This semester, the AAPS cohort have been working on a group project to evaluate the third generation Toyota Prius plug-in hybrid. We were given the opportunity to take over the chassis dynamo-meter for a week to put the Prius through its paces. The chassis dynamo-meter ('dyno') is a rolling road where you drive a vehicle while measuring the emissions and performance of the vehicle in various conditions.
The AAPS cohort is comprised of an eclectic mix of mechanical/automotive engineers, chemists, a psychologist, and an aerospace engineer, so therefore, each of us had different aims and objectives going into the test week, looking at everything from driver behaviour to the performance of engine lubricants. As we were all new to dyno testing developing a test plan was a fascinating and challenging task!
Initially, we decided to run the Prius through two "drive cycles", which are prescribed acceleration traces that are designed to show a vehicle's performance across a variety of situations - such as urban stop-start driving and motorway driving. We chose to use the WLTC (a standard test cycle) and the RTS-95 (an aggressive cycle) to test the car in different operating conditions. However, choosing the cycles proved to be the easy part as we then had to decide how to configure the driving modes, cell temperature, engine start temperature, battery state of charge, and even cabin temperature on a test-by-test basis to meet 9 people's research objectives. As you can imagine, this was quite a challenge!
In the end, we decided to run tests with the cell temperature between 23 degrees and 0 degrees with no cabin heat (wearing coats!) and focus on monitoring performance in 'EV', hybrid, and 'B' (enhanced regenerative braking) modes. Between us we've managed to gather data looking at the battery management system, the impact of driving style on energy recovery, catalyst performance, battery performance, battery thermal efficiency, and the (very complex planetary) gearbox, amongst other things!
We are now in the throws of data analysis and rapidly preparing a questionnaire and customer engagement day to get as many people in the university community as possible involved in this project to really understand how people see hybrid vehicles and what they want from the propulsion systems of the future.
You'll be able to find us and the Prius in arrivals square on the 8th of January so drop by to say hi and find out more about our Prius testing and share your views on hybrids... and have some coffee and cake!