Innovative device and process for the oil leakage measure

The paper deals with an innovative device and a process to measure the oil leakage or the leak rate through the seals, specially regarding the valve steam seals (VSS). Valve stem seals, in automotive applications, must assure a correct valve stem lubrication. It is the " controlled leakage" concept. Inadequate flow causes increased valve-train wear-rate, premature failure, noise and higher temperatures; excessive flow causes oil consumption, lower efficiency (engine and catalyst) and environment concerns. It is extremely important to develop a leak-rate measurement system in order to meet emission requirements and durability performance of this type of industrial product. The problem is solved by the measurement of very small leakage, of around 0.01 cm³ by the device and the process presented in this paper. The paper presents the device, actually patent pending, the procedure and the experimental results obtained.