Abstract: The present invention provides for an acoustical volumetric measuring apparatus which utilizes a variable volume standard cavity. The variable volume standard cavity is preferably formed of a threaded two-piece cylinder which changes volume upon rotation of one piece relative to other. Further, the variable volume standard cavity is calibrated to externally display the current volume setting. This allows for simplified comparisons in determining the volume of an unknown cavity. The simplified comparisons allow for less expensive components to be utilized.

Abstract: A camera mount for a motor vehicle which always maintains the camera level with respect to the road surface regardless of vehicle rotations due to accelerational or gravitational forces to present a camera view typical of what a human would see looking out of the vehicle and responding to such vehicle rotations in the normal manner. The camera is supported on a pendulum suspended from a gimbal support on the vehicle sprung mass and constrained with spring and damping elements which are matched to the spring and damping elements of the vehicle suspension system to produce equal and opposite rotations of the pendulum for rotations of the vehicle.

Abstract: An internal combustion engine fuel consumption measurement system including an auxiliary fuel reservoir from which the engine fuel requirements are supplied and into which make-up fuel is provided to maintain a constant fuel volume and pressure. The make-up fuel quantity is measured as an indication of the fuel consumption of the internal combustion engine.