УРЛАГ
ГОО САЙХАН БА ЭРҮҮЛ МЭНД
ГАРААР ХИЙСЭН
СОЁЛ БА ТҮҮХ
ҮЗВЭР НААДАМ
БАЙГАЛЬ ОРЧИН
ХООЛ БА УНДАА
УРВУУ ИНЖЕНЕРЧЛЭЛ
ШИНЖЛЭХ УХААН
СПОРТ
ТЕХНОЛОГИ
ӨМСДӨГ ХЭРЭГСЭЛ
The Two-Stroke Engine: The Piston Is the Valve
The four-stroke engine fires once every two turns and needs cams, springs and valves to breathe. Joseph Day's engine of 1891–95 fires every turn and has none of them: the piston itself opens and closes ports in the cylinder wall, and the sealed crankcase under the piston acts as a pump that pre-compresses the fresh charge.
Its own specification puts it simply: the piston *"serves as a slide-valve"*, doing away with *"eccentrics, cams, valve-rods"*. That makes it light, cheap and powerful for its size — the engine of chainsaws, mopeds and outboard motors.
This rung computes its port timing from the crank geometry and cuts the ports into a card cylinder on the slider-crank model to watch them open.
Дунд шат
About 3 hours
Зааварчилгаа
1
1
Read Day's patent
Read Day's patent
US 543,614, 'Gas Engine', Joseph Day, patented 30 July 1895. The aim is *"a gas-engine in which eccentrics, cams, valve-rods, and other positively-actuated"* parts are done away with, *"the piston itself"* serving *"as a slide-valve"*. The explosive mixture is drawn into the crankcase chamber by the up-stroke, compressed there by the down-stroke, and delivered into the upper part of the cylinder when the piston uncovers the port; the piston also uncovers the exhaust port. Day's drawing still shows a valve admitting the charge to the crankcase — look for it.
2
2
Port timing from the geometry
Port timing from the geometry
Jupyter дэвтэр ачаалж байна…
3
3
Cut ports and watch them open
Cut ports and watch them open
On the slider-crank model from the crank rung, wrap a card tube round the slider's path as a 'cylinder' and mark on it the piston crown's position at top dead centre. Cut an exhaust window starting 60 % of the stroke below that mark, and a transfer window starting 72 % down, on the opposite side.
Turn the crank slowly with the protractor underneath and note the angle at which the crown first uncovers each window, and when it covers it again. Compare with the notebook.
Энэ алхмын материал:
Картон хоолой1 ширхэгШаардлагатай багаж:
Транспортир
Шугам
Арилдаггүй маркер4
4
History and context
History and context
**US 543,614, 'Gas Engine', Joseph Day, patented 30 July 1895.** Day was an engineer in Bath, England, and had patented crankcase compression in Britain before this US patent; the two-stroke spread quickly to motorcycles and small boats.
**Honest limits.** The ports are open together, so some fresh charge escapes with the exhaust — wasteful and polluting in a carburetted engine. The crankcase carries the charge, so lubricating oil is usually mixed into the fuel and burned. The two-stroke survives where power for its weight matters more than economy.
Материал
1- 1 ширхэгТүр орлуулагч
Шаардлагатай багаж
3- Түр орлуулагч
- Түр орлуулагч
- Түр орлуулагч
Холбоотой загварууд
Эдгээр загварууд мэдлэг хуваалцдаг — арга техник, материал эсвэл зарчим
Otto Four-Stroke Engine
Martin зохиосон
Физик
46
0
0
0
0
0
The Crank and the Flywheel: Smoothing One Bang in Two Turns
Martin зохиосон
Механик
9
0
0
0
0
0
The Piston Ring: Sealed by the Gas It Holds Back
Martin зохиосон
Механик
7
0
0
0
0
0
The Carburettor: A Venturi, a Jet and a Float
Emma зохиосон
Механик
8
0
0
0
0
0
Roots Blower
Karen зохиосон
Механик
39
0
0
0
0
0
CC0 Нийтийн домэйн
Энэ загвар CC0 дор гаргагдсан. Та зөвшөөрөл авахгүйгээр хуулах, өөрчлөх, түгээх, ашиглах боломжтой.
Загвараар дамжуулан бүтээгдэхүүн худалдаж авч Бүтээгчийг дэмжээрэй Бүтээгчийн шимтгэл Борлуулагчаар тогтоосон, эсвэл энэ загварын шинэ хувилбар үүсгэж орлогоо хуваахын тулд өөрийн загварт холбоос болгон оруулна уу.