These advanced checks have resulted in development of many new diagnostic monitors, of varying types, and a whole new internal software infrastructure to handle tracking, reporting, and self-verification of OBD related items. Due to this amplified complexity and the consequences surrounding a shortfall in meeting regulatory requirements, efficient and thorough validation of the OBD system in the powertrain control software is critical. Hardware-in-the-Loop (HIL) simulation provides the environment in which the needed efficiency and thoroughness for validating the OBD system can be achieved. A HIL simulation environment consisting of engine, aftertreatment, and basic vehicle models can be employed, providing the ability for software developers, calibration engineers, OBD experts, and test engineers to examine and validate both facets of OBD software: diagnostic monitors and diagnostic infrastructure (i.e., fault memory management). HIL simulation benches with fault insertion modules are used as the first step in verifying the simplest, traditional, open-/short-circuit diagnostics on sensors and actuators, in addition to other basic functional monitors. Once the fundamentals are verified, simulation of diverse ambient and operating conditions is performed to examine proper performance of threshold monitors and rationality checks. The following presentation demonstrates how such an application of HIL simulation for OBD validation can be developed and undertaken. In addition, successes achieved by using the HIL simulation approach are highlighted, and an exploration of the challenges and limitations are discussed.
PresenterJim Priest, Daimler Trucks North America