Emissions enforcement is having a moment. A big one.
And while one automaker is reeling from the aftermath of using a ‘defeat device’ (software that recognizes when the car is undergoing emissions testing), would you be surprised to know that this isn’t the first time that’s happened?
Per an article in Automotive Engineering International entitled “VW emissions scandal will impact future engine controls, testing” (October 5, 2015): “In 1998 EPA levied a $1.1 billion fine on seven heavy-duty diesel engine makers—the largest civil penalty ever imposed for violations of an environmental law—for using “defeat devices” in the engines’ controllers. This software altered injection timing and boosted fuel efficiency while illegally bypassing the emission control equipment on 1.3 million trucks.”
But—at least with the heavy duty, on-road vehicle community—a lot has changed since 1998.
So much so, that SAE International has published an updated version of Recommended Practice J1939/84, a document designed to verify that heavy duty, on-road vehicles are capable of communicating a required set of information related to emissions.
The Recommended Practice, “OBD Communications Compliance Test Cases for Heavy Duty Components and Vehicles,” sets guidelines for communicating in accordance with the diagnostic messages specified in SAE J1939/73, with the use of an off-board diagnostic tool interface.
Mark Zachos, chair of SAE International’s J1939/84 Task Force under the Truck Bus Control and Communications Network Committee, said the Recommended Practice was created to assure that heavy duty engine manufacturers are complying with standardized emission testing regulations. Zachos said the Recommended Practice assures that all engines, regardless of the manufacturer, can be tested under the same set of tests to determine if they meet governmental emission regulations.
“Engines designs differ from manufacturer to manufacturer, so we needed to create a Recommended Practice that could apply to all engines,” Zachos said. “This is what SAE International does best. We were able to create a Recommended Practice that works on all fronts.”
SAE J1939/84 describes the tests, methods and results for verifying diagnostic communications from an off-board diagnostic tool, such as a scanner, to a vehicle or component. The Recommended Practice serves as a guide for testing vehicles for compliance with California Air Resources Board and other requirements for emissions-related, on-board diagnostic functions for heavy duty engines used in medium and heavy duty vehicles.
The development of heavy duty, on-board diagnostic regulations by the U.S. EPA and the California Air Resources Board require that diagnostic message services are exercised to evaluate diagnostic communication standardization requirements on production vehicles.
“This updated version of SAE J1939/84 revises the testing procedures in section six of the older version of the document in order to implement a two-operating cycle failure detection process for production vehicle evaluation,” said Zachos. “The tests also exercise diagnostic executive features, such as three-drive cycle accounting, freeze frame management and the general demeanor in addition to the demonstration of interface functions. Detailed criteria for some tests are described in a normative appendix, Appendix A, which was inserted before the output report examples that are now in Appendix B. The revisions were extensive enough to warrant publication as a complete revision.”