Jin Ha Lee

MEMS for TPMS and exhaust of automobiles

In this paper, MEMS devices for TPMS and exhaust monitoring of automobiles are investigated. To counteract to EURO6 regulation, particulate matter sensor for detecting DPF failure of diesel engine as well as accelerometers for calibrating centrifugal effect on pressure measurement and secondary energy harvesting device will have strong effect for car safety. Heater embedded PM sensor uses electro dynamic principle and achieves resolution of 0.25mg/km. The accelerometer for TPMS application focuses on simplicity and low cost using piezoresistive beams and anodic bonding. Electrostatic energy harvester uses only 3 masks and shows symmetrical output of up to 0.73uW/cm3.

Study of NO Storage and Reduction on LNT by Micro Bench-Flow Reactor

We carry out an experimental investigation to analyze the basic performance of NO(nitric oxide) storage in a lean phase and also analyze the NO reduction achieved by the spraying of reducing agents in the rich phase of the exhaust gas in an LNT(Lean NOx Trap). This is an after-treatment system used to reduce the NOx emissions from a diesel engine. If the stored NO is reduced, we measure the outlet concentration downstream of the LNT. The test LNT material used in the experiments is commercial LNT. After being canned into stainless-steel(SUS304), it was built in a micro bench-flow reactor. Compositions of feed gases, three heated and three no heated gases were sprayed upstream of the LNT to analyze the characteristics. We use various temperatures and space velocities as response variables.