The torque gain won't be entirely due to the pintel, but also due to spark advance optimisation allowed by better air fuel mixing that will prevent hot spots which cause knock. Any lean parts of the air fuel mixing would encourage knock, so I'm assuming that they've managed to get a very consistent mixture into the cylinder throughout the intake stroke.

Andy

If technology to improve fuel economy is so easy that a tiny little American hole-in-the-wall company can do it, why don't the automakers in Europe, where they actually care about fuel economy do it? I don't expect anyone selling cars in the US to do it, but in Europe they have a genuine interest in fuel savings, I would think this technology would catch on and be developed by Fiat or Peugeot or someone already.

"The torque gain won't be entirely due to the pintel, but also due to spark advance optimisation allowed by better air fuel mixing that will prevent hot spots which cause knock."

If that's the case, then surely they could increase the compression ratio before getting knocking? This would be a reasonable way to increase thermal efficiency and fuel economy but there is no mention they tried it.

Also, does this design necessitate any changes to the engine computer?

One can wonder what happens if the mixture cavitates:
- on one hand, could destroy the venturi fairly fast if not handled properly
- on the other hand, fuel bubbles would turn to nano-scales, greatly enhancing the surface/volume ratio
Anyone has a clue?

@clett

Torque is largely a result of the fluid dynamics of an engine, no? Pintles allow for WOT under nearly all operating circumstances, much like BMW's VANOS variable valve timing. If I recall, the VANOS system resulted in a ~12% increase in torque.

@Toto

This brings an idea to mind. One of the advantages of HCCI is that it allows for a "cooler" burn (and a more complete burn) therefore increasing efficiency. An amateur (me) deduction is that the homogeneous nature of the charge increases the flame front/fuel to air surface area. Perhaps as a substitute to HCCI, multiple small charges could be introduced into the combustion chamber and then spark ignited. Having more than one charge would increase the aspect ratio of the charge relative to the air in the rest of the combustion chamber, allowing the burn from each charge to give up more heat to the surrounding air (read: more complete combustion).

Ultimately, the gross charge inside the cylinder could be homogeneous, though individual charges would be rich. Perhaps this would allow most of the fuel economy benefits of HCCI without the control issues (variable compression ratio and I'd assume very demanding timings).

Care to chime in Rafael?

Just throwing it out there:

Supposedly the advantages of the pintle system is that it allows for fuel vaporization similar to what is achievable with DI while using a port injector and that it allows the throttle to remain wide open without true VVT, all at minimal additional cost. Perhaps the pintle system would be ideal for a low displacement/cost genset in a PHEV?

Greenplease,
You're asking the right questions, but in an advanced pintle cannot duplicate the advantages of HCCI: very rapid combustion due to spontaneous combustion, not requiring a traveling flame-front combustion, as when the homogenous mixture is ignited by a spark, which tends to be slower, and even slower at part load when the charge density is low. Furthermore, the use of hot EGR necessary for compression-ignition at lower compression ratio reduces the pumping loss in the HCCI mode at part load. A slower combustion that does not complete until the piston has moved away from TDC will result in lower peak pressure and reduced effective expansion ratio, hence lower BMEP, and lower efficiency, due to less extraction of energy from the combusted gas.

Treehugger,
You're on the right track. Normal gasoline engine requires significant degree of spark advance before TDC at lower load and at high engine speed. Spark advance triggers ignition which produces more pressure against the piston before TDC which increases the work input into the piston before the power stroke, hence reducing the net work output and engine efficiency. If you can ignite a very rapid and short combustion right at TDC and not before, which completes before the piston has move any significant distance away from TDC, you have achieved a true Otto cycle, which can rival the efficiency of a Diesel engine, but at much lower compression ratio of about 11-13 instead of 18-20 in a diesel engine. This is the essence of HCCI.

Ah! the magic-carburetor returns!

How often do you have to be disillusioned to know that its nonsense.

We even have the requisite expositor expressing his anti-Aamerican verbiage; evil Detroit car makers are suppressing the magic carburetor-throttle plate invention.

If any of you conspiricists actually stopped for a second and thought about it, Detroit will spend billions to increase CAFE by few mpg.
This magic carburetor-throttle plate gets almost a 9 mpg improvement. It obviates any effort needed to meet the new CAFÉ law about to be passed.
Yet they won't pay a Royalty?.

Grow Up. TANSTAAFL!

(There are no such things as a Free Lunch)

@rca,

If you haven't heard about VVT from Detroit then you haven't been listening.
Every manufacturer has at least one engine family and probably three that possess not only VVT on intake but VVT on both intake and exhaust.

Why there are at least two V8 OHV engine families that have been modified to provide VVT; and that is a real trick, that I felt couldn't be done. But it was

Thanks Patrick
Stan Peterson
I know all about the VVT in Chrysler engines, I'm driving a Sebring with 2.4 liter world engine with VVT. Chrysler says that it gives a 3% fuel economy improvement but the indications are that VVL should provide an improvement in the 5% range and the air impulse valve and the pintle regulated venturi could be a little better although new technologies frequently do not meet the claims made for them. I have heard unofficialy that GM has decided against VVT in favor of other technologies but my source isn't a good one. There is no need to apologize Stan, maybe you just got up on the wrong side of the bed or possibly you need new glasses!

Sorry RCA. Misread the post. Stan actually posted the "magic" carbuetor

Per Department of Energy Website, http://www.fueleconomy.gov/feg/tech_engine_more.shtml, GDI will improve fuel economy 12%. GM claims 13% for the 2008 CTS. Cost for GDI varies, but one large European Car company executive told me it cost up to $800 per car. PRV has documented a 25% highway -- at virtually no additional cost over a conventional manifold. It becomes a question of best mixture preparation for the buck before the spark ignites the charge...

Write me regarding this paradigm shift. I would like to hear from you!

James Meyer, Principal, PRV Performance, [email protected]