Haltech E6M - Manual (Page 96)

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16.3 Bypass Air Control (BAC) Valve
16.3.1 Description
The BAC allows you to use a valve to operate Idle Air Control. Traditionally, Idle Air Control
(IAC) motors have been used but require knowledge of either how many steps they have or
experimentally finding the correct operation. BAC valves only require a period (ms) setting as
opposed to the number of steps, min steps in, max steps out, etc as required with stepper
motors. The period in milliseconds is the operating frequency for the particular solenoid. This
frequency can be approximated but an accurate value will help by giving the best response
times. Consult factory information on your particular solenoid if the operating frequency is
unknown: a typical value 10ms.
The operation is fairly straightforward: each BAC solenoid will have its own operating
frequency. By continually operating the valve at this frequency, you can then vary the duty
cycle to move the valve in or out. The duty cycle varies from 0 to 100% whilst the operating
frequency is maintained constant.
16.3.2 Using BAC Solenoids
The BAC settings are mostly done in the Idle Air Control section on the Output Options Page.
Firstly, set a PWM output to operate as BAC and set the operating period. Then go to the
Output Options Page. Select the Idle Air Control. Note that the Idle Speed will be disabled
because you are using a BAC output to do Idle Control and not an IAC Stepper motor. Go
through the settings, as you would do if you were configuring Idle Control for a stepper
motor. A full description of the procedure is available in “14.2 Using the Idle Speed Motor”.
Remember that you are using a BAC solenoid and not a stepper motor so not all of the
settings in 14.2 will relate to BAC.
16.4 Dual Intake Valve Control (DIV)
Some late model engines possess two tuned intake manifolds. One intake tract remains shut at
lower rpm where there is less airflow, then opens as airflow demands increase. This provides
a broader torque curve. The DIV function controls the solenoid that operates this valve.
In order to use the DIV function, you will need the following:
- a two wire solenoid valve mounted in the air intake (already on the engine);
- E6H/E6M programming software and cable.
Wire the solenoid to the appropriate output, taking note of voltage polarity. (Some solenoids
are non-polar.) Run the E6H/E6M programming software in ONLINE mode and select the
Dual Intake Valve function on the appropriate channel. There are two values to be set.
Switch On RPM
This is the engine speed at which the solenoid is to be energised.
Switch Off RPM
This is the engine speed at which the solenoid is to be de-energised.