In order to optimize the performance of an advanced hybrid system, significant changes were required in the production engine control strategies. Because the underlying controller strategy on the production Bosch engine ECU is ‘closed’ and source code strategy is never released by the OEM to a third party, an alternate solution was required.
The combination of Dana’s OpenECU engine controller, Gasoline Engine Control Strategies, and Pi’s systems and controls engineering teams provided the solution.
The initial step in implementing the OpenECU system was to characterize the base engine, necessitating removal of the engine and complete production vehicle wiring loom and engine management system from the donor vehicle and mounting on an engine dynamometer. This enabled base engine mapping for the application to be carried out, as well as characterization of sensors and actuators.
The next phase was to replace the production Bosch engine management system with the OpenECU G800. running Dana’s Gasoline Engine Control Strategies. With OpenECU on-board came the final phase where strategy specific to the hybrid vehicle application was developed.
Using Dana’s rapid controls prototyping OpenECU tool chain, the strategies were written in the MATLAB®/ Simulink® graphical methodology and then translated into auto-generated code using Real Time Workshop (RTW). The C code is compiled down to an executable that will run on the OpenECU G800. Because the hardware used for developing the controls is validated for an under hood environment, the same production ready hardware could be used if the concept evolved to fleet trials or low volume production.
The Hybrid Four-Wheel Drive Vehicle (H4V) developed by MIRA was part of a project that was equally funded by the Energy Saving Trust and MIRA. H4V is a series/parallel petrol-electric hybrid with the front axle driven by the engine and the rear axle driven by two electric motors. The hybrid powertrain is controlled by a vehicle level control unit (VCU) communicating via CAN bus to the OpenECU engine controller.
Results and Impact
The OpenECU hardware and controller development tool chain successfully enabled the H4V hybrid vehicle performance targets to be met. A CO2 rating of 104g/km was achieved and the 64mpg equivalent fuel economy was a 30% improvement over the donor vehicle. MIRA continues to use the OpenECU tool chain and acquired expertise on various research projects.