R944C挖掘機檢修供油系統的工作原理是采用單泵、高壓管和噴油器組成的供油系統（簡稱PLD供油系統）。安徽挖掘機翻新需要通過經驗豐富的維修者在進行適當的程序以后來完成修復工作，通過維修人員的清洗，保障在其內部沒有污物。合肥挖掘機翻新第一臺液壓挖掘機由法國波克蘭工廠發明成功。由于液壓技術的應用，20世紀40年代有了在拖拉機上配裝液壓反鏟地懸掛式挖掘機。合肥挖掘機再制造在挖掘機(ji)的(de)(de)(de)整體(ti)(ti)(ti)構(gou)造里，齒輪扮演著重要的(de)(de)(de)劫色，一(yi)旦挖掘機(ji)的(de)(de)(de)齒輪表面出現裂(lie)痕，那么維修人員必須(xu)在第一(yi)時間修復齒輪。 柴油(you)(you)(you)(you)機(ji)凸輪軸驅(qu)動(dong)進排氣門的(de)(de)(de)運動(dong)，驅(qu)動(dong)單(dan)泵(beng)(beng)(beng)(beng)(beng)(beng)挺桿。 當(dang)(dang)(dang)凸輪旋轉時，泵(beng)(beng)(beng)(beng)(beng)(beng)的(de)(de)(de)壓(ya)(ya)(ya)頭(tou)向上移(yi)動(dong)，并且(qie)泵(beng)(beng)(beng)(beng)(beng)(beng)的(de)(de)(de)壓(ya)(ya)(ya)頭(tou)向上移(yi)動(dong)。 控(kong)(kong)(kong)制(zhi)器(ECU)根(gen)據柴油(you)(you)(you)(you)機(ji)轉速傳感器發(fa)出的(de)(de)(de)電(dian)信號，控(kong)(kong)(kong)制(zhi)單(dan)泵(beng)(beng)(beng)(beng)(beng)(beng)上部回(hui)(hui)油(you)(you)(you)(you)關閉閥(fa)的(de)(de)(de)電(dian)磁(ci)線圈(quan)通(tong)(tong)電(dian)和斷電(dian)，然后控(kong)(kong)(kong)制(zhi)回(hui)(hui)油(you)(you)(you)(you)關閉閥(fa)的(de)(de)(de)開閉。 當(dang)(dang)(dang)燃油(you)(you)(you)(you)壓(ya)(ya)(ya)力達到(dao)噴(pen)射壓(ya)(ya)(ya)力時，燃油(you)(you)(you)(you)將通(tong)(tong)過噴(pen)油(you)(you)(you)(you)器噴(pen)入燃燒(shao)室，從而實現柴油(you)(you)(you)(you)機(ji)的(de)(de)(de)運行。 圖(tu)中(zhong)(zhong)示出了這(zhe)種(zhong)類(lei)型(xing)的(de)(de)(de)挖掘機(ji)柴油(you)(you)(you)(you)發(fa)動(dong)機(ji)的(de)(de)(de)供(gong)(gong)油(you)(you)(you)(you)系統。 1. 回(hui)(hui)油(you)(you)(you)(you)關閉閥(fa)安裝在單(dan)泵(beng)(beng)(beng)(beng)(beng)(beng)的(de)(de)(de)上部，其電(dian)磁(ci)線圈(quan)的(de)(de)(de)通(tong)(tong)電(dian)持(chi)續時間決(jue)定單(dan)泵(beng)(beng)(beng)(beng)(beng)(beng)的(de)(de)(de)供(gong)(gong)油(you)(you)(you)(you)量。 當(dang)(dang)(dang)螺線管(guan)線圈(quan)斷電(dian)時，單(dan)體(ti)(ti)(ti)泵(beng)(beng)(beng)(beng)(beng)(beng)的(de)(de)(de)返回(hui)(hui)油(you)(you)(you)(you)通(tong)(tong)道打(da)開，并且(qie)即使單(dan)體(ti)(ti)(ti)泵(beng)(beng)(beng)(beng)(beng)(beng)中(zhong)(zhong)的(de)(de)(de)柱塞(sai)已經開始泵(beng)(beng)(beng)(beng)(beng)(beng)送油(you)(you)(you)(you)，也不能(neng)建立(li)高壓(ya)(ya)(ya)。 只有當(dang)(dang)(dang)電(dian)磁(ci)閥(fa)通(tong)(tong)電(dian)且(qie)回(hui)(hui)油(you)(you)(you)(you)通(tong)(tong)道關閉時，油(you)(you)(you)(you)壓(ya)(ya)(ya)才(cai)能(neng)快速上升，高壓(ya)(ya)(ya)燃料(liao)才(cai)通(tong)(tong)過高壓(ya)(ya)(ya)燃料(liao)管(guan)進入燃料(liao)噴(pen)射器噴(pen)射燃料(liao)。 當(dang)(dang)(dang)電(dian)磁(ci)線圈(quan)斷電(dian)時，回(hui)(hui)油(you)(you)(you)(you)通(tong)(tong)道打(da)開，單(dan)個泵(beng)(beng)(beng)(beng)(beng)(beng)迅(xun)速溢出并減壓(ya)(ya)(ya)，供(gong)(gong)油(you)(you)(you)(you)停止。 單(dan)泵(beng)(beng)(beng)(beng)(beng)(beng)的(de)(de)(de)工作循(xun)環如圖(tu)所(suo)示

如圖(tu)2所(suo)示，單(dan)體泵有四個工作行程(cheng)，如下所(suo)述(shu)。吸(xi)入行程(cheng): 當凸輪(lun)轉(zhuan)動(dong)(dong)時(shi)，柱(zhu)塞(sai)(sai)(sai)向下驅(qu)(qu)動(dong)(dong)，使(shi)油(you)(you)(you)(you)泵的油(you)(you)(you)(you)通過回(hui)油(you)(you)(you)(you)密封閥(fa)進入柱(zhu)塞(sai)(sai)(sai)腔(qiang)。預加載行程(cheng): 凸輪(lun)驅(qu)(qu)動(dong)(dong)柱(zhu)塞(sai)(sai)(sai)向上(shang)，加壓(ya)柱(zhu)塞(sai)(sai)(sai)腔(qiang)內(nei)的燃料。此(ci)時(shi)回(hui)油(you)(you)(you)(you)閥(fa)不關(guan)閉(bi)，柱(zhu)塞(sai)(sai)(sai)腔(qiang)內(nei)，燃油(you)(you)(you)(you)保持低壓(ya)狀態。輸(shu)出行程(cheng): 凸輪(lun)繼續驅(qu)(qu)動(dong)(dong)柱(zhu)塞(sai)(sai)(sai)向上(shang)，此(ci)時(shi)電磁線(xian)(xian)圈動(dong)(dong)力(li)大，使(shi)油(you)(you)(you)(you)回(hui)關(guan)閉(bi)閥(fa)門(men)，柱(zhu)塞(sai)(sai)(sai)腔(qiang)內(nei)燃油(you)(you)(you)(you)壓(ya)力(li)上(shang)升(sheng)。當燃料達到噴(pen)射壓(ya)力(li)時(shi)，噴(pen)射器噴(pen)射燃料。減壓(ya)沖程(cheng): 凸輪(lun)繼續旋轉(zhuan)，推動(dong)(dong)柱(zhu)塞(sai)(sai)(sai)向上(shang)，此(ci)時(shi)電磁線(xian)(xian)圈已斷電，燃油(you)(you)(you)(you)噴(pen)射完畢(bi)，回(hui)油(you)(you)(you)(you)關(guan)閉(bi)閥(fa)門(men)打開，柱(zhu)塞(sai)(sai)(sai)腔(qiang)內(nei)有油(you)(you)(you)(you)。

2.挖掘機(ji)(ji)(ji)(ji)維修故障排除。首先檢查柴油(you)(you)(you)機(ji)(ji)(ji)(ji)空(kong)氣(qi)濾清器(qi)無堵塞，增壓器(qi)運轉(zhuan)正常，中冷正常。其次，用專用的(de)SCULI軟(ruan)件檢查柴油(you)(you)(you)機(ji)(ji)(ji)(ji)的(de)供(gong)(gong)(gong)油(you)(you)(you)量(liang)，發現(xian)柴油(you)(you)(you)機(ji)(ji)(ji)(ji)在低怠(dai)速時供(gong)(gong)(gong)油(you)(you)(you)量(liang)不斷(duan)變化，確定(ding)(ding)柴油(you)(you)(you)機(ji)(ji)(ji)(ji)供(gong)(gong)(gong)油(you)(you)(you)系統有故障。之后的(de)柴油(you)(you)(you)機(ji)(ji)(ji)(ji)轉(zhuan)速傳感器(qi)、柴油(you)(you)(you)機(ji)(ji)(ji)(ji)控制(zhi)器(qi)(ECU)、柴油(you)(you)(you)濾清器(qi)、輸油(you)(you)(you)泵(beng)、噴油(you)(you)(you)器(qi)、供(gong)(gong)(gong)油(you)(you)(you)管路都沒有發現(xian)問題。但更換新的(de)單(dan)(dan)體(ti)泵(beng)后，發現(xian)柴油(you)(you)(you)機(ji)(ji)(ji)(ji)在低怠(dai)速下(xia)運行穩定(ding)(ding)，并且“嗡嗡、嗡嗡”的(de)異響消失。因(yin)此，確定(ding)(ding)故障是由(you)單(dan)(dan)體(ti)泵(beng)磨損引起(qi)的(de)。

3. 維(wei)修挖掘(jue)機(ji)(ji)主要原(yuan)因進行分析問題分析研究(jiu)認為，柴(chai)油(you)機(ji)(ji)低怠速時轉速系統不穩定(ding)出現故障(zhang)(zhang)，原(yuan)因是供(gong)油(you)量（噴(pen)油(you)量）不穩定(ding)。而供(gong)油(you)量不穩的(de) 根源是單(dan)體泵存在一些故障(zhang)(zhang)，其(qi)發(fa)生各種故障(zhang)(zhang)的(de) 部位可(ke)能有(you) 2 處(chu)：一是通過(guo)柱(zhu)塞腔(qiang)產生影響(xiang)燃油(you)信(xin)息泄漏，二是利用電磁(ci)線圈內部控制(zhi)的(de) 回(hui)油(you)封閉閥產生許(xu)多燃油(you)泄漏。單(dan)體泵安裝在柴(chai)油(you)機(ji)(ji)缸體上(shang)，其(qi)柱(zhu)塞腔(qiang)下(xia)側位于一個凸輪上(shang)方。