Transcript Document
Tomislav Skračić, MA
Undergraduate English
Course for
MARINE ENGINEERS
4th Semester
Essential reading:
SPINČIĆ, A., PRITCHARD, B., An English Textbook For
Marine Engineers 2., Pomorski fakultet, Rijeka 2009.
LUZER, J., SPINČIĆ, A., Gramatička vježbenica engleskog
jezika za pomorce, Pomorski fakultet, Rijeka 2003.
Lesson 8
VALVE OPERATING GEAR
Lesson 8
Valve Operating Gear
KEY WORDS
valve operating gear
times in the cycle
push rod
train of gears
chain drive
keyed on
bolted together
follower (n.)
hinged follower
sliding follower
- ventilno polužje za pokretanje ventila
- momenti kružnog procesa / ciklusa
- spojna motka, podizač
- niz zupčanika
- lančani prijenos
- učvršćen / osiguran klinom
- spojen vijcima (danas se koriste
SKF couplings - spojke na principu smicanja)
- vodilica, podizač (usp. 'roller guide')
- zglobni podizač brijega, "britvela"
- klizni podizač
Lesson 8
Valve Operating Gear
KEY WORDS
lever form folower
tappet form follower
side thrust
fulcrum pin
pivot (n.)
bronze bushing
set screw
lifting rod
idle gear [aidl]
- podizač u obliku poluge
- podizač u obliku cilindra
- bočna sila / potisak
- uporište poluge
- os, hvatište, utorište
- brončana rupa za osovinicu, bukola
- pritezni vijak, podešavajući / regulacijski vijak
za zračnost i sl.
- podizna motka
- međuzupčanik
Lesson 8
Valve Operating Gear
1. DEFINITION
A mechanism for actuating & controlling the inlet and exhaust
valves. It may also open and close air starting valves and fuel
pumps.
2. OPERATION OF VALVES
Mechanical (valve operating gear)
Exhaust valve operating gear
1. DEFINITION
A mechanism for actuating & controlling the inlet and exhaust
valves. It may also open and close starting air valves and fuel pumps.
2. OPERATION OF VALVES
Mechanical (valve operating gear)
Hydraulic. There are neither pushrods nor rocker arms but a
piston pump. The oil pressure is led by means of a high
pressure pipe to a working cylinder and hydraulic piston placed
on top of the exhaust valve cage.
Hydraulically operated exhaust valve (Sulzer)
3. CAMSHAFT
3.1 CONSTRUCTION
Integral camshaft is made in a single piece of forged steel;
Separate cams of forged steel or cast iron are:
keyed on the shaft;
hyraulicaly shrunk on or press fitted;
fitted to the shaft by SKF oil injection pressure method.
3.2 CAM DESIGN
3.3 CAMSHAFT ROTATION
4-stroke = ½ speed of the crankshaft
2-stroke = same speed as the crankshaft
3.4 CAMSHAFT DRIVE
Train of gears
Chain drive
3.5 REVERSING
The camshaft slides axially (in 4-stroke engines) thus bringing a
different set of cams for reverse direction.