Development of HIL test systems for system optimization

For a customer in the automotive industry, Infotiv Test & Development was commissioned to work with the customer to develop a system for testing and optimizing a complete system with engine, exhaust gas aftertreatment and control units. The assignment was an important part of the customer's goal to move 20 percent of testing done in physical test cells to virtual testing in HIL (Hardware-In-the-Loop) test systems. Infotiv delivered a total of 4 test systems to the customer.

The system consists of engine and exhaust aftertreatment simulation models that are linked to a physical engine controller and a HIL test system. The simulation models calculate a wide range of system parameters, including temperatures, pressures, fuel consumption and emissions. Simulation models of several types are integrated into Simulink and then connected to a real-time system that simulates the sensors (analog voltages and pulse trains) and data buses (CAN) needed to test the complete system. This makes it possible to run test cycles and perform optimizations of the control system based on the simulated system.

Infotiv chose to base the real-time system on the National Instruments PXI platform. Modules for analog inputs and outputs and CAN are used. Veristand software from National Instruments is used to control and configure the system.

When Infotiv's first concept system proved successful, Infotiv was also commissioned to design and deliver several test rigs to cover the customer's increased test needs. The concept was adapted to the customer's needs and focused on implementing only the test functionalities that were most value-creating. Among other things, existing hardware was used for the components that did not need to be simulated. This allowed the customer to start using the system more quickly, but also to avoid unnecessary costs and complexity. The delivery could quickly generate value in the form of, for example, calibration of new diagnostic functions for the product development projects that were supported.

An important part of the design was to use the same software and tools that already existed in physical engine test cells. The system could therefore be effectively used to train new engineers in the teams as the knowledge of tools and procedures was transferable to physical engine testing.