JP2017106369A - Valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve device capable of precisely controlling recirculation amount of exhaust gas.SOLUTION: An EGR valve 42 provided in an EGR passage 40 for recirculating exhaust gas of an engine to control recirculation amount of the exhaust gas includes: a housing 100 having a flow passage in which the exhaust gas flows; a valve seat 110 provided in the housing 100 and having a valve hole 112; and a valve element 120 moved between a closing position for closing the valve hole 112 and an opening position for opening the valve hole 112. The valve seat 110 includes: a first inner peripheral surface 114 coming into contact with the valve element 120 located at the closing position; and a second inner peripheral surface 116 provided to be inclined to the movement direction of the valve element 120 so as to oppose to the valve element 120 when it is moved from the closing position to the opening position.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a valve device that is provided in a recirculation passage for recirculating exhaust of an engine and adjusts the recirculation amount of the exhaust.

In the vehicle, in order to reduce NO _x emissions amount to lower the combustion temperature in the cylinders of the engine, recirculation passage for recirculating part of exhaust of the engine to the intake passage is utilized. The recirculation passage is provided with an EGR valve that is a valve device for adjusting the recirculation amount of the exhaust gas.

  The EGR valve has a valve seat in which a valve hole is formed, and a valve body that is provided so as to be seated on the valve seat and opens and closes the valve hole. In this EGR valve, the recirculation amount of the exhaust gas is adjusted by adjusting the opening area through which the exhaust moves between the valve body and the valve seat.

JP 2000-73880 A

  In recent years, with the request for common parts, for example, an EGR valve used for a vehicle with a large displacement may be used for a vehicle with a small displacement. In a vehicle with a small exhaust amount, since the exhaust gas recirculation amount is small, the degree to which the valve element opens the valve hole is small. As a result, the amount of movement of the valve body for adjusting the exhaust gas recirculation amount is also small, and the exhaust gas recirculation amount cannot be finely controlled.

  Therefore, the present invention has been made in view of these points, and an object thereof is to provide a valve device capable of finely controlling the exhaust gas recirculation amount.

In one aspect of the present invention, a valve device is provided in a recirculation passage for recirculating exhaust gas from an engine and adjusts the recirculation amount of the exhaust gas, the housing including a flow path through which the exhaust flows, and the housing. A valve seat having a valve hole, and a valve body that moves between a closed position that closes the valve hole and an open position that opens the valve hole, wherein the valve seat is positioned at the closed position. The first inner peripheral surface that contacts the valve body and the valve body are inclined with respect to the moving direction of the valve body so as to face each other when the valve body moves from the closed position to the open position. A valve device having a second inner peripheral surface is provided.
According to such a valve device, the degree of increase in the area of the opening between the valve body and the valve seat becomes small with respect to the movement amount when the valve body moves to the open position. Thereby, according to the movement amount of a valve body, the passage amount of the exhaust gas which passes through an opening can be finely controlled, and as a result, the recirculation amount of exhaust gas can be finely controlled.

  In addition, the first inner peripheral surface is provided to be inclined with respect to the moving direction, and an inclination angle of the second inner peripheral surface with respect to the moving direction is an inclination angle of the first inner peripheral surface with respect to the moving direction. It is good also as being smaller than.

  The length of the second inner peripheral surface in the moving direction may be greater than the length of the first inner peripheral surface in the moving direction.

  The housing includes a housing main body provided with the first inner peripheral surface, and a detachable member detachably attached to the housing main body and provided with the second inner peripheral surface. Also good.

  According to the present invention, it is possible to provide a valve device that can finely control the recirculation amount of exhaust gas.

It is a mimetic diagram showing an example of composition of vehicles 1 to one embodiment of the present invention. 4 is a perspective view showing an example of a configuration of an EGR valve 42. FIG. It is the figure which looked at the EGR valve | bulb 42 of FIG. 2 from the lower side. It is AA sectional drawing of FIG. It is a figure for demonstrating the obstruction | occlusion position and open position of the valve body 120. FIG. It is a figure for demonstrating the EGR valve | bulb 900 which concerns on a comparative example. It is a graph for demonstrating the relationship between an opening area and the moving amount | distance of a valve body.

<Vehicle configuration>
A configuration of a vehicle 1 on which an EGR valve that is a valve device according to an embodiment of the present invention is mounted will be described with reference to FIG.

  FIG. 1 is a schematic diagram illustrating an example of the configuration of the vehicle 1. The vehicle 1 is a large vehicle such as a truck or a bus. As shown in FIG. 1, the vehicle 1 includes an engine 10, an intake passage 20, an exhaust passage 30, an EGR passage 40, and a supercharger 50.

  Here, the engine 10 is a four-cylinder diesel engine. The engine 10 generates power by burning and expanding a mixture of fuel and intake air (air). The engine 10 includes an intake manifold 11, an exhaust manifold 12, and cylinders 13a to 13d. The intake manifold 11 is a manifold connected to the intake passage 20 and branches the intake air in the intake passage 20 into four cylinders 13a to 13d. The exhaust manifold 12 is a manifold connected to the exhaust passage 30, collects exhaust exhausted from the cylinders 13 a to 13 d, and exhausts the exhaust to the exhaust passage 30. The cylinders 13a to 13d take in the intake air and exhaust the exhaust gas after combustion.

  The intake passage 20 is a passage through which intake air (air) is sucked into the cylinders 13 a to 13 d via the intake manifold 11. The intake passage 20 is provided with a compressor 52, an intercooler 23, and an intake throttle valve 24 of the supercharger 50 from the upstream side toward the downstream side. The compressor 52 compresses the intake air that passes through the compressor 52. The intercooler 23 cools the intake air that has been compressed by the compressor 52 and has risen in temperature with a coolant or the atmosphere. The intake throttle valve 24 adjusts the flow rate of intake air.

  The exhaust passage 30 is a passage for discharging exhaust collected in the exhaust manifold 12 to the outside of the vehicle. A turbine 51 of the supercharger 50 is provided in the exhaust passage 30. The turbine 51 of the supercharger 50 rotates by receiving the energy of the exhaust gas that passes through the turbine 51. The turbine 51 is connected to the compressor 52 in the intake passage 20.

  The EGR passage 40 is a recirculation passage that connects the exhaust passage 30 and the intake passage 20 and recirculates a part of the exhaust discharged from the engine 10 to the intake passage 20. The EGR passage 40 is provided with an EGR cooler 41 and an EGR valve 42. The EGR cooler 41 cools the exhaust gas in the EGR passage 40. The EGR valve 42 is a valve device that is provided on the downstream side of the EGR cooler 41 so as to be openable and closable and adjusts the recirculation amount of the exhaust gas recirculated to the intake passage 20. Details of the EGR valve 42 will be described later.

  The supercharger 50 is a device that supercharges intake air sucked into the engine 10, and here is a turbocharger that uses exhaust pressure as a power source. In the supercharger 50, the turbine 51 rotates in response to the energy of the exhaust gas that passes through, so that the compressor 52 connected to the turbine 51 rotates to compress the intake air in the intake passage 20.

  Although not shown in FIG. 1, the vehicle 1 is provided with an ECU that controls the operation of each device described above. The ECU is an electronic control unit (Electric Control Unit) including a microcomputer having a CPU, a ROM, a RAM, and the like. For example, the ECU adjusts the opening degree of the EGR valve 42 to control the exhaust gas recirculation amount in the EGR passage 40.

<Detailed configuration of EGR valve 42>
A detailed configuration of the EGR valve 42 will be described with reference to FIGS.

FIG. 2 is a perspective view showing an example of the configuration of the EGR valve 42. FIG. 3 is a view of the EGR valve 42 of FIG. 2 as viewed from below. 4 is a cross-sectional view taken along line AA in FIG. FIG. 5 is a view for explaining a closed position and an open position of the valve body 120.
As shown in FIG. 3, the EGR valve 42 includes a housing 100, a valve seat 110, and a valve body 120.

  The housing 100 forms a housing of the EGR valve 42. The housing 100 includes a flow path 102 through which exhaust flows. Here, the flow path 102 is bent at about 90 degrees, and both ends of the flow path 102 are connected to the EGR passage 40. As shown in FIG. 3, the housing 100 includes an exhaust inlet 104 and an exhaust outlet 106. The exhaust gas flowing through the EGR passage 40 flows into the flow path 102 via the inlet 104 and then flows out to the EGR passage 40 via the outlet 106. 2 to 4, the direction in which the exhaust G flows is indicated by arrows.

  The valve seat 110 is provided in the housing 100. Here, the valve seat 110 is provided in the middle of the flow path 102 (specifically, on the outflow port 106 side). The valve seat 110 is configured so that the valve body 120 can be seated. Further, the valve seat 110 includes a circular valve hole 112 through which exhaust can pass, as shown in FIG. The valve hole 112 is closed or opened by the valve body 120. When the valve hole 112 is closed, the exhaust does not pass, and when the valve hole 112 is released, the exhaust passes.

  The valve body 120 contacts (seats) or separates from the valve seat 110 to close or release the valve hole 112. The valve body 120 is movably provided, and moves between a closed position for closing the valve hole 112 shown in FIG. 5 (a) and an open position for opening the valve hole 112 shown in FIG. 5 (b). To do. By controlling the passage amount of the exhaust gas by closing or opening the valve hole 112 by the valve body 120, the recirculation amount of the exhaust gas can be controlled. As illustrated in FIG. 3, the valve body 120 includes a shaft portion 122 and a valve portion 124.

  The shaft portion 122 is connected to a motor (not shown) provided in the housing 100. The shaft part 122 is moved in the axial direction (FIG. 3) by a motor. For example, the shaft portion 122 is moved (extruded) from the closed position to the open position by the motor. Note that the movement of the shaft portion 122 from the open position to the closed position is performed by a return spring (not shown) provided in the housing 100. The return spring biases the shaft portion 122 from the open position toward the closed position.

  The valve portion 124 is provided at the tip of the shaft portion 122 and moves in the axial direction together with the shaft portion 122. The valve part 124 is formed in a disk shape. When the valve body 120 is located at the closed position, the valve portion 124 closes the valve hole 112 as shown in FIG. The valve part 124 moves toward the outflow port 106 when the valve body 120 moves from the closed position to the open position.

  By the way, in this embodiment, the valve seat 110 is configured so that the recirculation amount of the exhaust gas can be controlled more finely by the EGR valve 42. Specifically, the valve seat 110 has a first inner peripheral surface 114 and a second inner peripheral surface 116, as shown in FIGS. 5 (a) and 5 (b).

  The first inner peripheral surface 114 is a surface that contacts the valve portion 124 as shown in FIG. 5A when the valve body 120 is located at the closed position. The first inner peripheral surface 114 is formed so as to surround the valve hole 112. For this reason, when the 1st inner peripheral surface 114 is contacting the valve part 124, the valve hole 112 is obstruct | occluded. The first inner peripheral surface 114 is an inclined surface provided so as to be inclined with respect to the axial direction (FIG. 3) of the shaft portion 122 that is the moving direction of the valve body 120. Specifically, the first inner peripheral surface 114 is formed so that the inner diameter increases toward the exhaust outlet 106. The first inner peripheral surface 114 is inclined at a predetermined angle θ1 with respect to the axial direction.

  The second inner peripheral surface 116 is connected to the end of the first inner peripheral surface 114 on the outlet 106 side. The second inner peripheral surface 116 faces the valve portion 124 as shown in FIG. 5B when the valve body 120 moves from the closed position to the open position. For this reason, when the valve hole 112 is released, the amount of exhaust passing therethrough depends on the size of the area of the opening 130 between the valve portion 124 and the second inner peripheral surface 116. Providing the second inner peripheral surface 116 can prevent the area of the opening 130 between the valve seat 110 and the valve seat 110 from rapidly increasing when the valve body 120 moves from the closed position to the open position.

  The second inner peripheral surface 116 is provided to be inclined with respect to the axial direction. Specifically, the second inner peripheral surface 116 is formed so that the inner diameter increases toward the exhaust outlet 106 (FIG. 3). In such a case, as the amount of movement of the valve body 120 from the closed position increases, the area of the opening 130 between the valve portion 124 and the second inner peripheral surface 116 increases, and the amount of exhaust passing also increases.

  Further, the inclination angle of the second inner peripheral surface 116 is set so that the area of the opening 130 between the valve portion 124 and the second inner peripheral surface 116 slightly increases with respect to the movement amount of the valve body 120. Specifically, the inclination angle θ2 with respect to the moving direction of the second inner peripheral surface 116 is smaller than the inclination angle θ1 with respect to the moving direction of the first inner peripheral surface 114. Further, the length of the second inner peripheral surface 116 in the moving direction is larger than the length of the first inner peripheral surface 114 in the moving direction. Thereby, since the size of the area of the opening 130 between the valve part 124 and the 2nd internal peripheral surface 116 can be finely controlled by the movement of the valve body 120, the passage amount of exhaust gas can be controlled more finely.

Here, further explanation will be made while comparing with the comparative example shown in FIG.
FIG. 6 is a view for explaining an EGR valve 900 according to a comparative example. 6A shows a state where the valve body 920 of the EGR valve 900 is located at the closed position, and FIG. 6B shows a state where the valve body 920 is located at the open position. The valve seat 910 of the EGR valve 900 has the first inner peripheral surface 914, but does not have the second inner peripheral surface 116 of the present embodiment. For this reason, when the valve body 920 is located at the open position shown in FIG. 6B, the opening 930 between the valve portion 924 of the valve body 920 and the first inner peripheral surface 914 becomes large. For this reason, the amount of exhaust passing through the opening 930 cannot be finely controlled.

  FIG. 7 is a graph for explaining the relationship between the opening area and the amount of movement of the valve body. A broken line 810 of the graph shows the comparative example of FIG. 6, and a solid line 820 shows this embodiment. As can be seen from the graph, in the case of the present embodiment, the degree of increase in the area of the opening 130 with respect to the movement amount of the valve body 120 is smaller than in the comparative example.

  In the above description, the first inner peripheral surface 114 and the second inner peripheral surface 116 are integrally provided on the housing 100. However, the present invention is not limited to this. For example, the housing 100 may include a housing main body provided with the first inner peripheral surface 114 and an attachment / detachment member detachably attached to the housing main body and provided with the second inner peripheral surface 116. In other words, the housing 100 may be separable. In such a case, the housing 100 to which the detachable member is attached is mounted on a vehicle having a small displacement, and the housing 100 to which the detachable member is not mounted is mounted on a vehicle having a large displacement. As a result, the housing 100 can be shared for vehicles with different displacements.

<Effect in this embodiment>
According to the EGR valve 42 according to the above-described embodiment, the valve seat 110 includes the valve body 120 in addition to the first inner peripheral surface 114 that contacts the valve body 120 when the valve body 120 is located at the closed position. It has the 2nd inner peripheral surface 116 which inclines so that it may oppose, when moving from an obstruction | occlusion position to an open position.
In such a case, the degree of increase in the area of the opening 130 between the valve body 120 and the valve seat 110 becomes small with respect to the movement amount when the valve body 120 moves to the open position. As a result, the amount of exhaust passing through the opening 130 can be finely controlled according to the amount of movement of the valve body 120. As a result, the amount of exhaust gas recirculated by the EGR valve 42 can be finely controlled.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

40 EGR passage 42 EGR valve 100 Housing 110 Valve seat 112 Valve hole 114 First inner peripheral surface 116 Second inner peripheral surface 120 Valve body

Claims (4)

A valve device that is provided in a recirculation passage for recirculating the exhaust of the engine and adjusts the recirculation amount of the exhaust,
A housing including a flow path through which the exhaust flows;
A valve seat provided in the housing and having a valve hole;
A valve body that moves between a closed position for closing the valve hole and an open position for opening the valve hole;
With
The valve seat is
A first inner peripheral surface that contacts the valve body located at the closed position;
A second inner peripheral surface provided to be inclined with respect to the moving direction of the valve body so as to face when the valve body moves from the closed position to the open position;
A valve device. The first inner peripheral surface is provided to be inclined with respect to the moving direction,
An inclination angle of the second inner peripheral surface with respect to the moving direction is smaller than an inclination angle of the first inner peripheral surface with respect to the moving direction.
The valve device according to claim 1. The length in the moving direction of the second inner peripheral surface is larger than the length in the moving direction of the first inner peripheral surface,
The valve device according to claim 1 or 2. The housing is
A housing body provided with the first inner peripheral surface;
A detachable member that is detachably attached to the housing main body and provided with the second inner peripheral surface,
The valve device according to any one of claims 1 to 3.

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