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Pintle-Regulated Venturi Induction System Shows Improved Fuel Economy, Reduced Emissions

14 October 2007

Cutaway rendering of the PRV system. Click to enlarge.

A Colorado company, PRV Performance, has developed a prototype Pintle-Regulated Venturi (PRV) induction system that replaces a conventional intake manifold with a Venturi for each cylinder of the engine; a fuel injector directly feeding into the throat of the Venturi; and a pintle, moving in and out of the Venturi, to throttle the air flow.

Fuel injection at the Venturi throat results in the effective mixture of fuel and air due to the high velocity and reduced pressure at the vapor-liquid contact region; pressure is recovered in the expansion section. Testing by the company has shown an improvement in fuel economy of up to 14% in city cycle and 25% in highway cycle driving.

Dynamometer results. Baseline system in red, PRV system in blue. Click to enlarge.

Dynamometer testing also indicates an increase in torque and horsepower, compared to a conventional manifold baseline system. Use of the PRV system also shows a decrease in emissions of criteria pollutants, with a drop in HC of 7.3%; a drop in CO of 83%; and a drop in NOx of 18%.

The pintle positions are set by the throttle, with the movement of the pintles synchronized by linkage mechanisms. The fuel injectors are standard, and fuel injection timing is regulated by the electronic control unit as with a conventional manifold. Vaporization of the fuel occurs in the confined throat of the Venturi. The exit into the cylinder is contoured with an abrupt expansion ring.

With a properly designed pintle, the air flow can be regulated with the same flow characteristics as a throttle plate while facilitating the Venturi effect at all throttle positions, thereby enabling optimal air-fuel mixing throughout the operating range, according to the company.

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

October 14, 2007 in Concept Engines, Vehicle Systems | Permalink | Comments (19) | TrackBack (0)


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Is this another 100 mpg dream carburation system?

If not, why major manufactuers, with their 10000+ engineers, have not dont that or better years ago?

If this (or similar) fuel injection system can reduce CO2 by up to 83%, and gas consumption by about 20%, what could it do with E85? Would it work of large gas guzzlers?

Harvey D,
Small note, 83% reduction in CO, not CO2. Nonetheless, its still noteworthy when considering exhaust emissions.


Thank you for the correction. I assumed that (2) was missing.

What is the claimed CO2 reduction?

Would is work as well with E85?

I'm guessing that the CO2 reduction would be a result of the increased efficiency claims--14% city, 25% highway, respectively.


Your assumption makes sense. This group is apparently working on E85 and turbo-charged versions.

A 20% reduction in consumption and GHG would be worth the additional investment (if any).

I still wonder why people from Honda, Toyota, Nissan, GM, Ford, BMW, Mercedes, Renault, Peujeot etc have not come up with similar injection systems yet?

The concept saves fuel in two ways:

(a) the fluid dynamic losses due to vortices behind the butterfly are sharply reduced, though you need a long diffuser behind the injection point to avoid delamination in the case of an almost closed pintle.

(b) losses due to incomplete fuel evaporation and imperfect mixture formation are sharply reduced. These occur mostly when the engine is cold and, when the mixture is enriched to protect the catalyst at high power levels.

However, you still have throttling losses in part load because you still need a stoichiometric mixture. The figure of 14% fuel economy improvement therefore sounds quite high to me; it may apply to a very specific engine in very specific circumstances, but perhaps does not reflect the possible gain in average fuel economy across a whole drive cycle.

Could you use forced induction with this system at all, or would that require unreasonably complex pintle control to match both throttle and the amount of available boost?

What I want to know is how the system performs under real-world driving conditions rather than on a dynamometer. But the key points to me are:

*Greater fuel efficiency
*Greater torque and horsepower
*Significant reduction in carbon monoxide, NOx, and HC.


How much will further development cost? And how much would it add to the cost of a vehicle?

In theory this system is better than a plate due to enhanced aerodynamics, this is clear. But there´s something that sounds strange to me ¿what´s the reason to have better improvements in full load (25%) when a plate is completely open than in partial load (14%) when a plate is inherently inefficient.
I think that´s also important the material of what that cones are made of, it seems aluminum, but plastic would avoid condensing in cold starts.

One downside I can see to this design is a "taller" engine due to the long pintles. This would lead to an engine with a higher COG and possibly packaging issues in current production bodies.


I agree that the discrepancy between highway and city fuel economy gains is suspect. I would assume that the numbers would work the other way, especially considering that the baseline engine is SOHC and that, if I recall, the D15B does not have VVT (V-Tec).


I understand that throttling is necessary at part load and that losses will be incurred regardless of method. It seems to me, though, that your pessimism regarding the efficiency gains indicates that you think/know that a traditional butterfly throttle would be necessary with a pintle/venturi system (I respect your knowledge, just want to learn)

@ AES -

I don't see why you couldn't use the pintles in a boosted engine. You'd need to recalibrate them to account for the boost pressure, but that is measured easily enough.

@ GreenPlease -

no, the pintles DO replace the butterfly valve. It's just that I rather doubt the resulting efficiency gain will be quite as large. Most of the throttling losses in a stoichiometric spark ignition engine are due to the fact that the pistons have to produce a partial vacuum during the intake stroke in part load. The fluid dynamic losses due to shape of the throttle as such are comparatively small.

Only if the pintles are fully opened for only part of the intake stroke and then fully closed again (cp. Mahle's air impulse valves) would you really reduce the throttling losses considerably. However, this implies opening and closing the pintles very quickly indeed. The article doesn't make that claim.

Btw, the pintles can be mounted horizontally or at any other angle.

This should have been done on an old engine with little VVT control. I think is a clever idea as it is simpler than VVT and it will achieve better efficiency.

In re: comments,

1. - Who cares if ethanol has been tested with this or not? It's an inferior fuel with considerably less energy per unit than any of the other liquid transportation fuels currently available on the market...
2. - IIRC, the '93 JDM-spec D15b doesn't have VVT.


The better improvement is not at high load it is at Highway speeds (when the load is actually much lower than during city driving as it is likely to be steady state instead of requiring more acceleration.

This is similar, in manufacturing requirements IMO, to multiple throttle body layouts (Nissan's RB26DETT, and I think some Porsche engines?). It is not already done on every engine probably due to the cost of re-tooling, packaging, and producing these (single throttle body with a cast manifold versus making multiple pintles & linkage). Multi-throttle body setups have always been great for making power but they are not nearly as cost effective as a single throttle body.

Wouldn't the system need to use a MAF sensor instead of a MAP sensor?

Dutchman,Inc has developed what they call the " Hydro Assist Fuel Cell " that they are now conducting training classes to train Master Mechanics and/or Automotive Engineers to become " INSTRUCTORS " . They began the training sessions on 06/25/07 . Over 70 have completed the 3 day course and returned to their individual home domains to begin training the local mechanics to become " Authorized Installers " . They will " GUARANTEE " a 50% fuel economy improvement if the units are either installed or calibrated by an " Authorized Installer " . They have modified 24 vehicles during the class sessions
with an average fuel improvement of 95% . Anyone with good mechanical knowledge can install these units , however it is recommended that the computer , called the " optimizer " , be fine tuned by an authorized installer plus that will activate the 50% fuel improvement guarantee .

As soon as they feel there is a sufficient network of installers to cover the demand , television advertising will commence . This is a possibility as soon as mid-November

Then , sometime near year end they will introduce what they cal the " Pre Ignition Catalytic Converter " which was tested on a dynomometer with a Chrysler 318 engine . The test results was taking this engine from 22.7 MPG to 196 MPG .

These technologies may just save the v-8 engine and SUVs from extinction .

These units will " ONLY " be available through the dealership network of 2,000 Better World Technologies and their affiliates . No chance of suppression by TPTB .

For anybody that finds it hard to believe what James stated above - there is a video you can watch.....
Will make it easier to judge.....
Just click my name.


This car drives from Golden, CO to Colorado Springs, CO to be put on my Dyno. He drives it everyday so he has tons of data logs that are not dyno related. He only gets tuned on my Dyno.

sir i want complete article on this topic .
please provide me .

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