Andy Eastlake, Head of Laboratories at the U.K.’s Millbrook Proving Ground, wants to see greater reality introduced for environmental test regimes. “The automotive landscape is changing fast with the introduction of hybrid and, soon, electric vehicles, but as it does, it is imperative that we deliver test programs that are relevant to actual scenarios on our roads, that results are appropriate to the end user.”
Many ambient emissions models use results from legislative test cycles not those conducted in the real world, he said. “They are fed from theoretical numbers, and such models don’t then correlate with the true emissions that end up being measured in our cities.”
And he emphasized that although the sharpest environmental, political, and financial focus continues to be on CO2 emissions, another “huge challenge” was to meet nitrogen oxides (NOx) and particulate (PM) air quality emissions targets. “It is imperative that across the industry, the tests we carry out for research should be far more representative of what happens in the real world so that decisions made on issues such as low emissions zones are based upon true figures.”
He singled out emerging hybrid models for particular attention, stating that a hybrid vehicle might work very effectively in a stop-start environment but not so well in a motorway-type scenario. “So, we need to make sure the tests are looking at both sides of the equation in order to come up with accurate data.”
Hybrid testing brought added complications, he said. These include the necessity of meeting legislation already in place that requires a hybrid vehicle to be tested at various levels of battery charge. “This means that vehicles may have to be tested several times compared to once for a conventional vehicle, resulting in an increased cost process. Our task at Millbrook is to maximize the output from every test and to make commercial sense of every technological improvement.”
Another difficult area is measuring emissions from small-engined hybrid vehicles stopping and starting in traffic. It is a complex test program but one where the industry is starting to deliver cutting-edge techniques to help the process, stated Eastlake.
Measuring the amount of electric energy available to power a vehicle is also extremely important but requires sophisticated equipment to understand highly transient current flows in the electrical system. Safety is also critical for the area of high energy electric systems’ testing.
Battery testing of hybrid and, increasingly, electric vehicles, is also challenging, with range the biggest issue. Batteries are expensive, so there is likely to be an optimum commercial point where a manufacturer can see that typically 80% of vehicle owners will cover 80 km (50 mi) in a specific period in a certain type of vehicle. So the technology is optimized and the battery sized to deliver on that likely range requirement.
“But since very few customers would buy a vehicle with only that range, the Extended Range Electric Vehicle concept is becoming ever more popular,” states Eastlake. “As a result, the concerns over short electric range [range anxiety] are removed by incorporating a small, efficient engine to give similar overall range to current conventional vehicles. Critically, the electric range can be dramatically influenced by gradients and how a vehicle is driven—so both need, where possible, to be taken into account when testing and developing. And that means real-world simulations will invariably offer more accurate feedback.”
Eastlake approaches these testing challenges with enthusiasm. As an industry, he said, it’s an exciting and very interesting time, with the advance of vehicle technology, the need to resolve all test issues, changing legislation, and the embracing of new equipment such as four-wheel drive wheel dynamometers to measure wheel hub motors used in conjunction with energy capture and regenerative braking systems.
Education plays a vital role in the move toward comprehensive testing of hybrid vehicles, and the auto industry has a significant number of highly talented engineers that need training in relevant electronics systems, said Eastlake.
There is also a need to attract more high-quality electrical and electronic engineers into the automotive test and development sector. “The driving of hybrid and electric vehicles offers up a whole new raft of opportunities, challenges, and avenues. Across the arena, we’re improving efficiency, but we can’t get away from the fact that the driver is still one of the biggest factors in vehicle efficiency. The transition to hybrid vehicles will be challenging for all—and we are working hard to make sure that the testing of vehicles keeps up with new technology and that it reflects reality and not just legislative test cycles.”