Assessment of an Advanced Method for Measurement of the Solid Carbonaceous (Soot) Component of Mobile Source Particulate Matter

This page updated November 23, 2005.

Artium Technologies

Assessment of an Advanced Method for Measurement of the
Solid Carbonaceous (Soot) Component of Mobile Source Particulate Matter

Technology and Innovation
Laser-Induced Incandescence (LII) is an innovative method for measuring soot (solid carbonaceous) particulate matter (PM) concentration. The method allows in situ measurements in the direct exhaust, or after dilution, with exceptional sensitivity to low soot concentrations. It can also handle a very high range (1,000,000:1) in soot concentration. The method involves the rapid heating (in approximately 20 nanoseconds) of the particles using a fully enclosed pulse laser light source. Particles are heated to their incandescence temperature and the measured incandescence is related to the volume of particles (soot volume fraction, SVF) in the measurement volume. SVF and soot particle density are used to determine the mass concentration. Measurements are made at the rate of 20 samples per second, providing an unparalleled real-time capability. The soot primary particle diameter is also measured. Furthermore, development efforts are already underway to: (1) increase the soot concentration measurement sensitivity of the LII instrument and (2) incorporate soot aggregate size measurement capability.
Emission Benefit
A reliable instrument for real-time soot measurements directly from the undiluted exhaust will allow the monitoring and enforcement of vehicular particulate matter emission regulations.

Manufacturers and emissions control systems developers (diesel particulate filters, regenerative particulate traps, etc.) will also benefit having a real-time measurement capability. They will be able to use such instruments during their R&D process and get immediate feedback on the effectiveness of various PM reduction technologies. As a result, engine manufacturers will be able to accelerate their development cycle, leading to more rapid introduction of low emissions vehicles Ė a direct benefit to California.

The LII method is very specific in only responding to soot particles and hence, allows the detection and measurement of these combustion generated particulates in the presence of other condensed material without interference. The current application would be to mobile sources, although it could be considered for stationary sources and for ambient air quality measurements. The ease-of-use, freedom from frequent servicing and low cost of operation will allow continuous measurements over extended periods.
Project Description
The objective of the proposed project is to have the technical experts from the industry, government, and the academics evaluate the LII 200 and identify areas needing improvement. Field experience will also be used as a mechanism for gaining widespread recognition and acceptance of the instrument. The preliminary testing will be conducted in our laboratory to careful evaluate and verify that the system is properly calibrated and prepared for rigorous field testing. The LII 200 instrument will then be applied to the measurement of exhaust from stationary diesel engines to ascertain how well or how accurately the soot PM emissions may be estimated. Extensive chassis dynamometer tests will be conducted at leading diesel engine manufacturers to evaluate the performance of the LII instrument.

The scope of the evaluation will include the instrument ease-of-use, operational requirements, suitability for long term testing in engine tests cells, data recording and analyses requirements, estimated quality, measurement accuracy, precision, and uncertainty, reliability of the data, sensitivity requirements, and other operational characteristics required of a robust PM measurement instrument. The LII results will also be compared with those from other measurement techniques.

Once the identified requirements and refinements have been incorporated into the instrument, extensive on-road trials will be conducted. We plan to conduct initial on-road trials on the emissions from a suitable diesel pickup truck. This will provide basic information on any further operational requirements for a Portable Emissions Measurement System. Any issues, such as data transfer and recording, vibration, environmental conditions, etc. will be identified. Subsequent to these tests, we plan to conduct on-road tests with medium and heavy duty diesel vehicles.

Funding Source

Funding Amount





ICAT Funded Projects