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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.

The development of commercial vehicles demand a rigorous and relatively expedient integration and validation to be performed in order to have the vehicle delivered to a satisfied customer. In today's market, the end customer often request for vehicles with various customizations and requirements for vocational performance, such as load and fuel economy. These requirements often run into conflict with vehicle dynamics fundamentals such as ride and handling. Examples of such concern are vocation bodies that do not have weight distributed unevenly or even ones that bias the static load distribution of the vehicle such that ride and handling are affected because of change in bounce, roll and pitch natural frequencies. One tool that can be used to develop and evaluate vehicle response to provide guidance for production vehicles is multibody dynamics. Unlike the passenger car industry, no two trucks rolling down the assembly line are necessarily the same.

Selective Catalytic Reduction (SCR) systems provide excellent NOX control for diesel engines provided the exhaust aftertreatment inlet temperature remains at 200° C or higher. Since diesel engines run lean, extended light load operation typically causes exhaust temperatures to fall below 200° C and SCR conversion efficiency diminishes. Heated urea dosing systems are being developed to allow dosing below 190° C. However, catalyst face plugging remains a concern. Close coupled SCR systems and lower temperature formulation of SCR systems are also being developed, which add additional expense. Current strategies of post fuel injection and retarded injection timing increases fuel consumption. One viable keep-warm strategy examined in this paper is cylinder deactivation (CDA) which can increase exhaust temperature and reduce fuel consumption.

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.