Energy optimisation using a whole vehicle simulation model

Approach

The benchmark vehicle was put through a series of test cycles at HORIBA MIRA’s facility in China to establish its baseline AER. Additionally, climatic wind tunnel testing was used to investigate its thermal performance, while characterising components such as the battery, e-motor and inverter.

Comprehensive digital analysis was carried out using a whole vehicle model to understand the system’s total energy usage. The same model was then employed to optimise the powertrain, looking at factors such as thermal management, lift-off regeneration and the implementation of a brake-by-wire system.

Meanwhile, HORIBA MIRA’s Advanced Battery Development Suite (ABDS) was used to understand cell and pack-level behaviour, enabling the engineers to replace the battery pack and optimise the usable energy.

Once optimised, the powertrain was re-evaluated in simulation and a physical prototype was built to validate the results.

Successes and benefits

The energy optimisation work carried out by HORIBA MIRA resulted in significant improvements to the vehicle’s range and efficiency. These included:

• Simulated gains of +36.8% AER and -19.5% in energy consumption for a fully-optimised solution.
• Budget and time constraints limited the physical prototype to a real-world increase of 21.3% AER.
• The above gains are entirely achieved in the powertrain (not including the battery pack change). No physical changes were required to the underlying vehicle, aside from the brake-by-wire system.
• Donor vehicle sourced. Powertrain reverse engineered and removed. Prototype vehicles developed, built and verified with revised powertrain.

HORIBA MIRA has the resources and the experience to carry out projects like this entirely in-house. We were able to provide all the services required to integrate a new e-axle and optimise its functionality.
Ben Gale, Solution Leader for Automotive Energy Efficiency, HORIBA MIRA