DE102009020121A1 - Device for dissipating heat of exhaust manifold of internal-combustion engine, is designed such that unit is formed by surface elements that are arranged such that radiation from one of elements overlaps with radiation of other elements - Google Patents

Abstract

The device is designed such that a unit for increasing emission of thermal radiation (20) is provided at an exterior surface of an exhaust gas conducting component i.e. exhaust manifold (10). The unit is formed by radiation surface elements (18) with radiation surfaces (18a-18c). The radiation surface elements are arranged such that the thermal radiation from one of the radiation surface elements with respect to a main radiation direction overlaps with the thermal radiation of other radiation surface elements in a defined distance from the component and/or radiation surface elements. The radiating surface elements are formed as pyramid-like projections.

Description

The The invention relates to a device for dissipating heat in particular exhaust-carrying components of an internal combustion engine, in particular an exhaust manifold, according to Preamble of claim 1.

A device of the generic type shows, for example, the US 6,990,806 B1 in which cooling fins are provided on an exhaust manifold for internal combustion engines along the pipe guides, which increase the emission surface of the exhaust manifold and thus can cause a decrease in temperature of the flowing in the exhaust manifold, hot exhaust gases. Such a temperature reduction is desirable in particular at full load operation of the internal combustion engine to z. B. to maintain the temperature level of a downstream catalyst of an exhaust gas purification device in a non-harmful area. The cooling fins are arranged so that the radiating surfaces of each adjacent cooling fins are opposite and thus heat is radiated to the respective opposite fin. As a result, "foci" (cut surfaces) are formed, which reduce the emission of the exhaust manifold.

task The invention is an apparatus for discharging Heat exhaust gas components, in particular a To propose internal combustion engine, which in a manufacturing technology simple design improved, targeted heat dissipation ensures an exhaust gas leading component.

These The problem is solved with the features of claim 1. Advantageous developments of the invention are the subject of Dependent claims.

To Claim 1 has a device for removing heat exhaust-carrying components on the component outside surface increasing the emission of heat radiation Means up. According to the invention, these agents by locally distributed and at least one emitting surface formed emitting surface elements, which are so to each other are aligned, that of the at least one emitting surface outgoing heat radiation at least in terms of their Main emission direction not on, at a defined distance arranged, preferably adjacent, radiating surface element is directed and / or that of at least one radiating surface element outgoing heat radiation at least with respect the main direction of radiation not or only in a defined Distance from the component or at least one radiating surface element with the heat radiation of at least one further radiating surface element overlaps.

Thereby may advantageously be known from the prior art, and adverse interactions of adjacent radiating surfaces be avoided, which significantly increases the emission of the components.

Prefers be the radiating elements by locally formed distributed projections whose radiating surfaces essentially no "foci" to each other form. Such projections are in particular in a casting Training of the component easy to produce and local freely distributable, whereby it is avoided that the radiating surfaces illuminate each other or impair their cooling effect.

Especially Preferably, the radiating surface elements or Projections pyramidal with several, essentially plan to be formed radiating surfaces. this makes possible an uncomplicated alignment of the radiating surfaces in a kind of all-round distribution, whereby also areas considered can be less irradiated or temperature should be.

Especially the radiating surface elements each one triangular base with three radiating surfaces show what is taking into account the manufacturing costs has proved to be particularly useful.

In Advantageous development of the invention, the radiating elements be distributed on the component such that their radiation is not directly on adjacent, heat-sensitive components is directed. This succeeds in particular next to inevitable Insulating the temperature load of adjacent components to lower.

After all For example, the component may be an exhaust manifold made of cast iron be on which the Abstrahflächenelemente casting are formed. In particular, cast iron already points next to his high temperature resistance a favorable emissivity of about 0.9 and allows in conjunction with the Example projections as radiating surface elements an effective lowering of the component temperatures.

A Embodiment of the invention is hereinafter with further Details explained by way of example only.

The schematic drawing shows in:

1 a top view of an exhaust manifold for an internal combustion engine with pyramidenarti gene projections as means for lowering the temperature, and

2 a cross section according to line II-II of 1 through the exhaust manifold.

The 1 shows an exhaust manifold 10 for an internal combustion engine with several cylinders. The exhaust manifold 10 has three mounting flanges 12 for connection to the exhaust ducts of a cylinder head, a downstream, with exhaust gas-carrying components such as an exhaust front pipe, a catalyst, etc. connectable outflow flange 14 and the flanges 12 . 14 connecting, cast-together exhaust pipes 16 on.

The exhaust manifold 10 is made of a cast iron by casting and has an emissivity of, for example, about 0.9.

On the outer surface of the exhaust pipes 16 are pyramidal protrusions 18 (see also 2 ) formed as Abstrahlflächenelemente, the spatially distributed in each case three substantially planar, symmetrically distributed radiating surfaces 18a . 18b . 18c exhibit.

Each approximately triangular radiating surfaces 18a . 18b . 18c are aligned so that their heat radiation with adjacent protrusions 18 or whose radiating surfaces do not form foci or cut surfaces which in the 1 and 2 schematically by the main radiation direction characterizing radiation arrows 20 is shown.

Next are the radiating surfaces 18a . 18b . 18c here aligned with each other (see in particular 1 ) that the radiation 20 at least not on the immediately adjacent projections 18 meets. Where in the 1 If necessary, overlaps can either result so far from the exhaust manifold 10 it should be spaced apart that this does not adversely affect the emission or be due to the two-dimensional representation that does not take into account curvatures, that is, the radiations intersect at different elevation levels spaced apart from each other, and do not affect each other or appreciably ,

In particular, the individual projections need 18 or in a general way the individual radiating surface elements are not formed as identical parts, but they can also be designed differently, for example with regard to the inclination of the radiating surfaces against the component surface and / or the basic shape of the individual radiating surface elements.

Of Furthermore, it should be explicitly stated at this stela that the radiating surface elements here only by way of example and preferred are formed as raised projections. in principle but could also be provided the respective circumstances require or permit, optionally recessed radiating surface elements be provided.

The projections 18 (The number varies depending on pipe length, pipe diameter, etc.) are also arranged so that immediately adjacent components 22 2 ) of the internal combustion engine or in the engine compartment of a motor vehicle from the projections are not directly illuminated or heat-stressed. This means that z. B. as in 2 represented, in this area no or only in other directions radiating protrusions 18 are arranged.

The the outer surface of the exhaust manifold 10 enlarging projections 18 affect a desired, rapid heating of the exhaust manifold 10 or the downstream components (in particular for quickly reaching the light-off temperature of a catalyst), since the heat flow in a known manner depends on the fourth power of the surface temperature and therefore its heat radiation at lower temperatures is negligible.

It but it is understood that at full load operation of the internal combustion engine With exhaust gas temperatures up to almost 1000 degrees C corresponding insulation measures and / or ventilation of the engine compartment and / or adjacent Components may additionally be required.

Instead of or in addition to the exhaust manifold 10 can also other, exhaust-gas-carrying components such as Abgasvorrohre and / or catalysts on the outer jacket with corresponding projections 18 be executed.

The projections 18 Instead of being pyramid-shaped, they can also be embodied by other raised geometrical shapes with correspondingly directed emitting surfaces.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - US 6990806 B1 [0002]

Claims (6)

Device for removing heat from, in particular, exhaust gas-carrying components of an internal combustion engine, in particular an exhaust manifold, the component being provided on its outer surface with the means for increasing the emission of heat radiation, characterized in that the means are provided by spatially distributed and at least one radiating surface ( 18a . 18b . 18c ) having radiating surface elements ( 18 ) are arranged, which are arranged and aligned so that the of the at least one emitting surface ( 18a . 18b . 18c ) outgoing heat radiation ( 20 ) at least with respect to their main emission direction not on a preferably arranged in a defined distance, preferably adjacent, radiating surface element ( 18 ) and / or that of at least one radiating surface element ( 18 ) outgoing heat radiation ( 20 ) at least with respect to their main emission direction not or only at a defined distance from the component and / or at least one Abstrahlflächenelement ( 18 ) with the heat radiation ( 20 ) at least one further radiating surface element ( 18 ) overlaps. Apparatus according to claim 1, characterized in that the radiating surface elements ( 18 ) are formed by locally distributed projections. Apparatus according to claim 2, characterized in that at least a part of the radiating surface elements ( 18 ) pyramid-shaped with a plurality of substantially planar radiating surfaces ( 18a . 18b . 18c ) is trained. Apparatus according to claim 3, characterized in that at least a part of the radiating surface elements ( 18 ) a triangular base surface and thus three radiating surfaces ( 18a . 18b . 18c ) having. Device according to one of the preceding claims, characterized in that the radiating surface elements ( 18 ) on the component ( 10 ) are arranged, that of the respective radiating surfaces ( 18a . 18b . 18c ) radiated heat radiation ( 20 ) at least with respect to their main emission direction not on adjacent, in particular heat-sensitive components ( 22 ). Device according to one of the preceding claims, characterized in that the component ( 10 ) is a cast-iron exhaust manifold on which the projections ( 18 ) are formed by casting.