Search Results

Recently, composite materials/structures are getting increasingly used in the automotive and aerospace industry. Defects issue is commonly associated with the use of composite materials/structures. Reliable Non-Destructive Evaluation (NDE) of composite structures is still challenging due to the existence of small size defects. In this research, a hybrid approach is used to accurately determine small size internal defects. In this hybrid approach, X-Ray Computed Tomography is used as a reference to accurately determine all defect locations, then a digital shearography method is used to conduct fast NDE for in-line testing. The critical shearographic NDE parameters such as shearing angle, shearing distance and loading amount are determined and optimized based on the X-ray CT scan result. From the comparison of X-ray CT scan results and digital shearography NDE results, the detection rate of digital shearography for defects with a size of larger than 1mm is from 91.91% to 97.30%.

Cylinder deactivation (CDA) is an effective method to adjust the engine displacement for maximum output and improve fuel economy by adjusting the number of active cylinders in combustion engines. A Switching Roller Finger Follower (SRFF) is an economic solution for CDA that minimizes changes and preserves the overall width, height, or length of Dual Overhead Cam (DOHC) engines. The CDA SRFF provides the flexibility of either transferring or suppressing the camshaft movement to the valves influencing the engine performance and fuel economy by reducing the pumping losses. This paper addresses the performance and durability of the CDA SRFF system to meet the reliability for gasoline passenger car engines. Extensive tests were conducted to demonstrate the dynamic stability at high engine speeds and the system capacity of switching between high and low engine displacement within one camshaft revolution.