Monitoring￿Oxygen￿Sensor - BMW S58 Owner's Handbook Manual

S58￿Engine
8.￿Intake￿Air￿and￿Exhaust￿System
• Rapid￿operating￿readiness￿<￿7￿s
• Higher￿heater￿output￿at￿10￿W
• Increased￿temperature￿compatibility
• Improved￿system￿connector￿with￿better￿contact￿properties
The￿LSU￿5.2￿has￿an￿extended￿measuring￿range.￿It￿is￿thus￿possible￿to￿measure￿precisely￿from￿oxygen
sensor￿0.65￿and￿higher.￿The￿new￿oxygen￿sensor￿is￿operational￿earlier,￿meaning￿exact￿measured￿values
are￿available￿after￿only￿7￿s.
The￿measuring￿dynamics￿of￿the￿sensor￿is￿higher,￿whereby￿it￿is￿possible￿to￿determine￿the￿air/fuel￿ratio
in￿each￿cylinder￿separately￿and￿thus￿also￿control￿it.￿As￿a￿result,￿a￿homogeneous￿exhaust￿flow￿can￿be
adjusted,￿the￿emission￿levels￿lowered￿and￿the￿long-term￿emission￿behavior￿optimized.
8.2.6.￿Monitoring￿oxygen￿sensor
The￿oxygen￿sensor￿after￿the￿catalytic￿converter￿is￿also￿called￿a￿monitoring￿sensor.￿The￿monitoring
sensor￿LSF￿XFOUR￿from￿Bosch￿is￿used￿which￿is￿the￿successor￿sensor￿to￿the￿LSF￿4.2.
The￿LSF￿Xfour￿needs￿the￿DME￿8.6.S￿for￿signal￿analysis￿and￿is￿distinguished￿by￿the￿following
characteristics:
• To￿achieve￿quicker￿response￿characteristics￿after￿engine￿start￿(half￿of￿the￿LSF￿4.2￿value),
a￿stronger￿controlled￿heater￿has￿been￿integrated￿in￿the￿LSF￿Xfour.
• This￿improves￿signal￿stability.
• Less￿space￿is￿required￿for￿installation.
• Thanks￿to￿the￿high￿temperature￿resistance￿and￿optimal￿thermoshock￿protection,￿the
resistance￿to￿condensation￿in￿the￿exhaust￿tract￿following￿a￿cold￿start￿has￿been￿improved.
Depending￿on￿the￿conditioning￿of￿the￿emission￿control￿systems,￿it￿may￿take￿around￿30￿seconds
for￿the￿full￿power￿of￿the￿engine￿to￿be￿available￿after￿it￿is￿started.￿In￿that￿period,￿the￿DME￿control￿unit
activates￿a￿substitute￿program￿that￿is￿required￿in￿order￿to￿quickly￿bring￿the￿emission￿control￿systems
up￿to￿operating￿temperature.￿In￿that￿situation￿the￿full￿power￿of￿the￿engine￿is￿not￿available￿as￿normal.￿If
necessary,￿the￿driver￿is￿notified￿of￿the￿situation￿by￿a￿CCM￿(check￿control￿message).
8.2.7.￿Rear￿silencer
The￿rear￿silencer￿has￿the￿typical￿M￿chrome-plated￿exhaust￿tailpipe￿trims.
The￿electrical￿exhaust￿flaps￿are￿activated￿directly￿by￿the￿DME￿by￿a￿pulse-width￿modulated￿signal.
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