汽(qi)(qi)(qi)車(che)要(yao)跑得快，就(jiu)必須要(yao)有(you)(you)強勁(jing)的(de)動(dong)(dong)力(li)。目前汽(qi)(qi)(qi)車(che)的(de)動(dong)(dong)力(li)系(xi)(xi)(xi)統(tong)可粗分為自然(ran)(ran)進(jin)(jin)氣系(xi)(xi)(xi)統(tong)及增(zeng)(zeng)壓(ya)進(jin)(jin)氣系(xi)(xi)(xi)統(tong)兩大類。在歐洲跑車(che)中，除了(le)(le)寶(bao)馬汽(qi)(qi)(qi)車(che)公司依然(ran)(ran)堅持使用(yong)自然(ran)(ran)進(jin)(jin)氣發動(dong)(dong)機(ji)外，其他各汽(qi)(qi)(qi)車(che)公司為了(le)(le)提升(sheng)車(che)輛的(de)動(dong)(dong)力(li)性(xing)能，紛(fen)紛(fen)采(cai)(cai)用(yong)增(zeng)(zeng)壓(ya)系(xi)(xi)(xi)統(tong)，例如：奔馳跑車(che)使用(yong)機(ji)械增(zeng)(zeng)壓(ya)系(xi)(xi)(xi)統(tong)，紳寶(bao)汽(qi)(qi)(qi)車(che)則為渦(wo)輪(lun)增(zeng)(zeng)壓(ya)的(de)開山鼻祖。近年(nian)日系(xi)(xi)(xi)汽(qi)(qi)(qi)車(che)也(ye)開始大量采(cai)(cai)用(yong)渦(wo)輪(lun)增(zeng)(zeng)壓(ya)技(ji)術。自然(ran)(ran)進(jin)(jin)氣系(xi)(xi)(xi)統(tong)沒(mei)有(you)(you)安裝(zhuang)任何形(xing)式(shi)的(de)增(zeng)(zeng)壓(ya)器，只是利用(yong)活塞下(xia)行所產生的(de)負壓(ya)來吸進(jin)(jin)混合氣。雖然(ran)(ran)自然(ran)(ran)進(jin)(jin)氣系(xi)(xi)(xi)統(tong)通(tong)過可變氣門(men)正時(shi)系(xi)(xi)(xi)統(tong)能夠得到較大的(de)馬力(li)輸(shu)出(chu)，但(dan)動(dong)(dong)力(li)的(de)提升(sheng)很(hen)有(you)(you)限。為了(le)(le)有(you)(you)效增(zeng)(zeng)加(jia)發動(dong)(dong)機(ji)的(de)輸(shu)出(chu)功(gong)率，采(cai)(cai)用(yong)增(zeng)(zeng)壓(ya)系(xi)(xi)(xi)統(tong)可說是最有(you)(you)效的(de)方式(shi)。

最常見的(de)發動機增(zeng)壓(ya)系統有(you)機械(xie)增(zeng)壓(ya)與廢氣渦輪增(zeng)壓(ya)兩(liang)種。

機(ji)械(xie)增壓

發(fa)動機(ji)(ji)(ji)(ji)(ji)以機(ji)(ji)(ji)(ji)(ji)械(xie)(xie)方(fang)式驅(qu)(qu)動機(ji)(ji)(ji)(ji)(ji)械(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)進行增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)，稱為(wei)機(ji)(ji)(ji)(ji)(ji)械(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)。當發(fa)動機(ji)(ji)(ji)(ji)(ji)采(cai)用(yong)機(ji)(ji)(ji)(ji)(ji)械(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)時(shi)，通(tong)(tong)常(chang)由(you)發(fa)動機(ji)(ji)(ji)(ji)(ji)曲軸(zhou)通(tong)(tong)過齒輪驅(qu)(qu)動增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)。增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)一般采(cai)用(yong)離心式或羅茨壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)氣(qi)機(ji)(ji)(ji)(ji)(ji)，個別的(de)(de)(de)(de)采(cai)用(yong)螺桿式壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)氣(qi)機(ji)(ji)(ji)(ji)(ji)。近(jin)年來，在國外也(ye)開(kai)始采(cai)用(yong)新型(xing)的(de)(de)(de)(de)機(ji)(ji)(ji)(ji)(ji)械(xie)(xie)渦(wo)旋式增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)。因(yin)為(wei)驅(qu)(qu)動壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)氣(qi)機(ji)(ji)(ji)(ji)(ji)消(xiao)耗(hao)了發(fa)動機(ji)(ji)(ji)(ji)(ji)一定(ding)的(de)(de)(de)(de)輸出(chu)功率(lv)(lv)(lv)(lv)，所(suo)以機(ji)(ji)(ji)(ji)(ji)械(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)發(fa)動機(ji)(ji)(ji)(ji)(ji)的(de)(de)(de)(de)熱效(xiao)率(lv)(lv)(lv)(lv)不(bu)一定(ding)得到改(gai)善，有(you)時(shi)反而比非(fei)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)內(nei)燃機(ji)(ji)(ji)(ji)(ji)還低些。選擇增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)力時(shi)，首先要保證能(neng)達到所(suo)要求的(de)(de)(de)(de)平(ping)均(jun)有(you)效(xiao)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)力，其次要獲得盡可能(neng)低的(de)(de)(de)(de)燃油(you)消(xiao)耗(hao)率(lv)(lv)(lv)(lv)。擔這(zhe)兩(liang)個要求對于(yu)機(ji)(ji)(ji)(ji)(ji)械(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)來說常(chang)常(chang)是相互矛(mao)盾的(de)(de)(de)(de)。如果追(zhui)求平(ping)均(jun)有(you)效(xiao)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)力，則(ze)必(bi)然導致機(ji)(ji)(ji)(ji)(ji)械(xie)(xie)效(xiao)率(lv)(lv)(lv)(lv)降低，燃油(you)消(xiao)耗(hao)率(lv)(lv)(lv)(lv)升高。因(yin)此，增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)力值(zhi)的(de)(de)(de)(de)選取應在功率(lv)(lv)(lv)(lv)和燃油(you)消(xiao)耗(hao)率(lv)(lv)(lv)(lv)兩(liang)者之間尋(xun)求最佳(jia)的(de)(de)(de)(de)妥協(xie)方(fang)案。機(ji)(ji)(ji)(ji)(ji)械(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)系統目前在歐(ou)洲(zhou)車上用(yong)得較(jiao)普(pu)遍(bian)。由(you)于(yu)機(ji)(ji)(ji)(ji)(ji)械(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)(de)(de)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)是在曲軸(zhou)的(de)(de)(de)(de)帶動下持續地運轉，因(yin)此不(bu)動產生像(xiang)渦(wo)輪增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)(de)(de)渦(wo)輪遲(chi)滯現象(xiang)。機(ji)(ji)(ji)(ji)(ji)械(xie)(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)雖然只能(neng)提(ti)升約10%20%的(de)(de)(de)(de)動力輸出(chu)，但平(ping)順連續性是渦(wo)輪增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)發(fa)動機(ji)(ji)(ji)(ji)(ji)所(suo)不(bu)及的(de)(de)(de)(de)。

廢氣(qi)渦輪增壓

利用(yong)發(fa)動機(ji)廢(fei)氣(qi)(qi)(qi)能(neng)(neng)量(liang)(liang)驅動渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)增壓(ya)(ya)器(qi)，稱(cheng)為(wei)廢(fei)氣(qi)(qi)(qi)渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)增壓(ya)(ya)（簡稱(cheng)渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)增壓(ya)(ya)），如(ru)圖所示是廢(fei)氣(qi)(qi)(qi)渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)增壓(ya)(ya)系統。廢(fei)氣(qi)(qi)(qi)渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)增壓(ya)(ya)的(de)特點是在(zai)渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)增壓(ya)(ya)器(qi)和(he)發(fa)動機(ji)之間(jian)沒(mei)有機(ji)械(xie)連接。它(ta)們之間(jian)靠氣(qi)(qi)(qi)路(lu)相(xiang)通(tong)。因為(wei)壓(ya)(ya)氣(qi)(qi)(qi)機(ji)消耗的(de)功(gong)是渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)從廢(fei)氣(qi)(qi)(qi)中回收的(de)一(yi)部(bu)分能(neng)(neng)量(liang)(liang)，所以渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)增壓(ya)(ya)發(fa)動機(ji)不僅可以增加(jia)發(fa)動機(ji)的(de)功(gong)率(lv)，而(er)且可以提高其熱效率(lv)，降(jiang)低燃油(you)消耗率(lv)。如(ru)果在(zai)轎車(che)尾部(bu)看到(dao)Turbo或(huo)者T的(de)標(biao)識，即表明該(gai)車(che)采(cai)用(yong)的(de)發(fa)動機(ji)是渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)增壓(ya)(ya)的(de)。渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)增壓(ya)(ya)器(qi)實際上(shang)是臺空(kong)(kong)氣(qi)(qi)(qi)壓(ya)(ya)縮機(ji)，它(ta)是利用(yong)發(fa)動機(ji)排出的(de)廢(fei)氣(qi)(qi)(qi)慣性推動渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)，渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)又帶動同軸的(de)葉輪(lun)(lun)壓(ya)(ya)縮由空(kong)(kong)氣(qi)(qi)(qi)濾(lv)清器(qi)管道送來(lai)的(de)空(kong)(kong)氣(qi)(qi)(qi)，使空(kong)(kong)氣(qi)(qi)(qi)增壓(ya)(ya)后進(jin)入氣(qi)(qi)(qi)缸。當發(fa)動機(ji)轉(zhuan)(zhuan)速(su)提高，廢(fei)氣(qi)(qi)(qi)排出速(su)度與(yu)渦(wo)(wo)(wo)(wo)(wo)(wo)(wo)(wo)輪(lun)(lun)轉(zhuan)(zhuan)速(su)也同步提高，葉輪(lun)(lun)就壓(ya)(ya)縮更(geng)(geng)多的(de)空(kong)(kong)氣(qi)(qi)(qi)進(jin)入氣(qi)(qi)(qi)缸，空(kong)(kong)氣(qi)(qi)(qi)的(de)壓(ya)(ya)力和(he)密度增大(da)可以燃燒更(geng)(geng)多的(de)燃油(you)，相(xiang)應增加(jia)油(you)量(liang)(liang)和(he)調整一(yi)下(xia)發(fa)動機(ji)的(de)轉(zhuan)(zhuan)速(su)，就可以增加(jia)發(fa)動機(ji)的(de)輸(shu)出功(gong)率(lv)。