As stricter federal regulations governing particulate matter (PM) emission are phased in from 2004 to 2007, new instrumentation capable of real-time measurements with high sensitivity will be needed. Applications for both extractive sampling and in situ measurements will likely be necessary. While extractive sampling is the simplest to implement, in situ measurement is also needed to characterize engine-out/aftertreatment-in conditions for design optimization and life-cycle simulation.

High-energy, pulsed-laser diagnostics are well suited for these tasks and offer a wide range of measurement capabilities, including:

• Laser-induced incandescence (LII) for soot volume fraction and primary particle size
• Elastic light scattering (ELS) for total volume fraction
• Laser-induced desorption (LID) with ELS (LIDELS) for volatile fraction
• LII + ELS for aggregate size, number, and structure
• Laser-induced breakdown spectroscopy (LIBS) for metallic-ash species and concentration

The CRF's approach is to first develop the techniques in a laboratory environment using research-grade instrumentation and optical components. Researchers work with both real diesel PM from a production engine dynamometer facility and simulated PM generated by a steady-state diffusion-flame flow rig. When a technique has reached the point of "turnkey" operation, the optical experiment is installed on a mobile cart and taken to the facilities of industrial partners for evaluation and demonstration. When a technology is deemed mature, it is passed on to a commercialization partner to be optimized and packaged into a practical instrument. For example, the diagnostic LII has reached the later stage of maturity and is now commercially available.