{"id":6825,"date":"2014-03-22T17:47:36","date_gmt":"2014-03-22T15:47:36","guid":{"rendered":"http:\/\/mixmotor.eu\/?p=6825"},"modified":"2014-03-22T18:08:20","modified_gmt":"2014-03-22T16:08:20","slug":"vyznam-geometrie-v-rozvodovom-mechanizme-cast-2","status":"publish","type":"post","link":"https:\/\/mixmotor.eu\/en\/6825\/vyznam-geometrie-v-rozvodovom-mechanizme-cast-2","title":{"rendered":"V\u00fdznam geometrie v rozvodovom mechanizme – \u010das\u0165 2."},"content":{"rendered":"

V prvej \u010dasti<\/a>\u00a0som spomenul z\u00e1kladn\u00e9 \u010dasti rozvodov\u00e9ho mechanizmu a krit\u00e9ria pri v\u00fdbere spr\u00e1vneho vahadla. V tejto \u010dasti sa budem venova\u0165 ventilov\u00fdm pru\u017ein\u00e1m, tiahl\u00e1m a modern\u00fdm pom\u00f4ckam pri nastavovan\u00ed rozvodov\u00e9ho mechanizmu.<\/p>\n

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Ventilov\u00e9 pru\u017einy<\/strong><\/p>\n

\"\"<\/a>

v\u013eavo pru\u017eina typu beehive (tvar podobn\u00fd v\u010del\u00edmu \u00fa\u013eu)
a vpravo klasick\u00e1 valcov\u00e1 pru\u017eina<\/p><\/div>\n

Pre pr\u00edle\u017eitostn\u00fdch pretek\u00e1rov a pouli\u010dn\u00fdch \u00fapravcov je jednoduch\u00e9 siahnu\u0165 po s\u00fa\u010diastkach overen\u00fdch v pretek\u00e1rskych motoroch, ale tieto vylep\u0161enia sa v\u00fdrazne prejavia na celkovom \u00fa\u010dte za \u00fapravy. Treba si preto uvedomi\u0165 a zv\u00e1\u017ei\u0165, \u010do v skuto\u010dnosti vyu\u017ei\u0165 vo svojom agreg\u00e1te. “Ak ot\u00e1\u010dky motora dosahuj\u00fa hodnotu 9000 a\u017e 10000 ot\/min pou\u017eitie kvalitn\u00e9ho a pevn\u00e9ho rozvodu je nevyhnutn\u00e9,” varuje Hooper. Do be\u017en\u00fdch motorov to nie je v\u0161etko potrebn\u00e9. Dobr\u00e1 geometria rozvodu je st\u00e1le ve\u013ek\u00e9 plus. Ma\u0165 tie naj\u0161pi\u010dkovej\u0161ie s\u00fa\u010diastky za vysok\u00e9 ceny a pritom nema\u0165 obavy, \u017ee sa nie\u010do m\u00f4\u017ee zlomi\u0165 je pekn\u00e9, ale je potrebn\u00e9 to\u013eko investova\u0165?? Toto plat\u00ed ako aj pre ventilov\u00e9 pru\u017einy tak ja pre ostatn\u00e9 komponenty rozvodu. Ak motor nepresahuje cez 7000 ot\/min, tak nie je d\u00f4vod \u00a0pou\u017e\u00edva\u0165 dvojit\u00e9 pru\u017eenie a ostatn\u00e9 veci okolo toho. Ve\u013ea \u013eud\u00ed rob\u00ed ve\u013ek\u00fa chybu t\u00fdm, \u017ee pou\u017eij\u00fa star\u00e9 osved\u010den\u00e9 dvojit\u00e9 pru\u017eenie a pohyb ventilu \u00a0“prepru\u017eia”. Beehive (\u00fa\u013eov\u00e9) pru\u017einy dnes zvl\u00e1daj\u00fa 7000 a\u017e 7500 ot\/min, \u010do plne posta\u010duje pre s\u00e9riov\u00e9 motory.<\/p>\n

\"DSC_0044\"<\/a>

Hore klasick\u00e9 tiahlo a dolu nastavite\u013en\u00e9 tiahlo pomocou, ktor\u00e9ho sa zis\u0165uje spr\u00e1vna d\u013a\u017eka.<\/p><\/div>\n

Samozrejme pretek\u00e1ri dosiahnu bod, kde \u0161tandardn\u00e9 strat\u00e9gie neposkytuj\u00fa viac v\u00fdsledky a v\u00fdpo\u010det geometrie rozvodu naber\u00e1 nov\u00e9 dimenzie. P\u00e1r vec\u00ed je, na ktor\u00e9 sa treba e\u0161te pozrie\u0165 pri vahadl\u00e1ch. Pomerom str\u00e1n vahadla dostaneme hodnotu zdvihu teda vieme ako vysoko sa ventil zodvihne. D\u00f4le\u017eit\u00fd faktor je d\u013a\u017eka \u010dapu vahadla, preto\u017ee\u00a0pri vysok\u00fdch ot\u00e1\u010dkach nadob\u00fada \u010dap tvar obl\u00faku. \u010c\u00edm je \u010dap dlh\u0161\u00ed t\u00fdm je jeho obl\u00fak v\u00e4\u010d\u0161\u00ed a \u00a0ak m\u00e1me kr\u00e1tky \u010dap nedoch\u00e1dza k jeho oh\u00fdbaniu a m\u00e1 ve\u013emi mal\u00fd obl\u00fak. “Ke\u010f sme sa dostali k pretek\u00e1rskym motorom, tak sme tam dostali v\u00e4\u010d\u0161ie zdvihy. Chceli sme za\u010da\u0165 s dlh\u0161\u00edmi \u010dapmi”, \u010falej dop\u013a\u0148a Hooper. “Ale s ve\u013ek\u00fdm mno\u017estvom valcov sme boli v\u00e1\u017ene obmedzen\u00fd, preto\u017ee zdv\u00edhadla zasahovali do sacieho potrubia, \u010do nemohlo fungova\u0165 dobre.” Jedn\u00fdm z mo\u017en\u00fdch rie\u0161en\u00ed je pou\u017ei\u0165 usporiadanie typu Jesel, \u010do znamen\u00e1, \u017ee niektor\u00e9 vahadla s\u00fa nato\u010den\u00e9 o in\u00fd uhol oproti ostatn\u00fdm. V\u010faka tomu m\u00f4\u017eeme pou\u017ei\u0165 dlh\u0161ie \u010dapy na vahadl\u00e1ch a \u00a0pritom m\u00e1me dostatok miesta pre nas\u00e1vacie potrubie.<\/p>\n

\"Sportsman_Head2<\/a>

Usporiadanie vahadiel Jesel<\/p><\/div>\n

V\u00fdvoj<\/b><\/p>\n

Hoci z\u00e1klady geometrie rozvodov\u00e9ho mechanizmu sa za posledn\u00e9 roky nezmenili, zmenami pre\u0161lo n\u00e1radie a materi\u00e1ly pre prec\u00edzne ladenie rozvodov. Napr\u00edklad s pr\u00edchodom 3D digitaliz\u00e1cie a 3D tla\u010diarn\u00ed umo\u017enilo stavite\u013eom motorov r\u00fdchlo\u00a0vytvori\u0165 \u00a0koncepty s\u00fa\u010diastok a n\u00e1sledne ich otestova\u0165. O tom mohli predch\u00e1dzaj\u00face gener\u00e1cie iba sn\u00edva\u0165. S 3D tla\u010diar\u0148ou za kr\u00e1tku dobu vytvoren\u00fd plastov\u00fd podstavec pod vahadlo m\u00f4\u017eeme namontova\u0165 a vysk\u00fa\u0161a\u0165, \u010di je vhodn\u00fd. V minulosti zabralo ve\u013ea \u010dasu experimentovanie a presuny s komponentmi tohto druhu\u00a0medzi mont\u00e1\u017enou a v\u00fdrobnou diel\u0148ou, \u010do mohlo predstavova\u0165 miesta vzdialen\u00e9 od seba nieko\u013eko kilometrov. Geometria sa teda nezmenila ale teraj\u0161ie technol\u00f3gie pon\u00fakaj\u00fa vyrobi\u0165 v\u0161etko, \u010do chceme a namontova\u0165 to okam\u017eite do hlavy valcov, kde zist\u00edme parametre ostatn\u00fdch s\u00fa\u010diastok. Pr\u00edchodom nov\u00fdch v\u00fdrobn\u00fdch technol\u00f3gii materi\u00e1lov sa zmenili v\u00fdpo\u010dty pre rozvody a poskytli z\u00e1klad pre revol\u00faciu vo v\u00fdrobe ventilov\u00fdch pru\u017e\u00edn. V kon\u0161trukcii pru\u017einy zohr\u00e1va materi\u00e1l najd\u00f4le\u017eitej\u0161iu \u00falohu. Pred pribli\u017ene 15 rokmi proste neboli dostato\u010dne kvalitn\u00e9 materi\u00e1ly pre pru\u017einy, ale s pr\u00edchodom iniciat\u00edvy od firmy PSI (Performance Springs Inc.) do\u0161lo k zmen\u00e1m v ch\u00e1pan\u00ed kmitania a vibr\u00e1ci\u00ed pru\u017e\u00edn. Zistili, \u017ee za l\u00e1man\u00edm pru\u017e\u00edn st\u00e1li ne\u010distoty v dr\u00f4te.<\/p>\n\n\n\n\n
\"emc-rockers\"<\/a><\/td>\n\"emc-rockers-4\"<\/a><\/td>\n<\/tr>\n
CAD software ve\u013emi pom\u00e1ha pri navrhovan\u00ed \u010dast\u00ed rozvodov\u00e9ho mechanizmu<\/em><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

T\u00e1to spolo\u010dnos\u0165 patrila k popredn\u00fdm v USA, ktor\u00e9 rie\u0161ili tieto probl\u00e9my. So zlep\u0161en\u00edm kvality v\u00fdroby pru\u017e\u00edn v USA a Japonsku a pr\u00edchodom “beehive” (\u00fa\u013eov\u00e9) pru\u017e\u00edn sa star\u00e9 met\u00f3dy dimenzovania odsunuli bokom. Roky predt\u00fdm sa pretek\u00e1rsky in\u017einieri sna\u017eili pred\u00eds\u0165 prasknutiam pru\u017e\u00edn t\u00fdm, \u017ee pou\u017e\u00edvali v\u00e4\u010d\u0161ie pru\u017einy alebo dvojit\u00e9 pru\u017einy. Hlavn\u00fdm probl\u00e9mom t\u00fdchto rie\u0161en\u00ed bolo, \u017ee vy\u017eadovali ve\u013ek\u00e9 mno\u017estvo energie pre udr\u017eanie mechanizmu v pohybe. S lep\u0161\u00edmi, silnej\u0161\u00edmi materi\u00e1lmi pru\u017e\u00edn, m\u00f4\u017eu kon\u0161trukt\u00e9ri pou\u017ei\u0165 men\u0161ie, rozumnej\u0161ie priemery a menej z\u00e1vitov pri zachovan\u00ed rovnak\u00fdch vlastnost\u00ed. Z\u00edskame t\u00fdm zna\u010dn\u00fa \u00fasporu hmotnosti. Ned\u00e1vne zv\u00fd\u0161enie kvality v\u00fdroby materi\u00e1lov znamen\u00e1 n\u00e1vrat star\u00fdch materi\u00e1lov. Tit\u00e1n bol pr\u00edli\u0161 drah\u00fd na pou\u017eitie v motoroch, ale nebolo in\u00e9 v\u00fdchodisko. Teraz v\u0161ak oce\u013e za\u017e\u00edva ve\u013ek\u00fd “comeback”. N\u00e1strojov\u00e9 ocele sa op\u00e4\u0165 pou\u017e\u00edvaj\u00fa v pretek\u00e1rskych motoroch, preto\u017ee m\u00f4\u017eu by\u0165 ten\u0161ie ako predt\u00fdm a ich pevnos\u0165 a hmotnos\u0165 dok\u00e1\u017ee konkurova\u0165 tit\u00e1nov\u00fdm zliatin\u00e1m.<\/p>\n

\"\"<\/a>

Spr\u00e1vna geometria rozvodu v z\u00e1vodnom motore zni\u017euje kmitania a vibr\u00e1cie a m\u00f4\u017ee umo\u017eni\u0165 stavite\u013eovi zn\u00ed\u017ei\u0165 tlaky na pru\u017einy.<\/p><\/div>\n

H\u013eadanie \u013eah\u0161\u00edch \u010dastiach rozvodu st\u00e1le prin\u00e1\u0161a po\u017eadovan\u00e9 v\u00fdsledky, ale v\u0161etko m\u00e1 svoj limit. Tiahla id\u00fa smerom opa\u010dn\u00fdm, preto\u017ee pretek\u00e1rske t\u00fdmi sa pou\u010dili z ch\u00fdb, na ktor\u00e9 pri\u0161li v priebehu rokov. Vo vysok\u00fdch ot\u00e1\u010dkach doch\u00e1dza k preh\u00fdbaniu a na\u0165ahovaniu tiahla. Po demont\u00e1\u017ei s\u00fa tiahla neporu\u0161en\u00e9 a v\u0161etko vyzer\u00e1 v poriadku. Deform\u00e1cie tiahel pod za\u0165a\u017een\u00edm sp\u00f4sobuje zmeny v \u010dasovan\u00ed ventilov a ventil nekop\u00edruje tvar profilu va\u010dky. Po\u017e\u00edvaj\u00fa sa teda v\u00e4\u010d\u0161ie a silnej\u0161ie tiahl\u00e1 na \u00fakor hmotnosti, pri\u010dom zabezpe\u010dia stabilitu aj pri vysok\u00fdch ot\u00e1\u010dkach.\u00a0Napriek neust\u00e1lemu pokroku sa ob\u010das st\u00e1va, \u017ee najlep\u0161\u00edm rie\u0161en\u00edm s\u00fa star\u00e9 rie\u0161enia. Podobn\u00e9 ve\u013ek\u00e9 tiahl\u00e1 pou\u017e\u00edval Ford v 60. rokoch v motoroch radu FE a dnes pou\u017e\u00edvame nie\u010do podobn\u00e9.<\/p>\n

Na z\u00e1ver len to\u013eko, \u017ee o geometrii rozvodu je mo\u017en\u00e9 p\u00edsa\u0165 desiatky kn\u00edh a teda ve\u013ek\u00e9 mno\u017estvo inform\u00e1cii tu nie je spomenut\u00e9. Berte teda tento \u010dl\u00e1nok len ak\u00fdmsi pr\u00edkladom ako sa rie\u0161i dan\u00e1 problematika v praxi a \u010do v\u0161etko to obn\u00e1\u0161a.<\/p>\n

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Autor: Maro\u0161 Uhrin \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Zdroj: enginelabs.com \u00a0 Foto: enginelabs.com, bastra.com, hotrod.com<\/p>\n

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V prvej \u010dasti\u00a0som spomenul z\u00e1kladn\u00e9 \u010dasti rozvodov\u00e9ho mechanizmu a krit\u00e9ria pri v\u00fdbere spr\u00e1vneho vahadla. V tejto \u010dasti sa budem venova\u0165 ventilov\u00fdm pru\u017ein\u00e1m, tiahl\u00e1m a modern\u00fdm pom\u00f4ckam pri nastavovan\u00ed rozvodov\u00e9ho mechanizmu.       Ventilov\u00e9 pru\u017einy Pre pr\u00edle\u017eitostn\u00fdch pretek\u00e1rov a pouli\u010dn\u00fdch \u00fapravcov je jednoduch\u00e9 siahnu\u0165 po s\u00fa\u010diastkach overen\u00fdch v pretek\u00e1rskych motoroch, ale tieto vylep\u0161enia sa v\u00fdrazne […]<\/p>\n","protected":false},"author":3,"featured_media":6833,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[4,1,3],"tags":[621,638,620,636,637,501],"class_list":["post-6825","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-dokumentarne","category-nezaradene","category-zaujimave","tag-geometria","tag-nastavenie","tag-rozvod","tag-tiahla","tag-vahadla","tag-ventilove-pruziny"],"translation":{"provider":"WPGlobus","version":"3.0.0","language":"en","enabled_languages":["sk","en","de"],"languages":{"sk":{"title":true,"content":true,"excerpt":false},"en":{"title":false,"content":false,"excerpt":false},"de":{"title":false,"content":false,"excerpt":false}}},"_links":{"self":[{"href":"https:\/\/mixmotor.eu\/en\/wp-json\/wp\/v2\/posts\/6825","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mixmotor.eu\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mixmotor.eu\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mixmotor.eu\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/mixmotor.eu\/en\/wp-json\/wp\/v2\/comments?post=6825"}],"version-history":[{"count":48,"href":"https:\/\/mixmotor.eu\/en\/wp-json\/wp\/v2\/posts\/6825\/revisions"}],"predecessor-version":[{"id":6880,"href":"https:\/\/mixmotor.eu\/en\/wp-json\/wp\/v2\/posts\/6825\/revisions\/6880"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mixmotor.eu\/en\/wp-json\/wp\/v2\/media\/6833"}],"wp:attachment":[{"href":"https:\/\/mixmotor.eu\/en\/wp-json\/wp\/v2\/media?parent=6825"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mixmotor.eu\/en\/wp-json\/wp\/v2\/categories?post=6825"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mixmotor.eu\/en\/wp-json\/wp\/v2\/tags?post=6825"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}