Engine-in-the-Loop Drive Cycle Simulation
At a glance
Millbrook has developed world-class engine drive cycle simulation capabilities to speed up prototype engine development and emissions calibrations. Its approach minimises downtime and cuts down on the number of chassis dyno tests required.
Millbrook runs engine drive cycle simulations to include the characteristics of a vehicle’s driveline and driver attributes, within a full CVS emissions suite environment. It allows the engine drive cycle simulation test data to be compared directly with legislative vehicle drive cycle tests and enables the customer to make changes to hardware, calibrations and driver attributes without leaving the simulated environment.
Validating the Driver and Driveline Model
When a customer tasked Millbrook to help find the ideal driveline configurations to optimise the emissions results across their vehicle platform, the first exercise was to correlate Millbrook’s test facility against the customer’s own facilities. Initially, the customer provided a ‘black box’ model for Millbrook to use; protecting their sensitive vehicle data and intellectual property. After successful completion of these tests, Millbrook then parameterised its own models, producing equivalent emissions results to that of the customer’s model, but more importantly to that of historical emissions data from a ‘golden’ verification vehicle in the customer’s test fleet.
Once Millbrook’s open model had been validated, the actual test programme could then begin. Numerous driveline configurations were created through parameter changes within the models, and a number of legislative and bespoke emissions drive cycles were performed, ultimately providing the customer with the information to determine preferred driveline configurations across their vehicle platform.
Full CVS Emissions Suite
Using its full CVS emissions suite, Millbrook was able to include a large number of emissions parameters in the programme, including:
- Engine (pre-cat) emissions
- Tailpipe (post-cat) emissions
- Modal dilute emissions
- Bag emissions
- Particulate filter weights
- Particulate number counter
- Particulate mass
Correlating the Engine Test Bed and a Chassis Dynamometer
The correlation exercise and test programme used a number of recognised global emission drive cycles, including FTP75, WLTC, NEDC and custom drive cycles.
With both the customer’s and Millbrook’s models, the correlation exercise was successful, proving that an engine on a testbed could match the emissions results of a vehicle on a chassis dyno.
With its own, fully accessible model, Millbrook made changes to the simulated hardware and driver behaviours very quickly. This significantly reduced the downtime compared to making real world changes to the vehicle.
In addition to this, Millbrook carried out engine calibration changes, analysing the resultant impact on engine-out emissions. These changes could be implemented, tested and analysed far quicker than the equivalent vehicle test on a chassis dynamometer, maximising the benefit to the customer.