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This paper describes the verification and comparison of position control algorithms for a continuously-variable cam phaser. Robust Engineering techniques are used. Two non-linear PID control algorithms are designed to control cam phaser position. The first algorithm is a more complex control strategy while the second is a thrifted approach that seeks to reduce throughput requirements. An L18 orthogonal array is established with noise factors that affect the quality of cam phaser control. Using the orthogonal array, the number of experiment test points required to characterize the control algorithm response is reduced from 8,748 to thirty-six. The test points of the orthogonal array are investigated experimentally on a motored engine outfitted with cam phaser hardware. The desired and actual cam position data are compared and analyzed for all points in the orthogonal array.

This paper describes the development of a vacuum-decay based evaporative leak detection sub-system that meets the model year 2000 California Air Resources Board (CARB) requirements.1 The diagnostic algorithm was developed and tested to create a production intent calibration. In addition, the calibration was validated during a four month test period of diagnostic and driveability performance, which included hot ambient, high volatility fuels, and altitude. It was found to detect 0.020 inch leaks reliably in-use, while being robust to misdiagnosis of smaller leaks.