The apparatus for diluting exhaust gas according to an exemplary embodiment of the present invention includes a stagnant air forming unit configured to form stagnant air by decelerating a flow velocity of introduced exhaust gas, an ejector unit connected to a front end of the stagnant air forming unit and configured to discharge the exhaust gas to a front, and a dilution unit coupled to a front end of the ejector unit.

Methods and apparatus for an exhaust demand control system for measuring one or more contaminants at one or more exhaust locations within one or a plurality of exhaust ducts or plenums served by an exhaust fan system. Example systems and methods can include sensing the one or more contaminants within the one or more exhaust duct locations using a multipoint air sampling system having one or more sensors and comparing contaminant concentration measurements from the one or more of said exhaust duct or plenum locations against an action level to create a fan setback signal.

The aerosol diluting apparatus includes a first diluting unit to provide a first modified sample flow by combining an aerosol sample flow with a first diluting gas flow, an ejector unit to draw the first modified sample flow from the first diluting unit to the ejector unit and to provide a second modified sample flow by mixing a second dilution gas flow with the first modified sample flow, a control unit, and a control valve, wherein the control unit and the control valve are arranged to adjust flow rate of the second dilution gas flow according to an inlet pressure of the aerosol sample flow, so as to keep the dilution factor of the diluting apparatus substantially independent of the inlet pressure.

To provide an exhaust gas analysis apparatus that, without the need to greatly change the flow rate of diluted exhaust gas passing through a filter, can change the flow rate of exhaust gas in the diluted exhaust gas passing through the filter with good followability to reflect weighting, and accurately measure PM, the exhaust gas analysis apparatus is adapted to include: a collection part that collects particulate matter in sampling exhaust gas partially splitting from original exhaust gas or in the diluted exhaust gas resulting from diluting the sampling exhaust gas with diluent gas; and a split flow ratio control mechanism configured to, in accordance with a vehicle driving mode set in compliance with predetermined regulations, change a split flow ratio that is the ratio of the split flow rate of the sampling exhaust gas to the total flow rate of the original exhaust gas.

An exhaust gas dilution device according to an exemplary embodiment of the present invention includes a head part, ejector unit, a nozzle part, and a dilution part. The head part has a space part into which an exhaust gas flows and a through-hole formed through the center axis direction to be connected to the space part. The ejector unit is coupled to the head part and has a first discharge hole formed passing through the center axis direction to be connected to the through-hole and connected to a first inlet to which primary dilution air is supplied. The nozzle part is inserted into a first discharge hole through the through-hole and has a second discharge hole that penetrates in the center axis direction so that the exhaust gas flowed into the space part is sucked and ejected into the first discharge hole as the primary dilution air moves through the first discharge hole. The dilution part has a first flow path part into which a primary dilution gas, which is generated and discharged after the exhaust gas and the primary dilution air are mixed in the first discharge hole, flows, and a second flow path part connected to the first flow path part and guiding secondary dilution air to be mixed with the primary dilution gas, and generates a secondary dilution gas as the primary dilution gas and the secondary dilution air are mixed.

To uniformly dilute particulate matter contained in a sample gas, a diluter includes an inflow portion, a mixing portion, a discharge portion, a connection portion, and an introduction portion. The inflow portion allows a sample gas to flow in. The mixing portion has an inner diameter larger than that of the inflow portion, and mixes the sample gas with a dilution gas to generate a diluted sample gas. The discharge portion discharges the diluted sample gas. The connection portion has a first tapered part whose inner diameter increases from a side connected to the inflow portion toward a side connected to the mixing portion. The introduction portion introduces the dilution gas into an internal space from a position downstream of the connection between the first tapered part and the inflow portion.

An apparatus includes a sampling probe having a first portion and a second portion. The first portion is configured to penetrate inside a wall of a duct having an inner chamber that is configured to carry a gas stream containing particulate matter therethrough. The first portion is further configured to divert a sample of the, gas stream from the inner chamber of the duet to the second portion that extends from the wall of the duct opposite the inner chamber. The second portion of the sampling probe is configured to direct the sample of the gas stream in a first direction with a second direction corresponding to a direction of the gravitational force of the earth. A first ray corresponding to the first direction forms an angle β with a second ray corresponding to the second direction. The angle β is less than 90 degrees.

The aerosol diluting apparatus includes a first diluting unit to provide a first modified sample flow by combining an aerosol sample flow with a first diluting gas flow, an ejector unit to draw the first modified sample flow from the first diluting unit to the ejector unit and to provide a second modified sample flow by mixing a second dilution gas flow with the first modified sample flow, a control unit, and a control valve, wherein the control unit and the control valve are arranged to adjust flow rate of the second dilution gas flow according to an inlet pressure of the aerosol sample flow, so as to keep the dilution factor of the diluting apparatus substantially independent of the inlet pressure.

Methods and apparatus for an exhaust demand control system for measuring one or more contaminants at one or more exhaust locations within one or a plurality of exhaust ducts or plenums served by an exhaust fan system. Example systems and methods can include sensing the one or more contaminants within the one or more exhaust duct locations using a multipoint air sampling system having one or more sensors and comparing contaminant concentration measurements from the one or more of said exhaust duct or plenum locations against an action level to create a fan setback signal.

Methods and apparatus for an exhaust demand control system for measuring one or more contaminants at one or more exhaust locations within one or a plurality of exhaust ducts or plenums served by an exhaust fan system. Example systems and methods can include sensing the one or more contaminants within the one or more exhaust duct locations using a multipoint air sampling system having one or more sensors and comparing contaminant concentration measurements from the one or more of said exhaust duct or plenum locations against an action level to create a fan setback signal.