ICM Overview

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Overview

Ignition overview: https://www.youtube.com/watch?v=H8GPSxc_so0

The EMIT Ignition Controller Module (ICM) is an electronically controlled ignition system that features highly accurate and reliable spark control and monitoring capabilities through the use of transistorized inductive technology. The ICM is available in two types: The ICM1 and ICM2, both of which are available in versions with a maximum of 8 or 16 cylinders. The ICM2 is connected directly to the auxiliary drive of an engine for sensing the position of the engine, while the ICM1 uses external timing sources for applications without an auxiliary drive. All ignition modules offer the same feature set and are appropriate for rich-burn or lean-burn combustion and naturally-aspirated or turbo-charged engines fueled by natural gas or propane.

The ICM utilizes transistorized inductive technology to build and transfer energy for spark initialization and control. By using the latest transistor technology, a high speed digital signal processor, and high-energy coils for inductive ignition, the ICM achieves precise and accurate control of a long duration spark that burns beyond that of a capacitive discharge system. The longer spark duration provides reliable combustion of the air/fuel mixture and performs particularly well for poorly mixed air/fuel mixtures, poor quality fuels, and lean air/fuel mixtures. Other benefits of inductive discharge systems include superior misfire performance, higher energy transfer efficiency to the spark, and reduced electromagnetic interference.

Capacitive discharge ignition systems have a higher peak spark voltage, but due to the corresponding short spark duration does not definitely translate to improved combustion. To overcome this, some capacitive systems need to spark multiple times to ensure the mixture is combusted if the original sparks did not ignite or only partially ignited the mixture. Multiple sparks reduce the ability to control peak cylinder pressure and unnecessarily wear coils, wires, and spark plugs. With the longer spark duration of the ICM, one spark provides sufficient energy to ignite the mixture.

For an ICM1, the timing input can be sourced from different locations on the engine depending on the application. In wasted spark mode, the ignition utilizes two magnetic pickups: one for flywheel teeth and one for flywheel index to indicate top dead center of the reference cylinder. By using only two magnetic pickups, no additional sensors are needed for the camshaft timing, which is generally more difficult to access for installation. Alternatively, the ignition can use one magnetic pickup on the flywheel teeth and one hall sensor on the TDC of the camshaft to fire only on compression stroke. Lastly, the ICM1 can have the timing source from a camshaft timing disk, which has a timing mark for each cylinder, and an additional mark for the cylinder that is the reference cylinder.

For an ICM2, no external timing inputs are required. The ICM2 bolts directly to the engine’s auxilary drive location (magneto drive) and uses an internal encoder to detect the position of the camshaft. Internal gearing, in a ratio specific to the engine application, reduces the auxiliary drive to the speed of the camshaft.

Configuration, ignition status, timing adjustment, and diagnostic tools are all presented through the EIM’s 8” touchscreen display. The touchscreen allows the ICM to be fully accessible and utilized without the need for a PC connection, external software, or any chips or keys. If installed with an EMIT AFRC or EMD, the systems can all be accessed through the same display and user interface.

Timing control is designed to automatically advance and retard based on changes to RPM and, optionally, load while also being quickly adjusted manually. Accuracy of the timing is based on engine RPM and is reduced as RPM increases. As an example, timing is accurate within +/-0.090 degrees at 1500 RPM and +/-0.180 degrees at the maximum RPM of 3000. Timing ignition adjustment limited to a range of 5 degrees BTDC and 60 degrees BTDC.

Diagnostic, testing, and control features for the ICM include a range of tools. Conditions for up to eight cylinders at a time can be displayed simultaneously for visual comparison. Various aspects of spark conditions can be setup to provide warnings for potential issues. For engine protection, the ICM offers overspeed and underspeed shutdowns. The ICM can also trigger a warning or shutdown for poor spark performance, such as short spark duration or high misfire count. Other features include verification of timing inputs, verification of coil and harness wiring, top dead center input calibration, compression testing mode, adjustable fuel relay control, adjustable ignition start control, adjustable dwell time, and secondary spark waveform graphing.

Ignition Installation Guide

ICM1 Installation guide can be downloaded here: https://drive.google.com/file/d/15clXhmEJgHOeSvdOKJ7a9EWHjHisDdOb/view?usp=sharing

Ignition Home Screen

The Ignition Home screen (Pg. 400) provides all the necessary information and functionality to quickly observe the system state and access additional diagnostic and setup features. The very top of the screen provides the overall status of the ignition system. The timing box below displays the active timing, and the timing display can be clicked to make adjustments. The center box shows RPM. The lights at the bottom of the screen show the system and timing status, and can be clicked to see diagnostic information. The right box shows spark durations. A security mode of Setup or Engineering is required to access any of the setup and testing features.

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Ignition Home Screen

STATUS

Displays the current status of the ignition system. Possible statuses include:

  • “Configuration/Setup Required” – Configuration and setup have not been completed
  • “Ready to Start” – The ignition system is waiting for timing inputs from the engine
  • “Engine Operation Detected” – Timing inputs have been detected and the ignition is preparing to start
  • “Ignition Started” – Ignition is firing, but the engine is not yet at full running speed
  • “Engine Running” – The engine and ignition are running properly
  • “Engine Running with Warnings” – The engine is running, but warnings are present
  • “Ignition Stopped – Critical Alarm” – The engine has been stopped due to a critical alarm
  • The alarm must be acknowledged in the Alarms screen (Pg. 40) in order to re-start the ignition
  • “External Shutdown” – The shutdown input is grounded
  • “Compression Test Mode” – The ignition is locked out and will not start during cranking
  • “Firing Order Test Mode” – The ignition is firing desired coils with the engine off to verify wiring and operation
  • “Bad Configuration” – There is a setup or configuration issue

TIMING BOX

The timing box on the Ignition Home screen (Pg. 400) displays the active total timing. The timing display can be clicked to go to a larger timing display screen (Pg. 443) to see the three timing components of total timing- rpm advance, load advance, and base timing. The base timing can be adjusted here as well. Values displayed on this secondary screen are:

  • “Total Timing” – Current and active timing of the ignition system
  • Sum of the “Base Timing”, “RPM Advance”, and “Load Advance” timing values
  • “Base Timing” – User adjustable fixed timing
  • Adjusted through the “Advance Base Timing” and “Retard Base Timing” buttons
  • Increments are +/- 0.25°
  • “RPM Advance” – Amount of timing advance added to the total timing for changes in RPM
  • RPM advance timing is configured during the setup process
  • “Load Advance” – Amount of timing advance or retard added to the total timing for changes in manifold pressure
  • Load advance timing is optional and requires a manifold pressure transducer for operation
  • Timing is typically retarded for increases in load or manifold pressure

STATUS LIGHTS

At the bottom of the Ignition Home screen are three status lights- “System”, “Timing”, and “Alarm”. These lamps give a quick snapshot of system status. Clicking on this area will go to the Engine Running Diagnostics and Testing screen (Pg. 420 or 422), to see runtime diagnostics.

Status Light

  • Displays green if the Ignition is connected and powered on, and configuration is complete.

Timing Light

  • Off (white) when the engine is not turning
  • Illuminates green if engine is turning and timing is valid
  • Illuminates in yellow for minor timing issues while the engine is running
  • Illuminates in red if the engine is not running and there are unexpected faults

Alarm Light

  • Off (white) if there are no critical alarms
  • On (red) if there are currently critical alarms

SPARK DURATIONS

The right side of the Ignition Home screen shows the current spark durations. If not relatively steady and similar values, this could indicate a problem with a plug or coil.

Selecting this graph will go to the Cylinder Information screen.

Cylinder Information

Main Cylinder Information Screen

Note: This screen was superseded in EIM version 2.00. See the page "New Ignition Cylinder Information" for the page(s) on 2.00 and newer.

The Cylinder Information screen (Pg. 440) presents ignition information in bar graph form and provides access to additional individual cylinder information. It is accessed by selecting the spark bar graphs on the Ignition Home Screen.

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Ignition Cylinder Information Screen

The following information can be visually compared through the bar graphs, and can be changed by clicking on the data item above the bar graph and selecting a different data item. The current average is highlighted and an average bar is shown for that data value.

  • “Spark Duration” – Spark time for each cylinder
  • “Cyc-to-Cyc Variation” – Changes in spark duration from cycle to cycle for each cylinder
  • “Dwell Time” – Amount of time the ignition coil is being charged in ms
  • “Total Timing” – Displays timing for each cylinder
  • “Misfires” – Displays accumulated misfires for each cylinder. If in Engineering access mode, this value can be cleared.

If a bar graph background flashes yellow, then a misfire occurred on that cylinder. If this happens frequently on a given cylinder, the spark plug and coil should be checked.

SPARK GRAPHING

The Spark Graph screen (Pg. 448) is accessed by selecting the “Spark Graphing” button from the Cylinder Information screen (Pg. 440).

To graph a spark waveform, select the cylinder to capture and press the “Capture Spark” button. A healthy spark should be drawn as shown below. Unhealthy sparks will be abnormally short/long or have intermittent jogs within the low duration of the spark.

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Spark Graph Screen

INDIVIDUAL CYLINDER INFORMATION

The Individual Cylinder Information screen (Pg. 442) presents comparison data for the particular cylinder selected from the Cylinder Information screen (Pg. 440). The data displayed compares various information from the cylinder to the engine average. Data is displayed in table form as well as graphically through bar graphs.

Individual cylinder timing is adjustable from this screen. Selecting the “Advance Cylinder Timing” and “Retard Cylinder Timing” buttons adjusts the offset from the Total Timing of the system. Timing offsets are in increments of 0.25°. Security access of Setup or Engineering is required to adjust the timing.

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Ignition Individual Cylinder Information Screen

Setup

After physical installation and wiring is completed, the ICM must be configured prior to operation. To configure, navigate to the Ignition Setup screen (Pg. 402). Security access of Setup or Engineering is required. Note that step 1, “Engine and Timing Setup” is different for ICM1 and ICM2 models.

STEP 1: ENGINE AND TIMING SETUP- ICM 1

Step 1 of the setup process involves identifying engine parameters and sparking type.

  • “Cylinder Count” – Number of cylinders of the engine
  • “RPM Overspeed Trigger” – RPM at which the ignition will kill due to overspeed or runaway condition
  • “Flywheel Tooth Count” – Number of teeth on the flywheel for one revolution
  • If there are any teeth missing or broken on the flywheel, the original tooth count should be entered. The ICM will compensate for the missing teeth automatically.
  • “Four-Cycle Timing” – Spark type of the ignition if 4-Cycle combustion type is selected. Navigates to 4-Stroke Timing Selection screen (Pg. 410)
  • “Wasted Spark” will fire ignition on both the compression and exhaust strokes
  • “Camshaft TDC- Hall Effect” will utilize a Hall effect sensor to indicate the TDC of the compression stroke of the reference cylinder, and does not use a flywheel TDC
  • “Camshaft TDC- Magnetic Pickup” will use a magnetic pickup on the cam to indicate TDC of the compression stroke, with the MPU plugged into the “Flywheel TDC Index Mag
  • Pickup” port (though in reality there is no flywheel TDC sensor)
  • “Camshaft Timing disc”- will use a magnetic pickup or hall (depending on option selected) on a cam timing disk to sense the camshaft position. This timing disk will have one mark (gap or magnet) for the TDC of each cylinder, and one extra mark to indicate the reference cylinder. This mode is often used if a digital ignition was already installed. If using a timing disc but the layout is unknown, choose an option and use the "Timing Disc Test" page after completing setup.
  • The “Sensor Locations” list shows where the Ignition is expecting the various timing sensors for the selected mode.
  • "Cam Angles" (EIM > 2.00 and ICM > 1701 only): For most engines, this is "Normal", which signifies that cylinders fire in even gaps. If "Asymmetrical" is selected, then two angles can be specified to configure the ignition to use two opposite angle gaps between cylinders. For example, if the first angle is 60 and the second 120, then the second cylinder will fire 60 (flywheel) degrees after the first cylinder, and the third cylinder will fire 120 degrees after the second cylinder, and so on.

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Step 1: Engine and Timing Setup- ICM1

Select the “Firing Order >” button to continue.

STEP 1: ENGINE AND TIMING SETUP- ICM 2

Step 1 of the setup process for the ICM2 defines the following settings.

“Combustion Type” – 4-Cycle or 2-Cycle

“Cylinder Count” – Number of cylinders of the engine

“RPM Overspeed Trigger” – RPM at which the ignition will kill due to overspeed or runaway condition

STEP 2: CYLINDER FIRING ORDER

Step 2 is used to define the engine firing order for the number of cylinders defined in Step 1. Use the number keypad on the right to set the cylinder number to the firing order. The firing order can usually be found on the engine block.

If needed, cylinders can be appended with “L” and “R” letters for left and right banks. If utilizing the “L” and “R” designations, all cylinders should include either an “L” or an “R”.

If applicable, a pre-defined engine can be selected on the right side of the screen to fill in the firing order.

Select the “Harness ID >” button to continue.

STEP 3A: HARNESS IDENTIFICATION

Step 3A is used to identify harness connected to the ICM.

Use the “Harness P/N” combo box to select the harness part number. The part number can be found on the tag attached to the coil harness. If the harness part number is not in the list of harnesses, select the “Other” option and enter the 18-digit harness key found on the part number tag.

Select the “Next >” button to continue.

STEP 3B: HARNESS SETUP

Step 3B is used to identify which harness and wire is connected to each cylinder.

Use the “Harness” buttons to toggle between “Harness 1” and “Harness 2” if the installation required two ignition coil harnesses. Use the combo boxes to identify what colored wire is connected to each cylinder. The harnesses are labeled at the connector on the printed circuit board internal to the ICM enclosure.

If the ICM8 was installed, which only supports up to eight cylinders, the harness used is “Harness 1”.

Select the “Timing >” button to continue.

STEP 4: TIMING ADVANCE

Step 4 is used to set the ignition timing for the RPM range of the engine, or select a timing map if available.

After “Map Type” any built-in maps will be listed, along with “Custom”. Built-in maps are preconfigured timing maps for a particular engine that will adjust the timing for speed and load changes, and have been specifically setup for that engine. If a built-in map is not available, the “Custom” map type can be selected for user-selected timing ranges.

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RPM Timing Advance (Prebuilt Map Selected)

CUSTOM RPM TIMING

The timing and RPM information entered under “Custom” map type will allow the timing to be automatically adjusted based on user-configured changes to RPM. The data entered under this step can be changed or modified later if needed.

To set the RPM advance, timing must be specified for a low RPM value and a high RPM value.

The timing will automatically be interpolated between the two specified RPM values. If the RPMs exceed the two RPMs provided, the timing will be clipped respectively.

Select the “Review >” button to continue.

STEP 5: SETUP REVIEW

Step 5 is used to review the setup configuration.

If the information is correct, press the “Setup Complete” button. If not, press the “< Back” button to modify the settings.

(ICM2 ONLY) STEP 6: ENCODER CALIBRATION

For the ICM2 only, the encoder has to be calibrated after installation. This step saves the “zero point” of the encoder as installed, and also the rotation direction of the auxiliary shaft.

Once setup is complete (step 5 above), the encoder calibration can be performed. Ensure that the engine is at TDC of the compression stroke of the reference cylinder.

If a magneto was previously installed on the engine, it will be easiest to check for compression TDC before removing the magneto by aligning the red marks. The flywheel TDC marking should still be used for fine alignment. After the engine is at TDC of compression for the reference cylinder, the ICM2 can be installed in any arrangement, but be sure not to crank the engine until this calibration step.

Navigate to the encoder calibration page by clicking on “Setup and Testing” on the ICM Home page, then “Encoder Install Calibration”. On the calibration page, click “Start Calibration” when you are sure the engine is at TDC. Once the calibration shows active, crank the engine for several seconds until the “Calibration Active” goes from “Yes” to “No. The result should say “PASS”, at which point calibration is complete.

Timing Adjustment

The active ignition timing is a sum of "Base Timing", which is a fixed manual timing adjustment, and either a prebuilt or custom timing map.

  • For a prebuilt timing map, which is made for a specific engine, the ignition will adjust timing based on changes to speed and load (if a manifold pressure sensor is present). The map is also adjusted based on user-entered elevation and fuel specific gravity, if known. The Base Timing offsets the timing map some amount if desired.
  • For a custom timing map, the user specifies an RPM Advance, which adjusts timing based on changes to RPM, and a Load Advance, which adjusts timing based on changes to load. The Base Timing is also used to quickly adjust the timing up or down. A custom map can also be used for fixed timing by setting the RPM advance values to the same advance.

The total timing is limited to the range 5 to 60 degrees BTDC, and if out of range it will be clipped.

BASE TIMING

Base Timing is a manual timing adjustment that is fixed. The purpose of Base Timing is to allow the operator to quickly advance or retard the timing in small increments without having to modify the RPM Advance, Load Advance, or map settings.

Base Timing can be positive (timing advance) or negative (timing retard). Base Timing adjustments increment in 0.25° steps. Base timing is adjusted on the Timing Display page (Pg. 443), which is accessed by clicking on the small timing graph on the Ignition Home screen.

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ICM Timing Display screen

If a prebuilt timing map is selected in ignition setup, the base timing will start at 0 degrees. The base timing can still be adjusted to raise or lower the timing. If in a prebuilt timing mode, it is not recommended to have base timing outside the range +/- 5 degrees.

SELECTING A TIMING MAP

A timing map is normally selected during ignition setup at step 4. To change after setup, go to "Setup and Testing", then "Timing Map / RPM Advance / Load Advance". On the left side of this screen the user can select a prebuilt timing map for this engine, or can select "Custom" for a custom map.

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Timing map selection screen with "Custom" selected

CUSTOM MAP

If not using a built-in timing map, RPM Advance is used to automatically adjust ignition timing for changes to engine speed. RPM Advance is configured during the setup process but can be adjusted at any time through the above screen. Security access of Setup or Engineering is required.

For the low RPM timing:

  • Set the low RPM value to the cranking RPM or at the lower range of operating RPM, whichever is desired
  • Set the timing the ignition should be running at that specific RPM

For the high RPM timing

  • Set the high RPM value to the maximum operational RPM
  • Set the timing the ignition should be running at that specific RPM

The timing will automatically be interpolated between the two specified RPM values. If the engine speed runs below or above the RPM values, the timing will clip to those respective values.

Timing is typically advanced, or increased, from TDC as RPM increases.

LOAD ADVANCE

If not using a built-in timing map, Load Advance is used to automatically compensate ignition timing for changes in engine load. In order to configure and utilize the Load Advance feature, a manifold pressure sensor (EMIT #13207) is required. The manifold pressure sensor can be directly wired to the ICM or wired to an AFRC or Governor, if equipped. Load Advance is configured on the Load Advance screen (Pg. 431) and requires Engineering security access. This page can be accessed from the "Timing Map Selection" screen if "Custom" is chosen, by selecting the "Load Advance" button.

When setting up Load Advance, use the “+/–” button in the keypad to switch between pressure units and advance or retard timing. For pressure, positive units are in PSI boost, and negative units are in “Hg vacuum. For timing, positive units are timing advance and negative units are timing retard.

For the low load timing:

  • Enter the manifold pressure value that represents low or moderate load on the engine
  • Enter the degrees of additional timing advance or timing retard at this load point
  • This is typically left at “0.00°”
  • Enter the percent load of the engine at this manifold pressure

For the high load timing:

  • Enter the manifold pressure value that represents high load on the engine
  • Enter the degrees of additional timing advance or timing retard at this load point
  • Enter the percent load of the engine at this manifold pressure

When setting up Load Advance, keep in mind that the timing values are in addition to existing RPM Advance and Base Timing settings. For example, timing may already configured, but Load Advance is required to adjust timing for load swings. A typical Load Advance setup may have 0.0° at low load and -5.0° timing retard at high load.

The Load Advance screen (Pg. 431) also allows a load calculation to be configured. The “Percent Load” values provided will calculate the load based on changes to the manifold pressure. These values are for display only and are intend to give the user an idea of the current load on the engine.

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Load Advance Setup Screen

INDIVIDUAL CYLINDER TIMING

The timing for each cylinder can be offset from the Total Timing of the ICM. Timing offsets are in increments of 0.25° of either timing advance or timing retard. An individual cylinder can be offset at most +/- 3.0° from the global timing value. Like global total timing, an individual cylinder’s total timing will be clipped to the range 5° - 60° BTDC.

Cylinder offset timing is set on the Individual Cylinder Information screen (Pg. 442) of each cylinder, which is found by selecting the desired cylinder on the Cylinder Information screen (Pg. 440). A security access mode of Setup or Engineering is required to adjust the timing.

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