CLIAMS:We Claim,
1. An EGR valve operable to circulate exhaust gas to an intake manifold of an engine, said EGR valve comprising:
a valve body (205);
a sphere (210) comprising a hole (225) at centre of said sphere, said sphere fixed to said valve body (205) at one end (215) and adapted to rotate within said valve body (205), wherein rotation of said sphere (210) operates said EGR valve between an open position and closed position; and
a rotary disc (230) connected to said sphere (210) using a pin (235), wherein said rotary disc (230) is adapted to rotate said sphere (210).

2. An exhaust gas recirculation (EGR) system for a vehicle comprising:
an EGR valve (105) operable to circulate exhaust gas to an intake manifold of an engine of said vehicle;
characterized in that; and
a linkage assembly (130) in contact with an accelerator pedal (110), a control lever throttle (170) and a rack (140) that is in contact with said EGR valve (105), wherein said linkage assembly (130) is adapted to operate said EGR valve (105).

3. The EGR system as claimed in claim 1, wherein said linkage assembly comprises:
a spring (130a) comprising a first end and a second end, wherein said first end is connected to said accelerator pedal (110) of said vehicle;
a triangular plate (130b) comprising a first edge, a second edge and a third edge, wherein said first edge of said triangular plate (130b) is in contact with said second end of said spring (130a) and second edge of said triangular plate (130b) is in contact with said control lever throttle (170) of a fuel pump assembly (115); and
a linkage element (130c) comprising a first end, a second end and a third end, wherein said first end of said linkage element is in contact with said third edge of said triangular plate (130b), said second end of said linkage element (130c) is in contact with said second end of said spring (130a) and said first edge of said triangular plate (130b) and said third end of said linkage element (130c) is in contact with said rack (140).
,TagSPECI:The following specification particularly describes the invention and the manner in which it is to be performed.

Field of the invention
[001] This invention relates to an exhaust gas recirculation (EGR) system.

Background of the invention
[002] Exhaust gas recirculation (EGR) in which exhaust gases are re-circulated back into an intake manifold of an engine is a known method for reducing Nox emission for meeting emission norms. An EGR system comprises an EGR valve that regulates the amount of exhaust gases that are re-circulated back into the intake manifold based on a plurality of engine operating conditions.
[003] Conventionally, an engine control unit (ECU) enables regulation of the EGR valve based on engine operating conditions. The ECU generally stores the percentage opening of the EGR valve for different engine operating conditions and further controls the EGR valve based on the engine operating condition. However, use of the ECU for regulating the EGR valve is expensive and hence a cost effective technique for controlling the EGR valve is required.

Brief description of the accompanying drawings
[004] Figure 1 illustrates an exhaust gas recirculation (EGR) valve, in accordance with one embodiment; and
[005] Figure 2 illustrates an exhaust gas recirculation (EGR) system, in accordance with one embodiment.
Detailed description
[006] Figure 1 illustrates an exhaust gas recirculation (EGR) valve 105, in accordance with one embodiment.
[007] The EGR valve comprises a valve body 205, a sphere 210, comprising a hole 225 at centre, fixed to said valve body 205 at one end 215. The sphere 205 is adapted to rotate within the valve body 205, wherein rotation of the sphere 210 operates said EGR valve between an open position and closed position. The EGR valve also comprises a rotary disc 230 connected to the sphere 210 using a pin 235, wherein the rotary disc 230 is adapted to rotate said sphere 210.
[008] A rack 140 as shown in Figure 2 is in contact with the rotary disc 230. When the rack 140 moves in the direction of the arrow 160 in Figure 1, the rotary disc 230 begins to rotate in clockwise direction, due to rack and pinion mechanism, as indicated by the arrow 260 in Figure 2. The rotation of the rotary disc 230 rotates the sphere 210 in the same direction as the rotary disc 230, because the rotary disc 230 is connected to the sphere 210 through the pin 235. Similarly, when the rack 140 moves in the direction opposite to the arrow 160, the rotary disc 230 rotates in the anticlockwise direction thereby rotating the sphere in the anticlockwise direction.
[009] Rotation of the sphere 210 enables the EGR valve to operate between an open position and closed position. During open position, the hole 225, within the sphere 210, is parallel to flow of exhaust gas in an EGR path 250. Hence, the exhaust gas is enabled to flow, along the hole 225, into intake manifold of an engine. When the EGR valve is in the closed position, the hole 225 is perpendicular to the flow of the exhaust gas in the EGR path 250. Hence the exhaust gas is blocked from flowing, along the hole 225, into intake manifold of an engine.
[0010] Figure 2 illustrates an exhaust gas recirculation (EGR) system for a vehicle, in accordance with one embodiment.
[0011] The exhaust gas recirculation (EGR) system comprises an EGR valve 105 operable to circulate exhaust gas to an intake manifold of an engine. The EGR system is characterized by a linkage assembly in contact with an accelerator pedal 110, a fuel pump assembly 115 and a rack 140 that is in contact with the EGR valve 105. The linkage assembly is adapted to operate the EGR valve 105.
[0012] Referring to Figure 2, the linkage assembly is connected to the accelerator pedal 110 and the control lever throttle 170 of the fuel pump assembly 115.
[0013] The linkage assembly comprises a spring 130a. The spring 130a comprises a first end and a second end. The first end of the spring 130a is connected to the accelerator pedal 110 of the vehicle. The linkage assembly 130 also comprises a triangular plate 130b comprising a first edge, a second edge and a third edge. The first edge of the triangular plate 130b is in contact with the second end of the spring 130a and the second edge of the triangular plate 130b is in contact with the control lever throttle 170 of the fuel pump assembly 115. The linkage assembly 130 further comprises a linkage element 130c comprising a first end, a second end and a third end. In one example, the linkage element 130c is a Y-rod. The first end of the linkage element 130c is in contact with the third edge of the triangular plate 130b. The second end of the linkage element 130c is in contact with the second end of the spring 130a, and the first edge of the triangular plate 130b. The third end of the linkage element 130c is in contact with the rack 140. The rack 140 is adapted to slide on a rail 125. The rack 140 is in contact with the EGR valve 105.
[0014] The first edge of the triangular plate 130b is in contact with the second end of the spring 130a through a pivotal joint. The second edge of the triangular plate 130b is fixed to the control lever throttle 170 through a fixed joint.
[0015] In one working example, a user presses the accelerator pedal 110. For easier understanding of one embodiment of the EGR system, the spring 130a used is an expansion spring. When the accelerator pedal is pressed, the spring 130a undergoes expansion in the direction of the arrow 150.
[0016] Expansion of the spring 130a moves the triangular plate 130b in the same direction as the arrow 150. Movement of the triangular plate 130b moves the control lever throttle 170 of the fuel pump assembly 115 in the same direction as the arrow 150. Such movement of the control lever throttle 170, increases fuel injection quantity so that the demand placed by the user is met.
[0017] The movement of the triangular plate 130b causes the linkage element to move the rack 140, on the rail 125, in the direction of the arrow 160. Such movement of the rack 140 controls opening of the EGR valve 105. Working of the EGR valve 105 is explained in detail in conjunction with Figure 1.
[0018] Similarly, when the user releases the accelerator pedal 110, the spring 130a returns to its original state in the direction opposite to the arrow 150. Such movement of the spring 130a causes the triangular plate 130b to move in the direction opposite to the arrow 150 thereby moving the control lever throttle 170 in the same direction. Such movement of the control lever throttle 170 decreases the fuel injection quantity.
[0019] The movement of the triangular plate 130b in the direction opposite to the arrow 150 causes the linkage element to move the rack 140 in the direction opposite to the arrow 160. Such movement of the rack 140 controls closure of the EGR valve 105. Hence by using such linkage assembly, mechanical way of controlling the EGR valve is achieved.
[0020] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to type of the EGR valve, direction of rotation of the circular disc, type of spring either expansion spring or compression spring and elements included in the linkage assembly are envisaged and form a part of this invention. The scope of the invention is only limited by the claims.