Up to 80 vehicles go through the exhaust emissions laboratory at Millbrook Proving Ground each week.

Running 24 hours a day, delivering a consistent and accurate testing process is a key responsibility of senior engineer Anthony Sale.

Focus on testing process

Fuel use and CO2 emissions are high on the agenda for fleet operators.

The testing process and the figures themselves become a focal point in a new car’s development.

The New European Driving Cycle (NEDC) is the testing process used to assess the emission levels and official mpg figures of new cars.

Manufacturers are legally obliged to carry out the test on the worst case scenario variant of each model in their current range, with some manufacturers testing every single variant. This can be carried out only at approved laboratories.

To meet regulations and ensure consistency, Millbrook’s emissions laboratory is calibrated every week.

This includes checking the sampling system for leaks, assessing the dynamometers for changes in rotational resistance and conducting validation tests on known test vehicles each week.

“Making sure the procedures we follow are exactly the same every single day and repeating tests in exactly the same conditions can be a challenge,” says Sale.

“My role involves checking that all tests we carry out meet the current legislation, analysing complex data and explaining the results to clients.”

The NEDC cycle

The NEDC test has existed for around 30 years and although it is not the most representative of real-world driving (all technology and built-in equipment such as air conditioning is turned off), it is able to act as a benchmark for all vehicles.

On arrival at Millbrook, a vehicle will go into the emissions laboratory where initial checks will be carried out to confirm it is in good condition.

The car or van is driven over a pre-conditioning cycle and then parked overnight in set humidity conditions and at 23°C.

The following morning, the engineers check that the oil and water are all within 2°C of the lab ambient temperature.

The vehicle is loaded on to a chassis dyno and run over the NEDC cycle.

“The NEDC test is a defined cycle which includes idling periods, acceleration and braking. It is all carried out inside a controlled laboratory environment with fixed temperature and no wind or hills,” says Sale.