汽(qi)車(che)(che)要(yao)(yao)跑得快，就必(bi)須要(yao)(yao)有(you)強(qiang)勁的(de)動(dong)力。目前汽(qi)車(che)(che)的(de)動(dong)力系(xi)統(tong)可粗分為(wei)(wei)自然進氣(qi)(qi)系(xi)統(tong)及增(zeng)(zeng)壓進氣(qi)(qi)系(xi)統(tong)兩大(da)(da)類。在歐(ou)洲跑車(che)(che)中，除了寶(bao)馬汽(qi)車(che)(che)公司(si)依然堅持使(shi)用(yong)自然進氣(qi)(qi)發(fa)動(dong)機外(wai)，其他各汽(qi)車(che)(che)公司(si)為(wei)(wei)了提升車(che)(che)輛的(de)動(dong)力性能(neng)，紛紛采用(yong)增(zeng)(zeng)壓系(xi)統(tong)，例(li)如：奔(ben)馳(chi)跑車(che)(che)使(shi)用(yong)機械(xie)增(zeng)(zeng)壓系(xi)統(tong)，紳寶(bao)汽(qi)車(che)(che)則為(wei)(wei)渦(wo)輪增(zeng)(zeng)壓的(de)開山鼻祖。近(jin)年日系(xi)汽(qi)車(che)(che)也開始大(da)(da)量采用(yong)渦(wo)輪增(zeng)(zeng)壓技術(shu)。自然進氣(qi)(qi)系(xi)統(tong)沒有(you)安(an)裝(zhuang)任何形式的(de)增(zeng)(zeng)壓器，只是(shi)利用(yong)活塞下行所(suo)產(chan)生的(de)負(fu)壓來(lai)吸進混合氣(qi)(qi)。雖然自然進氣(qi)(qi)系(xi)統(tong)通(tong)過可變氣(qi)(qi)門(men)正時(shi)系(xi)統(tong)能(neng)夠得到較大(da)(da)的(de)馬力輸出(chu)，但動(dong)力的(de)提升很(hen)有(you)限(xian)。為(wei)(wei)了有(you)效(xiao)增(zeng)(zeng)加(jia)發(fa)動(dong)機的(de)輸出(chu)功率，采用(yong)增(zeng)(zeng)壓系(xi)統(tong)可說是(shi)最(zui)有(you)效(xiao)的(de)方(fang)式。

最常見(jian)的(de)發動機增壓系統(tong)有機械增壓與廢(fei)氣渦輪增壓兩種(zhong)。

機械增壓

發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)以機(ji)械(xie)方(fang)式驅(qu)動(dong)(dong)(dong)(dong)機(ji)械(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)進行增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)，稱為機(ji)械(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)。當發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)采(cai)(cai)用機(ji)械(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)時，通(tong)常由發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)曲(qu)軸通(tong)過齒輪(lun)驅(qu)動(dong)(dong)(dong)(dong)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)。增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)一(yi)般采(cai)(cai)用離心式或(huo)羅茨壓(ya)(ya)(ya)(ya)(ya)(ya)氣(qi)機(ji)，個(ge)別的(de)采(cai)(cai)用螺桿式壓(ya)(ya)(ya)(ya)(ya)(ya)氣(qi)機(ji)。近年來，在(zai)國外也開(kai)始(shi)采(cai)(cai)用新型(xing)的(de)機(ji)械(xie)渦旋(xuan)式增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)。因為驅(qu)動(dong)(dong)(dong)(dong)壓(ya)(ya)(ya)(ya)(ya)(ya)氣(qi)機(ji)消(xiao)耗(hao)了(le)發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)一(yi)定(ding)的(de)輸(shu)出功率(lv)(lv)，所以機(ji)械(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)的(de)熱效率(lv)(lv)不一(yi)定(ding)得(de)到改(gai)善，有(you)時反而比非增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)內燃(ran)機(ji)還(huan)低(di)些。選(xuan)擇增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)時，首先要(yao)保證能(neng)(neng)達到所要(yao)求(qiu)(qiu)的(de)平均有(you)效壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)，其次要(yao)獲得(de)盡可能(neng)(neng)低(di)的(de)燃(ran)油消(xiao)耗(hao)率(lv)(lv)。擔這兩個(ge)要(yao)求(qiu)(qiu)對于機(ji)械(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)來說常常是相互矛盾的(de)。如果追求(qiu)(qiu)平均有(you)效壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)，則(ze)必然導(dao)致(zhi)機(ji)械(xie)效率(lv)(lv)降(jiang)低(di)，燃(ran)油消(xiao)耗(hao)率(lv)(lv)升高。因此，增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)值(zhi)的(de)選(xuan)取應在(zai)功率(lv)(lv)和燃(ran)油消(xiao)耗(hao)率(lv)(lv)兩者(zhe)之間(jian)尋求(qiu)(qiu)最佳(jia)的(de)妥協方(fang)案。機(ji)械(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)系統目(mu)前在(zai)歐洲車(che)上用得(de)較普遍。由于機(ji)械(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)的(de)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)機(ji)是在(zai)曲(qu)軸的(de)帶動(dong)(dong)(dong)(dong)下持續地運轉，因此不動(dong)(dong)(dong)(dong)產(chan)生(sheng)像(xiang)渦輪(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)的(de)渦輪(lun)遲滯現象(xiang)。機(ji)械(xie)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)雖然只能(neng)(neng)提升約(yue)10%20%的(de)動(dong)(dong)(dong)(dong)力(li)(li)輸(shu)出，但平順連續性是渦輪(lun)增(zeng)(zeng)(zeng)(zeng)壓(ya)(ya)(ya)(ya)(ya)(ya)發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)所不及的(de)。

廢氣渦輪(lun)增(zeng)壓(ya)

利用(yong)發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)廢(fei)(fei)氣(qi)(qi)(qi)(qi)(qi)能量(liang)驅動(dong)(dong)(dong)(dong)渦(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)器(qi)，稱為廢(fei)(fei)氣(qi)(qi)(qi)(qi)(qi)渦(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)（簡(jian)稱渦(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)），如圖所示是(shi)廢(fei)(fei)氣(qi)(qi)(qi)(qi)(qi)渦(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)系統。廢(fei)(fei)氣(qi)(qi)(qi)(qi)(qi)渦(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)的(de)(de)特(te)點是(shi)在渦(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)器(qi)和(he)發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)之間沒有機(ji)械(xie)連接。它們(men)之間靠氣(qi)(qi)(qi)(qi)(qi)路相通。因(yin)為壓(ya)(ya)氣(qi)(qi)(qi)(qi)(qi)機(ji)消耗(hao)的(de)(de)功(gong)是(shi)渦(wo)輪(lun)(lun)從廢(fei)(fei)氣(qi)(qi)(qi)(qi)(qi)中回收的(de)(de)一部(bu)(bu)分能量(liang)，所以渦(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)不僅可(ke)以增(zeng)(zeng)(zeng)加發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)的(de)(de)功(gong)率(lv)(lv)(lv)，而且可(ke)以提(ti)高其熱效率(lv)(lv)(lv)，降低燃油消耗(hao)率(lv)(lv)(lv)。如果在轎車尾部(bu)(bu)看到Turbo或者T的(de)(de)標識(shi)，即(ji)表(biao)明該車采用(yong)的(de)(de)發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)是(shi)渦(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)的(de)(de)。渦(wo)輪(lun)(lun)增(zeng)(zeng)(zeng)壓(ya)(ya)器(qi)實(shi)際上(shang)是(shi)臺空(kong)(kong)氣(qi)(qi)(qi)(qi)(qi)壓(ya)(ya)縮機(ji)，它是(shi)利用(yong)發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)排(pai)出(chu)的(de)(de)廢(fei)(fei)氣(qi)(qi)(qi)(qi)(qi)慣性推動(dong)(dong)(dong)(dong)渦(wo)輪(lun)(lun)，渦(wo)輪(lun)(lun)又(you)帶動(dong)(dong)(dong)(dong)同軸的(de)(de)葉輪(lun)(lun)壓(ya)(ya)縮由空(kong)(kong)氣(qi)(qi)(qi)(qi)(qi)濾清器(qi)管道送來的(de)(de)空(kong)(kong)氣(qi)(qi)(qi)(qi)(qi)，使(shi)空(kong)(kong)氣(qi)(qi)(qi)(qi)(qi)增(zeng)(zeng)(zeng)壓(ya)(ya)后進(jin)入氣(qi)(qi)(qi)(qi)(qi)缸。當發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)轉(zhuan)速(su)提(ti)高，廢(fei)(fei)氣(qi)(qi)(qi)(qi)(qi)排(pai)出(chu)速(su)度(du)與渦(wo)輪(lun)(lun)轉(zhuan)速(su)也同步提(ti)高，葉輪(lun)(lun)就(jiu)(jiu)壓(ya)(ya)縮更多(duo)(duo)的(de)(de)空(kong)(kong)氣(qi)(qi)(qi)(qi)(qi)進(jin)入氣(qi)(qi)(qi)(qi)(qi)缸，空(kong)(kong)氣(qi)(qi)(qi)(qi)(qi)的(de)(de)壓(ya)(ya)力(li)和(he)密度(du)增(zeng)(zeng)(zeng)大(da)可(ke)以燃燒(shao)更多(duo)(duo)的(de)(de)燃油，相應增(zeng)(zeng)(zeng)加油量(liang)和(he)調(diao)整一下發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)的(de)(de)轉(zhuan)速(su)，就(jiu)(jiu)可(ke)以增(zeng)(zeng)(zeng)加發(fa)(fa)(fa)(fa)動(dong)(dong)(dong)(dong)機(ji)的(de)(de)輸(shu)出(chu)功(gong)率(lv)(lv)(lv)。