Cylinder head

Abstract

A cylinder head comprising a cavity for receiving a pre-chamber gas valve, wherein an opening extending substantially or completely around the pre-chamber gas valve forms an annular passage with a wall of the cavity, that surrounds the pre-chamber gas valve, wherein the annular passage is connected to at least one gas feed passage for supplying the pre-chamber gas valve with combustion gas, wherein the annular passage with at least one inclined gas passage is connected with the lower cavity of the pre-chamber gas valve.

Claims

1. A cylinder head comprising: a cavity for receiving a pre-chamber gas valve; a recess extending substantially or completely around the pre-chamber gas valve forming an annular passage defined by a wall of the cavity and the recess of the pre-chamber gas valve; at least one gas feed passage within the cylinder head, the at least one gas feed passage with a horizontal portion and a vertical portion with respect to a longitudinal axis of the pre-chamber gas valve, the horizontal portion connecting to the annular passage for supplying the pre-chamber gas valve with combustion gas; and at least one inclined gas passage arranged to extend from the annular passage to a lower cavity of the pre-chamber gas valve, connecting via the at least one inclined gas passage the annular passage to the lower cavity of the pre-chamber gas valve.

2. The cylinder head as set forth in claim 1, wherein an angle of the at least one inclined gas passage with respect to the longitudinal axis of the pre-chamber gas valve is between 20 and 70.

3. The cylinder head as set forth in claim 1, wherein a spark plug sleeve is arranged within the cylinder head, with the wall of the cavity defined by the spark plug sleeve.

4. The cylinder head as set forth in claim 1, wherein the wall of the cavity is defined by the cylinder head.

5. The cylinder head as set forth in claim 1, wherein between the pre-chamber gas valve and a pre-chamber or between the pre-chamber gas valve and a passage leading to a pre-chamber, is a space.

6. The cylinder head as set forth in claim 5, wherein the space is of a substantially pear-shaped configuration which narrows towards the pre-chamber.

7. The cylinder head as set forth in claim 1, wherein the pre-chamber gas valve has at least one projection with one side of the at least one projection abutting and delimiting the annular passage, and an opposite side of the at least one projection abutting a sealing means for creating a seal between the pre-chamber gas valve and the wall.

8. The cylinder head as set forth in claim 1, wherein a spark plug is arranged in the cylinder head, wherein the spark plug and the pre-chamber gas valve are arranged in a common cavity of the cylinder head.

9. The cylinder head as set forth in claim 7, wherein the spark plug and the pre-chamber gas valve are arranged in separate bores.

Description

(1) The invention is illustrated in greater detail by the Figures in which:

(2) FIGS. 1a through 1c is through is show a cylinder head with spark plug sleeve,

(3) FIGS. 2a through 2c show a spark plug sleeve for a cylinder head,

(4) FIGS. 3a through 3c show a further spark plug sleeve for a cylinder head,

(5) FIGS. 4a through 4e show details relating to the gas feed concept, and

(6) FIGS. 5a and 5b show a pre-chamber gas valve and a variant thereof.

(7) FIG. 1a is shows a cylinder head 2 with a spark plug sleeve 4 fitted into the cylinder head 2. In this embodiment a cavity 7 is formed by the spark plug sleeve 4.

(8) FIGS. 1b and 1c show two views of the spark plug sleeve 4.

(9) FIG. 1a shows a longitudinal section through the cavity 7 which accommodates a spark plug 6 (not shown) and a pre-chamber gas valve 5.

(10) The cavity 7 includes on the one hand a shaft which is concentric around the axis of symmetry S1, consisting of cylinder portions, for receiving a spark plug 6.

(11) The cavity 7 further has a bore 10 with an axis of symmetry S2 for receiving a pre-chamber gas valve 5.

(12) A passage 8 leads from the pre-chamber gas valve 5 to the pre-chamber 3. The pre-chamber 3 comprises on the one hand the actual cavity, that is to say the hollow space in which the ignition of mixture takes place. The pre-chamber 3 is of course also a physical component. In the present embodiment the pre-chamber 3 is in the form of a component separate from the spark plug sleeve 4 and is connected to the spark plug sleeve 4, for example by pressing.

(13) The spark plug 6 which is not shown for the sake of clarity is introduced into the spark plug sleeve 4 by way of the shaft concentric with the axis of symmetry S1, in such a way that it terminates flush with the pre-chamber 3 and its electrodes project into the pre-chamber 3. The pre-chamber 3 is enriched with combustion gas by the pre-chamber gas valve 5 by way of the passage 8. After ignition in the pre-chamber 3 ignited mixture passes by way of the flow transfer bores 9 into the main combustion chamber (not shown).

(14) FIG. 1b shows a plan view of FIG. 1a. It is possible to see the parallel cylindrical shafts disposed within the cavity 7 for receiving a spark plug 6 and a pre-chamber gas valve 5. The spark plug 6 is not shown, as explained with reference to FIG. 1a. It is possible to see in the pre-chamber gas valve 5 an octagon with which the pre-chamber gas valve 5 is screwed into the spark plug sleeve 4. In the present embodiment there is a largest bore diameter D1 of the cavity 7, which in a plan view circumscribes the bores for receiving the spark plug 6 and the pre-chamber gas valve 5. In other words, in this embodiment, there is a common shaft for spark plug 6 and pre-chamber gas valve 5.

(15) The center line of that largest bore of the diameter D1 is between the axes of symmetry S1 and S2. The common shaft has advantages in terms of mounting of the spark plug 6 and the pre-chamber gas valve 5, but weakens the spark plug sleeve 4 as there is only little wall thickness remaining.

(16) FIG. 1c shows a perspective view of the spark plug sleeve 4 of this embodiment.

(17) FIGS. 2a through 2c show various views of a spark plug sleeve 4 for insertion into a cylinder head 2 (not shown) in accordance with a further embodiment. Here too the cavity 7 is formed by the spark plug sleeve 4. While in the embodiment of FIGS. 1a through 1c the cavity 7 has a cylindrical portion which with its largest diameter circumscribes both the bore for receiving the spark plug and also the bore for receiving the pre-chamber gas valve 5, in the present embodiment the largest diameter of the cavity 7 no longer entirely embraces the bore of the spark plug sleeve 4. Rather, the bore 10 of the pre-chamber gas valve 5 passes through the spark plug bore 11 in the upper portion thereof, of the largest diameter. That will be particularly clearly apparent from the view in FIGS. 2b and 2c. In a plan view (FIG. 2b) therefore the bore 10 for receiving the pre-chamber gas valve 5 and the bore for receiving the spark plug 6 overlap.

(18) FIGS. 3a through 3c show a further embodiment of a spark plug sleeve 4 for insertion into a cylinder head 2 (not shown). Here too the cavity 7 is formed by the spark plug sleeve 4.

(19) Here the bore for receiving the pre-chamber gas valve 5 is also not circumscribed by a largest diameter of the cavity 7. In other words, here too the bores for receiving a spark plug 6 and for receiving the pre-chamber gas valve 5 pass through each other. In comparison with the embodiment shown in FIGS. 2a through 2c here the contour of the cavity 7 is altered. Here the contour of the cavity 7 is of such a configuration that the cylindrical bores for receiving the spark plug 6 and the pre-chamber gas valve 5 blend smoothly into each other. In other words, the sharp transitions of the embodiment of FIGS. 2a through 2c are here replaced by a smooth radius in the transition of the two bores.

(20) FIG. 4a shows a section through a spark plug sleeve 4, wherein the section was so positioned that the gas feed to the pre-chamber gas valve 5 is clearly illustrated. The section line is sketched in FIG. 4b.

(21) A gas feed passage 12 opens into an annular passage 13 which is formed between a wall 10 surrounding the pre-chamber gas valve 5 and the outside contour of the pre-chamber gas valve 5. In other words the bore 10 together with the pre-chamber gas valve 5 forms an annular passage 13 into which the gas feed passage 12 opens.

(22) From the annular passage 13 formed by the wall 10 and the pre-chamber gas valve 5, the inflowing gas is guided uniformly into the pre-chamber gas valve 5. In the embodiment illustrated here the wall 10 is again formed by the wall of the spark plug sleeve 4.

(23) FIG. 4c shows a longitudinal section through the spark plug sleeve 4. The section line can be seen from FIG. 4d. As can be seen from FIG. 4c the sectioning is here so selected that it is also possible to see the part of the gas feed passage 12, that extends parallel to the axis of symmetry S1.

(24) FIG. 4e is an isometric perspective view showing the arrangement of the pre-chamber gas valve 5 and its gas supply. The gas supply is afforded by the horizontal and the vertical portions of the gas feed passage 12.

(25) FIG. 5a shows a sectional view of a pre-chamber gas valve 5. The pre-chamber gas valve 5 can be fitted into a cavity 7 formed by a cylinder head 2 (not shown here) or into a cavity 7 formed by a spark plug sleeve 4 (not shown here). The cavity 7 is therefore an opening which is provided either in a cylinder head 2 directly or in a spark plug sleeve 4 and which can accommodate a pre-chamber gas valve 5.

(26) It is possible to clearly see the annular passage 13 formed between the wall 10 of the cavity 7 and the outside contour of the pre-chamber gas valve 5. The wall 10 can be formed either by the cylinder head 2 itself or by a spark plug sleeve 4 fitted into the cylinder head 2. That possibility was described by means of the embodiments shown in FIGS. 1 through 4.

(27) The valve needle 14 is braced against its seat by the spring 15. The cap 16 embraces the spring 15 and is connected to the valve needle 14 for example by way of a beam welding.

(28) The plug 17 closes and seals off the pre-chamber gas valve 5 upwardly. Sealing of the annular passage 13 with respect to the cavity 7 is effected radially by way of the O-rings 18. They are arranged in annular receiving means formed by the projections 19. The sealing concept of the pre-chamber gas valve 5 shown here therefore provides that sealing of the pre-chamber gas valve 5 is effected radially, that is to say by way of the outside surface of the pre-chamber gas valve 5.

(29) FIG. 5b shows a variant of FIG. 5a in which the space 23 is of a very substantially pear-shaped configuration narrowing towards the pre-chamber 3. That configuration is particularly advantageous from the fluidic point of view.

LIST OF REFERENCES USED

(30) 1 internal combustion engine 2 cylinder head 3 pre-chamber 4 spark plug sleeve 5 pre-chamber gas valve 6 spark plug 7 cavity 8 passage 9 flow transfer bore 10 wall of the cavity 7 11 spark plug bore 12 gas feed passage 13 annular passage 14 valve needle 15 valve spring 16 cap 17 plug 18 O-ring 19 projection 20 gas passage 21 lower cavity of the pre-chamber gas valve 22 upper cavity of the pre-chamber gas valve 23 space 24 valve body S1 axis of symmetry S2 axis of symmetry