CLIAMS:1. A device (10) for exhaust gas recirculation in a naturally aspirated internal combustion (IC) engine (12), said device (10) comprising
- a valve (14) comprising a flap (16) located in proximity of the junction of an EGR path (18) and an intake path (20) of said naturally aspirated IC engine (12), said flap (16) extends into said intake path (20) such as to decrease the effective area of said intake path (20) of said naturally aspirated IC engine (12) and establish a fluid communication between said EGR path (18) and said intake path (20); and
- an actuating means (22) adapted to actuate said flap (16) of said valve (14).

2. The device (10) as claimed in claim 1, wherein said actuating means (22) is at least one chosen from a group of actuating means such as a motor, a solenoid, a hydraulic drive, a pneumatic drive and the like.

3. The device (10) as claimed in claim 1, wherein said flap (16) adapted to operated between a first position and a second position.

4. The device (10) as claimed in claim 3, wherein in said first position of said flap (16) no fluid communication exists between said EGR path (18) and said intake path (20).

5. The device (10) as claimed in claim 2, wherein in said second position of said flap (16) fluid communication exists between said EGR path (18) and said intake path (20).

6. The device (10) as claimed in claim 5, wherein in said second position of said flap (16) effective area of said intake path (20) is reduced.

7. A valve (14) for a naturally aspirated internal combustion (IC) engine, said valve (14) located in proximity of the junction of an intake path (20) and an EGR path (18) of said naturally aspirated IC engine (12), said valve (14) comprising:
a housing (24) having an inlet (26) in fluid communication with said EGR path (18) and outlet (28) in fluid communication with said intake path (20);
characterized in said valve,
a flap (16) located at said outlet (28) of said housing (24), said flap (16) adapted to be operated such that said flap (16) extends into said intake path (20) such as to decrease the effective area of said intake path (20) of said naturally aspirated IC engine (12) and establish a fluid communication between said EGR path (18) and said intake path (20).

8. A valve (14) as claimed in claim 7, wherein said flap (16) located in proximity of the junction of said intake path (20) and said EGR path (18) in a manner such that axis of rotation of said flap (16) and axis of EGR path (18) are the same.

9. A valve (14) as claimed in claim 7, wherein said flap (16) is hinged at the junction of said intake path (20) and said EGR path (18).
,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 device for exhaust gas recirculation in a naturally aspirated internal combustion engine;
[005] Figure 2a illustrates a first embodiment of the valve;
[006] Figure 2b illustrates a second embodiment of the valve;
[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 device 10 for exhaust gas recirculation in a naturally aspirated internal combustion (IC) engine 12. The device 10 comprises a valve 14 comprising a flap 16 located in proximity of the junction of an EGR path 18 and an intake path 20 of the naturally aspirated IC engine 12. The flap 16 extends into the intake path 20 such as to decrease the effective area of the intake path 20 of the naturally aspirated IC engine 12 and establish a fluid communication between said EGR path 18 and the intake path 20 and an actuating means 22 adapted to actuate the flap 16 of the valve 14.

[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 partload 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 naturally aspirated (NA) engines the turbocharged 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 are also using 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 10 comprises a valve 14.

[0011] Figure 2a and 2b illustrates a valve 14 for a naturally aspirated internal combustion (IC) engine. The valve 14 is located in proximity of the junction of an intake path 20 and an EGR path 18 of the naturally aspirated IC engine 12. The valve 14 comprises a housing 24 having an inlet 26 in fluid communication with the EGR path 18 and outlet 28 in fluid communication with the intake path 20. The valve is characterized by a flap 16 located at the outlet 28 of the housing 24. The flap 16 is adapted to be operated such that the flap 16 extends into intake path 20 such as to decrease the effective area of said intake path 20 of the naturally aspirated IC engine 12 and establish a fluid communication between the EGR path 18 and the intake path 20.
[0012] In accordance with one embodiment of the valve 14 as seen in figure 2a, the flap 16 is located in proximity of the junction of the intake path 20 and the EGR path 18 in a manner such that axis of rotation of the flap 16 and axis of EGR path 18 are the same. In accordance with another embodiment represented in figure 2b of the valve 14, the flap 16 is hinged at the junction of intake path 20 and the EGR path 18. In accordance with another embodiment of the valve 14 the inlet 26 of valve housing 24 and the outlet 28 of the valve housing has varying diameters.

[0013] The flap 16 of the valve 14 is actuated by an actuating means 22. The actuating means 22 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. For actuating the flap 16 of the valve 14 using the actuating means 22 at least one part of the actuating means 22 is in contact with the at least one part of the flap. In one embodiment wherein the actuating means 22 is a motor, the connection between the motor and the flap may be realized via a gear mechanism fitted to the motor and a rod extending from the flap 16. When the flap 16 is actuated using the actuating means 22, the flap 16 is operated as being in a first position or a second position. In the first position of the flap 16, the flap remains shut, which means there is no fluid communication between the EGR path 18 and the intake 20 of the naturally aspirated IC engine. In the second position of the flap 16, the flap opens in manner such that it extends into the intake path 20. Since the flap 16 extends into the intake path 20, there exists a fluid communication between the EGR path 18 and the intake path 20. Since the flap extends or opens into the intake path 20, the effective area of the intake path 20 reduces. Due to the throttling effect Mass flow from intake is significantly effected already with small reductions of the effective inlet area (Bernoulli’s Principle).
[0014] The working principle of the valve 14 is that the opening of the flap 16 reduces the radius and hence effective area of the intake path. 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 18 and flow into the intake path 20 and then to the engine.
[0015] The working of the device 10 and the valve 14 with reference to a naturally aspirated IC engine 12 can be explained as follows with reference to figures 3 and figure 4. For the ease of understanding we consider an embodiment of the device 10 and the valve 14, wherein the actuating means 22 of the device is a motor and the flap 16 of the valve is such that axis of the rotation of the flap 16 and the axis of the EGR path is the same. As mentioned earlier in such an embodiment the connection between the motor and the flap 16 may be realized through a gear mechanism. A shaft extending from the flap 16 would have one part of the gear mechanism and the drive shaft from the motor would have a second part of the gear mechanism. During the working of the device 10 and valve 14, then there is a need to open the flap 16, the motor would receive a signal from an electronic control unit for initiating exhaust gas recirculation. The motor is switched on and flap 16 moves from a first position to a second position. When the flap moves to a second position, it extends into the intake path 20 of the naturally aspirated IC engine. A fluid communication is established between the EGR path 18 and the intake path 20. As the flap 16 extends into the intake path 20, the radius and hence effective area of the intake path 20 is reduced. The reduction in the effective area creates a suction type pressure at the junction of the intake path 20 and the EGR path 18. Due to this pressure EGR is forcibly introduced into the intake path. 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 flap 16 can be switched to a second position ensuring exhaust gas circulation is achieved.
[0016] 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. The varying positions of the flap 16 and the different embodiment of the actuating means 22 are envisaged and lie within the scope of this disclosure. Depending on the amount of exhaust gases to be introduced into the intake path 20, there may be more than one open position of the flap 16. This may be realized by the actuating means 22 opening the flap 16 into the intake path 20 at varying degrees.