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Launch Control: Input Configuration

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Input Configuration

13.14

00:00 - Now that we've got an idea of the menus that we are going to be adjusting, we're going to go through and look at the actual setup.
00:06 The first part of that is configuring the inputs to the ECU, and as I said in the last module, we're a little bit ahead of the game here because all our wheel speed sensors are coming in via CAN.
00:19 However, I will show you how you could configure a digital input as a wheel speed sensor, if that's the way you are getting your data.
00:27 If we go into the ECU Settings menu, we can choose our digital inputs, and we've got a list of all the digital inputs available.
00:39 I'm just going to set up digital input two here and we'll have a look at that.
00:43 Let's say we wanted to set this up as a left-front wheel speed sensor.
00:49 We can choose left front wheel speed.
00:52 If you wanted to, you could enter a label for this particular sensor, however, it will read LF wheel speed anyway, which is pretty straight forward.
01:02 The options we've got here, we can turn on a pull-up resistor.
01:06 If we're using a Hall-style sensor, you're going to need that pull-up turned on so that the ECU can differentiate between the high and low states as the speed sensor goes past the pick-up.
01:18 So we would turn that on.
01:21 We can choose the Active Edge, which is going to depend on the sensor setup you're using.
01:27 And finally, we have the Calibration Value, which is dependent on the number of pick-ups you're using on the wheel, as well as the rolling diameter of the wheel and tire combination.
01:40 As I said in the body of the course, the best place to set up the wheel speed calibration is on the Dyno, where it's nice and easy.
01:48 However, for this particular car, as I said, we're getting our wheel speed data via CAN so we don't need to look at that any further.
01:57 The other thing we will need to do, however, is we will need to set up a clutch switch, which is how we're activating our launch control.
02:05 If I open up the Digital Inputs again, you can see I've got DI 6, Digital Input 6 set up as a clutch switch.
02:12 So this is wired up to a switch at the base of the clutch pedal's travel, and you can see, again, I've got it set up and called it Clutch Switch, so there's no real need to add a secondary label to that.
02:25 We don't need the Pullup Resistor turned on for this particular input, and that's really going to depend on what the clutch switch is inputting to the ECU.
02:35 If we're switching to ground, then we're going to need the Pullup Resistor turned on so, again, the ECU can differentiate between when the clutch switch is on and when it's floating.
02:47 In this particular case, our On Level is High so when there is a positive voltage to the ECU, which is, again, why we don't need that Pull-up Resistor turned on, and we're activating on the rising edge of that signal.
03:02 Once I've got that configured, we can test and make sure it's working.
03:06 If we press R or F12 to bring up the Runtime Value screen and we click on the little Digital tab here, we have a list of all of our Digital Inputs.
03:15 And you can see DI 6, Digital Input 6 is shown here as a Clutch Switch.
03:20 As I put my foot on and off the clutch, you can see that the Clutch Switch goes from Off to Active, so we can tell that that's working.
03:29 We can also use this to test and see where, exactly, on the clutch pedal's travel it is engaging.
03:35 That's really convenient for doing a quick test of that.
03:40 The other thing we're going to do now, is I'll just start the car, and we'll test and make sure that we're getting a valid input from our wheel speed sensors.
03:50 You can do this regardless of whether you're getting them directly from a digital sensor or, in our case, via CAN.
03:57 If I click on the CAN tab, we can see nothing.
04:03 Great.
04:08 Hold on, I'll just fix that.
04:13 So if I move through and we click on the Miscellaneous tab up the top, you can see that we have our wheel speed sensors coming in here on the right-hand side via CAN.
04:24 What I'll do is I'll just drive along and make sure that we are registering wheel speeds from all four wheels.
04:31 You can see as I drive along, the wheel speed increases, so we know that that input is valid.
04:37 Again, because this is a pre-configured setup that's coming in via CAN, I also know that the calibration of those inputs is accurate.
04:46 That takes care of the input setup.
04:48 We know that that's all configured correctly, and we want to do that before we get into actually tuning the Launch Control System because, otherwise, we're going to be potentially chasing problems with clutch switches that aren't functioning or wheel speed sensors that aren't calibrated correctly.
05:05 The next place we want to go is we want to have a look at our actual Launch Control menu, and remember, that's found under the MotorSports subheading.
05:15 If we click on Launch Control, we've got all of our available options.
05:20 In the next module, we'll actually look at the tuning, but for this section, we're just going to have a quick look through the options available to us.
05:29 We start with our Launch Control Mode, and we've got the ability to set this up in a few different ways.
05:36 The simplest is our Single Launch RPM, which we'll look at first, which would be our two-step style of Launch Control.
05:44 We can also have a 2D Launch RPM Table, which is what we'd use for our ground speed-based Launch Control.
05:52 We could set that up, also, as a 3D Launch Control RPM Table, which is ground speed-based, but we have another access we could use if we want multi-positions for our Launch Control, so if we want, perhaps, a switch to give us a dry and a wet setting, we would use that.
06:10 Then we finally got a Latched Launch RPM mode, which is a function that Link have included for roll racing where you can latch your Launch Control while you're actually driving using a switch, so you can actually launch while you are moving.
06:26 We won't be looking at that in this car, so we'll just look at the more simple setup.
06:33 We'll leave that at the moment at Single Launch RPM.
06:37 Next, we've got our Activation Control, so what is actually going to be switching the Launch Control functionality on and off.
06:44 We can choose from any of our digital inputs in here, and we've chosen DI 6, which is what's connected to our Clutch Switch.
06:54 We've got an Arming Time.
06:56 What this means is that the Clutch Switch needs to be active, or our Activation Control needs to be active for the Arming Time before the ECU will go into Launch Mode.
07:09 We can, if we wish, use a Fuel Trim Table.
07:12 You can turn that on or off depending on whether or not you want to use it.
07:16 And, again, because we're using our Single Launch RPM mode here, this is a very simple system, we've got our Launch RPM configured here.
07:25 At the moment, you can see I've got that set to 2,000 RPM.
07:29 The other thing we can do with all of the Launch Control systems in the G4 plus and ViPEC, is control the ignition timing, retard the ignition timing, if we wish to help build boost.
07:41 Obviously, at the moment, we're using a naturally aspirated car, so there's not a lot we can do to build any boost, but I will, in the next module, talk about how we can use that if you are running a turbo-charged car.
07:56 We can choose to have a Single Zone or a Table for our Ignition Retard.
08:01 We can retard the timing, the numbers we can enter there, we can enter as a number of degrees, which is removed from the base Ignition Table.
08:15 We can remove a percentage or we can retard in Degrees Absolute.
08:20 So if we're choosing Degrees Absolute, that will be the number of degrees after TDC, so if we enter 10 degrees, for example, that will retard the timing to 10 degrees after TDC.
08:32 To stop the Ignition Retard killing the engine and making it very slow to respond, we can bring that Retard in above a certain throttle position which is sensible.
08:42 In this case, we've got that at 60%.
08:44 So that allows the car to respond normally when we first engage Launch Control, and the Ignition Retard won't become active until we actually go to full throttle.
08:54 At the same time, you could also make that retard active above a certain RPM.
08:59 Again, we'll look at that in the next module in a little more detail.
09:02 Then we finally have our actual Launch Trim.
09:07 The next thing we're going to look at is Launch Limiting.
09:11 This is the type of Limiter that the ECU is using to control the engine RPM.
09:19 We have three options here, well, four, you can turn it off if you wish.
09:23 We have Ignition Cut, which as you know from the body of the course, is my preference.
09:29 We can choose Fuel Cut, or the Link in ViPEC ECUs also include a Rotary Only mode.
09:35 This is a combination of a fuel and ignition cut, which is designed to minimize the popping and banging which is potentially quite destructive to a rotary engine.
09:47 We've also got the option of an Advanced Mode which we can turn on or off.
09:53 The Advanced Mode gives us access to a lot more control around the way the limiter works.
10:00 For most applications, it won't be necessary.
10:03 You won't need to look at that, and the standard limiting will do a perfectly adequate job of controlling the Launch RPM.
10:13 You can see, if we turn that off, we've got no more access to any more menu options there.
10:20 I'll just quickly talk through the options that are here though.
10:24 If we do turn that on, we've got the ability to control the Rev Limit Range.
10:31 We can control the type of Cut Effect, so we've got the option here of an Adaptive or a Constant RPM cut.
10:39 The Constant RPM cut applies a consistent cutting pattern, so it'll cut the same cylinders time after time, which can result in the cylinders that are being cut potentially fouling.
10:53 The Adaptive cut, which would be my suggestion here, applies a randomizer to the ignition or fuel cutting, and that means that we never have the same cylinders cutting repeatedly.
11:07 If you wish to use a Hard Limit, you can turn that on, and we also have an Activation RPM of how far above the control range the RPM needs to reach before the Hard Limit will become active.
11:19 We've got a Start Cut when our throttle position is low.
11:22 So when the throttle position is below the low threshold here, which we can adjust, this is the percentage of cut that will immediately be applied.
11:36 Likewise, when the throttle position reaches 100%, this is the amount of cut that will be applied.
11:44 What we can do, essentially, the idea behind this, is we're trying to control the amount or percentage of cut being applied relative to the amount of engine power.
11:55 Obviously, when we're at a very light throttle setting and we just come up on the rev limit, the engine isn't making much power so we don't need a huge amount of cut to control the rev limit.
12:05 On the other hand, if we hit the rev limit at wide-open throttle and the engine's making a lot more power, we need to apply a larger percentage of cut to help control that engine speed.
12:16 So we can adjust these parameters to achieve that.
12:20 Finally, we've got an Exit Decay Rate.
12:22 This is how the ECU will respond once the limit is deactivated, so once we leave the launch control function, once the clutch switch is disabled.
12:35 This defines how quickly the cut is being removed and its percentage being removed for every 20 milliseconds.
12:44 A larger number here will reinstate engine power more aggressively, whereas a lower number will take longer to reinstate the engine power.
12:54 And this can be tuned to adjust the feel of how the ECU responds coming off the Launch Control function.
13:00 Ok, now we've got an overview of the inputs and the configuration, and we've got all of that set up.