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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.

A bridged valve train configuration exhibits complex dynamic behavior due to the uniqueness of the special elephant foot/bridge/valve structure. Consequently, this system arrangement presents significant design challenges in system stability at high speed, high load, wear, no-follow and valve seating velocity, etc. An efficient way to gain a thorough understanding of the behavior of this type of valve train system and to drive the valve train design improvement is through the use of an effective dynamic simulation tool. In this paper, an advanced CAE tool developed by Ford Motor Company for the bridged type valve train simulations has been described. This automated CAE tool provides a complete virtual ADAMS-based simulation environment for the pushrod bridged valve train system analysis. This paper also presents the correlation and validation between the simulations and the measurements. The design analysis for the bridged valve train has been discussed briefly in this paper.

With more stringent emissions regulations (e.g., US EPA 2010), heat rejection control in cooling system design becomes increasingly important and a necessary part of the emissions control recipe in modern diesel engine design. Energy balance of the gas-side performance data (flow rate and temperature) with thermodynamic first law is an effective approach to analyze coolant heat rejection. In order to determine a critical engine design characteristic, base engine heat rejection percentage, an accurate assessment on various miscellaneous heat losses is required. Once the miscellaneous heat losses are known, it is convenient to use the gas-side energy balance to compute base engine coolant heat rejection. In this paper, a theoretical analysis was conducted to derive the parametric dependency of the miscellaneous losses to the ambient through the surfaces of exhaust manifold, turbocharger and engine block via convection and radiation heat transfer.

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.