汽(qi)車(che)(che)要(yao)(yao)跑(pao)得(de)(de)快，就必須要(yao)(yao)有(you)強勁的(de)(de)(de)動(dong)力。目前汽(qi)車(che)(che)的(de)(de)(de)動(dong)力系(xi)(xi)統(tong)(tong)(tong)可(ke)(ke)粗分為(wei)自(zi)然(ran)進(jin)氣(qi)(qi)系(xi)(xi)統(tong)(tong)(tong)及增壓(ya)(ya)進(jin)氣(qi)(qi)系(xi)(xi)統(tong)(tong)(tong)兩大類(lei)。在歐(ou)洲跑(pao)車(che)(che)中，除了(le)寶(bao)馬(ma)汽(qi)車(che)(che)公司依(yi)然(ran)堅持使用(yong)自(zi)然(ran)進(jin)氣(qi)(qi)發動(dong)機(ji)外，其他各(ge)汽(qi)車(che)(che)公司為(wei)了(le)提升車(che)(che)輛的(de)(de)(de)動(dong)力性能，紛紛采(cai)用(yong)增壓(ya)(ya)系(xi)(xi)統(tong)(tong)(tong)，例如：奔馳跑(pao)車(che)(che)使用(yong)機(ji)械增壓(ya)(ya)系(xi)(xi)統(tong)(tong)(tong)，紳寶(bao)汽(qi)車(che)(che)則(ze)為(wei)渦輪(lun)增壓(ya)(ya)的(de)(de)(de)開(kai)山鼻祖。近年日系(xi)(xi)汽(qi)車(che)(che)也開(kai)始(shi)大量采(cai)用(yong)渦輪(lun)增壓(ya)(ya)技術。自(zi)然(ran)進(jin)氣(qi)(qi)系(xi)(xi)統(tong)(tong)(tong)沒有(you)安裝任何形(xing)式的(de)(de)(de)增壓(ya)(ya)器，只是(shi)利用(yong)活塞下行所產生的(de)(de)(de)負(fu)壓(ya)(ya)來吸進(jin)混合氣(qi)(qi)。雖然(ran)自(zi)然(ran)進(jin)氣(qi)(qi)系(xi)(xi)統(tong)(tong)(tong)通過可(ke)(ke)變氣(qi)(qi)門正(zheng)時系(xi)(xi)統(tong)(tong)(tong)能夠得(de)(de)到較大的(de)(de)(de)馬(ma)力輸出，但動(dong)力的(de)(de)(de)提升很(hen)有(you)限。為(wei)了(le)有(you)效增加發動(dong)機(ji)的(de)(de)(de)輸出功(gong)率，采(cai)用(yong)增壓(ya)(ya)系(xi)(xi)統(tong)(tong)(tong)可(ke)(ke)說是(shi)最(zui)有(you)效的(de)(de)(de)方式。

最(zui)常見的發動機(ji)增(zeng)壓(ya)(ya)系(xi)統(tong)有機(ji)械(xie)增(zeng)壓(ya)(ya)與廢(fei)氣渦輪增(zeng)壓(ya)(ya)兩種。

機械增壓

發(fa)動(dong)機(ji)(ji)(ji)以機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)方式驅動(dong)機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)器進行增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)，稱為機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)。當發(fa)動(dong)機(ji)(ji)(ji)采(cai)用機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)時(shi)，通常(chang)由發(fa)動(dong)機(ji)(ji)(ji)曲軸通過(guo)齒輪(lun)驅動(dong)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)器。增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)器一般采(cai)用離心式或羅茨壓(ya)(ya)(ya)(ya)(ya)(ya)氣機(ji)(ji)(ji)，個別的(de)(de)(de)采(cai)用螺桿(gan)式壓(ya)(ya)(ya)(ya)(ya)(ya)氣機(ji)(ji)(ji)。近年來，在國外(wai)也開(kai)始(shi)采(cai)用新型的(de)(de)(de)機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)渦(wo)旋式增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)器。因(yin)為驅動(dong)壓(ya)(ya)(ya)(ya)(ya)(ya)氣機(ji)(ji)(ji)消耗了(le)發(fa)動(dong)機(ji)(ji)(ji)一定(ding)的(de)(de)(de)輸出(chu)功率，所以機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)發(fa)動(dong)機(ji)(ji)(ji)的(de)(de)(de)熱效(xiao)率不(bu)一定(ding)得(de)到改善，有(you)(you)時(shi)反而比非增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)內燃機(ji)(ji)(ji)還低(di)些。選(xuan)擇增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)時(shi)，首先要(yao)保證能(neng)達到所要(yao)求的(de)(de)(de)平均有(you)(you)效(xiao)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)，其次要(yao)獲得(de)盡可能(neng)低(di)的(de)(de)(de)燃油消耗率。擔這兩(liang)(liang)個要(yao)求對于機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)來說常(chang)常(chang)是相互矛(mao)盾的(de)(de)(de)。如果追求平均有(you)(you)效(xiao)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)，則必然導致機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)效(xiao)率降低(di)，燃油消耗率升高。因(yin)此(ci)，增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)值的(de)(de)(de)選(xuan)取(qu)應(ying)在功率和(he)燃油消耗率兩(liang)(liang)者(zhe)之間(jian)尋求最佳的(de)(de)(de)妥協(xie)方案。機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)系統(tong)目前在歐洲車上(shang)用得(de)較普(pu)遍(bian)。由于機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)(de)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)機(ji)(ji)(ji)是在曲軸的(de)(de)(de)帶動(dong)下持續地運轉，因(yin)此(ci)不(bu)動(dong)產生像渦(wo)輪(lun)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)(de)渦(wo)輪(lun)遲滯現象。機(ji)(ji)(ji)械(xie)(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)雖然只能(neng)提升約10%20%的(de)(de)(de)動(dong)力(li)輸出(chu)，但平順(shun)連續性是渦(wo)輪(lun)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)發(fa)動(dong)機(ji)(ji)(ji)所不(bu)及的(de)(de)(de)。

廢氣渦輪增壓

利(li)用(yong)發動(dong)(dong)(dong)機(ji)(ji)廢氣(qi)(qi)(qi)(qi)能量(liang)驅動(dong)(dong)(dong)渦(wo)(wo)(wo)輪(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)器(qi)(qi)，稱為(wei)(wei)廢氣(qi)(qi)(qi)(qi)渦(wo)(wo)(wo)輪(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)（簡稱渦(wo)(wo)(wo)輪(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)），如(ru)圖所(suo)示是(shi)(shi)廢氣(qi)(qi)(qi)(qi)渦(wo)(wo)(wo)輪(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)系(xi)統。廢氣(qi)(qi)(qi)(qi)渦(wo)(wo)(wo)輪(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)的(de)(de)(de)(de)特(te)點是(shi)(shi)在渦(wo)(wo)(wo)輪(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)器(qi)(qi)和發動(dong)(dong)(dong)機(ji)(ji)之間(jian)沒有機(ji)(ji)械連(lian)接。它們之間(jian)靠氣(qi)(qi)(qi)(qi)路相(xiang)通(tong)。因為(wei)(wei)壓(ya)(ya)(ya)氣(qi)(qi)(qi)(qi)機(ji)(ji)消耗(hao)(hao)的(de)(de)(de)(de)功是(shi)(shi)渦(wo)(wo)(wo)輪(lun)從廢氣(qi)(qi)(qi)(qi)中回收的(de)(de)(de)(de)一部(bu)分能量(liang)，所(suo)以渦(wo)(wo)(wo)輪(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)發動(dong)(dong)(dong)機(ji)(ji)不僅可以增(zeng)(zeng)(zeng)加(jia)發動(dong)(dong)(dong)機(ji)(ji)的(de)(de)(de)(de)功率，而且可以提(ti)(ti)高其熱效率，降低燃(ran)(ran)油消耗(hao)(hao)率。如(ru)果在轎車尾(wei)部(bu)看到Turbo或者T的(de)(de)(de)(de)標識，即表明該車采用(yong)的(de)(de)(de)(de)發動(dong)(dong)(dong)機(ji)(ji)是(shi)(shi)渦(wo)(wo)(wo)輪(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)的(de)(de)(de)(de)。渦(wo)(wo)(wo)輪(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)器(qi)(qi)實際上是(shi)(shi)臺空氣(qi)(qi)(qi)(qi)壓(ya)(ya)(ya)縮機(ji)(ji)，它是(shi)(shi)利(li)用(yong)發動(dong)(dong)(dong)機(ji)(ji)排出的(de)(de)(de)(de)廢氣(qi)(qi)(qi)(qi)慣性推動(dong)(dong)(dong)渦(wo)(wo)(wo)輪(lun)，渦(wo)(wo)(wo)輪(lun)又帶(dai)動(dong)(dong)(dong)同軸的(de)(de)(de)(de)葉輪(lun)壓(ya)(ya)(ya)縮由空氣(qi)(qi)(qi)(qi)濾清器(qi)(qi)管道送來的(de)(de)(de)(de)空氣(qi)(qi)(qi)(qi)，使空氣(qi)(qi)(qi)(qi)增(zeng)(zeng)(zeng)壓(ya)(ya)(ya)后進入氣(qi)(qi)(qi)(qi)缸(gang)。當(dang)發動(dong)(dong)(dong)機(ji)(ji)轉速提(ti)(ti)高，廢氣(qi)(qi)(qi)(qi)排出速度與渦(wo)(wo)(wo)輪(lun)轉速也同步提(ti)(ti)高，葉輪(lun)就(jiu)壓(ya)(ya)(ya)縮更(geng)多(duo)的(de)(de)(de)(de)空氣(qi)(qi)(qi)(qi)進入氣(qi)(qi)(qi)(qi)缸(gang)，空氣(qi)(qi)(qi)(qi)的(de)(de)(de)(de)壓(ya)(ya)(ya)力和密度增(zeng)(zeng)(zeng)大可以燃(ran)(ran)燒更(geng)多(duo)的(de)(de)(de)(de)燃(ran)(ran)油，相(xiang)應增(zeng)(zeng)(zeng)加(jia)油量(liang)和調(diao)整一下發動(dong)(dong)(dong)機(ji)(ji)的(de)(de)(de)(de)轉速，就(jiu)可以增(zeng)(zeng)(zeng)加(jia)發動(dong)(dong)(dong)機(ji)(ji)的(de)(de)(de)(de)輸出功率。