Technical data

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Mini HFM for secondary air system
A mini HFM measures the secondary air mass
in the intake pipe of the secondary air pump.
This monitoring facility has proven necessary
in view of the ever lower exhaust emission
values.
Primary oxygen sensor (control sensor)
The familiar oxygen sensors LSU 4.9 with
continuous characteristic are used as the
primary oxygen sensors (control sensors).
They are installed in the intake funnel of the
near-engine catalytic converters.
Secondary oxygen sensor (monitor sensor)
The secondary oxygen sensors (monitor
sensors) are the already familiar discontinuous
characteristic sensors LSH 25.
Exhaust gas temperature sensor
The exhaust temperature sensors are
designed as NTC measuring elements.
The sensor can detect temperatures of up to
approx. 1,200 °C.
This sensor is mainly used to protect the
catalytic converters.
Pressure accumulator shut-off valve (VANOS)
The shut-off valve ensures that the high
pressure engine oil remains in the pressure
accumulator after turning off the engine.
The valve is therefore closed when no power
is applied and is opened on request by the
DME (no proportional opening).
11 - Mini HFM