Duke

Join the club ! I do not know what the EHA does.

But in Bosch CIS systems, the Lambda Control Cycles the Fuel Frequency Valve and tries to maintain it at a 50% Duty Cycle to achieve correct A/F ratio. The frequency is kept constant - but the on-off duration of the frequency valve is varied to correct the A/F ratio. Lambda controller ultimately gets its signal from the Oxygen Sensor and maintains closed-loop control.

Thanks,

Amit