I drove both the Odyssey and the Pilot today with the VCM. I could NOT detect the change over. Only when flooring it while in 3 cyl. mode did it instantly go into 6 and then the AT downshifted. I hate AT's, but there it is.
New Honda Pilot VCM engine
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If Honda pulls this off it'a an amazing feat. A V6 is a shaker by design and needs a lot of help to run smooth. A three cylinder has got to be a shaker, too. Since the best reason to have a V6 is packaging you've got to be impressed with what Honda is doing.
I need to eat my words...well maybe.
The Pilot I drove was 4WD. According to the brochure only the 2WD Pilot comes with VCM. But the sales weenie said it had VCM. I didn't study the sticker that closely to see if it had the i-VTEC.
For sure the Odyssey had the i-VTEC (VCM) it was fully loaded. Now this is the interesting thing - it does appear the ACM and ANC work along with the VCM.
That said - will probably get the EX model that doesn't have VCM for cost reasons. I say it's one less system to malfunction.
The Pilot I drove was 4WD. According to the brochure only the 2WD Pilot comes with VCM. But the sales weenie said it had VCM. I didn't study the sticker that closely to see if it had the i-VTEC.
For sure the Odyssey had the i-VTEC (VCM) it was fully loaded. Now this is the interesting thing - it does appear the ACM and ANC work along with the VCM.
That said - will probably get the EX model that doesn't have VCM for cost reasons. I say it's one less system to malfunction.
You guys are terrible. After all this I went tot he dealer and just drove one. The light on the dash may not be directly connected to the cylinder controls. I could not fell the changeover. There was a problem though. When in 3-cylinder mode it hurt my head. It was like a drumming feeling in my ears. When you stepped on the gas it went away, let up and it came back. We drove another and got the same thing. No one else was bothered, it must be just me.
LarryL - Pilot or Oddy?
I know what was bugging you, I'll bet, - the ANC!
I know what was bugging you, I'll bet, - the ANC!
I was wondering if the noise canceling system would bug anyone. It only comes in the VCM vehicles and is yet another pretty thing to break.
Can someone please explain to me why it is better to have both intake and exhaust valves closed. I don't understand why that would be better with pumping losses from the compression. And how could it run smooth like that? Pull a plug wire (or 3) on your car and try driving it. I really want to understand how this works.
If they could engineer it to do that, why couldn't they design it to hang open the exhaust valves.
I really haven't looked into this much, but I noticed more and more vehicles are coming out with this technology. IMO I wouldn't keep it past the warranty, not yet anyways.
If they could engineer it to do that, why couldn't they design it to hang open the exhaust valves.
I really haven't looked into this much, but I noticed more and more vehicles are coming out with this technology. IMO I wouldn't keep it past the warranty, not yet anyways.
V-6s are shakers because they are a pair of threes cast into one. Absent use of an exotic, impractical-for-production crankshaft, there is no way to eliminate the longitudinal shaking that an inline three will generate, and a V-6, again, is simply two of these, side-by-side. I read an article about this engine, and recall that Honda deemed it necessary to use special engine mounts and active noise cancellation (ANC), via the stereo speakers, to make the NVH in 3-cyl mode acceptable. The ANC, I understand, is active even when you think the sound system is "off". It would be interesting to test drive one with the fuse for the sound system pulled.
Honda does not "blow it" very often (although original trans in the second generation Ody comes rapidly to mind...), so I'm inclined to think that they sorted the VCM system out very carefully before putting it on the market. Time will tell.
"Can someone please explain to me why it is better to have both intake and exhaust valves closed. I don't understand why that would be better with pumping losses from the compression. And how could it run smooth like that? Pull a plug wire (or 3) on your car and try driving it. I really want to understand how this works."
I can speak for the GM DoD system only because that's the only one I'm technically educated on. I can't explain why having both valves closed is a better idea than "Company X" But I can explain in more detail how the GM system works to defeat pumping losses and prevent oil from entering the CC past the rings and settling on the piston face.
DoD becomes active. The first DoD equipped cylinder is approaching the end of its intake stroke.
1) The intake valve closes and the lifter is 'unlocked' allowing the intake valve to stay closed.
2) Compression and combustion occour as normal.
3) The exhaust valve opens and the piston begins the exhaust stroke. As this piston reaches the deck the exhaust lifter is 'unlocked' and the exhaust valve closes before full expultion of the exhaust gasses can occour.
Appearently when the exhaust valve closes and the piston is at Bottom-Dead-Center there is 1 psi of pressure in the cylinder to prevent oil from creeping up past the rings. The crankcase is actually in a constant vacuum to remove evaporitive emissions from oil and raw fuel, so the pressure in the cylinder prevents oil from creeping up the cylinder walls.
The only thing I can see as a breaking point for this setup is the lifter itself. There are two locking tabs in each DoD lifter which lock the lifter in a 'telescoped' position. Those two tabs will be the systems weak-point, hands down. However I suppose there isn't much more you can cost-effectively do to an engine within the required space.
Edit: To prevent the DoD cylinders from becoming too cool, the engine control module will re-start the in-active four cylinders after five minutes of continuous "off-time" long enough to ensure that all engine components maintain operating temperature consistently.
I can speak for the GM DoD system only because that's the only one I'm technically educated on. I can't explain why having both valves closed is a better idea than "Company X" But I can explain in more detail how the GM system works to defeat pumping losses and prevent oil from entering the CC past the rings and settling on the piston face.
DoD becomes active. The first DoD equipped cylinder is approaching the end of its intake stroke.
1) The intake valve closes and the lifter is 'unlocked' allowing the intake valve to stay closed.
2) Compression and combustion occour as normal.
3) The exhaust valve opens and the piston begins the exhaust stroke. As this piston reaches the deck the exhaust lifter is 'unlocked' and the exhaust valve closes before full expultion of the exhaust gasses can occour.
Appearently when the exhaust valve closes and the piston is at Bottom-Dead-Center there is 1 psi of pressure in the cylinder to prevent oil from creeping up past the rings. The crankcase is actually in a constant vacuum to remove evaporitive emissions from oil and raw fuel, so the pressure in the cylinder prevents oil from creeping up the cylinder walls.
The only thing I can see as a breaking point for this setup is the lifter itself. There are two locking tabs in each DoD lifter which lock the lifter in a 'telescoped' position. Those two tabs will be the systems weak-point, hands down. However I suppose there isn't much more you can cost-effectively do to an engine within the required space.
Edit: To prevent the DoD cylinders from becoming too cool, the engine control module will re-start the in-active four cylinders after five minutes of continuous "off-time" long enough to ensure that all engine components maintain operating temperature consistently.
What's going to happen to these complex systems when the warranty runs out? The ABS light on my car would not go out one day and it cost me $500 in parts to fix it in my driveway. Every year these cars get more and more stuff. If you want better mileage, you could just buy a vehicle that gets better mileage without all the tricks. The first time this VCM takes a dump, outside of warranty, you're screwed. Honda already charges an arm and a leg for parts. As Hondas get older, the price of Honda parts that you can only get from the dealers, keeps going up and up. I'll bet that anything to do with this system is expensive. Simple might be better.
Pumping losses are frictional losses such as when as a fluid moves through an opening. A piston acting on a closed cylinder can adiabatically compress the remaining, now trapped exhaust charge. Adiabatic is a thermodynamics term: whenever you hear it you are supposed to think 'reversible, no energy lost.'
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