Vanos

[mrhartge]

VANOS is a combined hydraulic and mechanical camshaft control device managed by the car's DME engine management system. The VANOS system is based on an adjustment mechanism that can modify the position of the intake camshaft versus the crankshaft. Double-VANOS adds an adjustment of the intake and outlet camshafts.VANOS operates on the intake camshaft in accordance with engine speed and accelerator pedal position. At the lower end of the engine-speed scale, the intake valves are opened later, which improves idling quality and smoothness. At moderate engine speeds, the intake valves open much earlier, which boosts torque and permits exhaust gas re-circulation inside the combustion chambers, reducing fuel consumption and exhaust emissions. Finally, at high engine speeds, intake valve opening is once again delayed, so that full power can be developed.VANOS significantly enhances emission management, increases output and torque, and offers better idling quality and fuel economy. The latest version of VANOS is double-VANOS, used in the new M3.VANOS was first introduced in 1992 on the BMW M50 engine used in the 5 Series. Here's how it works: In overhead cam engines, the cams are connected to the crankshaft by either a belt or chain and gears. In BMW VANOS motors there is a chain and some sprockets. The crankshaft drives a sprocket on the exhaust cam, and the exhaust cam sprocket is bolted to the exhaust cam. A second set of teeth moves a second chain that goes across to the intake cam. The big sprocket on the intake cam is not bolted to the cam, for it has a big hole in the middle. Inside the hole is a helical set of teeth. On the end of the cam is a gear that is also helical on the outside, but it's too small to connect to the teeth on the inside of the big sprocket. There is a little cup of metal with helical teeth to match the cam on the inside and to match the sprocket on the outside. The V (Variable) in VANOS is due to the helical nature of the teeth. The cup gear is moved by a hydraulic mechanism that works on oil pressure controlled by the DME.

At idle, the cam timing is retarded. Just off idle, the DME energizes a solenoid which allows oil pressure to move that cup gear to advance the cam 12.5 degrees at midrange, and then at about 5000 rpm, it allows it to come back to the original position. The greater advance causes better cylinder fill at mid rpms for better torque. The noise some people hear is the result of tolerances that make the sprocket wiggle a bit as the cup gear is moved in or out. Double VANOS-------------------------------------------------------------------------------Double-VANOS (double-variable camshaft control) significantly improves torque since valve timing on both the intake and outlet camshafts are adjusted to the power required from the engine as a function of gas pedal position and engine speed.

On most BMW engines that use a single VANOS, the timing of the intake cam is only changed at two distinct rpm points, while on the double-VANOS system, the timing of the intake and exhaust cams are continuously variable throughout the majority of the rpm range. With double-VANOS, the opening period of the intake valves are extended by 12 degrees with an increase in valve lift by 0.9 mm. Double-VANOS requires very high oil pressure in order to adjust the camshafts very quickly and accurately, ensuring better torque at low engine speeds and better power at high speeds. With the amount of un-burnt residual gases being reduced, engine idle is improved. Special engine management control maps for the warm-up phase help the catalytic converter reach operating temperature sooner. Double-VANOS improves low rpm power, flattens the torque curve, and widens the powerband for a given set of camshafts. The double-VANOS engine has a 450 rpm lower torque peak and a 200 rpm higher horsepower peak than single-VANOS, and the torque curve is improved between 1500 - 3800 rpm. At the same time, the torque does not fall off as fast past the horsepower peak. The advantage of double-VANOS is that the system controls the flow of hot exhaust gases into the intake manifold individually for all operating conditions. This is referred to as "internal" exhaust gas re-circulation, allowing very fine dosage of the amount of exhaust gas recycled. While the engine is warming up, VANOS improves the fuel/air mixture and helps to quickly warm up the catalytic converter to its normal operating temperature. When the engine is idling, the system keeps idle speeds smooth and consistent thanks to the reduction of exhaust gas re-circulation to a minimum. Under part load, exhaust gas re-circulation is increased to a much higher level, allowing the engine to run on a wider opening angle of the throttle butterfly in the interest of greater fuel economy. Under full load, the system switches back to a low re-circulation volume providing the cylinders with as much oxygen as possible.

 

[ICEMAN 68]

kewl article ....

for thani what sort of vanos is there in the stomach ?

 

[mrhartge]

Originally posted by ICEMAN 13@Jun 1 2005, 11:32 AM
kewl article ....

for thani what sort of vanos is there in the stomach ?

kilkenny lar.....

 

[Zoggee]

and I heard someone replace his M50 vanos kit for more then 1K..!! for an M50 engine. Crazy ah..!!?? My bro's M52B28 Vanos kit doesn't cost that much... B)

 

[teejay]

penang kia parts sure expensive wat.......

u from there u know lar.....

have to pay extra for the kilkenny bits.....

 

[mrhartge]

Originally posted by teejay@Jun 2 2005, 12:24 AM
penang kia parts sure expensive wat.......

u from there u know lar.....

have to pay extra for the kilkenny bits.....

zonggee isnt tokin about me lar...haiyoo....

 

[naza2]

i love vanos..

and i also like the ass in your avatar. got some?

 

[mafia]

Originally posted by naza2@Jun 2 2005, 11:20 PM
i love vanos..

and i also like the ass in your avatar. got some?

muahahahahaha

 

[mrhartge]

Originally posted by naza2@Jun 2 2005, 11:20 PM
i love vanos..

and i also like the ass in your avatar. got some?

wei engine tech lar...wanna hijack go to autobahn lar....

 

[wann77]

Is VANOS functions just like VTEC for japs HONDA? :unsure:

 

[mrhartge]

Originally posted by wann77@Aug 3 2005, 04:59 PM
Is VANOS functions just like VTEC for japs HONDA? :unsure:

same principals but technically different....as u can see below

VTEC
VTEC (standing for Variable valve Timing and lift Electronic Control) is a system developed by the car manufacturer Honda to improve the combustion efficiency of its internal combustion engines throughout the RPM range.


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' determine both the timing and the lift 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. 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 and lift settings under low RPM engine operations are very different from those under high RPM. Optimal low RPM valve timing and lift settings would result in insufficient fuel and air at high RPMs, thus greatly limiting engine power output. Conversely, optimal high RPM valve timing and lift settings would result in very rough low RPM operation and difficult idling. The ideal engine would have fully variable valve timing and lift, in which the valves would always open at exactly the right point and lift high enough for the engine speed in use.

In practice, such a perfectly adjustable timing and lift system is complex and expensive to implement and is therefore found only in costly experimental and limited production engines. The vast majority of modern automobile engines operate with a fixed camshaft profile that represents a compromise between low RPM smoothness and high RPM power output. And since the average automobile engine spend most of its time running in the low RPM region, there is typically more emphasis on low RPM smoothness at the expense of high RPM output. Performance-tuned engines have cam profiles that are optimised more towards high RPM operation, where the greatest power can be obtained, but this means that low speed operation is compromised. Anyone who has heard a racing car or a highly-tuned hot rod sitting at idle will note that the engine sounds like it is barely capable of running at that speed.


DOHC VTEC
Honda's VTEC system is a simple and fairly elegant method of endowing the engine with multiple camshaft profiles optimized for low and high RPM operations. Instead of only one cam lobe actuating each valve, there are two - one optimised for low RPM smoothness and one to maximize high RPM power output. Switching between the two cam lobes is controlled by the engine's management computer. 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 VTEC system was originally introduced as a DOHC system in the 1989 Honda Integra sold in Japan, which used a 160HP 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 V6. The DOHC VTEC system has high and low RPM cam lobe profiles on both the intake and exhaust valve camshafts. This resulted in the most power gain at high RPMs and DOHC VTEC engines were thus used in the highest performance Honda automobiles. In contrast to the SOHC implementation which switches between cam profiles seamlessly, when the DOHC version switches cams there is a definite change in the engine note.


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 while the exhaust valves are still actuated by a single cam profile.


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 mixture's swirl in the cylinder and thus allowing a very lean mixture to be used. As the engine's speed increases, both valves are needed to supply sufficient mixture, and thus a sliding pin as in the regular VTEC is used to connect both valves together and start the second one moving too.

In North American markets, VTEC-E can be found in Honda's most fuel efficient cars, including the 1992-1995 Civic VX and 1996-2000 Civic HX.


3-Stage VTEC
Honda also introduced a 3-stage VTEC system in select markets, which combines the features of both DOHC 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
As successful as the VTEC system has been, one of the key arguments against it in comparison to competing systems is that it had only two profiles for timing and lift. i-VTEC answers the critics by introducing continuously variable timing. The valve lift is still a 2-stage setup as before, but the camshaft is now rotated via hydraulic control to advance or retard valve timing. The effect is further optimization of torque output, especially at low RPMs.


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 rpms 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.


References
Honda Motor Co., Ltd. (2004). Technology Close-up (http://world.honda.com/motorcycle-technology/vtec/). Retrieved Sep. 16, 2004.


Driving with VTEC
The original VTEC technology did not do all that much to improve engine power or efficiency at low speeds, though it did mean that Honda did not need to consider high-speed operation at all for its low-speed cam profile. Thus, this has led some to accuse VTEC of being more hype than actual improvement for the average driver. The counter-argument is that with VTEC the higher-speed power is there if the driver needs it. Unlike a higher displacement or force induced engine of similar power output, VTEC allows a smaller and more efficient engine. The ability of the VTEC engines to develop higher RPMs, however, allowed Honda to deliver them with transmissions having lower gearing, which served to increase the acceleration.

Having VTEC does mean that the engine needs to be run at high RPMs to develop maximum power. This requires the constant attention of the driver to keep the power in the optimal RPM band for high-speed driving. Some feel this is an interesting driving challenge, while others find it bothersome

 

[ALBundy]

Originally posted by wann77@Aug 3 2005, 08:59 AM
Is VANOS functions just like VTEC for japs HONDA? :unsure:

Vanos and VTEC are two entirely different systems. To put it in layman's term vanos actually varies the cam timing to optimise engine output, in most cases the timing were advance to produce the "vanos" rush! In single vanos engines, only the inlet cam timing is "variable" and later with double vanos, both inlet and exhaust cams' timing are "variable".

With the "original" VTEC system, the lift and duration of the cam profile is variable through a simple but yet effective solution. At a pre-set rpm (3500?), the cam profiles are changed resulting with higher lift and longer duration, allowing more fuel and air to be sucked into the combustion chamber and hence more power produced by the engine! This certainly made the VTEC engines a favourite with boy racers especially with the wonderful roar under the hood at high engine rpms.

The cam in Calvin Tan's e30 is a good example, great power in the upper range but idling sucks and the engine rocks like a washing machine (similar to the yellow submarine)

With VTEC-i, I supposed Honda has combined the two systems together, 1) continuous variable cam timing 2) variable cam profiling - lift and duration. And that should be superior compared to other systems such as Vanos, Mivec and VVT-i. That being said, BMW has upped the ante with valvetronic, which has variable air intake!

 

[fabianyee]

IMO, i-VTEC system is more superior to the VANOS system and it has been so far reliable. the VTEC system is like having 2 separate camshafts in 1 engine, with a distinct change of tone after the crossover point.

As for the valvetronic, time will tell how reliable it is...

But perhaps the ultimate is pneumatic individual valve actuation... basically doing away with camshafts and opening and closing of valves will be by using individual actuators....

 

[Zoggee]

2 questions...

1.How does a Vtec performs on a Autobox..???


2.How does single and double vanos helps with a manual box..??

 

[amizana]

Very educational forum......keep it up guys.

For my future reference, i even copy and paste
it into Words and save it to the file......... k:

Thanks for your time MRHARTGE, ALBUNDY and
the rest who contributed their knowledge to the members... :getyourfactsright:


I think for the next annual dinner, we can vote for
the best forum initiator..... :yes: :yes:

 

[ALBundy]

Originally posted by fabianyee@Aug 3 2005, 04:22 PM
IMO, i-VTEC system is more superior to the VANOS system and it has been so far reliable. the VTEC system is like having 2 separate camshafts in 1 engine, with a distinct change of tone after the crossover point.

As for the valvetronic, time will tell how reliable it is...

But perhaps the ultimate is pneumatic individual valve actuation... basically doing away with camshafts and opening and closing of valves will be by using individual actuators....

That is what F1 engines been using....otherwise there is no way a 4 stroke engine can rev up to 20,000 rpm. That being said, the engine wont last more than 2000km?? :nyehehe:

 

[ALBundy]

Originally posted by Zoggee@Aug 3 2005, 07:26 PM
2 questions...

1.How does a Vtec performs on a Autobox..???


2.How does single and double vanos helps with a manual box..??

Wah Zapple pretending lor....

If I have a manual box, I don't need VANOS...I NEED VTEC!! (isnt this what you wanna hear) :nyehehe:

 

[iCe]

aiyahh,me drive v-tec before oso dun know how it function.all i know the engine sounds change to lebih memekak when reach 4.8 X 1000 RPM (very syiook woo) :nyehehe:

u guys very knowledgeble eh.

informative article by the way. :yes:

 

[E34EuroTouring]

More than a month later. Here goes:

Old Vtec is purely mechanical with no ECU/DME control. Vanos uses electrical solenoid actuation with DME control. So it is more sophisticated.

The was some discuss in the US boards that earlier Double VANOS for non-M engines are not continously variable, it does have 2 cam lobes just like Vtec but actuated a lot more accurately. The nett effect is same for most people, can you feel it ?. More so for some and almost nil for most.
The M3 Double-Vanos is truely continously variable. It screams like a chain-saw from 6000 rpm onwards!.

I can say my Single Vanos M50TU has one cam change at 2800rpm that I felt before when going uphill on 3rd gear. If there is another cam change any higher than 4500 rpm, I never felt it becuase from 4000 rpm to redline is very quick in the M50 engine. Besides the engine screams and I am concentrating on the perfect shift point to feel minor nudges of the car. I would say going uphill (a long and fairly steep uphill) would be easier to feel the second cam change.

In the Honda Intregra Type-R, the 3 cam changes are so distinct even a co-driver can feel it on a flat road or on a track. IMO, this is the VTEC that really works. The normal VTEC 3 or non-Type R engine, one can hardly tell.
On my old SOHC Accord 2.3 manual I felt the 4200 rpm cam change only. It is the sweet spot towards the red line. Alas, it takes forever to get to 4000 rpm due to Honda's long gearing and the weight of the Accord. Worse thing, the Accord consumes TWICE the gas if one drives within that power band compared to normal drive.

 

[portse7en]

anyone needs panadol? :unsure: