汽車(che)要(yao)跑(pao)得快(kuai)，就(jiu)必(bi)須要(yao)有強勁的動力(li)(li)。目前(qian)汽車(che)的動力(li)(li)系(xi)統(tong)(tong)可(ke)粗(cu)分為自然(ran)進(jin)氣系(xi)統(tong)(tong)及增(zeng)壓(ya)(ya)(ya)進(jin)氣系(xi)統(tong)(tong)兩大(da)類。在歐洲跑(pao)車(che)中，除了寶馬汽車(che)公(gong)(gong)司依然(ran)堅持使用自然(ran)進(jin)氣發(fa)動機外，其(qi)他各汽車(che)公(gong)(gong)司為了提升車(che)輛的動力(li)(li)性能，紛紛采(cai)用增(zeng)壓(ya)(ya)(ya)系(xi)統(tong)(tong)，例如：奔(ben)馳(chi)跑(pao)車(che)使用機械增(zeng)壓(ya)(ya)(ya)系(xi)統(tong)(tong)，紳寶汽車(che)則為渦輪增(zeng)壓(ya)(ya)(ya)的開(kai)山鼻祖。近年(nian)日系(xi)汽車(che)也開(kai)始大(da)量采(cai)用渦輪增(zeng)壓(ya)(ya)(ya)技術。自然(ran)進(jin)氣系(xi)統(tong)(tong)沒(mei)有安裝任何(he)形式的增(zeng)壓(ya)(ya)(ya)器，只是利用活塞下行(xing)所產生的負壓(ya)(ya)(ya)來吸進(jin)混合氣。雖然(ran)自然(ran)進(jin)氣系(xi)統(tong)(tong)通過可(ke)變氣門正時系(xi)統(tong)(tong)能夠得到較大(da)的馬力(li)(li)輸(shu)出(chu)，但(dan)動力(li)(li)的提升很(hen)有限(xian)。為了有效(xiao)增(zeng)加發(fa)動機的輸(shu)出(chu)功(gong)率，采(cai)用增(zeng)壓(ya)(ya)(ya)系(xi)統(tong)(tong)可(ke)說是最(zui)有效(xiao)的方式。

最常見的發(fa)動機增壓(ya)系統有機械增壓(ya)與廢氣渦(wo)輪增壓(ya)兩種。

機械增壓

發(fa)(fa)動機(ji)(ji)以機(ji)(ji)械(xie)(xie)(xie)方式(shi)驅(qu)動機(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)器(qi)進行增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)，稱為機(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)。當發(fa)(fa)動機(ji)(ji)采(cai)(cai)用機(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)時，通(tong)常由發(fa)(fa)動機(ji)(ji)曲軸(zhou)(zhou)通(tong)過齒(chi)輪(lun)驅(qu)動增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)器(qi)。增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)器(qi)一般采(cai)(cai)用離心式(shi)或羅茨壓(ya)(ya)(ya)(ya)氣機(ji)(ji)，個別(bie)的(de)(de)(de)(de)采(cai)(cai)用螺桿式(shi)壓(ya)(ya)(ya)(ya)氣機(ji)(ji)。近年來，在(zai)國(guo)外也開始采(cai)(cai)用新型的(de)(de)(de)(de)機(ji)(ji)械(xie)(xie)(xie)渦旋式(shi)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)器(qi)。因為驅(qu)動壓(ya)(ya)(ya)(ya)氣機(ji)(ji)消耗(hao)了發(fa)(fa)動機(ji)(ji)一定的(de)(de)(de)(de)輸出功率(lv)，所以機(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)發(fa)(fa)動機(ji)(ji)的(de)(de)(de)(de)熱效(xiao)率(lv)不(bu)(bu)一定得到改善，有(you)(you)時反(fan)而(er)比非增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)內燃機(ji)(ji)還低(di)些。選擇(ze)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)壓(ya)(ya)(ya)(ya)力(li)(li)時，首先要保證能達到所要求(qiu)的(de)(de)(de)(de)平(ping)(ping)均有(you)(you)效(xiao)壓(ya)(ya)(ya)(ya)力(li)(li)，其次要獲(huo)得盡(jin)可(ke)能低(di)的(de)(de)(de)(de)燃油(you)(you)消耗(hao)率(lv)。擔這兩個要求(qiu)對于機(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)來說常常是相互(hu)矛盾的(de)(de)(de)(de)。如果追求(qiu)平(ping)(ping)均有(you)(you)效(xiao)壓(ya)(ya)(ya)(ya)力(li)(li)，則必然導致機(ji)(ji)械(xie)(xie)(xie)效(xiao)率(lv)降低(di)，燃油(you)(you)消耗(hao)率(lv)升高。因此，增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)壓(ya)(ya)(ya)(ya)力(li)(li)值的(de)(de)(de)(de)選取應在(zai)功率(lv)和(he)燃油(you)(you)消耗(hao)率(lv)兩者(zhe)之間尋求(qiu)最佳(jia)的(de)(de)(de)(de)妥協方案。機(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)系統目(mu)前(qian)在(zai)歐洲車上用得較普遍。由于機(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)的(de)(de)(de)(de)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)機(ji)(ji)是在(zai)曲軸(zhou)(zhou)的(de)(de)(de)(de)帶動下持續(xu)地運轉(zhuan)，因此不(bu)(bu)動產生像(xiang)渦輪(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)的(de)(de)(de)(de)渦輪(lun)遲(chi)滯現象。機(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)雖然只能提升約10%20%的(de)(de)(de)(de)動力(li)(li)輸出，但平(ping)(ping)順連續(xu)性(xing)是渦輪(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)發(fa)(fa)動機(ji)(ji)所不(bu)(bu)及的(de)(de)(de)(de)。

廢氣渦輪增壓(ya)

利用發(fa)動(dong)(dong)(dong)(dong)機(ji)廢(fei)氣(qi)(qi)(qi)(qi)能(neng)量驅動(dong)(dong)(dong)(dong)渦(wo)(wo)(wo)(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)器(qi)，稱為廢(fei)氣(qi)(qi)(qi)(qi)渦(wo)(wo)(wo)(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)（簡稱渦(wo)(wo)(wo)(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)），如(ru)圖所示是(shi)(shi)(shi)廢(fei)氣(qi)(qi)(qi)(qi)渦(wo)(wo)(wo)(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)系統。廢(fei)氣(qi)(qi)(qi)(qi)渦(wo)(wo)(wo)(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)的(de)(de)特點(dian)是(shi)(shi)(shi)在渦(wo)(wo)(wo)(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)器(qi)和發(fa)動(dong)(dong)(dong)(dong)機(ji)之間沒有機(ji)械連接。它(ta)(ta)們(men)之間靠氣(qi)(qi)(qi)(qi)路相通(tong)。因為壓(ya)(ya)(ya)(ya)氣(qi)(qi)(qi)(qi)機(ji)消(xiao)耗的(de)(de)功(gong)是(shi)(shi)(shi)渦(wo)(wo)(wo)(wo)輪(lun)(lun)從廢(fei)氣(qi)(qi)(qi)(qi)中(zhong)回收的(de)(de)一(yi)部(bu)分能(neng)量，所以(yi)渦(wo)(wo)(wo)(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)發(fa)動(dong)(dong)(dong)(dong)機(ji)不僅(jin)可(ke)以(yi)增(zeng)(zeng)(zeng)加發(fa)動(dong)(dong)(dong)(dong)機(ji)的(de)(de)功(gong)率(lv)(lv)，而且可(ke)以(yi)提高(gao)其熱效(xiao)率(lv)(lv)，降低燃(ran)油(you)(you)消(xiao)耗率(lv)(lv)。如(ru)果(guo)在轎車(che)尾部(bu)看到Turbo或者T的(de)(de)標(biao)識(shi)，即表明該車(che)采用的(de)(de)發(fa)動(dong)(dong)(dong)(dong)機(ji)是(shi)(shi)(shi)渦(wo)(wo)(wo)(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)的(de)(de)。渦(wo)(wo)(wo)(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)器(qi)實際上是(shi)(shi)(shi)臺空(kong)(kong)氣(qi)(qi)(qi)(qi)壓(ya)(ya)(ya)(ya)縮機(ji)，它(ta)(ta)是(shi)(shi)(shi)利用發(fa)動(dong)(dong)(dong)(dong)機(ji)排出(chu)(chu)的(de)(de)廢(fei)氣(qi)(qi)(qi)(qi)慣(guan)性推動(dong)(dong)(dong)(dong)渦(wo)(wo)(wo)(wo)輪(lun)(lun)，渦(wo)(wo)(wo)(wo)輪(lun)(lun)又帶動(dong)(dong)(dong)(dong)同(tong)軸的(de)(de)葉輪(lun)(lun)壓(ya)(ya)(ya)(ya)縮由空(kong)(kong)氣(qi)(qi)(qi)(qi)濾(lv)清器(qi)管道送來的(de)(de)空(kong)(kong)氣(qi)(qi)(qi)(qi)，使空(kong)(kong)氣(qi)(qi)(qi)(qi)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)后進入氣(qi)(qi)(qi)(qi)缸(gang)。當發(fa)動(dong)(dong)(dong)(dong)機(ji)轉速(su)(su)提高(gao)，廢(fei)氣(qi)(qi)(qi)(qi)排出(chu)(chu)速(su)(su)度與渦(wo)(wo)(wo)(wo)輪(lun)(lun)轉速(su)(su)也(ye)同(tong)步提高(gao)，葉輪(lun)(lun)就(jiu)壓(ya)(ya)(ya)(ya)縮更多的(de)(de)空(kong)(kong)氣(qi)(qi)(qi)(qi)進入氣(qi)(qi)(qi)(qi)缸(gang)，空(kong)(kong)氣(qi)(qi)(qi)(qi)的(de)(de)壓(ya)(ya)(ya)(ya)力(li)和密度增(zeng)(zeng)(zeng)大可(ke)以(yi)燃(ran)燒(shao)更多的(de)(de)燃(ran)油(you)(you)，相應增(zeng)(zeng)(zeng)加油(you)(you)量和調整一(yi)下發(fa)動(dong)(dong)(dong)(dong)機(ji)的(de)(de)轉速(su)(su)，就(jiu)可(ke)以(yi)增(zeng)(zeng)(zeng)加發(fa)動(dong)(dong)(dong)(dong)機(ji)的(de)(de)輸出(chu)(chu)功(gong)率(lv)(lv)。