MoTeC M1 Software Tutorial: Ignition Configuration
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Ignition Configuration
06.30
| 00:00 | Moving on with our initial configuration, the next worksheet we are going to deal with is the ‘Ignition Configuration’ worksheet which defines how the ignition system will operate. |
| 00:11 | We start out by defining the number of cylinders the engine has, as well as which bank each cylinder is located on. |
| 00:19 | This repeats some of the setup we have already seen in this course, so if you have followed the configuration in order, there should be no need to make any changes here. |
| 00:28 | If we move down the list, we have a setting for minimum and maximum ignition timing and this can be used to put a cap on the range of allowable ignition timing. |
| 00:38 | With the potential for a range of compensation tables to effect the final commanded ignition angle, it can be easy for these compensations to become additive and we may result in an unexpected or excessive ignition angle. |
| 00:52 | These settings can also be used to make sure that the final ignition angle always remains within a sensible working range. |
| 01:01 | Next we have ‘Ignition Charge Limit Maximum’ and ‘Minimum’ which tells the ECU how much it can adjust the dwell time for the coil if necessary. |
| 01:10 | This is useful if the engine speed is changing rapidly after the ECU has begun to dwell a coil. |
| 01:16 | In this instance, the ignition event may end up occurring earlier or later than the ECU had predicted as a result of the rapid acceleration or deceleration of the engine. |
| 01:28 | These settings give the ECU the ability to adjust the dwell time as required to maintain accurate ignition timing. |
| 01:35 | In the default package, the dwell time can be adjusted by up to 50% in either direction. |
| 01:42 | In the case of a Distributor based system the min setting should be moved to -90% as it is possible for available dwell time to become much lower than actual requested dwell time. |
| 01:54 | The ‘Ignition Driver Delay’ setting can be used to define how long the delay is between the ECU requesting an ignition event and the spark actually occurring. |
| 02:05 | This can be used to accommodate the natural latency that will exist in any ignition system. |
| 02:10 | If you don’t have accurate information for your particular ignition system, you are best to leave this set to the default of 40 microseconds. |
| 02:20 | Now we have ‘Ignition Driver Spark Duration’ which defines the minimum amount of time it takes for the spark to occur. |
| 02:29 | This parameter ensures the spark can actually occur, which becomes important if we are running a coil with a very long dwell time at high RPM. |
| 02:38 | At some point, the coil doesn’t have enough time to dwell completely and hence the ECU will not allow the coil to dwell again until this amount have time has passed. |
| 02:49 | If this becomes an issue, it probably suggests you should be rethinking your ignition system design though. |
| 02:56 | ‘Ignition Driver Firing Edge’ defines the output edge that the ignition system will fire on. |
| 03:02 | For most ignition systems this will be ‘Falling Edge’ however there are exceptions and setting this incorrectly can result in damage to your coils so if in doubt, contact MoTeC for information relating to your specific ignition system. |
| 03:18 | The M1 also offers the option of using a multi-spark configuration and the next three settings can be used to configure this if desired. |
| 03:29 | The ‘Restrike Angle’ defines the angle in crank degrees over which the restrikes can occur. |
| 03:35 | The ‘Restrike Count’ defines how many ignition restrikes can occur and the ‘Restrike Charge’ defines the percentage of the dwell time that can be used to charge the coil. |
| 03:47 | Multi-spark is not commonly used so there should be little reason to adjust these settings in most installations. |
| 03:55 | If we move down the worksheet, we have a two dimensional table of Charge or dwell time versus battery voltage. |
| 04:03 | This table tells the ECU how long the coil needs to dwell for to achieve its full charge. |
| 04:09 | The values in this table will be higher at low battery voltage where there is less potential available to charge the coils, and conversely it will be lower as battery voltage increases. |
| 04:22 | The correct Charge time is very dependent on the specific coil and MoTeC will be able to provide the correct data for many common coils. |
| 04:32 | Now we can move on to defining the ignition outputs and this will depend on how the ignition system is configured. |
| 04:40 | We have an output listed for each cylinder, and we can then select the ignition output resource associated with that cylinder from the drop down menu. |
| 04:49 | If for example the engine was fitted with a coil on plug ignition system, each cylinder would be configured with an individual ignition output resource wired to the relevant coil. |
| 05:01 | If the engine was fitted with a distributor, we would only have a single output resource in use as there is only one coil. |
| 05:09 | In this case, each cylinder would be configured on the same output resource. |
| 05:15 | Lastly we could have waste spark coil packs fitted in which case one ignition output resource will be allocated to two cylinders on opposing strokes. |
| 05:26 | If you make a mistake in our ignition resource configuration and end up with a configuration that can’t physically work, the ECU will let you know this by displaying a ‘Resource Error’ under the Ignition Diagnostic. |
| 05:39 | Basically the ECU knows from the number of cylinders and the cylinder firing angles which combination of ignition outputs are valid. |
| 05:47 | If the ECU is showing this error the engine will not run and you will need to correct your resource configuration. |
| 05:55 | The next setting we have here is the ‘Ignition Driver Current’ which is basically a current clamp for the ECU which limits how much current should be used to trigger the ignition system. |
| 06:07 | Unless you have some specific information for your ignition system this should be left at 20 milli amps. |
| 06:14 | The last setting we have is the ‘Reference Offset (CRIP) Test’ which we have already looked at in the Ref/Sync worksheet. |
| 06:23 | This concludes our ignition configuration and we can move on to configuring the injectors. |
