From the release by Toyota, it sounds like the throttle butterfly is eliminated:

"While conventional engines control air intake using a throttle valve, Valvematic adjusts the volume of air taken in by continuously controlling the intake valve lift volume and timing of valve opening and closing"

Great minds think alike!

A series hybrid will not need an engine with variable timing.

Rafael: Thanks for the education.

I wish that this technology along with cylinder deactivation could be retrofitted into my '05 Acura RSX.

Hi All,

One has to wonder if a poppet throttle valve would be advantageous. The aerodynamics of the butterfly valve are just horrendous. If one made a tear-dropped shapped poppet, with a sealing surface, one could possibly reduce the turbulence in the intake plumbing dramatically. This might be implemented more cheaply than the engine valve variable opening.

Toyota's approach is doing this, by using the engine poppet valves. So there is no need for a good aerodymic shape - one wants turbulence in the cylinder. They do save the expense of the electrically operated throttle valve.

And lets remember, the engine is still throttled, so there are still pumping losses. Just less pumping losses due to the intake air flow being smooth till it goes into the cylinder. As one might be able to achieve with an aerodymic throttle. Might be a good retrofit project for a manually controlled throttle engine.

Rafael - none of this technology recovers braking energy. And as one that actually drives around the US, I can tell you first hand that "stop, wait, wait, go, and stop again", is a large consumer of gasoline here. 10 % is only 1/8 th the improvement the Prius achieves. We are talking about 3.4 mpg, or 37.4 mpg instead of 34 mpg on a Camry, right !?

donee,
The advantage of variable lift valve is that the valve lift is reduced at low intake flow, thereby maintaining turbulence in the intake air/fuel for proper mixing in order to promote efficient combustion with minimum emission of PM and HC.

Furthermore, if engine intake is done behind a throttle valve, the piston is working against partial atmospheric pressure for the entire intake stroke.

However, if variable timing valve is used without a throttle plate, so as to allow the intake valve to close in the middle of the intake stroke, then the piston is NOT working against partial atmospheric pressure for the initial part of the intake stroke, while the partial vacuum in the remaining of the intake stroke will be cumulative a lot less than the partial vacum behind the entire intake stroke behind a throttle plate. (the integration of the differential of the instantaneous force experienced by the piston multiply by the distance the piston travel for the rest of the intake stroke will be a lot less than the constant partial vacuum experienced by the piston for the entire intake stroke.)
The turbulence behind the throttle plate does not account for a large percentage of pumping loss.

Rafael has a good point in that a full hybrid has the engine running at high manifold pressure (low manifold vacuum) for most at the time, and that the engine is shut off during coasting, thereby pumping loss will be quite low. Furthermore, a full hybrid allows the engine to be used at a more constant power setting, in which the valve lift can be tuned for maximum efficiency, thereby, there will be little to be gained in return for the additional cost and complexity of variable lift mechanism. Transient power demand can be partially met by power of the battery and electric motor.
But, of course, full hybrid is more expensive hence limit large scale adaptation. So, if a simpler and cheaper mechanism that can be more widely adapted in order to reduce fuel consumption, then it would be just as good.

"continuously controls intake valve opening/closing timing"

With the Valvematic system on an Atkinson cycle engine, wouldn't it be variable compression ratio?

This is what Mazda is doing with there 1.3l engine.

http://www.mazda.com.au/articleZone5.aspx?articleZoneID=3817

Andrey,
Good point regarding high exhaust gas temperature on engine running at high throttle setting (high manifold pressure), but Atkinson cycle allows more expansion of exhaust gas, hence will reduce exhaust gas temperature and pressure somewhat, with concomintant reduction in noise and harshness. So, it appears that Atkinson cycle is a must-have for a full-hybrid vehicle, because engine efficiency map reveals that peak efficiency won't be reached til 70-80% of maximum manifold pressure is used. A non-hybrid vehicle in highway cruise will use 1/2 or less of the manifold pressure required for peak efficiency.

GDI would be great if means other than 3-way catalytic converter is used to reduce NOx, because it won't work on lean combustion with excess O2 remaining in the exhaust. Perhaps Honda's scheme for NOx reduction for Diesel engine can be used for GDI, so it would be a quite promising means to raise the efficiency of gasoline engine to par with Diesel engine without some of the disadvanges of Diesel engine. In that way, GDI with Atkinson cycle would be great to complement a full-hybrid drive train.

Angelo,
So far, it appears that ethanol is a deadend, since it takes nearly as much fossil fuel to produce the ethanol.

Serial hybrid direct drive to extender engine with NIMH batteries and a simple turbocharged GDI engine optimized for one speed (high) with no throttle plate, waste gate, variable valve tim. or other nonsense.

Forget trying to get a half percent here or there with the mice on a wheel. Put in absorption air conditioning and or the BMW steam turbine to use othe other 75% of the fuel going out the stack or the radiator! I do know about mass being an inital problem for the first generation.

Rafael:
Please correct me.

Angelo,
The future of ethanol is from cellulosic sources. But, for all the trouble of using expensive enzymes to break the strong cellulose bond, these cellulosic biowaste can be gasified to produce H2 for direct consumption, or H2 and CO product of gasification process can be used to synthesize liquid fuels (methanol, ethanol, and HC)to fuel current vehicular fleet, until H2-capable vehicles will roam the streets.

Joe,
Since I share the same opinion as Rafael in this subject, I would like to equate your idea to the GM Volt serial hybrid using a 16kwh battery, with A123 battery now costing $2000 USD/kwh, making battery cost alone $32,000 USD. Adding yet-to-be-proven motor and controllers and engine, and the price tag may hit $50-60,000 USD. How many of these will be sold?

Whereas for $16-18,000 USD, you can buy a Toyota Camry with VVT-i right now, and soon to be equipped by the millions with Valvamatic variable lift together with VVT-i, with 10% or higher efficiency improvement. This will translate to billions of gallons of gasoline saved. Which car will save more fuel?

Angelo,

You had a very sage statement that bears repeating;

"We should be promoting everything that has the potential to replace a portion of our fossil fuels, in my opinion. Economics will then sort everything out."

Unfortunately, government jacka$$ses of the party that beleives in price controls, will mandate prices for thier politically correct technologies. Thus distorting the selection of the best economic solution.

As an example of this proposition. Look at the the Democrats under Clinton withdrawing the US from international Thermonuclear fusion research in order to spend money studying wind and wave and suntans. It set back Fusion by more than a decade, before the sane ones resurrected ITER from the Dead. The Bush DOE and State Department recreated and EXPANDED the international cooperative effort to include most of the developed and partially developed world. With Korea Japan, China, India and Brazil added to the US EU and Russia, ITER is finally being built.

Inexhaustible clean electricity Fusion plants would make a great combination to provide the motive power for PHEVs and BEVs. We could have had them by the late teens. Now not until the early thirties,at best. Thank You Mr. Clinton for not paying attention, and wasting a decade.