In order to allow an analyzer to be calibrated or a sampling channel to be purged without removing a sampling probe from a sampling location, provided are a sampling channel through which an exhaust gas from an internal combustion engine flows, an analyzer that is connected to the sampling channel and analyzes the exhaust gas, a diluter provided upstream of the analyzer in the sampling channel, a recirculated channel that branches from a branch point set between the analyzer and the diluter in the sampling channel and joins the diluter, a pump that is provided in the recirculated channel and guides part of the exhaust gas from the branch point to the diluter, an additional channel that is connected to the recirculated channel or the sampling channel and through which a calibration gas or a purge gas flows, and an opening and closing mechanism provided in the additional channel.

A control cabinet arrangement for an exhaust gas measurement device. The control cabinet arrangement includes a first control cabinet which delimits a first interior space and a second control cabinet which delimits a second interior space. A first heat-generating component of the exhaust emission measurement device is arranged in the first interior space. A second component of the exhaust emission measurement device is arranged in the second interior space. At least one fluidic connection connects the first interior space and the second interior space. The second component is heatable by an air flow flowing between the first interior space and the second interior space.

A pressure reduction system and methods therefore that include features for reducing the pressure of a high pressure aerosol to ambient pressure without significantly changing the characteristics of the aerosol are provided. In this manner, the non-volatile particulate matter concentration in a sample stream obtained from the aerosol stream at ambient pressure is representative of the non-volatile particulate matter concentration that was present in the aerosol stream at high pressure prior to the pressure reduction.

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.

A gas analysis system for a vehicle includes a measurement chamber that includes at least one sensor configured for measuring substances in exhalations from vehicle occupants and/or the ambient air in a vehicle interior. The gas analysis system may also include at least one fan placed at a discharge opening for the system and designed to convey air through the measurement chamber, at least one filter located at an intake opening in the system and designed to prevent particles from contaminating the system; at least one first check valve, located between the measurement chamber and the fan, and designed to block a return-flow of the air out of the measurement chamber and/or ambient air from the vehicle interior into the measurement chamber, and a control unit, designed to regulate and/or control the conveyance of air through the measurement chamber.

A laser absorption spectroscopy exhaust gas sensor includes an optical cell with porous walls having pores with a mean diameter in the range of 0.1 nm to 1 mm; gold mirrors within the optical cell positioned to support a multi-pass optical path within the optical cell; an active heating element adapted to heat the optical cell to prevent condensation; a laser adapted to generate a laser beam; an optical detector adapted to detect a returning laser beam; and a processor for controlling the laser and the active heating element and for analyzing signals from the optical detector to identify a gas in the optical cell.

To measure an internal state of an engine, for example, the engine oil consumption conveniently and correctly, an inspection apparatus of the present invention for inspecting the internal state of the engine by using an exhaust gas of the engine including engine oil includes a data storage unit that stores content information about a plurality of elements contained in the engine oil, a data acceptance unit that accepts analysis information about a plurality of elements contained in the exhaust gas, and an inspection unit that compares the content information about the engine oil with the analysis information to inspect the internal state of the engine.

Various embodiments include an exemplary apparatus and method for insitu calibration of multiple flow-sensing devices within a dilution system. In one example, a calibration and dilution system includes a first mass-flow device to serve as a global reference, a second mass-flow device configured to be coupled to and provide a supply of clean gas to a primary diluter, and a third mass-flow device configured to be coupled to and provide a supply of clean gas to a secondary diluter, where the diluters are pneumatically coupled to one another through a gas-supply line. Multiple valves are coupled to at least the mass-flow devices and the diluters. The calibration and dilution system is arranged so that the mass-flow controllers can be calibrated in-situ without having to remove any of the mass-flow controllers from the calibration and dilution system. Other apparatuses, designs, and methods are disclosed.

An exhaust gas analysis device analyzes exhaust gas generated when fuel is combusted. This exhaust gas analysis device includes a first analyzer that measures a concentration of a component to be measured in the exhaust gas, a second analyzer that measures a concentration of CO.sub.2 in the exhaust gas, a storage portion that stores a hydrogen/carbon ratio, which is a ratio between hydrogen and carbon composing the fuel, or an input receiving portion that receives an input of the hydrogen/carbon ratio, a moisture concentration estimating portion that, based on the measured CO.sub.2 concentration and on the hydrogen/carbon ratio of the fuel, estimates a concentration of moisture in the exhaust gas, and a correcting portion that, based on the estimated moisture concentration, corrects the measured concentration of the component to be measured.

A gas analysis device that comprises a first flow channel through which a sample gas flows, a first analyzer that is arranged in the first flow channel and that performs wet-measurement of a total hydrocarbon concentration in the sample gas, a second flow channel through which the sample gas flows, a non-methane cutter that is arranged in the second flow channel and that removes a hydrocarbon component other than methane in the sample gas, a second analyzer that is arranged downstream of the non-methane cutter in the second flow channel and that performs dry-measurement of a concentration of methane in the sample gas, and a calculation section that calculates a concentration of the hydrocarbon component other than methane in the sample gas using the total hydrocarbon concentration obtained by the first analyzer and a corrected concentration of methane, which is a moisture corrected methane concentration, obtained by the second analyzer.