EP3333398A1 - Cylinder head - Google Patents

Abstract

The invention relates to a cylinder head (1) of a liquid - cooled internal combustion engine, wherein the cylinder head (1) has a cooling chamber arrangement (5) which borders on a fire deck (3) and through an intermediate deck (4) arranged substantially parallel to the fire deck (3) a lower side partial cooling space (5a) and an upper partial cooling space (5b) are subdivided, the upper part cooling space (5b) being arranged on a side of the intermediate deck (4) facing away from the fire deck (3) in the direction of a cylinder axis (2) and the upper part cooling space (5b) (5b) and the lower part of the cooling chamber (5a) via at least one, about the cylinder axis (2) extending overflow opening (6) are flow-connected, which is preferably subsequently arranged on a receiving sleeve (7). Object of the present invention is to provide a cylinder head (1), which has an optimal cooling thermally stressed areas. This object is achieved according to the invention in that the overflow opening (6) has at least one annular segment segment (6a) extending around the cylinder axis (2) and one outgoing bulge section (6b) leading away from the cylinder axis (2) in the radial direction.

Description

The invention relates to a cylinder head of a liquid-cooled internal combustion engine, wherein the cylinder head has a refrigerator space adjacent to a fire deck and is divided by a substantially parallel to the fire deck arranged intermediate deck in a Feuerdeckseitigen lower part of the refrigerator and an upper part of the refrigerator, the upper part of the refrigerator on a in Direction of a cylinder axis facing away from the fire deck side of the intermediate deck is arranged and the upper part of the cooling chamber and the lower part of the cooling space via at least one extending around the cylinder axis overflow are connected, which is preferably arranged on a receiving sleeve. The invention also relates to an internal combustion engine with such a cylinder head.

From the AT 005 939 U1 The applicant is a cylinder head is known in which the coolant flows from the upper part of the cooling chamber via an annular overflow between the intermediate deck and a receiving sleeve for a central component in the lower part of the cooling chamber. From there, the coolant is discharged via overflow into the cooling chamber of the crankcase. Although the valve bridges are flowed through evenly, but without special directivity, which can bring disadvantages in terms of the cooling effect in certain applications. A comparable solution shows the AT 503 182 A2 ,

In the AT 510 857 B1 an inflow channel is provided between an upper and lower partial cooling space, which has a ring-shaped or ring-segment-shaped inlet opening in a central area. This is an adaptation to the local thermal requirements of the subsequent valve bridge passages sought in order to improve the heat dissipation in the area of the exhaust valve seats and the valve bridges.

The known arrangements have the disadvantage that only an insufficient adaptation of the cooling of thermally heavily loaded areas of the cylinder head is possible, which may prove necessary in certain applications. The flow distribution to the various radial cooling channels can only be adjusted via the size of the overflow openings to the cylinder housing. As a result, the radial cooling channels of the inlet side are cooled as well as on the outlet side, but this is disadvantageous in relation to the temperature distribution on the fire deck. The resulting uneven temperature distribution on the fire deck results in material stresses in the cylinder head. At the same time, the cross-sectional area of the overflow openings can only be extended to a limited extent for reasons of strength of the cylinder head, so that there is a lack of coolant or disadvantageous pressure conditions can occur. Furthermore, no targeted flow around the receiving sleeve in the lower part of the cooling chamber is possible through an annular overflow because the cooling water flows in the vertical direction through the overflow on the fire deck and subsequently directly into the radial cooling channels.

The object of the invention is to avoid these disadvantages and to ensure optimum cooling of thermally highly stressed areas of the fire deck and the receiving sleeve.

This object is achieved by a cylinder head mentioned above according to the invention in that the overflow has at least one ring segment segment extending around the cylinder axis ring segment portion and one of them outgoing, pointing away in the radial direction of the cylinder axis bulge portion. In other words, therefore, the overflow opening has a first section which extends in a circle-segment-shaped manner about the cylinder axis and from which a second section proceeds, which is designed as a radial bulge section pointing away in the radial direction from the cylinder axis.

A circular ring segment according to the invention is a circular ring section which extends over an angular range of less than 360 °.

For the purposes of the present disclosure, the cylinder axis is understood to mean a longitudinal center axis of a cylinder which runs essentially normal to a fire deck or a cylinder head density plane.

Due to the limited expansion of the ring segment section and bulge section, the flow velocities in the transition between the partial cooling chambers increase and through this concentrated flow, in particular due to the bulge section, the cooling of thermally highly loaded areas on the fire deck and in the area of valve bridges is increased and thus the temperature is reduced.

In a variant of the invention, the ring segment section extends over a first angle about the cylinder axis, which is between 20 ° and 180 °, preferably between 30 ° and 90 ° and particularly preferably 40 ° to 50 °. The bulge portion extends through a second angle about the cylinder axis, which is between 5 ° and 45 °, preferably between 5 ° and 20 °. Conveniently, the second angle is smaller than the first angle.

It is particularly advantageous if the overflow opening, starting from the receiving sleeve, is arranged to extend in the direction of an outlet channel-preferably between two exhaust valves. As a result, the entire coolant flow in the upper part of the cooling chamber is concentrated on the outlet side and improved cooling of the outlet channel wall and an outlet valve guides is achieved. Furthermore, the flow through the inlet side is slightly reduced due to the concentrated flow through the outlet side. This results in a slight increase in temperature in the intake valve bridge, which causes the temperature level on the entire fire deck is very balanced and thus the material stresses can be drastically reduced.

A particularly focused flow with favorable cooling effect can be achieved if the width of the ring segment section running in the radial direction is smaller than the width of the bulge section extending in the circumferential direction. In other words, the width of the ring segment portion is defined as its extent in the radial direction while the width of the bulge portion is defined as an extent in the circumferential direction about the cylinder axis.

The ring segment section has a greater extent in the circumferential direction around the cylinder axis (hereinafter referred to as the length of the ring segment section) than in the radial direction (extension in the radial direction hereinafter referred to as the width of the ring segment section). In contrast, the bulge portion in the radial direction has a greater extent (hereinafter referred to as the length of the bulge portion) than in the circumferential direction around the cylinder axis (this extent in the circumferential direction is hereinafter referred to as the width of the bulge portion). An arrangement favorable for the flow conditions results when the overflow opening extends in the circumferential direction about the cylinder axis substantially between two connecting lines extending from the cylinder axis to one valve axis of two different valves, preferably between connecting lines from the cylinder axis to the exhaust valve axes of the two exhaust valves. In a variant of the invention, the bulge section extends along a valve symmetry plane extending between two valve axes, preferably the valve axes of the outlet valves, normal to the fire deck. Advantageously, the extension of the bulge section ends in the radial direction in front of a connection plane between the two valve axes. As a result, a favorable balance between the cooling effect and the strength of the cylinder head is achieved.

It is advantageous for the bulge section to extend in a direction away from the cylinder axis via a radial cooling channel extending through an outlet valve bridge. As a result, the region of the exhaust valve bridge subjected to high thermal stress can be cooled particularly effectively.

For good cooling, it is also advantageous if the overflow is fluidly connected via a arranged in the lower part of the cooling chamber around the receiving sleeve distribution ring with radially away from the distribution ring cooling channels in the lower part of the cooling chamber. As a result, the receiving sleeve in the lower part of the cooling chamber can be flowed around.

The object of the invention is also achieved by an initially mentioned internal combustion engine with a cylinder head according to one of the variants described above.

Fig. 1

eine schematische Darstellung eines erfindungsgemäßen Zylinderkopfs in einem Schnitt gemäß der Linie I-I in Fig. 2;

Fig. 2

den Zylinderkopf aus Fig. 1 in einem Schnitt im Bereich eines oberen Teilkühlraumes gemäß der Linie II-II in Fig. 1; und

Fig. 3

den Zylinderkopf aus Fig. 1 in einem Schnitt im Bereich eines unteren Teilkühlraumes gemäß der Linie III-III in Fig. 1.

The invention will be explained in more detail below with reference to a non-limiting embodiment, which is illustrated in the figures. Show:

Fig. 1

a schematic representation of a cylinder head according to the invention in a section along the line II in Fig. 2 ;

Fig. 2

the cylinder head off Fig. 1 in a section in the region of an upper part of the cooling chamber according to the line II-II in Fig. 1 ; and

Fig. 3

the cylinder head off Fig. 1 in a section in the region of a lower part of the cooling chamber according to the line III-III in Fig. 1 ,

Fig. 1 shows in a section of an internal combustion engine 100, a liquid-cooled cylinder head 1 with at least one cylinder, not shown, which is arranged along a cylinder axis 2. The cylinder head 1 has a fire deck 3 in the direction of a combustion chamber of the cylinder. An intermediate deck 4 divides a cooling space arrangement 5 into a lower partial cooling space 5a near the fire deck 3 and an upper partial cooling space 5b adjoining in the direction of the cylinder axis 2.

The intermediate deck 4 has at least one overflow opening 6 per cylinder for the flow connection between the upper part cooling space 5b and the lower part cooling space 5a, which is formed between the intermediate deck 4 and a receiving sleeve 7. The receiving sleeve 7 serves for example for receiving a fuel injection device or a spark plug and is arranged substantially concentric with the cylinder axis 2. According to Fig. 2 closes the overflow opening 6, starting from the cylinder axis 2 in the radial direction of the receiving sleeve 7 and according to the invention has an at least partially around the cylinder axis 2 and the receiving sleeve 7 extending annular segment portion 6a with an additional extending in the radial direction bulge portion 6b. In the embodiment as top-down cooling, ie when the coolant flows from the upper 5b into the lower part cooling space 5a, Thus, a favorable distribution of the coolant and cooling, in particular of the areas subjected to high thermal stress, can be achieved.

The annular segment portion 6a has the shape of a circular ring segment and extends in the circumferential direction over a first angle α about the cylinder axis 2 and the receiving sleeve 7. The first angle α is between 20 ° and 180 °, wherein in the illustrated embodiment, an angle of about 65 ° is realized. The substantially radially extending bulge portion 6b extends in the circumferential direction over a second angle β, which is between 5 ° and 45 °, wherein about 16 ° are implemented in the illustrated embodiment.

The second angle β is preferably small compared to the first angle α. Thus, the coolant can be directed specifically to the areas of the valve axes, which are particularly highly loaded thermally high outlet side.

In addition to the aforementioned angular ranges in the circumferential direction about the cylinder axis 2, the extensions in the radial direction, starting from the cylinder axis 2, also have to be taken into account. The annular segment section 6a has a greater extension in the circumferential direction than in the radial direction. The extent in the radial direction is the width of the ring segment portion 6a. The bulge portion 6b can be designed differently depending on the embodiment variant: The width of the bulge portion 6b, ie its extent in the circumferential direction about the cylinder axis 2, can either be smaller, equal or greater than the extent of the bulge portion 6b in the radial direction (starting from the cylinder axis 2). In the illustrated embodiment according to Fig. 2 and Fig. 3 the width of the bulge portion 6b is substantially equal to the length, that is to the extent in the radial direction. A favorable coolant distribution when flowing through the overflow opening 6 can be achieved if, as implemented in the illustrated embodiment, the radial width of the annular segment section 6a is smaller than the width of the bulge section 6b extending in the circumferential direction about the cylinder axis 2.

In order to achieve the best possible balance between the pressure loss when flowing through the overflow opening 6 and the cooling effect in the region of the thermally highly stressed areas such as receiving sleeve 7 and valve bridges, the dimensioning of the overflow 6 is selected as follows: The overflow 6, in particular the ring segment section 6a is between two arranged from the cylinder axis 2 to a respective valve axis 8a, 8b of two different valves connecting lines A. Basically, these may be the exhaust valve axes 8a and the intake valve axles 8b or also each a connection line A to an exhaust valve axis 8a and an intake valve axis 8b extend in the illustrated embodiment according to Fig. 2 but the connecting lines A between the cylinder axis 2 and the Auslassventilachsen 8 a are arranged. This is advantageous because the highest thermal loads occur during operation on the outlet side. The connecting line A connects as a respective valve axis 8a, 8b with the cylinder axis 2. At the same time extending the bulge portion 6b along a between two valve axes 8a, 8b - in the illustrated embodiment between the Auslassventilachsen 8a - normal to the fire deck 3 extending valve symmetry plane Z. The valve symmetry plane Z In the radial direction, the extension of the overflow opening 6, in particular of the bulge section 6b, ends in front of a connecting line between the two valve axes 8a assigned to the valve symmetry plane Z. , 8b - in the illustrated embodiment, these are the exhaust valve axes 8a.

The figures show with reference to arrows P, the flow of a coolant in a cylinder head according to the invention 1. According to the arrows P in Fig. 1 the coolant passes from a pressure source, not shown, for example, a coolant pump, through a coolant inlet into the upper part of the cooling chamber 5b, flows through the overflow 6 in the vertical direction in the lower part of the cooling chamber 5a, wherein it impinges directly on the fire deck 3 and this cools.

As in Fig. 3 is shown, the coolant divides in the lower part of the cooling chamber 5a via a distribution ring 10 on, for example, four radial cooling channels 9a, 9b, 9c, 9d and flows through openings 11a, 11b, 11c, 11d further into a crankcase. Of course, fewer radial cooling channels and fewer openings may be provided.

About the distribution ring 10 a targeted flow around and thus cooling of the receiving sleeve 7 allows. The radial cooling channels 9a, 9b, 9c, 9d are arranged in particular in the region of valve bridges - due to the design of the overflow opening 6 with ring segment section 6a and bulge section 6b, a steering of the coolant flow is achieved and in particular the outlet valve bridge 90, ie the first radial cooling channel 9a between the outlet channels 8, efficiently cooled. How out Fig. 2 in synopsis with Fig. 3 can be seen, the bulge portion 6b extends in a radially away from the cylinder axis 2 direction over the extending through an outlet valve bridge 90 first radial cooling channel 9a. The positioning "over" is here to be understood in a direction away from the fire deck 3 along the cylinder axis 2 direction. The first radial cooling channel 9 a is part of the lower part of the cooling chamber 5 a and the bulge portion 6 b is performed in the region of the intermediate deck 4. On the one hand, a larger amount of water is supplied to this first cooling channel 9a, on the other hand, the outlet valve bridge 90 is additionally cooled in the region of the intermediate deck 4.

This steering effect is enhanced by the positioning of the openings 11a, 11b, 11c, 11d, through which the coolant from the cylinder head 1 runs into the crankcase.

The geometry shown in the exemplary embodiment in the figures and the outlet-side positioning of the overflow opening 6 result in concentrated cooling of the outlet side both in the upper part cooling space 5b and in the lower part cooling space 5a. As a result, an optimal cooling of the outlet channel 8 and the outlet channels, of exhaust valve guides 7a, 7b (see Fig. 2 ) and subsequently the fire deck 3 in the highly thermally stressed area of an outlet valve bridge 90. This results in a homogeneous temperature level on the entire fire deck 3 and thus there are lower material stresses in the cylinder head 1. Under valve bridge, or exhaust valve bridge 90, the material accumulation between the gas exchange valves, not shown, and the exhaust valves understood. The exhaust valve bridge 90 is subjected to high thermal loads.

In addition to the variant shown in the embodiment in the figures, other variants are possible where, for example, the bulge portion 6b is disposed in the region of the intake valve bridge or the inlet-Auslaßventilbrücke or that further ring segment sections are provided, which are each or partially connected with bulge portions.

The invention thus allows an increase in the flow velocities in the transition between the partial cooling chambers 5a, 5b and through this concentrated flow, in particular due to the Ausbuchtungsabschnitts 6b, the cooling of thermally highly loaded areas on the fire deck 3 and in the range of valve bridges - especially the exhaust valve bridge 90. increases and thus reduces the temperature. As a result, thermal stresses and consequent damage to cylinder heads are prevented.

Claims (10)

Cylinder head (1) of a liquid-cooled internal combustion engine, wherein the cylinder head (1) has a cooling chamber arrangement (5), which borders on a fire deck (3) and through an intermediate deck (4) arranged substantially parallel to the fire deck (3) into a fire compartment side lower partial cooling space (5a) and an upper part of the cooling chamber (5b) is divided, wherein the upper part of the cooling chamber (5b) on a in the direction of a cylinder axis (2) from the fire deck (3) facing away from the intermediate deck (4) and the upper part of the cooling chamber (5b) and the lower part of the cooling chamber (5a) via at least one, about the cylinder axis (2) extending overflow opening (6) are connected, which is preferably then arranged on a receiving sleeve (7), characterized in that the overflow (6) at least one Ring segment segment around the cylinder axis (2) extending ring segment portion (6a) and one of them outgoing, in the radial direction of the cylinder Has axis (2) pioneering bulge portion (6b). Cylinder head (1) according to claim 1, characterized in that the ring segment portion (6a) extends over a first angle (a) about the cylinder axis (2), which is between 20 ° and 180 °, preferably between 30 ° and 90 ° and particularly preferably 40 ° to 50 °. Cylinder head (1) according to claim 1 or 2, characterized in that the bulge portion (6b) extends over a second angle (β) about the cylinder axis (2) which is between 5 ° and 45 °, preferably between 5 ° and 20 ° °. Cylinder head (1) according to one of claims 1 to 3, characterized in that the bulge portion (6b) extends over a second angle (β) about the cylinder axis (2), which is smaller than the first angle (α). Cylinder head (1) according to one of claims 1 to 4, characterized in that in [out of the cylinder axis (2) outgoing] radial direction extending width of the ring segment portion (6a) is smaller than the width extending in the circumferential direction of the Ausbuchtungsabschnitts (6b ). Cylinder head (1) according to one of claims 1 to 5, characterized in that the overflow opening (6) in the circumferential direction about the cylinder axis (2) substantially between two of the cylinder axis (2) extending to each valve axis (8a, 8b) of two different valves connecting lines (A), preferably between the connecting lines (A) of the cylinder axis (2) to the Auslassventilachsen (8a) of the two exhaust valves. Cylinder head (1) according to one of claims 1 to 6, characterized in that the bulge portion (6b) extends along a valve symmetry plane extending between two valve axes (8a, 8b), preferably the exhaust valve axes (8a) of the exhaust valves, normal to the fire deck (3) (Z) extends. Cylinder head (1) according to one of claims 1 to 7, characterized in that the bulge portion (6b) in the direction away from the cylinder axis (2) via a through a valve bridge, in particular an outlet valve (90) extending radial cooling channel (9a, 9b; 9c, 9d). Cylinder head (1) according to one of claims 1 to 8, characterized in that the overflow opening (6) via a in the lower part of the cooling chamber (5a) around the receiving sleeve (7) arranged distribution ring (10) from the distribution ring (10) radially leading away cooling channels ( 9a, 9b, 9c, 9d) in the lower part of the cooling chamber (5a) is fluidly connected. Internal combustion engine (100) with a cylinder head (1) according to one of claims 1 to 9.

Images