Sharpening the design

摘要

For US supplier Novo Products, satisfying these requirements went beyond learning new kinds of vacuum/flow test techniques. When customers began requesting prototype flow-test data presented in graphical form, Novo had to find test capabilities that no known instrument could provide. They ultimately met that challenge - and cut design testing time significantly - with a customised combination of mass-flow leak-tester and PC-based test-networking software. According to Novo manufacturing engineer Brent Veeneman, each engine design presents a different relationship between the amount of vacuum and the amount of crankcase pressure allowed to vent. Buyers define flow values desired at three vacuum levels for production QC testing, but they want design prototypes verified by curves plotting flows at up to 20 levels. These vacuum levels, termed Delta Points, typically range between 1 and 20 InHg (inches of mercury), while flow values might be anywhere between 0.2 and 8 cfm (cubic feet per minute).