Efficiency measurements on hypoid gears used in car axle drives

The author of this article describes a way of accurately measuring the efficiency of car axle drives.

Demands are being continually made on motor vehicle manufacturers to make savings in fuel economy through improvements in vehicle efficiency. But the state has been reached where improvements in efficiency are now very difficult to obtain. However, due to the large number of vehicles on the road even a small increase in vehicle efficiency would be a desirable achievement in terms of reduced overall energy consumption.
A problem arises though in obtaining accurate measurements of the efficiency of mechanical drives in vehicles.