Yep, there are plenty of examples of successful displacement on demand, in use for many years. The new camaro will be fast and get great fuel economy - that car will once again put the hurt on mustang.

 

the valves don't shut. how do the valves close if the cam lobes are still riding on them? the only way they could shut is with a camless system. which would uses electric actuators on each valve.

 

I think the Northstar just has a solenoid that lifts the lifters so that they are no longer riding on the cam.

 

i will stick w/ having all my cylinders firing and wearing down AT THE SAME TIME

 

lol SO you are worried about less carbon build up on the unused cylinders? Its not like the shut down cylinders are wearing faster...

 

Cmon! Both valves are shut on the compression stroke anyways. So all you gots to do is cut the fuel. You could easily alternate which cylinder gets the fuel. Though I dont think it would run very smooth if you did that. The cylinders would be firing anyways without deactivation. So worst case scenario 4 last to long. The other 4 would wear out at the normal rate. I dont see a problem. As long as it is reliable and seamless I would be for it.

 

wat about the rings,bearings,
u got em so why not use em all the time

 

i dont know its just seems pointless to me git a V8 and not use all the cylinders if gas milage is want u want git a dam honda. PLUS i dout ya'll will see a stick shift in these v8-4 bangers for a long time hinse taking the fun out of driving
but hey its just my opinion

 

The point of a displacement on demand engine is to save fuel. So thats why.

Instead of building a DOD they could just build an inline 6 but Im sure marketing analysis told them a v8 that runs on 4 cylinders would sell better.

Not sure Im with you on that. Who wouldnt want a v8 that got good mileage and was potent too. Why not a stick? They are more efficient too.

 

There is no difference in power. If you need it you get it.

Do you really need all 8 of those cylinders pounding away cruising at highway speeds? If you have to pass someone they turn back on faster than you can blink an eye.

If you think this is bad wait until Displacement on Demand Hybrid pickups start hitting the market.

 

Rings = you still have compression in the cylinder, Bearings = they are still getting oil, no biggie.

My friend, you need to embrace this simple technology, unless you like feeding 100 dollar bills into your tank for fun

 

im not gona spend 40 + grand when i can get a sho taurus (which i am) for under 5 grand and get 20+ miles and still have a stick shift thats wat im doin

 

The point of fuel injection is that you have almost no cylinder wear, if any, over the life of the engine as long as you don't do something like ignore check engine lights all the time. That is why a throwaway engine like the Northstar even makes it to 100,000 miles even though it has no meat for an overbore job.

Fuel washing oil off cylinders....a thing of the carbed engine days. Rejoice all!

 

I don't know about the Dodge system but I'm sure it's nearly identical to the GM system (of which I am familiar).

The SAME 4 cylinders get "shut off" each time the MDS or DoD (active fuel management) is enabled. The fuel delivery and ignition system for those cylinders is EASY to do due to the fact that the PCM controls them anyway...simply don't activate the coil for that cylinder or the fuel injector.

The valve train on the other hand is a little more complicated. The lifters for those 4 special cylinders have a lifter inside of a sleeve. The sleeve rides on the camshaft lobe. There is a locking pin inside the assembly that locks the lifter to the sleeve when DoD oil pressure is absent. When the PCM commands DoD, oil pressure is routed to the release channel of the lifter sleeve, thus unlocking the pin inside and allowing the sleeve to move independently of the lifter. A spring inside the sleeve keeps the lifter bottomed to eliminate noise.

Yes, a small amount of cylinder pressure is trapped in the cylinder while DoD is activated but this is only to keep any vacuum from pulling oil past the piston rings and causing plug fouling. This is done by deactivating each cylinder at the very bottom of the compression stroke.

That's about it....

Cody

 

Hmmm, so it sounds like a variation of Honda's VTEC. Interesting, I was wondering how it worked.