Gas supply unit for exhaust gas analysis unit for measuring exhaust gas from internal combustion engines

摘要

A gas supply unit for an exhaust gas analysis unit (10) for measuring exhaust gas of an internal combustion engine, a measuring device (18) for analyzing a sample gas, a calibration gas conduit (30; 32; 34), and a purge gas conduit (26) and a sample gas conduit (13), the calibration gas conduit (30; 32; 34), the purge gas conduit (26) and the sample gas conduit (13) being connected to a common connecting conduit (20). It is open so that a fluid connection can be made to the measuring device (18) via the connection conduit (20), the calibration gas conduit (30; 32; 34), the purge gas conduit (26). In addition, a shutoff valve (24, 28, 36, 38, 40) is provided in the sample gas conduit (13), and the sample gas is passed through these shutoff valves (24, 28, 36, 38, 40). Flow, calibration gas Measuring the exhaust gas of the internal combustion engine, which can selectively shut off or release the purge gas flow and is provided with a pump (16) for discharging the sample gas flow from the exhaust gas source (12) Gas supply units for exhaust gas analysis units are well known. In order to enable the exhaust gas analysis unit to operate with high accuracy even at very small flow rates and short response times, according to the invention, the sample gas conduit (13) is calibrated with the measuring device (18). The connection conduit (20) opens between the gas conduit (30; 32; 34) and between the measuring device (18) and the purge gas conduit (26), and the measuring device ( An outflow nozzle (42) is arranged at the end opposite to 18), and an outflow conduit (48) in which an outflow nozzle (50) and a shut-off valve (52) are arranged from the connection conduit (20). Propose that has branched.