汽車(che)(che)要(yao)跑(pao)得(de)快(kuai)，就(jiu)必(bi)須要(yao)有(you)(you)強勁的(de)動(dong)力。目前(qian)汽車(che)(che)的(de)動(dong)力系(xi)(xi)(xi)統(tong)可粗(cu)分為自然(ran)(ran)進(jin)(jin)氣(qi)(qi)系(xi)(xi)(xi)統(tong)及增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)進(jin)(jin)氣(qi)(qi)系(xi)(xi)(xi)統(tong)兩(liang)大類(lei)。在歐洲跑(pao)車(che)(che)中，除了(le)(le)寶馬汽車(che)(che)公(gong)司依(yi)然(ran)(ran)堅持使用自然(ran)(ran)進(jin)(jin)氣(qi)(qi)發動(dong)機(ji)(ji)外，其他各汽車(che)(che)公(gong)司為了(le)(le)提(ti)(ti)升(sheng)車(che)(che)輛的(de)動(dong)力性能，紛紛采(cai)用增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)系(xi)(xi)(xi)統(tong)，例(li)如：奔馳(chi)跑(pao)車(che)(che)使用機(ji)(ji)械(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)系(xi)(xi)(xi)統(tong)，紳(shen)寶汽車(che)(che)則為渦(wo)輪(lun)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)的(de)開山鼻祖(zu)。近年日系(xi)(xi)(xi)汽車(che)(che)也開始大量采(cai)用渦(wo)輪(lun)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)技術。自然(ran)(ran)進(jin)(jin)氣(qi)(qi)系(xi)(xi)(xi)統(tong)沒有(you)(you)安(an)裝任何形(xing)式的(de)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)器，只(zhi)是利(li)用活塞(sai)下行所產生的(de)負壓(ya)(ya)來吸進(jin)(jin)混(hun)合氣(qi)(qi)。雖然(ran)(ran)自然(ran)(ran)進(jin)(jin)氣(qi)(qi)系(xi)(xi)(xi)統(tong)通過可變氣(qi)(qi)門(men)正時系(xi)(xi)(xi)統(tong)能夠(gou)得(de)到較大的(de)馬力輸出，但動(dong)力的(de)提(ti)(ti)升(sheng)很(hen)有(you)(you)限(xian)。為了(le)(le)有(you)(you)效增(zeng)(zeng)(zeng)(zeng)(zeng)加(jia)發動(dong)機(ji)(ji)的(de)輸出功(gong)率，采(cai)用增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)系(xi)(xi)(xi)統(tong)可說是最有(you)(you)效的(de)方式。

最常見(jian)的發動機(ji)增壓系統有機(ji)械增壓與廢氣渦輪增壓兩種。

機械增壓

發(fa)(fa)(fa)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)以機(ji)(ji)(ji)(ji)械方式(shi)驅動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)械增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)器(qi)進(jin)行(xing)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)，稱為機(ji)(ji)(ji)(ji)械增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)。當發(fa)(fa)(fa)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)采(cai)用(yong)(yong)(yong)機(ji)(ji)(ji)(ji)械增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)時，通(tong)常由發(fa)(fa)(fa)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)曲(qu)軸(zhou)通(tong)過(guo)齒(chi)輪驅動(dong)(dong)(dong)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)器(qi)。增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)器(qi)一般采(cai)用(yong)(yong)(yong)離心式(shi)或羅茨壓(ya)(ya)(ya)氣(qi)(qi)機(ji)(ji)(ji)(ji)，個別的(de)采(cai)用(yong)(yong)(yong)螺桿(gan)式(shi)壓(ya)(ya)(ya)氣(qi)(qi)機(ji)(ji)(ji)(ji)。近年來，在國外也(ye)開始采(cai)用(yong)(yong)(yong)新型的(de)機(ji)(ji)(ji)(ji)械渦(wo)(wo)旋式(shi)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)器(qi)。因(yin)(yin)為驅動(dong)(dong)(dong)壓(ya)(ya)(ya)氣(qi)(qi)機(ji)(ji)(ji)(ji)消(xiao)(xiao)耗(hao)(hao)(hao)了(le)發(fa)(fa)(fa)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)一定的(de)輸出(chu)(chu)功率(lv)，所以機(ji)(ji)(ji)(ji)械增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)發(fa)(fa)(fa)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)的(de)熱效(xiao)率(lv)不(bu)一定得到改善，有(you)時反而比(bi)非增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)內燃(ran)(ran)機(ji)(ji)(ji)(ji)還低些。選(xuan)擇增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)壓(ya)(ya)(ya)力(li)時，首先(xian)要保證能達(da)到所要求(qiu)的(de)平均(jun)有(you)效(xiao)壓(ya)(ya)(ya)力(li)，其次要獲得盡可(ke)能低的(de)燃(ran)(ran)油(you)消(xiao)(xiao)耗(hao)(hao)(hao)率(lv)。擔這(zhe)兩個要求(qiu)對(dui)于(yu)機(ji)(ji)(ji)(ji)械增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)來說(shuo)常常是相互矛(mao)盾的(de)。如果追(zhui)求(qiu)平均(jun)有(you)效(xiao)壓(ya)(ya)(ya)力(li)，則必然導致機(ji)(ji)(ji)(ji)械效(xiao)率(lv)降(jiang)低，燃(ran)(ran)油(you)消(xiao)(xiao)耗(hao)(hao)(hao)率(lv)升(sheng)高。因(yin)(yin)此，增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)壓(ya)(ya)(ya)力(li)值的(de)選(xuan)取應在功率(lv)和燃(ran)(ran)油(you)消(xiao)(xiao)耗(hao)(hao)(hao)率(lv)兩者之間尋求(qiu)最(zui)佳的(de)妥協方案。機(ji)(ji)(ji)(ji)械增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)系統目(mu)前在歐洲車上用(yong)(yong)(yong)得較(jiao)普遍。由于(yu)機(ji)(ji)(ji)(ji)械增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)的(de)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)機(ji)(ji)(ji)(ji)是在曲(qu)軸(zhou)的(de)帶動(dong)(dong)(dong)下持續(xu)地運(yun)轉(zhuan)，因(yin)(yin)此不(bu)動(dong)(dong)(dong)產生像(xiang)渦(wo)(wo)輪增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)的(de)渦(wo)(wo)輪遲滯現象。機(ji)(ji)(ji)(ji)械增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)雖然只能提升(sheng)約10%20%的(de)動(dong)(dong)(dong)力(li)輸出(chu)(chu)，但(dan)平順連(lian)續(xu)性是渦(wo)(wo)輪增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)發(fa)(fa)(fa)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)所不(bu)及的(de)。

廢氣渦輪增壓

利用發(fa)(fa)動(dong)機(ji)(ji)(ji)廢(fei)(fei)氣(qi)(qi)(qi)(qi)能量(liang)驅動(dong)渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)器(qi)，稱為廢(fei)(fei)氣(qi)(qi)(qi)(qi)渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)（簡稱渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)），如圖所示(shi)是廢(fei)(fei)氣(qi)(qi)(qi)(qi)渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)系統(tong)。廢(fei)(fei)氣(qi)(qi)(qi)(qi)渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)的(de)(de)(de)特點(dian)是在渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)器(qi)和發(fa)(fa)動(dong)機(ji)(ji)(ji)之(zhi)間沒有(you)機(ji)(ji)(ji)械(xie)連接。它(ta)們之(zhi)間靠氣(qi)(qi)(qi)(qi)路相(xiang)通(tong)。因為壓(ya)(ya)氣(qi)(qi)(qi)(qi)機(ji)(ji)(ji)消(xiao)(xiao)耗的(de)(de)(de)功(gong)(gong)(gong)是渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)從廢(fei)(fei)氣(qi)(qi)(qi)(qi)中回收的(de)(de)(de)一(yi)部(bu)分(fen)能量(liang)，所以(yi)渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)發(fa)(fa)動(dong)機(ji)(ji)(ji)不(bu)僅可(ke)以(yi)增(zeng)(zeng)(zeng)加(jia)發(fa)(fa)動(dong)機(ji)(ji)(ji)的(de)(de)(de)功(gong)(gong)(gong)率，而且可(ke)以(yi)提(ti)(ti)高其(qi)熱效率，降低(di)燃(ran)油(you)消(xiao)(xiao)耗率。如果在轎車(che)尾部(bu)看到Turbo或者T的(de)(de)(de)標(biao)識，即表明(ming)該(gai)車(che)采用的(de)(de)(de)發(fa)(fa)動(dong)機(ji)(ji)(ji)是渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)的(de)(de)(de)。渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)器(qi)實際上是臺(tai)空(kong)氣(qi)(qi)(qi)(qi)壓(ya)(ya)縮機(ji)(ji)(ji)，它(ta)是利用發(fa)(fa)動(dong)機(ji)(ji)(ji)排出(chu)(chu)的(de)(de)(de)廢(fei)(fei)氣(qi)(qi)(qi)(qi)慣性推動(dong)渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)，渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)又帶動(dong)同軸的(de)(de)(de)葉(xie)輪(lun)(lun)(lun)壓(ya)(ya)縮由空(kong)氣(qi)(qi)(qi)(qi)濾清(qing)器(qi)管道送來(lai)的(de)(de)(de)空(kong)氣(qi)(qi)(qi)(qi)，使空(kong)氣(qi)(qi)(qi)(qi)增(zeng)(zeng)(zeng)壓(ya)(ya)后進入氣(qi)(qi)(qi)(qi)缸。當發(fa)(fa)動(dong)機(ji)(ji)(ji)轉(zhuan)速(su)提(ti)(ti)高，廢(fei)(fei)氣(qi)(qi)(qi)(qi)排出(chu)(chu)速(su)度(du)與渦(wo)(wo)(wo)(wo)輪(lun)(lun)(lun)轉(zhuan)速(su)也同步提(ti)(ti)高，葉(xie)輪(lun)(lun)(lun)就壓(ya)(ya)縮更(geng)多(duo)的(de)(de)(de)空(kong)氣(qi)(qi)(qi)(qi)進入氣(qi)(qi)(qi)(qi)缸，空(kong)氣(qi)(qi)(qi)(qi)的(de)(de)(de)壓(ya)(ya)力(li)和密度(du)增(zeng)(zeng)(zeng)大可(ke)以(yi)燃(ran)燒更(geng)多(duo)的(de)(de)(de)燃(ran)油(you)，相(xiang)應增(zeng)(zeng)(zeng)加(jia)油(you)量(liang)和調整一(yi)下發(fa)(fa)動(dong)機(ji)(ji)(ji)的(de)(de)(de)轉(zhuan)速(su)，就可(ke)以(yi)增(zeng)(zeng)(zeng)加(jia)發(fa)(fa)動(dong)機(ji)(ji)(ji)的(de)(de)(de)輸出(chu)(chu)功(gong)(gong)(gong)率。