Dynamometers Industry Information

Dynamometers, also called "dynos," are machines used to measure the power of an engine. More specifically, the torque of an engine is determined by a complex system of absorption and reaction. Dynamometer manufacturers construct their products using basic components: frame, engine mounts, absorption unit, which is usually some sort of roller or drum, heat exchanger and torque measuring device. Water or oil brakes are needed for certain types of dynamometers to provide proper resistance and absorption. Engines are hooked up to the dynamometers in various ways and then run. The dynamometers simulate actual conditions by allowing the engine to run at long intervals and at peak levels without ever having a vehicle in motion or an operator inside a vehicle.

The commercial auto industry relies on dynamometer manufacturers in the development and testing of their vehicle engines. Those who specialize in the rebuilding and customization of engines also use dynamometers extensively. Makers and designers of high-performance vehicles, such as race cars and speed bikes, use dynamometers for similar reasons as those of the commercial auto industry and as part of the recalibration process of an engine, which has been used in race environments. Dynamometers are also sometimes used in the testing of other types of internal combustion engines used for industrial purposes, such as engines in water pumps and large earth-moving tractors.

Most modern dynamometers are computer controlled, and allow the operator to select the points and range of speeds through which an engine's torque is measured. The operator then opens the throttle of the engine and the dynamometers react with an appropriate amount of load to maintain the chosen condition. The horsepower and other measurements are read out directly to a real time gauge and from this the torque is usually calculated. Analog gauges are still used to determine the torque of an engine, but operators of dynamometers need some knowledge of physics to come up with the final reading.

When looking at dynamometer manufacturers, consider important performance specifications: torque capacity, maximum rotary speed and power absorption. For chassis dynamometers, keep in mind the maximum linear speed on chassis style. The torque capacity is the highest continuous torque transmission for which the shaft is designed. The maximum rotary speed is the highest rated rotational speed under load. The highest rotational power at which dynamometers can be operated while still running within specifications is the maximum rotational speed. This speed is often regulated by the braking technology and configuration. In terms of chassis-style dynamometers, the highest linear speed of the vehicle under test is rendered in miles per hour.