汽車(che)(che)要跑得(de)快，就必(bi)須要有強勁(jing)的(de)(de)動(dong)力(li)。目前汽車(che)(che)的(de)(de)動(dong)力(li)系(xi)(xi)(xi)統(tong)(tong)可粗(cu)分為(wei)自然進(jin)氣(qi)系(xi)(xi)(xi)統(tong)(tong)及增(zeng)(zeng)(zeng)壓(ya)進(jin)氣(qi)系(xi)(xi)(xi)統(tong)(tong)兩大(da)類。在歐洲跑車(che)(che)中，除了(le)寶馬汽車(che)(che)公司依然堅持使用(yong)(yong)自然進(jin)氣(qi)發(fa)(fa)動(dong)機外(wai)，其他各汽車(che)(che)公司為(wei)了(le)提升車(che)(che)輛的(de)(de)動(dong)力(li)性(xing)能，紛紛采(cai)用(yong)(yong)增(zeng)(zeng)(zeng)壓(ya)系(xi)(xi)(xi)統(tong)(tong)，例如：奔馳跑車(che)(che)使用(yong)(yong)機械增(zeng)(zeng)(zeng)壓(ya)系(xi)(xi)(xi)統(tong)(tong)，紳寶汽車(che)(che)則為(wei)渦輪增(zeng)(zeng)(zeng)壓(ya)的(de)(de)開(kai)山(shan)鼻祖。近年(nian)日系(xi)(xi)(xi)汽車(che)(che)也開(kai)始大(da)量采(cai)用(yong)(yong)渦輪增(zeng)(zeng)(zeng)壓(ya)技術。自然進(jin)氣(qi)系(xi)(xi)(xi)統(tong)(tong)沒有安裝任(ren)何(he)形式(shi)的(de)(de)增(zeng)(zeng)(zeng)壓(ya)器，只是利用(yong)(yong)活塞下行所產生(sheng)的(de)(de)負(fu)壓(ya)來吸進(jin)混合(he)氣(qi)。雖(sui)然自然進(jin)氣(qi)系(xi)(xi)(xi)統(tong)(tong)通過可變氣(qi)門正時系(xi)(xi)(xi)統(tong)(tong)能夠得(de)到較大(da)的(de)(de)馬力(li)輸(shu)出(chu)，但(dan)動(dong)力(li)的(de)(de)提升很有限(xian)。為(wei)了(le)有效增(zeng)(zeng)(zeng)加發(fa)(fa)動(dong)機的(de)(de)輸(shu)出(chu)功率，采(cai)用(yong)(yong)增(zeng)(zeng)(zeng)壓(ya)系(xi)(xi)(xi)統(tong)(tong)可說是最有效的(de)(de)方式(shi)。

最(zui)常見的發動機(ji)增(zeng)壓(ya)系統有機(ji)械增(zeng)壓(ya)與(yu)廢氣渦輪增(zeng)壓(ya)兩種。

機械增壓

發動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)(ji)以(yi)機(ji)(ji)(ji)(ji)械(xie)(xie)(xie)方式驅(qu)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)器(qi)(qi)進(jin)行增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)，稱為機(ji)(ji)(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)。當發動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)(ji)采(cai)用(yong)機(ji)(ji)(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)時，通(tong)(tong)常由發動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)(ji)曲軸(zhou)通(tong)(tong)過(guo)齒(chi)輪驅(qu)動(dong)(dong)(dong)(dong)(dong)(dong)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)器(qi)(qi)。增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)器(qi)(qi)一般采(cai)用(yong)離(li)心式或羅(luo)茨壓(ya)(ya)(ya)氣(qi)機(ji)(ji)(ji)(ji)，個(ge)別的采(cai)用(yong)螺桿(gan)式壓(ya)(ya)(ya)氣(qi)機(ji)(ji)(ji)(ji)。近(jin)年(nian)來(lai)(lai)，在(zai)國外也開始采(cai)用(yong)新型的機(ji)(ji)(ji)(ji)械(xie)(xie)(xie)渦(wo)旋式增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)器(qi)(qi)。因為驅(qu)動(dong)(dong)(dong)(dong)(dong)(dong)壓(ya)(ya)(ya)氣(qi)機(ji)(ji)(ji)(ji)消(xiao)耗(hao)(hao)了發動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)(ji)一定的輸出(chu)功(gong)率(lv)(lv)，所(suo)以(yi)機(ji)(ji)(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)發動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)(ji)的熱效(xiao)率(lv)(lv)不(bu)一定得(de)到(dao)改善，有(you)時反(fan)而比非增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)內(nei)燃(ran)機(ji)(ji)(ji)(ji)還低些。選擇增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)壓(ya)(ya)(ya)力(li)時，首(shou)先要(yao)保(bao)證能(neng)達到(dao)所(suo)要(yao)求(qiu)(qiu)的平(ping)均(jun)有(you)效(xiao)壓(ya)(ya)(ya)力(li)，其次要(yao)獲得(de)盡可能(neng)低的燃(ran)油消(xiao)耗(hao)(hao)率(lv)(lv)。擔這兩個(ge)要(yao)求(qiu)(qiu)對于(yu)機(ji)(ji)(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)來(lai)(lai)說(shuo)常常是(shi)相互矛盾的。如果追求(qiu)(qiu)平(ping)均(jun)有(you)效(xiao)壓(ya)(ya)(ya)力(li)，則必然導致機(ji)(ji)(ji)(ji)械(xie)(xie)(xie)效(xiao)率(lv)(lv)降低，燃(ran)油消(xiao)耗(hao)(hao)率(lv)(lv)升(sheng)高。因此，增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)壓(ya)(ya)(ya)力(li)值的選取(qu)應(ying)在(zai)功(gong)率(lv)(lv)和燃(ran)油消(xiao)耗(hao)(hao)率(lv)(lv)兩者(zhe)之間(jian)尋求(qiu)(qiu)最(zui)佳的妥(tuo)協(xie)方案。機(ji)(ji)(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)系統目前在(zai)歐洲車上(shang)用(yong)得(de)較(jiao)普遍。由于(yu)機(ji)(ji)(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)的增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)機(ji)(ji)(ji)(ji)是(shi)在(zai)曲軸(zhou)的帶動(dong)(dong)(dong)(dong)(dong)(dong)下持續地運(yun)轉，因此不(bu)動(dong)(dong)(dong)(dong)(dong)(dong)產生像渦(wo)輪增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)的渦(wo)輪遲(chi)滯現象。機(ji)(ji)(ji)(ji)械(xie)(xie)(xie)增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)雖然只能(neng)提(ti)升(sheng)約10%20%的動(dong)(dong)(dong)(dong)(dong)(dong)力(li)輸出(chu)，但平(ping)順連續性是(shi)渦(wo)輪增(zeng)(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)發動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)(ji)所(suo)不(bu)及的。

廢氣(qi)渦(wo)輪增壓(ya)

利用發(fa)(fa)動(dong)(dong)機(ji)(ji)廢(fei)氣(qi)(qi)能量(liang)(liang)驅動(dong)(dong)渦(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)器(qi)(qi)，稱為廢(fei)氣(qi)(qi)渦(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)（簡稱渦(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)），如(ru)圖所示是(shi)廢(fei)氣(qi)(qi)渦(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)系統。廢(fei)氣(qi)(qi)渦(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)的(de)(de)特點是(shi)在渦(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)器(qi)(qi)和(he)發(fa)(fa)動(dong)(dong)機(ji)(ji)之間(jian)沒有機(ji)(ji)械連接。它(ta)們之間(jian)靠氣(qi)(qi)路相(xiang)通。因為壓(ya)(ya)氣(qi)(qi)機(ji)(ji)消(xiao)耗的(de)(de)功是(shi)渦(wo)(wo)輪(lun)(lun)(lun)從(cong)廢(fei)氣(qi)(qi)中回收的(de)(de)一部分能量(liang)(liang)，所以(yi)渦(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)發(fa)(fa)動(dong)(dong)機(ji)(ji)不(bu)僅可以(yi)增(zeng)(zeng)(zeng)(zeng)加發(fa)(fa)動(dong)(dong)機(ji)(ji)的(de)(de)功率(lv)，而且可以(yi)提高(gao)其熱效率(lv)，降低燃油(you)消(xiao)耗率(lv)。如(ru)果(guo)在轎車尾(wei)部看到Turbo或者(zhe)T的(de)(de)標(biao)識，即(ji)表明(ming)該(gai)車采(cai)用的(de)(de)發(fa)(fa)動(dong)(dong)機(ji)(ji)是(shi)渦(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)的(de)(de)。渦(wo)(wo)輪(lun)(lun)(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)器(qi)(qi)實(shi)際上是(shi)臺空(kong)(kong)氣(qi)(qi)壓(ya)(ya)縮機(ji)(ji)，它(ta)是(shi)利用發(fa)(fa)動(dong)(dong)機(ji)(ji)排出(chu)的(de)(de)廢(fei)氣(qi)(qi)慣性推動(dong)(dong)渦(wo)(wo)輪(lun)(lun)(lun)，渦(wo)(wo)輪(lun)(lun)(lun)又帶(dai)動(dong)(dong)同軸的(de)(de)葉(xie)輪(lun)(lun)(lun)壓(ya)(ya)縮由空(kong)(kong)氣(qi)(qi)濾清器(qi)(qi)管道(dao)送來的(de)(de)空(kong)(kong)氣(qi)(qi)，使空(kong)(kong)氣(qi)(qi)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)后進入氣(qi)(qi)缸(gang)。當發(fa)(fa)動(dong)(dong)機(ji)(ji)轉(zhuan)速提高(gao)，廢(fei)氣(qi)(qi)排出(chu)速度與渦(wo)(wo)輪(lun)(lun)(lun)轉(zhuan)速也同步提高(gao)，葉(xie)輪(lun)(lun)(lun)就壓(ya)(ya)縮更多的(de)(de)空(kong)(kong)氣(qi)(qi)進入氣(qi)(qi)缸(gang)，空(kong)(kong)氣(qi)(qi)的(de)(de)壓(ya)(ya)力和(he)密度增(zeng)(zeng)(zeng)(zeng)大可以(yi)燃燒更多的(de)(de)燃油(you)，相(xiang)應增(zeng)(zeng)(zeng)(zeng)加油(you)量(liang)(liang)和(he)調整一下(xia)發(fa)(fa)動(dong)(dong)機(ji)(ji)的(de)(de)轉(zhuan)速，就可以(yi)增(zeng)(zeng)(zeng)(zeng)加發(fa)(fa)動(dong)(dong)機(ji)(ji)的(de)(de)輸出(chu)功率(lv)。