The continual tightening of vehicle emission standards has led to decreases in pollution associated with vehicles but not to the levels that the standards target. Research into why has highlighted a disconnect between the emissions emitted by vehicles during real-world driving versus under laboratory conditions. This disconnect is mostly caused by the fact that laboratory drive cycles don’t properly represent the range and variety of conditions that occur in real driving scenarios (ex. cold ambient temperatures, driver behavior, road grade).
As a result, many regulatory bodies around the world have started to adopt regulations that attempt to establish vehicle emission standards that apply to real-world driving. Such standards, commonly referred to as Real Driving Emissions (RDE), usually mean that the vehicle is driven on public roads while recording emissions rather than doing so in a controlled laboratory setting. This is also occasionally called off-cycle driving, as the vehicles are not being driven using standard regulatory cycles such as the WLTC, FTP-75 or JC08.
This presents a large challenge to the automotive industry which needs to ensure that vehicles are compliant with emission regulations under real driving conditions that vary greatly and are only defined as a set of boundary conditions. Testing can be conducted to try and ensure compliance, but it is both costly and can only be carried out once a prototype vehicle is built. Relying on testing alone is a huge risk. If a vehicle is discovered to be non-compliant late in the development process, it will likely result in delays and it will be extremely costly to re-design the powertrain and aftertreatment system.
To help engineers mitigate the risk that a vehicle won’t meet the applicable real driving emission standards, we developed simulation solutions such as vRDE. The latest development is GT-RealDrive, a route generation tool that helps engineers study how vehicle and system models perform under real-driving scenarios.
GT-RealDrive models real-world driving by creating off-cycles routes based on user defined start and end addresses. The cycles take into account traffic conditions, elevation, and traffic signals, effectively generating a cycle representative of real-world driving. Since GT-RealDrive is self-contained within GT-SUITE, the drive cycles created can be directly used in any GT-SUITE vehicle model to simulate off-cycle driving in the same manner as the standard regulatory cycles.