Dynamometer

Purpose

Today's automotive industry is subject to many regulations and requirements. Growing environmental demands and requirements for high performance, maximum energy efficiency. Most of the major car manufacturers and other renowned companies and institutions use dynamometers in their development, quality assurance and research of vehicle performance.

A dynamometer or "dyno" for short is a device used to measure power and torque produced by an engine. It is said to be created by the "Father of Computing" Charles Babbage.

In general, dynamometers are useful in the development and refinement of modern day engine technology. The concept is to use a dyno to measure and compare power transfer at different points on a vehicle, thus allowing the engine or drive train to be modified to get more efficient power transfer.

For example, if an engine dyno shows that a particular engine achieves 400 N·m (300 lbf·ft) of torque, and a chassis dynamo shows only 350 N·m (260 lbf·ft), one would know to look to the drive train for the major improvements.

Dynamometers are typically very expensive pieces of equipment, reserved for certain fields that rely on them for a particular purpose.

Types

There are two types of dynos:

• Engine dynamometer
  This type is normally fixed in a special frame that allows engines to be mounted on to it and can be directly coupled to the engine flywheel. An engine dynamometer measures power and torque directly from the engine's crankshaft (or flywheel), when the engine is removed from the vehicle. These dynos do not account for power losses in the drive train, such as the gearbox, transmission or differential etc.
• Chassis dynamometer
  This type is sometimes known as a "rolling road" and the vehicle can be driven onto the rollers and then fixed to the ground with special anchors to ensure that the vehicle does not jump off of the rollers during testing. A chassis dynamometer measures power from the engine through the wheels. The vehicle is driven in gear which turns the rollers and the output is measured. These dynos can be fixed or portable.

In both cases the objective is to be able to measure power and torque output.

General workings

The dynamometer applies various loads on the engine and measures the engine's ability to move the load. Modern dynamometers are normally connected to a computer which uses math to calculate the output of the engine. The engine is run from idle to its maximum RPM and the output is measured and plotted on a graph. Nearly all aspects of engine operation are measured during a dyno run.

Source: CDX Global & Wikipedia - en.wikipedia.org