Što je Vtec i kako on funkcinira?!

<	lipanj, 2006					>
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Yoyokagirinaku tainichi

Soul Of JAPAN

HONDA POWER OF DREAMS

Mjau
Z
Ludi
Rambo
Kolega z vaxa
Darko z vaxa

Honda Song
Feel free to sing along
I love my Honda like I love my ganja
I’ll smoke ya v-8 like I smoke marijuana
Back up boy and show some respect
My Honda civic has a 4 cylinder vtec
When I go out people wanna see my ride
They always stare at the "Type R" on the side
I painted my hood black for that carbon fiber look
My windshield wiper lights that off tha fuckin hook
I took off my hubcaps cause they give me better times
When I rip a new track I’m stunnin on my rhymes
My exhaust turned sideways with a 5 inch tip
I raced a z06 and took home his pink slip
I got a new spoiler from J.C. whitney
It's a 15 inch doublestak worth every penny
APC decals and two racing stripes
4 ion blue daytime runiing lights
When I take off tha front tires go up in smoke
And chevy’s with 350’s ain’t nothing but a joke
Went to Pep Boys and bought all the neon lights
Its like Las Vegas when you see me at night
Don’t mess with tha vtec cause it’ll send ya home
Cryin lika fat kid that dropped his ice cream cone
When ya see my comin get outta my way
I gotta cruise tha mall cause you know its Friday
I doing loud fly-bys all down tha highway
Bumping some techno with my visor turned sideways
If you wanna race ya ass will get tossed
I throw in it neutral and rev up the exhaust
I’m gonna leave your ass in a world on pain
My adrenaline rushin with tha rice in my veins
Nutra slam it in drive when the light turns green
And I’ll eat a Saleen like ya momma lean cusine
I got another victory in the "domestic basher"
I’ll pull in front of you and throw on my flashers
When ya lost you called me a cheater
Ya just couldn't hang with the 1.6 liter
Tha Civic is more like a rocket than it is a car
You’ll be sayin to ya self “damn is that a type R”
(Fast & Furious interlude)
Don’t mess with Hondas cause they’re outta ya class
I wait till ya get beside me trying ta pass
Let ya hear tha vtec when I step on tha gas
Next thing ya know your ass is finishin last
I fix you a "Type R" burger with some vtec sauce
You’re ass will be fired cause Honda is tha boss
Is NOT called nitrious tha shit is called called NOS
You should know by now your life is a loss
It’s about time you stop driving all them wrecks
Get a job at hardees and save all ya checks
Or sue KFC for falling on ya neck
And when you get paid buy yourself a Vtec

END.......

Tvoja nježna koža s pudera tri kile
Mekša je od kostrijeti, al ne i od svile

Tvoje oči buljave iza debelih stakala
Kriju tonu krmelja i korijen svih zala

Bokovi ti širi od brodogradilišta brojnih
Kud te samo nađoh, prišteva ti gnojnih

Debljina je tvoja opasnija od mine
Iz tangi se šire mirisi sardine

Ali nisi ti loša, moja mračna draga
Iako si gadna i ružnija od vraga

Svaka tvoja prljavština, malformacija i mana
Samo dodatno zateže mog nabreklog organa

Povest cu te kući stare svoje majke
Kad nas vidi zajedno, odapet će papke

Pa ćemo da živimo, oko nas zlo i grijeh
Ja vam kažem - to je ljubav, a ne samo peh

Al mi dosadi i prođe me manija -
cijelo vrijeme drkala je na Filta Danija

Htjela je tamu, sotona i slavu
Sad je drolja dobila motiku u glavu

Kupih si Smokvin list i rolnu papira
Vidite da drkam, dajte malo mira.

Kupila je majicu od blek metal benda
Počela je glasnije i više da serenda

Mazala se crnim, ko dimnjačar izgledala
Šminkala se po tri sata, al se nije brijala

Dobila je novi kaiš, da krasi bokove njene
Od titana i celika - da izdrži opterecenje

Sise je izbacila, a trbuh uvukla
Došlo je do implozije, slezena joj napukla

Vodismo ju kod doktora da joj liječi rane
Kad joj škembu razreza, njemu pogled stane

Jadan doktor ne zna da zove sad koga -
Vidje u njoj netko vrišti "spasi, ako znadeš Boga!"

Bijaše to mladi momak, krv mu mladom vrela
Ribarom je podmazan, pa je na njeg sjela

Uvukla ga u sebe, ko dim od Benstona
Nosila ga na srcu da joj pjeva Mansona

Izvuče ga doktor, pita "jesil karo?"
A veli mu momak "ne bi da sam znao"

Po koži mu sve kraste, kosti mu se vide
Dobio je sifilisa, kapavca i SIDE

Veli njemu doktor i gleda ga mrko
"Bolje da si, mladiću, osto kuci drko!"

Zdena na sudu

Smjestila se priča međ' Papuk i Dravu
Gdje se Zdeni sudi po krivičnom pravu

Optužnica glasi: Ševljenje sa volom
i to zamislite - pred osnovnom školom

Gnjevni stanovnici, uplašena djeca
na radiju komentira prodavač pereca

Pošli smo do zatvora da vidimo Zdenu
kad nam vidla kite, tiho suze krenu

Što ću jadna sada, nemam pristup kari
čak su mi i vola odveli čuvari

Vol je kriv ko i ti - veli tip u plavom
bolje man' se kurca, mućni malo glavom!

Došo dan suđenja, nemile li scene
vidjet silne lance oko gole Zdene

Na ustima povez pored nogu džukac
tužitelj je likovao, kad prozbori sudac:

Što je ovo ljudi? Nek' se brnj'ca makne!
neće valjda džukcu ovome da sakne!?

Ne znate vi zdenu, tužitelj će kivno
a u sebi misli - to će biti divno.

Skinuli joj povez, a Zdena k'o Zdena
pred službenog džukca pade na koljena

I dok mu je nježno milovala guzu
narod je urlikao: Vodi je u ćuzu!

Pomislili i mi: Sad joj nema spasa,
kadli ono sudac poče da se glasa

Uh, kako me ova sočna pica vabi
dođi malo amo, na nos mi ju nabi!

Tužitelj se drao - ovo je presedan!
kakav si ti sudac? Pohotniče jedan!

Kušuj tamo, svinjo! - odgovori sudac
vidiš da mi mala dodiruje kurac!

A vi glupi ljudi, što ste žedni krvi,
idite do vola on je krivac prvi!

I nesretni vol ostade bez muda,
a Zdena i sudac odu - nitko ne zna kuda

VIC JE KRAJ SVIJETA.....

U Ljubljani na terasi jednog hotela, Hrvat doruckuje šnitu kruha sa marmeladom.

Dolazi do njega Janez i žvače žvakaču.

Pita njega Janz:

-Ali pa vi pojeste celo šnito hruha?

Hrvat mu odgovori:

-Da.

Veli Janez:

-Mi pa ne. Mi pojemo samo sredino in trdo koro bacimo v reciklažo. Potem pa od tega napravimo dvopek in ga prodamo Hrvatima.

Nastavi Janez žvakati žvakaću i opet pita Hrvata:

-Ali pa vi pojeste celo marmelado?

Hrvat odgovori:

-Da.

Janez mu veli:

-Mi pa ne. Mi pojemo samo tisto v marmeladi kaj je mehko, a koščice in koro bacimo v reciklažo. Potem pa to recikliramo in prodamo Hrvatom.

Janez nastavi žvakati žvakaću, a Hrvat njega pita:

-Da li se vi Slovenci seksate?

-Se vedno da da. (I nastavi žvakati)

-I šta radite s upotrebljenim prezervativima?

-Je kaj...? Jih pa bacimo.

-E vidiš, mi ih recikliramo, pa od njih napravimo žvakače gume i prodamo ih Sl

04.06.2006., nedjelja

VTEC (standing for Variable valve Timing and lift Electronic Control) is a system developed by Honda to improve the combustion efficiency of its internal combustion engines throughout the RPM range. This was the first system of its kind and eventually led to different types of variable valve timing and lift control systems that were later designed by other manufacturers (VVT-i from Toyota, VANOS from BMW, and so on). It was invented by Honda's chief engine designer Kenichi Nagahiro.
Contents

Introduction to VTEC

In the regular four-stroke automobile engine, the intake and exhaust valves are actuated by lobes on a camshaft. The shape of the lobes determines the timing, lift and duration of each valve. Timing refers to when a valve is opened or closed with respect to the combustion cycle. Lift refers to how much the valve is opened. Duration refers to how long the valve is kept open. Due to the behavior of the gases (air and fuel mixture) before and after combustion, which have physical limitations on their flow, as well as their interaction with the ignition spark, the optimal valve timing, lift and duration settings under low RPM engine operations are very different from those under high RPM. Optimal low RPM valve timing, lift and duration settings would result in insufficient fuel and air at high RPM, thus greatly limiting engine power output. Conversely, optimal high RPM valve timing, lift and duration settings would result in very rough low RPM operation and difficult idling. The ideal engine would have fully variable valve timing, lift and duration, in which the valves would always open at exactly the right point, lift high enough & stay open just the right amount of time for the engine speed in use.

In practice, a fully variable valve timing engine is difficult to design and implement. Attempts have been made, using solenoids to control valves instead of the typical springs-and-cams setup, however these designs have not made it into production automobiles as they are very complicated and costly.

The opposite approach to variable timing is to produce a camshaft which is better suited to high RPM operation. This approach means that the vehicle will run very poorly at low rpm (where most automobiles spend much of their time) and much better at high RPM. VTEC is the result of an effort to marry high RPM performance with low RPM stability.

Additionally, Japan has a tax on engine displacement, requiring Japanese auto manufacturers to make higher-performing engines with lower displacement. In cars such as the Supra and 300ZX, this was accomplished with a turbocharger. In the case of the RX-7, a wankel engine was used. VTEC serves as yet another method to derive very high specific output from lower displacement motors.

DOHC VTEC

Honda's VTEC system is a simple method of endowing the engine with multiple camshaft profiles optimized for low and high RPM operations. Instead of one cam lobe actuating each valve, there are two - one optimized for low RPM stability & fuel efficiency, with the other designed to maximize high RPM power output. Switching between the two cam lobes is determined by engine oil pressure, engine temperature, vehicle speed, and engine speed. As engine RPM increases, a locking pin is pushed by oil pressure to bind the high RPM cam follower for operation. From this point on, the valve opens and closes according to the high-speed profile, which opens the valve further and for a longer time. The DOHC VTEC system has high and low RPM cam lobe profiles on both the intake and exhaust valve camshafts.

The VTEC system was originally introduced as a DOHC system in the 1989 Honda Integra sold in Japan, which used a 160 hp (119 kW) variant of the B16A engine. The US market saw the first VTEC system with the introduction of the 1990 Acura NSX, which used a DOHC VTEC V6. DOHC VTEC motors soon appeared in other vehicles, such as the 1992 Acura Integra GS-R.

SOHC VTEC

As popularity and marketing value of the VTEC system grew, Honda applied the system to SOHC engines, which shares a common camshaft for both intake and exhaust valves. The trade-off is that SOHC engines only benefit from the VTEC mechanism on the intake valves. This is because in the SOHC engine, the spark plugs need to be inserted at an angle to clear the camshaft, and in the SOHC motor, the spark plug tubes are situated between the two exhaust valves, making VTEC on the exhaust impossible.

SOHC VTEC-E

Honda's next version of VTEC, VTEC-E, was used in a slightly different way; instead of optimising performance at high RPMs, it was used to increase efficiency at low RPMs. At low RPMs, only one of the two intake valves is allowed to open, increasing the fuel/air atomization in the cylinder and thus allowing a leaner mixture to be used. As the engine's speed increases, both valves are needed to supply sufficient mixture. A sliding pin, as in the regular VTEC, is used to connect both valves together and allows opening of the second valve.

3-Stage VTEC

Honda also introduced a 3-stage VTEC system in select markets, which combines the features of both SOHC VTEC and SOHC VTEC-E. At low speeds, only one intake valve is used. At medium speeds, two are used. At high speeds, the engine switches to a high-speed cam profile as in regular VTEC. Thus, both low-speed economy and high-speed efficiency and power are improved.
i-VTEC

i-VTEC introduced continuously variable camshaft phasing on the intake cam of DOHC VTEC engines. The technology first appeared on Honda's K-series four cylinder engine family in 2002. Valve lift and duration are still limited to distinct low and high rpm profiles, but the intake camshaft is now capable of advancing between 25 and 50 degrees (depending upon engine configuration) during operation. Phase changes are implemented by a computer controlled, oil driven adjustable cam gear. Phasing is determined by a combination of engine load and rpm, ranging from fully retarded at idle to maximum advance at full throttle and low rpms. The effect is further optimization of torque output, especially at low and midrange RPMs.

In 2004, Honda introduced an i-VTEC V6 (an update of the venerable J-series), but in this case, i-VTEC had nothing to do with cam phasing. Instead, i-VTEC referred to Honda's cylinder deactivation technology which closes the valves on one bank of (3) cylinders during light load and low speed (below 80 mph) operation. The technology was originally introduced to the US on the Honda Odyssey, and can now be found on the Honda Accord Hybrid and the 2006 Honda Pilot. An additional version of i-VTEC was introduced on the 2006 Honda Civic's R-series four cylinder engine. This implementation uses very small valve lifts at low rpm and light loads, in combination with large throttle openings (modulated by a drive-by-wire throttle system), to improve fuel economy by reducing pumping losses.

With the continued introduction of vastly different i-VTEC systems, one may assume that the term is now a catch all for creative valve control technologies from Honda.

Turbocharged VTEC

For 2007 models, Honda's Acura luxury division announced the RDX crossover SUV which will feature a new turbocharged 2.3 litre inline 4 cylinder i-VTEC engine. While Honda (previous examples include the Honda City Turbo and City Turbo II) and the first time to an engine with i-VTEC.

VTEC in motorcycles

Apart from the Japanese market-only Honda CB400 Super Four Hyper VTEC, introduced in 1999, the first worldwide implementation of VTEC technology in a motorcycle occurred with the introduction of Honda's VFR800 sportbike in 2002. Similar to the SOHC VTEC-E style, one intake valve remains closed until a threshold of 7000 rpm is reached, then the second valve is opened by an oil-pressure actuated pin. The dwell of the valves remains unchanged, as in the automobile VTEC-E, and little extra power is produced but with a smoothing-out of the torque curve. Critics maintain that VTEC adds little to the VFR experience while increasing the engine's complexity. Drivability is a concern for some who are wary of the fact that the VTEC may activate in the middle of an aggressive corner, upsetting the stability and throttle response of the bike.

The VTEC experience

VTEC is fairly seamless in its operation. That is, when the VTEC system switches to the other cam lobe, there is hardly a noticeable drop-off or sudden increase in power. The basis of VTEC technology is that a very linear and smooth power curve can be attained, hence a "sudden rush of power" simply does not happen (like with a turbocharger suffering from "lag"). This is one of the many misconceptions with Honda's VTEC technology, and variable valve timing in general. However, when modified with aftermarket parts such as high-flow air intakes and larger camshafts, the switch to the large lobes can be very pronounced. There can be a mild kick in the pants in the lower gears, though this is certainly amplified by the sound the DOHC VTEC engines produce at the upper spectrum of the RPM range.

Driving a vehicle with VTEC can require additional driver input. In particular, the Honda S2000 has received complaints from both owners and detractors due to its very high (9,000 rpm) redline in the early models. While the engine produces very high output (120hp per litre), some see the continual need to "row the gears" as a distraction from driving.

- 16:25 - Komentari (34) - Isprintaj - #

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