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MoTeC M1 Software Tutorial: DBW Throttle

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DBW Throttle


00:00 The M1 ECU has the ability to control up to two drive by wire throttle bodies and in this module we will look at how to properly configure and test this system.
00:10 Drive by wire throttle control is critical to the safety of your vehicle and for that reason these settings need to be approached with care.
00:18 In particular incorrect PID settings may result in erratic or unexpected throttle operation.
00:25 It is important to start by contacting MoTeC or your local MoTeC dealer to get the correct settings for your particular throttle body - Setup sheets are based on the factory part number of the throttle body.
00:38 If you have a throttle body that data is not available for, you can send your throttle body to MoTeC through your local dealer to have it properly characterised.
00:47 For safety, its is important not to try creating custom throttle setups, such as multi throttle bodies with a drive by wire motor bolted to the side of it.
00:56 There are a lot of things the car manufacturers must consider when creating a successful drive by wire throttle arrangement that may not initially be apparent.
01:05 If you have specific drive by wire throttle requirements that are not met by a factory system please contact your MoTeC dealer to discuss options before spending time and money.
01:16 MoTeC will not calibrate any drive by wire throttle systems that are not considered to be safe.
01:23 Now we can move into the throttle configuration.
01:27 The drive by wire throttle control is defined by the ‘Throttle Pedal’, ‘Throttle Aim’ and ‘Throttle Servo’ worksheets.
01:34 We will start with the ‘Throttle Pedal’ worksheet which defines the input from the driver’s throttle pedal.
01:41 The configuration of the throttle pedal for drive by wire operation is similar to what we have already looked at for a conventional cable throttle only this time we have dual position sensors known as Main and Tracking.
01:54 The two sensors are used to check each other so the ECU can be doubly sure of the pedal position.
02:00 We can start by assigning a Voltage Resource and Voltage Reference to the ‘Throttle Pedal Sensor Main’, and then do the same for the ‘Throttle Pedal Sensor Tracking’.
02:10 The Voltage Reference is quite important for high accuracy and is simply the five volt output that is used for the two sensors.
02:19 Now with the throttle pedal in the closed position, click on the ‘Throttle Pedal Main Offset’ parameter and press the ‘Q’ key to calibrate it.
02:27 Make sure that the ‘Throttle Position Tracking Limit’ is set to one hundred percent unless specified differently in your particular data sheet.
02:35 Press the throttle pedal all the way to the floor, click on the ‘Throttle Position Main Scale’ and press ‘Q’ to calibrate it.
02:43 Calibrating the Main sensor will also calibrate the Tracking sensor.
02:49 During calibration, make sure the pedal is pressed all the way to full travel using your foot.
02:55 Occasionally tuners will use their hands to perform the calibration, and the pedal may end up having its travel restricted by the carpet or a floor mat for example.
03:05 When the car is being driven though and the driver wants to go faster, they will try to push the pedal through the firewall, which may move the pedal further than what it was moved during the calibration.
03:16 Make sure you account for this in your pedal settings by setting them in the same manner.
03:22 You should now be able to move the throttle through its travel and the ‘Throttle Pedal’ channel should move smoothly from zero to one hundred percent.
03:30 It is advisable to check the Throttle Pedal Sensor Diagnostic channel while checking the pedal operation to make sure it stays as “OK”.
03:39 You may also need to adjust the diagnostic high and low values (outside of this range the throttle position sensor is considered to be in fault) for both the Main and Tracking inputs to make sure they fall outside the normal voltage range during operation but generally the default values should be fine.
03:53 Before we move on, you can see that we have a parameter called ‘Throttle Pedal Translation’, and we can use this table to alter the relationship between pedal position and throttle plate opening, again, clicking on the table and pressing “A” will allow the tuner to adjust the table sites if desired.
04:11 This can be used to adjust the responsiveness or aggressiveness of the throttle, and there are two separate settings that can be selected using a switch if desired.
04:22 Next we can move along to the ‘Throttle Aim’ worksheet and there isn’t much we actually need to configure here.
04:28 We can start with the ‘Engine Crank Throttle Aim’ which is the throttle target the ECU will use during cranking if the closed loop drive by wire idle speed system is not being used.
04:39 This can be adjusted to achieve a good clean startup as well as a good transition to idle.
04:46 Next we have ‘Idle Actuator Throttle Aim Maximum’ which is a repeat of the same parameter we looked at in the section on idle speed control.
04:56 If we move down, we also have some throttle limits that we can choose to configure if desired.
05:02 We can control the throttle position based on the ‘Engine Load Average’ or ‘Race Time’ parameters and as usual if you wish to use either of these, you can configure a table to suit by pressing the ‘A’ key to enter the axis setup menu.
05:17 The last parameter in the list is the ‘Vehicle Speed Limit Throttle Limit’, which is the throttle limit that will be applied when the speed limit is active.
05:25 If you don’t want to use any of the throttle limits, set them to one hundred percent.
05:30 If these tables are used the throttle translation table will still apply but the throttle maximum position will not exceed the limit table that is in use.
05:39 This means pedal feel will not be affected.
05:42 Moving on, we have a channel here that we can use to monitor the current throttle limit source, which can be useful for identifying where a throttle limit is originating from.
05:52 Lastly we have an engine speed limit that will be applied if a fault is detected from the throttle servo control system.
05:59 This is a safety parameter used to prevent excessive engine speed in the event that the drive by wire throttle system fails for any reason.
06:08 That completes the ‘Throttle Aim’ worksheet, and the last worksheet we need to cover in this section is the ‘Throttle Servo’ worksheet.
06:15 You will notice that there is another worksheet labelled ‘Throttle Servo Bank 2’ which will need to be configured for engines running dual drive by wire throttles.
06:31 The settings mirror those found in the first worksheet so for our example we will just look at configuring a single throttle body.
06:33 There is a dedicated setup procedure to step through to configure the throttle servo correctly but first we will look at the ‘Servo Bank 1’ parameters.
06:43 First we have the ‘Throttle Area’ table which defines the ratio of effective throttle area between zero and one hundred percent.
06:51 We can choose to make use of this table to account for the non linear aspect of the airflow through the throttle body, or we can choose to use a linear translation for this particular table if accurate data isn’t available.
07:04 Be wary of changing this after systems like idle speed control are set though, as generally drive by wire functions are requesting a throttle area and the ECU uses this table to come up with the right throttle blade angle.
07:18 If you configure your drive by wire idle control and tune it changing this table will change the idle tuning.
07:25 The ‘Throttle Servo Dead Band’ is a range of throttle position above or below the target that is considered to be on target and hence the throttle servo will not be driven.
07:35 We want accurate control of a drive by wire throttle so by its nature, this dead band will be very small.
07:42 This is a parameter that is part of the MoTeC calibration document for the particular throttle body, so use the number supplied by MoTeC.
07:51 Next we have the ‘Throttle Servo Power Save Delay’ which defines the time period before the throttle servo will be disabled to save power.
07:59 This will also eliminate the characteristic buzzing that can often be heard from a drive by wire throttle servo.
08:06 A value of two seconds here is typical.
08:09 When the engine is off and the power save delay has timed out the throttle control will be turned off.
08:15 The throttle control will automatically be turned back on if there is any RPM or if the driver uses the pedal.
08:21 In the event of an error, as long as the throttle control is allowed to return to power save (engine off and the time elapsed) the ECU will assess the various sensors used in the system, if for example one pedal sensor has failed the ECU will allow the throttle system to work with just one pedal sensor.
08:37 If both pedal sensors have failed obviously there would be no way to request throttle.
08:42 The last parameter here is ‘Throttle Servo Bank 1 Mode’.
08:47 This enables or disables the throttle servo, but before we enable it, we need to go through the rest of the configuration process and we will do that now.
08:56 Start by ensuring that the ‘Throttle Servo Bank 1 Mode’ is in fact set to ‘Disabled’ Now we need to configure the ‘Throttle Servo Bank 1 Position Main Voltage Resource’ and ‘Reference’, the reference is simply which 5 volt pin you have wired the sensors to.
09:14 Next we need to complete the same steps for the ‘Throttle Servo Bank 1 Tracking Voltage Resource’ and ‘Reference’.
09:21 The ‘Position Main’ and ‘Tracking’ inputs give the M1 ECU two references to the throttle servo position which are required to make sure the throttle is performing properly.
09:31 Now we need to set ‘Throttle Servo Bank 1 Position Mode’ to ‘Enabled’ 6Next make sure that the ‘Throttle Position Bank 1 Tracking Limit’ is set to one hundred percent unless your particular data sheet specifies otherwise.
09:46 This parameter is used for some throttle servos where the tracking voltage only measures part of the throttle movement range (Ford BA/BF and some Toyota throttles).
09:58 Next you will need to physically hold the throttle butterfly by hand in the closed position, click on the ‘Throttle Servo Bank 1 Position Main Offset’ parameter and press the ‘Q’ key to lock in the closed throttle value.
10:12 Now physically hold the throttle butterfly in the fully open position and repeat the process for the ‘Main Scale’ parameter.
10:20 Don't hold the throttle butterfly against the fully open stop, reduce the throttle position by a few degrees, most throttle stops are at more than 90 degrees anyway.
10:32 Again, setting the Main parameters will automatically set the Tracking.
10:37 You will notice that diagnostic high and low values are provided for both the ‘Position Main’ and ‘Tracking’ inputs and these may need to be set to ensure that they are outside the normal operating range of both sensors, again default values are generally fine.
10:54 We can now enter an output resource for the ‘Throttle Servo Bank 1 Motor Output’ and enter the control and motor parameters from the setup sheet provided for your particular throttle.
11:05 Lastly you can now enable the ‘Throttle Position Bank 1 Mode’.
11:10 When changing resources the ECU will require a reset which will be indicated by a red highlight at the top of the screen.
11:17 Pressing “Ctrl” + “S” will start this process.
11:21 Now test the system to ensure smooth and accurate tracking between zero and one hundred percent occurs as you move the throttle pedal.
11:30 The Throttle Servo Diagnostic should stay as “OK” while testing the movement and go to “Power Save” when the engine off is off and the Power Save Delay time elapses.
11:41 We now should have both the throttle pedal and throttle servo correctly configured and calibrated with a properly functioning drive by wire throttle system.

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