Power measurement turns to energy efficiency

Datum Electronics has a portfolio of products capable of measuring power on a vehicle or on active plant, ranging from simple data logging systems to trials and permanent fit torque and power meters.

Energy efficiency has traditionally been a method that determines maximum power and performance of the latest car or engine measured against speed.

The term energy efficient in today's technologically focused and modern world focuses on much more than just speed and power, and looks to measure performance throughout the speed spectrum.

The idea that performance of the latest car should be measured in terms of the maximum power that it could give at whatever speed "180bhp at 3500rev/min".

Although the focus may have switched from maximum power and speed to performance efficiency, similar thinking should still apply.

Every power plant, whether it is applied to a car, lorry, rolling mill or a ship will have a power curve related to its rotational speed.

The curve will show that the motor and transmission system will output with the greatest efficiency at a certain speed.

Most engine manufacturers will have this figure from their test and design data.

To establish this curve; the manufacture will use a design model to create this theoretical analysis and then test the engine on a test rig measuring the engine output in terms of speed and torque, and its input in terms of fuel and set-up.

These performance tests and analysis are applied in ideal conditions with a brand new engine.

Theoretical analysis could typically estimate the most power efficient running speed from the curve and drive the vehicle at the most efficient speed.

This would be a very crude use of the data but it may help to determine the greatest efficiency and performance.

The assumption does not take into account the various conditions of engine performance in actual driving conditions; load on the vehicle, gradient of the road, wind conditions etc.

The engine performance in a test environment is likely to be far different from actual performance, for example if an HGV is driving up hill against the wind with a full load.

Other factors may also include age of the engine, vehicle servicing and general wear and tear.

Is the engine performing as well as it should?.

It would be very useful to know what is happening on the vehicle during actual driving conditions, the same way the test engineers do within a test environment.

It would be useful to use this information to control the vehicle speed, maintaining energy efficiency.

By running through an average week's cycle it is possible to establish the most efficient running mode for most vehicle or power plant.

The control input you would need to monitor fuel/power input, the effective power output and the result (miles travelled).

All of these measurements are now possible and more importantly affordable.

Most vehicles are fitted with a fuel flow monitor and some form of tachograph input.

Simple and robust shaft power meters are now available and have the computing power to collect and analyse the data and the engine control units exist to provide the control.

Datum Electronics has the expertise to gather and analyse the data required.

From the data captured an assessment can be made of the potential fuel savings by introducing a new control regime.

Typical savings between 1 and 9% have been seen on similar systems.

Additional benefits have also been derived from such studies leading to more cost effective planning of drive system maintenance.

Longer term benefits from an understanding of the actual operating performance will arise by having real data to feedback to future studies and for collaboration with other suppliers of plant and fuel.

In many cases, such studies will attract European funding that is targeted at meeting government targets in accordance with both emission and efficiency levels.

Datum Electronics has a portfolio of products capable of measuring power on a vehicle or on active plant.

Ranging from simple data logging systems to trials and permanent fit torque and power meters, the company also provides test torque transducers used by the power plant and transmission suppliers to evaluate their equipment.

Unlike many consultancy teams Datum has the unique ability to call on its 16 years of experience working in the heavy vehicle and rotary machinery markets.

This includes the planning and design of various analysis and tests, implementing practical on-vehicle solutions meeting the needs of the customer.

The company has provided over 60,000 measurement systems to vehicle customers including Caterpillar, John Deere, Claas, MOD, JCB, Cosworth and Jaguar.

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