Essential reading: SPINČIĆ, A., PRITCHARD, B, An English Textbook For Marine Engineers 2, Pomorski fakultet, Rijeka LUZER, J., SPINČIĆ, A., Gramatička vježbenica engleskog jezika za pomorce, Pomorski fakultet, Rijeka Tomislav Skračić, MA Undergraduate English Course for MARINE ENGINEERS 4th Semester

LESSON 6 CYLINDER HEAD AND VALVES

Lesson 6 Cylinder Head and Valves KEY WORDS cylinder head- glava cilindra cylinder cover- glava / poklopac cilindra outer cylinder cover- vanjska glava cilindra (velika)[1][1] cylinder cover-insert- unutarnja glava (mala) valve- ventil stud (n.)- usadni vijak, "pržunjer" firing loads- opterećenja izgaranja / ekspanzije metallic joint- metalni spoj / brtva shim (n.)- podloška, "bajlaga" borehole (n.)- izvrtani / izbušeni otvor [1][1] Na starijim Sulzerima, danas većina motora ima 1 glavu.

Lesson 6 Cylinder Head and Valves VALVES starting v.- uputni ventil, v. uputnog zraka air starter / starting air v.- ventil uputnog zraka injector / fuel injection v.- v. goriva, ubrizgač safety v. = relief v.- sigurnosni, odušni ventil, "šigureca" indicator v.- indikatorski v. / pipac exhaust v.- ispušni v. air inlet v. = intake v.- usisni ventil

Lesson 6 Cylinder Head and Valves tension (n.)- napon, napetost tension stud- pritezni vijak clamp down- pritegnuti, stisnuti cylinder cover stud- vijak glave cilindra, "pržunjer" with the aid of- uz pomoć, pomoću sealing ring- brtveni prsten control bore- kontrolni kanal / otvor in turn- naizmjenice, redom sequence (n.)- redoslijed, slijed bring down- sjesti, prilegnuti, spustiti (se)

Lesson 6 Cylinder Head and Valves tightening (n.)- stezanje crosswise tightening- unakrsno stezanje torque wrench- moment-ključ stretch of a stud- rastezanje / vlak vijka nozzle (n.)- mlaznica, sapnica tangentially- tangencionalno, pod kutem inspection of the cooling water spaces- pregled, nadzor circumference (n.)- obujam, opseg, periferija via - putem (e.g. Split–Šibenik via Boraja / news via satellite) conducting pipe- provodna cijev insert (n.)- umetak outlet pipe- ispusna cijev

1. DEFINITION  Cylinder head is a casting that covers the top of a cylinder 2. FUNCTION  to close tightly / seal off the top of cylinders.  to form the combustion chamber, together with the piston crown or, in some cases, with the liner itself.  to carry the injector and the valves

3. VALVES All internal combustion engines (2- or 4-stroke) have:  an air starting valve which admits compressed air into the cylinder for starting purposes;  a safety or relief valve is a spring loaded valve set to a safe limit which releases excessive pressure;  an indicator cock which is used as a point of the indicator mechanism attachment.  4-stroke engines have inlet and exhaust valves.

Spring loaded non-return safety valve

Exercise 1 – Name the parts of the cylinder head:

4. STRESSES  High pressure and temperature due to combustion 5. REQUIREMENTS  Strong, sturdy construction / manufacture  Carefully cooled 6. COOLING  Is executed by F.W. circulation, as excessive temperature may give rise to damage by cracking 7. MATERIAL  Cast or forged steel  Special cast iron

Cooling of the cylinder head

Cooling of the cylinder head

8. DESIGN – not simple. It has valve bores and passages. o RND-MOne piece steel block with cooling bores. o B & W (K-GF Type)Two parts: outer cover and inner insert. The head is a solid steel plate with radial cooling water bores. The insert contains a bore for the exhaust valve cage and mountings for fuel valves, a safety valve and an indicator valve. o B & W (K-GF Type)One piece of forged steel with cooling water drillings. o Sulzer Z40The double bottom water cooled cylinder head made of special cast iron. It has two inlet and two exhaust valves as well as a centrally arranged fuel valve.

9. HEAD SECURING  By studs made of alloyed steel with close-pitch thread.  The heads are held in place / held against the cylinder liner top collar by: studs screwed into the cylinder block studs attached to the cylinder frame studs tightened by hydraulic tools.

Studs are made of special steel alloyed with 0.8% of carbon

1.Name the valves that may be accommodated in the cylinder head. 2.Are the cylinder heads fitted with inlet and exhaust valves in all marine engines? 3.What is the purpose of the relief valve? 4.What is the function of the studs? 5.Why should the studs be tightened evenly? 6.How are the studs tightened? 7.What is the purpose of the control bore? 8.How can the injector be arranged? 9.What else does the cylinder head accommodate? Exercise 2 – Answer the following questions: