Future engines. Beyond the stretta ?

[Heli_Duc-Tech]

Looking at technological advances elsewhere..

Possible changes...

1. Two channel (one sensor per cyl) Closed Loop wideband o2 feedback. The ECU would automatically retune in real time to match the programmed air fuel ratio. Already can be done using aftermarket engine management systems.

2. 48 tooth clutch. Just contract with STM.

3. knock sensors one per cylinder. Controls ignition advance by listening for knock and adjusting timing as needed. Can be accomplished with aftermarket engine management systems (Motec etc)... Can also be done with a J&S safeguard (piggy back Black box). BMW has used them on cycles with good gains in power. You dont need to engineer in as big of a "whoops" zone when it comes to compression ratio and ignition timing.

4. Get the F1 brainiac who came up with the stretta head to out do himself via adding in full roller rocker arms. Roller at cams, fulcrum, and valve. Maybe even HLA's (Hydraulic Lash Adjusters) on the head side of the fulcrum.

5. Go GDI. Gasoline Direct Injection. Hit up google.. Better fuel economy and performance. Alot better.

6. Swap the single shared timing belt gear for a one with hyraulic timing phaser. All 4 cams can then be advanced and retarded by the ECU for variable valve timing.. Just like GM did to some of its engines as of late.

Call it the Testaperfetta?

[Jake99x]

i just want a bike that can fly.

[OldBaldy]

Fully electronic control of valve system (thus negating the need for throttle plates in the intake, much like the BMW car system, but with full electronic control of the valve timing, open and close rate, and lift), fully electronic control of intake system (variable tuned lengths), fully electronic control of exhaust tuned length, full-time wide-band closed-loop air-fuel mixture control, with knock sensor retard - or perhaps even fuel and spark timing auto-optimization based on built-in torque-sensing engine mounts, electrically controlled liquid cooling pump, etc.

This would boost MEP substantially, despite the limited rev capability of the V-twin, and push power up above any sensible street level for current tire technology.

The main "issue" will end up being - how much of this the rider will be allowed to manipulate, in order to reset the compromises to a specific result - i.e. more power for more noise/less economy/more pollution, etc. My guess is this potential adjustability will be minimized or removed in stock form, to prevent ANY tuning of these critical systems by the rider - thus making a change in expensive EMS/ECU almost mandatory despite all the good stuff that it can provide in stock form.

It will get more and more expensive and complex and difficult to achieve any improvements over stock - the price to pay for such substantial improvements in stock performance.

[Heli_Duc-Tech]

Originally Posted by OldBaldy

Fully electronic control of valve system (thus negating the need for throttle plates in the intake, much like the BMW car system, but with full electronic control of the valve timing, open and close rate, and lift), fully electronic control of intake system (variable tuned lengths), fully electronic control of exhaust tuned length, full-time wide-band closed-loop air-fuel mixture control, with knock sensor retard - or perhaps even fuel and spark timing auto-optimization based on built-in torque-sensing engine mounts, electrically controlled liquid cooling pump, etc.

This would boost MEP substantially, despite the limited rev capability of the V-twin, and push power up above any sensible street level for current tire technology.

The main "issue" will end up being - how much of this the rider will be allowed to manipulate, in order to reset the compromises to a specific result - i.e. more power for more noise/less economy/more pollution, etc. My guess is this potential adjustability will be minimized or removed in stock form, to prevent ANY tuning of these critical systems by the rider - thus making a change in expensive EMS/ECU almost mandatory despite all the good stuff that it can provide in stock form.

It will get more and more expensive and complex and difficult to achieve any improvements over stock - the price to pay for such substantial improvements in stock performance.

The expensive and complex part is what I was trying to avoid...

Changing the one belt sprocket out is the most effective way to add VVT. A bolt on could probably be engineered for the current engines... Being able to advance and retard the cams to match the current RPM is good for consideral gains at the least expense.

Closed loop WB is something the ECU MFG for Ducati alread knows how to do and there are two bungs in my stock system.

The GDI and the full roller rockers are the biggest changes... Everything else I brought up could readilly implemented.

[bevel450]

Not exactly sure what roller rockers/tappets are going to buy you. They've been messed with in every racing series that uses rockers, and have been discarded, and re-discovered, and discarded....you get the picture....for half a century or more.

Two questions worth asking: what specific advantage would if offer, and does the Desmosedici in either MotoGP or forthcoming street bike have them ?

Originally Posted by Heli_Duc-Tech

The expensive and complex part is what I was trying to avoid...

Changing the one belt sprocket out is the most effective way to add VVT. A bolt on could probably be engineered for the current engines... Being able to advance and retard the cams to match the current RPM is good for consideral gains at the least expense.

Closed loop WB is something the ECU MFG for Ducati alread knows how to do and there are two bungs in my stock system.

The GDI and the full roller rockers are the biggest changes... Everything else I brought up could readilly implemented.

[Iwannaduc]

If nothing else, a roller rocker with the roller on the cam side would eliminate any flaking rockers. Also, a roller rocker permits a more radical cam profile with steeper ramps. I've not heard of them being employed on a Desmo valve train. It makes sense that it would be at least in the manner I described. The key issue would be how to manufacture them to be small enough and durable enough to fit into the Testastretta head. If that could be overcome, I think it would be a benefit to any Desmo valve train that it could be applied to.....sean

[Heli_Duc-Tech]

Have you seen the rockers on a DOHC four. Such as a Mitsubishi 4G63? They have a roller at the cam contact, a simple radius at the valve and the hydraulic lash adjusters tip forms the ball that is the fulcrum. They are tiny and tolerate extreme RPMs, ramp rates and pressure (high rate valvesprings).

Adding just the roller to the cam end of the existing desmo rocker system would be easy..

If the clearances were left to get too wide.. Say skiping an adjustment by a longshot for example.. All the potential slapping around could beat the inner roller bearings up pretty good.

So it would be possible to wreck them... Its just that they dont need anywhere near as much oil to be happy so the reduced oil at the rockers at start wont effect them.

Much of the wear can likely be attributed to changes in oil formulation and running oils not suited to tappets w/o rollers.


http://www.hotrod.com/techarticles/e...ppet_cam_tech/

Around the time of the flat-tappet lifter shortage, motor oil was experiencing its own changes. Engines with flat-tappet cams have extremely high pressure loading at the contact point between the lifter crown and the cam lobe. According to Mark Ferner, team leader for Quaker State Motor Oil Research and Development, "Even stock passenger cars can see pressure in excess of 200,000 psi at the point of flat-tappet/cam lobe contact." To prevent excess wear, traditional motor oil included a generous dose of antiwear additives, primarily zinc dialkyl dithiophosphate (ZDDP). "The chemistry is such that the additive is a combination of zinc and phosphorous," says Rockett Racing Fuel's Tim Wusz. "Typically the phosphate amounts are about 75 percent of the zinc amounts. For example, if there was 0.100 percent zinc by weight in the motor oil, then the phosphate is about 0.075.

"Ferner adds, "The zinc reacts with the cam lobe's iron surface. That creates a sacrificial chemical coating strong enough to keep parts separated to reduce the wear." Although great for keeping a flat tappet alive, as an engine ages and develops blow-by, some of the additives flow out the exhaust where they can degrade oxygen sensor and catalytic converter performance. Faced with ever more stringent emissions standards and the governmental mandate for extended emissions-control- system warranties, the OEMs got together with the motor oil makers and decided to reduce the amount of ZDDP in street-legal, gasoline-engine motor oils. After all, they weren't needed with modern roller lifters and overhead-cam followers. The reduction first started in the mid-'80s, and it has been a gradual process, but the latest API SM and GF-4 specs have reduced ZDDP content to such an extent that the new oils may not provide adequate protection for older, flat-tappet-equipped vehicles running nonstock, performance cams and valvetrains. And it will only get worse; projected future oil spec revisions will likely reduce ZDDP content even more

[bevel450]

Well, that all sounds good, but I think you haven't answered the question of what is the advantage to them.

What is it ?

P.S. I confess to having used roller cams and roller rockers in several cars. Great kit for impressing the peasants, but hell if I could ever quantify the advantage.

[Iwannaduc]

Are you asking what the performance advantage would be? I couldn't say for certain because I don't have anything to compare to. I would guess, you'd get a more efficient engine, less friction usually equals less heat which usually means better performance. Being able to run steeper ramp angles usually means more lift is possible for more exact durations which should equal more RPM equalling more power. As I said, I don't know of any application of roller rockers/roller cam to a desmodromic valve system so I can't quantify any performance advantage. Just the reduction in friction and no more flaking rockers would be worth it.......sean

[Heli_Duc-Tech]

Originally Posted by bevel450

Well, that all sounds good, but I think you haven't answered the question of what is the advantage to them.

What is it ?

P.S. I confess to having used roller cams and roller rockers in several cars. Great kit for impressing the peasants, but hell if I could ever quantify the advantage.

On cars... I'll assume you were talking pushrod v8. The part contacting the cam here is the lifter.

http://www.hotrod.com/techarticles/h.../photo_22.html

Anyway since the rocker on the desmos touches the cam directly and is in fact curved it is not really a flat tappet.

So we are really looking at a closer comparison to roller cam followers..
Look at the little bit of surface area worn on one of the many rocker photos here... Small contact patch huh?

With the roller the entire circumference of the roller wheel is the area making contact. Also since it rolls along the cam this much larger area is distributing a much lower total amount of wear across its much larger area!

Also if you put rollers on the cam and the valve end you have alot more choices in materials to make the arms out of.

IMHO in a production situation I would go with powdered metal forging..

On these crane honda car followers its mostly billet AL... Just not the roller nor the adjustable valve contact.

http://www.cranecams.com/images/down...All%20PNs).jpg

For a desmo going roller at the valve end is easy for the openers.. Just like any other roller rocker...

For the closers... Two rollers will have to contact the collet on either side. Here I would go with a nice light collet made of Titianium much like comp or crower valve retainers. It would need to be as wide as the rollers that straddle it plus the diameter of the valve stem.

For a idea of what a forged skeletonized roller rocker looks like..

http://www.compcams.com/technical/Ca...07/266-274.pdf

In regards to VVT.. Yes BMW's Vanos is some cool stuff.... Just not simple nor economical..

The hydraulic vane cam phaser is stupid simple by comparison with some great gains despite the simplicity. Put one single phaser on the one sprocket that drives both belts and you can advance and retard every cam in the engine in unison... Convienient..

I have driven one of the GM trucks with the VVT.. Nice fat power band.
On the L92.. Here is a snip...

The vain phaser is actuated by hydraulic pressure from engine oil, and managed by a solenoid that controls oil pressure on the phaser. The phaser uses a wheel or rotor with four vanes (like a propeller) to turn the camshaft relative to the cam sprocket, which turns at a fixed rate via chain from the crankshaft. The solenoid directs oil to pressure points on either side of the four phaser vanes; the vanes, and camshaft, turn in the direction of the oil flow. The more pressure, the more the phaser and camshaft turn. The Vortec 6.2L’s new E38 engine control module (below) directs the phaser to advance or retard cam timing, depending on driving demands. The dual-equal phaser can turn the camshaft over a range of 31 degrees relative to the cam sprocket (or 17 degrees advance, 45 degrees retard relative to the crank).

The benefits are considerable. The cam phaser changes valve timing on the fly, maximizing engine performance for given demands and conditions. At idle, for example, the cam is at the full advanced position. That allows exceptionally smooth idling. Under other operating demands, the phaser adjusts to deliver optimal valve timing for performance, drivability and fuel economy. At high rpm it might retard timing to maximize airflow through the engine and increase horsepower. At low rpm it can advance timing to increase torque. Under a light load (say, casual everyday driving), it can retard timing at all engine speeds to improve fuel economy. Without cam phasing, a cam design must be biased toward one strength or another—high-end horsepower or low-end torque, for example—or profiled at some compromise level that maximizes neither.

Variable valve timing allows linear delivery of torque, with near-peak levels over a broad rpm range, and high specific output (horsepower per liter of displacement) without sacrificing overall engine response, or drivability. It also provides another effective tool for controlling exhaust emissions. Because it manages valve overlap at optimum levels, it eliminates the need for an Exhaust Gas Recirculation (EGR) system