Testing facilities have found fresh innovation to aid engineers in the development of tomorrow's cleaner cars

4 min read

Diesel gate is arguably one of the biggest engineering stories of the last few years. However, the story betrays the true nature of an industry redefining itself. Engineers have been battling impossible trade-offs and continue to undertake perhaps the biggest innovation drive ever seen by the sector as it struggles to become greener.

Beneath the scandal, numerous OEMs and innovative suppliers have busied themselves making genuine steps forward – meaningfully reducing tailpipe emissions. What many thought were technically mature technologies, have found renewed vigour, with innovations in engine and materials technology that will slash emissions to what, was once thought, impossible levels.

It is all driven from EU driven regulation that says OEMs must reduce tailpipe emissions to an average 95g of CO2 per km across their entire fleet of vehicles, or face pretty harsh financial penalties.

Regardless, it has sparked a transition in automotive technology to lightweight chassis, ultra-efficient internal combustion engines, highly complex hybrids and electric powertrains. Smarter computer controls are also used to constantly monitor various engine parameters and the external environment to alter engine modes and optimise performance.

As great as all this might be, it means those carrying out tests to develop and eventually certify vehicles are having to innovate at a similar pace to keep up. And more than that, they are having to anticipate regulation changes and carmaker trends so it can continue to reliably feedback data and be an active part of design refinement and vehicle development.

At the coalface is Millbrook Proving Ground, which has been putting developing cars through their paces since the 1970s. The company has recently invested several million pounds in the construction of a brand new state-of-the-art 4WD climatic emissions chassis dynamometer as part of a broader strategy to support an industry that is on the move.

“This is the biggest investment we’ve made, certainly this century,” explained chief executive of Millbrook Alex Burns. “This facility is something the market needs to help them develop and it is important, strategically, for the industry to aid the development tomorrow’s cleaner vehicles.

“EVs are increasingly coming in to the marketplace and we need to test those and accurately determine the electric energy consumption. But, equally, with regulations likely to broaden, emissions might need to be measured over a much wider operating temperature range, so you have a much better idea of real world performance. Ultimately, engineers and OEMs need to look at how their vehicles behave in a much wider spectrum of conditions.”

Real world data

The dynamometer is set in a climatic cell that works from -20 to +50°C. It reflects the wider climates that vehicle types are sold and used. The same vehicle is used in the blistering dessert heat of Abu Dhabi down to the freezing temperatures of Scandinavia. Manufacturers must show that the emissions and fuel efficiency don’t suddenly fall off a cliff when the air conditioning is on full blast.

Millbrook’s chief engineer of powertrain, Phil Stones, said: “We have developed a facility that will help develop vehicles for the real world by simulating real world conditions. We can simulate numerous drive cycles, at numerous temperatures, on the dynamometer in repeatable conditions. That aids and speeds up development.”

The trend in the industry is the demand for cost effective, faster testing. OEMs want to build fewer prototypes, develop vehicles more quickly, while reducing costs and time to market. Part of the allure, Millbrook claim, is that by having state-of-the-labs alongside its plethora of test tracks, allows data on real road conditions to be logged and instantly replicated on the dynamometer in controllable, repeatable, conditions.

“That is a huge attraction,” said Burns. “Being able to do track and lab work in the same location allows more efficient utilisation of prototypes.”

The dynamometer is housed within a climatic chamber that can be controlled within 1°C. Though not a wind tunnel, it accurately ‘speed tracks’ airflow on to the vehicle for engine cooling and to meet the same power requirement as if was going through air on a normal road.

Being able to recreate the exact conditions and drive cycle time after, means the facility is as repeatable as possible. This is vital, as it allows engineers to see what difference any changes to the design make, rather than wondering if any discrepancy is down to variability in the dynamometer or the chamber.

Future regulation

Part of the development of Millbrook’s facilities, more generally, is to keep up with – and anticipate – future trends in the industry. The dynamometer is perhaps its first move toward this and is capable of not just measuring carbon, but a number of other pollutants that will likely feature in air quality and emission standards going forward. These include the accurate measurement of Nitric Oxide (NO), Nitrogen Dioxide (NO2) and nitrogen oxide (N2O).

“Our latest generation of emission sampling systems can quantify both regulated and also unregulated particulates,” said Stones. “For example, within air quality, NO2 is not actually regulated, but from an air quality and global warming point of view it is an important factor. We do things that are not yet legally required, but we expect could be in the future. So we are looking at new pollutants that might come in, new drive cycles, new test methodology, and also establishing new benchmarks.”

There is also great deal of thought about designing and developing vehicles to cope better with climatic changes that induce parasitic losses, which again will affect efficiency and emissions. For example, a vehicle operating in a hot climate might have its air conditioning on all the time. So, increasing research to understand how this affects performance and then the development of air conditioning systems is likely to feature in the future. In addition, the performance of electric vehicles can fluctuate massively if the heater, and lights are on. The aim going forward is to reduce the variance caused principally by environmental conditions.

“We are having to innovate as much, and as quickly, as the industry,” concluded Burns. “Diesel gate has changed the landscape in terms of due diligence and how stringently things are looked at. Going forward, though, the test sector will see some significant changes and that means changes for us. We expect to be used more and more in the design and development of vehicles, rather than in the certification of a set of regulations.”