MoTeC M1 Software Tutorial: Sensor Setup
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Sensor Setup
11.33
| 00:00 | For the M1 ECU to be able to do its job, it relies on the input from a wide range of sensors to tell it about the operational conditions of the engine such as inlet manifold temperature, manifold pressure and ambient air pressure. |
| 00:15 | o get the best results from the M1 ECU, correctly configuring the various sensors is important and in this module we will look at how to approach it. |
| 00:25 | At this point we are still in the ‘Initial Setup’ work book, and you can see that we actually have three worksheets that deal with sensors. |
| 00:33 | The ‘Sensors Critical’ worksheet deals with essential inputs that the ECU needs for the the fuel and ignition models to work properly. |
| 00:42 | An example of these sensors would be the inlet manifold pressure sensor and the engine coolant temperature sensor. |
| 00:50 | While we don’t necessarily need to fit all of the sensors in this worksheet to the engine, we do at least need to make sure that the default values for these sensors are set sensibly. |
| 01:02 | To highlight the importance of these sensors let’s discuss the intake manifold temperature sensor in a little more detail. |
| 01:10 | In the older hundred series ECU this sensor was simply an input to a fuel correction table that the tuner needed to calibrate themselves. |
| 01:20 | Generally this table wasn’t handled well and often was left untouched or incorrectly adjusted leading to variable results. |
| 01:29 | The density and hence mass of the intake air varies as a function of air temperature, and hence it is a critical aspect to the M1’s fuel model. |
| 01:39 | For this reason the M1 includes the output from the inlet manifold temperature sensor in the main fuel equation with no input from the tuner. |
| 01:50 | For the fuel model to work correctly, it is essential for the inlet manifold temperature to be accurately measured. |
| 01:58 | Next we have the ‘Sensors Optional’ worksheet which deals with optional sensors that aren’t essential, but will help the M1 do its job better. |
| 02:07 | An example here would be a fuel pressure sensor that will let the ECU constantly reference the actual differential fuel pressure across the injectors. |
| 02:18 | The last worksheet is the ‘Sensors Other’ worksheet which lists a range of possible sensors that can be included primarily for data logging and analysis reasons and aren’t strictly necessary for the correct operation of the ECU. |
| 02:33 | An example of this sort of sensor may be turbocharger speed or Exhaust Back Pressure. |
| 02:39 | We are going to start with the ‘Sensors Critical’ worksheet first. |
| 02:44 | Since these sensors are critical to the operation of the M1, we want to start by making sure the default values are set to a sensible value. |
| 02:53 | For example we aren’t probably going to have a fuel temperature sensor fitted to every engine, but fuel temperature is part of the M1’s fuel model so a valid value is necessary. |
| 03:05 | If the sensor isn’t fitted, this reading will come from the default value. |
| 03:10 | Likewise if a sensor goes into fault, the ECU will revert to the default value so it’s important to enter these correctly. |
| 03:19 | We can do this by typing default in the search box here and you will see that the default values for each sensor are listed. |
| 03:27 | You can then adjust these as necessary to suit your installation. |
| 03:32 | Most of these default values should be suitable, but it is worth checking them. |
| 03:38 | Let’s go through the process of actually configuring a sensor so you have a better idea of how it is handled. |
| 03:44 | For this example, we will look at configuring a manifold inlet pressure sensor. |
| 03:49 | You can do this by either navigating through the tree structure, or we can type manifold pressure in the search bar and the list will populate below with the relevant parameters. |
| 04:01 | Under ‘Sensor’ we have some diagnostic conditions that will define the useable range of the sensor’s readings. |
| 04:08 | The ‘Diagnostic Low’ and ‘Diagnostic High’ values define the voltage limits below and above where the sensor is considered to be in fault. |
| 04:18 | If these limits are exceeded, the ECU will use the default value which in this case is set to 100 kPa. |
| 04:25 | Next we have the actual calibration table for the sensor which defines how the sensor voltage relates to manifold pressure. |
| 04:33 | MoTeC can supply this data for many factory sensors, or if you are using an aftermarket sensor, the data should be supplied with the sensor. |
| 04:43 | Now we have some settings related to the voltage input to the M1. |
| 04:48 | The first parameter is the filter which defines how the ECU will filter the input voltage. |
| 04:54 | The filter setting can be used to reduce the effect of noise on the signal the ECU receives and generally the default value of 20 milliseconds will be adequate in most instances. |
| 05:05 | If you set this value too high, particularly for a critical sensor such as the MAP sensor it can slow down the MAP signal and this can result in driveability or tuneability problems. |
| 05:18 | Next we have some settings dependent on where the particular sensor has been wired to on the ECU. |
| 05:24 | The ‘Resource’ defines which pin the sensor input is wired to, and if we click on this it opens a drop down menu and we can select the correct pin. |
| 05:35 | As we move through and configure the ECU sensors, the list of available inputs becomes smaller as those that are already allocated will disappear from the list. |
| 05:45 | We also have the option of setting the voltage resource from the ‘Edit Input/Output Resources’ page that can be accessed from the ‘Tools’ menu which we looked at earlier in the course. |
| 05:58 | Lastly we need to configure the voltage reference for the input which defines what the input voltage will be referenced against. |
| 06:06 | The M1 has a number of reference voltage (5V) outputs and the correct reference must be chosen based on which connector the sensor is located on. |
| 06:16 | For example if we have a sensor connected to Analogue Voltage Input 2, this is located on connector C on the M150 and we would be using the matching 5V reference pin on connector C which can be chosen in the drop down menu. |
| 06:32 | Once the MAP sensor is calibrated, we will be able to see the inlet manifold pressure being displayed on the time graph. |
| 06:39 | With the engine not running, this should read 100 kPa plus or minus about 5 kPa. |
| 06:46 | If the reading is significantly different, you will need to check your calibration or wiring. |
| 06:53 | Another critical sensor that I want to cover is the throttle position sensor, as the M1 deals with this in a unique way. |
| 07:01 | If we type throttle position in the search box, the list will populate with the required settings. |
| 07:07 | You will notice that the M1 lists this input as ‘Throttle Servo - Bank 1’ which we would normally associate with drive by wire. |
| 07:16 | Don’t worry though as if we are using a conventional cable throttle, the M1 only needs one throttle position input and this is defined as ‘Throttle Servo Bank 1 Position’. |
| 07:27 | We will deal with drive by wire setup a little later in the course if you are configuring that type of engine. |
| 07:35 | Most of the settings here are the same as the ones we already discussed for the MAP sensor, including the voltage resource, reference and diagnostic limits. |
| 07:46 | You will see this time though that we have the parameters ‘Offset’ and ‘Scale’, and both have the ‘Q’ icon beside them. |
| 07:54 | This is how we set the throttle position high and low values in the M1. |
| 07:59 | We can start by selecting the ‘Offset’ parameter, and with the throttle completely closed, press ‘Q’. |
| 08:06 | In this instance, ‘Offset’ refers to the offset or difference from the zero volt reference. |
| 08:14 | This will lock in the closed throttle voltage. Now we can select the ‘Scale’ parameter and go to full throttle. |
| 08:22 | Pressing ‘Q’ will now calibrate the ratio of throttle position to voltage. |
| 08:28 | With this correctly calibrated we should now be able to see the throttle position move smoothly from zero to one hundred percent on the time graph as we move the throttle through its travel. |
| 08:39 | Calibrating the rest of the sensors follows the same process we have just covered. |
| 08:44 | Any time a sensor is calibrated, it is important to view the sensor input the ECU is reading and make sure it is sensible. |
| 08:52 | We can view these in the time graph on the right, or we can press ‘Control’ plus ‘C’ or the squiggle icon to display the channel values. |
| 09:01 | At the bottom of the worksheet we have the ‘Sensor Warning Setup’ which we can use to configure a warning mode if any of the sensors move outside our desired operation range. |
| 09:11 | We looked at how we can configure these in the last section dealing with the ‘Engine Speed Limits’ page so there is no need to cover this again. |
| 09:20 | The next worksheet is the ‘Sensors Optional’ page which offers a few optional sensors and as I mentioned, these can be used to help refine the ECUs operation. |
| 09:31 | As with the critical sensors, its important to make sure the default values here are realistic if you are not using any of these sensors. |
| 09:40 | The actual setup of the optional sensors is identical to the technique we have just covered so there is no need to repeat this. |
| 09:50 | One optional sensor that can be worth considering is a fuel pressure sensor. |
| 09:55 | The M1’s fuel model relies heavily on calculated fuel flow through the injectors, and the actual fuel delivery will vary depending on the differential fuel pressure. |
| 10:05 | Adding a fuel pressure sensor allows the M1 to accurately measure differential pressure across the injector instead of assuming. |
| 10:15 | If we expand the tree for the fuel pressure sensor, there are a couple of additional options to setup. |
| 10:21 | First we need to define if the sensor is gauge, absolute or differential. |
| 10:27 | Next we have the ‘Regulator Reference’ parameter which defines if the fuel system runs a constant pressure or is referenced to the inlet manifold. |
| 10:38 | The remaining settings for the calibration and voltage resource are the same as the other sensor inputs. |
| 10:44 | The last worksheet we need to look at here is the ‘Sensors Other’ worksheet. |
| 10:49 | As I said at the start of this module, these inputs are not critical to the actual engine operation, however we can use them for data logging or for controlling other outputs. |
| 11:00 | The setup is identical to the procedure we have already looked at although with these inputs, we do have the option of receiving the input via CAN. |
| 11:10 | If we expand the tree out and look at ‘Exhaust Pressure’ we can define which CAN slot the information will be received on. |
| 11:17 | We can also define if the data will be calibrated or raw, and if it is calibrated, what the scaling factor for the CAN value is. |
| 11:26 | This completes the sensor calibration and we can move on to the Ignition Configuration worksheet. |
