DESC:Field of the invention

The present invention relates to a technique for exhaust gas recirculation and more particularly, to an exhaust gas recirculation module for an internal combustion engine.

Background of the invention

Most modern engines require exhaust gas recirculation (herein after ‘EGR’) to meet emissions standards. EGR is a technique to reduce nitrogen oxide (NOx) emissions in internal combustion engines by recirculating a portion of an engine's exhaust gas back to engine cylinders to burn any unburned fuel. Reburning of the exhaust gas before it is released reduces the harmful effects of the exhaust gas on the atmosphere.

Typically, EGR systems include a valve to regulate the amount of exhaust gas that is introduced back into the engine and a cooler to cool the exhaust gas to a specified temperature which condenses the unburned fuel. Various types of the EGR systems have been disclosed in published and granted patents which include WO2009047278A1, JP03547569B2, W02009076375A2, US6647971B2, US736391981, US20130000619Al and US62112882. Several drawbacks associated with the prior art EGR systems are listed below:
• The valve and the cooler are used as separate components connected by additional tubing thereby reducing the amount of space in an engine compartment and resulting in poor control of the exhaust emission.
• Prior art EGR system designed with integrated components poses challenges for space and does not have enough strength for avoiding failure modes and for assuring functional optimization of the components.
• The valve is assembled downstream of the cooler i.e. on a cold side which increases the chance of the valve failure due to condensation.
• The valve is electrically actuated and adds to the cost of the EGR system.
• The EGR system is mounted over a pipe and over an exhaust manifold.
• The EGR system uses different inlet and outlet for coolant connections for connecting to the cooler.
• More number of components makes the EGR system bulky and prone to leakage and failure.
• The cooler inclination makes them prone to failure due to pitting of the tubes.

Accordingly, there exists a need to provide an exhaust gas recirculation module for an internal combustion engine that overcomes the above mentioned problems in the prior art.

Objects of the invention

An object of the present invention is to provide an exhaust gas recirculation module that is reduced in size and cost effective.

Another object of the present invention is to provide the exhaust gas recirculation module capable of direct mounting on a cylinder head of an engine.

Yet another object of the present invention is to provide the exhaust gas recirculation module that is easy to assemble and service.

Summary of the invention

Accordingly, the present invention provides an exhaust gas recirculation module for an internal combustion engine. The exhaust gas recirculation module comprises a housing, a valve, an actuator and a heat exchanger. The housing is made up of a material selected from cast iron and di-cast aluminium. The housing is mounted directly on a cylinder head of the internal combustion engine for providing a passage for exhaust gases and high pressure coolant, for example water.

The housing includes a first inlet, a second inlet, a first outlet and a second outlet. The first inlet is configured in fluid communication with an exhaust manifold of the cylinder head to allow recirculation of exhaust gases therefrom. The second inlet is configured in the housing to allow high pressure coolant to enter therein for cooling of the exhaust gases.

The first outlet is configured in fluid communication with an intake manifold of the cylinder head to allow recirculation of cooled exhaust gases thereto through a pipe. The pipe connects the first outlet of the housing to the intake manifold of the cylinder head. The second outlet is configured in the housing to allow the coolant with increased temperature after the heat exchange with the exhaust gases to flow out therefrom into the intake manifold.

The valve is integrated into the housing to receive the exhaust gases therefrom through the first inlet at a controlled flow rate. Typically, the valve is a pneumatically controlled valve integrated in the housing at an inclination to horizontal. The valve includes a vacuum inlet for actuation thereof.
The actuator is connected to the valve to selectively open and close the valve to receive and direct the exhaust gases therefrom. Typically, the actuator is a pneumatic / vacuum actuator.

The heat exchanger is integrated into the housing in such a way to have the valve located on a hot side thereof. Typically, the heat exchanger is a U-shape heat exchanger integrated in the housing at an inclination angle of 5 degrees to the horizontal. The heat exchanger receives the exhaust gases at a controlled flow rate from the valve and receives high pressure coolant from the second inlet to cool the exhaust gases using the high pressure coolant for sending the cooled exhaust gases into the intake manifold of the cylinder head through the first outlet.

Brief description of the drawings

Other features as well as the advantages of the invention will be clear from the following description.
In the appended drawings:
Figure 1 shows a rear perspective view of an exhaust gas recirculation module for an internal combustion engine, in accordance with the present invention;

Figure 2a shows a front perspective view of the exhaust gas recirculation module of figure 1;

Figure 2b is a cut sectional view of the exhaust gas recirculation module of figure 2a showing a valve;

Figure 3 shows an exploded view of the exhaust gas recirculation module of figure 1;

Figures 4a and 4b show flow directions in the exhaust gas recirculation module of figure 2a;

Figure 5 shows a perspective view of an assembly of the exhaust gas recirculation module mounted on a cylinder head of the engine, in accordance with the present invention; and

Figure 6 shows an exploded view of the assembly of figure 5.

Detailed description of the invention

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.

The present invention provides an exhaust gas recirculation module (herein after ‘the module’) for an internal combustion engine. The module is capable of direct mounting on a cylinder head of the engine. The module is compact in size due to integration of parts thereof and thus cost effective, easy to assemble and easy to service.

This present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.

Referring now to figures 1 to 6, an exhaust gas recirculation module (100) (hereinafter “the module (100)”) for an internal combustion engine (not shown) of a vehicle (not shown), in accordance with the present invention is shown. Specifically, the internal combustion engine (herein after ‘the engine’) is an in-line internal combustion engine such as a petrol/gasoline engine and a diesel engine. The engine includes a cylinder head (150). The cylinder head (150) includes an intake manifold (140) and an exhaust manifold (not shown). The atmospheric air enters into the intake manifold (140) and mixes with the fuel for combustion inside the cylinder head (150). The exhaust gases resulting from the combustion escapes to the atmosphere through the exhaust manifold with some volume entering into the module (100). Specifically, the module (100) is mounted directly in the cylinder head (150). The module (100) comprises a housing (90), a valve (60), an actuator (not shown) and a heat exchanger (50).

The housing (90) is a structural part that allows all sub-components to be assembled thereon. In an embodiment, the housing (90) is made up of a material selected from any of cast iron and di-cast aluminium. However, it is understood that the housing (90) can be made from any other suitable material known in the art. The housing (90) is mounted directly on the cylinder head (150) of the engine thereby mounting the module (100) directly on the cylinder head (150) for providing a passage for exhaust gases and high pressure coolant (herein after ‘the coolant’), for example water. The housing (90) includes a first inlet (80), a second inlet (75), a first outlet (70) and a second outlet (65) configured therein.

The first inlet (80) is configured in the housing (90) in fluid communication with the exhaust manifold of the cylinder head (150). The first inlet (80) connects the housing (90) to the internal passage provided inside the cylinder head (150). The first inlet (80) is adapted to allow recirculation of exhaust gases from the exhaust manifold to enter therein and then to the valve (60).

The second inlet (75) alternatively referred as a coolant inlet connection is configured in the housing (90) to allow coolant to enter therein and then to the heat exchanger (50) for cooling of the exhaust gases therein.

The first outlet (70) is configured in the housing (90) in fluid communication with the intake manifold (140) of the cylinder head (150) to allow recirculation of cooled exhaust gases from the heat exchanger (50) through a pipe (40) into the intake manifold (140). Thus, the pipe (40) connects the first outlet (70) of the housing (90) to the intake manifold (140) of the cylinder head (150). The first outlet (70) is positioned in such a way that the pipe (40) is compact.

The second outlet (65) is alternatively referred as a coolant outlet connection and also a coolant outlet spigot. The second outlet (65) is configured in the housing (90) to allow coolant with increased temperature after the heat exchange with exhaust gases to flow out from the heat exchanger (50) into the intake manifold (140).

The valve (60) is integrated into the housing (90). Specifically, the valve (60) is integrated in the housing (90) at an inclination to horizontal to receive the exhaust gases therefrom through the first inlet (80) at a controlled flow rate. Preferably, the valve (60) is a pneumatic controlled vacuum actuated valve. The valve (60) includes a vacuum inlet (55) configured therein for vacuum actuation thereof. However, it is understood that any other suitable type of valve known in the art can be used. The valve (60) is configured on a hot side (not numbered) of the heat exchanger (50) to provide exhaust gases at a controlled flow rate. The flow rate is controlled based on the level of actuation of the vacuum inlet (55) of the valve (60) by the actuator. The valve (60) provides the throttle for the exhaust gas recirculation mass flow rate as per the engine operating parameters and requirements.

The actuator is connected to the valve (60) to selectively open and close the valve (60) by actuation of the vacuum inlet (55). The valve (60) upon actuation receives the exhaust gases through the first inlet (80) of the housing (90) and directs the exhaust gases therefrom to the heat exchanger (50). In an embodiment, the actuator is a pneumatic/vacuum actuator. However, it is understood that any other suitable types of actuator known in the art can be used for actuating the valve (60).

The heat exchanger (50) is integrated into the housing (90). Specifically, the heat exchanger (50) is integrated into the housing (90) at an inclination angle of 5 degrees to the horizontal in such a way to have the valve (60) located on the hot side thereof. In an embodiment, the heat exchanger (50) is a U-shape heat exchanger. However, it is understood that the heat exchangers of any types and shapes can also be used. The heat exchanger (50) is adapted for receiving the exhaust gases from the valve (60) and the coolant from the second inlet (75). The heat exchanger (50) receives the exhaust gases from the valve (60) at a flow rate that is controlled by the actuator. The heat exchanger (50) cools the exhaust gases using the coolant to a requisite temperature as per the emission norm compliance. The flow rate of the coolant is varied as per the engine operating parameters. The heat exchanger (50) plays an important role in reducing the nitrogen oxide (NOX) in the exhaust gases.

The heat exchanger (50) sends the cooled exhaust gases into the intake manifold (140) of the cylinder head (150) through the first outlet (70) via the pipe (40). Further, the coolant with increased temperature after the heat exchange with exhaust gases also passes out from the heat exchanger (50) into the air intake manifold (140) through the second outlet (65).

Advantages of the invention

1. The module (100) is cost effective and improved in stiffness due to direct mounting on the cylinder head (150) that results in elimination of the EGR pipe and extra brackets which otherwise are required for connecting and supporting the module (100) onto the cylinder head (150).
2. The module (100) is easy to assemble and service and gives advantage in over all engine weight, packaging space and more fuel economy.
3. The housing (90) being made up of cast iron material has sufficient strength at high temperatures and thus, eliminates the need of having a separate water jacket for cooling thereof.
4. The module (100) is made compact by integrating and bringing the valve (60) and the heat exchanger (50) in modular concept as integral parts in the housing (90).
5. The heat exchanger (50) and the valve (60) are integrated in the housing (90) to eliminate an external pipe for connecting the valve (60) and the cooler (50) and thus, eliminating the number of leakage joints.
6. The module (100) is more economical due to the use of the pneumatic valve (60) as compared to prior art designs which use electrical EGR valves.
7. The valve (60) and the cooler (50) are so inclined with respect to horizontal for avoiding any possible valve sticking issue even though the valve (60) is on the hot side of the heat exchanger (50) as well to avoid any possible damage/failure of the heat exchanger (50) due to pitting thereby increasing efficiency and durability of the module (100) and hence, the life of the engine.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.
,CLAIMS:We Claim:

1. An exhaust gas recirculation module (100) for an internal combustion engine, the exhaust gas recirculation module (100) comprising:
• a housing (90) mounted directly on a cylinder head (150) of the internal
combustion engine for providing a passage for exhaust gases and high pressure coolant, the housing (90) having
a first inlet (80) configured in fluid communication with an exhaust manifold of the cylinder head (150) to allow recirculation of exhaust gases therefrom,
a second inlet (75) configured therein to allow high pressure coolant to enter therein for cooling of the exhaust gases,
a first outlet (70) configured in fluid communication with an intake manifold (140) of the cylinder head (150) to allow recirculation of cooled exhaust gases thereto through a pipe (40), the pipe (40) connecting the first outlet (70) of the housing (90) to the intake manifold (140) of the cylinder head (150), and
a second outlet (65) configured therein to allow the high pressure coolant with increased temperature after the heat exchange with the exhaust gases to flow out therefrom into the intake manifold (140);
• a valve (60) integrated into the housing (90) to receive the exhaust gases
therefrom through the first inlet (80) at a controlled flow rate;
• an actuator connected to the valve (60) to selectively open and close the valve
(60) to receive and direct the exhaust gases therefrom; and
• a heat exchanger (50) integrated into the housing (90) in such a way to have
the valve (60) located on a hot side thereof for receiving the exhaust gases at a controlled flow rate therefrom, the heat exchanger (50) adapted to cool the exhaust gases using the high pressure coolant received from the second inlet (75) for sending the cooled exhaust gases into the intake manifold (140) of the cylinder head (150) through the first outlet (70).

2. The exhaust gas recirculation module (100) as claimed in claim 1, wherein the housing (90) is made up of a material selected from any of cast iron and di-cast aluminium.

3. The exhaust gas recirculation module (100) as claimed in claim 1, wherein the valve (60) is a pneumatically controlled vacuum actuated valve integrated in the housing (90) at an inclination to horizontal.

4. The exhaust gas recirculation module (100) as claimed in claim 1, wherein the valve (60) includes a vacuum inlet (55) for actuation thereof.

5. The exhaust gas recirculation module (100) as claimed in claim 1, wherein the actuator is a pneumatic/vacuum actuator.

6. The exhaust gas recirculation module (100) as claimed in claim 1, wherein the heat exchanger (50) is a U-shape heat exchanger integrated in the housing (90) at an inclination angle of 5 degrees to the horizontal.

7. The exhaust gas recirculation module (100) as claimed in claim 1, wherein the high pressure coolant is water.