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Pintle-Regulated Venturi Induction Prototype Car Delivers 48.1 MPG in EPA Certified Highway Testing

Prv
The pintle-regulated venturi concept. Click to enlarge.

Independent testing of PRV Performance’s Pintle-Regulated Venturi Induction prototype car (a Honda Civic, earlier post) delivered 48.1 mpg in the EPA highway test. Carbon dioxide emissions were 106 g/km. Testing was performed at Environmental Testing Corporation in Aurora, Colorado.

The company has worked through eight generations of prototype, installed and tested in a Honda Civic with a JDM D15B single overhead cam engine. (The JDM D15B was a 1.5-liter SOHC engine applied in the MY 1992-1995 Civics.) EPA fuel economy ratings for the 1995 1.5-liter Civic ranged from 33-41 mpg. EPA highway fuel economy rating for a current, conventional 1.8L 2008 Honda Civic with five-speed automatic is 36 mpg.

PRV induction, with fuel injection directly at a variable Venturi throat, effectively mixes fuel and air due to the high velocity and reduced pressure at the vapor-liquid contact region. Pressure is recovered in the expansion section of the Venturi, thereby reducing engine pumping losses. Fuel vaporization and homogeneous mixing with air improves the burn rate in the cylinder, delivering more complete combustion early in the ignition cycle to improve fuel efficiency.

Road tests of a Honda Civic revamped with a pintle-regulated Venturi fuel induction system demonstrate a 25% increase in highway fuel economy, a 14% increase in city fuel economy and a 15% increase in torque across the entire rpm range, according to the company.

The company will present a paper on the PRV system and the test results at the SAE World Congress in 2008.

Comments

clett

No way do I believe a 15% increase in torque from a simple change of air/fuel mixing!

andy

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

Matt

This increase in torque were measured on our Dyno Dynamics Dyno, the gains are real, i saw it with my own eyes and measured it with my own machine.

Sid Hoffman

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.

gary

A clever idea that I hope catches on, however Detroit is famous for it's "Not Invented Here Syndrome".

clett

"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.

AES

IF it works as effectively as described, and IF it can be verified to work with other engines, then what's the best way to market?

Retrofit kit for existing engines?
Licensing to OEMs?

AES

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

yesplease

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?

Licensing costs. We didn't see VVT-anything until the patents went public domain or however ya describe it.

Toto

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?

Patrick

patents expire...typically I believe it is 20 years.

I'd love to get this as a retrofit kit for my car.

Matt with the dyno & performance shop: Did you hear them discussing aftermarket kits for a variety of engines and what was involved in getting the system installed? I'd imagine a custom intake manifold would make this cost prohibitive for them to do for any but the most common vehicles and then they'd have to make concessions for the rat's nest of vacuum tubing and wiring common on intake manifolds.

GreenPlease

@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?

Treehugger

The improvement in efficiency sounds really good, but I am still skeptical that you can get such an improvement only by a better vaporisation of the gazoline. Also the knocking effect should be worse and not better since a more vaporized fuel will self-ignite more easily than a poorly vaporized one unless you run leaner. Maybe the combustion is really faster and then you can delay the spark after the top dead center. Shorter combustion means less thermal losses and better efficiency. If their claim are true they should be easily confirmed by other manufacturers.

Roger Pham

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.

rca

Toyota, Honda and Nissan have all introduced 4 cylinder engines with variable valve lift(VVL) this year although the Toyota nd Honda engines are not yet available in the USA. I have heard nothing official about GM, Ford or Chrysler introducing VVL anytime soon although I am sure it is under consideration. VVL is in competition with the air impulse valve (Mahle) and the pintle regulated venturi. All three are intended to reduce throttling losses and improve cylinder fill although it appears that the air impulse valve and pintle regulated venturi are somewhat more effective.
We should hear from all the major manufacturers within the next year or so as to which is their preferred method.

Stan Peterson

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)

Stan Peterson

@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

Stan Peterson

@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

Patrick

Stan,

Read his comment again: VVL variable valve LIFT not timing. Be slower to attack and quicker to comprehend next time.

rca

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!

Paul

Yes, there has been a bit of misleading products promising better fuel mileage or "magic" carburetors, as RCA posted. However, for people not familiar with the potential still available by mixing the fuel better or preheating it, research Hank "Smokey" Yunick and his hot vapor cycle adaibatic engine. I was first interested in it in 1985, when Smokey was getting decent press coverage for his work and showing off a 250hp 50mpg American Pontiac Fiero. He was showcasing his stage 1 system, and he already had stage 3 in development. However, his patent was purchased by a large company and for one reason or another, the system never made it to market. So, while I cannot say the pintle system works, it's not fair to say it does not. Anyone willing to pursue increased efficiency, emissions, and performance, should be commended and supported.

Paul

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

Andrey

Gasoline direct injection engines do not need variable valve lift and throttling. Aggressive valve timing will do just fine. GDI supports charge stratification (even in overall stoichiometric mode), which allows increasing of effective compression ratio without risk of charge detonation. GDI throttles engine is true variable CR/Atkinson/Miller cycle engine, having high partial load efficiency, high low-end torque, and high max power. It is the best gasoline engine layout to fit turbo for high-performance operation. GDI engines already have 5 years reliable operation history on the roads, and do not have problems to meet most stringent emission standards. When adsorbtion NOx cats technology will mature, lean burning GDI engines will make light duty passenger car diesels obsolete.

Inventing new carburettors or other advanced throttling/mixing devices is an attempt to improve yesterday and already obsolete technology.

James

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, jmeyer@prvperformance.com

Matthew Marrone

@Patrick

Yes, aftermarket performance was discussed with James from PRV. He gave us a generous offer to develop the performance side of his invention. Unfortunately, we are too new of a business (1 year old) to take on research like this. We have to pay the bills to keep the lights on. We may come back to it (if the aftermarket performance side of this is still available) when we're more profitable and can spend valuable man hours developing the performance side of this.

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