WinOLS Mastery: Map Identification & Editing: Step 3: Understanding What Maps Are Required
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Step 3: Understanding What Maps Are Required
06.00
| 00:00 | The next step of our process is to get an understanding of what tables will be present in the controller that we want to define. |
| 00:07 | By understanding what tables are present and the logic flow that the ECU uses, this is obviously going to help drive what we're going to be looking for when we get to our map finding and map definition phase. |
| 00:20 | We have included a module in the body of the course that covers the EDC Bosch controller at a high level and the logic flow that it uses. |
| 00:29 | So, you can refer back to that for a more complete understanding of it. |
| 00:34 | However, we're going to cover off the key tables that we're going to be interested in here. |
| 00:39 | Remember as well that the tables that we're going to need to find and define will also be driven by how extensive the modifications to the calibration need to be. |
| 00:49 | As we've already discussed, this is a relatively straightforward stage one modification where we've got no hardware modifications to the engine at all. |
| 00:57 | So, this does limit the number of tables that we are going to need to define. |
| 01:03 | To start with, we begin with our driver's wish or driver's requested torque table. |
| 01:09 | And this simply takes the driver's accelerator pedal position into account and then outputs a requested torque value. |
| 01:18 | In the EDC controller, or specifically the EDC17, this is directly defined in newton metres. |
| 01:25 | So, it doesn't use the strategy that the Bosch gasoline controllers use where we're looking at a relative torque or a percentage of peak torque. |
| 01:35 | Once we've got our driver's requested torque, this is then transferred into a range of torque limitation tables. |
| 01:43 | So, this is an interesting element here, because we'll find that generally the peak torque value requested from the driver's wish table will then actually be dropped down or reduced by these limitation tables. |
| 01:57 | And in an interesting twist, a very simple and quick way of gaining more power and torque out of these engines is to simply raise the torque limitation tables to match the torque values in the driver's wish table. |
| 02:10 | Once we've gone through our driver's requested torque and torque limitation tables, we end up with a final torque request value. |
| 02:18 | This then needs to be converted into an injection quantity, so that the ECU knows how much fuel to inject into the engine. |
| 02:27 | And this is done with a set of tables referred to as NM conversion tables. |
| 02:32 | Simply, this takes the torque request and outputs a fuel mass in terms of milligrams per cycle. |
| 02:41 | We're not quite finished at this point though because the injection quantity or the final injection quantity can also be limited by our smoke limitation tables. |
| 02:51 | And as the name implies, this is just to ensure that our mixture doesn't become overly rich, resulting in visible smoke out of the exhaust. |
| 02:59 | Even in engines fitted with a DPF, while we may not end up necessarily seeing excess smoke out the exhaust, this will, if our air fuel ratio is too rich, end up clogging up that DPF prematurely. |
| 03:13 | So, we want to make sure that these tables are tuned sensibly and that we're not going to end up with an excessively rich mixture. |
| 03:22 | On top of our smoke limitation tables, there's also likely to be another set of tables that will cover limitation based on elements such as intake air temperature, engine coolant temperature, as well as oil temperature for both the engine and the gearbox, again, all really just limiting the injection quantity that is going to be finally delivered to the engine. |
| 03:42 | Once we've gone through all of these, we end up with our fuel mean amount or FMA value. |
| 03:47 | So, this is the amount of fuel that the ECU needs to deliver to the engine. |
| 03:52 | This value is then transferred into our start of injection table. |
| 03:57 | So, this is our injection timing when the fuel injection is actually going to be introduced into the engine. |
| 04:04 | At this point, we've essentially covered the fuel side of the ECU's operation. |
| 04:08 | The other side of the operation, of course, is our charge pressure. |
| 04:12 | And here we're going to have a range of charge pressure target tables, as well as charge pressure limitation tables. |
| 04:18 | There will, in an interesting twist, also in the EDC family of controllers, be a single value charge limitation parameter. |
| 04:26 | And this one is tricky to find. |
| 04:28 | We'll show you how to find and define that, though, as we move through this worked example. |
| 04:33 | But if you don't find this, it's going to essentially undo all of the hard work that you've done trying to raise the boost pressure with the other target and limitation tables. |
| 04:44 | We're also likely to find that there will be other charge pressure limitation tables based on compaction ratio, or even turbo speed based on the calculated turbo speed as opposed to the measured turbo speed. |
| 04:57 | Once we've got our final charge pressure target after going through all of those tables, this then gets fed into our VNT tables, which essentially sets our VNT position to achieve that target. |
| 05:10 | Now, again, depending on exactly how far we're intending to go with our torque requests or torque increase, as well as our boost pressure target increase, we may not need to modify the likes of our VNT target tables, just for an example. |
| 05:25 | So, at this stage, we've got a reasonably good understanding of that logic flow of the controller and those key tables that we're going to need to find. |
| 05:33 | At this point, I would also suggest that you write down those tables that you know now that you're going to need to find. |
| 05:40 | In this way, as we go through the map definition process, we can basically tick off each of those tables as we go. |
| 05:47 | This is going to make sure that we've defined everything that we're going to need when it comes time to actually tune this particular controller. |
| 05:54 | Let's move on now with the next step of our process. |
