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http://www.cleanmpg.com/photos/data/2/Japanese_Flag_30x22.jpg World-class dynamic performance along with approximately 13 percent* improvement in fuel economy. (cleanmpg.com/forums/showthread.php?t=2343)

http://www.cleanmpg.com/photos/data/501/Honda_-_A-VTEC_Engine.jpgWayne Gerdes - CleanMPG (cleanmpg.com) - Sept. 25, 2006

Next gen A-VTEC - 2.4L in a non-hybrid Accord - 27/38 highway.

Honda has further advanced its VTEC (Variable Valve Timing and Lift Electronic Control System) technology with the development of the Advanced VTEC engine, which achieves high performance along with outstanding fuel economy and lower emissions. The new engine combines continuously variable valve lift and timing control with the continuously variable phase control of VTC (Variable Timing Control). Honda plans to release a production vehicle equipped with the new engine within three years.

This new system permits optimum control over intake valve lift and phase in response to driving conditions, achieving improved charging efficiency for a significant increase in torque at all engine speeds. Under low to medium load levels, the valves are set for low lift and early closure to reduce pumping losses and improve fuel economy.

In combination with optimized intake components, these advances in control technology result in world-class dynamic performance along with approximately 13 percent* improvement in fuel economy. The new engine is also exceptionally clean, with exhaust emissions that meet both U.S. Environmental Protection Agency LEV2-ULEV regulations and Japanese Ministry of Land, Infrastructure and Transport requirements for Low-Emission Vehicles, with emission levels 75 percent lower than those required by the 2005 standards (based on Honda calculations).

* Engine only, as compared to production 2.4-liter i-VTEC engine (Honda calculations).

Anyone thinking:

164mpg + 13% = 185mpg? :D

Only if the Insight lives long enough to see a 2nd generation.:(

Just dreaming....

Hi All:

___It is now the three year anniversary of the A-VTEC announcement and from all I can tell, we have little to nothing to show for it :( Honda has improved the HP and Torque ratings of the 2.4L as seen in the CRV and Accord but FE has not really increased with a fall-off in some cases. We have some news about the 2010 CRV but A-VTEC seems to have been forgotten at Honda for some reason?

___Good Luck

___Wayne

Hi All:

___It is now the three year anniversary of the A-VTEC announcement and from all I can tell, we have little to nothing to show for it :( Honda has improved the HP and Torque ratings of the 2.4L as seen in the CRV and Accord but FE has not really increased with a fall-off in some cases. We have some news about the 2010 CRV but A-VTEC seems to have been forgotten at Honda for some reason?

___Good Luck

___Wayne


More of Honda resting on there rump and doing the GM thing.

So sad! :(

<snip>Honda has further advanced its VTEC (Variable Valve Timing and Lift Electronic Control System) technology with the development of the Advanced VTEC engine, which achieves high performance along with outstanding fuel economy and lower emissions. The new engine combines continuously variable valve lift and timing control with the continuously variable phase control of VTC (Variable Timing Control). <snip>

I'm a little lost. Our HCHII has VTEC, and I read through the Service Manual a bit on that, but not in depth, ie: I didn't fully comprehend it ;)

Looking through the above, there are 2 bracketted phrases, that I think summarize the difference between VTEC and A-VTEC. Both seem to have variable valve lift and timing. The second using the expression "continuously variable phase control", but the second bracketted description doesn't seem that different than the first.

My mind is starting to lock-up, can't see the difference. Is there some improvement in the valve timing, more control to the timing.

I'm a little lost. Our HCHII has VTEC, and I read through the Service Manual a bit on that, but not in depth, ie: I didn't fully comprehend it ;)

My mind is starting to lock-up, can't see the difference. Is there some improvement in the valve timing, more control to the timing.

In short:

Honda has been using various VTEC iterations for years.

VTEC (earliest)- A dual-cam setup with a cam for regular driving and a "wild cam" for performance. The engine automatically changes cams at ~5000rpm.

VTEC-e (1995~2005) - same as VTEC except normal cam is ground for FE and "wild cam" is a normal profile cam that comes online ~2300rpm.

i-VTEC (~2006 - Current) - 3 stage version combining VTEC and VTEC-e. Cam profiles for FE, normal, and performance driving. Limited changes of the intake valve timing within a cam profile.

A-VTEC (R&D 2006-current) - ultimate VTEC. Continously adjusted cam profile for max FE and performance. NOT IN PRODUCTION.

Mendel

Honda has two major types of vtec. The economy version and the hp version. And within those two classes there are variables.

What many were hoping for by now from Honda was a new mix of economy and high output that Honda is more than capable of doing. While the current 2.4l K is the over all work horse for Honda. Many where hoping to see the 2.0 K like whats found in the Si to become the new force to be reckoned with. Maybe a 1.8L DOHC R-18. The SOHC engine like whats in our HCHII does not have much leg left in it to be upgraded. Also in this group is the 1.5l I4 and the SHOC V6. The reason being only one cam. The DOHC engines are the ones that will give up more advancement in ICE management. You can only get so many cam lobs on a single cam. You can only advance and retard one cam so much when the intake and exhaust valves live on one cam. Thus the DHOC engines offer much more tuning ability.

Honda as the ability to make to 2.0 and 2.4L I4's new world leaders in mpg and high output. But don't seem interested in it. We can only hope Honda is laying the ground work for this move to take place with there advancements in casting as seen in the R-18 found in the standard Civic, lighter and stronger piston rods with cracked caps also found in the R-18. ( Lighter, stronger rods with cracked caps is standard tech in aircraft engines. ) These two new technology and resulting production methods will be a must have for any real gain. The head, block and lower block castings will be much more complex. As will the inner workings of the engine. From the crank and rods, to the pistons and head layout. Another advancement will be the timing chain. I myself have no idea why it has taken Honda so long to go to a timing chain in there car engines.

It would seem Honda has slowed way down on there ICE development and focused more on building junk transmissions. It would seem Honda can build a good 5 MT and AT for I4 powered cars. But don't have a clue when it comes to a 6MT be it I4 or V6 or a AT. And the CVT is a rib cracking joke of a tranny. I firmly believe Honda can make a diesel that can meet or exceed the EPA's request. They just can't build a automatic transmission that will hold the oil burner's nor the North Americans interest. I'm sure the oil burners would shred any or near future AT tranny lazy ass North American driver's would demand.

It would seem the days of early fast pace development are gone now in the Honda engineering dept's. The CVCC and lean burn look old don't you think. Nothing but vtec since. And it's old hat now. :(

But they can build one cute robot. :)

Thanks all for the crash course. I guess bottom line is to wring more power out of a smaller displacement engine.

So from Warthog I undertand, the A-VTech has continuously variable valve lift. Whereas the VTEC on our HCHII (for example) has only two lift heights. I think I can actually feel that on occasion. There's one overpass we used to cross on a regular basis, and about 1/3 of the way up the climb side it always felt like the engine "woke up".

How to achieve a variable lift sounds tricky. I'd speculate it involves somehow shifting the center of the cam, or the timing of the rotation. How else to make the height of lift continuously variable?

Our HCHIIs are iVTEC, the changing between profiles is done with two solenoids that change oil pressure and force the cam followers onto another set of cam lobes. There is power, economy, and idle. Power being the "Wild" profile, economy the "Normal" profile, and idle- smooth lobe-less rings that keep the valves tightly shut. HI2 lacks the "Power" profile.

Toyota does their VVTI with oil pressure advancing or retarding the cam timing by a certain amount of degrees in relation to what the crank is up to.

Our HCHIIs are iVTEC, the changing between profiles is done with two solenoids that change oil pressure and force the cam followers onto another set of cam lobes. There is power, economy, and idle. Power being the "Wild" profile, economy the "Normal" profile, and idle- smooth lobe-less rings that keep the valves tightly shut. HI2 lacks the "Power" profile.

Any idea what happens to the valves during Electric Only, or Regen Braking. I always picture the valves are held open at these times, to allow the engine to free wheel.

As Kacey said, the "idle mode " deactivates the valves so they remain closed. I have to admit my brain has a problem with this but it has the effect of eliminating "pumping losses" which are what we think of as "engine braking" in a normal car. This way there is less energy lost when you lift off the gas so more inertia is available for regenerative braking and recharging the battery pack. If you ever top out the battery you will find the brakes require more pressure because you have no regenerative "drag" and no "engine braking" either!

The HCHII motor has a 3 phase VTEC but the Insight has only 2 phases. The missing feature is the high RPM cam mode which explains why the HCH has more top end power.

While Toyota deserves a lot of credit for their Hybrid system, I still have faith in Honda's ability to build exceptional motors which at the end of the day are still the "heart" of a car, even a hybrid!

Cheers,

Roger

Hi Mendel:

___They are shut during Regen/Fuel Cut and Electric only to remove pumping losses. While one cylinder is compressing, another is decompressing with the valves closed.

___Good Luck

___Wayne

Yes as Wayne and Roger said, also during our "Glides" the valves are held shut. I'm not 100% sure but I think you get engine braking back once the pack is filled and the system sees you trying to stop from speed.

From 10.5-7.5 mph the HCHII will idle normally that way brake fade isn't a huge issue, though I'd prefer an auto stop during those speeds personally.

I suspect we won't see true continuously-variable lift *and*
duration and phasing until full electronic direct solenoid control
of valves is a reality. But in the interim they can do some pretty
clever things with oil-pressure-driven actuators. I'd like to
see a return to a single set of lobes and something that lets
them push a valve stem more or less, and then that whole thing
phased by overall timing. Given what I've seen that Toyota did
with the hydraulic lash-adjusters in the new Prius engine, that
"pump up" with oil pressure and automatically give zero valve
clearance [like hydraulic lifters but at the stationary fulcrum
points instead], it seems doable to give something like that a
variable pressure-relief path with external control.
.
_H*