制動液的分類及選購標準
制(zhi)動(dong)(dong)液(ye)俗稱“剎車(che)(che)油”,它是(shi)機動(dong)(dong)車(che)(che)液(ye)壓(ya)制(zhi)動(dong)(dong)系(xi)統中傳遞壓(ya)力(li)、制(zhi)止(zhi)車(che)(che)輪(lun)轉動(dong)(dong)的(de)(de)介質(zhi),目前,90%的(de)(de)車(che)(che)輛(liang)均采用液(ye)壓(ya)制(zhi)動(dong)(dong)系(xi)統。因(yin)其特殊(shu)性,它必須要(yao)有(you)適(shi)(shi)宜的(de)(de)高溫粘度(du)和良(liang)好(hao)(hao)的(de)(de)低溫流(liu)動(dong)(dong)性;有(you)良(liang)好(hao)(hao)的(de)(de)化學穩定性;有(you)較高的(de)(de)平衡回流(liu)沸點;有(you)較低的(de)(de)吸濕(shi)性;有(you)良(liang)好(hao)(hao)的(de)(de)橡膠適(shi)(shi)應(ying)性;有(you)良(liang)好(hao)(hao)的(de)(de)金屬抗腐(fu)蝕(shi)性。制(zhi)動(dong)(dong)液(ye)既然重(zhong)要(yao),那什么(me)時(shi)候更換(huan)、怎么(me)選擇合適(shi)(shi)的(de)(de)型號以及要(yao)注意哪些(xie)問題也是(shi)許多(duo)車(che)(che)友急于想了解(jie)的(de)(de)。
制動液的分類
由于配制(zhi)(zhi)的(de)原料(liao)不同,制(zhi)(zhi)動(dong)液(ye)(ye)的(de)種類比較多,目前大體上(shang)分(fen)為3種類型(xing):醇(chun)(chun)型(xing)、礦物油(you)型(xing)和合成型(xing)。其中醇(chun)(chun)型(xing)制(zhi)(zhi)動(dong)液(ye)(ye)有醇(chun)(chun)型(xing)1號(蓖(bi)麻(ma)油(you)+乙醇(chun)(chun))和醇(chun)(chun)型(xing)3號(蓖(bi)麻(ma)油(you)+丁(ding)醇(chun)(chun)),醇(chun)(chun)型(xing)制(zhi)(zhi)動(dong)液(ye)(ye)工藝簡單(dan)、潤滑性(xing)好且價格低廉,但在炎熱季節使(shi)用(yong)(yong)時(shi)易產生(sheng)氣(qi)阻,在嚴寒地區的(de)冬季使(shi)用(yong)(yong)時(shi)會變稠分(fen)層,使(shi)制(zhi)(zhi)動(dong)沉(chen)重,甚至失靈,故已(yi)被淘(tao)汰。
礦(kuang)(kuang)物(wu)油型(xing)(xing)制(zhi)動(dong)(dong)液(ye)是以(yi)精制(zhi)的輕柴油餾分經深(shen)度脫臘得到的C12~C19異構烷烴及(ji)烷烴組分經添(tian)加稠化劑(ji)(ji)、抗氧劑(ji)(ji)和(he)助劑(ji)(ji)調合(he)而(er)成。按(an)運動(dong)(dong)粘度分為(wei)7號和(he)9號兩(liang)種類(lei)型(xing)(xing)。礦(kuang)(kuang)物(wu)型(xing)(xing)制(zhi)動(dong)(dong)液(ye)的溫度適(shi)應(ying)范(fan)圍很(hen)寬,可以(yi)從-50℃~150℃,低溫流(liu)動(dong)(dong)性(xing)和(he)潤滑性(xing)較好,對金屬無腐(fu)蝕作(zuo)用(yong)(yong)。但對制(zhi)動(dong)(dong)系(xi)統(tong)的橡膠部件(jian)(jian)(如皮碗)有溶解作(zuo)用(yong)(yong),如使用(yong)(yong)這(zhe)種類(lei)型(xing)(xing)的制(zhi)動(dong)(dong)液(ye),必須換用(yong)(yong)耐礦(kuang)(kuang)物(wu)油的橡膠零件(jian)(jian)。
目(mu)前使用較為普(pu)遍的是(shi)合(he)成(cheng)(cheng)型制(zhi)(zhi)動(dong)(dong)液(ye),它(ta)是(shi)以有機溶劑(ji)中的醇、醚(mi)和酯為基礎,加(jia)入(ru)添加(jia)劑(ji)調(diao)制(zhi)(zhi)而成(cheng)(cheng)。合(he)成(cheng)(cheng)性制(zhi)(zhi)動(dong)(dong)液(ye)的成(cheng)(cheng)分比較復雜,性質差(cha)異很大(da),為此國家頒布(bu)了合(he)成(cheng)(cheng)型制(zhi)(zhi)動(dong)(dong)液(ye)標(biao)準。有1號、4603、4603~1和4604等牌號。4603和4603~l號合(he)成(cheng)(cheng)制(zhi)(zhi)動(dong)(dong)液(ye)適用于各類(lei)載貨汽車的制(zhi)(zhi)動(dong)(dong)系(xi)(xi);4604則適用于高檔轎車和各種汽車的制(zhi)(zhi)動(dong)(dong)系(xi)(xi)。
合成型制(zhi)(zhi)動(dong)(dong)液沸點較高,不(bu)(bu)易產生氣阻;良好的低(di)溫(wen)(wen)流動(dong)(dong)性(xing),不(bu)(bu)因低(di)溫(wen)(wen)而粘度增大、流動(dong)(dong)性(xing)變(bian)差,使制(zhi)(zhi)動(dong)(dong)發硬(ying);吸水性(xing)小,不(bu)(bu)影響沸點和低(di)溫(wen)(wen)流動(dong)(dong)性(xing);良好的化(hua)學穩定性(xing),對金屬有防腐、防銹(xiu)作(zuo)用,不(bu)(bu)易分解變(bian)質而產生沉(chen)淀物;對橡膠(jiao)件的腐蝕和溶脹性(xing)小,以保證(zheng)密(mi)封件不(bu)(bu)會嚴重變(bian)形等。這類制(zhi)(zhi)動(dong)(dong)液在我國各地一年四(si)季均可(ke)使用,因而正逐(zhu)漸成為(wei)通用型制(zhi)(zhi)動(dong)(dong)液。
制動液的質量等級
制(zhi)動(dong)液(ye)與機油一(yi)樣,也有質(zhi)量(liang)等級之分(fen)。國產制(zhi)動(dong)液(ye)的(de)質(zhi)量(liang)等級:國產制(zhi)動(dong)液(ye)根據其平(ping)衡回流、沸點(dian)分(fen)為JG3、JG4、JG5三個質(zhi)量(liang)等級。序號越(yue)大平(ping)衡回流沸點(dian)越(yue)高,高溫抗氣(qi)阻性越(yue)好,行(xing)車制(zhi)動(dong)安全(quan)性越(yue)高。我(wo)國還將合成制(zhi)動(dong)液(ye)分(fen)為:HZY3、HZY4和HZY5。
國(guo)(guo)外制動液的(de)質量(liang)等(deng)(deng)級(ji):美(mei)國(guo)(guo)汽車(che)工程學會(SAE)規(gui)格有(you)SAEJ1704(高溫(wen)地(di)區使用)、SAEJ1703(正(zheng)常)、SAEJ1702(嚴寒(han)地(di)區使用)。另(ling)外美(mei)國(guo)(guo)聯邦機動車(che)輛安全標準規(gui)格分為DOT3、DOT4和DOT5等(deng)(deng),后者(zhe)比前者(zhe)的(de)綜合性能好。DOT3與DOT4的(de)不(bu)同(tong)之處主要在(zai)于沸點不(bu)同(tong),DOT4比DOT3更耐高溫(wen)。DOT3和DOT4級(ji)制動液是以聚二醇為基(ji)礎和乙(yi)二醇及(ji)乙(yi)二醇衍(yan)生(sheng)物(wu)為主的(de)醇醚型合成(cheng)制動液,再加潤滑劑、稀釋劑、防銹劑、橡膠抑(yi)制劑等(deng)(deng)調和而成(cheng),也是各國(guo)(guo)汽車(che)最普遍使用的(de)一種制動液。JG3、JG4、JG5分別(bie)對應DOT3、DOT4、DOT5級(ji)別(bie)。
這里需要給大(da)(da)家(jia)說明一(yi)下的(de)(de)是,目前國內家(jia)用(yong)轎(jiao)車(che)多使(shi)用(yong)合成型制動液,所采用(yong)的(de)(de)標準(zhun)也多以美國聯(lian)邦機動車(che)輛安全標準(zhun)規(gui)格的(de)(de)DOT標準(zhun)為(wei)主。而國標多用(yong)在商(shang)用(yong)車(che)以及貨車(che)等大(da)(da)型車(che)輛的(de)(de)制動液上。
級別
制動液主要特性
對應牌號
推薦使用范圍
JG3
具有良(liang)好的(de)高溫(wen)抗氣阻性能和(he)優良(liang)的(de)低溫(wen)性能
DOT3、HZY3
SAEJ1703
我(wo)國廣(guang)大地區(qu)均可使用
JG4
具有良好的高(gao)溫抗(kang)氣阻性(xing)能和良好的低(di)溫性(xing)能
DOT4、HZY4
SAEJ1704
我國廣大地區均可(ke)使用,適用于制(zhi)動操作時溫度較(jiao)高的轎車
JG5
具有優異的高(gao)溫(wen)抗(kang)氣(qi)阻性能和低(di)溫(wen)性能
DOT5、HZY5
SAEJ1705
有特殊要求的車輛使用制動液的更換和選用
當今汽(qi)(qi)車(che)的設計車(che)速(su)越來越高(gao)、結構越來越緊湊,導致制(zhi)(zhi)動(dong)(dong)(dong)液的工(gong)作溫(wen)度(du)很高(gao)而散熱通(tong)風條(tiao)件較差,因此,對(dui)制(zhi)(zhi)動(dong)(dong)(dong)液的性(xing)能要(yao)求也越來越高(gao)。目前,世界(jie)各(ge)國使(shi)用的制(zhi)(zhi)動(dong)(dong)(dong)液一般(ban)都(dou)是(shi)合成(cheng)制(zhi)(zhi)動(dong)(dong)(dong)液。關(guan)于(yu)制(zhi)(zhi)動(dong)(dong)(dong)液的更換(huan)(huan)周(zhou)期,目前尚無統一規定(ding),通(tong)常是(shi)根據汽(qi)(qi)車(che)生(sheng)產廠商(shang)或制(zhi)(zhi)動(dong)(dong)(dong)液生(sheng)產廠商(shang)規定(ding)的時(shi)(shi)間進(jin)行(xing)(xing)更換(huan)(huan)。制(zhi)(zhi)動(dong)(dong)(dong)液的更換(huan)(huan)周(zhou)期主要(yao)以行(xing)(xing)駛里程(cheng)和(he)使(shi)用時(shi)(shi)間來確定(ding)。一般(ban)使(shi)用低(di)級(ji)別(bie)制(zhi)(zhi)動(dong)(dong)(dong)液的中、低(di)檔(dang)車(che)輛(liang),換(huan)(huan)油周(zhou)期為每年1次(ci)(ci)或者(zhe)2~4萬公里;使(shi)用中、高(gao)級(ji)別(bie)制(zhi)(zhi)動(dong)(dong)(dong)液的中、高(gao)檔(dang)車(che)輛(liang),換(huan)(huan)油周(zhou)期為每兩年1次(ci)(ci)或者(zhe)4~5萬公里;另外在對(dui)制(zhi)(zhi)動(dong)(dong)(dong)系統進(jin)行(xing)(xing)修理(li)和(he)更換(huan)(huan)制(zhi)(zhi)動(dong)(dong)(dong)主缸(gang)、制(zhi)(zhi)動(dong)(dong)(dong)輪缸(gang)的活(huo)塞(sai)、皮碗等(deng)零部件的同時(shi)(shi)需(xu)要(yao)更換(huan)(huan)制(zhi)(zhi)動(dong)(dong)(dong)液。在實(shi)際使(shi)用中,如(ru)果出(chu)現制(zhi)(zhi)動(dong)(dong)(dong)踏板忽輕忽重、制(zhi)(zhi)動(dong)(dong)(dong)皮碗溶脹(zhang)、換(huan)(huan)季時(shi)(shi)(尤(you)其在冬季)出(chu)現制(zhi)(zhi)動(dong)(dong)(dong)無力這些情況就需(xu)要(yao)及(ji)時(shi)(shi)對(dui)制(zhi)(zhi)動(dong)(dong)(dong)液進(jin)行(xing)(xing)更換(huan)(huan)。
對于制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye)選(xuan)(xuan)擇(ze)問題(ti),原則上根(gen)據汽車(che)生(sheng)產(chan)廠家(jia)使(shi)(shi)用(yong)(yong)說(shuo)明(ming)書推薦(jian)的(de)(de)(de)(de)(de)質量(liang)等(deng)級、品(pin)牌(pai)(pai)、型(xing)(xing)(xing)號(hao)(hao)等(deng)進行(xing)選(xuan)(xuan)擇(ze)。按(an)照國標(biao)(biao)或DOT標(biao)(biao)準選(xuan)(xuan)擇(ze)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye)的(de)(de)(de)(de)(de)質量(liang)等(deng)級,盡量(liang)使(shi)(shi)用(yong)(yong)合(he)(he)成(cheng)型(xing)(xing)(xing)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye),并優先選(xuan)(xuan)用(yong)(yong)高等(deng)級的(de)(de)(de)(de)(de);車(che)輛使(shi)(shi)用(yong)(yong)說(shuo)明(ming)書在(zai)給出了(le)標(biao)(biao)準品(pin)牌(pai)(pai)號(hao)(hao)外(wai),一(yi)般還提供了(le)可(ke)供代(dai)(dai)用(yong)(yong)的(de)(de)(de)(de)(de)品(pin)牌(pai)(pai)號(hao)(hao)。用(yong)(yong)戶應(ying)(ying)(ying)盡可(ke)能(neng)選(xuan)(xuan)用(yong)(yong)標(biao)(biao)準品(pin)牌(pai)(pai)號(hao)(hao)的(de)(de)(de)(de)(de)產(chan)品(pin),缺(que)乏(fa)(fa)時(shi)才(cai)(cai)考慮選(xuan)(xuan)用(yong)(yong)代(dai)(dai)用(yong)(yong)品(pin)。如果(guo)(guo)(guo)推薦(jian)的(de)(de)(de)(de)(de)代(dai)(dai)用(yong)(yong)品(pin)牌(pai)(pai)也缺(que)乏(fa)(fa),才(cai)(cai)可(ke)以選(xuan)(xuan)擇(ze)相應(ying)(ying)(ying)等(deng)級的(de)(de)(de)(de)(de)代(dai)(dai)用(yong)(yong)品(pin);對有(you)特殊要求的(de)(de)(de)(de)(de)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)系(xi)(xi)統(tong),應(ying)(ying)(ying)加注特定牌(pai)(pai)號(hao)(hao)的(de)(de)(de)(de)(de)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye)。有(you)的(de)(de)(de)(de)(de)合(he)(he)成(cheng)型(xing)(xing)(xing)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye)溫(wen)度范(fan)圍在(zai)-60℃~60℃之間,低(di)(di)溫(wen)下(xia)(xia)粘度比較小,非常適(shi)合(he)(he)于嚴寒地(di)區(qu)(qu)冬季使(shi)(shi)用(yong)(yong);如果(guo)(guo)(guo)汽車(che)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)系(xi)(xi)統(tong)的(de)(de)(de)(de)(de)橡膠零件是(shi)耐油(you)(you)的(de)(de)(de)(de)(de),應(ying)(ying)(ying)優先選(xuan)(xuan)用(yong)(yong)礦(kuang)物油(you)(you)型(xing)(xing)(xing)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye),它(ta)不受地(di)區(qu)(qu)、季節和(he)車(che)型(xing)(xing)(xing)的(de)(de)(de)(de)(de)限(xian)制(zhi)(zhi)(zhi),潤滑(hua)性好,無腐蝕作(zuo)用(yong)(yong),換(huan)油(you)(you)周期長;但制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)系(xi)(xi)統(tong)橡膠零件不是(shi)耐油(you)(you)的(de)(de)(de)(de)(de),則不能(neng)使(shi)(shi)用(yong)(yong)礦(kuang)物型(xing)(xing)(xing)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye);不同(tong)類(lei)(lei)型(xing)(xing)(xing)的(de)(de)(de)(de)(de)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye)由于成(cheng)分不同(tong),混(hun)合(he)(he)后可(ke)能(neng)發生(sheng)化學反應(ying)(ying)(ying),堵塞制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)系(xi)(xi)統(tong),所以通常不允許混(hun)用(yong)(yong)。一(yi)般相溶(rong)性較好的(de)(de)(de)(de)(de)同(tong)一(yi)類(lei)(lei)型(xing)(xing)(xing)的(de)(de)(de)(de)(de)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye),也不能(neng)混(hun)用(yong)(yong),以防相互(hu)間產(chan)生(sheng)化學反應(ying)(ying)(ying),影響制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)效果(guo)(guo)(guo);選(xuan)(xuan)用(yong)(yong)正規優質產(chan)品(pin),避免使(shi)(shi)用(yong)(yong)質量(liang)低(di)(di)劣產(chan)品(pin)。選(xuan)(xuan)購制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye)時(shi),首先看產(chan)品(pin)說(shuo)明(ming)書或標(biao)(biao)簽上的(de)(de)(de)(de)(de)說(shuo)明(ming),是(shi)什么類(lei)(lei)型(xing)(xing)(xing),有(you)無質量(liang)標(biao)(biao)準和(he)質量(liang)指(zhi)標(biao)(biao),若沒有(you)標(biao)(biao)注這(zhe)些(xie)內容則不能(neng)使(shi)(shi)用(yong)(yong),而只標(biao)(biao)有(you)類(lei)(lei)型(xing)(xing)(xing)的(de)(de)(de)(de)(de)應(ying)(ying)(ying)慎用(yong)(yong)。千萬不要選(xuan)(xuan)用(yong)(yong)國家(jia)早已淘汰(tai)的(de)(de)(de)(de)(de)醇型(xing)(xing)(xing)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye)。合(he)(he)成(cheng)型(xing)(xing)(xing)制(zhi)(zhi)(zhi)動(dong)(dong)(dong)(dong)液(ye)型(xing)(xing)(xing)號(hao)(hao)很多,顏色各異,要注意其質量(liang)指(zhi)標(biao)(biao)中(zhong)的(de)(de)(de)(de)(de)溫(wen)度范(fan)圍,常溫(wen)和(he)低(di)(di)溫(wen)下(xia)(xia)的(de)(de)(de)(de)(de)粘度、透明(ming)度,有(you)無沉(chen)淀和(he)異味。
有ABS裝置的車輛的制動系統產生的摩擦熱比未裝ABS裝置的車高,制動液的惡化變質也可能會相對早地出現,如果在制動液變質的情況下繼續使用,將會使制動主缸、輪缸、油壓控制器等產生損傷、吸濕率增加,使制動力下降。因此,要對裝有ABS裝置車輛的制動液從嚴選用,嚴格遵守汽車制造廠商推薦的更換周期。另外還要根據使用條件,在必要時提前進行更換。有ABS系統的車輛一般都選用DOT4的制動液。盡管DOT5的制動液具有更高的沸點,但是,由于DOT5是硅基制動液.會對橡膠件產生較強的損害。因此。在ABS系統中,一般不選用DOT5的制動液。但是,由于DOT3和DOT4是醇基制動液,具有較強的吸濕性,隨著使用時間的延長,其中的含水量會不斷增多。當制動液中含有較多的水分時,會使制動壓力調節裝置中的精密零件發生銹蝕;在寒冷的氣候條件下,還會使制動液的粘度變大,影響制動液在制動系統中的流動,使制動變得遲緩,從而導致制動距離延長。另外,制動液中的含水量會對制動液的沸點產生非常明顯的影響,發生氣阻現象。DOT3和DOT4制動液一般經過12個月的使用以后其中的含水量為2%,經過18個月的使用以后.其中的含水量平均可達3%。因此建議每12個月更換一次制動液。