Concours Variable Valve Timing

[sparky3008]

https://www.motorcycledaily.com/01november06_concoursvvt.htm

A good question for all you gear heads!!!

 

[radman]

Wouldn't camless, solenoid operated valves (ala F1) be a hoot? Kaw would kill 'em with that, and have the most tractable, powerful motor in ST history, along with all the emissions control one could ask for. Cheap? No, but they've got room.

 

[twowheelnut]

I heard they've trained squirrels to slip the cam lobes at the approriate time...

 

[yamahlr]

I hear they have experimented with the valve of a pig.... that is one ugly m/c. Soooo glad I own the FJR.

 

[jestal]

Sounds like a cam timing device on the intake cam.

That sort of thing is getting relatively common in automotive engines these days.

The cam timing devices (commonly called cam phasers) operate using engine oil pressure. There is a vane type pump arrangement inside the device so that oil pressure applied to one side of the cavity moves the vanes which are attached to the cam shaft itself so that the cam can move relative to the position of the drive sprocket. This requires a high pressure oil feed to the cam via and anulus in one of the cam bearing caps. The oil flow to the cam is controlled by a solenoid connected to the engine controler. There is a set of mag pickups and a target wheel on the cam so that the PCM has feedback regarding cam position. The PCM has a map of desired cam position (or alternate cam timing) for each speed load point and it meters oil pressure to the phaser and watched the position change via the target wheel feedback.

Typically in the situation like this the intake cam would have a phaser for the maximum effect on performance and low end torque. A separate phaser on the intake and exhaust cam is most desireable but the exhaust cam phaser affects emissions more than performance so most performance oriented engines have the intake phaser only.

Or....depending on the cam drive arrangement one phaser on an intake OR an exhaust cam could modify the effective timing of both the intake and exhaust cams if it is set up that way. Hard to say without pictures and a cutaway of the engine.

There are a myriad of systems on the market that all get lumped into the VVT category...or variable valve timing. There are systems that change timing only, lift only, change from one lobe pattern to a second one, change timing on only one of the cams , etc.... Simply calling a system "VVT" is just marketing.....it really doesn't tell you what the system does.

 

[Toecutter]

The cam timing devices (commonly called cam phasers) operate using engine oil pressure. There is a vane type pump arrangement...

The more you know.... :blink: :clapping:

Hey Jestal, your eminence is needed over at EZBored.

His eminence:

 

[markjenn]

The latest $11K Kia has continously variable valve timing on both camshafts, so I really don't think this will be much of a stretch for Kawasaki.

- Mark

 

[sparky3008]

The cam timing devices (commonly called cam phasers) operate using engine oil pressure. There is a vane type pump arrangement...

The more you know.... :blink: :clapping:

Hey Jestal, your eminence is needed over at EZBored.

His eminence:

TOECUTTER, you seem to have a real Hard on for the Ezboard.

Give it a rest will ya! Jeese

 

[jestal]

Jestal, you seem to have a real Hard on for the Ezboard.Give it a rest will ya! Jeese

Uh....Jestal said absolutely nothing about EZBoard or anything related to it. I could care less and never brought it up. Someone else brought up the subject if you will read the entire thread...... Give them the grief, not me.

Jestal

The latest $11K Kia has continously variable valve timing on both camshafts, so I really don't think this will be much of a stretch for Kawasaki.
- Mark

I'll have to look up some info on the Kia system. On one of the earlier systems they had one cam phaser that moved both cams at the same time. They marketed it as "dual" cam phasing since, technically, both the intake and exhaust cams were moving but in reality it was a "poor mans" setup since the movement of the intake and exhaust cams were synchronous...much like a cam in block engine would act with a cam phaser. Most of the time when cam phasing is mentioned on the intake and exhaust of a DOHC engine it means that the intake and exhaust are controlled separately...which is much more expensive and much more difficult.

You mention a good point, though, because some of the variable cam timing systems are on/off arrangements where the phaser is much more simple and just moves the cam, when directed, to another timing orientation. Basically it moves from one stop to the other..i.e..full advance to full retard or vice versa. The more sophisticated systems can continously move the cam orientation to any desired position within an operating range of 25 or 30 degrees. This requires a much more sophisticated control and feedback system.

 

[snowmonkey]

Jestal, you seem to have a real Hard on for the Ezboard.

Give it a rest will ya! Jeese

It is NOT Jestal that has a problem with EZboard. It's the self-appointed FJRforum recruiter Toecutter that continues to righteously throw rocks at EZboard.

 

[sparky3008]

Jestal, you seem to have a real Hard on for the Ezboard.

Give it a rest will ya! Jeese

It is NOT Jestal that has a problem with EZboard. It's the self-appointed FJRforum recruiter Toecutter that continues to righteously throw rocks at EZboard.

Relax, you guys know I typed the wrong name I meant Toecutter. Seems every link I go to recently hes in it talking about the other board.

Apologies Jestal for thinking of you while meaning to type Toecutter. Brain Fart!!!

 

[Constant Mesh]

You can get some idea about the valve control system by looking at these two photos which show the right and left sides of the Kaw engine.

https://www.randomtime.com/pictures/gtr1400/gtr1400_30.jpg

https://www.randomtime.com/pictures/gtr1400/gtr1400_31.jpg

The first photo shows the right side of the engine. You can clearly see some type of servo on the end of the head assembly just below the head cover. You can see an electrical connector on the servo. This probably has something to do with valve control. Also in this photo you can see that the intake cam has a large diameter device at its right end. Probably some kind of variable rotation device allowing for the variable valve timing. There doesn't appear to be anything unusual near the exhaust camshaft.

Also you can see how far the head extends to the right past the 4th cylinder. A much longer extension than what you'd see with a normal cam chain and sprocket assembly.

Don't know what those diagonal crisscross patterns in the head cover between the camshafts tells us.

Finally you can see where the hot water leaves the rear of the head on its way to the radiator. No hot water pipes coming through the head cover.

Think I read somewhere that this engine uses engine oil pressure somehow to properly tension the cam chain.

On the second photo you can see the throttle cables attaching to the throttle body assembly. You can also see the clutch hydraulic line passing over the end of the head cover. Nothing unusual about the head cover, head assembly on the left side. Probably all the hardware associated with the variable valve system is located at the ride end of the intake camshaft.

 

[Feejer/Weejer man]

What is it the new R1 has. Is it what is being talked about here or?

 

[Constant Mesh]

No, the R1 has a system that changes the length of the air inlet pipes inside the airbox. Each throttle body has an air inlet pipe inside the airbox. At higher rpms the R1's system can switch to shorter air inlet pipes which allows for greater air flow with reduced pressure drops in the inlet air piping.

The R1 also has an electric servo throttle system. When you turn the throttle grip the cables turn a position sensor similar to the throttle position sensor on the FJR. This electrical sensor sends a signal to the computer and the computer sends a signal to the electric throttle servo. Thus the computer can take your throttle input and massage and manipulate it and then operate the throttle valves via the designer's software algorithms.

 

[ionbeam]

From Kawasaki specifications:

Variable Valve Timing

With variable valve timing (a category first), the camshaft timing varies in response to rpm and throttle position. The result is high torque output in the low and medium rpm ranges and awesome high-rpm power at the top end. Combustion efficiency is also improved, contributing to enhanced fuel efficiency.

An ECU-controlled OCV (Oil Control Valve) changes the pressure of oil in the chambers of an actuator located at the end of the intake camshaft. As the pressure changes, oil is fed into or out of the chambers via holes in the camshaft. The changing volume of oil causes the actuator to move, rotating the camshaft, thereby advancing and retarding the valve timing.

The intake timing is retarded at low rpm, reducing the valve overlap for cleaner, more efficient combustion in the low-rpm range.

Camshafts

Special cam profiles are used to suit the variable valve timing. The new cams have less lift than those of the ZZR1400.

Lightweight, highly rigid forged camshafts are used for precise valve timing at high rpm.

No, the R1 has a system that changes the length of the air inlet pipes inside the airbox. Each throttle body has an air inlet pipe inside the airbox. At higher rpms the R1's system can switch to shorter air inlet pipes which allows for greater air flow with reduced pressure drops in the inlet air piping.
The R1 also has an electric servo throttle system. When you turn the throttle grip the cables turn a position sensor similar to the throttle position sensor on the FJR. This electrical sensor sends a signal to the computer and the computer sends a signal to the electric throttle servo. Thus the computer can take your throttle input and massage and manipulate it and then operate the throttle valves via the designer's software algorithms.

Sort of a variant of what Yamaha did with the V-Max. At 6.2k to 6.7k rpm they used a servo to open a butterfly valve between adjacent cylinders essentially joining two intake tracts together. This let the V-Max have small dia throttle bodies for excellent low and mid range power then use two throttle bodies joined by the opened butterfly valve for good top end punch.

 

[charismaticmegafauna]

Yes, the V-Max's "V-Boost" is a variant of the frequently used (in autos) bifurcated induction with vacuum controlled butterflies between primary and secondary induction tracts. All valid technologies (IMO): VVT, variable length induction, V-Boost -- and great alternatives to, "There ain't no substitute for 'cubit-inches'".

In the "Nothing new under the sun" category: is the 1909 Pierce 4-cyl motorcycle (Buffalo NY) that had a special cams on its rider controlled camshaft which the rider slid back and forth with a lever. The taller lobes reduced compression for starting (by pedals) and then the camshaft was slid forward for 'power' -- VVT? :blink: :huh: