大陆公司PM传感器介绍
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Smart Particulate Matter (PM) Sensor
Particulate Matter (PM) Sensor What is soot ?
3 Main components of Particulates in Exhaust Gas: Elementary carbon (EC) Organic carbon (OC) Sulfates
Important influence factors on PM-composition / OC-EC ratio Transient load and speed conditions Temperature Fuel type, for example: Fe as fuel additive catalyses soot oxidation Biodiesel has less PM and OC (no aromatics / no sulfur)
A Particulate Matter sensor needs to deal with Complex non-unique composition of soot
2 / P S&A
© Continental AG
Particulate Matter (PM) Sensor Sensor Principle
PM deposits on the inter digital electrodes Carbon is an electrical conductor Applied voltage results in an electrical current
Soot Concentration High Medium Low
Regeneration of a PM-saturated IDE
Particulate Composit Contacts IDE
Current I
Measuring range
Regeneration Current I
UM
IDE (Inter Digital Electrodes)
Time t
I=U/R R= f(Soot, TSoot)
Measurement
time t
Sensor Principle: resistive measurement of Soot Particle Load on Sensing Element
3 / P S&A
© Continental AG
Particulate Matter (PM) Sensor Sensor Layout
Electronics Operates the sensor (soot measurement & regeneration) Calibration/Diagnosis of the sensor CAN-Interface to the engine ECU Sensor Element and protection cover IDE finger structure for the soot measurement Heater, used to burn the collected soot
Thermal/Mechanical connection to the exhaust pipe package based on Exhaust Temperature-Sensor (M14, M22 optional) Reuse of fully validated NOx Sensor Hardware Components for the electronics
4 / P S&A
© Continental AG
Particulate Matter (PM) Sensor Sensor Element Layout
Sensor Element Basic Information Thick film technology Alumina substrate (Al2O3) IDE (Inter Digital Electrodes) structure for the PM- measurement (electrode width100 µm) Heater pattern, used to burn the collected PM
Light microscope picture of IDE with PM load
front side: IDE structure
back side: heater structure
Collected Particulates (PM) change the electrical resistance between the IDE fingers
5 / P S&A
© Continental AG
Particulate Matter (PM) Sensor Protection Cover
Protection cover characteristics Influences the soot deposition on the IDE structure Has an impact to the orientation dependency / independency of the measurement
Protection cover generates an orientation independent deposition of soot and protects the (hot) sensor from water splashes
6 / P S&A
© Continental AG