ISO 8178-9:2019 往復内燃エンジン—排気エミッション測定—パート9：不透明度計を使用して圧縮点火エンジンからの排気ガス煙エミッションを測定するためのテストサイクルとテスト手順 | ページ 6

3.1

exhaust gas smoke

visible suspension of solid and/or liquid particles in gases resulting from combustion or pyrolysis

Note 1 to entry: The exhaust gas smoke may be black smoke, blue smoke, brown smoke or white smoke depending on the components present in the exhaust gas after the combustion or pyrolysis process. Black smoke (also referred to as “soot”) is mainly due to the presence of carbon particles. Blue smoke is usually due to droplets resulting from the incomplete combustion of fuel or lubricating oil. Brown smoke is due to the presence of NO₂ in the exhaust gas. White smoke is usually due to condensed water and/or liquid fuel.

3.2

transmittance

τ

fraction of light transmitted from a source through a smoke-obscured path which reaches the observer or the instrument receiver

Note 1 to entry: Transmittance is expressed as a percentage.

3.3

opacity

N

fraction of light transmitted from a source through a smoke-obscured path which is prevented from reaching the observer or the instrument receiver

Note 1 to entry: Opacity is expressed as a percentage.

Note 2 to entry: .

3.4

effective optical path length

L_A

length of the smoke-obscured optical path between the opacimeter (3.8) light source and the receiver

Note 1 to entry: Effective optical path length is expressed in meters and corrected, as necessary, for non-uniformity due to density gradients and fringe effect.

3.5

standard effective optical path length

L_as

measurement used to ensure meaningful comparisons of quoted opacity (3.3) values

Note 1 to entry:L_as values are defined in 9.1.4.

3.6

light absorption coefficient

k

fundamental property quantifying the ability of a smoke plume or smoke-containing gas sample to obscure light

Note 1 to entry: Light absorption coefficient is expressed in reciprocal meters (m⁻¹).

3.7

Beer-Lambert law

mathematical equation describing the physical relationships between the light absorption coefficient (k) (3.6) , transmittance (τ) (3.2) and effective optical path length (L_A) (3.4)

3.8

opacimeter

instrument used for continuous measurement of opacity (3.3) and light absorption coefficient (3.6) of the exhaust gas

3.9

full-flow opacimeter

instrument which measures all flow of exhaust gas passing through the smoke measuring chamber

3.10

full-flow end-of-line opacimeter

instrument which measures the opacity (3.3) of the full exhaust plume as it exits at tailpipe

3.11

full-flow in-line opacimeter

instrument which measures the opacity (3.3) of the full exhaust plume within the tailpipe

3.12

partial-flow opacimeter

instrument which samples a part of the total exhaust flow and passes the sample through the measuring chamber

3.13

opacimeter rise time

X

overall rise time of the instrument

Note 1 to entry: The definition of the term “opacimeter rise time” used in this document is equal to the definition of the term “opacimeter response time” used in ISO 11614.

3.14

opacimeter physical rise time

t_p

difference between the times when the raw k-signal reaches 10 % and 90 % of the full deviation when the light absorption coefficient (3.6) of the gas being measured is changed in less than 0,01 s

Note 1 to entry: The physical rise time of the partial-flow opacimeter (3.12) is defined with the sampling probe and transfer tube. Additional information on the physical rise time can be found in ISO 11614.

Note 2 to entry: The definition of the term “opacimeter physical rise time” used in this document is equal to the definition of the term “opacimeter physical response time” used in ISO 11614.

3.15

opacimeter electrical rise time

t_e

difference between the times when the instrument recorder output signal or display reaches 10 % and 90 % of full scale when the light source is interrupted or completely extinguished in less than 0,01 s

Note 1 to entry: Additional information on the electrical rise time can be found in ISO 11614.

Note 2 to entry: The definition of the term “opacimeter electrical rise time” used in this document is equal to the definition of the term “opacimeter electrical response time” used in ISO 11614.

3.16

filter rise time

t_F

filter rise time of the applied Bessel filter which is required to remove the high frequency distortions of the raw opacity (3.3) signal

Note 1 to entry: Additional information can be found in 9.2.

Note 2 to entry: The definition of the term “filter rise time” used in this document is equal to the definition of the term “filter response time” used in ISO 11614.