Dynamic and Climatic Testing For Future Transport

| Environmental Testing

Millbrook VTEC 2 facility has a large climatic chamber and 4WD chassis dynamometer

Jonathan Newell finds out about the new VTEC facility at Millbrook in Bedfordshire as the test bed for future heavy transport.

The shift away from the internal combustion engine towards Battery Electric propulsion and hydrogen fuel cell technology doesn’t just affect light passenger transport but is also having a profound effect on the way the future of larger vehicles, including public transport, military machinery and large off-road construction and agricultural vehicles.

In order to help in the development of powertrains for such vehicles as well as achieving certification against emissions and other standards, the UK’s UTAC CERAM Millbrook proving ground and vehicle engineering facility in Bedfordshire has invested in a new facility comprising a large climatic chamber with multi-axle dynamometer for testing larger multiple wheel drive vehicles.

The VTEC 2 facility (Variable Temperature Emissions Chamber) is currently running alongside the existing VTEC 1 chamber, which is continuing to carry out tests that have already been commissioned and scheduled in. How long the two chambers will continue to be used together will depend on decision made at Millbrook later this year.

To find out more about the new facility, I spoke to John Proctor, the Technical and Special Projects Director at Millbrook. According to Proctor, the original VTEC chamber has been in operation for over 20 years and has carried out nearly 20,000 tests to evaluate emissions in different climatic conditions and down to temperatures as low as -25°C.

The chamber was built for both passenger cars and heavy duty vehicles and supports various national and regional clean air initiatives. However, as technology moves on and drivetrains become more complex, there became a need to upgrade the 2WD dynamometer facility.

VTEC 2 Capabilities

VTEC 2 is a heavy duty climatic emissions chassis dynamometer facility for TfL emissions, CVRAS, real driving emissions simulation, development and product benchmarking testing, suitable for use by diesel, petrol, LPG, CNG, electric and hydrogen vehicles with up to 60 tonnes of inertia.

Climatically controlled from -20°C to +50°C, the large 25m x 7m x 6m chamber is designed to test 2WD, 4WD or tri-axle trucks, buses and off-highway vehicles for emissions, fuel and lubricant performance and climatic performance.

Amongst its capabilities are the ability to test electric vehicles to determine energy consumption, range and energy efficiency and to test vehicles using alternative fuels such as hydrogen, LNG and CNG for range, emissions and fuel consumption over a drive cycle.

Asked why Millbrook didn’t upgrade the existing facility, Proctor explained that it wasn’t enough just to do a simple upgrade since it was necessary to provide it with a multi-axle dynamometer to cope with the latest large hybrid and battery electric buses, which are equipped with regenerative braking.

“The new dynamometer also has Increased inertia capabilities taking it up to 45 tonne or even 60 tone with load simulation. The current dyno can absorb 200kW, but new vehicles can produce more power so the new one has been designed to absorb up to 1GW, which is enough to satisfy foreseeable future requirements,” he explains.

Future Proofing

This need to predict the future is one of the key challenges facing the automotive industry as a whole. As Proctor explains, currently the industry is tending to be focused on power trains but vehicle systems are becoming increasingly integrated and he believes that the future challenges lie in connectivity and integration.

In his view, there won’t be a single technology that characterises future transport needs but a mix of technologies that suit different applications, such as hydrogen fuel cells and plug-in vehicles. For this reason, it’s important for facilities such as those at Millbrook remain both technology and application agnostic.

He also sees testing regimes becoming more integrated. Batteries, battery abuse, crash safety performance and power train technology are all linked in the chain of testing and so the proving ground has capabilities and expertise in all these areas and they’re continuing to develop.

Diverse Applications

There are a number of key applications for the VTEC 2 test facility and these each have their unique challenges.

Power train design and development engineers will use the chamber and dynamometer to understand the effects of drive train design on emissions and performance under different loads and climatic conditions.

“Turnaround times for such tests are very quick so development engineering activities become the bottleneck. For this reason, Millbrook provides its drivetrain development clients with support on data analytics and thereby extra capabilities in the market. Doing this helps to satisfy the need for improving development cycle times,” Proctor tells me.

Hydrogen fuelled vehicles are relatively new and these have hydrogen fuel cell and energy management systems which have integration challenges in terms of diagnostics, calibration etc. This is an important new use of the chamber and dynamometer for the design and development of complex power trains. For the fuel cell there’s a need for looking into the robustness of such systems in different climatic conditions. The design specification of VTEC 2 included the provision for making it “hydrogen safe” to detect and mitigate any leaks during the test processes.

The petrochemical industry is also predicted to be a heavy user of the facility as suppliers of lubricants and fuel additives research the effects of different climatic conditions on lubricant effectiveness and emissions reduction resulting from the use of additives. To achieve this, the industry needs high levels of very detailed data and high levels of repeatability in the results.

Emissions testing for heavy duty Electric Vehicle manufacturers have to cover an enormous range of different operating conditions resulting from various driving cycles in different climatic conditions. This has to be supplied as fast as possible to enable development teams to produce satisfactory results that will enable them to achieve certification.


We discussed the capacity requirements for the new facility and Proctor explained that hydrogen vehicle testing and battery heavy duty vehicle integration testing plus the requirements of the petrochemical industry are the main capacity drivers currently with more requirement in the future for fuel cell testing for bus and niche vehicles.

Millbrook currently has the two VTEC facilities available with the future of VTEC 1 coming under review at a later stage.

Availability of suitably qualified and experienced engineers is something Millbrook takes very seriously so that as the complexity of the automotive industry increases, shortages of experienced engineers in hydrogen fuel cells, EVs, connectivity etc won’t start to bite. Millbrook has been investing in graduate and undergraduate schemes as well as developing and investing in its existing staff to fulfil future needs.

“The supply of new engineers needs to reflect the changes happening in the industry. We still need good strong basic engineering skills plus specialist knowledge in diagnostics, data analysis and new technologies. We need a combination of all of these,” Proctor concludes.

Environmental Testing At Millbrook

As Proctor explained, an integrated and holistic approach to environmental testing is necessary to meet the future needs of the transport industry.

At Millbrook, there are the facilities at the Bedfordshire proving grounds as well as a large chassis dynamometer for commercial vehicles to evaluate Noise, Vibration and Harshness (NVH) plus the “Test World” cold climate snow and ice proving grounds in Finland.

I recently spoke to Jukka Antila, Technical Director, and Andy Beach, Business Development Director at Test World about the latest changes that have taken place there.

According to Antila, the latest addition to the organisation’s armoury of test equipment is the ASTM Traction truck, designed for testing tyres according to the ASTM 1805 standard for single wheel driving traction in a straight line on snow-covered surfaces.

Those snow covered surfaces are assured at the Ivalo facility, where testing can take place in the summer on the large indoor ice and snow covered tracks. Such year-round access enables tyre and power train development activities to continue without relying on seasonal availability.

When asked about how these facilities are used, Beach explained that tyre manufacturers can either use the facilities themselves or provide test specifications to Test World. In addition to tyres, the facilities also provide an opportunity to perform real world climatic evaluations.

“We can assess how fluids, lubricants etc react to severe climatic conditions in objective and subjective tests,” he says.

Engineers are able to validate simulation operations in chambers and rolling roads, for example testing that regenerative braking on EVs doesn’t lock the wheels when lifting the throttle. According to Beach, more borderline cases can be tested using simulation and then verified if necessary on test tracks.

“Engineers can map out a real world test to validate the key parts of their simulation results,” he concludes.

Jonathan Newell
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