TURBOCHARGER EGR MODULE

Abstract

A product comprising a turbine torsionally connected to a compressor, a housing for said turbine, a housing for said compressor fixed with respect to said turbine housing, and an exhaust gas recirculation valve mounted on at least one of said turbine or said compressor housings.

Description

This application claims the benefit of U.S. Provisional Application Ser. No. 61/394,023 filed Oct. 18, 2011.

TECHNICAL FIELD

The technical field generally relates to products including turbochargers for internal combustion engines having an exhaust gas recirculation valve.

BACKGROUND

Federal and State legislation require control of vehicle exhaust emissions. Oxides of Nitrogen (NOx) are one of the exhaust gas emissions that must be controlled. Formation of NOx will occur at higher combustion temperatures. A system, referred to as the exhaust gas recirculation system, has been developed to reduce excess oxygen and combustion temperatures to control NOx emissions. A portion of the exhaust gas is recirculated back to the intake where it will be combined with incoming air reducing excess oxygen content in the total air mixture. When this mixture is compressed and ignited in the cylinder, the result is a reduction in NOx due to reduced oxygen content and a lower combustion temperature. A schematic of this system is shown in FIG. 1.

The traditional system consists of the “high pressure” EGR loop, named because the EGR loop operates on the high pressure side between the engine and the turbocharger 7. This EGR loop consists of an exhaust gas recirculation (EGR) valve 1 that controls the flow of exhaust gas to the intake manifold 2. The EGR valve shown in FIG. 1 is positioned after (cold side) the exhaust gas cooler 5, but it may also be positioned before (hot side) the cooler. As the EGR valve opens and closes it will increase or decrease the flow rate of exhaust gas to the intake manifold. It is also typical to have a throttle valve 6 to control airflow and pressure in the intake manifold and, an exhaust gas cooler 5 to reduce temperature of recirculated exhaust gas, and a cooler bypass valve 4 to bypass exhaust gas around the cooler under certain operating conditions.

To further reduce NOx and improve vehicle fuel economy, recently developed engine systems may add an additional “low pressure” EGR loop that operates on the low pressure side of the turbocharger, after the exhaust turbine and before intake compressor. This system consists of another EGR valve 10 to control the flow rate of exhaust gas to the air intake, and an exhaust throttle valve 11 to control the exhaust back pressure needed to drive the exhaust gas flow. This EGR loop may also includes a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) 9, and an additional exhaust gas cooler 12. Low pressure loop exhaust gas has the additional advantage of passing through the air charge cooler 8 before reaching the engine. Similar to the high pressure loop, the low pressure loop valve can be placed either before (hot side) or after (cold side) the exhaust gas cooler.

EGR valves may be actuated by hydraulic, pneumatic, or electric means. Pneumatically actuated valves depend upon the availability of pressure or vacuum on the vehicle and this may be an undesirable requirement. They also require a means of electrically controlling the pneumatic source to allow overall electrical control of the system. An electric vacuum or pressure regulator is used to provide this control. Operating force is another factor used in the selection criteria for the type of actuator used for the EGR valve. Higher flow rates require larger valves with greater area and higher operating forces. Lower pressure differential between the exhaust and intake manifold will require larger valves to achieve the desired flow rate. Contamination in the exhaust gas can accumulate on the valve components and cause them to stick or restrict movement if sufficient operating force is not available.

The type of valve technology best suited to a particular application is at least partially driven by the required EGR flow rate. Single poppet valves are well suited for typical engine applications because of low gas leakage passed the valve when the valve is closed. Because the operating forces required typically increase with the valve size, for higher EGR flow rates in moderately sized engines dual poppet valves (two poppet valves on the same shaft) are often chosen; a dual poppet valve increases the flow capacity of a poppet valve while balancing and reducing the required operating forces. For very high EGR flow rates in large engine applications, where a poppet valve or dual poppet valve would need to be very large (>32 mm in diameter), a throttle valve (or butterfly valve) potentially becomes an attractive solution. A throttle valve is also a potentially attractive solution for “low pressure loop” EGR systems due to lower differential valve pressure and subsequent less stringent requirements for gas leakage when the valve is closed. When compared to a poppet valve: 1) a throttle valve is not typically able to achieve the low leakage rates of a poppet valve, this however is typically of less importance for very large engines. 2) a throttle valve is naturally balanced resulting in lower operating forces for very large valves. 3) a throttle valve can typically achieve a similar EGR flow rate in a smaller diameter valve because of their inherently higher flow efficiency.

EGR valves, and other valves that control the flow of high temperature fluids, may have components that are sensitive to the high temperature. These components may include: actuators, shaft seals, bearings, position sensors, and plastic molded parts. Typical actuators may include: pneumatic devices, linear solenoids, torque motors, stepper motors, and D.C. motors. Additional measures such as liquid cooling, heat shields, remote mounting, or use of expensive materials may be required to achieve suitable durability when operating at the high temperature.

SUMMARY OF SELECT EMBODIMENTS

One embodiment includes a product including a turbocharger including a turbine torsionally connected to a compressor and a compressor housing fixed to a turbine housing. An exhaust gas recirculation valve mounted on at least one of the compressor housing or turbine housing.

Other exemplary embodiments of the invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while disclosing exemplary embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a generalized schematic illustration of a prior art EGR system utilizing a turbocharger. FIG. 2 is a generalized schematic illustration EGR system utilizing a turbocharger according to one embodiment.

FIG. 3 is a perspective exploded view of a turbocharger and EGR valves according to one embodiment.

FIG. 4 is a generalized schematic illustration of another prior art EGR system utilizing a turbocharger.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

One embodiment includes integration of one or more of the EGR valves with the turbocharger. The placement of the EGR valves within the engine system architecture can be chosen such that that the exhaust gas inlet for the high pressure EGR valve 1 coincides with a junction to the inlet to the turbine of the turbo charger 7 and such that the outlet of the low pressure EGR valve 10 coincides with a junction to the inlet to the compressor of the turbo charger 7. Configuring the system in this manner allows for the potential to integrate one or more of the EGR valves into the packaging of the turbocharger assembly. A schematic of a system with a Turbo EGR module according to one embodiment is shown in FIG. 2.

The module concept can be extended further with the possibility to integrate the EGR cooler bypass valve 4, and/or a low pressure intake valve 13, and/or a gas mixer/diffuser 14 at the junction between the low pressure exhaust gas and the inlet to the compressor from a prior art system as illustrated in FIG. 4.

Another embodiment is shown pictorially in FIG. 3, in which a throttle type low pressure loop EGR valve is integrated to the inlet of the turbo compressor and/or a poppet type high pressure EGR valve is integrated to the inlet of the turbo turbine.

numerous embodiments are within the scope of the invention include but not limited to the following.

Embodiment 1 may include a product comprising: a turbocharger comprising a turbine torsionally connected to a compressor, a housing for said turbine, a housing for said compressor fixed with respect to said turbine housing; and an exhaust gas recirculation valve mounted on at least one of said turbine or said compressor housings.

Embodiment 2 may include a product as described in embodiment 1 wherein there is an exhaust gas recirculation valve mounted on said turbine and said compressor housings.

Embodiment 3 may include a product as described in any of embodiments 1-2 wherein there is a high pressure exhaust gas recirculation valve mounted on said turbine housing.

Embodiment 4 may include a product as described in any of embodiments 1-3 wherein said exhaust gas recirculation valve is a poppet type valve.

Embodiment 5 may include a product as described in any of embodiments 1-4 wherein said exhaust gas recirculation valve is water cooled.

Embodiment 6 may include a product as described in any of embodiments 1-5 wherein said exhaust gas recirculation valve has a DC motor drive.

Embodiment 7 may include a product as described in any of embodiments 1-6 further comprising a cooler bypass valve mounted to said turbine housing.

Embodiment 8 may include a product as described in any of embodiments 1-7 wherein there is a low pressure exhaust gas recirculation valve mounted on said compressor housing.

Embodiment 9 may include a product as described in any of embodiments 1-8 wherein said exhaust gas recirculation valve has a DC motor drive.

Embodiment 10 may include a product as described in any of embodiments 1-9 wherein said exhaust gas recirculation valve is a throttle type valve.

Embodiment 11 may include a product as described in any of embodiments 1-10 further comprising an exhaust gas mixing unit mounted between said compressor housing and said exhaust gas recirculation valve.

Embodiment 12 may include a product as described in any of embodiments 1-11 further comprising an intake valve mounted to said compressor housing.

Embodiment 13 may include a product comprising: a turbocharger comprising a turbine torsionally connected to a compressor, a housing for said turbine, a housing for said compressor fixed with respect to said turbine housing, and a water cooled DC motor drive poppet exhaust gas recirculation valve mounted on said turbine housing; and a DC motor drive throttle exhaust gas recirculation valve mounted on said compressor housing.

The description of the invention is merely exemplary (illustrative) in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.

Claims

1. A product comprising:

a turbocharger comprising a turbine torsionally connected to a compressor,

a housing for said turbine,

a housing for said compressor fixed with respect to said turbine housing; and an exhaust gas recirculation valve mounted on at least one of said turbine or said compressor housings wherein there is a low pressure exhaust gas recirculation valve mounted on said compressor housing.

2. A product as described in claim 1 wherein there is an exhaust gas recirculation valve mounted on said turbine and said compressor housings.

3. A product as described in claim 1 wherein there is a high pressure exhaust gas recirculation valve mounted on said turbine housing.

4. A product as described in claim 3 wherein said exhaust gas recirculation v lye is a poppet type valve.

5. A product as described in claim 3 wherein said exhaust gas recirculation valve is water cooled.

6. A product as described in claim 3 wherein said exhaust gas recirculation valve has a DC motor drive.

7. A product as described in claim 3 further comprising a cooler bypass valve mounted to said turbine housing.

8. (canceled)

9. A product as described in claim 1 wherein said exhaust gas recirculation valve has a DC motor drive.

10. A product as described in claim 1 wherein said exhaust gas recirculation valve is throttle type valve.

11. A product as described in claim 1 further comprising an exhaust gas mixing unit mounted between said compressor housing and said exhaust gas recirculation valve.

12. A product as described in claim 1 further comprising an intake valve mounted to said compressor housing.

13. A product comprising:

a turbocharger comprising a turbine torsionally connected to a compressor,

a housing for said turbine, a housing for said compressor fixed with respect to said turbine housing, and

a water cooled DC motor drive poppet exhaust gas recirculation valve mounted on said turbine housing; and

a DC motor drive throttle exhaust gas recirculation valve mounted on said compressor housing.