Applying TRIZ Theory to Improve M998 Hummer Protective Control Box

• Main Authors: Hong-Wei PAN, 潘竑幃
• Other Authors: Chen-Feng Wu
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/92ze73

碩士 === 育達科技大學 === 資訊管理所 === 107 === Over the past 20years, the Republic of China’s Armed Forces has procured various types of High Mobility Multipurpose Wheeled Vehicles(HMMWVs) from the United States on a yearly basis in order to construct a modern national defense force that meets the needs of troops. However, the environmental and climatic conditions in Taiwan have resulted in maintenance bottlenecks for such vehicles. Their high failure rate is mostly attributed to failures in the protective control box(PCB), which leads to engine preheating failure, difficulty in starting the engine, and short battery life. Among them, electrical system failures that directly impede mission accomplishment occur the most frequently. This study thus investigated the failures in the PCB and the peripheral electrical system in the HMMWV M998 by applying Teoriya Resheniya Izobretatelskikh Zadatch(TRIZ in Russian, or in English, The Theory of Inventive Problem Solving)Theory to analyze reasons for such failures. A point of fault was identified: the failure of electromagnetic relay in the PCB was causing abnormal battery power consumption. To prevent power loss caused by failure, Armed Forces personnel disconnected the battery power cord when it was not use; however, frequently connecting and disconnecting the battery power cord wears the plug of power cord, leading to a risk of power conduction failure. Another common point of fault is the engine preheating module in the PCB. The module’s over-automated design means that the system turns on the preheating function even when unnecessary. This problem not only causes unnecessary power consumption but also induces wear to parts including glow plugs. After the aforementioned shortcomings were analyzed, this study proposed three invention principles, namely field system replacement, segmentation, and prevention. A main power switch should be installed next to the battery chamber so that the user is not required to use any tool. Furthermore, this avoids inducing wear to the plug of power cord. On the signal cable that activates automated preheating, a snap switch should be installed to enable the driver to determine the correct time to use this function in order to avoid power loss and wear to engine preheating components. Finally, the electromagnetic relay in the PCB should be replaced with a solid-state relay to prevent failure, thereby resolving the problem of abnormal battery power consumption. The repair manual of HMMWV M998 does not provide a circuit diagram of a PCB. This study therefore produced a PCB circuit diagram with each element connection marked to provide a reference for relevant maintenance personnel to perform maintenance tasks and teach others to do so. Keywords: High Mobility Multipurpose Wheeled Vehicle(HMMWV)M998, Protective Control Box, Teoriya Resheniya Izobretatelskikh Zadatch(TRIZ), Engine Preheating, Relay