VARIABLE A/R TURBINE HOUSING

Abstract

A turbocharger having a housing. The housing may have a scroll formed therein. The scroll may include a passageway leading between an exhaust inlet and a turbine wheel. A valve or valves may be disposed within the passageway. The valve may regulate airflow through the passageway.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/801,332, filed Mar. 15, 2013, which is hereby incorporated by reference herein in its entirety, including but not limited to those portions that specifically appear hereinafter, the incorporation by reference being made with the following exception: In the event that any portions of the above-referenced application are inconsistent with this application, this application supercedes said above-referenced application.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND

1. The Field of the Present Disclosure.

The present disclosure relates generally to engines, and more particularly, but not necessarily entirely, to turbochargers used with engines.

2. Description of Related Art.

In piston engines, intake gases are pulled into the cylinder by the downward stroke of the piston (which creates a low-pressure area). The amount of air which is actually pulled into the engine is often the limiting factor in the performance of the engine. In the past, to overcome the limitations of inadequate air supply, engines are equipped with turbochargers.

A turbocharger may compress air that is supplied to the combustion chambers of an engine. In particular, a turbocharger may supply air at a higher pressure and higher density than would otherwise be possible. Thus, the objective of a turbocharger is to improve an engine's volumetric efficiency by increasing the density of the intake air. Stated another way, turbochargers allows engines to squeeze more air into a cylinder, which means that more fuel can also be added to the cylinder. Therefore, more power is produced from each explosion in each cylinder.

Most modern turbochargers include a turbine driven compressor. Typically, a turbocharger is bolted to the exhaust manifold. The exhaust from the cylinders spins the turbine. In particular, the exhaust spins the turbine as it passes through the blades of the turbine. The more exhaust that passes through the blades, the faster the turbine spins.

The turbine is connected by a shaft to a compressor, which is located between the air filter and the intake manifold. The compressor pressurizes the air going into the piston cylinders. The compressor is a type of centrifugal pump that draws air in at the center of its blades and flings it outwards as it spins. An exemplary prior art turbocharger design is depicted in FIG. 1.

One of the main problems with turbochargers is that they function in a very limited range of RPM, horsepower and engine size. (This limitation is often referred to as “turbo lag.”) That is, a turbocharger may not provide an immediate boost when the throttle is increased because it takes a few seconds for the turbocharger's turbine to get up to speed before boost is produced. Two main things affect exhaust gas flow through the turbine wheel. The first is the turbine wheel size, the second is the scroll area over radius ratio (“A/R ratio”.) The turbine housing is often conceptualized as a cone wrapped around a wheel to look like a snail. Unwrapping this cone and cut off the small end a short distance from the tip. A groove is cut into the cone, allowing exhaust gasses to escape relatively uniformly along the entire groove into the turbine wheel. The groove would be cut on the inside of the scroll so the exhaust gasses exit the middle hole where the turbine is and cause the turbine wheel to rotate, as the gasses pass through the turbine wheel. The smaller and shorter the cone (or scroll), the faster the velocity of the gasses exiting the groove and end, and therefore the faster the turbine wheel will spin, and higher the exhaust gas pressures will be. Volume will be more restricted as well, but the turbine spool-up time will be much shorter. However the longer the cone (or scroll) is the opposite is true. The exhaust gasses will be moving slower because there is a larger exit groove and end hole, and therefore pressure will be lower, and turbine speed will be slower. While volume will be higher the spool-up time will be longer. The difference in cone (or scroll) sizes is illustrated in FIGS. 2A and 2B. In particular, FIG. 2A depicts a large cone (or scroll) that results in low velocity and high volume. FIG. 2B depicts a small cone (or scroll) that results in high velocity and low volume.

One way to decrease turbo lag is to reduce the inertia of the rotating parts, mainly by reducing their weight. Weight reduction allows the turbine and compressor to accelerate quickly, and start providing boost earlier. One way to reduce the inertia of the turbine and compressor is to make the turbocharger smaller (see FIG. 2B). A small turbocharger will provide boost more quickly and at lower engine speeds, but may not be able to provide much boost at higher engine speeds when a really large volume of air is going into the engine. It is also in danger of spinning too quickly at higher engine speeds, when lots of exhaust is passing through the turbine. Likewise, a large turbocharger may provide boost at higher engine speeds, but may not be able to provide much boost at lower engine speeds. (See FIG. 2A)

To overcome turbo lag, some engines use two turbochargers of different sizes. The smaller one spins up to speed very quickly, reducing lag, while the bigger one takes over at higher engine speeds to provide more boost. However, the use of two turbochargers is cost and space prohibitive in some applications. It would therefore be an improvement over the prior art to provide a single turbocharger that is able to reduce turbo lag, but still provide boost at higher speeds.

The prior art is thus characterized by several disadvantages that are addressed by the present disclosure. The present disclosure minimizes, and in some aspects eliminates, the above-mentioned failures, and other problems, by utilizing the methods and structural features described herein.

The features and advantages of the present disclosure will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by the practice of the present disclosure without undue experimentation. The features and advantages of the present disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the disclosure will become apparent from a consideration of the subsequent detailed description presented in connection with the accompanying drawings in which:

FIG. 1 is a diagram of a prior art turbo charger;

FIGS. 2A and 2B depict airflow through a scroll of a turbocharger;

FIG. 3 depicts a turbocharger according to an embodiment of the present invention;

FIG. 4 depicts a turbocharger according to an embodiment of the present invention;

FIGS. 5A and 5B depict a cross-sectional view of a scroll of a turbocharger, of an embodiment of the present invention;

FIGS. 6A and 6B depict airflow through a scroll of a turbocharger according to an embodiment of the present disclosure;

FIG. 7 depicts a turbocharger according to an embodiment of the present invention;

FIG. 8 depicts a turbocharger according to an embodiment of the present invention;

FIGS. 9, 10 and 11 depict airflow through a scroll of a turbocharger according to an embodiment of the present disclosure;

FIGS. 12A and 12B depict airflow through a split-scroll of a turbocharger according to an embodiment of the present disclosure; and

FIG. 13 depicts a turbocharger according to an embodiment of the present invention.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles in accordance with the disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the disclosure as illustrated herein, which would normally occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the disclosure claimed.

In describing and claiming the present disclosure, the following terminology will be used in accordance with the definitions set out below.

As used herein, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

As used herein, the terms “comprising,” “including,” “containing,” “having,” “characterized by,” and grammatical equivalents thereof are inclusive or open-ended terms that do not exclude additional, unrecited elements or method steps.

As used herein, the term “spool-up” refers to the amount of time it takes a turbo to actually start building positive boost pressure. For example, a quick spool-up would mean that a turbo builds positive boost pressure quickly or at relatively low engine RPM's, while slow spool-up means a turbo would build positive boost pressure more slowly or at higher engine RPM's.

As used herein, the term “turbine Scroll” may refer to the snail shaped cone wrapped around the turbine wheel, the center or turbine wheel area is the discharge area for the gasses.

As used herein, the term “A/R ratio” may refer to the area over the radius ratio, of the cross section area of the scroll over the radius from the center of the turbine wheel to the center of the area cross section. In other words, if the scroll were straightened out, the shorter the scroll the lower the A/R ratio, the longer the scroll the higher the A/R ratio. A/R ratio effects the speed and pressure that the exhaust gas hits the turbine wheel.

The present disclosure comprises a standard type turbine housing scroll, with a butterfly-type valve placed in the scroll such that at low engine RPMs or when higher turbine speeds are needed, the butterfly valve will be in a closed or nearly closed position. This may cause the effective length of the scroll to be smaller, so that it will behave like a smaller A/R turbine housing. This may increase the gas pressure and velocity. This may give the benefit of having the turbocharger spool-up time less, and allow the turbocharger to build positive pressure at much lower engine RPMs.

Once the turbocharger is building positive boost pressure, the butterfly valve may be either partially, or fully opened to allow the gasses to bypass the valve. This may lower the exhaust gas pressure, and allow a higher volume of exhaust gas to pass through the turbine housing, while keeping turbine speeds reasonable.

Some of the benefits of the present invention may be:

Quicker low RPM spool-up, without sacrificing high engine RPM performance.

Cleaner low end emissions.

Reduced turbo surge.

Will allow a much larger turbocharger to be used, and be street drive able.

In an embodiment of the present disclosure, two or more butterfly valves may also be used and opened or closed in stages, so that the turbine A/R ratio can be changed multiple times. The butterfly valves may be placed at different points in the scroll. In split scroll turbine housings, two buttery valves may be required on the same pivot, each valve located in either side of the split scroll.

Referring now to FIGS. 3 and 4, there is depicted a turbocharger 100 according to an embodiment of the present disclosure. The turbocharger 100 may include a housing 102. The housing 102 may include a scroll 104. The housing 102 may further include an exhaust inlet 105 that connects to an exhaust system (not shown) of an engine. Disposed in the center of the housing 102 may be a turbine wheel 106 having a plurality of blades 108. The turbine wheel 106 may be connected to a shaft that drives an air compressor (not shown).

A passageway 110 may be defined by the scroll 104 of the housing 102. The passageway 110 may lead from the exhaust inlet 105 to the turbine wheel 106. A valve 112 may be disposed in the passageway 110. In an embodiment, the valve 112 includes a plate 114 mounted on a control shaft 116. The control shaft 116 may be connected to a drive (not shown). The drive may be vacuum driven, electrically driven, hydraulically driven or mechanically driven. The drive may be operable to rotate the shaft 116 to thereby open and close the valve 112.

Referring now to FIGS. 3, 4, 5A and 5B, the valve 112 may be operable between an open position as shown in FIGS. 3 and 5A, or a closed position as shown in FIGS. 4 and 5B. The valve 112 may also be operable to one or more intermediate positions between the open position and the closed position.

In an embodiment, the valve 112 may be a butterfly valve. The valve 112 may be pivotally mounted in the center of the plate 114, so that equal or near equal pressures may exist on both sides of the valve 112 so that a small opening or closing force can be applied to open or close the valve. In an embodiment, the plate 114 may include a curvature, to match the curvature of the scroll 104, or may be straight as shown by FIG. 5a (item 112).

Referring now to FIG. 6A, there is shown a conceptual diagram of the scroll 104, as if straightened out to demonstrate the scroll length, of the turbocharger 100 with the valve 112 in the open position. In this case, the exhaust flowing through the scroll 104 may have a low velocity and high volume. Referring now to FIG. 6B, there is shown a conceptual diagram of the scroll 104, as if straightened out to demonstrate the scroll length, of the turbocharger 100 with the valve 112 in the closed position. In this case, the exhaust flowing through the scroll 104 may have a high velocity and a low volume.

Referring now to FIGS. 7 and 8, there is depicted a turbocharger 200 having a housing 202. The housing 202 may comprise a scroll 204 having a passageway 206 formed therein. The scroll 204 may having an exhaust inlet 208 that leads into the passageway 206. The housing 202 may further comprise a turbine wheel 210 having a plurality of blades 212.

Disposed in the passageway 206 may be a first valve 212 and a second valve 214. The first valve 212 and the second valve 214 may have similar components to, and function the same as, the valve 112 described above. The first valve 212 and the second valve 214 may be alternately closed as perhaps best shown in FIGS. 9, 10, and 11, thereby changing the velocity and volume of the exhaust gasses respectively.

Referring now to FIGS. 12A and 12B, there is depicted a valve 250 for use in a turbocharger having a split scroll 252. In particular, the valve 250 may include a shaft 254. A first plate 256 and a second plate 258 may be mounted to the shaft 254. The valve 250 may be operable between an open position (see FIG. 12A) and a closed position (see FIG. 12B).

Referring to FIG. 13, there is depicted a turbocharger 300 according to an embodiment of the present disclosure. The turbocharger may include a housing 301. The housing may comprise a scroll 302. The scroll 302 may include a slot 304. An insert 306 may be configured and adapted to be installed into slot 304. The insert 306 may include a valve 308 that is positionable between an open position and a closed position. The valve 308 may take the form of the valve 112, described above. The insert 306 may be secured to the housing 301 of the turbocharger 300 by fasteners, such as bolts. Once the insert is fastened into place in the scroll 302, the valve 308 may function in a manner similar to FIG. 3 and FIG. 4.

Using the embodiments described herein, it will be appreciated that an airflow through a scroll of a turbocharger may be varied by adjusting a valve in the scroll based upon the speed of the engine. In particular, at low engine speeds, the valve in the scroll may be closed. At high engine speeds, the valve may be opened. At intermediate engine speeds, the valve may be positioned at intermediate steps between the open position and the closed position.

In accordance with the features and combinations described above, a useful method of turbocharging an engine includes the steps of:

(a) installing a turbocharger onto the engine, the turbocharger having a scroll; and

(b) adjusting a valve in the scroll to thereby regulate an airflow through the scroll based upon a speed of the engine, or amount of desired boost.

An embodiment of the present disclosure may include a turbocharger, the turbocharger having a housing having a turbine wheel disposed therein, the housing may further include a scroll having an inlet for receiving exhaust, a passageway may be formed within the scroll, a slot opening at the inside of the scroll may be included to cause exhaust to exit into the turbine wheel. Further, disposed in the passageway may be a valve operable between an open position and a closed position.

An embodiment of the present disclosure may include a turbocharger, the turbocharger having a housing having a turbine wheel disposed therein, the housing may further include a scroll having an inlet for receiving exhaust, a passageway may be formed within the scroll, a slot opening at the inside of the scroll may be included to cause exhaust to exit into the turbine wheel. Further, disposed in the passageway may be a pair of valves, each selectively operable between an open position and a closed position.

Those having ordinary skill in the relevant art will appreciate the advantages provide by the features of the present disclosure. For example, it is a feature of the present disclosure to provide a turbocharger. Another feature of the present disclosure to provide such a turbocharger with a scroll having a valve disposed therein. It is a further feature of the present disclosure, in accordance with one aspect thereof, to provide a turbocharger that provides boost at both low engine speeds and high engine speeds.

In the foregoing Detailed Description, various features of the present disclosure are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description of the Disclosure by this reference, with each claim standing on its own as a separate embodiment of the present disclosure.

It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present disclosure. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present disclosure and the appended claims are intended to cover such modifications and arrangements. Thus, while the present disclosure has been shown in the drawings and described above with particularity and detail, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, variations in size, materials, shape, form, function and manner of operation, assembly and use may be made without departing from the principles and concepts set forth herein.

Claims

1. A turbine housing of a turbocharger with butterfly-type valves pivotally positioned in the turbine housing, said butterfly-type valves being disposed within said turbine housing and configured and arranged to:

a) close and thereby shorten the overall scroll length of the turbine housing to thereby cause exhaust gases to exit into the turbine wheel in a shorter distance; and

b) open and thereby allow the exhaust gasses to travel through the longer length of the scroll.

2. The turbine housing of claim 1, wherein multiple butterfly-type valves are pivotally positioned in the turbine housing, said multiple butterfly-type valves being disposed within the turbine housing and configured and arranged to:

a) close and thereby shorten the overall scroll length of the turbine housing to thereby cause exhaust gases to exit into the turbine wheel in a shorter distance;

b) open and thereby allow the exhaust gasses to travel through the longer length of the scroll;

c) open and close at different times; and

d) open and close simultaneously.