Real-time execution models for co-simulation

In order to reduce development cycle, powertrain control and optimization is increasingly based on system modeling and several steps of simulation are needed. As an intermediate step, real-time simulation aim to prepare further test bed validations embedding the actual engine. This article discusses the challenge to find a real-time execution model offering the determinism needed to maintain the numerical results observed in offline simulation and still managing to meet real-time constraints. We first propose a conservative real-time execution model, totally deterministic but pessimistic in term of computational resources management. Then, since we need better use of these resources in order to achieve real-time simulation of representative complex models, we present different alternatives and discuss the advantages and drawbacks of each of them.