мислам дека е вака 
4 вентили на клип, два усисни два издувни. На високи вртежи отворени се сите 4 а на пониски еден усисен и еден издувен. Со тоа штедат гориво
Не е така...еве copy-paste, де не пишувам цел ден...
What is Twinport ? Twinport This question comes up now and again answers are mixed and occasionally confused due to sources on the internet not making sense.
Basically this thread will describe what Twinport is, that is to say, just the Twinport technology, nothing else that is included on the new Twinport engines such as the enhanced EGR system, this is just about the Twinport mechanism, how it works and why it's used.
Background on emissions The first point to note is that the engine has been designed to conform to emissions regulations and to be efficient and driveable. To ensure low emissions you want to reduce the amount of un-burnt fuel that goes through the exhaust. To ensure the maximum amount of fuel gets burnt it must have enough time in the cylinder to mix with the air, and it must have the right amount of air in the cylinder ideally a bit lean and with a good mixture composition. The amount of time is determined by engine speed, which is low for the emissions regulation checks. The volumetric efficiency of the air and the composition of the air-fuel mixture, is influenced heavily by inlet design. Now that you understand what is required to ensure low emissions you will have a better understanding of Twinport technology.
What is it in simple terms? Twinport technology simply put involves partially blocking off one of the two inlet ports on each cylinder at low engine speeds. The 4 valve per cylinder engine design shows why there are two inlet ports.
How does it work ?
Twinport works by a spring loaded acctuator contracting at high rpm. At rest and low RPM the valve is left out. This acctuator controls (by way of a plastic rail) the 4 metal plates in each of the inlet port pairs.
My hand is controlling the spring loaded valve at this point, pushing it in moves the flaps up, letting it out let’s them fall to their default position.
Default Closed position at low RPM < ≈ 3000
The pressure difference between the cylinder and inlet tract is what causes the air to rush towards the cylinder. As the inlet valve opens there is a vacuum in the cylinder compared with the ambient pressure, this causes air to rush in, thus filling the cylinder. This is why the air tries to travel with a constant mass flow rate. Mass flow rate is the product of air density, velocity and the area through which the matter is flowing. The area has clearly decreased through blocking off one port. Therefore to maintain a constant mass flow rate of air the velocity must increase.
This faster moving air improves the low engine speed volumetric efficiency of the engine due to the increased inertia of the air (due to the increased velocity) resulting in greater amounts of air filling the cylinder after the piston has reached BDC. With the fixed cam timing on the engine after BDC as the piston rises air is forced out of the closing inlet valve. With increased air interia from the faster moving flow, air can continue to fill the cylinder or at least slow down the rejection of air from the cylinder, resulting in a greater amount of air in the cylinder during the compression phase.
This faster moving air induces turbulence as it travels through the inlet pipework. Extra turbulence is caused by the blocked port. This excited turbulent air is easier to mix with fuel particles. This results in more air and more fuel being mixed at the same time (homogeneous mxiture). The more turbulent tumble of the air fuel mixture inside the cylinder also promotes a more turbulent flame front upon ignition which also improves the burn phase of the fuel and subsequently reduces emissions.
This reduces emissions as un-burnt fuel containing hydrocarbons is not being wasted. Fuel economy increases, emissions drop and you can get a possible torque increase at low RPM compared to Non-Twinport. In this writers opinion it is other changes made to the newer engine through changed engine geometry, cam and head design which directly alter the peak bhp value.
Midway
This picture is just showing the path the block off plate will take. Note the holes in the plate are to ensure that the air does not get backed up . If it were completely solid it may result in the airflow of the system being slower than is required. The holes in the plates allow for excess which has gone down the blocked off channel to vent around it. A solid plate might stall the airflow and could slow the neighbouring airThe transition between this phase and the next “open” phase happens almost instantaneously it is only to show the mechanism.
Open – High RPM > ≈ 3000
At this engine speed the airflow is high enough to sustain proper air-fuel mixing, and any blockage reduces volumetric efficiency. This is combined with the fact that the engine speed is out of emissions testing regulations so it’s not required to provide perfect air-fuel ratio.
TwinportU vrijeme kad se vodi velika polemika oko direktnog ubrizgavanja benzina, isplativosti i tržišne budućnosti tog sustava, dobro se podsjetiti da Opelov sustav indirektnog ubrizgavanja u dva mlaza - Twinport, na mnogo jednostavniji i jeftiniji način donosi većinu efekata direktnog ubrizgavanja.
Konkretno - za manje od četvrtinu cijene najavljenog sustava direktnog ubrizgavanja benzina Bosch DI-Motronic, nudi gotovo tri četvrtine njegovih efekata. Posebice to dolazi do izražaja kod manjih motora, kod kojih preskupa i prezahtjevna tehnologija direktnog ubrizgavanja nije isplativa. Time su zorno pokazali kako uvijek nije najbolje ono što je najkompliciranije i najskuplje. Opelova tehnologija ima znatno manje problema s dušikovim oksidima (NOx), koji su rak-rana direktnoubrizgavajućih benzinaca.
Twinport na znatno jednostavniji i jeftiniji način štedi gorivo od zahtjevnog i skupog direktnog ubrizgavanja. Za četvrtinu cijene sustava Bosch DI-Motronic nudi tri četvrtine njegovih efekata
Gorivo se može ubrizgavati indirektno (u usisnu cijev) i direktno (u cilindar). Kod indirektnog ubrizgavanja (u 99 posto benzinskih motora) miješanje počinje u usisnoj cijevi, te se nastavlja u cilindru tijekom usisa i kompresije. Pri kraju kompresije, prije preskakanja iskre na svjećici, postiže se homogena smjesa goriva i zraka. Kod direktnog ubrizgavanja sve se odvija u cilindru. Zanimljiva koncepciju indirektnog ubrizgavanja Twinport ujedinjuje prednosti svih koncepcija ubrizgavanja te osigurava stehiometrijski omjer gorive smjese (14,7 g zraka : 1 g goriva) u cjelokupnom području, osim u praznom hodu i kod punog opterećenja.
Teillast - djelomično opterećenje: brizgaljka 5 ubrizgava većinu goriva kroz otvoreni kanal 3, a drugi je zatvoren zaklopkom za zrak 3. Time se postiže vrtloženje usisne smjese, što je pogodno za izgaranje kod manjeg opterećenja. Volllast - puno opterećenje: uaklopka oslobađa usis zraka i za drugi usisni kanal te usisna smjesa izravno ustrujava u cilindar, što je povoljno kod velikog opterećenja
Usisna je cijev blizu ulaska u cilindar razdijeljena: ravni usisni kanal zadužen je za punjenje, a zakrivljenji za vrtloženje smjese Turbulencije smjese bitno poboljšavaju izgaranje i taj je kanal uvijek otvoren. Uz njega je postavljen kanal za punjenje, koji je poprečno pregrađen leptirastom zaklopkom. Posebno razvijena brizgaljka ubrizgava dva kompaktna mlaza u svaki usisni kanal posebno. Usisnu zaklopku u kanalu za punjenje okreće vakuumski uređaj (4), na temelju podtlaka u središnjoj usisnoj cijevi iza glavne usisne zaklopke. Kod malih brzina vrtnje i opterećenja (kad je velik podtlak iza glavne usisne zaklopke) kanal za punjenje potpuno se zatvara te je punjenje samo preko vrtložnog kanala.
Indirektno ubrizgavanje po sustavu Twinport učinkovito je kod manjih i srednjih motora, te ga Opel zasad koristi u benzincima 1.0(60 KS, 1.2/80 KS, 1.4/90 KS i 1.6/105 KS
Tako se pojačava vrtloženje u cilindru te se i kod male brzine vrtnje ostvaruje kvalitetno izgaranje. Kod velikih brzina vrtnje i opterećenja nestaje podtlak iza glavne usisne zaklopke, te opružni mehanizam vraća zaklopku u početni (otvoreni) položaj. Tada motor diše punim plućima te mu puno ne smeta što je ubrizgavanje indirektno. Učinkovito vrtloženje usisne smjese omogućava miješanje i do 30 posto ispušnih plinova preko EGR-ventila. Tako se osjetno smanjuje količina dušikovih oksida u ispušnim plinovima te Opelovi benzinci nove generacije Ecotec Twinport bez problema zadovoljava norme Euro 4, a imaju potencijal i za Euro 5, koje stupaju na snagu 1. 9. 2009. godine.
A sada osnovno o direktnom ubrizgavanju...
Kod direktnog ubrizgavanja koristi se trik - slojevito punjenje. Lokalno, u blizini svjećice postiže se pravilna ili bogata smjesa, a u ostalom, većem dijelu cilindra siromašna. Inicijalni požar, nastao uz više goriva, brzo se širi na cijeli cilindar. No, ušteda se postizala samo kod manjeg opterećenja
Bosch DI-Motronic je sustav direktnog ubrizgavanja druge generacije preko sustava zajedničkog voda (common-rail), a najvažnija su novost piezo-brizgaljke, koje maksimalne tlakove ubrizgavanja, sa sadašnjih 120, povisuju na 200 bara. Novorazvijene sapnice, po uzoru na dizelske, imaju niz kružno postavljenih rupica, kroz koje se gorivo, u dva do tri impulsa, u cilindar ubrizgava u fino raspršenom, stožastom mlazu
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