AccueilGalerieRechercherS'enregistrerConnexionNouveaux messages depuis dernière visite
Rechercher
 
 

Résultats par :
 
Rechercher Recherche avancée
Qui est en ligne ?
Il y a en tout 53 utilisateurs en ligne :: 32 Enregistrés, 0 Invisible et 21 Invités :: 2 Moteurs de recherche

121212, alain combemale, bentou, Bighorn, Bolzzzz, Buell-LN, cat, commando, damienfollenfant, EDOUARD Jean, gee, hurricane, jhonguy, jmasse, LAFORJADELHERRERO, luigino.g, mitch82, Morisse, Neil, ONLYAM, philippe boeuf, Philippe HENRION, philwood, RDH2, SBRUGNERA, Seguela pascal, six for frog, Srx56, TOP DRIVER, tripotemascagne, tz125global, yves kerlo

Le record du nombre d'utilisateurs en ligne est de 294 le Lun 18 Nov 2019, 20:11
Derniers sujets
» Café Racer 800 DR couleur café
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 19:13 par Buell-LN

» [Oldies] Endurance Bol d'Or 1977 Le Mans
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 19:11 par tripotemascagne

» [Oldies] Charade 1974
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 18:56 par ducati63

» [Oldies] Quizz??????
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 18:43 par Ala Zorro

» (Oldies Endurance) 24 heures du Mans 1978, les premières...
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 18:21 par Dakota

» Transalp 1977, photos Roger Duvivier
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 18:17 par Dakota

» Renseignements sur Christian Dubuisson
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 17:50 par Seguela pascal

» vente bonhams
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 17:14 par lucky#45

» [Oldies] Les Suzuki 500 RG ( Part 2 )
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 12:56 par pascaltz

» Modification Cadre MALANCA.
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 12:47 par manx

» [Oldies] Les motos JBB, toute une histoire...
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 10:23 par Dialmax

» [WSBK] 2020
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 08:30 par MANETON

» [Oldies] 50cc de vitesse : Toute leur histoire ! (partie 2)
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeAujourd'hui à 08:18 par Simonini34

» [MotoGP] GP 2019 / 20 , infos , nouveautés , résultats des tests , potins et ....
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeHier à 20:19 par fullgazlolo

» [WSBK] phillip island 2020
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeHier à 11:35 par desmofr16

» [SORTIES] Bretagne moto classic 2020
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeHier à 11:21 par EDOUARD Jean

» [KlassGP 250 et 125] Saison 2020
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeHier à 10:15 par mickey

» [SORTIES] Salon du 2 roues à Lyon 13 au 16 février 2020
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeDim 23 Fév 2020, 08:07 par richardlemur

» [GP] MotoGP et télévision...
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeSam 22 Fév 2020, 01:55 par Noël

» [Oldies] Malheureusement, ils sont partis...
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeVen 21 Fév 2020, 21:02 par Hadock

» [Oldies] Honda 750 Daytona
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeVen 21 Fév 2020, 19:41 par philwood

» [Oldies] Daytona 1971
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeVen 21 Fév 2020, 18:38 par J-Chris

» [Techniques] Ça m’intéresse, composites et polymères
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeVen 21 Fév 2020, 14:20 par desmofr16

» [Oldies] Des livres sur la course moto
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeVen 21 Fév 2020, 11:08 par Pierre"PhilRead"

» [Technique châssis] Listing modèles de suspension AV
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeJeu 20 Fév 2020, 13:17 par nard gilles

» [MotoGP] Valentino Rossi, aujourd'hui...
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeJeu 20 Fév 2020, 09:42 par Srx56

» [Oldies] La coupe Kawasaki
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeJeu 20 Fév 2020, 08:55 par philippe7

» [Oldies] Mugello G.P d'Italie 05 1976
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeMer 19 Fév 2020, 20:42 par DidierF

» [GP] Johann Zarco
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeMer 19 Fév 2020, 20:13 par Mykeul

» [Moto2] NARD Ultra 6
Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeMer 19 Fév 2020, 19:12 par nard gilles

La réclame...
Mots-clés
yamaha bresse aermacchi charade 1973 geco ducati zone daytona rouge honda france ROAD 2013 race bourg wanted classic coupe RACING triumph eurosport suzuki side aprilia 1976
Meilleurs posteurs
Marc
Horizontal Exhaust Valves (or booster shut-off) Voting16Horizontal Exhaust Valves (or booster shut-off) Voting13Horizontal Exhaust Valves (or booster shut-off) Voting15 
philwood
Horizontal Exhaust Valves (or booster shut-off) Voting16Horizontal Exhaust Valves (or booster shut-off) Voting13Horizontal Exhaust Valves (or booster shut-off) Voting15 
EDOUARD Jean
Horizontal Exhaust Valves (or booster shut-off) Voting16Horizontal Exhaust Valves (or booster shut-off) Voting13Horizontal Exhaust Valves (or booster shut-off) Voting15 
Pierre"PhilRead"
Horizontal Exhaust Valves (or booster shut-off) Voting16Horizontal Exhaust Valves (or booster shut-off) Voting13Horizontal Exhaust Valves (or booster shut-off) Voting15 
mickey
Horizontal Exhaust Valves (or booster shut-off) Voting16Horizontal Exhaust Valves (or booster shut-off) Voting13Horizontal Exhaust Valves (or booster shut-off) Voting15 
Fügner
Horizontal Exhaust Valves (or booster shut-off) Voting16Horizontal Exhaust Valves (or booster shut-off) Voting13Horizontal Exhaust Valves (or booster shut-off) Voting15 
Jarno
Horizontal Exhaust Valves (or booster shut-off) Voting16Horizontal Exhaust Valves (or booster shut-off) Voting13Horizontal Exhaust Valves (or booster shut-off) Voting15 
yves kerlo
Horizontal Exhaust Valves (or booster shut-off) Voting16Horizontal Exhaust Valves (or booster shut-off) Voting13Horizontal Exhaust Valves (or booster shut-off) Voting15 
Dialmax
Horizontal Exhaust Valves (or booster shut-off) Voting16Horizontal Exhaust Valves (or booster shut-off) Voting13Horizontal Exhaust Valves (or booster shut-off) Voting15 
janpol84
Horizontal Exhaust Valves (or booster shut-off) Voting16Horizontal Exhaust Valves (or booster shut-off) Voting13Horizontal Exhaust Valves (or booster shut-off) Voting15 
La réclame...
-57%
Le deal à ne pas rater :
Friteuse à air chaud (sans huile)
64.99 € 149.99 €
Voir le deal

Partagez
 

 Horizontal Exhaust Valves (or booster shut-off)

Aller en bas 
AuteurMessage
Djamitague

Djamitague

Nombre de messages : 34
Localisation : Switzerland
Date d'inscription : 18/07/2014

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeDim 22 Mar 2015, 00:56

Does it exist an exhaust valve which slides horizontaly vs usual vertical valves? A sort of booster's shutter that'd affect surface vs timing.

[Vous devez être inscrit et connecté pour voir ce lien]
[Vous devez être inscrit et connecté pour voir ce lien]
Revenir en haut Aller en bas
Frits Overmars

Frits Overmars

Nombre de messages : 2285
Age : 71
Localisation : Raalte, Holland
Date d'inscription : 12/10/2010

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeDim 22 Mar 2015, 01:37

Djamitague a écrit:
Does it exist an exhaust valve which slides horizontaly vs usual vertical valves?
Yes, the Honda Power Port system, used in several CR125 and CR250 models.[Vous devez être inscrit et connecté pour voir ce lien] [Vous devez être inscrit et connecté pour voir ce lien]
Revenir en haut Aller en bas
Djamitague

Djamitague

Nombre de messages : 34
Localisation : Switzerland
Date d'inscription : 18/07/2014

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeDim 22 Mar 2015, 11:20

Quel cheni (What a mess)! Great pics thanks a lot Frits. That means in power valve systems we always influence timing, just widening the surface won't be effective?
Revenir en haut Aller en bas
Frits Overmars

Frits Overmars

Nombre de messages : 2285
Age : 71
Localisation : Raalte, Holland
Date d'inscription : 12/10/2010

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeDim 22 Mar 2015, 13:13

Djamitague a écrit:
Quel cheni (What a mess)! Great pics thanks a lot Frits. That means in power valve systems we always influence timing, just widening the surface won't be effective?
Not really. The 'problem' with a two-stroke is caused by the exhaust resonance. At the optimum rpm it sucks spent gases out of the cylinder and fresh mixture out of the crankcase. Some of the fresh mixture is sucked all the way into the exhaust duct, but right after the transfer ports are closed, a reflected pressure pulse from the exhaust pipe pushes this fresh mixture back into the cylinder, and then the piston closes the exhaust port.
But at 2/3 of the optimum rpm the pressure pulse arrives back at the cylinder when the transfer ports are still open. Then the fresh mixture in the exhaust duct and in the cylinder is pushed back into the crankcase with a disastrous effect on engine power.
If you want to improve this situation, you must open the exhaust port later, so the exhaust pulse starts later and comes back later. Narrowing the exhaust port will not change its timing, so it will not do much good for the power band.
Revenir en haut Aller en bas
JanBros



Nombre de messages : 264
Localisation : Belgique
Date d'inscription : 05/12/2011

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeDim 22 Mar 2015, 13:18

Frits Overmars a écrit:

If you want to improve this situation, you must open the exhaust port later, so the exhaust pulse starts later and comes back later. Narrowing the exhaust port will not change its timing, so it will not do much good for the power band.

if only we could do that scratch
Revenir en haut Aller en bas
Frits Overmars

Frits Overmars

Nombre de messages : 2285
Age : 71
Localisation : Raalte, Holland
Date d'inscription : 12/10/2010

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeDim 22 Mar 2015, 13:37

JanBros a écrit:
if only we could do that scratch
[Vous devez être inscrit et connecté pour voir ce lien] [Vous devez être inscrit et connecté pour voir ce lien]
This does not mean that I am in favor of a pneumatic operation for the power valve. It is a cheap solution, but not a very good one. It is governed by the mean pressure in the exhaust pipe, which drops during gear shifting, and, even worse, it also drops when the engine power drops due to very high revs. And the last thing you want then is to reduce the exhaust timing.
Reduced exhaust timing at low revs may broaden the power band by weakening the wrongly-timed exhaust resonance, but the best solution (apart from a CVT) is a trombone pipe.


Dernière édition par Frits Overmars le Dim 22 Mar 2015, 14:02, édité 1 fois
Revenir en haut Aller en bas
Institute of TwoStrokes



Nombre de messages : 148
Localisation : Australie
Date d'inscription : 15/10/2010

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeDim 22 Mar 2015, 13:59

The HPP system was so good that a few years later the RC valve made a triumphant return
Revenir en haut Aller en bas
Djamitague

Djamitague

Nombre de messages : 34
Localisation : Switzerland
Date d'inscription : 18/07/2014

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeDim 22 Mar 2015, 19:13

Frits Overmars a écrit:
Djamitague a écrit:
Quel cheni (What a mess)! Great pics thanks a lot Frits. That means in power valve systems we always influence timing, just widening the surface won't be effective?
Not really. The 'problem' with a two-stroke is caused by the exhaust resonance. At the optimum rpm it sucks spent gases out of the cylinder and fresh mixture out of the crankcase. Some of the fresh mixture is sucked all the way into the exhaust duct, but right after the transfer ports are closed, a reflected pressure pulse from the exhaust pipe pushes this fresh mixture back into the cylinder, and then the piston closes the exhaust port.
But at 2/3 of the optimum rpm the pressure pulse arrives back at the cylinder when the transfer ports are still open. Then the fresh mixture in the exhaust duct and in the cylinder is pushed back into the crankcase with a disastrous effect on engine power.
If you want to improve this situation, you must open the exhaust port later, so the exhaust pulse starts later and comes back later. Narrowing the exhaust port will not change its timing, so it will not do much good for the power band.

Ok so I guess pulse timing of the pipe does not vary so much regarding rpm. I thought its temperature would increase with rpm, thus wave speed in proportion(also depends on exhaust location and material...)
Revenir en haut Aller en bas
Frits Overmars

Frits Overmars

Nombre de messages : 2285
Age : 71
Localisation : Raalte, Holland
Date d'inscription : 12/10/2010

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeDim 22 Mar 2015, 23:13

Djamitague a écrit:
I guess pulse timing of the pipe does not vary so much regarding rpm. I thought its temperature would increase with rpm, thus wave speed in proportion(also depends on exhaust location and material...)
Generally speaking exhaust gas temperature increases with horsepower delivered, but not sufficiently so.
Hence the need for a variable ignition: later = hotter.
Revenir en haut Aller en bas
Niels Abildgaard



Nombre de messages : 35
Localisation : Denmark
Date d'inscription : 26/02/2013

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeLun 23 Mar 2015, 06:52

Frits Overmars a écrit:

Reduced exhaust timing at low revs may broaden the power band by weakening the wrongly-timed exhaust resonance, but the best solution (apart from a CVT) is a trombone pipe.

A pair or four exhaust valves VVT in head migth be more reliable than trombone?
Revenir en haut Aller en bas
Djamitague

Djamitague

Nombre de messages : 34
Localisation : Switzerland
Date d'inscription : 18/07/2014

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeLun 23 Mar 2015, 07:47

Is TROMBONE a moving pipe? Like the one I had on my MBK 51 in 1987 Very Happy
Revenir en haut Aller en bas
Frits Overmars

Frits Overmars

Nombre de messages : 2285
Age : 71
Localisation : Raalte, Holland
Date d'inscription : 12/10/2010

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeLun 23 Mar 2015, 10:52

Niels Abildgaard a écrit:
A pair or four exhaust valves VVT in head migth be more reliable than trombone?
Fourstroke-type valves in a two-stroke engine get too hot and open too slowly. They are only good for low power and low revs. But then why would you want the complication?

Djamitague a écrit:
Is TROMBONE a moving pipe? Like the one I had on my MBK 51 in 1987 Very Happy
Yep: [Vous devez être inscrit et connecté pour voir ce lien]
Revenir en haut Aller en bas
PVC

PVC

Nombre de messages : 166
Age : 72
Localisation : Chartres
Date d'inscription : 12/09/2011

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeLun 23 Mar 2015, 14:00

N'allez pas trop vite, j'ai du mal à traduire !

Quelqu'un pourrait-il me dire ce que veut dire "engine", ça m'aiderait.

Horizontal Exhaust Valves (or booster shut-off) 921866
Revenir en haut Aller en bas
Niels Abildgaard



Nombre de messages : 35
Localisation : Denmark
Date d'inscription : 26/02/2013

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeLun 23 Mar 2015, 14:25

Frits Overmars a écrit:
Niels Abildgaard a écrit:
A pair or four exhaust valves VVT in head migth be more reliable than trombone?
Fourstroke-type valves in a two-stroke engine get too hot and open too slowly. They are only good for low power and low revs. But then why would you want the complication?

Djamitague a écrit:
Is TROMBONE a moving pipe? Like the one I had on my MBK 51 in 1987 Very Happy
Yep: [Vous devez être inscrit et connecté pour voir ce lien]
[/quote]

Just dreaming of  better racing class criteria where two strokes were back and dominating.
The present racing two stroke was maybe its own worst enemy.
Plus 50 horsepower from something like 50 times 50 mm and an exhausts system so big  as the petrol tank has no real relation to people and chainsaws.
Total engine and exhaust volume and mass was maybe more meaningfull.
If exhaust is valved and therefore can be unsymetrical,the main job of exhaust system will be to get the used gas out.
I have dreamed a scheme where total engine volume and mass can maybe compete with the present form where mean effective pressure and piston speed is everything.

[Vous devez être inscrit et connecté pour voir ce lien]

Revenir en haut Aller en bas
Djamitague

Djamitague

Nombre de messages : 34
Localisation : Switzerland
Date d'inscription : 18/07/2014

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeLun 23 Mar 2015, 15:53

In term of dream, Guy Nègre designed a F1 engine head fit with a rotary valve shaft, supposed to support higher engine rev. But in a two stroke...? That's more or less a power valve
Revenir en haut Aller en bas
JanBros



Nombre de messages : 264
Localisation : Belgique
Date d'inscription : 05/12/2011

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeMar 24 Mar 2015, 08:17

JanBros a écrit:
Frits Overmars a écrit:

If you want to improve this situation, you must open the exhaust port later, so the exhaust pulse starts later and comes back later. Narrowing the exhaust port will not change its timing, so it will not do much good for the power band.

if only we could do that scratch

been thinking about this, but I don't get it. how can the valve provide assymetric open/closing times compared to BDC ?
unless the valve is so responsive it goes up and down with every stroke Horizontal Exhaust Valves (or booster shut-off) 55116
Revenir en haut Aller en bas
Frits Overmars

Frits Overmars

Nombre de messages : 2285
Age : 71
Localisation : Raalte, Holland
Date d'inscription : 12/10/2010

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeMar 24 Mar 2015, 10:57

I did not say anything about asymmetrical timing, Jan. I just said opening the exhaust port later would help, and we can easily accomplish that with a power valve.
Revenir en haut Aller en bas
Djamitague

Djamitague

Nombre de messages : 34
Localisation : Switzerland
Date d'inscription : 18/07/2014

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeMar 24 Mar 2015, 11:25

Djamitague a écrit:
Is TROMBONE a moving pipe? Like the one I had on my MBK 51 in 1987 Very Happy
Yep: [Vous devez être inscrit et connecté pour voir ce lien]
[/quote]
Hot stuff!
[Vous devez être inscrit et connecté pour voir ce lien]

Revenir en haut Aller en bas
JanBros



Nombre de messages : 264
Localisation : Belgique
Date d'inscription : 05/12/2011

Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitimeMar 24 Mar 2015, 23:12

Frits Overmars a écrit:
I did not say anything about asymmetrical timing, Jan.

you are right, don't know how come I read it that way scratch
Revenir en haut Aller en bas
Contenu sponsorisé




Horizontal Exhaust Valves (or booster shut-off) Empty
MessageSujet: Re: Horizontal Exhaust Valves (or booster shut-off)   Horizontal Exhaust Valves (or booster shut-off) Icon_minitime

Revenir en haut Aller en bas
 
Horizontal Exhaust Valves (or booster shut-off)
Revenir en haut 
Page 1 sur 1
 Sujets similaires
-
» une recette simple pour booster!
» Booster de NO
» Résister au Vélo Horizontal, oui mais avec quels arguments ?
» Choix d'un vélo horizontal : Nazca Pioneer ?
» PBP en Vélo Horizontal

Permission de ce forum:Vous ne pouvez pas répondre aux sujets dans ce forum
 :: ACTUALITES :: [GP] :: [GP125 (et 250 Snif!)]-
Sauter vers: