Millbrook VTEC: Testing the future of vehicle propulsion

Britain’s aggressive carbon reduction ambitions put the onus on publicly funded industries to lead by example. With its VTEC facilities, Millbrook tests propulsion systems of new vehicle technologies to aid in those ambitions

Britain’s zero carbon targets won’t be achieved without dedicated facilities to help manufacturers and regulators meet those industry standards.

Millbrook’s confidential and secure proving ground boasts a broad portfolio of test facilities to help vehicle manufacturers perfect and deliver the green demands of the future.

Since there is little that can be done about the aerodynamics of a coach or bus – its shape dictated almost wholly by function and not generally conducive to change – it therefore lies with companies like Millbrook to test the powertrains that deliver the benefits.

Millbrook supports the Clean Vehicle Retrofit Accreditation Scheme (CVRAS) testing, its primary focus being on emissions. It expects, however, the market to change rapidly, and is ready for it – which is why Millbrook is investing in a brand-new variable temperature emissions chamber (VTEC).

Emissions testing of a double-deck bus at Millbrook

Emissions testing at Millbrook

Since 1996, Millbrook has tested vehicles in its VTEC chamber using a light- and heavy-duty chassis dynamometer.

“Historically, data was logged on an old Routemaster and that’s when physical bus testing started,” says Phil Stones, Chief Engineer Propulsion at Millbrook. “Engines that go in buses are already certified on an engine dyno, but emissions come from vehicles and the respective duty cycle, and therefore emissions can be very different to those on the approved engine cycle.”

To date, Millbrook says the facility has helped the industry to develop an understanding of emissions in its vehicles and prompted better pseudo-regulations to be created – driving the sector to improve. It’s done very well – regulators use it, and petrochemical companies use it to develop fuels.

The new VTEC, which will be operational next year, will have a 60 tonnes dynamometer with four-wheel drive capability – another preparation for the future.

“Vehicles are getting much cleverer,” Phil ventures. “To get them to work on two-wheel drive correctly is harder and harder.”

The new VTEC will have a broader inertia range and dynamic gradient simulations, allowing vehicles to be tested where gradient has a large influence on fuel consumption. It will allow manufacturers to see how a vehicle compares, say, on flat London summertime roads compared to the inclines of Sheffield in winter.

Crucially, the new VTEC will heavily encompass facilities for electric and hydrogen vehicle testing.

“We are investing significantly with the latest advanced emissions systems,” Phil says. “Our current VTEC doesn’t have full safety systems for hydrogen, but the new one will be catering for that.”

While hydrogen is a potential avenue for the coach and bus industry, it’s down to the upstream to decarbonize the well-to-tank aspect. All Millbrook can do – and is doing – is to support those vehicles to use that energy source efficiently in the future.

Leading by example

Buses continue to have an interesting part to play in the story of emission reduction. The question, after all, exists: If the government can’t sort out reduction of emissions in public transportation, why, then, should the individual?

Coaches and buses have always been a burden on air quality. They have a large part to play in how the country moves forward in its net zero emissions goals. Millbrook is positive. There are challenges – such as a shrinking market due to current economics. But the firm is engaging with its customers as to what they want to be supported.

To some level that shrinking market has been compensated by CVRAS, but in other areas it has had an impact. Stagnant bus development means there has been a reduction is vehicle testing. That creates knock on effects – if development stops, the OEMs will not have anyone to develop for in future. In the long term, that can halt progress and create a skills shortage.

Under pressure

But how much pressure can the government put on the bus manufacturers to improve things? It has to be remembered that if buses don’t make enough money, operators will reduce routes and purchase fewer vehicles. In that scenario, OEMs won’t develop better buses, which can reduce progress and have a negative overall impact on public transport.

And now, as buses improve, coaches will come into the frame for air quality. The destination for a coach is often a city, even if most of its mileage isn’t. Proportionally, as other vehicles become cleaner, coaches will become a greater burden.

Strictly, this will be of more concern for the older fleets, Phil says, and for retrofit systems and suppliers. Such progression is natural, as once the buses are finished with, those retrofit suppliers won’t otherwise have a business. But the different operating regime and financial structure to buses – less bound by councils providing the roots – will prove interesting.

The UK’s commitment to net zero emissions by 2050 means the industry is under pressure. The air quality debate is likely to push biofuels out of the picture, so hydrogen and electric are safe assumptions for long term goals – assuming there will be money to allow for their development, and the well-to-tank aspect is decarbonised. The price, of course, has to come down considerably – and, according to Millbrook, will likely be dictated by how much the government wants to incentivise them.