GB2584708A

GB2584708A - Poppet valve

Info

Publication number: GB2584708A
Application number: GB1908455.7A
Authority: GB
Inventors: Lia Luigi; Aimasso Alberto; Mancuso Francesca; Filippo Caloiaro Mario; Ruscigno Manuel; Aimo Boot Marco
Original assignee: Eaton Intelligent Power Ltd
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2019-06-12
Filing date: 2019-06-12
Publication date: 2020-12-16
Also published as: GB201908455D0

Abstract

A hollow poppet valve 10, comprising: a valve stem 2, a valve body 4 having along a longitudinal axis a first end with a neck portion 3 to which the valve stem is coaxially arranged and having along a longitudinal axis a second end, wherein the valve body comprises a cavity 6 with a first opening towards the first end and a second opening 5 towards the second end, a valve cap 11 coaxially arranged to the valve body 4 on the second end for closing the second opening, and heat exchanging ribs 11arranged on a surface bordering the cavity 6. The ribs may be undulating in shape and formed on the valve body or cap, alternatively the ribs may form a turbulator (fig.7). The cavity may contain Sodium.

Description

Poppet valve inc invention relates to a poppet.valve, in particular a hollow poppet valve, comprising: - a valve stem.; - a valve body having a long a lor.ndinal axis a first end with a neck portion to which the valve stem is coaxially arranged and. having along a longitudinal axis a second end, wherein the valve body comprises a cavity with a first opening towards the first end and a second opening towards the second end.; - a valve cap coaxially arranged to the valve body on the second end for closing the second opening.

Such a hollow poppet valve is known from 1 2016356106. This publication describes a valve, in which a valve body is provided with a cavity opening at an axial. end. This cavity is closed by a valve cap, which. is welded to the valve body. The weld is arranged in the axial end surface of the valve. The cavity is typically filled with sodium to improve the heat exchange between the valve cap and the valve stem, such that heat from the valve head can be transferred via the valve stem into the cylinder head and the coolant flowing through the cylinder head.

The heat exchange with the sodium is however limited.

by e contact surface of the valve with the sodium.

It is an object of the invention to improve this heat ex( anae.

This object is achieved with a pov.ppet valve according to the invention, which. poppet valve is characterized by heat exchanging ribs arranged on a surface bordering the cavity.

By providing heat exchanging ribs on a surface of the poppet. valve bordering the cavity, the heat. exchanging a contact between the sodium, typically provided in the cavity, and the pogpet valve is increased. This ensures a better heat transfer from the poppet valve via the heat exchanging medium, such as sodium, provided in the cavity.

In a preferred embodiment of the poppet valve ac corerng to the invention the heat exchanging-ribs are arranged on the valve cap.

Typically, the most heat is absorbed by the valve cap and by increasing the contact with the heat. exchanging medium in the cavity, the heat can effectively be discharged to the valve stem.

In a further preferred. embodiment of the poppet valve according to the invention the heat exchanging ribs are provided by the valve cap surface bordering the cavity, which surface has in radial cross-section an undulating shape.

Preferably, the heat exchanging ribs are concentric undulations.

A valve, cap is typically made of austeniticiNisup.eralloy/martensitic material, and is manufactured by either machining or hot/cold. forging. Especially when manufactuned by hot/cold forging, an undulating shape is easily provided simply by providing the forging tools with a suitable shape.

In a further preferred embodiment of the poppet valve according to the invention, the heat exchanging ribs are arranged on the valve body.

Also a substantial amount of heat is received by the fillet part of the poppet valw2. By providing heat exchanging ribs on the valve body, the neat transfer from the valve body and. in particular the fillet portion can be increase', Preferably, the heat exchanging ribs are provided by the valve body surface bordering the cavity, which surface has in cross-section an undulating shape.

A valve body is typically made of austenitic/Ni-superallov/martensitic material. The valve body can be manufactured by hot or cold forging and further operations such as head cavity machining and stem hole drilling.

Especially with forging, providing an undulating shape at the valve body surface bordering the cavity can easily be done.

In yet another embodiment of the poppet valve accc:ling to the invention, the heat exchanging ribs are a tubulator coaxially arranged in the the neck portion of the valve body and in heat conducting contact with the valve body.

Although a tuhulator is typically used to convert laffinar flow into a turbulent flow, the tabulator arranged in a poppet valve according to the Invention typically increases the heat exchanging contact between the heat exchanging fluid in the cavity and the valve valve body. if a hollow valve stem i, p lied, then the tubulator can extend partially into this hoilow valve stem.

Theseand other features of the invention will be elucidated in conjunction with the accompanying drawings.

Figure 1 shows a cross sectional view of a hollow

poppet -Talve according to the prior art.

Figure 2 shows a cross sectional view of a first embodiment of a hollow poppet valve according to the invention.

Figures show cross sectional views or a second to a fifth eMbodimeht of a hollow poppet valve accordina to the invention.

Figure 4 shows a cross sectional view of a sixth embodiment of a hollow poppet valve according to the nention.

Figure 1 shows a. cross sectiona] -Hew of a hollow pci.opr,t valve 1 according to the prior art. The poppet valve 1 has a valve stem 2 connected to the neck portion. 3 at the first end of the valve body 3, 4. At the second end 4 of the valve body 3, 4, an opening 5 is provided, which is closed a valve cap 6. A cavity 6 is provided in the poppet valve 1, which is filled with a heat transferring fluid, such as sodium.

Fignxe 2 shows a first embodiment 10 of a poppet valve according to the invention_ Parts of the poppet valve 10 corresponding to the prior art poppet valve I are provided. witjn. tho same reference signs.

In this first embodiment 10 of the invention, a different valve cap 11 is arranged on the opening 5 of the valve boyy 3, 4. The valve cap 11 has heat exchanging ribs in the form of an undulating surface lc' bordering the cavity 6. Due to the wave shape, the area being in contact with heat transferring fluid is increased in respect to the prior art flat valve cap 6.

Figure 31k shows a. second embodiment 20 of the invention. The valve cap 21 has an undulating surface 22, wherein the number of crests is larger compared to the first embodiment 10 further increasing the area of the valve cap 21 being in contact with the heat transferring fluid in the cavity 6.

Figure 3B shows a third embodiment 30 of the iS vention. In this embodiment 30 the nuirber of crests of the undulating. surface 32 of the valve cap 31:LS even further increased such that the contact area is, increased even further.

Figure 30 shows a fourth embodiment 40 of the invention. The poppet valve 40 has a valve body 41 with a cavity 42, which is filled with a heat transferring fluid, such as sodium-The open end 43 of the valve body 41 is closed with a. valve cap 44. Heat exchanging ribs are provided both on the valve body surface 45 bordering the cavity 42 and the valve cap surface 46 bordering the cavity 42.

Figure 3D shows a fifth embodiment 50 of the invent ion, which is variant of the embodiment 40 shown In figure 3C. Corresponding parts are provided with the same reference numbers. The valve:body 41 is closed by a valve cap 51, which has an undulating surface 52 bordering the cavity 42. This undulating surface 52 has an increased number of crests increasing the contact surface with the heat exchang'fla fluid, compared to the eoldamet 40 as shown in figure 3C.

Figure 4 shows a sixth. embodiment 60 of a poppet valve according to the invention. the poppet valve 60 has a valve stem 61 connected to the neck polLion 62 on the first end of the valve body 62, . On the second end 63 of the valve -body 62, 63, an opening 54 is provided towards a cavity 15 57. This opening 64 is closed by a valve cap 65, which has an undulating surface 66 bordering the cavity 67 to increase the contact area with the heat exchanging fluid in the cavity 67. The surface 68 of the valve body 63 bordering the cavity 67 is also undulating to increase the contact surface. 20 Furthermore, a turbulator 69 is arranged in the cylindrical part of the cavity 67 to further increase the contact area between the heat exchanging fluid in the cavity 67 and the poppet valve 60.

Claims

Claims 1. Poppet valve (10; 20; 30; 40; 50; 60), in particular a hollow poppet valve, comprising: - a valve stem (2; 61); - a valve body (3, 4; 41; 62, 63) havh.na along a longitudinal axis a first end with a neck portion (8* 62) to which the valve stem 63) is coaxially arranged and having along a longitudinal axis a second end (4; 41; 63), wherein.the valve body-(3, 4; 41; 62, 63) comprises a cavity 6; 42; 67) with a first opening towards the first end and a second opening (5; 43; 641 towards the second end (4; 41; 63); - a valve cap (11; 21; 31; 44; 51; 65) coaxially arrange," to the valve body (3, 4; 41; 62, 63) on the second 15 end (4; 41; 63) for closing the second opening 8. 43; 64), characterized by heat exchangina ribs (12; 22; 32; 45, 46; 45, 52; 66, 68, 69) arranged on a surface bordering the cavity (6; 42; 67).
2. Poppet valve (10; 20; 90; 40; 50; 60) according to claim 1, wherein the heat exchanging ribs (12; 22; 32; 46; 52; 66) are arranged on the valve cap (1 21; 31; 44; 51; 65).
3. Poppet valve (10; 2)); 30; 40; 50; 60) acco.ruing to claim 2, wherein the heat exchanging ribs (12; 22; 32; 46; 52; 66) are provided by the valve cap surface (12; 22; 32; 46; 52; 66) bordering the cavity (6; 42; 67), which surface (12; 22; 32; 46; 52; 66) has in radial cross-section an undulating shape.
4. Poppet. valve (10; 20; 30; 40; 50 60) according to claim 3, wherein the -eat exchanginb ribs)12; 22; 39-46; 52; 66) are concentric undulations.
5. Poppet valve (40; 50; 60) according to any of the preceding claims, wherein the heat exchanging ribs (45; 68) are arranged. on the valve body (41; 62, 63).
6. Poppet valve (40; 50; 60) according to claim wherein the heat exchanging ribs (45; 68) are provided by the valve body surface (45; 68) bordering the cavity (42; 67), wrdch surface (45; 68) has in cross-section an undulating shape.
7. Poppet valve (60) according to any of the preceding claims, wherein the heat exchanging rHhs (69) are a tubuiator (69) coaxHally arranged In the the neck portion (62) of the valve body 62, 63) and in heat conducting contact with the valve body (62, 63).