A dynamometer, often called a “dyno,” is a sophisticated instrument used to precisely measure the mechanical force, power, and torque produced by an engine. Charles Babbage, the inventor of the dynamometer, is also celebrated as the “Father of Computing.”
There are two primary types of dynamometers: engine dynos and chassis dynos.
An engine dynamometer directly connects to the engine, typically at the crankshaft or flywheel, when the engine is removed from the vehicle. It measures the engine’s raw power output, without factoring in power losses within the drivetrain components like the gearbox, transmission, or differential.
A chassis dynamometer, on the other hand, measures power output through the vehicle’s wheels. The vehicle is secured on rollers, and the dyno measures the power delivered to those rollers. Chassis dynos can be either fixed in a permanent location or portable for on-site testing.
The dynamometer works by applying controlled loads to the engine and meticulously measuring the engine’s ability to overcome these loads. This data is fed into a computer, which uses complex mathematical calculations to determine the engine’s performance characteristics. During a dyno run, the engine is tested across its entire RPM range, from idle to maximum speed. The results are displayed graphically, providing a detailed picture of the engine’s performance. Virtually every aspect of the engine’s operation can be evaluated during a dyno test.
Dynamometers play a crucial role in the development and refinement of modern engine technology. By measuring and comparing power transfer at various points in the vehicle, engineers can identify areas for improvement in both the engine and the drivetrain. For instance, if an engine dyno indicates 400 N·m (300 lbf·ft) of torque, but a chassis dyno reveals only 350 N·m (260 lbf·ft) at the wheels, it signifies a power loss within the drivetrain. This prompts inspection and optimization of the drivetrain to maximize efficiency.
While dynamometers are invaluable diagnostic tools, their high cost often limits their availability to specialized facilities and automotive professionals.