HOW TOYOTA VVTi ENGINE WORKS?
VVT-i, or Variable Valve Timing with intelligence, is an automobile variable valve timing technology developed by Toyota, similar to the i-VTEC technology by Honda. The Toyota VVT-i system replaces the Toyota VVT offered starting in 1991 on the 4A-GE 20-Valve engine. Perodua use this technology and convert the name to DVVT(Dynamic Variable Valve Timing). The VVT system is a 2-stage hydraulically controlled cam phasing system.
VVT-i, introduced in 1996, varies the timing of the intake valves by adjusting the relationship between the camshaft drive (belt, scissor-gear or chain) and intake camshaft. Engine oil pressure is applied to an actuator to adjust the camshaft position.
Engine designers have known for a long time that they could get better performance out of an engine under certain circumstances by allowing the intake valve to open slightly before the exhaust valve closes. This increases the time for the fuel/air mixture to enter the cylinder during the intake stroke. In this condition the exhaust and intake valves are open at the same time; this is called ‘valve overlap’. In conventional engines ‘valve overlap’ timing is fixed.
Fixed valve overlap allows the engine to perform well within a certain rev range, however there are three main undesirable side effects.
1) Fuel is wasted – the fuel/air mixture is not always efficiently burned and this causes unburnt fuel to pass through the engine.
2) Higher levels of undesirable exhaust emissions are produced.
3) Power output potential is not fully realised.
Variable valve timing allows the relationship between the separate inlet and exhaust camshafts to vary the valve timing overlap. In doing so it overcomes the side effects described above by using a computer to continuously vary the intake valve timing and overlap. The valve timing and overlap are adjusted through a series of simple mechanisms to ensure the optimum conditions apply across all the working rev range. The advantages are lower fuel consumption, lower exhaust emissions and higher power output. Because the system is continuously variable, an ‘i’ for ‘intelligent’ has been added to the acronym.
In 1998, “Dual” VVT-i (adjusts both intake and exhaust camshafts) was first introduced in the RS200 Altezza’s 3S-GE engine. Dual VVT-i is also found in Toyota’s new generation V6 engine, the 3.5L 2GR-FE V6. This engine can be found in the Avalon, RAV4, and Camry in the US, the Aurion in Australia, and various models in Japan, including the Estima. Dual VVT-i is also used in the Toyota Corolla (1.6 dual VVT-i 124bhp).
Other Dual VVT-i engines include the 1.8L 2ZR-FE I4, used in Toyota’s next generation of compact vehicles such as the Scion XD. It is also used in the 2JZ-GE and 2JZ-GTE engines used in the Lexus IS300 and in the Toyota Supra. By adjusting the valve timing engine start and stop occurs virtually unnoticeably at minimum compression. In addition fast heating of the catalytic converter to its light-off temperature is possible thereby reducing hydrocarbon emissions considerably.
(inside of vvti engine)
vvt-i= Variable Valve Timing-intelligent
i am interested to know more about new automobile technology
i wanna learn about the old school engine.they have a hidden potential………
may some one gimme the way how n where i can get the guider…….
where are the exactly right place or person i can refer to……please.
…………i’m the BEGINNER………
maybe you can try search via youtube.com about the engine operation
On a newly rebuilt 1.8L 1zz-fe, what would not allow oil to flow to the VVTi controller when the OCV and it’s screen has been replaced?
i have a toyota fun cargo with a 1nze engine and it burns more fuel than the ae 100 corolla wagon with a 5a engine
ive been using the vios 1.3 e in the Philippines. I found that the car can go up to 16km per liter. Whne you need power, the acceleration is very quick. as if you are driving a 1.6 engine while your engine is only 1.3 cc. When your going up in a hill or there;s 5 passenger , the car can go very fast. That’s the potential of VVT-i
so no point at all to purchase vios 1.6 .. ;)
Normally what models of cars is usually transplanted with 2JZ-GE engines? Could a Corolla SEG be fitted with the said engine?
Is Camry ideal for 2JZ-GE trasplant?
hi i know how the vvti engine works but i want to know if we use three cylinder instead of two cylinder above piston which is used for fule combution and creating pressure. if u can give me information then please contaqct me at mu email id
DVVT= dynamic variable valve timing is using by perodua not (dual)
well..
it so awsome..
can any body introduce us to the great engine creator..?!
n i wanna b as good as him/her..
n y don’t the ‘toyota’ creat a boat or a yatch from those great technology creat by the ‘toyota’..?!
hi im wondering why we dont set up all valve work with electric control .that save more gas and energy and more hp and faster engin work also repair engin be way esyer and lest cost (dosent need timeing belt/chain )
Just to share:
There are a couple of ways by which car manufacturer’s vary the valve timing. The most well known system is the VTEC which is used on some of the Honda engines. Other systems are:
* VarioCam/VarioCam Plus which is used on some of the Porsche engines,
* MIVEC(Mitsubishi Innovative Valve timing and lift Electronic Control) which is used on the Mitsubishi engines,
* VVT-i(Variable Valve Timing with Intelligence) and now VVTL-i (Variable Valve Timing and Lift with Intelligence) which is being used on the current Toyota and some Lexus engines,
* VVL(Variable Valve Lift) which is used on the Nissan engines and also featured in the 350Z is the CVTCS (Continuously Variable Valve Timing System)
* VANOS(Variable Onckenwellen Steuerung) which is used in the BMW engines and also the Double VANOS system on the new 3 Series and they are many more similar systems used by manufacturers such as Ford, Lamborghini and even Ferrari.
What do all these Vs have in common? Well, in case you don’t already know (or haven’t yet guessed despite the monster hint in the article’s title), the V stands for valves or, more specifically, variable valve timing.
Before you can appreciate how important valve timing is, you have to understand how it relates to engine operation.
Remember that an engine is basically a glorified air pump and, as such, the most effective way to increase horsepower and/or efficiency is to increase an engine’s ability to process air.
There are a number of ways to do this that range from altering the exhaust system to upgrading the fuel system to installing a less-restrictive air filter.
Since an engine’s valves play a major role in how air gets in and out of the combustion chamber, it makes sense to focus on them when looking to increase horsepower and efficiency.
Which engine system do u think is the best?
BMW’s VALVETRONIC/VANOS,
Mitsubishi’s MIVEC,
Nissan’s VVL
Subaru’s AVCS,
Toyota’s VVT-I,
Honda’s VTEC, and
Mazda’s S-VT ?
iwant know more about VVTI technology…n also about DVVT..can anyone mail me dis information to [email protected]
Kanyi. Your information is straight to the point thanks.
How good is the 1zz engine vvt-i found in the TOYOTA OPA.
What are the major advantanges of this type of engine and vvti
what is the best engine type that you would recomend for a new buyer of a toyota car coz i understand they come with acronames
Pliz friends are there any diesel propelled VVTi engines?
oke….
dream says:
June 23, 2010 at 10:12 am
Which engine system do u think is the best?
BMW’s VALVETRONIC/VANOS,
Mitsubishi’s MIVEC,
Nissan’s VVL
Subaru’s AVCS,
Toyota’s VVT-I,
Honda’s VTEC, and
Mazda’s S-VT ?
Ada lagi…
Proton’s Campro CPS
i work for many diferent mitsubishi engin none of thos have mivac disain any one knows wich model mitsubishi has mivac engine?
Actually that system just for performance only…not to reduce FC at all. Jusr drive Avanza 1.5G VVT-I…not really save it while driving, but it can also be set to accelerate the speed.
I love automobile work
Iam a student iam doing automotive engering i want to learn more about mechanics in motor industirie
Now, I’m finding to buy a Toyota Caldina 2002 model with VVTi Engine (1.8CC). So, i want to know the fuel consumption of that car. (How many Km/L)can drive. pls share your experiences. my E-mail is [email protected]
just want to know what is probably cause of the toyota vios vvt-i its is a hard starting first crank (fail to start) Second crank (fail start)sometimes reach 4 cranks to start the engine,, the engine good fuel pump, timing correct,
its affect the vvt-i in this case,,??
this is my e-mail – [email protected]
pls help me thanks….
thanks for getting this knolege of vvt i big up
Please, describes on details what is the advantages of vvt-i engines?
Please send me the animation of latest technology of automobiles.
I’m happy that VVT-i engene is nice one,
can you tell me what kind of toyota 4WD VVT-i engine i can buy
which can help on low fuel consuption?
my e-mail; [email protected]
Inform me about the topics i have highlighted please
which one fuel save for avanza,auto or manual.can auto engine convert to manual for avanza.tq.
2 Technologies are available for Variable Valve Timing, they have nothing to do with Toyota, one is the intake valve variant, the other is the exhaust valve variant, t both of these technology are developed more than 34 yrs ago by Alfa Romeo. Variable valve timing was first use in the 1978 Alfa Sprint Veloce. The combination of intake and exhaust comes about 3 yrs later also in an Alfa. The Japanese can only use VVTI after the lapse of copyright laws of 20 yrs, After trial and errors , Toyota start using VVT only in the early 90s, the “i” is added because of fuel injection(also not developed by Toyota).All in all ,the best design of all production engines using VVTI is still in European Cars, especially BMWs, where they have now added a timing dynamics using valve lenght instead of just the camshaft, even that was in the late 90s. The one with the variable valve lenght added is the Dual VVTI we hear today, in 1998 it was called Double Vanos in BMWs.
Guys! Which one is best betwn D-4 and VVTI engines.plz help mi thru [email protected]
I wanna know dtail about v v t -i would u please attach to my mail?
which one better, i-vtec or vvt-i technology?
I like cars and would like to laern
more on the technology that drives them…
Eh, apasal semua orang tak perasan sistem vvti instead puji, compare dan nak belajar. Aku play video kejap je. Suara latar video tu puji more efficient combustion? What do you mean efficient kalau masa piston sedang tolak (BDC ke TDC)ekzos keluar, injap masuk terbuka. Tak ke small portion ekzos akan masuk melalui injap masuk, pastu bila piston turun gas ekzos dah bercampur dgn oksigen=less oksigen utk next pembakaran.
Ole: teori kau betul kalau ekzos gas dan fuel mixture berada pada temparature yg sama.
tapi dlm kes internal combustion, gas ekzos panas dan fuel mixture sejuk. secara fizik, udara panas akan cepat naik ke atas dan udara sejuk akan cepat turun ke bawah.
maka dlm kes ni, gas ekzos akan naik dan keluar dgn cepat mengikut injap ekzos. gas ekzos akan susah nak pegi ke injap masuk sbb ada aliran masuk fuel mixture yg menolak ke dlm combustion.
fuel mixture yg dlm keadaan sejuk pulak dgn cepat akan turun ke bawah dan dlm masa yg sama membantu menolak gas ekzos ke atas.
Cal, aku masih kureng berpuas hati. Okeh, if instead teori oksigen, aku ada 3 argument lagi.
1. Sisa asap masih wujud dan bercampur. Dalam asap ada karbon. Perasan tak sifat karbon adalah menyerap. So petrol yang sepatutnya terbakar tidak terbakar dek kerana dah melekat kat zarah karbon.
2. Tekanan piston bukan rendah, at least 9.5 or 10:1. Equivalent pressure by 10 bar. So asap pasti akan masuk ke dalam injap masuk. Unless tekanan angin kat trottle body amat kuat or equivalent 10 bar jugak la
3. Teori gas panas cepat naik ke atas adalah kurang bersesuaian sebab kelajuan pembakaran adalah tersangat laju so gas panas sukar keluar dengan cepat jika tidak dibantu oleh piston. Same goes to udara sejuk yang nak dibawa masuk dalam kebuk pembakaran
1. Hasil pembakaran sempurna antara fuel+oksigen adalah karbon dioksida+air. Jadi kat sini bkn karbon sebaliknya karbon dioksida. Sifatnya tak sama. Kecuali yg terhasil adalah pembakaran tak sempurna, maka hasilnya karbon monoksida yg mmg dominan utk menyerap.
2. Tekanan masuk kena cari balik. Aku tak pasti.
3. Betul, combustion sgt laju, tapi proses circulation udara jgk sgt laju. Mcm puting beliung yg terhasil dari dua suhu yg sgt ekstrim menghasil putaran angin yg laju.
Ole: link ni adalah study paper yg ada explain pasal benefit of valve overlap. Hrp dpt jawab soalan ko.
http://www.mechadyne-int.com/vva-reference/papers/the-impact-of-variable-valve-actuation-on-engine-performance-and-emissions.pdf
Opening the intake valve before TDC can result in exhaust gasses flowing into the intake manifold instead of leaving the cylinder through the exhaust valve. The resulting EGR will be detrimental to full load performance as it takes up space that could otherwise be taken by fresh charge. EGR may be beneficial at part load conditions in terms of efficiency and emissions as discussed above.
Later intake valve opening can restrict the entry of air/fuel from the manifold and cause in-cylinder pressure to drop as the piston starts to descend after TDC. This can result in EGR if the exhaust valve is still open as gasses may be drawn back into the cylinder with the same implications discussed above. If the exhaust valve is closed, the delay of IVO tends not to be particularly significant, as it does not directly influence the amount of fresh charge trapped in the cylinder.
So dalam paperwork ni, aku paham 1 benda iaitu, konsep EGR diaplikasikan untuk vvti untuk reduce emission. But aku letakkan 1 persoalan lagi. Tapi bukan fasal system vvti. Tapi apa yang bakal terjadi pada injap masuk.
Untuk vvti, 1 perkara mesti dipatuhi iaitu, pembakaran adalah sempurna 100%. Kalau tak, mendakan karbon kering akan melekat kat injap masuk as well as injap keluar. Boleh bayangkan tak kenapa aku kata mcm ni?
ole: soalan ko mmg menarik. kalau internal combustion tak 100% clean, engine performance akan drop dgn mendadak. sbb hasil dia adalah C or CO yg mmg dominan menyerap dan block both valve.
maka, teknologi vvti ni memerlukan enjin berfungsi pada kadar paling optimum setiap masa utk hasilkan output optimum. kalau ada sikit defect mmg performance drop amat ekstrim.
bagi aku itu hukum karma, sama mcm investment. high risk, high return, low risk, low return ;)
Yeah, nothing perfect. Mcm ko ckp dulu la, dipersilakan cari perkara infiniti. Hehehe… Tapi arguement ni bagus juga untuk org2 yang guna enjin vvti ni. Jaga tul2 enjin anda. Kalau nampak asap hitam sikit je, cepat2 gi cek. Coz if performance dia drop, dia akan drop lebih teruk dari enjin biasa.
Aku agak confius gak mula2 tgk video tu. Mulanya ingat cam pakai konsep 2 lejang iaitu udara masuk akan tolak keluar asap
Aku ada 1 persoalan. Adakah produk decarbon dapat membuang semua karbon2 yang melekat kat injap masuk (if ada), injap keluar dan kebuk pembakaran
i hav a toyota camry2001 model with 2.5 litre engine n its fuel consumption is high, what can i do so that the fuel consumption is reduce. i m in TANZANIA.