This paper presents a comprehensive state-ofthe-art review of the modeling and analysis methods for the multidisciplinary design of electric motors for various applications including vehicular power and propulsion systems and electrified powertrains. It covers the important aspects of different engineering domains such as dynamic modeling, loss calculations, demagnetization analysis, thermal modeling, acoustic noise and vibration analysis, and mechanical stress modeling. The paper intends to guide the electric motor designers through examples and results on how to apply different analysis techniques on electric motors.
Ash accumulation in diesel particulate filters, mostly from essential lubricant additives, decreases the filter's soot storage capacity, adversely affects fuel economy, and negatively impacts the filter's service life. While the adverse effects of ash accumulation on DPF performance are well known, the underlying mechanisms controlling these effects are not. To address these issues, results of detailed measurements with specially formulated lubricants, correlating ash properties to individual lubricant additives and their effects on DPF pressure drop, are presented.Investigations using the specially-formulated lubricants showed ash consisting primarily of calcium sulfates to exhibit significantly increased flow resistance as opposed to ash primarily composed of zinc phosphates. Furthermore, ash accumulated along the filer walls was found to be packed approximately 25% denser than ash accumulated in the channel end-plugs. Both lubricant chemistry and the filter's thermal history were correlated to ash packing density and distribution following DPF post-mortem analysis.In this study, a heavy-duty diesel engine was utilized in conjunction with a rapid lubricant degradation and aftertreatment ash loading system, which has been validated in detail previously against engine-out exhaust and ash accumulated in the field. Results with specially-formulated lubricants containing only calcium-based detergents, only ZDDP additives, and conventional CJ-4 oils were compared utilizing an aging cycle simulating 180,000 miles of on-road use. On-engine DPF performance evaluation, coupled with subsequent filter post-mortem analysis, clearly indicate the manner in which lubricant chemistry and exhaust conditions influence ash properties and DPF performance.The results of this work demonstrate the effects of individual lubricant additives on the resulting ash properties controlling DPF pressure drop, including ash packing density and permeability. Results will be useful in optimizing the design of the combined engine-aftertreatment-lubricant system for future diesel engines, balancing the requirements of additives for adequate engine protection with the requirements for robust aftertreatment systems.
Semiconductor power modules are core components of power electronics in electrified vehicles. Packaging technology often has a critical impact on module performance and reliability. This paper presents a comprehensive review of the automotive power module packaging technologies. The first part of this paper discusses the driving factors of packaging technology development. In the second section, the design considerations and a primary design process of module packaging are summarized. Besides, major packaging components, such as semiconductor dies, substrates, and die bonding, are introduced based on the conventional packaging structure. Next, technical details and innovative features of state-of-the-art automotive power modules from major suppliers and original equipment manufacturers are reviewed. Most of these modules have been applied in commercial vehicles. In the fourth part, the system integration concept, printed circuit board embedded packaging, three-dimensional packaging, press pack packaging, and advanced materials are categorized as promising trends for automotive applications. The advantages and drawbacks of these trends are discussed, and it is concluded that a preferable overall performance could be achieved by combining multiple technologies. INDEX TERMS Electric vehicles, power electronics, semiconductor device packaging TABLE I PRIMARY DESIGN CONSIDERATIONS OF MODULE PACKAGING Design considerations Details Size Volume, weight, power density, energy density. Electrical performance Current rating, voltage rating, switching frequency range, power loss, electrical insulation, electromagnetic interference (EMI). Thermal management Temperature distribution, thermal resistance (Rth), heat capacity, coefficient of thermal expansion (CTE). Mechanical strength Thermal stress distribution, material properties (Tensile strength, flexural strength, peel strength, etc.), external shock and vibration. Reliability and fatigue Joints failure, crack propagation, delamination, lifetime under temperature and power cycling. Manufacturability and assembly Manufacture procedure, process temperature and pressure, external connections.
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