Emissions Tuning Fundamentals: Cold 505
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Cold 505
05.11
| 00:00 | So I'm about to start a cold 505 test, which is part of the FTP75 drive cycle. |
| 00:05 | And in order to do this, we're going to be gathering modal data, and we've decided on a flow rate of 20 CFM. |
| 00:11 | This is going to allow us to see some peaks, and just in case we have significant overfueling or any issues on startup or anything of that nature, the data won't get clipped as we're looking at it real time. |
| 00:23 | So I'm going to get ready to start the drive trace and the engine, and then we'll get going. |
| 00:43 | All right, we got the vehicle started. |
| 00:47 | We're coming up to the first portion where we get the vehicle rolling. |
| 00:52 | And as you can see, it indicates which gear we need to be in. |
| 01:24 | So I'm following the trace up and down, staying in second gear. |
| 01:45 | And here we have to actually use the brake. |
| 01:52 | De-clutch... |
| 01:54 | And we're stopped. |
| 02:09 | Now we're getting up to a higher speed section of this test, up around 55 miles per hour. |
| 02:16 | And that'll just give the analyzers a chance to see how the engine's doing in this operating range. |
| 02:31 | The crosshairs on the grid allows me to keep it best aligned with the drive trace. |
| 02:37 | Here you can see I need to drop down, then the crosshair shifts when I need to speed up. |
| 02:43 | I'm a bit under pace. |
| 02:52 | It's relatively easy to stay on a trace when it's more stable like this. |
| 02:57 | The more aggressive acceleration and deceleration areas definitely take some practice. |
| 03:03 | And the folks at the lab have done it so much that they do a fantastic job of it, but this is something that you can practice at home on your dyno. |
| 03:12 | And become much better at. |
| 03:18 | All right, we have some downshifts coming up. |
| 03:31 | So as we're looking at the results, remember that there's about a seven second delay between my inputs and what the engine is doing, and the real-time results we're seeing on the screen. |
| 03:54 | So right now NOx at 0.04 parts per million. |
| 03:59 | As we get into a decel operation here, see if we get any spikes there. |
| 04:14 | Nothing I can see here. |
| 04:16 | Everything looks pretty carefully controlled. |
| 04:19 | Hydrocarbon stable as well. |
| 04:21 | And that's the finish of our test. |
| 04:23 | The real-time emissions data recorded throughout the test can be correlated to my Cobb data log via the vehicle speed monitor. |
| 04:30 | Both the dyno know roller speed and the ECU knows vehicle speed, so I can correlate the two based on where the test starts and when I get going from zero miles an hour, get up to speed, and that'll keep things lined up during the test. |
| 04:44 | Again, just remember we do have that approximate seven second delay between emissions being registered and what the vehicle was doing. |
| 04:52 | With that in mind, there's a few different ways you can handle this. |
| 04:55 | You can offset the data from the dyno and the engine computer by seven seconds. |
| 05:01 | And oftentimes this may look a little odd since the vehicle speed traces will not line up, but can give you the best results. |
