Line selector for sampling gas in IC engine - has motor-driven piston in cylinder to select line connecting to gas analyser

摘要

Sampling lines from an IC engine enter a cylinder in which a selector piston travels. The piston has an enlarged section with sealing rings at either end, and in which a diametral hole connects with annular slots. This hole connects with a longitudinal hole in the piston which allows the sample gas to pass into a chamber and via a pipe to a gas analyser. The piston assembly is moved by a screw and nut assembly attached to the piston by a radial shaft. The operator applies power to an electric motor to cause it to step to displace the screw and nut. This causes the piston to move to the selected sample line.