Search Results

Heavy-duty diesel on-board diagnostics (OBD) regulations are being phased in around the world with varying degrees of similarity. This is occurring at a time when heavy-duty diesel emission regulations are driving complex and elaborate emission control strategies. Unique circumstances led the European heavy-duty diesel market to adopt selective catalytic reduction (SCR) as the primary solution for meeting strict Euro 4 emission levels. This paper is a review of the challenges of diagnosing an SCR system based on the Euro 4 OBD regulation and considers the future challenges of SCR diagnostics that lie ahead in the North American market.

The development and release process for Cummins first US HD OBD certified product encountered numerous hurdles. Beyond the purely "technical" difficulties, there were also challenges related to our product development processes. This presentation provides recommendations for HD OBD product development processes & improvements. Topics will include: Training needs for program management, Performance tuning strategies vs. OBD needs, Planning for post-certification product changes, etc. Presenter Greg Moore, Cummins Inc.

The presenter will discuss challenges introduced by OBD in developing a product for worldwide markets and the impact of varying worldwide requirements for OBD performance and certification. Presenter Benjamin Zwissler, Cummins Inc.

The interest for NOx estimators (also known as virtual sensors or inferential sensors) has increased over the recent years due to benefits attributed to cost and performance. NOx estimators are typically installed to improve On-Board Diagnostics (OBD) monitors or to lower bill of material costs by replacing physical NOx sensors. This paper presents initial development results of a virtual engine-out NOx estimator planned for the implementation on an ECM. The presented estimator consists of an airpath observer and a NOx combustion model. The role of the airpath observer is to provide input values for the NOx combustion model such as the states of the gas at the intake and exhaust manifolds. It contains a nonlinear mean-value model of the airpath suitably transformed for an efficient and robust implementation on an ECM. The airpath model uses available sensory information in the vehicle to correct predictions of the gas states.

Production PM sensors are now available and are likely to be key components of PM aftertreatment systems designed to meet 2013 OBD requirements. In this paper a highly simplified analysis is used to give insight into the sensor response of resistive-based devices, and to motivate possible diagnostic strategies. The method has been applied to successive sets of FTP data recorded with DPF's of different failure levels, and despite the very approximate nature of the underlying model, the method appears to discriminate reliably between them.