Automobile L4-U2-S1-Reconditioning of Valve Mechanism

 

 

Session – 1 (Reconditioning of valve mechanism)

Q.1.  What is the function of Valve? Tell about the types of its mechanism. (वाल्व का क्या कार्य है?)

Ans.  Valve is a device used to control the timing and quantity of gas or vapour flow into an engine. (वाल्व एक ऐसी डिवाइस है जिसके द्वारा इंजन में गैस और वाष्प के बहाव की टाइमिंग और मात्रा को नियंत्रित किया जाता है।)

 

Q.2. What is valve mechanism? What are its types? (वाल्व मैकेनिज़्म क्या है ? इसके क्या प्रकार हैं?)

Ans. 

               Value mechanism fuEu nks izdkj dh gksrh gS %&

a.            Overhead Valve Mechanishm (OHV)

b.            Overhead Cam Mechanism (OHC)

              

Overhead Valve Mechanism:- bl mechanism esa inlet valve, exhaust valve, spring lock, valve seat, valve spring, push rod, rocker arm, rocker shaft vkfn vkrs gSA bl case esa camshaft crankcase esa fix gksrh gSA  

Overhead Cam Mechanism:- bl eSdsfuTe esa Hkh buysV okYo exhaust valve, valve guide, valve spring lock, valve seat, rocker arm vkSj rocker shaft vkfn vkrs gSA blesa dSe'kkQV gSM ds Åij fix dh gksrh gSA ;g okYo eSdsfjTe ds dk;Z ds fy, de batu dh ikoj dh [kir djrh gSA  

 

Q2.         Valve leakage ds D;k dkj.k (causes ) gks ldrs gSA

Ans.       ;fn Valve ls combustion gases yhd gks jgh gSa rks blds fuEu dkj.k gks ldrs gS%&

o   vR;f/kd Fuel dh [kir (consumption)

o   fid&vi u gksukA

o   batu dk yksM+ u ys ikukA

o   LVkfVZax gkMZ gks tkukA

o   Valve dk stick djukA

o   batu dk Overheat  gksukA

Q3.        Valve mechanism dh leakage tk¡pus ds fy, dkSu lk test fd;k tkrk gSA

Ans.       blds fy, batu dk compression test fd;k tkrk gSA

 

Q4.         Vlave dh reconditioning D;ksa dh tkrh gSA blesa dkSu&2 lh processes vkrh gS \

Ans.       Gases dh leakage ds dkj.k valve dh reconditioning dh t:jr iM+rh gSA Valve dh reconditioning esa ubZ valve seat dk insert djuk] Valve seat grind djuk] valve dk reface djuk] valve dh lapping djuk] valve dh tappet clearn set djuk vkfn vkrs gSA bu lHkh processes ds lkFk lkFk batu ds smooth performance vkSj power dh vf/kdre output ds fy, valve dh service  gSA

 

Q5.         Valve Reconditioning dh fof/k crk,aA

Ans.      

(i)            lcls igys batu ls cylinder head dks gVk,aA

(ii)           ,d ckj cylinder head vyx gks tk, rks head ls carbon dks gVk nsA mlds ckn flySaMj CykWd vkSj fiLVu ls Hkh dkcZu gVk nsaA

(iii)          fiLVu dk top clear djrs le; ;g /;ku j[ksa fd gouging vkSj scratching u gkus ik, D;ksafd rough spots dkcZu dks readily collect djrs gS ftlls dk;Z&fof/k ds nkSjku pre-ignition vkSj detonation gks ldrh gSA

(iv)          iSVªksy esa FkksM+h ek=k esa feV~Vh dk rsy feyk,a vkSj dropper dh lgk;rk ls valve face ij liquid dks fxjk,aA

(v)           Valve spring compressor dh lgk;rk ls valve dks gVk,a] valve dh leakage dks observe djsaA

(vi)          uhyk jax leakage area dks n'kkZrk gSA

(vii)         blds ckn valve dks wire brush ls lkQ djsA

(viii)        Valve ds vius LFkku u cny tkus esa lko/kkuh cjrsaA

(ix)          izR;sd valve nqckjk mlh valve port esa yxuk pkfg, tgka ls mls fudkyk x;k FkkA

(x)           ;fn valve vkil esa LFkku ls cnys x, rks blls valve vkSj stem dh f?klkoV c<+ tk,xhA

(xi)          blh confusion ls cpus ds fy, vki valve dh cylinder wise igpku cukus ds fy, ,d system devlop dj ldrs gksA

 

Q6.         Valve face dks reface dSls djsaxsA

Ans.       Vlave face dks reface valve grinding ;k refacing machine }kjk fd;k tkrk gSA

(i)            Valve dh radial run out dks 2⁰ ,oa valve dk margin 2mm ls de j[ksa ;fn ,slk ugha gS rks valve dks  replace djuk vko';d gks tkrk gSA

(ii)           Valve dks refacing machine ij j[ksaA

(iii)          Machine dks 35 ls 45⁰ ds angle ij lSV djsaA

(vi)          Machine dks start djsaA

(v)           Collant supply dks open djsa vkSj /khjs&/khjs ls refacing operation dks start djsaA

 

Q7.         Vlave seat cutting ;k grinding operation ds ckjs esa crk,aA

Ans.

(i)            Valve seat ds angle dh eki djsaA

(ii)           Valve seat dk margin pSd djsa ;fn ;g 2mm ls de gS rks valve seat dks replace djsaA ;fn ;g 2 mm ls vf/kd gks rks ;g lq>ko fn;k tkrk gS fd valve seat dk dk;Z fd;k tk,A

(iii)          Appropriate size dk grinder/cutter select djsaA

(vi)          Holder vkSj pilot dks grinding stone ds lkFk fix djsaA

(v)           vc valve seat dks machine ds lkFk ;k manually grind djs vkSj valve seat dks mfpr angle ikus ds fy, grind djsaA

 

               Valve Lapping Operation:-

(i)            mfpr size dh valve lapping stick dks select djsaA

(ii)           bldh rubber side dks valve face ij j[ksaA

(iii)          Abrasive ;k emery coarse paste dks valve face ij yxk,aA

(iv)          vc lapping stick dks clockwise ;k anti-clockwise fn'kk esa ?kqek,a ;g valve dks valce seat dks lap dj nsxkA