Anyone who has ever forgotten to tighten the gas cap on a family car will be familiar with emission-related onboard diagnostic (OBD) systems. They emerge in various forms, including a cryptic malfunction indicator light (MIL) on the dashboard, a pesky “Check Engine” warning and the detailed troubleshooting codes that are recorded for technicians in the service bay.
The world of heavy-duty trucking is about to become very familiar with these lights and all of their related sensors.
As of the 2010 model year, selected engines from each manufacturer will need to be equipped with a system that watches over emission-controlling components – from the exhaust gas recirculation (EGR) systems that reduce NOx, to the diesel particulate filters (DPF) that capture particulate matter before it escapes through a truck’s exhaust stacks.
Whenever a problem occurs, the related fault codes will need to be recorded by the engine’s electronic control module (ECM), and a new MIL will begin to glow on the dashboard. The new monitoring systems will even need to ensure that the sensors are working as they should.
It is the first step of a rollout that will emerge over several years.
At first, the new diagnostic systems will only be required on each manufacturer’s most popular engine families for on-highway vehicles with gross vehicle weight ratings above 14,000 lbs. (Navistar, for example, will need to include the new sensors and lights on its 11- and 13-liter MaxxForce engines. Cummins will add the equipment to its ISX Family 1 models, while Volvo will add it to the 13-liter D13). But by 2013, all on-highway engines will be affected.
“This phase-in is designed to spread over a number of years the development effort required by industry and to provide industry with a learning period prior to implementing the OBD requirements on 100 percent of their highway product line,” the Environmental Protection Agency (EPA) says in its regulatory announcement, noting how the changes should add little more than $60 to the cost of an engine.
California’s OBD regulations were approved by the EPA in September, and the new federal rules that were approved in December are largely identical to those that were unveiled by the California Air Resources Board (CARB). While the requirement is new, manufacturers will be able to use some existing sensors for the work.
“Many EGR systems have had these in place,” observed Greg Gillham, Detroit Diesel’s manager of onboard diagnostics, during a 2008 Technology & Maintenance Council seminar on the topic.
For example, look at a 2009 engine and you will find sensors that monitor whether EGR rates are too low or too high. But Detroit Diesel has added a sensor in the crankcase ventilation system specifically to meet the 2010 requirements.
“Cummins will continue to utilize existing sensors that are on both the engine and the Cummins Particulate Filter, as they are today,” Cummins on-highway market spokesperson Christy Nycz added in a recent interview, noting how affected equipment will simply include new temperature sensors on the selective catalytic reduction catalyst, and a new NOx-related sensor.
For Navistar, the new requirements will see the introduction of a new mass air flow (MAF) sensor to detect fuel quantities. “All other monitors will use existing sensors for detection of emission-related failures,” says service program manager Douglas McGill.
“OBD-like diagnostics have been in place ever since the introduction of electronic engines, so the concept of performing diagnostics is nothing new,” notes Steve Berry, director of government relations for Volvo Powertrain, the supplier of engines and transmissions to Volvo Trucks North America.
“These systems, however, will have to perform according to regulated standards, and report information according to specific protocol. The most challenging aspect is calibrating the diagnostic to illuminate the MIL (in the event of a component failure) before the emissions exceed a certain threshold, as established by regulation.”
MORE TO COME
But manufacturers will not need to include some of the refined sensors that were originally proposed
