汽車(chē)發(fā)動(dòng)機(jī)冷卻系統(tǒng)

1、 汽車(chē)構(gòu)造 學(xué)習(xí)內(nèi)容 掌握程度 冷卻系統(tǒng)的功用及組成 了解 水冷系統(tǒng)主要部件的構(gòu)造 掌握 節(jié)溫器的工作原理 掌握 第七章 發(fā)動(dòng)機(jī)冷卻系統(tǒng) Engine Cooling System 汽車(chē)構(gòu)造第一節(jié) 冷卻系統(tǒng)的功用及功用1 功用 使發(fā)動(dòng)機(jī)在所有工況下都保持在適當(dāng)?shù)臏囟确秶鷥?nèi)n防止發(fā)動(dòng)機(jī)過(guò)熱n防止發(fā)動(dòng)機(jī)過(guò)冷n冷起動(dòng)之后，保證發(fā)機(jī)迅速升溫 汽車(chē)構(gòu)造冷卻不足與冷卻過(guò)度 冷卻不足溫度過(guò)高n零部件熱損傷、配合間隙異常n機(jī)油粘度下降或變質(zhì)，喪失正常功能n充氣效率下降，功率降低，排放惡化等 冷卻過(guò)度溫度過(guò)低n機(jī)油粘度大，功率損耗增加n傳熱損失大，熱效率降低n零部件穴蝕等 汽車(chē)構(gòu)造運(yùn)行溫度對(duì)油耗的影響 汽車(chē)構(gòu)造

2、冷卻系統(tǒng)分類(lèi) 汽車(chē)構(gòu)造2 水冷系統(tǒng)的組成 汽車(chē)構(gòu)造 汽車(chē)構(gòu)造 The head of the engine also has large coolant passageways. 汽車(chē)構(gòu)造水冷系統(tǒng)視頻演示 汽車(chē)構(gòu)造冷卻液的循環(huán)路徑 水泵機(jī)體水套節(jié)溫器增壓, 分水管缸蓋水套吸熱,向上吸熱散熱器小循環(huán)小循環(huán)熱水降溫的水 汽車(chē)構(gòu)造3 冷卻液組成 水防凍劑（乙二醇）作用 防止結(jié)冰，提高沸點(diǎn) 含有防銹劑和泡沫抑制劑例子50乙二醇 冰點(diǎn)：35.5度 沸點(diǎn)：103度 汽車(chē)構(gòu)造冷卻液視頻演示 汽車(chē)構(gòu)造第二節(jié) 水冷系統(tǒng)主要部件的構(gòu)造散熱器 Radiator冷卻風(fēng)扇 Fan節(jié)溫器 Thermostat水泵 Pum

3、p變速器機(jī)油冷卻器 Transmission Oil Cooler 汽車(chē)構(gòu)造1 散熱器1.1 結(jié)構(gòu) 進(jìn)水室 出水室 散熱器芯 汽車(chē)構(gòu)造 按散熱器中冷卻液的流向分類(lèi) 汽車(chē)構(gòu)造散熱器芯的結(jié)構(gòu)形式 汽車(chē)構(gòu)造散熱器視頻演示 汽車(chē)構(gòu)造1.2 散熱器蓋組成閉式水冷系提高沸點(diǎn)減少冷卻液外溢及蒸發(fā)損失 汽車(chē)構(gòu)造散熱器蓋視頻演示 汽車(chē)構(gòu)造1.3 補(bǔ)償水桶 汽車(chē)構(gòu)造1.4 散熱器百葉窗功用功用 通過(guò)調(diào)節(jié)改變吹過(guò)散熱器的空氣流量來(lái)調(diào)節(jié)發(fā)動(dòng)機(jī)的冷通過(guò)調(diào)節(jié)改變吹過(guò)散熱器的空氣流量來(lái)調(diào)節(jié)發(fā)動(dòng)機(jī)的冷卻強(qiáng)度，以保證發(fā)動(dòng)機(jī)經(jīng)常在適當(dāng)?shù)臏囟确秶鷥?nèi)工作。卻強(qiáng)度，以保證發(fā)動(dòng)機(jī)經(jīng)常在適當(dāng)?shù)臏囟确秶鷥?nèi)工作?？諝飧卓諝飧卓諝鈮嚎s機(jī)空氣壓縮

4、機(jī)感溫器感溫器調(diào)整桿調(diào)整桿 汽車(chē)構(gòu)造2 冷卻風(fēng)扇 2.1 風(fēng)扇的功用與結(jié)構(gòu) 汽車(chē)構(gòu)造電動(dòng)風(fēng)扇(electronic fan) 汽車(chē)構(gòu)造冷卻風(fēng)扇視頻演示 汽車(chē)構(gòu)造2.2 硅油風(fēng)扇離合器 汽車(chē)構(gòu)造實(shí)物展示 汽車(chē)構(gòu)造3.1 蠟式節(jié)溫器功用 控制冷卻液流動(dòng)路徑的閥門(mén)結(jié)構(gòu) 85度時(shí)，節(jié)溫器開(kāi)始打開(kāi) 105度時(shí)，節(jié)溫器閥全開(kāi)，7mm 汽車(chē)構(gòu)造3.2 膨脹筒式節(jié)溫器 汽車(chē)構(gòu)造小循環(huán)工作狀態(tài) 汽車(chē)構(gòu)造混合循環(huán)工作狀態(tài) 汽車(chē)構(gòu)造大循環(huán)工作狀態(tài) 汽車(chē)構(gòu)造節(jié)溫器位置布置 氣缸蓋出水管路中缺點(diǎn) 節(jié)溫器振蕩改進(jìn) 散熱器出水管路中 汽車(chē)構(gòu)造節(jié)溫器視頻演示 汽車(chē)構(gòu)造4 水泵功用 對(duì)冷卻液加壓，保證其在冷卻系統(tǒng)中循環(huán)流動(dòng) 汽

5、車(chē)構(gòu)造水泵工作視頻演示 汽車(chē)構(gòu)造 汽車(chē)構(gòu)造5 探討：普通冷卻系統(tǒng)存在的問(wèn)題節(jié)溫器 節(jié)流損失大，不可靠，效率低，調(diào)節(jié)不夠準(zhǔn)確冷卻風(fēng)扇和水泵 由發(fā)動(dòng)機(jī)曲軸驅(qū)動(dòng)，所謂的轉(zhuǎn)速調(diào)節(jié)不能滿(mǎn)足實(shí)際散熱要求，而且皮帶傳動(dòng)效率低。各部件動(dòng)作互不聯(lián)系，效率低 汽車(chē)構(gòu)造6 智能型冷卻系統(tǒng)可調(diào)流量水泵可調(diào)轉(zhuǎn)速風(fēng)扇用比例控制閥替代節(jié)溫器系統(tǒng)集成控制 汽車(chē)構(gòu)造6.1可調(diào)流量水泵 汽車(chē)構(gòu)造6.2 可調(diào)轉(zhuǎn)速風(fēng)扇 汽車(chē)構(gòu)造6.3 電子閥(替代節(jié)溫器) 汽車(chē)構(gòu)造6.4 活塞溫度傳感器 汽車(chē)構(gòu)造7 DANA公司智能冷卻系統(tǒng) 汽車(chē)構(gòu)造第三節(jié) 風(fēng)冷系統(tǒng) 汽車(chē)構(gòu)造 汽車(chē)構(gòu)造 How Car Cooling Systems Work Al

6、though gasoline engines have improved a lot, they are still not very efficient at turning chemical energy into mechanical power. Most of the energy in the gasoline (perhaps 70%) is converted into heat, and it is the job of the cooling system to take care of that heat. The primary job of the cooling

7、system is to keep the engine from overheating by transferring this heat to the air, but the cooling system also has several other important jobs. Diagram of a cooling system: how the plumbing is connectedThe engine in your car runs best at a fairly high temperature. When the engine is cold, componen

8、ts wear out faster, and the engine is less efficient and emits more pollution. So another important job of the cooling system is to allow the engine to heat up as quickly as possible, and then to keep the engine at a constant temperature. 汽車(chē)構(gòu)造 FanLike the thermostat, the cooling fan has to be contro

9、lled so that it allows the engine to maintain a constant temperature. Front-wheel drive cars have electric fans because the engine is usually mounted transversely, meaning the output of the engine points toward the side of the car. The fans are controlled either with a thermostatic switch or by the

10、engine computer, and they turn on when the temperature of the coolant goes above a set point. They turn back off when the temperature drops below that point. Rear-wheel drive cars with longitudinal engines usually have engine-driven cooling fans. These fans have a thermostatically controlled viscous clutch. This clutch is positioned at the hub of the fan, in th