transient behavior changes.
03:48	Right now I've pulled up our hot 505 results from a standard test on the factory calibration.
03:54	Up here up top, we have got our vehicle speed.
03:57	Next, row is NOx, then hydrocarbons in red, carbon monoxide in green, and CO2 in yellow.
04:05	And you can see right here, most of our emissions occur at the very beginning of the test after our restart.
04:12	Now,, the vehicle was relatively warm here, but the catalyst wasn't that hot, so that's why we're seeing pretty significant emissions right at the start of the test.
04:24	I'm going to pull this up and compare to our tip and extra fuel test.
04:32	And you can see the data is being overlaid there.
04:36	I'm just going to tweak how it's overlaid slightly to get these to line up perfectly.
04:40	So, in this particular test, one thing I see here is we have a large spike in NOx on the baseline result, which seems to be present during this acceleration area here.
04:54	So, the spike starts at about 36, 37 seconds there.
05:00	So, if we go back to 30 seconds, yeah, it's part of our acceleration.
05:07	And then as we tip out and tip back in here, that seems to have occurred.
05:12	Now, if we go down and look at hydrocarbons, we see a bit of a spike there.
05:19	But if we look at our tip and enrichment increased file, we have a huge spike that goes so far it goes off the screen.
05:28	And what we also see here is this NOx area is quite a bit lower.
05:33	In this case, we're looking at about a peak of 45 versus a peak of somewhere around 9.
05:40	So, the additional enrichment here actually got rid of the spike of NOx, and provided additional hydrocarbons instead.
05:48	So, one thing you'll notice is those are often at odds with each other.
05:53	So, as we add additional enrichment, we're typically going to see increased hydrocarbons reduce NOx.
05:59	And here we had an area where we were likely slightly lean of lambda 1 on the baseline run in that particular area.
06:05	And we've cleaned that up with that additional tip-in fueling.
06:09	But we've likely overdone it and now caused hydrocarbons to spike.
06:14	So, always a delicate balancing act, and that's why we have to be very precise in our emissions calibrations, which take it to a level beyond typical tuning just for drivability.