Evaporative Emissions Control
The Evaporative Emissions Control (EVAP) function allows for control of a purge control solenoid, so that a controlled amount of vapour from the fuel tank can be supplied to the engine intake instead of venting harmful emissions into the atmosphere. The solenoid is controlled by a PMW duty signal.
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Wiring Tab
Connections
EVAP Output
Select an available output wire, typically a DPO (Digital Pulsed Output) that will be connected to the Evap solenoid.
Active State
Controls the direction of duty used to open or close the solenoid. Low will close the solenoid with 0% duty and open the solenoid with 100% duty. High will close the solenoid with 100% duty and open the solenoid with 0% duty. (Default = Low)
EVAP Tab
Frequency
Typically a very low frequency is used for Evap solenoids, typically 2 to 20Hz, to allow fine control between closed and small flow amounts. (Default = 5)
Related Tables
Duty Cycle (O2 Active)
Active only when the O2 Control function is enabled and the system is actively in closed loop control. Under these conditions the O2 Control function can correct for more vapour than when in Open Loop, without affecting the engine. As such it is normal to see larger duty values in the O2 Active table compared with lower values in the O2 Inactive table.
Duty Cycle (O2 Inactive)
Active when there is no closed loop control of the fuel system in active use. It is normal to use lower duty values in the O2 Inactive table compared with higher values in the O2 Active table.
Generic Correction
Allows for a user selectable condition to control the duty. Eg. Limiting duty with TPS.
Coolant Temp Correction
Allows for correction of the duty with coolant temperature. It is normal operation to not allow excessive vapour to enter the intake while and engine and catalytic converters are not at operating temperature. Typically it will be expected to use large negative numbers under cold temperatures to reduce the duty under these conditions. Up to 2D mapping is available.
Fuel Tank Pressure Correction
Active when a Fuel Tank Pressure Sensor is being used to give feedback on the pressure in the vapour line. Default this map has zero for all values. Up to 2D mapping is available.