CN110709596B

CN110709596B - Cylinder head with valve seat ring cooling mechanism

Info

Publication number: CN110709596B
Application number: CN201880036379.8A
Authority: CN
Inventors: A·泽尔克; R·珀斯彻尔
Original assignee: AVL List GmbH
Current assignee: AVL List GmbH
Priority date: 2017-06-02
Filing date: 2018-05-30
Publication date: 2022-06-07
Anticipated expiration: 2038-05-30
Also published as: AT519991B1; CN110709596A; DE102017219646A1; AT519991A1; JP2020521914A; WO2018218268A1

Abstract

The invention relates to a cylinder head (1) for an internal combustion engine having at least one cylinder, having at least one valve seat ring (5) for a poppet valve, wherein the valve seat ring (5) is provided with an annular cooling channel (6, 6 ') which extends at least partially around the valve seat at least between at least one inlet opening (70,70 ') of an inlet channel (7, 7 ') and at least one outlet opening (80, 80 ') of an outlet channel (8, 8 '), wherein the inlet channel (7, 7 ') and the outlet channel (8, 8 ') are arranged on the same side of the cylinder. For better cooling of the valve seat and simpler machining, the inlet channel (7, 7 ') opens tangentially into the annular cooling channel (6, 6') via an inlet opening (70,70 '), and the outlet channel (8, 8') branches off tangentially from the annular cooling channel (6, 6 ') via an outlet opening (80, 80').

Description

Cylinder head with valve seat ring cooling mechanism

Technical Field

The invention relates to a cylinder head for an internal combustion engine having at least one cylinder, having at least one valve seat ring for a lift valve, wherein the valve seat ring is provided with an annular cooling channel which extends at least partially around the valve seat at least between at least one inlet opening of an inlet channel and at least one outlet opening of an outlet channel, wherein the inlet channel and the outlet channel are arranged on the same side of the cylinder.

Background

High-power internal combustion engines of today have regions which are subjected to high thermal loads, for example in the region of the exhaust valve bridge between the exhaust valve seats. Said region is threatened especially with regard to thermal deformations and thus more severe valve wear.

To address this problem, the valve seat is surrounded by a surrounding cooling passage, i.e., a valve seat ring cooling mechanism, wherein a coolant flow is created around the valve seat between the inlet and the outlet.

AT 513262B 1 of the applicant shows a solution where the inlet and outlet are formed on the same cylinder side and the valve seat is circulated over an angular range of AT least 280 °. The "short-circuit flow" occurring between the inlet and the outlet is limited by a throttle point, so that on the one hand uncooled thermal bridges are prevented in the short-circuit flow region and local overheating and thermal stresses occur, and on the other hand the majority of the coolant flows along a lengthy path around the valve seat. The disadvantage of this solution is, in particular, the design of the inlet and outlet ducts, which are designed to run parallel and meet the valve seat ring cooling in the radial direction, as a result of which flow-blocking positions and disturbed inlet flows occur. The design of the choke point during machining also implies additional costs.

The AT 513746B 1 of the applicant thus provides for a plurality of inlets to be provided, which are opposed by outlets extending towards the centre of the cylinder and in particular in the direction of the injectors provided there. These inlets are now arranged asymmetrically with respect to a meridian plane of the valve seat ring. As a result, an asymmetrical flow occurs in the valve seat ring, so that the regions subjected to high thermal loads can be cooled particularly efficiently. This is disadvantageous, inter alia, in the case of inadequate short-circuit flow between the inlets and, particularly in the case of large engines, in the case of strength losses which occur as a result of the outlet openings in the injector region.

Disclosure of Invention

The object of the invention is therefore to avoid the above-mentioned problems of the prior art and to achieve a more uniform cooling of the valve seat ring and to reduce the valve wear.

According to the invention, this object is achieved by a cylinder head of the type mentioned in the introduction by: the inlet passage preferably opens into the annular cooling passage substantially tangentially via the inlet opening, an annular flow path (i.e. a lengthy annular flow area of the valve seat annular cooling passage between the inlet opening and the outlet opening) extends from the inlet opening over an angular range of 195 ° to 345 °, and the outlet passage branches off from the annular cooling passage via the outlet opening over an angular range between the tangential direction and the radial direction.

In other words, the annular cooling channel of the valve seat ring receives coolant as well as discharges coolant from the same cylinder side, wherein the inlet and outlet ducts flow around the valve seat ring over an angular range of 195 ° to 345 °. The angular range is absolute regardless of whether the valve seat ring is flowed clockwise or counterclockwise.

By the substantially tangential inflow of the coolant, a reduced pressure loss and a cross section as large as possible at the junction of the inflow channel and the annular cooling channel are ensured. By the orientation of the flow discharge channels according to the invention, an adjustment of the flow conditions within the annular cooling channel is allowed.

In one variant of the invention, the annular cooling channel extends completely around the valve seat ring, and the circulation path extends in the flow direction between the inlet aperture and the outlet aperture, while the short-circuit path extends between the outlet aperture and the inlet aperture. Thereby allowing complete circulation and cooling of the valve seat ring.

By means of the invention, a more efficient cooling of the region of the valve seat ring subjected to high thermal loads can be achieved, since the inflow and outflow is done with a weak pressure loss. For this reason, only a small bypass short-circuit flow is also formed at the short communication between the inlet opening and the outlet opening, without the need for additional measures for suppressing this short-circuit flow, which measures, however, generally have the disadvantage that the additional material causes a very local overheating. By means of the selected orientation of the discharge channel between the tangential and radial directions, the coolant flow in the bypass path can be matched to the respective use of the cylinder head and sufficient cooling of this region is achieved.

At the same time, the production is significantly simplified, since, unlike prior art solutions, standard machining methods, such as drilling of the inlet and outlet channels, are used, without requiring complex machining operations, such as milling in the cylinder head.

To this end, the invention allows optimal cooling of the valve seat at minimal manufacturing costs.

In one variant of the invention, the longitudinal central axis of the inlet duct and/or the longitudinal central axis of the outlet duct extend tangentially to the inner duct wall of the annular cooling duct of the valve seat. For this purpose, a pressure-optimized inflow and outflow can be achieved and turbulence can be reduced or completely prevented.

In order to achieve a very simple manufacture of the cylinder head according to the invention, the inlet channel and the outlet channel extend in a common first plane. For this purpose, the drill does not have to be moved and recalibrated in a complicated manner, for example during drilling. At the same time, only a very small material thickness is influenced by the passage in the direction along the longitudinal axis of the cylinder.

In one variant of the invention, the inlet channel extends in a first plane and the outlet channel extends in a second plane. The first plane then has a different course than the second plane. This makes it possible to impart an additional direction to the cooling flow.

Advantageously, the first plane runs parallel to the second plane. This also ensures a simpler machining, since, for example, fewer calibration steps are required during drilling.

When the first plane and/or the second plane are parallel to the cylinder head sealing plane, a good utilization of the available space not only in the cylinder head but also during machining can be achieved.

In a further variant of the invention, at least the drain is connected to the cylinder head cooling jacket. By applying the pressure stages to the inlet channel and the cylinder head cooling jacket, an advantageous flow process can thereby be achieved in a simple manner. Top-down cooling can be achieved, as well as cooling from the cylinder block to the cylinder head.

When at least two poppet valves with two corresponding valve bores are provided in the cylinder head, good cooling of the regions subjected to high thermal loads is ensured in the case of an inlet channel arranged on the side of the valve seat facing the valve bridge between the valve bores. The same situation can be obtained in the following cases: two outlet valves with corresponding outlet valve openings and two inlet valves with corresponding inlet valve openings are provided and the "inlet flow duct of the annular cooling duct of the valve seat ring of at least the outlet valve openings" is arranged on the side of the valve seat ring facing the outlet valve bridge.

Drawings

Further details, features and advantages of the invention result from the following description of an embodiment which is shown by way of illustration and not of limitation, wherein:

FIG. 1 shows a horizontal cross-sectional top view of the cylinder head along line I-I in FIG. 7;

FIG. 2 shows a partial side view of the cylinder head of FIG. 1;

FIG. 3 shows a combustion chamber side plan view partially in horizontal cross section of the cylinder head along line III-III in FIG. 2;

figure 4 shows a part of a vertical section of the cylinder head along the line IV-IV in figure 1;

FIG. 5 shows a portion of a vertical cross-section of the cylinder head along line V-V in FIG. 1;

FIG. 6 shows a portion of a vertical cross-section of the cylinder head along line VI-VI in FIG. 1;

figure 7 shows a part of a vertical section of the cylinder head along the line VII-VII in figure 1; and

fig. 8 shows a partial schematic illustration of a combustion chamber-side plan view of a horizontal section of the cylinder head according to fig. 3.

Detailed Description

In the following figures, like parts are designated with like reference numerals for the sake of overview.

These figures show in part in the exemplary embodiment shown a cylinder head 1 for at least one cylinder of an internal combustion engine. According to the representation in fig. 1, the cylinder head is provided with two inlet valves and two outlet valves, which are designed as lift valves, in which the

outlet valve openings

2a, 2b and

inlet valve openings

3a, 3b, sometimes also with corresponding valve axes, are shown for the respective valves. Of course, the invention may also be used in cylinders with a small number of valves. In the center of the cylinder, a further opening is provided, for example as a central opening 4 for the injector.

At least each exhaust valve is provided with a valve seat ring 5 in the cylinder head 1, e.g. pressed or glued into the cylinder head, as shown in fig. 4-7. The valve seat ring 5 pressed or glued into the cylinder head 1 is surrounded by an

annular cooling channel

6, 6 ' for the coolant, which extends at least partially around the valve seat at least between the (valve-side) inlet opening 70,70 ' of one inlet channel 7, 7 ' and the (valve-side) outlet opening 80,80 ' of one outlet channel 8, 8 '. The

cooling channels

6, 6' may now extend completely within the valve seat ring 5 or, as in the embodiment shown, be formed partly into the cylinder head 1, partly within the valve seat ring 5. The

cooling channels

6, 6' may also be formed completely within the cylinder head 1.

The coolant is fed from outside the cylinder/cylinder head 1 via the inlet channel 7 '(fig. 4), enters the annular cooling channel 6' via the inlet opening 70 '(fig. 5) and flows out of the cooling channel 6' at the outlet opening 80 '(fig. 6) to the outlet channel 8' (fig. 7), from where it continues to flow. In the embodiment shown, the

annular cooling channels

6, 6' extend completely around the valve seat ring 5. There is an annular flow path 90, 90 ' in which the coolant flows along a lengthy path through the

annular cooling channel

6, 6 ' and a short-circuit path 91,91 ' which serves as the shortest communication between the inlet opening 70,70 ' and the outlet opening 80,80 '. The inlet channels 7, 7 'and the outlet channels 8, 8' are formed, for example, by bores which extend from one side of the cylinder head 1, as shown in fig. 2. Advantageously, the inlet channels 7, 7 'and the outlet channels 8, 8' are arranged on the same side of the cylinder, in this case on the outlet side.

When the central angle alpha (fig. 1) of the valve seat ring 5 between the inlet aperture 70 and the outlet aperture 80 is less than 180 deg., preferably less than 100 deg., a balanced condition between the circulation path 90, 90 'and the short-circuit path 91, 91' is obtained, whereby a good circulation and cooling is achieved. The central angle α is the angle between the valve seat ring center 50 and the radial line between the inlet channel 7 and the outlet channel 8, in particular the point at which the longitudinal center axis of the inlet channel (input longitudinal center axis 77) or of the outlet channel (output longitudinal center axis 88) meets the annular cooling duct 6 or its outer lateral surface 61. The lengthy area of the annular cooling passage between the inlet aperture 70,70 'and the outlet aperture 80, 80' around which the coolant circulates, and thus the area of the circulation path 90, extends through an angular range of "360 ° - α" around the valve seat ring 5. According to the invention, this angle range is between 195 ° and 345 °. It has been shown that this angular range of the circulation paths 90, 90' can be used to achieve optimum heat dissipation from the thermally critical areas of the cylinder head 1.

That is, in the illustrated embodiment, a short-circuit flow between the two orifices 70,70 ', 80' occurs on the short-circuit path 91,91 'on the one hand, and a cooling flow around the valve seat along a lengthy path occurs on the circulation path 90, 90' on the other hand.

As is shown in particular in fig. 3, the inlet channels 7, 7 'open tangentially into the

annular cooling channels

6, 6' via the inlet openings 70 in the embodiment shown. By tangential within this context is meant that, within the machining tolerances, the inlet flow channels 7, 7 ', the outlet flow channels 8, 8 ' and the

annular cooling channels

6, 6 ' intersect at a point. That is to say, for example, the side of the inlet channel 7, 7 'and the outlet channel 8, 8', which side is "remote" from the valve axis of the respective valve seat or the valve

seat ring center

50, 50 '", intersects the side of the

annular cooling duct

6, 6', which side is also remote (outer side 61, 61 '), at a point, or the side of the inlet channel 7, 7'/the outlet channel 8, 8 ', which side is" facing the valve axis or the valve

seat ring center

50, 50' ", intersects the side of the

annular cooling duct

6, 6 ', which side is also facing (inner side 62, 62') at a point.

In the variant shown, the inlet longitudinal centre axis 77, 77 ' extends tangentially to the inner channel wall (inner side surface 62, 62 ') of the

annular cooling channel

6, 6 ' at the valve seat and thus intersects it at a point. The outlet flow channels 8, 8' branch off from the annular cooling channel 6 via the outlet openings 80, wherein the output longitudinal center axis 88 in the exemplary embodiment shown also runs tangentially to the inner channel 62 of the annular cooling channel 6. The shape of the inlet apertures 70,70 'and the outlet apertures 80, 80' is for this purpose substantially elliptical, respectively.

The tangential inflow and outflow allows a circulating flow with little turbulence and good cooling on the circulation paths 90, 90 'while obtaining small pressure losses, thereby maintaining a small short circuit flow on the short circuit paths 91, 91'. This ensures cooling of the short-circuit flow region between the inlet opening 70,70 ' and the outlet opening 80,80 ', but retains sufficient coolant for cooling of the region of the valve seat ring 5 which is subjected to high thermal loads on the circulation path 90, 90 ' between the inlet opening 70,70 ' and the outlet opening 80,80 '.

According to the invention, the discharge ducts 8, 8' can branch off from the annular cooling channel 6 in an angular range between the tangential and the radial direction. Tangential means here that the flow direction in the outlet ducts 8, 8' corresponds to the flow direction in the cooling duct 6, i.e. the angle is equal to 0 °.

Radial here means that the angle between the flow direction in the cooling channel 6 and the flow direction in the outlet channels 8, 8' is 90 °.

By varying the angle between the row flow channels in the region of the outlet openings 80,80 ' and the flow direction in the cooling channel 6, it is possible to adjust the pressure ratio, and in particular also the coolant quantity, between the circulation path 90, 90 ' and the short-circuit path 91,91 ' and to optimize the cooling effect for each application.

In the exemplary embodiment shown, the advantageous cooling effect also occurs in particular as follows: the inlet channels 7, 7' are arranged on the side of the valve seat ring 5 facing the valve bridge 100 between the exhaust valves, or open out on said side. Since a high thermal load occurs in particular in the region of the outlet-side valve bridge 100, the coolant which is fed in again here and has a lower temperature can perform a good function. When the inlet channels 7, 7' extend on the valve bridge 100 side, it is advantageous even in variants with fewer valves.

Fig. 8 shows a view in which the inlet channel 7 'opens into the annular cooling channel 6 and the outlet channel 8' leaves the annular cooling channel again. Here, an angle scale is shown which represents 0 ° at the inlet of the inlet channel 7 'and between 225 ° and 270 ° at the outlet of the outlet channel 8', whereby a circulating flow in the range of 195 ° to 345 ° is obtained. The direction of the row of flow channels 8' is between tangential and radial, i.e. the output angle β is between 0 ° (tangential run) and 90 ° (radial run). The row channels 8 'shown in solid lines have a very gentle course, whereas the row channels 8' shown in dashed lines extend at an angle β close to 90 °. A valve connecting line 200 is shown between the valve seat ring centre points 50 of the

exhaust valve holes

2a, 2 b.

In the embodiment shown for example in fig. 3, the inlet channels 7, 7 'and the outlet channels 8, 8' extend in a common first plane, wherein the first plane is located in the page. This ensures simple machining, for example by rapid positioning of the drill during drilling or by simple insertion of the drill core during casting. In a variant of the invention, the inlet channel 7, 7 'of each valve seat extends in a first plane and the outlet channel 8, 8' extends in a second plane, fig. 4 showing a variant with the outlet channel 8 'illustrated by a broken line, the outlet channel 8' being slightly offset towards the cylinder head sealing plane 110. The first plane then extends perpendicular to the page and coincides with the input longitudinal center axis 77 ', and the second plane also extends perpendicular to the page and coincides with the output longitudinal center axis 88'. Here, the first plane is parallel to the second plane, both parallel to the head seal plane 110 or the valve seat ring plane 500 (see, e.g., fig. 6) defined by the valve seat ring 5 and extending parallel to the head seal plane 110 in the illustrated embodiment. As can be seen, the first and second planes also extend perpendicular to the valve axis 55 in the illustrated embodiment (see fig. 5-7). In another variant, as shown in fig. 7, the first plane extends obliquely with respect to the second plane, this embodiment being visible through the inlet channel 7' shown by a dashed line. The two planes are in turn perpendicular to the page, wherein the first plane coincides with and is represented by the input longitudinal center axis 77 'and the second plane coincides with and is represented by the output longitudinal center axis 88'.

As fig. 1 and 3 show, but in particular fig. 7, the outlet ducts 8, 8' are connected to a cylinder head cooling jacket 120 which is moved downward in the direction of the cylinder head sealing plane 110. The presence of two cylinder head cooling jackets can be, for example, an upper (i.e., remote from the cylinder head sealing plane 110) cylinder head cooling jacket. The region of the outlet channels 8, 8 'which is remote from the valve seat ring 5 is closed off by plugs 130, 130' on the outside of the cylinder head 1 after connection to the cylinder head cooling jacket 120.

Naturally, variants are also possible in which the outlet ducts 8, 8' extend to the outer side of the cylinder head 1 without being connected to the upper cylinder head jacket 120. Valve seat cooling can also be carried out, for example, by means of a separate cooling circuit.

To this end, the invention allows optimal and less turbulent valve seat cooling, which can be simply manufactured and does not require complex machining steps. By means of the angular extent of the circulation paths 90, 90 'and the angular course of the outlet ducts according to the invention, optimum cooling of the valve seats 5, 5' and complete circulation also via the short-circuit path can be achieved.

Claims

1. A cylinder head (1) for an internal combustion engine having at least one cylinder, having at least one valve seat ring (5) for a poppet valve, wherein the valve seat ring (5) is provided with an annular cooling channel (6, 6 '), which annular cooling channel (6, 6') extends at least partially around the valve seat at least between at least one inlet opening (70,70 ') of an inlet channel (7, 7') and at least one outlet opening (80, 80 ') of an outlet channel (8, 8'), wherein the inlet channel (7, 7 ') and the outlet channel (8, 8') are arranged on the same side of the cylinder,

it is characterized in that the utility model is characterized in that,

the inlet channel (7, 7 ') opens into the annular cooling channel (6, 6 ') substantially tangentially via the inlet opening (70,70 '),

an annular flow path (90, 90 '), i.e. a lengthy annular flow region of the annular cooling channel (6, 6') of the valve seat, extends between the inlet opening (70,70 ') and the outlet opening (80, 80') through an angular range of 195 ° to 345 ° from said inlet opening (70,70 '), and the discharge channel (8, 8') branches off from the annular cooling channel (6, 6 ') via the outlet opening (80, 80') in an angular range between tangential and radial;

the annular cooling channel (6, 6 ') extends completely around the valve seat ring (5) and in the flow direction the circulation path (90, 90 ') extends between the inlet opening (70,70 ') and the outlet opening (80, 80 '), while a short-circuited path (91,91 ') extends between the outlet opening (80, 80 ') and the inlet opening (70,70 '), on the one hand a short-circuited flow between the two openings (70,70 ', 80,80 ') occurs in the short-circuited path (91,91 '), and on the other hand a cooling flow around the valve seat along a lengthy path in the circulation path (90, 90 ').

2. The cylinder head (1) as claimed in claim 1, characterized in that the longitudinal centre axis (77, 77 ') of the inlet channel (7, 7') and/or the longitudinal centre axis (88, 88 ') of the outlet channel (8, 8') extends tangentially to the inner channel wall (62, 62 ') of the annular cooling channel (6, 6') of the valve seat.

3. The cylinder head (1) according to claim 1 or 2, characterized in that the inlet channel (7, 7 ') and the outlet channel (8, 8') extend in a common first plane.

4. The cylinder head (1) according to claim 1 or 2, characterized in that the inlet channel (7, 7 ') extends in a first plane and the row of channels (8, 8') extends in a second plane, wherein the first plane is parallel to the second plane.

5. Cylinder head (1) according to claim 4, characterized in that the first plane and/or the second plane are parallel to the valve seat ring plane (500).

6. The cylinder head (1) according to claim 1 or 2, characterized in that at least the row of flow channels (8, 8') is connected to a cylinder head cooling jacket (120).

7. Cylinder head (1) according to claim 1 or 2, characterized in that at least two valve holes (2a, 2b, 3a, 3b) are provided, the inlet channel (7, 7') being arranged on the side of the valve seat facing the valve bridge (100) between the valve holes (2a, 2b, 3a, 3 b).

8. Cylinder head (1) according to claim 1 or 2, characterized in that two exhaust valve openings (2a, 2b) and/or two intake valve openings (3a, 3b) are provided, wherein at least the intake channel (7, 7 ') of the annular cooling channel (6, 6') of the valve seat ring (5) leading to the exhaust valve openings (2a, 2b) is arranged on the side of the valve seat ring (5) facing the exhaust valve bridge.