ELECTRIC BOOSTING ASSEMBLY

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This PCT Patent Application claims the benefit of and priority to U.S.

Provisional Patent Application Serial No. 62/030,924 filed July 30, 2014, the entire disclosure of the application being considered part of the disclosure of this application, and hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0002] This invention relates generally to a boosting assembly for supercharging an internal combustion engine and throttle energy recovery. The subject invention is also related to a method of supercharging an internal combustion engine and throttle energy recovery.

2. Description of the Prior Art

[0003] Boosting assemblies of the type to which the subject invention pertains generally connect to internal combustion engines used in vehicles. One such boosting assembly is illustrated in U.S. Patent No. 6,922,995 B2 to Kawamura et al. wherein a compressor includes a housing and a first shaft rotatably supported by the housing on an axis. A positive displacement compressor rotor is supported by the first shaft for rotation about the axis for compressing intake air entering the housing. An intake tube that is hollow connects to the housing and defines an inlet port for receiving the intake air from an air source. An outlet tube connects to the housing and defines an outlet port for communicating with an internal combustion engine. A motor-generator that is driven by electrical energy is connected to the first shaft for rotating the first shaft and the compressor rotor in a supercharged mode and for generating electrical energy in a non-supercharged mode. The boosting assembly operates by drawing intake air into an internal combustion engine and compressing the intake air in the supercharged mode to supercharge the internal combustion engine with increased air. However, the amount of energy that can be extracted by such an assembly may be limited by the efficiency of energy extraction using a positive displacement compressor rotor. It would thus be desirable to provide a solution for more efficiently extracting energy in the non-supercharged mode.

SUMMARY AND ADVANTAGES OF THE INVENTION

[0004] The invention provides for such a boosting assembly and further includes a second shaft rotatably supported by the housing. A turbine is attached to the second shaft and is rotatable about the axis for rotating in response to the intake air entering the inlet port. The turbine and second shaft define a second stage for generating supplemental electrical energy in the non-supercharged mode. A transfer mechanism moves the turbine between the non-supercharged mode to extract supplemental energy from the intake air and the supercharged mode.

[0005] Additionally, the invention provides for a method of extracting supplemental energy from the intake air in the second stage preceding the first stage in the non- supercharged mode. More specifically, this is done by extracting supplemental energy from the intake air in a second stage preceding the first stage in the non-supercharged mode and producing supplemental electrical energy from the supplemental energy.

[0006] Thus, several advantages of one or more aspects of the invention are that the invention extracts energy more efficiently in the non-supercharged mode while still maintaining the ability to properly supercharge an internal combustion engine and improve fuel economy. Any additional cost to install this on a vehicle is minimized since it is integrated with an electric supercharger that may already be part of the vehicle assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

[0008] Figure 1 A is a cross-sectional view of a first embodiment of the boosting assembly;

[0009] Figure 1 B is a perspective view of the turbine of the boosting assembly;

[0010] Figure 1C is a perspective view of the compressor rotor of the boosting assembly;

[0011] Figure 2 is a cross-sectional view of a second embodiment of the boosting assembly;

[0012] Figure 3 is a cross-sectional view of a third embodiment of the boosting assembly;

[0013] Figure 4 is a flow chart illustrating the steps of a method of supercharging an internal combustion engine with throttle energy recovery; and

[0014] Figure 5 is a flow chart illustrating the steps of a method of supercharging an internal combustion engine with throttle energy recovery.

DETAILED DESCRIPTION OF THE ENABLING EMBODIMENTS

[0015] During operation of an internal combustion engine, some energy is lost due to "pumping losses" or energy required to draw air into the engine and exhaust air and gases through an exhaust system. Some known solutions to reduce pumping losses in an engine include, but are not limited to cylinder deactivation, continuously variable valve lift, exhaust gas recirculation, and turbines. Boosting assemblies capable of energy recovery that are currently available may also have the capability of boosting and recovering kinetic energy of air moving through an intake system of an engine. However, current boosting assemblies do not efficiently extract this available kinetic energy or throttle energy. Due to continuous demands for improved fuel economy and efficiency, there are many instances in which it would be useful for a boosting assembly to more efficiently extract available kinetic energy of air moving through an engine intake system.

[0016] In general, the present disclosure relates to boosting assemblies of the type well-suited for use in virtually all motor vehicle applications. The boosting assembly of this disclosure will be described in conjunction with one or more example embodiments.

However, the specific example embodiments disclosed are merely provided to describe the inventive concepts, features, advantages, and objectives with sufficient clarity to permit those skilled in the art to understand and practice the disclosure. More specifically, the present disclosure relates to a boosting assembly for extracting supplemental energy or throttle energy from intake air moving through an intake system in a non-supercharged mode and for compressing the intake air in a supercharged mode.

[0017] Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, boosting assemblies 20, 120, 220 for supercharging an internal combustion engine and throttle energy recovery are shown in FIGS. 1 -3.

[0018] FIGS. 1A-1C illustrate a boosting assembly, generally shown at 20, constructed in accordance with a first embodiment of the present invention. The boosting assembly 20 includes a compressor 22, generally indicated, including a housing 24 and a first shaft 26 rotatably supported by the housing 24 on an axis A and a compressor rotor 28 (FIG. 1C) supported by the first shaft 26 and rotatable about the axis A for compressing intake air entering the housing 24. The housing 24 of the boosting assembly 20, is disclosed as being scroll or volute shaped. The interior of the housing 24 preferably has a cross- sectional area that increases circumferentially and is greatest closest to the outlet tube 30 (i.e., the compressor scroll region). However, it should be appreciated that the housing 24 may alternatively be shaped differently than a scroll or volute shape and its interior may have various cross-sections without departing from the scope of the subject disclosure. The compressor rotor 28, first shaft 26, and housing 24 define a first stage of the boosting assembly 20. The compressor 22 of the disclosed embodiments of the boosting assembly 20, 120, 220 is of the centrifugal type, but it should be appreciated that the boosting assemblies 20, 120, 220 could alternatively utilize other types of compressors 22.

[0019] A hollow intake tube 32 extends axially away from the housing 24 and defines an inlet port 34 having a circular cross-section for receiving the intake air from an air source. An outlet tube 30 is also connected to and extends tangentially from the housing 24 and defines an outlet port 36 that has a circular cross section for communicating with an internal combustion engine (e.g. directing air into an intake manifold of the engine). The inlet port 34 and outlet port 36 may alternatively have different shaped cross-sections such as, but not limited to, square, rectangular, or oblong without departing from the scope of the subject disclosure.

[0020] A motor-generator 38 is driven by electrical energy and is connected to the first shaft 26 for rotating the first shaft 26 and the compressor rotor 28 in the supercharged mode and for generating electrical energy in the non-supercharged mode. Although the disclosed embodiments include a single motor-generator 38, it should be appreciated that a separate motor and separate generator may be used so that they may be mechanically linked (e.g., sharing a common shaft) and operate much like a combined motor-generator 38 would, or the separate motor and generator may even be used in a way in which they are not mechanically linked.

[0021] A second shaft 40 extends axially away from first shaft 26 in the intake tube

32 and is rotatably supported by the housing 24. A turbine 42 (FIG. IB) is attached to the second shaft 40 and is rotatable about the axis A for rotating in response to the intake air entering the inlet port 34. The second shaft 40 and turbine 42 define a second stage of the boosting assembly 20 for generating supplemental electrical energy in the non-supercharged mode. The turbine 42 is an axial turbine 42 in the disclosed embodiments, but it should be appreciated that other types of turbines 42, such as, but not limited to a radial turbine 42 may be used. Although the second shaft 40 and turbine 42 are used for generating supplemental electrical energy in the disclosed embodiments, they may also perform a throttling function by reducing the flow of the intake air into the boosting assembly 20 and into the internal combustion engine.

[0022] A transfer mechanism 44, 46, 48 is used for moving the turbine 42 between the non-supercharged mode to extract supplemental energy from the intake air and the supercharged mode. The transfer mechanism 44, 46, 48 in the disclosed embodiments comprises a clutch 44 moveable between a disengaged position and an engaged position. It should be appreciated that the transfer mechanism 44, 46, 48 could comprise other components or devices without departing from the scope of the disclosure. The clutch 44 interconnects the first shaft 26 in the first stage and the second shaft 40 in the second stage to mechanically link the first shaft 26 and the second shaft 40 to rotate in unison in the non- supercharged mode in response to the second shaft 40 rotating faster than the first shaft 26. The clutch 44 of the disclosed embodiments is an overrunning clutch 44, but it should be appreciated that other types of clutches 44 such as, but not limited to ratchets or freewheels may be used instead without departing from the scope of the subject disclosure. It should be appreciated that although the second shaft 40 is disclosed as extending along the same axis A as the first shaft 26 in all three disclosed embodiments, it may alternatively be operatively connected to the first shaft 26 in other ways such as, but not limited to being connected through a chain or belt. The second shaft 40 may alternatively be connected to a separate generator in the embodiment described above with separate motor and generator. The transfer mechanism 44, 46, 48 may also comprise a valve 46, 48 as disclosed in a second embodiment of the boosting assembly 120 (FIG. 2) and a third embodiment of the boosting assembly 220 (FIG. 3) for directing the intake air to the intake tube 32 and bypassing the turbine 42 in the supercharging mode and for directing the intake air to the turbine 42 in the non-supercharged mode. These embodiments are discussed in more detail below.

[0023] FIG. 2 illustrates the second embodiment of the boosting assembly, generally shown at 120, in which a separator 50 having an opening 52 is disposed in the intake tube 32 and extends radially and perpendicularly from the axis A to attach to the intake tube 32. A tubular protrusion 54 has a tapered neck 56 and defines an aperture 58. The tubular protrusion 54 extends outwardly from the intake tube 32 and is aligned with the separator 50. A bypass tube 60 is attached to and interconnects the intake tube 32 and the outlet tube 30. The second shaft 40 extends through the opening 52 of the separator 50 into the bypass tube 60. The turbine 42 is disposed on the second shaft 40 in the bypass tube 60 and is axially spaced from the separator 50. A valve plate 46 is attached to the separator 50 and is movable between a first position and a second position. In the first position, the valve plate 46 engages the tapered neck 56 of the tubular protrusion 54 for directing the intake air to the intake tube 32 and bypassing the turbine 42. In the second position, the valve plate 46 engages the tapered neck 56 of the tubular protrusion 54 for directing the intake air to the bypass tube 60 and bypassing the compressor rotor 28.

[0024] FIG. 3 illustrates the third embodiment of the boosting assembly, generally shown at 220, in which the intake tube 32 defines a first bore 62 and a second bore 64 both extending perpendicular to the axis A through the intake tube 32. The boosting assembly 20 of the third embodiment further includes a bypass pipe 66 extending axially in parallel with the intake tube 32. The bypass pipe 66 is attached to the intake tube 32 and connects to the first bore 62 and to the second bore 64 for bypassing the turbine 42. A valve door 48 is disposed in the second bore 64 and attaches to the intake tube 32. The valve door 48 is movable to a first location to engage the intake tube 32 for directing the intake air to the turbine 42 and movable to a second location to engage the bypass pipe 66 for directing the intake air to the compressor rotor 28 and bypassing the turbine 42.

[0025] A method of operating the boosting assemblies 20, 120, 220 to supercharge an internal combustion engine with throttle energy recovery is also disclosed. As illustrated in FIGS. 4 and 5, the method includes the step of 300 drawing intake air into the internal combustion engine in the supercharged mode and in the non-supercharged mode.

[0026] In the supercharged mode, the method includes the step of 301 compressing the intake air at a first stage to supercharge the internal combustion engine with increased air (FIG. 4). More specifically, the method includes the step of 302 applying electrical energy to the motor-generator 38 to drive the compressor rotor 28. Next, the method includes 304 rotating the first shaft 26 and the compressor rotor 28 with the motor-generator 38 and 306 compressing the intake air with the compressor rotor 28. Consequently, a first air pressure PI entering the boosting assembly 20 (e.g. through the inlet port 34 or through the aperture 58 of the tubular protrusion 54) is less than a third air pressure P3 exiting the boosting assembly 20 through the outlet port 36. The method then includes the step of 308 forcing air into the internal combustion engine to supercharge the internal combustion engine.

[0027] In the non-supercharged mode, the method includes the step of 310 extracting energy from the intake air with the compressor rotor 28 and 312 applying the extracted energy to the motor-generator 38 to generate electrical energy. Next, the method includes the step of 314 extracting supplemental energy from the intake air in the second stage preceding the first stage. This is accomplished by 316 rotating the second shaft 40 with the turbine 42 and 318 rotating the first shaft 26 and the second shaft 40 in unison with the clutch 44. The air entering the boosting assemblies 20, 120, 220 at the first pressure PI decreases in pressure as it passes through the turbine 42 so that a second air pressure P2 present downstream from the turbine 42 (e.g. between the turbine 42 and compressor rotor 28) is less than the first pressure PI. The method concludes with the step of 319 producing supplemental electrical energy from the supplemental energy (FIG. 4). More specifically, this is done by 320 generating supplemental electrical energy from the supplemental energy with the motor-generator 38. The step of extracting supplemental energy and producing supplemental electrical energy is in response to a predetermined magnitude of operation of the first stage in the non-supercharged mode. In other words, the clutch 44 mechanically links the first shaft 26 and the second shaft 40 to rotate in unison in response to the second shaft 40 rotating faster than the first shaft 26. The flow of the intake air is in a constant direction through the second stage and the method includes the step of rotating the axial turbine 42 with the intake air. Although the method may include the extraction of energy using the compressor rotor 28, it should be appreciated that this part of the method may also be excluded and energy may only be extracted using the turbine 42 in the second stage.

[0028] Additional method steps are disclosed for the second embodiment (FIG. 2).

The method of operating the second embodiment of the boosting assembly 20 includes the step of moving the valve plate 46 to the first position to engage the tubular protrusion 54 in the supercharged mode. This allows the supercharging by directing the intake air to the intake tube 32 and bypassing the turbine 42 in the supercharged mode. In the non- supercharged mode, the next step of the method is moving the valve plate 46 to the second position to engage the tubular protrusion 54. This is followed by directing the intake air to the turbine 42 and bypassing the compressor rotor 28 in the non-supercharged mode.

[0029] Additional method steps are disclosed for the third embodiment (FIG. 3).

The method of operating the third embodiment of the boosting assembly 20 includes the step of moving the valve door 48 to the first location to engage the bypass pipe 66 in the supercharged mode. This allows the supercharging by directing the intake air to the compressor rotor 28 and bypassing the turbine 42. In the non-supercharged mode, the method includes moving the valve door 48 to the second position to engage the intake tube 32 and directing the intake air to the turbine 42.

[0030] The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims. The use of the word "said" in the apparatus claims refers to an antecedent that is a positive recitation meant to be included in the coverage of the claims whereas the word "the" precedes a word not meant to be included in the coverage of the claims. In addition, the reference numerals in the claims are merely for convenience and are not to be read in any way as limiting.