Abstract: A galvanic exhaust gas sensor having a solid electrolyte disc having a porous electrode thereon for detecting oxygen partial pressure in an exhaust gas stream varying in its flow and composition and having a shield protecting the porous electrode from direct impingement of exhaust gas stream. The shield includes means for accelerating exhaust gas from across the disc face at exhaust gas stream velocities and pressures below a preselected level and for maintaining said flow more constant at exhaust gas stream velocities and pressures above the preselected level, effective to more accurately sense variations in oxygen content of the exhaust gas stream at a porous electrode.

Abstract: The drawings illustrate a viscous fluid coupling including driven means comprising a housing with a front cover member having cooling fins thereon and rotatably mounted on an engine-driven drive shaft, driving means including a drive plate mounted on the drive shaft within the housing, opposed shear surfaces formed on the drive plate and the adjacent surface of the housing disposed in close face-to-face and spaced relationship, and a viscous fluid in the housing for creating fluid drive coupling of the housing and the drive plate. The improvement comprises a sleeve-type hub coaxial with the cover member and spaced axially from the usual cover-mounted bimetal temperature sensor and a plurality of circumferentially spaced, radially oriented, canted fan blades having their inner ends attached to the hub and having at least their outer ends attached to the cover member inwardly of the outer periphery thereof for aiding in the cooling of the viscous fluid.