How is the crank and camshaft gear ratio calculated?
- Thread starter hidrojen
- Start date
Help Support Home Model Engine Machinist Forum:
Says "Turkish detected" on the translator, as follows:
"Hello friends, how is the ratio of crankshaft gear to camshaft gear calculated? Do Top dead center and Bottom dead center have anything to do with this?"
2:1 for a typical four stroke.
Crankshaft turns twice as fast as the camshaft.
.
"Hello friends, how is the ratio of crankshaft gear to camshaft gear calculated? Do Top dead center and Bottom dead center have anything to do with this?"
2:1 for a typical four stroke.
Crankshaft turns twice as fast as the camshaft.
.
When calculating the gear as 2:1, do we calculate the up and down distance?
And the crank gear should be 20 and the eccentric gear should be 10?
The cam (eccentric) gear will have two times as many teeth as the crankshaft gear. Like Green Twin said, the crankshaft turns twice as fast as the camshaft. In your example, the crank gear would have 10 teeth and the eccentric gear 20 teeth.
Top and bottom center distance are not part of the calculation.
Regards,
Chuck
Top and bottom center distance are not part of the calculation.
Regards,
Chuck
But if you use that intermediate gear for ignition or fuel pumping purposes, it is important and needs to be kept in a 1-2 ratio with the crankshaft gear.
There always has to be one.............
Flights to the moon require some mod as well...this has nothing to do with fuel pumps or ignition timing running off intermediate gears.
Never seen intermediate gears use for that purpose anyhow.
Grow up.
You don't see, you haven't seen, you've never done...doesn't mean it never existed. I did that
Jens Eirik Skogstad
Active Member
- Joined
- May 27, 2023
- Messages
- 25
- Reaction score
- 28
Lawn mover engine and some motorcycle engine has contact breaker affected by crank shaft instead camshaft. Duration of cam timing and point of ignition timing and fuel pump ignition are determined by cam angle, not gears. To example the crank shaft timing 120 degree, then the cam need to be 60 degree from open to closed in the valve. Fuel pump timing is determined of the point of where it begins to pump the fuel before TDC and height of cam is max amount of fuel, but the amount of fuel is determined by regulator in the fuel pump in the diesel engine to regulate from idling to max revolution then the max of height in the cam to inject the fuel is not always used to not rev up the engine to preventing overloading the engine.
And the new turkish member hidrojen who need to read here: Çim biçme makinesi motoru ve bazı motosiklet motorlarında, eksantrik mili yerine krank milinden etkilenen kontak kesici bulunur. Kam zamanlamasının süresi ve ateşleme noktası zamanlaması ve yakıt pompasının ateşlenmesi, dişlilere göre değil kam açısına göre belirlenir. Örneğin krank mili zamanlaması 120 derece ise, valfte kamın açıktan kapalıya 60 derece olması gerekir. Yakıt pompası zamanlaması, TDC'den önce yakıtı pompalamaya başladığı noktaya ve kam yüksekliğinin maksimum yakıt miktarına göre belirlenir, ancak yakıt miktarı, dizel motorda yakıt pompasında bulunan regülatör tarafından rölantiden rölantiye kadar ayarlanır. maksimum devir ve ardından yakıtı enjekte etmek için kamdaki maksimum yükseklik, motorun aşırı yüklenmesini önlemek için her zaman motor devrini yükseltmemek için kullanılmaz.
hidrojen
Dişli oranı 1:2, düz metin olarak şu anlama gelir: Krank mili 1'e karşı eksantrik mili 2, örneğin krank milinde 20 dişli bir dişli vardır ve eksantrik milinde 40 dişli bir dişli vardır. Yani kam tahrikinin diş sayısını iki katına çıkarın.Bilindiği gibi 1:2, 1:3, 1;4 vb. tam dişli oranlarında sürücüdeki dişlerin aşınmasıyla ilgili iyi bilinen bir sorun vardır, yapabileceğiniz en iyi şey 34 veya 34 dişli bir ara sürücü koymaktır. 36 dişli veya bir dişi çok fazla veya bir tanesi çok az olan bir triger kayışı, böylece triger kayışındaki dişlerde daha az aşınma olur ve her ikisi de krank mili ve eksantrik mili üzerinde tahrik sağlar.
Şanzımanda ve arka aksta hiçbir zaman tam sayı oranlarını bulamazsınız, örneğin 1 vites 1:3,4- 2 vites 1:85, - 3 vites 1:28- 4 vites 1:1 (motordan arka aksa doğrudan) ) - 5 vites 1:0,76 ve geri vites 1:3.94 ve arka aks 1:3.92
Model motorlar araçlardaki büyük motorlar kadar saat çalışmadığından endişelenmenize gerek yoktur. Daha sonra, ara tahrik olmadan yalnızca 2 tahrikli bir motoru çalıştırıyorsanız veya gücü krank milinden eksantrik miline aktarmak için triger kayışı kullanmadıysanız da aynı şekilde çalışır. Triger kayışına sahip çok fazla model motor yoktur.
Eksantrik milindeki açılma açısı diyagramı zamanlamada krank milinin yarısı kadardır.
In english to other readers:
Gear ratio 1:2 means this in plain text: Crankshaft 1 vs camshaft 2, for example the crankshaft has a 20-tooth gear and the camshaft has a 40-tooth gear. So double the number of teeth for the cam drive.
As is known in full gear ratios such as 1:2, 1:3, 1;4 etc have a well-known problem with wear of teeth in the drive, the best thing you can do is put an intermediate drive that has 34 or 36 teeth or a timing belt that has one tooth too many or one too few so that there is less wear on the teeth on the timing belt and both drives on the crankshaft and camshaft.
In the gearbox and rear axle you will never find ratios in whole numbers, for example 1 gear 1:3,4- 2 gear 1:85, - 3 gear 1:28- 4 gear 1:1 (direct from engine to rear axle) - 5 gear 1 :0,76 and reverse gear 1:3.94 and the rear axle 1:3.92
In model engines, there is no reason to worry as they do not run as many hours as the large engines in vehicles. Then it works just as well if you run an engine with only 2 drives without an intermediate drive or if you have not used a timing belt to transfer power from the crankshaft to the camshaft. There are not many model engines that have a timing belt.
Opening angle diagram in camshaft is half of crankshaft in timing.
They are all in one system and they are related to each other !!!!!!!
Jens Eirik Skogstad
Active Member
- Joined
- May 27, 2023
- Messages
- 25
- Reaction score
- 28
Nobe,.. the gear ratio does not affect timing, only the ratio in revolutions. Timing is affected by camshaft in angle + regulator to example mechanical centrifugal regulator and vacuum regulator on distributor in petrol engine for ignition timing. The diesel pump has its own regulator for timing and the amount of fuel that is injected into the engine. Duration of valve timing affected by cam in angle on cam shaft.
I stop arguing !
