The following controls relate to fuel injector and ECU injection driver setup. Typically these will be set once during the initial setup procedure and left unaltered after that.
·Fuel Injector Wiring and Setup Technical Notes - Information to help with the injector configuration.
·Injector Deadtime - Dead time table for the primary injectors.
·inje - Information on how to compensate for the non-linear flow of injectors at short pulse widths.
·Injector Flow @ Rated Pressure - How much fuel flows through the injector at the rated pressure. Only used when Fuel Equation Mode is set to Modelled or Modelled - Multi Fuel.
·Injector Rated Fuel Pressure - This is the differential fuel pressure that the injectors were flow rated at. Only used when Fuel Equation Mode is set to Modelled or Modelled - Multi Fuel.
Other options relating to the fuel delivery method and fuel calculation are found in the Fuel Setup menu.
There is always a delay between the injector being energised and the injector actually opening. Likewise, there is a small delay between the injector being de-energised and the injector closing. The opening time is considerably longer than the closing time. The overall result is that less fuel will flow for a given pulse width than would be expected with an 'ideal injector'. To compensate for this the injector pulse widths are increased to compensate for this 'dead-time'. The dead-time for a given injector is a function of the battery voltage, differential fuel pressure and the type of injector control (saturation or peak and hold). A typical dead-time at 3 Bar differential fuel pressure and 14 volts is just under 1ms (ms = millisecond = 1 thousandth of a second).
In applications with a linear 1:1 fuel pressure regulator (ie not a rising rate regulator), the differential fuel pressure (difference between manifold pressure and fuel pressure) will be constant. Therefore the only variable that is changing will be the battery voltage (this changes with electrical load and sometimes engine speed). Without correction, the changes in dead time will cause the engine to run lean when the voltage drops. If the Injector Voltage Correction is properly setup then changes in the battery voltage will not affect the air/fuel ratio.
The injector dead-time table allows the dead-time for different battery voltages to be entered. The values represent the dead-time in milliseconds. These should increase with falling system voltage.
The following settings are available:
·Deadtime Table - This selects if a 2D table with the X axis fixed to battery voltage or a 3D table with configurable axis is used. This setting affects the primary and secondary Injector Dead Time Table
·Injector Dead Time Table - The values entered in this table are the time in ms that will be added to Inj Effective PW (injector effective pulse-width) to compensate for injector dead time.
Fuel Pressure Dead Time Correction
When using a 3D dead time correction table dead time can also be corrected for changes in fuel pressure. This is useful when using a rising rate fuel pressure regulator. To do this set the Y axis of the 3D Injector Dead Time Table to Differential Fuel Pressure. For this to work correctly a MAP sensor and Fuel Pressure sensor must be connected to Analog Volt channels on the ECU.
Injector Short Pulse Width Adder Table
The Injector Short Pulse Width Adder Table compensates for the non-linear flow characteristics of fuel injectors when at low pulse-widths.
Below 4.0 ms fuel injectors often have non-linear flow, to correct for this area of non-linear flow Link G4X ECUs have primary and secondary Injector Short Pulse Width Adder Tables. The secondary table is used only on engine setups that use staged injection.
Most injector data sheets provide the required information for the Injector Short Pulse Width Adder table, often this information will be named 'GM Small Pulse Adder' data. The table below is an example of this data for the Injector Dynamics ID1000 injector.
Effective Pulse Width |
0.000 |
0.125 |
0.250 |
0.375 |
0.500 |
0.625 |
0.750 |
0.875 |
1.000 |
1.125 |
1.250 |
1.375 |
1.500 |
1.625 |
1.750 |
1.875 |
Short Pulse Width Adder |
0.000 |
0.173 |
0.134 |
0.101 |
0.077 |
0.059 |
0.047 |
0.038 |
0.031 |
0.027 |
0.023 |
0.021 |
0.019 |
0.017 |
0.015 |
0.013 |
Effective Pulse Width |
2.000 |
2.125 |
2.250 |
2.375 |
2.500 |
2.625 |
2.750 |
2.875 |
3.000 |
3.125 |
3.250 |
3.375 |
3.500 |
3.625 |
3.750 |
3.875 |
Short Pulse Width Adder |
0.011 |
0.010 |
0.009 |
0.008 |
0.006 |
0.005 |
0.003 |
0.001 |
0.000 |
0.000 |
0.000 |
0.000 |
0.000 |
0.000 |
0.000 |
0.000 |
Injector Dynamics ID1000 Short Pulse Width Adder Table (units in msec).
Warning
The correct numbers for the Short Pulse Width Adder Table will vary significantly with injector model. If accurate data is not available set the whole table to zero.
Injector Flow @ Rated Pressure
The injectors flow rating is used as part of the ECUs fuel equation. This is the volume of fuel (in cubic centimeters) the injector will flow per minute.
Injector flow numbers are always given or measured at a particular differential pressure. Any number entered for Injector Flow @ Rated Pressure must be accompanied by also entering the correct Injector Rated Fuel Pressure setting. Note, there is no such thing as just "1000cc injector". They are ALWAYS 1000cc at a particular differential pressure!
Note: This setting is only used when the Fuel Equation Mode is set to Modeled or Modeled - Multi Fuel.
Note: When using Single-Point Group mode this value must be the flow rate per injector drive. (e.g. two injectors wired to each drive would need the specified flow rate to be double the flow rate of an individual injector).
Note: When using Multi-Point Group mode it is assumed that there is one injector per cylinder and this is the flow of one cylinders injector.
This setting is also used to determine the Instantaneous Fuel Consumption parameter.
This is the differential fuel pressure that the injectors were flow rated at. Refer to the Injector Flow @ Rated Pressure setting. This setting is used as part of the fuel calculations injector flow / fuel pressure compensation.
Note: This setting is only used when the Fuel Equation Mode is set to Modeled or Modeled - Multi Fuel.
Traditional Mode Fuel Flow Table
This setting turns on or off the Fuel Flow Table which is used for approximating fuel usage when using traditional mode. More specifically this table is used to update the Accumulated Fuel Consumption runtime which is in turn used to update Inst. Fuel Consumption, Accumulated Fuel/Distance, Instantaneous Fuel/Distance and Fuel Left values.
The output of the Fuel Flow Table is treated as the flow rate of the injectors in cc/minute (the flow rate of 1 injector not the cumulative flow rate of all injectors). It is recommended to use Differential Fuel Pressure on one axis when a Fuel Pressure Sensor is present or MGP when there isn't one (Differential Fuel Pressure can be used on a constant fuel pressure system (not MAP referenced) if the Fuel Pressure Error Value is set to the correct Fuel Pressure).
Note: The Fuel Flow Table is intended to provide an approximation of the actual fuel usage and the fuel usage accuracy depends on the accuracy of the Deadtime Table values, SPWA Table values and the Fuel Flow Table values.
Note: This setting and associated table is only used when the Fuel Equation Mode is set to Traditional (Modeled fuel modes use the Injector Flow @ Rated Pressure and Injector Rated Fuel Pressure values).
This setting is used to correct the fuel usage values without having to change the injector data settings. It acts as a multiplier to the amounts of fuel used being added to the accumulated fuel use and so also affects the instantaneous and fuel/distance values. This setting doesn't alter the previous values, only new fuel used values being added to them. This setting is to be used when it is impractical to correct the injector data but more accurate fuel usage values are desired.