| 摘要 |
A method for sensing when the quantity of oil in the crankcase of a reciprocating piston engine is inadequate for proper lubrication while the engine is operating. During engine operation, the crankcase gas pressure cycles between positive and negative values as the piston reciprocates. Positive crankcase gas pressures are vented through a check valve. The resulting cyclic vacuum in the crankcase has a peak and average magnitude which is a function of the quantity of oil in the crankcase. For a constant speed and substantially constant load engine, the crankcase vacuum can be used to indicate the approximate quantity of oil in the crankcase. For constant or variable speed and load engines, a drop in the crankcase vacuum below a predetermined level can be used to automatically stop the engine prior to damage by inadequate lubrication. |
