Adam J. Kotrba

Design of a High-Efficiency Minimum-Torque-Ripple 12-V/1-kW Three-Phase BLDC Motor Drive System for Diesel Engine Emission Reductions

A 12-V motor drive system using an onboard battery is promising in vehicle applications, e.g., to rotate an air pump to adjust its air delivery to the burner, thereby providing autonomous exhaust temperature control for the conventional diesel engine vehicle. The 12-V/1-kW motor drive system proposed in this paper consists of a series-resonant LLC MOSFET full-bridge converter, which provides high-efficiency power transfer by implementing zero voltage switching and boosts the dc bus to ~300 V, and an insulated-gate bipolar transistor inverter, which provides the high-side phase currents to a 1-kW/6000-r/min brushless dc motor (BLDC). This design secures the high efficiency, low cost, and low volume. Meanwhile, with the variable output voltage of this dc/dc converter, this paper realizes a commutation torque-ripple reduction method, which will minimize the mechanical vibration. Experimental results on this prototype system demonstrate that: 1) the LLC dc/dc part efficiency is 97.6% with 92% of the inverter efficiency; and 2) the motor commutation torque ripple is reduced close to zero.

Development of a light vehicle diesel aftertreatment system with DOC DPF and urea SCR

Meeting stringent emission regulations is a challenge to light vehicle diesel engines because of complexities of aftertreatment system, packaging constraints, and emission regulations. This article intends to introduce development philosophy from developing a light vehicle aftertreatment system that includes diesel oxidisation catalyst (DOC), catalytic diesel particulate filter (CDPF), urea injector and urea selective catalytic reduction (SCR). The development focus was on overall component planning to meet system emission targets at the early stage, system geometrical optimisations to meet pressure target at the intermediate stage, and design improvements of urea SCR module at the final stage. Both tests and modelling were employed seamlessly to reach decisions on major design directions. Significant efforts were spent on SCR mixing optimisation. Multiple mixer concepts were explored; the final developed SCR system was tested and able to meet all performance objectives. The roles of computational fluid d...

Design of a high-efficiency 12V/1kW 3-phase BLDC motor drive system for diesel engine emissions reductions

For the conventional vehicle, an efficient and effective heat source that provides autonomous exhaust temperature control is of interest, and one solution is a diesel burner which needs to adjust its air delivery based on transient operating conditions through a three-phase motor drive system powered by a 12V lead-acid battery. The system proposed in this paper consists of a series-resonant LLC MOSFET full-bridge converter, which provides high-efficiency energy transfer through implementing Zero Voltage Switching, and an IGBT inverter which provides the high-side phase currents to a 1kW brushless DC motor. Experimental results on this prototype system demonstrate the LLC DC/DC part efficiency is 97.6% and the inverter efficiency is 92%.

Failure mechanisms and modes analysis of vehicle exhaust components and systems

Abstract The basic functions of vehicle exhaust components and systems are to control emissions, noise, and manage thermal energy. Increasingly stringent government regulations on emissions and fuel economy challenge the exhaust designers and manufacturers to a degree that they have not yet experienced. In order to meet the regulations and customer requirements, vehicle exhaust systems are becoming more complex with increased service life. Failure mechanisms and modes and related durability and reliability performance assessment of vehicle exhausts become a more important concern to product design and validation engineers. In this chapter, the trend of emission control products and the challenges related to materials failure mechanisms and modes, such as fatigue, creep, oxidation, corrosion, erosion or their interactions, are reviewed in detail. Probabilistic failure data analysis, failure cause determination, effective failure prevention strategies, materials screening, and material ranking are also provided and discussed.

Combustion Model for a Homogeneous Turbocharged Gasoline Direct-Injection Engine

Homogeneous charge is a preferred operation mode of gasoline direct-injection (GDI) engines. However, a limited amount of work exists in the literature for combustion models of this mode of engine operation. Current work describes a model developed to study combustion in a homogeneous charge GDI engine. The model was validated using experimental data from a 1.6 L Ford EcoBoost R engine, tested at the U.S. EPA. The combustion heat release was approximated using a double-Wiebe function, to account for the rapid initial premixed combustion followed by a gradual diffusion-like state of combustion, as observed in this GDI engine. Variables of Wiebe correlations were adjusted into a semipredictive combustion model. The effectiveness of semipredictive combustion model was tested in prediction of in-cylinder pressures. The root-mean-square (RMS) errors between experiments and numerical results were within 2.5% of in-cylinder peak pressures during combustion. The semipredictive combustion model was further studied to develop a predictive combustion model. The performance of predictive combustion model was examined by regenerating the experimental cumulative heat release. The heat release analysis developed for the GDI engine was further applied to a dual mode, turbulent jet ignition (DM-TJI) engine. DM-TJI is a distributed combustion technology with the potential to provide diesel-like efficiencies and minimal engine-out emissions for spark-ignition engines. The DM-TJI engine was observed to offer a faster burn rate and lower in-cylinder heat transfer compared to the GDI engine. [DOI: 10.1115/1.4039813]