| 摘要 |
PROBLEM TO BE SOLVED: To provide a soot signal detecting method in measuring particulate matter(PM) in exhaust gas capable of effectively extracting a small pulse signal buried in noise. SOLUTION: Gas G exhausted from an internal combustion engine 1 is collected as sample gas S. The sample gas S is introduced into a hydrogen flame ionization detector 5. An original signal (a) is taken into a signal processing device 8 using a computer from the hydrogen flame ionization detector 5 through a preamplifier 7. For extracting pulse-like soot signals 13, 14 by setting a threshold T for the obtained signal (a), the original signal (a) is taken into a lowpass filter having approximately the same frequency characteristic as the frequency characteristic of the preamplifier 7, and the soot signals 13, 14 are extracted by setting the threshold T for a signal 10 filtered by the lowpass filter. |
