Abstract: An air turbine apparatus for use with a combustion engine either as a muffler or as an air intake device is comprised of a housing defining an expansion chamber and an airfoil positioned within the housing. The airfoil includes a central aperture extending longitudinally therethrough that is in fluid communication with both the inlet and the outlet of the housing. The airfoil is configured to allow gases flowing through the inlet to flow between the outer edge of the airfoil and the housing and through the aperture of the airfoil. In addition, the air traveling through the housing is caused to spin as it travels through the housing. This rotational flow increased the rate of flow of gases through the air turbine device. A chop core is provided between the airfoil and the outlet of the housing to encourage turbulent flow of gases without restricting flow to produce a muffling effect and thus a dampening of noise from the combustion engine.

Abstract: A visual tire cap pressure gauge which comprises a cap member. A structure within the cap member is for securing the cap member to a valve stem on a tire in a motor vehicle. A lens is mounted in a top end of the cap member. An assembly within the cap member is for visually indicating when air pressure within the tire drops below a set point, so as to enable a person at a glance to tell if the tire needs more air.