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Browsing by Author "Lohse-Busch, Henning"

Now showing 1 - 3 of 3
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    Development and Applications of the Modular Automotive Technology Testbed (MATT) to Evaluate Hybrid Electric Powertrain Components and Energy Management Strategies
    Lohse-Busch, Henning (Virginia Tech, 2009-05-11)
    This work describes the design, development and research applications of a Modular Automotive Technology Testbed (MATT). MATT is built to evaluate technology components in a hybrid vehicle system environment. MATT can also be utilized to evaluate energy management and torque split control strategies and to produce physical measured component losses and emissions to monitor emissions behavior. In the automotive world, new technology components are first developed on a test bench and then they are integrated into a prototype vehicle for transient evaluation from the vehicle system perspective. This process is expensive and the prototype vehicles are typically inflexible in hardware and software configuration. MATT provides flexibility in component testing through its component module approach. The flexible combination of modules provides a vehicle environment to test and evaluate new technology components. MATT also has an open control system where any energy management and torque split strategy can be implemented. Therefore, the control's impact on energy consumption and emissions can be measured. MATT can also emulate different types and sizes of vehicles. MATT is a novel, unique, flexible and powerful automotive research tool that provides hardware-based data for specific research topics. Currently, several powertrain modules are available for use on MATT: a gasoline engine module, a hydrogen engine module, a virtual scalable energy storage and virtual scalable motor module, a manual transmission module and an automatic transmission module. The virtual battery and motor module uses some component Hardware-In-the-Loop (HIL) principles by utilizing a physical motor powered from the electric grid in conjunction with a real time simulation of a battery and a motor model. This module enables MATT to emulate a wide variety of vehicles, ranging from a conventional vehicle to a full performance electric vehicle with a battery pack that has virtually unlimited capacity. A select set of PHEV research studies are described in this dissertation. One of these studies had an outcome that influenced the PHEV standard test protocol development by SAE. Another study investigated the impact of the control strategy on emissions of PHEVs. Emissions mitigation routines were integrated in the control strategies, reducing the measured emissions to SULEV limits on a full charge test. A special component evaluation study featured in this dissertation is the transient performance characterization of a supercharged hydrogen internal combustion engine on MATT. Four constant air-fuel ratio combustions are evaluated in a conventional vehicle operation on standard drive cycles. Then, a variable air fuel ratio combustion strategy is developed and the test results show a significant fuel economy gain compared to other combustion strategies, while NOx emissions levels are kept low.
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    Thermal Overload Capabilities of an Electric Motor and Inverter Unit Through Modeling Validated by Testing
    Lohse-Busch, Henning (Virginia Tech, 2004-05-28)
    VPT, Inc and the U.S. Dept. of Energy have sponsored the development of a high-speed 12 kW AC induction motor to drive automotive fuel cell air compressors. As one part of the development, thermal considerations and the cooling system are detailed in this paper. The motor and inverter are packaged in one unit with the heat sink in the middle. The heat sink is a cold chamber designed to absorb the maximum heat losses from the unit. Empirical data was used to validate the model of the cold chamber and finalize the design. A lumped capacitance finite-difference model was developed to simulate the entire motor inverter assembly. The individual components of the thermal model were tested and the data was used to calibrate and validate the thermal model. Using the model, the thermal overload conditions were investigated. The limiting factors are the stator copper winding temperatures, which can damage the plastic slot liners. The double current test was simulated and operating temperatures of the system remained within thermal limits for 4 minutes. As a conclusion from the model, the thermal resistances from the stator to the case or the heat sink need to be reduced. Integrating the motor casing and end plate to the heat sink, rather than building it in sections, would reduce the thermal contact resistances. Also the copper winding ends in the stator could be coated in material that would bond to the case, thus increasing heat transfer from the windings to the case.
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    Understanding the challenges in HEV 5-cycle fuel economy calculations based on dynamometer test data
    Meyer, Mark J. (Virginia Tech, 2011-11-16)
    EPA testing methods for calculation of fuel economy label ratings, which were revised beginning in 2008, use equations that weight the contributions of fuel consumption results from multiple dynamometer tests to synthesize city and highway estimates that reflect average U.S. driving patterns. The equations incorporate effects with varying weightings into the final fuel consumption, which are explained in this thesis paper, including illustrations from testing. Some of the test results used in the computation come from individual phases within the certification driving cycles. This methodology causes additional complexities for hybrid electric vehicles, because although they are required to have charge-balanced batteries over the course of a full drive cycle, they may have net charge or discharge within the individual phases. The fundamentals of studying battery charge-balance are discussed in this paper, followed by a detailed investigation of the implications of per-phase charge correction that was undertaken through testing of a 2010 Toyota Prius at Argonne National Laboratory's vehicle dynamometer test facility. Using the charge-correction curves obtained through testing shows that phase fuel economy can be significantly skewed by natural charge imbalance, although the end effect on the fuel economy label is not as large. Finally, the characteristics of the current 5-cycle fuel economy testing method are compared to previous methods through a vehicle simulation study which shows that the magnitude of impact from mass and aerodynamic parameters vary between labeling methods and vehicle types.