圖8-1 一種減壓活門式滑油系統
Fig. 8-1 A pressure relief valve type oil system.

全流量系統
 
7．雖然對于具有低軸承腔壓力的發動機來說，軸承腔壓力不會隨發動機轉速的增加而過量增加，減壓活門系統可以滿意地工作。但是，對于具有高軸承腔壓力的發動機來說，它就成了不符合要求的系統。例如，假如軸承腔的最大壓力為90磅／平方英寸，為了在滑油供油噴嘴處產生40磅／平方英寸的壓力降，就要求減壓活門設定壓力為l30磅／平方英寸。這時就要使油泵很大，并且在較低的轉速下難以與要求的滑油流量相匹配。
system. Scavenge pumps return the oil to the tank via the oil cooler. On entering the tank, the oil is de-aerated ready for recirculation.
Full flow system
7. Although the pressure relief valve system operates satisfactorily for engines which have a low bearing chamber pressure, which does not unduly increase with engine speed, it becomes an undesirable system for engines which have high chamber pressures. For example, if a bearing chamber has a maximum pressure of 90 lb. per sq. in. It would require a pressure relief valve setting of 130 lb. per sq. in. to produce a pressure drop of 40 lb. per sq. in. at the oil feed jet. This results in the
Lubrication
need for large pumps and difficulty in matching the required oil flow at slower speeds.
8. The full flow system achieves the desired oil flow rates throughout the complete engine speed range by dispensing with the pressure relief valve and allowing the pressure pump delivery pressure to supply directly the oil feed jets. Fig. 8-2 shows an example of this system which may be found on a turbo-fan engine. The pressure pump size is determined by the flow required at maximum engine speed. The use of this system allows smaller pressure and scavenge pumps to be used since the large volume of oil which is spilled by the pressure relief valve system at maximum engine speed is obviated.

圖8-2 一種全流量式滑油系統
8.全流量系統可以在整個發動機轉速范圍內達到要求的滑油流量，它不用減壓活門，而允許增壓泵直接向滑油供油噴嘴供壓。圖8-2示出了這種系統的一個例子，它可以在渦輪風扇發動機上找到。增壓油泵的尺寸由發動機最大轉速下要求的滑油流量決定。由于不像減壓活門系統那樣在最大發動機轉速下溢出大量的滑油，所以使用本系統允許使用較小的壓力和較小的回油泵。
Fig. 8-2 A full flow type oil system.
來自滑油箱
滑油壓差開關
減壓活門
高壓油濾
滑油泵組件
供油
回油
通風空氣
離心式通風機
節流后溢油
流回滑油箱
油氣分離器盤
滑油壓力傳感器和低壓警告開關
燃油冷卻滑油散熱器        空氣冷卻滑油散熱器
9．為了防止高的滑油壓力損壞油濾或滑油散熱器，安裝了限壓活門，使滑油繞過這些裝置而經旁路回油。一般情況下，這些活門只有在冷起動條件下或當發生堵塞時才工作。通過壓差開關可以在駕駛艙中提前給出油濾堵塞的警告指示，該開關感受油濾進口和出口的壓力差。
9. To prevent high oil pressures from damaging filters or coolers, pressure limiting valves are fitted to by-pass these units. These valves normally only operate under cold starting conditions or in the event of a blockage. Advance warning of a blocked filter may be indicated in the cockpit by a differential pressure switch which senses an increase in the pressure difference between the inlet and outlet of the filter.
Total loss (expendable) system
10. For engines which run for periods of short duration, such as booster and vertical lift engines,
Lubrication

the total loss oil system is generally used. The system is simple and incurs low weight penalties because it requires no oil cooler, scavenge pump or filters. On some engines oil is delivered in a continuous flow to the bearings by a plunger-type pump, indirectly driven from the compressor shaft; on others it is delivered by a piston-type pump operated by fuel pressure (fig. 8-3). In the latter, the oil supply is automatically selected by the high pressure fuel shut-off valve (cock) during engine starting and is delivered as a single shot to the front and rear bearings. On some engines provision is made for a
滑油／空氣霧引射噴口
油箱壓力
供滑油
滑油／空氣霧
高壓燃油
低壓燃油
總損耗（可消耗的）系統

10．對于短時間運轉的發動機，如助推發動機和垂直升力發動機，通常使用總損耗滑油系統。這種系統簡單而且重量方而的負擔較小，因為它不需要滑油散熱器，回油泵或油濾。在某些發動機上，滑油由一個柱塞式泵連續地向軸承供油。該泵由上壓氣機軸間接驅動。在其它發動機上，滑油由燃油壓力(圖8-3)驅動的活塞式泵供應。對于后者，供油是由高
壓燃油停車開關在發動機起動時自動選擇的，向？后軸承只射油一次。在某些發動機上，還備有某種措施按預定的時間間隔第二次射油，但是只向后軸承射油。
后軸承
空心出口導向葉片
壓氣機空氣
一次注油滑油泵
油門裝置
燃油槽

圖8-3 一種總損耗(消耗性)滑油系統
Fig. 8-3 A total loss (expendable) oil system.

11．滑油在潤滑了燃油裝置和前軸承之后，由前軸承排入集油槽，然后通過一個引射噴口噴入主燃氣流。流過后軸承的滑油排入軸承后面的收油池，滑油在離心力作用下留在那里直至發動機停車。然后該滑油由位于排氣裝置內錐中的中心管排出機外。
　
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