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A diesel engine multi-cylinder valvetrain model including a hydraulic engine braking system was developed. The model can be used for valvetrain dynamics analysis in both engine firing and braking conditions. Moreover, it can be used to investigate engine braking performance with conjugated analysis by combining the valvetrain model with an engine thermodynamic cycle simulation model. Dynamic valve lift profiles, which are important for accurate engine performance simulations, can be simulated with the model, including valve floating prediction for each cylinder during engine braking. The valvetrain model was used in the design of a diesel engine brake system and in the analysis of engine braking performance at the sea level and different high altitude and ambient temperature conditions. Valvetrain dynamics and the impact of EGR (exhaust gas recirculation) valve leakage or opening on engine braking performance were also evaluated.

Beginning in 2010, implementation of on-board diagnostics (OBD) is mandatory for all the heavy-duty engine applications in the United States. The task of developing OBD strategies and calibrating them is a challenging one. The process involves a strong interdependency on base engine emissions, controls and regulations. On top of that the strategies developed as a result of the regulatory requirements need to go through a stringent and time-intensive process of software implementation and integration. The recent increasing demands to minimize the development process have been pushing the envelope on the methodologies used in developing the strategies and the calibration for robust monitoring. The goal of this paper is to provide a concise overview of a process utilized to help the development, testing and calibration of the OBD strategies on a 2010 model year heavy-duty diesel engine.

The two most important issues for diesel engine system engineers to handle engine applications are how to coordinate technical relationships in an organization/team and how to acquire working knowledge of different applications for system integration. This paper is the first part of a series of three inter-related papers (parts) addressing diesel engine applications (i.e., Part 1 - the relationship among applications, engine system design, systems engineering, and organization structure; Part 2 - general performance characteristics of diesel engine applications; and Part 3 - specific or special emissions, operating, and design characteristics of different applications). Specialization, departmentalization, and integration are the three most critical aspects in organization design for engine product development.

Diesel engine performance and design characteristics are affected by applications. Understanding general performance characteristics and the relationship between engine system design and applications is important for diesel engine system design engineers. This paper is the Part 2 of a series of three companion papers (parts) addressing diesel engine applications (i.e., Part 1 - organization design and systems engineering; Part 2 - general performance characteristics; and Part 3 - operating and design characteristics of different applications). It illustrates important general characteristics with selected examples, and highlights key issues and commonalities of different applications that engine system design engineers need to know. Series design and multi-purpose design are summarized. Four core equations in an engine air system theory are proposed in order to reveal the parametric dependency of pumping-loss-related parameters.

This paper is the third part of a series of three papers (parts) that address diesel engine applications. It provides an overview on the differences in emissions, operation, and design characteristics between eight categories of various diesel engine applications that engine system design engineers need to know, including on-road heavy-duty, on-road light-duty, land-based mobile off-road, locomotive, marine, stationary, alternative fuels and biodiesel, and two-stroke diesel engines. The analysis technique of competitive benchmarking mapping is introduced by using a large amount of production engine application data to reveal design trends. Two empirical formulae are developed for the relationship between engine performance and design parameters. A summary table of engine system design considerations and priorities for different applications is developed as a design guideline.

With more stringent emissions regulations, effective emission modeling on NOx and soot for both on-road and off-road diesel engines becomes increasingly important for diesel engine system design and real-time engine controls. In this paper, a heuristic macro-parameter-dependent approach is proposed by combining theoretical analysis with semi-empirical method. The proposed modeling approach is different from the existing methods, such as empirical modeling, phenomenological modeling, and three-dimensional KIVA modeling. The proposed model uses the macro parameters of engine performance, both cycle-average (e.g., air-to-fuel ratio, EGR rate) and in-cylinder instantaneous data (e.g., cylinder pressure trace) as input. The model computes NOx and soot as a function of crank angle. A concept of “time-variant virtual space zones (burning, burned, and unburned)” is proposed based on the fraction of fuel burnt.