Boost Control Manual

Boost Control Manual



The Boost Control function is used to regulate boost pressure by controlling the duty of a boost control solenoid. This in turn regulates the air pressure supplied to the wastegate diaphragm.

Note: Due to the large number of pressure units, all default values are quoted in the default unit of kPa.


Wiring Tab

Options

Output Type

One Solenoid

This is the typical setup found on cars which are turbocharged from factory, as well as most after-market turbo suppliers

Two Solenoids

This is most typically used when a pressurized gas is used to manipulate boost. This is typically only needed in drag racing, where the consistency of the regulated pressure is advantageous for tuning. Carbon Dioxide (CO2) is popular pressurised gase to use, as it isn't flammable. Note that the solenoids should have the Normally Closed (NC) and Common (C) ports connected as shown below, and the Normally Open (NO) port blocked completely. 

Trim

Enables a function where an external Trim Module can be used to driver adjustment of boost. When enabled the Trim Tab is available.   (Default = Disabled)

Scramble Boost

Enables a function where a timed amount of extra boost is allowed via a selected input request to the Elite ECU.  When enabled the Scramble Tab is available.

Connections

Boost Solenoid Output

Select an available output wire, typically a DPO (Digital Pulsed Output) that will be wired to your Boost Control 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)

Boost Trim Input

Select an available input wire that will be used for the Trim control. Typically an AVI (Analogue Voltage Input) is selected due to the varying voltage signal used to adjust the boost level.

Scramble Boost Input

Select an available input wire that will be used for the Scramble Boost input. Typically an SPI (Synchronised Pulsed Input) or an AVI (Analogue Voltage Input) is selected and configured as a switch input.


Boost Control Tab

Mode

Select from using Open Loop or Closed Loop Boost control  (Default = Closed Loop)

Open Loop

Open Loop does not use a Target, rather it is a raw amount of duty that the user commands and boost level is tuned by varying this duty.

Closed Loop

Closed Loop Boost Control uses a Target Pressure that the Boost Control system will try to achieve by adjusting duty up or down.

Controlled Parameter

Manifold Pressure

This is the most common selection for Controlled Parameter, and should be used most of the time. 

Waste-gate Pressure

Some specific applications, such as drag racing, will use Wastegate hat pressure control in order to control the boost pressure. This relies on the target pressure being set appropriately for the circumstances, as the control system is no longer looking at Manifold Pressure. 

Obviously, in order to control the wastegate pressure, a wastegate pressure sensor must be used. 

Output Frequency

The frequency to be used by the Boost Control Solenoid.  (Default = 33)

Control Point Offset

Active only when Closed Loop Mode is selected and Controlled Parameter is Manifold Pressure. The amount of Boost Pressure below the Target Pressure that must be exceeded before closed loop Short Term control of duty will commence. Eg. If the Target Pressure is 200kPa, and the Control Point Offset is 50kPa then Closed Loop control will activate when Boost Pressure exceeds 150kPa. Below this amount it will use the Closed Loop Base Duty Cycle table, or it will be fixed to 100% duty under this amount if the Spool Assist is Enabled. A value that is too low can cause the boost to overshoot the target.  A value that is too high can cause Closed Loop to activate while boost pressure is not stable and lead to inconsistent boost control. (Default = 50)

Max Derivative

Active only when Closed Loop Mode is selected. The rate at which the Boost Pressure is increasing must be below this amount before closed loop Short Term control can be active.  This is to avoid boost control from making changes to the output duty while the boost is still climbing at a high rate and is not stable.  (Default = 100)

Overboost Offset

Active only when Closed Loop Mode is selected and Controlled Parameter is Manifold Pressure. If the Boost Pressure exceeds the Target Boost by this amount the Duty will be set to 0%. i.e. the controller will disable. This is to try and prevent an overboost condition that may be dangerous to the engine or user.  (Default = 15kPa)

Enable Spool Assist

Active only when Closed Loop Mode is selected and Controlled Parameter is Manifold Pressure. When Enabled this will cause the Duty to be 100% while boost pressure is positive and is lower than the Target Pressure minus the Control Point Offset.  Eg. If the Target Pressure is 200kPa and the Control Point Offset is 50kPa, when the Boost Pressure is higher than 0kPa and is less than 150kPa the duty is fixed at 100%.  This can be used to help build boost faster. When Disabled the corresponding Closed Loop Base Duty table value will be used instead. In some instances the Spool Assist can cause “spiking” above the target with varying throttle input. (Default = Disabled)

STT Min TPS

Active only when Closed Loop Mode is selected. The Short Term Trim Minimum TPS is the amount of throttle opening that must be exceeded before closed loop Short Term control can activate. This is to prevent the controller from making adjustments while the boost is not stable. Eg. if the throttle opening is low and is holding back the boost from reaching target, the controller would increase the boost duty to try and make the boost reach target. If the throttle is then opened to 100% this will cause the boost to overshoot the target. The STT Min TPS is used to prevent this occurring by only allowing corrections to be made while the boost is able to actually reach the target. (Default = 80)

Related Tables

Closed Loop Base Duty Cycle

Only active when Output Type is selected as One Solenoid. The amount of duty cycle required to make the Boost Pressure reach the Target Pressure.  This table is to be adjusted if the boost pressure is not reaching or is exceeding the desired Target Pressure. Up to 4D mapping is available.

Closed Loop Target Pressure

The amount of desired boost pressure to be targeted by the boost control system.  Up to 4D mapping is available.

Controller Start Delay

A delay time between meeting the conditions for Short Term control, and when control actually activates. This is to prevent the system from immediately making adjustments when boost may not have stabilised yet. Up to 2D mapping is available.

Closed Loop Proportional, Integral and Derivative Gain

This allows mapping of the PID system, which controls the responsiveness of the Boost Control system.  In simple terms the Proportional controls how fast the system will respond relative to how far it is from the target. The Integral is how aggressive the Proportional changes are.    Derivative is used to slow down overshooting the target if the Proportional has been aggressively tuned.  Up to 3D mapping is available for all PID tables.

Open Loop Base Duty Cycle

Only active when Open Loop is selected as the Mode. This is the duty cycle to be used by the Boost Control system, and should be adjusted to reach the desired amount of boost.   No boost target is used in Open Loop and the ECU does not make adjustments to the duty other than what is commanded by the tuner.  Up to 4D mapping is available.


Long Term Trim Tab

Available only when Closed Loop is selected as the Mode of control. The Long Term Trim allows the Elite ECU to learn the Base Duty table over time.

Enable Long Term Trim

Enables the Long Term Trim control. (Default = Disabled)

LTT Min TPS

Long Term Trim control is active only when the TPS is greater than this amount. This is to ensure learning is only possible during stable boost conditions. (Default = 90)

LTT Min RPM

Long Term Trim control is active only when the RPM is greater than this amount. This is to ensure learning is only possible during stable boost conditions. i.e. to not learn when the Target Pressure is not possible to be reached.  (Default = 2500)

LTT Max RPM

Long Term Trim control is active only when the RPM is greater than this amount. This is to ensure learning is only possible during stable boost conditions. i.e. when turbo efficiency can cause the Target Pressure not to be reached. (Default = 7500)

LTT Min Gear

Long Term control is active only when the vehicle is in this gear number or higher. This is to ensure learning is only possible during stable boost conditions, such as a turbo that has not reached operating speed in a lower gear.

Reset

Resets all Long Term correction tables back to zero for all values.

Apply To Base Table

Applies any Long Term corrections to the Closed Loop Base Duty table, and after applying these changes it will reset to zero for all values. 

Related Tables

Long Term Trim Gain

Controls the rate at which the Long Term control can make corrections to the Long Term Trim table.  Larger numbers will learn faster but can cause oscillations, and smaller numbers will make corrections at a slower rate.  Up to 3D mapping is available.

Long Term Trim

Shows the amount of correction the Long Term Trim is making. This table is user definable for axis values, however the axis channels are fixed to be the same as are used for the Closed Loop Base Duty Cycle table. This table can be adjusted by the tuner simultaneously whilst the Long Term Control is making changes.  Up to 4D mapping is available.


Corrections Tab

Allows additional correction tables for the Boost Control to be enabled.  Enabling any of the Correction tables will open a Corrections folder under Boost Control in your list of tables in the ECU Navigator panel.

Overall Correction

When the Mode is set to Closed Loop this will be an overall negative correction to the Target Pressure.  When the Mode is set to Open Loop this will be an overall positive or negative correction to the Duty Cycle. 

Duty Cycle Air Temp Correction

Allows Duty Cycle correction versus Air Temperature over a 2D table.

Duty Cycle Coolant Temp Correction

Allows Duty Cycle correction versus Coolant Temperature over a 2D table.

Duty Cycle Gear Correction

Allows Duty Cycle correction versus Gear Position over a 2D table.

Duty Cycle TPS Correction

Allows Duty Cycle correction versus Throttle Position over a 2D table.

Duty Cycle Flex Fuel Composition Correction

Allows Duty Cycle correction versus Flex Fuel Composition (ethanol percentage) over a 2D table.

Duty Cycle Generic Correction

When enabled the Duty Cycle Generic Correction tab will become available. This table allows for any ECU channel to be used for boost control duty correction mapping.  Up to 3D mapping is available.

Target Pressure Air Temp Correction

Allows Target Pressure Correction versus Air Temperature over a 2D table.

Target Pressure Coolant Temp Correction

Allows Target Pressure Correction versus Coolant Temperature over a 2D table.

Target Pressure Gear Correction

Allows Target Pressure Correction versus Gear Position over a 2D table.

Target Pressure TPS Correction

Allows Target Pressure Correction versus Throttle Position over a 2D table.

Target Pressure Flex Fuel Composition Correction

Allows Target Pressure Correction versus Flex Fuel Composition (ethanol percentage) over a 2D table.

Target Pressure Generic Correction

When enabled the Target Pressure Generic Correction tab will become available.  This table allows for any ECU channel to be used boost control target pressure mapping. Up to 3D mapping is available.


Trim Tab

Only active when the Trim has been enabled in the Wiring tab.

Boost Trim

Trim Max

When the Mode is set to Closed Loop this is the maximum amount of boost target pressure reduction allowed by the external Trim.  When the Mode is set to Open Loop this is the maximum percentage amount of reduction of the duty cycle allowed by the external Trim.   (Default = -100)


Scramble Tab

Only active when Scramble Boost has been enabled in the Wiring Tab. This allows for a temporary increase in boost pressure.

Scramble Boost

Target Offset

Active only when the Mode is set to Closed Loop.  This is the amount of extra boost pressure to be added onto the Target Pressure while the Scramble Boost function is active.

Base Offset

The amount of extra duty cycle to be added to the boost control duty cycle while the Scramble Boost function is active.  When the Mode is set to Closed Loop this value should be “0” and the Closed Loop Base Duty Cycle table should be set accordingly for the extra target pressure that is to be added.

Hold Time

Additional boost is applied as soon as the Scramble Boost button is pressed but will remain active for this amount of time after the Scramble Boost button is released. 

Max Time

The maximum total amount of time that the Scramble Boost can be applied.


Duty Cycle Generic Correction Tab

Active when the Duty Cycle Generic Correction has been enabled.

Conditions Enable

Selected if you want to enable or disable the Duty Cycle Generic Correction table with a certain condition.

Number Of Conditions

Selects the number of conditions, up to 3, that can be used to enable or disable the Duty Cycle Generic Correction table.

Select Channel

Allow selection of the ECU channel to be used

Maths

A selection of Equal To, Not Equal To, Greater Than, Less Than, Greater Than Or Equal To, Less Than Or Equal To that is to be used.

Value

The value the maths must meet

And/Or

Allows conditions to be combined so that multiple conditions must be met to enable or disable the Duty Cycle Generic Correction Table.


Target Pressure Generic Correction Tab

Active when the Target Pressure Generic Correction has been enabled.

Conditions Enable

Selected if you want to enable or disable the Target Pressure Generic Correction table with a certain condition.

Number Of Conditions

Selects the number of conditions, up to 3, that can be used to enable or disable the Target Pressure Generic Correction table.

Select Channel

Allow selection of the ECU channel to be used

Maths

A selection of Equal To, Not Equal To, Greater Than, Less Than, Greater Than Or Equal To, Less Than Or Equal To that is to be used.

Value

The value the maths must meet

And/Or

Allows conditions to be combined so that multiple conditions must be met to enable or disable the Target Pressure Generic Correction Table

 


 


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