Claims:We Claim:
1. A valve assembly (10) for exhaust gas recirculation, comprising:
a valve body (110) having a valve seat (115); and
a valve poppet (105) arranged for moving linearly along an axis (120) of the valve body (110) between an open position and a closed position of an inlet (125) of the valve body (110);
characterized in that:
at least one perforation (130) disposed in the valve poppet (105).

2. The valve assembly (10) for exhaust gas recirculation as claimed in claim 1, wherein the at least one perforation (130) is a circle.

3. The valve assembly (10) for exhaust gas recirculation as claimed in claim 1, wherein the at least one perforation (130) is an arc.

4. A valve assembly (20) for exhaust gas recirculation, comprising:
a valve body (210) having a valve seat (215); and
a valve poppet (205) arranged for moving linearly along an axis (220) of the valve body (210) between an open position and a closed position of an inlet (225) of the valve body (210);
characterized in that:
a diameter of the valve poppet (205) is lesser than a diameter of the valve seat (215). , Description:FIELD OF THE INVENTION
[0001] The invention relates to a valve assembly for exhaust gas recirculation.

BACKGROUND OF THE INVENTION
[0002] Exhaust gas recirculation is commonly carried out in automobile engines to reduce the peak temperature achieved during combustion, to reduce thereby the NOx emissions in the exhaust gases. This is achieved by pumping a part of the exhaust gas from the engine exhaust through an exhaust gas recirculation valve to the engine cylinder. DE1921303 describes a solenoid based exhaust gas recirculation valve, in which the exhaust gas enters the valve axially and exits radially. The valve has a ring with slots of different sizes for the radial egress of the exhaust gas. The rotation of the ring controls the output of the exhaust gas.

BRIEF DESCRIPTION OF DRAWINGS
[0003] Embodiments of this disclosure are explained in principle below with reference to the drawings. The drawings are:
[0004] FIGURE 1a illustrates a first arrangement of a valve assembly for exhaust gas recirculation in a first position of a valve poppet
[0005] FIGURE 1b illustrates the first arrangement of the valve assembly in a second position of the valve poppet
[0006] FIGURE 2a illustrates a second arrangement of a valve assembly for exhaust gas recirculation in a first position of a valve poppet
[0007] FIGURE 2b illustrates the second arrangement of the valve assembly in a second position of the valve poppet

DETAILED DESCRIPTION
[0008] FIGURE 1a illustrates a first arrangement of a valve assembly 10 for exhaust gas recirculation in a first position of a valve poppet 105. The valve assembly 10 for exhaust gas recirculation comprises a valve body 110 having a valve seat 115. The valve assembly further comprises the valve poppet 105 arranged for moving linearly along an axis 120 of the valve body 110 between an open position and a closed position of an inlet 125 of the valve body 110. The valve assembly 10 further comprises at least one perforation 130 disposed in the valve poppet 105.
[0009] The at least one perforation 130 can be a circle. In other words, the at least one perforation can have a circular profile. Alternatively, the at least one perforation 130 can be an arc. In other words, the at least one perforation can have an arcuate profile. In the case of the at least one projection 130 being an arc, the arc can be concentric to a circumference of the valve poppet 105. Alternatively, the at least one perforation 130 can be of any other shape as well, such as a polygon.
[0010] As indicated above, the at least one perforation 130 can be one, two, three or more perforations in the valve poppet 105. In the case of more than one perforation, the perforations can be disposed symmetrically or asymmetrically as well.
[0011] The working of the valve assembly 10 for exhaust gas recirculation is described hereinafter. FIGURE 1b illustrates the first arrangement of the valve assembly 10 for exhaust gas recirculation in a second position of the valve poppet 105. In the first position as illustrated in FIGURE 1a, the valve poppet 105 is away from the inlet 125, thus representing the open position of the inlet 125 of the valve body 110. In the second position as illustrated in FIGURE 1b, the valve poppet 105 is disposed against the valve seat 115, thus representing the closed position of the inlet 125 of the valve body 110. The linear movement of the valve poppet 105 between the open position and the closed position of the inlet 125 is understood by a person of ordinary skill in the art.
[0012] In the first position or the open position of the inlet 125, the exhaust gas from the exhaust system flows through the inlet 125 into the valve body 110 to be fed into an engine cylinder (not shown in FIGURES). The valve poppet 105 is held in the open position usually during low load condition to maximize the flow of exhaust gas into the engine cylinder to reduce NOx emissions. In the second position or the closed position of the inlet 125, the exhaust gas from the exhaust system flows through the at least one perforation 130 into the valve body 110 to be fed into the engine cylinder. The valve poppet 105 is held in the closed position usually during full load condition. The advantage of the at least one perforation 130 is that it allows flow of exhaust gas in the closed position of the inlet 125, so that a minimal flow of exhaust gas is available even during full load condition, for reduction of NOx emissions in the exhaust.
[0013] The number of perforations 130 in the valve poppet 105 is dependent on the amount of exhaust gas flow required during full load conditions. For example, on a relative scale, a very minimal flow of exhaust gas is effected by having a single perforation. On the same scale, a large amount of flow of exhaust gas is effected by having more than one perforation. The size of the perforation can also influence the quantity of exhaust gas flow.
[0014] FIGURE 2a illustrates a second arrangement of a valve assembly 20 for exhaust gas recirculation in a first position of a valve poppet 205. The valve assembly 20 for exhaust gas recirculation comprises a valve body 210 having a valve seat 215. The valve assembly 20 further comprises the valve poppet 205 arranged for moving linearly along an axis 220 of the valve body 210 between an open position and a closed position of an inlet 225 of the valve body 210. Further, the valve assembly 20 is such that a diameter of the valve poppet 205 is lesser than a diameter of the valve seat 215.
[0015] The working of the valve assembly 20 for exhaust gas recirculation is described hereinafter. FIGURE 2b illustrates the second arrangement of the valve assembly 20 for exhaust gas recirculation in a second position of the valve poppet 205. In the first position as illustrated in FIGURE 2a, the valve poppet 205 is away from the inlet 225, thus representing the open position of the inlet 225 of the valve body 210. In the second position as illustrated in FIGURE 2b, the valve poppet 205 is disposed proximal to and within the valve seat 215, thus representing the closed position of the inlet 225 of the valve body 210. The linear movement of the valve poppet 205 between the open position and the closed position of the inlet 225 is understood by a person of ordinary skill in the art.
[0016] In the open position of the inlet 225, the exhaust gas from the exhaust system flows through the inlet 225 into the valve body 210 to be fed into an engine cylinder (not shown in FIGURES). In the second position or the closed position of the inlet 225, the difference in diameter between the valve poppet 205 and the valve seat 215 creates a passage or a clearance around a periphery of the valve poppet 205 for the exhaust gas to flow into the valve body 210. Therefore, the advantage of the diameter of the valve poppet 205 being lesser than the diameter of the valve seat 215 is that it allows flow of exhaust gas into the valve body 210 even in the closed position of the inlet 125.
[0017] Another advantage of the second arrangement is that wear and tear of the valve seat 215 and the valve poppet 205 is reduced, as there is no contact between them.
[0018] It is to be understood that the foregoing description is intended to be purely illustrative of the principles of the disclosed techniques, rather than exhaustive thereof, and that changes and variations will be apparent to those skilled in the art, and that the present invention is not intended to be limited other than as expressly set forth in the following claims.