[Lung Sir Classroom Ep37] Gasoline, diesel and EV (Subtitles included)｜TopGear Magazine HK Topgearhk 

謝謝支持！

謝謝！

儘管內燃機就快成為歷史，但它對推動人類文明發展是功不可沒的，老衲只剩一囗氣都要將其竅門傳下去。

我覺得內燃機應該唔會成為歷史，最起碼柴油發電機都未會被淘汰

希望龍sir 跟住又 講下 燃油特性 例如點解d 牌子油 添加劑唔同 performance 會唔同 （大陸就95，97） 等車主可以知道入咩油 又平又岩自己架車。

@@sir167龍sir 多謝您!

@@sir167 whilst you're on it, why not do an extra episode talk about synthetic fuels & hydrogen in ICE? Cause if you ask me, the problem was never with the ICE, it was with the fuel that they run on, the cleaner the fuel, the less crap out the back. And yet people just wants to jump to conclusions and ICE ended up taking the blame for something that's really not it's fault IMO. Sooner / later they will realise they've jumped to the WRONG conclusion

謝謝！

摩打要轉數高，係要個motor drive可以俾到大電壓。摩打扭力純睇電流，所以只要電流保持到，扭力係任何轉數都可以一樣高，問題在於摩打有back emf，啫係一個反向既電壓頂返轉頭，而衣個back emf會隨住摩打轉速提高而同時提高，只要摩打轉得越快，back emf就會越高。因為電就好似水流咁由高向低流，啫係會由高電壓向低電壓流，而電流就好似水流咁，電壓差越高就越大，所以如果back emf提高咗，電壓差就會減少令電流都減少，令到摩打係高轉時扭力會減少。而其中一個有效既方法係增加輸入電壓。當然咁係會有上限的，所以先會有個摩打到高轉就會無扭力既現象。

Hybrid + Turbo

@@looking2005 你唔鍾意Hybrid車?

問題是混能車重，

@@lulu9394 因為電池energy density太低了....

世上新人換舊人，未來是屬於你們年輕一代的！👍

咁我要Jel下頭髮，在巴士車尾賣廣告。

感謝支持！

謝謝！

謝謝！

謝謝！

謝謝！

俾個like你👍

謝謝！

謝謝！

謝謝！

老老實實，當年有冇走堂先？😄

謝謝！

謝謝！

謝謝！

謝謝！

謝謝！

謝謝！

謝謝！

謝謝！

謝謝！

我是畢業後很多年後，做了爸爸跟孩子打過韆鞦才悟出來。

謝謝！

謝謝！

謝謝！

不好意思，在下對電單車的認識有限，恐怕令閣下矢望。

Driving4answers呢個RU-vid channel既引掣介紹系列入面有圖文並茂咁好詳細講解呢啲topic, 有空閒時間既話極力推薦去睇下

謝謝！

是的，口徑比衝程大，稱為oversquare 設計，有利高轉。

謝謝！

謝謝！

謝謝！不敢當！

高轉引擎有迷人的魅力，其中valve overlap 設定很關鍵，這話題值得一談。

上課抄筆記，考試背筆記，考完全忘記，好正常😄

那就好！

@@sir167 現在電油也有噴注 好像FSI...TSI...

@@wilsonman8391 對，現在汽油也弄成像柴油的缸內直噴，因此低扭好了，轉速也慢了。

@UC0LymngmozVVP8SME_J92UA 這是個學術很有趣的問題，柴油在常溫下不能氣化，因此汽油車入柴油一定會死火。至於柴油車入汽油，一般認為汽油太易點著，會因為太早點火而破壞引擎，但實際上又不是那麼絕對，英國有車媒做過試驗並拍了片，發現不是想像中死得那麼慘烈，柴油車入了汽車不單止沒爆偈，還能走上一段時間。大家認為汽油容易點著是因為它的閃點（flash point）很低，即使低溫下只有有點火花就會點著，但汽油的燃點（burning point）其實比柴油更高，即是說在沒有火花之下，把汽油和柴油同時加熱，先著火的是柴油，這點是很多人不知道的。但說到底，柴油車入錯汽油最終不能走得遠，是因為供油系統零件的設計，是預計有柴油的潤滑能力幫手，換上汽油零件很快會卡死，同時，若引擎狀態不，局部地區域出現高溫，汽油真的可能會預燃爆震打搞引擎，這種實驗好比砍頭埋牆試下痛唔痛，是十分無聊的。

@@sir167 是的，FSI,SPCCI 都用火花塞點火.

去年我們有兩集講關於turbo，但沒談過supercharger，有機會安排一下。

NA車把最佳入氣和混合渦流調在高轉，低轉扭力便不好，把最佳時機調在低轉，高轉卻上不了影響馬力，turbo或supercharger主動進氣，減少進氣困難，氣多了可以燒多一點況，於是整個工作範圍的扭力加強。

They are both Force Induction Methods Traditionally, the supercharger, driven by the crank of an engine forces more air in at low revs & improves the torque low down on the rev range, but then once the revs got up to speed not only it doesn't help much, it actually starts sapping power, they call it parasitic loss. The Turbocharger on the other hand recycles exhaust gases to spin up the turbine wheel which is on the same axle as the compressor wheel which forces more air in at higher revs, this improves the power at higher rev range, but because you need enough exhaust gases to make the turbine start spinning, at low-very low revs you'd get Turbo Lag. This was why VW made the 1.4TSI all those years ago with supercharger starting the Force Induction work at low revs then the turbo takes over after certain revs, in theory giving you best of both worlds. Over the years with vast improvements to Turbo engines thanks to Saab, Porsche etc. with technology such as low pressure turbo, variable geometry, intake, twin-scrolling, electric...etc...a lot of work has been done to make that turbine wheel spin up to full speed as soon as they can make it, which makes most turbo engined cars these days have a lot of torque at low revs, with a max torque range farther & wider than before. However, that doesn't means Turbo Lag has been totally eradicated, it still exist in many >1.5L engines with manual gearboxes. The worst offender for me is the Ford's 1L Ecoboost. Try accelerate from 80-110 km/h as quick as possible in top gear and you start to wonder do you have to go all the way back down to 2nd because you'll get nothing in 6th, 5th, 4th, even 3rd!

Small block 90度V8是很有代表性的美國文化，我們在 Lancia Thema那段片講過一點相類似的設計，但那是偏向歐洲的高轉作風。有機會詳細談一下這兩個不同派別的V8

非同步摩打即異步感應摩打，其轉子的磁場是透過定子磁場變化感應出來，家庭電器的摩打通常都是這種。

對，石油氣引擎跟電油引擎相近。

電子油門只能改變節氣門開啟的幅度和速度，要真正改變輸出性能，要調校燃油量和點火時間才行。

汽油柴油都是石油燃料，你是說石油氣嗎？石油氣的能量密度低（含碳量少），動力不能滿足高性能汽車。

@@sir167 Yes, that's kinda why LPG was once quite big in UK but then ended up being dropped due to lack of demand, not to mention you typically had to spend at least £2k to convert an old petrol banger to run on LPG as well as petrol as back up. my mate had done just that with his RX-8, yes the fuel is nearly 1/2 priced, but he ended up going to that filling station EVEN more often than before, lol!

主要同引擎結構，轉動慣性有關，轉動部件越輕，沖程越短越容易有高轉，2沖程主要是因為每圈點火，爆炸力比4沖的每兩圈點火大，轉數提升快，而4沖超過萬8轉有難度，難度其實吾系曲軸追吾到，系氣門彈簧追吾到，所以有d 會用氣壓氣門破轉數，2沖就因為中缸有進排氣孔，做成壓縮比吾可以太高，引致低扭非常差，算系因為當年為左追求馬力而出現既異類

香港市場小，名品牌汽油辛烷值都是最高級的98，應該不出現引擎性能過高辛烷值不足的情況（在美國很普遍），各品牌不同之處是添加劑，各廠有自家獨門秘方，功能都是以抗磨清潔減少積碳為主，同時各品牌都有平貴油之分，分別在於揮發性，汽油不是單一份子的化合物，是介乎戊烷到辛烷之門的一系列化合物，貴油是煉油過程中精煉提取揮發性較高的一部份。

That's to do with the additives each individual fuel companies put in their fuel, some might contain more cleaning agent, some might make them easier to burn completely, etc... as far as I know, all petrol sold in HK are 98 RON the difference is just on the additives and how much of that in them. In UK, all petrol station sells 95 RON (was E5 blend, 5% Bio-Ethanol, recently changed to E10, 10% Bio-Ethanol, the rest is petrol) as well as 97-99 RON depending on where you go to. Supermarket sells petrol as well as the usual players like Shell,Esso,BP,Texaco(Caltex),Gulf... The most important thing is RON number and knowing what your engine should run on. If you have a BMW M car, you'd run higher RON fuels than say a normal BMW. But then I have also seen people fueling up their formula race car with supermarket 95 RON fuel...up to you...Your owner's manual and near the fuel filler cap should always have a sticker that tells you what fuel you can put in your car.

全合成5W/30或5W/40，牌子按個人喜好。

@@sir167 謝謝 龍Sir

你的體驗正正說明了柴油引擎扭力好轉速範圍窄，石油氣引擎性能跟汽油引擎接近，扭力不大轉速較高。

1. 汽油引擎在NA年代，一般認為300cc到400cc，直徑約80mm最好，平衡了火焰傳播時間和活塞重量引至振動問題，近年的direct injection turbo主張轉速和燃燒過程慢一點，很多車廠主張500cc，但這不是絕對的，各師各法，不同車廠有各自的考量。至於柴油，由於容積、轉速的變化相差可達幾百倍，很難說一個最佳容積。 2.引擎的功能是燃燒產生熱能再轉為動能，摩打的工作是將需能轉化為動能，工作相對簡單，效率很高，即是說要改善的空間也不太大，摩打大小視乎該車的目標市場而決定，續航力如何主要受逆變器效率和駕駛風格景響。

@@sir167 先多謝龍sir解說 延續第二條問題，電動車嘅進步空間已經不大？ 如果用個細d嘅摩打，扭力馬力功率輸出同汽油引擎差唔多，加返個波廂，舊電可唔可以細d輕d又行遠d？

@@sir167 如果電動車加入波箱令相同速度需要嘅轉速降低，理論上應該可以加長續航力？

@@thomaswong0622 電動車加波箱主要功能是捕足最佳效率，理論上可以增加續航力，但再差很微，很多車廠覺得令機械更複雜得不嘗失，並不划算。

還會加速，但不會像剛起步那麼猛。

為了控制排放現時的柴油引擎用了很多新技術如EGR, DPF, SCR等等，這些零件定期需要保養清理的，如果行車時間太短，零件常常不在正常溫度下工作，會加快積碳，但即使在正常溫度下工作也需要定期保養，那是開柴油車的成本。

當然要拎去車房搞，雖然到最後可能只係sensor壞左。 但係始終唔係專業人士，錶板基本上唔會呃人，佢著得點都係有狀況發生，用網上旁門左道整熄盞燈，只代表唔知邊日成個系統死左，盡快俾專業人士搞比較好

揸車最基本嘅，好彩啲學車時師傅，朋友都會俾啲心得，例如最基本空波俾油先上波，雖然最基本，但同時係對車好，最標準

石油氣引擎工作原理和汽油引擎很相似。

何謂燃燒室的理想容積，考慮的包括直徑和行程，活塞重量，火焰能否在短時間內傳遍燃燒室等，在流行NA高轉的年代，400cc左右被認為是理想容積，現時流行的direct injection turbo，崇尚低轉扭力，由於轉慢一點，火焰夠時間跑遠一點，可以將燃燒室做大一點，有車廠認為500ccm 更理想。