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Practical Standalone Tuning: Step 3: Base Table Configuation

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Step 3: Base Table Configuation

15.27

00:00 - The next step of our tuning process is to make some configuration changes to our base tables to set the break points, the load, and RPM break points to make sure that those are sensible.
00:11 We also want to get some numbers into those tables which are going to be a good starting point to actually get our engine up and running before we start making tuning changes.
00:19 At the same time while we're at it, we're also going to be setting up some safety parameters such as an RPM limit and a boost pressure limit just to ensure that if something goes wrong while we are starting out with our tuning, that the engine is less likely to be damaged.
00:33 Now in the Syvecs ECU we will also be making use of the closed loop fuel control to help speed up the process of tuning our fuel tables.
00:44 So we'll go through that as well.
00:45 Now it is important to understand as well with the Syvecs ECU, this is an injection time based ECU.
00:52 So our fuel maps are directly requesting a specific fuel delivery amount.
00:58 So this is quite an important aspect to take into account with our fuel tuning and also the calibration of our fuel tables.
01:07 Let's start by jumping into our SCal software, and we can access our fuel and ignition tables by going to our run mode fuelling or run mode ignition.
01:16 We'll start by looking at our run mode fuelling.
01:19 And at the top here we can see we have four base injection time tables.
01:25 So essentially the Syvecs ECU includes four maps.
01:29 These can be adjusted or selected using a calibration switch which can be wired into the ECU.
01:35 For our worked example here we are going to be focusing all of our efforts on our base injection time one table.
01:42 When we hover over that we can see we get a preview of that table on the right hand side.
01:47 And if we click on this or press enter, the table value come up.
01:51 We see the table is represented both graphically and numerically.
01:55 Now straight away a point with this particular engine is because it is direct injected, the values that we see in our fuel table here, the millisecond pulse widths being delivered to the injectors, would look a lot smaller than what we could expect to see on a port injected engine.
02:11 This is simply because of the reduced timeframe that we can inject fuel into a direct injected engine, we really only have the ability to inject fuel during the intake stroke and some portion of the compression stroke.
02:26 So this is why these numbers look small.
02:27 Doesn't really matter, the process of actually tuning the fuel delivery is still going to be exactly the same.
02:34 OK so now that we've understood the run mode fuelling, if we look at our run mode ignition timing, we can see we've got exactly the same setup here with four base tables and again we will be making our tuning changes here with our worked example on base ignition table one.
02:50 Before we get into actually setting some numbers into those tables though, we want to set up our axis break points, so let's go through that process now.
02:59 Let's move down to our break points and thresholds menu.
03:02 And one of the first things we can adjust is the load source or our primary load source, in this case we are using manifold pressure.
03:10 If we were running individual throttle bodies, we could choose throttle position there.
03:15 Then what we want to look at is our run mode primary break points.
03:20 These are the ones that we're going to be using for our primary fuel and ignition.
03:23 And we have first of all the number of engine speed break points, so how many break points we're going to be using, in this case 21, and we also have our number of manifold pressure break points, in this case we're using 18.
03:37 Once we've set those, how many break points we actually want, we can move down and we have the actual settings for these so if we go into our engine speed break points, you can see that we've set these essentially every 500 RPM.
03:49 With the exception that we have added a few more break points just around the idle and the transition off idle.
03:56 It's also important to make sure that you add break points that just go a little bit beyond the RPM range that we're expecting to use.
04:04 Let's move back our and we'll have a look at our manifold absolute pressure break points.
04:08 Again remembering that these are expressed in millibar and in this case we've set most of these break points at 200 millibar.
04:15 The gaps accept, you can see here we've got a load point at 100 and then a load point at 200 millibar right down at the bottom of the scale.
04:25 OK once we've got our break points set up, we can go back and we can have a look at our actual tables.
04:32 Let's move up and we'll deal with our fuelling first.
04:35 If we open our base injection time one table, we can see that we've got our load break points as we've just defined, and our RPM break points as well.
04:44 So at the moment we have got values in this table.
04:48 Now what we're going to do for the sake of getting started is just simply highlight that entire table, and we'll set the entire table here to a value of three milliseconds.
04:59 Now we don't need to think too much or too hard about this at the moment.
05:02 Remembering these numbers will be a little bit different to a port injected engine, so this is going to depend on your injector size as well.
05:08 But we don't need to be too fussy here, we're going to see in one of our following steps, just how easy it is to adjust these values if they aren't correct.
05:17 Now we've got some base numbers in that fuel table that we'll be able to get up and running with, we're going to move through and look at some of the corrections that need to be applied to that table.
05:27 If we go down to our corrections menu, what we're going to do is look first of all, at our simple manifold pressure multiplier.
05:36 Now what this does is works on the principle that if we double the manifold pressure, we need to double the amount of fuel being delivered into the engine.
05:45 So we can see here, if we look at our scale, that this is simply doubling the fuel delivery.
05:51 It's doubling the multiplier being applied as the inlet manifold pressure changes.
05:56 So for example at 1000 millibars we have a correction factor or multiplier or multiplier of 1.0 so no change is being made.
06:03 When we get out to 2000 millibars we have a multiplication factor of 2.0 and so on and so forth.
06:09 Now what this does is it just helps do some of the heavy lifting in the background of the ECU and means that we don't need to make such dramatic changes to the numbers in our actual base fuelling table.
06:21 Let's move back out now and we'll have a look at our air charge temperature multiplier table.
06:27 So this is simply a correction table for our inlet air temperature.
06:31 And we can see that we've got a two dimensional table here at the bottom with our inlet air temperature or air charge temperature on the x axis.
06:39 Now what I'm going to do here is just fill this table in and you'll remember from EFI tuning fundamentals, we recommend approximately 2.5% to 3% change in our fuel delivery for every 10 degrees centigrade.
06:55 What we're going to do is use our 20 degrees centigrade point here as the zero point in our table, so at this point we have a multiplier of 1.0 essentially this means no change is being made.
07:06 Let's just bring up our calculator here, and we'll use our calculator to figure out what our correction factors are going to be.
07:13 So for a start, let's look at the two extremes, or the left extreme I should say, of our table.
07:19 The value there for our air temperature is minus 10.
07:22 So this represents a 30 degree change from our 20 degree point, our zero point in our table.
07:30 So this means that we need to multiply our correction factor by three because we have three 10 degree increments here.
07:39 So if we take three, multiply this by 0.025 which is 2.5%, that's what I'm going to use in this case, we have a value of 0.075.
07:49 Now in this case remember when the temperature decreases, we need to increase the fuel delivery.
07:56 As the temperature decreases, the air density increases.
07:59 So what we want to do is set our minus 10 value here to a multiplier value of 1.075 I'm just going to directly enter that.
08:08 Now we need to go and do the same at our 110 degree increment there so 110 degrees, this is 90 degrees hotter than our 20 degree zero point, so this is nine increments of 2.5, in this case 0.025 and we want to actually reduce the number here.
08:30 So we'll add that as a negative.
08:32 That means that we need to reduce our fuelling by 0.225 If we express that as a multiplier this becomes 0.775 so we want to enter that at the extreme of our table.
08:48 Now if we simply highlight the entire table, we can use our math function here.
08:54 So this is up in the top menu.
08:56 Again I'm just going to use the hot keys here and press M.
08:59 And then what we want to do is some down to our interpolate function which I can access by pressing I.
09:04 And then we want to interpolate X, so we're interpolating in the X direction.
09:10 Press X and that gives us a straight line interpolation between those two extremes.
09:14 So that takes care of our air charge temperature table.
09:17 This should get us up and running.
09:19 Of course we can come back and adjust this if we find the need to later on.
09:23 Let's escape back out of that table and we'll move on and we're going to have a look at our air fuel ratio targets.
09:30 If we move down to our closed loop lambda selection here, this is where we can control the closed loop fuel control of the Syvecs ECU.
09:40 What we can see here is the overall enable we have set to bank1.
09:46 In this case with a four cylinder engine, the lambda sensor, all of the cylinders I should say, are assigned as being on bank1 so we're going to leave that as it is.
09:55 What we want to do now is come down to our lambda target.
09:58 So we can see just like our fuel and ignition, we have four base targets.
10:04 And we will be working on our base target one table.
10:07 Let's just double click on that and we can see our lambda targets here.
10:11 We've got exactly the same break points that we've already looked at for our fuel and ignition tables we can see.
10:16 And we've already gone and entered some sensible numbers in this table.
10:22 So I've gone quite conservative here, you can see that there's a large section of this table which is essentially set to lambda one in the cruise areas.
10:29 We're expecting our maximum load point to be around about 2000 millibar here.
10:34 And you can see that we've got our lambda target starting at 0.9 at low RPM, and as the RPM increases we are bringing those down to a richer target around about 0.82 lambda.
10:47 So this is gonna be a safe starting point, of course you're free to set your own desired lambda targets wherever you want them to be.
10:55 Let's escape out of that, so this is our lambda target table, we'll also just briefly have a look at a couple of the aspects of the closed loop lambda control.
11:03 In particular we do want to look at the maximum and minimum corrections which we can find down here.
11:11 So this limits the amount of control that that closed loop lambda system will have.
11:16 In this case we can see that our minimum final correction is minus 20%.
11:20 So the system will only be allowed to remove 20% fuel.
11:23 And likewise it will be allowed to add 20% fuel.
11:27 Now the Syvecs ECU does also give us the ability to adjust that correction when we are at full throttle.
11:35 So we start this with our correction limit full throttle threshold.
11:39 So this means essentially when we are past in this case 70% throttle, the Syvecs ECU will define that we are at full throttle and it will use the minimum and maximum corrections at full throttle instead of the ones we've just looked at.
11:55 Moving down we can see what these are, and you can see that we've allowed the ECU to remove 15% fuel or it can add 10%.
12:04 And again you can adjust these to suit your own personal preferences.
12:09 Because the ECU is running continuously in closed loop fuel control mode, if we want to target a richer air fuel ratio during cold start, we can do that by using our target adder table.
12:20 In this case the target adder table for engine coolant temperature or ECT.
12:25 Let's have a look at that table and you can see that until the engine reaches about 60 degrees centigrade, the lambda target is reduced slightly, hence targeting a richer air fuel ratio.
12:36 OK with our fuelling configured now, we're going to go through and have a look at our ignition timing.
12:43 So we'll close down our run mode fuelling.
12:45 And we'll have a look now at our run mode ignition.
12:48 Now our ignition table's set up with exactly the same break points.
12:53 We've already got some numbers in this table here.
12:55 What we're going to do is start by setting the off boost areas of this table up to 1000 millibars to 15 degrees of ignition advance, this is just a nice conservative value.
13:06 Likewise I'm going to set our 3400 millibar zone here to a value of five degrees.
13:14 And then what I'm going to do is simply highlight the entire table between 1000 and 3400 millibars and I'm going to use our math function, I'm going to hit I for interpolate, and this time I'm going to hit Y for interpolate vertically.
13:29 So this is just going to set us up with a table that should be nice and conservative to get us started with our tuning.
13:36 While I'm certainly expecting this engine to take more timing than what I've got in here, it's always safest to start with nice retarded numbers and be able to advance the timing up.
13:45 Of course regardless of the fact that we think we've got a conservative ignition timing map to start with, you always want to be using audio knock detection equipment in order to audibly listen to the engine and ensure that it isn't detonating while we begin our calibration process.
14:00 For the last step of our configuration process, we're going to set up a boost limit and a rev limit just to safeguard the engine while we begin our tuning.
14:07 We can access these through the limiters menu and we'll start with our manifold pressure limiter.
14:12 And we're going to set our pressure limit base1, this is the pressure limit or boost limit that the ECU will be using for our worked example.
14:22 In this case what I'm going to do is simply highlight the entire table and we'll set that to 2000 millibars.
14:28 So this will just protect us while we start getting up and running.
14:32 We'll close down our manifold pressure limiter and we can set either a rev cut or a rev limit depending how we want to control engine speed.
14:40 For this example we'll just use the rev cut function, and what we want to do is select an engine speed limit that we want to hold the maximum engine speed to.
14:51 In this case while we're getting started, it can be sensible to reduce the rev limit or rev cut down.
14:57 So for our initial tuning I'm going to set that to 5000 RPM.
15:02 It's important to remember this with both our boost limit and our rev limit, once we start increasing the boost and increasing the revs while we are tuning, we will often end up bumping into these artificially lowered limits that we've just set.
15:15 And we need to remember that so we can raise them, otherwise it can waste time during the tuning process.