Eliminating Exhaust-gas Leaks
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erliE Four Wheel Drive Auto Co.,
Clintonville, Wis., U.S.A., has recently ,devoted considerable attention to the .queStion' of preventing exhaustgee leaks in the drivers' eabs of lorries. Tests have shown one or more Of the following factors to be the cause of the presence of excessiVe quantifies of gas in the cab:A leak in the exhaust system; low combustion efficiency; trailing.eddy currents, and openings in the floorboards or other portions of the
o dY. A special instrument has been devised to carry out the 'tests, which have shown that leaks can be prevented by the use of a three-piece manifold with expansion joints between the middle and two end sections. The joints compensate for the differences in expansion between the manifold and cylinder block, which occur alternately each time the engine beats up and eciolS off. The compensation for the expansion differences lessens the high stresses built up in the manifold and manifold gaskets, which cause them to warp or crack, thus allowing exhaust gases to leak out, A change has also been made in the joint between the manifold and the exhaust pipe to eliminate gas leaks at this point.
The next preventive measure is a thorough check and adjustment of the ignition and carburation systems in order to attain proper combustion efficiency, thereby reducing the percentage of carbon monoxide in the exhaust gases. The third step is the use of gas-tight cabs for the drivers and the thorough checking of each with a detector to ascertain that there is no point at which gas can enter.