Checklist Cam Phase Control Setup

This guide shows the recommend method to configure the camshaft control system. Clicking each item (M1 Tune v1.5 only) will select the item and allow you to enter the required information. Once an item has been selected the help, for that item, can be displayed by hitting the F1 key.

The following procedure is for Inlet Camshaft Bank 1. However the same procedure can be used for Inlet Camshaft Bank 2, Exhaust Camshaft Bank 1 and Exhaust Camshaft Bank 2.

Camshaft Phase Control

This system controls operation of a single camshaft actuator.

Camshaft position is detected by a variable reluctance (Magnetic) or Hall sensor. The control valve is driven by the pulse width modulated Inlet Camshaft Bank 1 Actuator output. The output duty cycle is calculated in the Inlet Camshaft Bank 1 Control group using PID with feed forward and a dead band.

The Inlet Camshaft Bank 1 Aim input supplies the target camshaft position value.

Camshaft tooth trigger patterns are defined in Engine Speed Reference Mode. If a suitable mode for the target engine is not defined, MoTeC may need to provide a new Mode.

The following conditions must be met for camshaft position to be measured:

• Set Engine Speed Reference Mode for the desired engine speed / camshaft combination.
• Set Inlet Camshaft Bank 1 Position Resource to the relevant pin.
• Inlet Camshaft Bank 1 Pin Pullup Control must be configured.
• Inlet Camshaft Bank 1 Pin Active Edge must be configured.
• Inlet Camshaft Bank 1 Pin Threshold, Inlet Camshaft Bank 1 Pin Hysteresis, and Inlet Camshaft Bank 1 Pin Debounce should be set to match the sensor type (hall or magnetic).

If the camshaft is in rest position, Inlet Camshaft Bank 1 Position should provide a value of zero. This can be achieved by setting Inlet Camshaft Bank 1 Position Offset. The correct value can be determined when engine rotation produces a Inlet Camshaft Bank 1 Position value with the actuator control being disabled.

The following additional conditions must be met for camshaft control to activate:

• Set Inlet Camshaft Bank 1 Output Resource to the relevant pin.
• For VANOS set Inlet Camshaft Bank 1 Output 2 Resource to the relevant pin.
• Inlet Camshaft Bank 1 Actuator Frequency must be configured.
• Inlet Camshaft Bank 1 Actuator Drive must be configured.
• Inlet Camshaft Bank 1 Actuator Reference Voltage must be configured.
• Inlet Camshaft Bank 1 Actuator Polarity must be configured.
• Inlet Camshaft Bank 1 Actuator Minimum must be configured. Start with 0%.
• Inlet Camshaft Bank 1 Actuator Maximum must be configured. Start with 100%.
• Inlet Camshaft Bank 1 Control Feed Forward must be configured. This value is the duty cycle value which allows the camshaft to maintain its current position. Closed Loop Control will be difficult or impossible until this value is set. This value should be changed in 5% or 10% steps until camshaft movement is observed, then refined so that the camshaft remains stable in the middle of its slew range.

Once camshaft actuator settings are functional (Feed Forward in particular) it is possible to configure closed loop control. Start with all gain values set to zero:

• Set Inlet Camshaft Bank 1 Aim to a mid-slew position (for example 20°). If closed loop fuel control is available, turn it on to minimise the effects of cam timing variations on engine mixture.
• Whilst stepping the Inlet Camshaft Bank 1 Aim value by small amounts (say 5°) increase the Inlet Camshaft Bank 1 Control Proportional Gain in small steps (say 0.5%/°) and observe the time taken for camshaft Inlet Camshaft Bank 1 Position to match Inlet Camshaft Bank 1 Aim.
• Fix the Inlet Camshaft Bank 1 Control Proportional Gain when the time taken to match Inlet Camshaft Bank 1 Position to Inlet Camshaft Bank 1 Aim is no longer reduced.
• Now perform step tests where the Inlet Camshaft Bank 1 Aim value is changed by larger amounts (say from 0° to 40°). Observe the Inlet Camshaft Bank 1 Position overshoot or undershoot and increase the Inlet Camshaft Bank 1 Control Derivative Gain in very small steps, say 0.02%/(°/s ²), until overshoot or undershoot is corrected.
• If longer-term error is still evident (for example 4° of error after 2 seconds), the Inlet Camshaft Bank 1 Control Integral Gain may now be increased by small amounts, for example in steps of 0.2%/(°.s). Observe the reduction in long term error.

Several iterations of the last sequence may be necessary to optimise camshaft control. Typical final values:

• Inlet Camshaft Bank 1 Control Feed Forward: 40% to 60%
• Inlet Camshaft Bank 1 Control Proportional Gain: 0.5%/° to 5.0%/°
• Inlet Camshaft Bank 1 Control Integral Gain: 0.1%/(°·s) to 2.5%/(°·s)
• Inlet Camshaft Bank 1 Control Derivative Gain: 0.001%/(°/s²) to 0.1%/(°/s²)