CLIAMS:We Claim:
1. A valve (10) for a naturally aspirated internal combustion engine (12), said valve (10) located in proximity of the junction of an intake path (14) and an EGR path (16) of said naturally aspirated internal combustion engine (12), said valve (10) comprising;
- a housing (18) having an inlet (20) in fluid communication with said EGR path (16) and an outlet (22) in fluid communication with said intake path (14);
characterized in that
- a movable element (24) comprising a shaft (26) and a valve element (28) mounted on said shaft (26), said movable element (24) adapted to be operated between a first position and a second position;
- a valve seat (30) fitted in said housing (18) in a manner such that in said first position of said movable element (24) said valve element (28) and said valve seat (30) are engaged to each other.
2. The valve (10) as claimed in claim 1, wherein said valve (10) comprises a stopper (31) mounted on said shaft (26).
3. The valve (10) as claimed in claim 2, wherein said stopper (31) is mounted at one end of said shaft (26) in proximity with said outlet (22) of said housing (18).

4. The valve as claimed in claim 1, wherein in said second position of said movable element (24) said valve element (28) and said valve seat (30) are disengaged from each other.
5. The valve as claimed in claim 1, wherein in said second position of said movable element (24), at least a part of the said shaft (26) extends into said intake path (14) of said naturally aspirated internal combustion engine (12).
6. A device (32) for exhaust gas recirculation in a naturally aspirated internal combustion engine (12), said device (32) comprising:
a valve (10) comprising a shaft (26), said shaft (26) located in a housing (18) of said valve (10) in a manner such that one end of said shaft (26) extends outside housing (18);
an actuating means (34) in contact with said one end of said shaft (26) extending outside said housing (18).

7. The device (32) as claimed in claim 6, wherein said valve (10) is adapted to be operated between a first position and a second position.

8. The device (32) as claimed in claim 7, wherein in said second position of said valve (10), said shaft (26) extends into an intake path of said naturally aspirated internal combustion engine (12).

9. The device (32) as claimed in claim 6, wherein said actuating means (34) may be at least one actuating means chosen from a group of actuating means such as a motor, a solenoid, a hydraulic drive, pneumatic drive and the like. ,TagSPECI:Field of the invention
[001] This invention relates to a device for exhaust gas recirculation and a valve thereof.

Background of the invention
[002] US patent application numbered 20110061625 discloses a valve for an exhaust gas circulation device. The valve is a single valve element located in proximity of an exhaust gas path and an EGR path which is controlled by an actuator.

Brief description of the accompanying drawings
[003] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:
[004] Figure 1 illustrates a valve for a naturally aspirated internal combustion engine;
[005] Figure 1a illustrates a movable element of the valve represented in figure 1;
[006] Figure 2 illustrates a device for a exhaust gas recirculation in a naturally aspirated internal combustion engine;
[007] Figure 3 illustrates flow of the exhaust gases with a first position of the flap of the valve; and
[008] Figure 4 illustrates flow of exhaust gases with a second position of the flap of the valve.

Detailed description of the invention
[009] Figure 1 illustrates a valve 10 for a naturally aspirated internal combustion engine 12. The valve 10 is located in proximity of the junction of an intake path 14 and an EGR path 16 of the naturally aspirated internal combustion engine 12. The valve 10 comprises a housing 18 having an inlet 20 in fluid communication with the EGR path 16 and an outlet 22 in fluid communication with the intake path 14. The valve is characterized by a movable element 24 comprising a shaft 26 and a valve element 28 mounted on the shaft 26. The movable element 24 is adapted to be operated between a first position and a second position and a valve seat 30 fitted in the housing 18 in a manner such that in one position of the movable element 24 the valve element 28 and the valve seat 30 are engaged to each other. The valve 10 comprises a stopper 31 mounted on the shaft 26. The stopper 31 is mounted at one end of the shaft 26 in proximity with the outlet 22 of the housing 18.
[0010] Usage of Exhaust Gas Recirculation (EGR) is one of the most effective strategies to reduce NOx emissions in modern Diesel engines. EGR operation especially at part-load conditions requests a significant pressure difference in between engine outlet and air inlet. The higher exhaust outlet pressure will allow exhaust to flow from the engine outlet side to the air inlet side of the engine. An EGR-Valve in between will allow to control the flow. Due to the higher exhaust backpressure of Turbocharged (TC) engines compared to natural aspirated (NA) engines these kinds of engines allow higher EGR flow rates. Assuring a sufficient EGR flow in a naturally aspirated engine with less backpressure is challenging. Furthermore due to the limited power naturally aspirated engines are operating also during emission cycle condition under full load operation. An effective emission reduction also for full or high load operation is necessary for especially smaller naturally aspirated engines. Naturally aspirated engines also use EGR under high load conditions. Tolerances in EGR rate will have a significant impact to the soot emissions of the engine. At low load operating conditions the possibility of the exhaust gas flowing through the EGR path is limited. For forcing an increased flow of the exhaust gases through the EGR path the device 10 is used. The device 32 comprises a valve 10 as shown in figure 2.

[0011] Figure 2 illustrates a device 32 for exhaust gas recirculation in a naturally aspirated internal combustion engine 12. The device 32 comprises a valve 10 comprising a shaft 26. The shaft 26 is located in a housing 18 of the valve 10 in a manner such that one end of the shaft 26 extends outside the housing 18 and an actuating means 34 is in contact with the end of the shaft 26 which extends outside the housing 18.

[0012] The device 32 is located in the proximity of the junction of the intake path 14 and the EGR path 16. The valve 10 of the device 32 has a housing 18 having an inlet 20 and an outlet 22. The inlet 20 of the valve 10 is in fluid communication with the EGR path 16 and the outlet 22 is in fluid communication with the intake path 14. The valve 10 comprises a movable element 24 comprising a shaft 26 and a valve element 28 mounted on the shaft 26. As mentioned earlier at least a part of the shaft extends outside the housing is in contact with the actuating means 34. The actuating means 34 may be at least one actuating means chosen from a group of actuating means such as a motor, a solenoid, a hydraulic drive, pneumatic drive and the like. The connection between at least a part of the shaft 26 and the actuating means 34 may be established through a gear mechanism. During the working of the valve 10, when the actuating means 34 is actuated the valve 10 switches between a first position and a second position. In the first position of the valve 10 the movable element 24 is positioned such that the valve element 28 and the valve seat 30 are engaged to each other. In the second position of the valve 10 the movable element 24 is moved from a position such that the valve element 28 and valve seat 30 are disengaged from each other. In the first position of the valve element 28 and the valve seat, there is no fluid communication between EGR path 16 and the intake path 14 of the naturally aspirated internal combustion engine 12. Thus in the first position of the valve 10 exhaust gases from the exhaust gas path are not recirculated back to the engine 12. In the second position of the valve element 28 and the valve seat 30, a fluid communication is established between intake path 14 and the EGR path 16. In the second position of the movable element 24, at least a part of the shaft 24 extends into the intake path 14 of the naturally aspirated internal combustion engine 12. Due to the extension of the shaft into the intake path 14, the effective area of the intake path 14 is reduced. The reduction in the effective area of the intake path 14 forces the air from the EGR path 16 to enter the intake path 14.
[0013] The working principle of the valve 10 is that in the second position of the movable element 24 of the valve 10 the radius and hence effective area of the intake path 14 is reduced. The reduction in radius of the intake path leads to reduction in volume, but an increase in pressure. The reduction in volume and increase in pressure causes forced induction of the exhaust gases into the EGR path. The forced induction ensures that the exhaust gases from the exhaust path of the naturally aspirated IC engine 12, enter the EGR path 16 and flow into the intake path 14 and then to the engine.
[0014] The working of the valve 10 and the device 32 in a naturally aspirated internal combustion engine will be explained below with reference to figures 3 and 4. For ease of understanding on the device 32 and the valve 10, we consider an embodiment of the device 32 wherein the actuating means 34 is a motor. The connection between the motor and at least a part of the shaft 26 extending from the housing 18 of the valve 10 is established through a gear mechanism. One part of the gear mechanism is mounted on the shaft 26 which extends from the housing 18 and the second part of the gear mechanism is mounted on the shaft extending from the motor. During the working of the naturally aspirated internal combustion engine 12 initially the movable element 24 of the valve 10 is in a first position wherein no fluid communication exists between the intake path 14 and the EGR path 16. When it is required that the exhaust gases from the exhaust gas path be recirculated to the intake path 14, an electronic control unit sends an actuating signal to the motor 34. The motor 34 is actuated and rotary motion is imparted to the shaft extending from the motor, through the gear mechanism the rotary motion is transferred to the shaft 26 of the movable element 24 of the valve 10. When the shaft 26 rotates, the movable element 24 is moved from a first position to a second position. In the second position the valve element 28 and the valve seat are disengaged. In the second position at least a part of the shaft 26 extends into the intake path 14. The extension of the shaft 26 into the intake path 14 reduces the radius and hence effective area of the intake path. The reduction in the effective area creates a suction type pressure at the junction of the intake path 14 and the EGR path 16. Due to this pressure exhaust gas is forcibly introduced into the intake path 14. This process of forced induction of the exhaust gases ensures that even for naturally aspirated IC engines an effective exhaust gas recirculation can be achieved. Thus in any load condition of the naturally aspirated engine the movable element 24 can be switched to a second position ensuring exhaust gas circulation is achieved. When the movable element 24 moves from the first position to the second position the stopper 31 engages with a portion of the outlet 22 of the housing 18 of the valve 10. This ensures that the movement of the movable element is restricted such that the intake 14 is never completely closed.
[0015] It must be understood that the scope of the disclosure is only limited by the scope of the claims. The embodiment explained in the description above and the working example is illustrative of one embodiment and does not limit the scope of this disclosure. Varying position of the movable element 24 to reduce the effective area of the intake path 14 are envisaged and lie within the scope of this disclosure. Depending on the amount of exhaust gases to be introduced into the intake path 14, there may be different positions of the movable element 24. This may be realized by the actuating means 34 extending the shaft into the intake path 14.