DE2545589A1 - PISTONS FOR COMBUSTION ENGINE, IN PARTICULAR DIESEL ENGINES - Google Patents

Description

Applicant: Mr. Ludwig Eisbett, Ing-grad,

Günter ice bed

85 ^ 3 Hilpoltstein

Representative and Fritz M erte η Authorized delivery officer, patent and civil engineer: 85OI Schwarzenbruck

Brückkanalstr. 25th

Schwarzenbruck, July 9, 1975

Pistons for internal combustion engines, in particular diesel engines

The invention relates to a piston for internal combustion engines, in particular diesel engines, with a combustion chamber arranged in the head of the piston, which at least in the area of the combustion chamber opening a thermally insulating one lying between itself and a sealing jacket of the piston Has use.

When building more modern internal combustion engines, such as diesel engines and others, it has been shown that for optimization the combustion process, it is necessary to pay special attention to the combustion process, In internal combustion engines with combustion chambers that are provided in the piston head and are preferably of spherical design

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it has been shown that it is useful to divide the combustion chamber into two different temperature zones, the zone adjacent to the combustion chamber opening being very hot and the zone adjacent to the combustion chamber floor less hot, i.e. cold, are to be trained. Around these zones the correspondingly different temperature controls to give, inserts are provided in the area of the combustion chamber opening in pistons of this type, which provide thermal insulation are designed and which are arranged in the combustion chambers so that they hardly the temperature from the combustion process between fuel and air components forward to the piston skirt.

A known piston of this type is essentially one of the sealing of the piston against a cylinder wall serving piston head and a piston serving, underlying guide means in the form of a sliding shoe formed, with a preferably rotationally symmetrical and largely spherical shape in the piston head Combustion chamber is provided. The combustion chamber is provided within a jacket, which on his one end carries the piston head with the sealing rings sitting on it and which jacket with its other end is articulated to a pin bearing of a connecting rod. This is also the den on this pin bearing Piston leading means, namely the sliding shoe articulated, and this sliding shoe can be used as a Ring body or as an arm star with on its the cylinder wall facing sides provided jaws be executed. In order for this piston to have different To provide temperature control of the combustion chamber, the combustion chamber has a side facing the combustion chamber opening Use on, which is designed to be heat-insulating and which heat-insulating the combustion chamber against the jacket of the same shields.

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The insert, which in this known embodiment has a ring width in the order of magnitude of the depth of the May have fuel jet at idle, can be designed, for example, as a glow part, which with its ends facing the jacket is attached to this. The glow part is arranged in the combustion chamber in such a way that that it does not prevent the air to be burned from rotating around the axis of the combustion chamber, so that the fuel to be burned can be promoted to the middle of the combustion chamber, where it is there with the existing combustion air burns. In this embodiment, however, it is ignored that for the Combustion would be useful if the injected fuel did not enter the so-called cold part of the combustion chamber achieved, (see DT-PS 1 576 OI5)

This is where the invention comes in, which is based on the object of having different heat zones Further develop the combustion chamber in such a way that the fuel injected into the combustion chamber is in the region of the hot Zone probably reaches the walls of the combustion chamber, but these walls in the area of the less hot or cold zone avoids.

According to the invention, this object is achieved in a piston of the type mentioned in that the insert only with its end facing away from the combustion chamber opening at one the combustion chamber into a hot part adjacent to the combustion chamber opening and a less hot part, the part adjacent to the bottom of the combustion chamber, separating annular zone is attached, and that a the injected fuel from the wall of the combustion chamber and / or a tear-off edge that repels the insert is provided. Through these measures it is achieved that the fuel injected into the combustion chamber, if necessary along

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the wall of the hot ring zone is guided and this fuel only from the point of attachment of the insert from the tear-off edge located at this point is deflected inwards to the middle of the combustion chamber, where it finds warm, rotating combustion air with which this fuel can mix and burn. Another advantage of the invention is seen in the fact that the possibility of different temperature control of the combustion chamber is very hot and less hot Ring zone, the fuel in the hot ring zone heats up very quickly and evaporates, on the other hand, the fuel in the cold ring zone still has enough time to evaporate mix and get to combustion. Depending on the design of this tear-off edge, this can be the one passing by it Direct fuel either abruptly or gradually into the center of the combustion chamber, so that accordingly the size of the piston, the load on the internal combustion engine and the desired temperature profile in the combustion chamber this tear-off edge can be designed.

An advantageous further development of the invention is further characterized in that the annular zone has an opening towards the combustion chamber having an open, annular channel with a shield directed towards the axis of the combustion chamber, and that the edge of the insert can be fixed in this groove by means of the shield.

Such a design, in particular the fastening point for use, has the advantage that it is the changing Temperature loads during the combustion phase of the fuel with the combustion air can follow that means that the insert has the option, due to its one-sided attachment to its so-called cold part,

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namely at the equator of the combustion chamber between hotter and cold ring zone, according to its temperature control, this in the direction of the combustion chamber opening can grow. This also ensures that within this rolled or fixed insert in the No stresses can occur in the combustion chamber which would lead to cracks or fractures of the same.

In cases where the use itself is not yet the required Thermal insulation guaranteed due to its material constellation, it is within the scope of the invention possible that the insert is attached to the ring zone and discharged from the ring zone to the level of the Combustion chamber opening between itself and the sealing jacket has a known air gap as thermal insulation.

According to a further feature of the invention, this air gap can have a depth which is greater than the radial one Expansion travel of the insert at full load of the internal combustion engine.

By this fastening of the insert on the one hand and the provision of such an air gap on the other hand, it is possible, with simple means, to insulate the insert according to the heat, so that the from the combustion of the Fuel with the air resulting temperature largely "remains in the combustion chamber and not to the anyway endangered sealing rings on the head of the piston is released.

A preferred embodiment of the insert has shown that it is particularly favorable if it is characterized by that the immersion depth of the insert and thus also the depth of the annular zone in the combustion chamber is reversed

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proportional to the compression ratio of the internal combustion engine are.

This knowledge applies to combustion chambers of this type, which are largely of any shape, so that from this function, the respectively favorable width of such an insert and its immersion depth in the combustion chamber derived can be.

In order to simplify the production process of a combustion chamber provided with such an insert, a Another feature of the invention is that the attachment of the insert to the ring zone as a rolling point is executed. Another feature can also be characterized in that the rolling point and thus also the Tear-off edge are ring-shaped.

An exemplary embodiment of the invention is shown schematically in the drawing. It shows:

FIG. 1 shows a longitudinal center section through a piston with an insert inserted into it in a cantilever manner and

FIG. 2 is a plan view of the piston in FIG. 1.

On a piston 1, which is essentially composed of a piston head 2, a piston base 5 and a piston head with the foot connecting jacket 4 is formed a combustion chamber 5 is provided within the jacket, which for Has a heat insulating means 6 between itself and the piston head for the purpose of thermal insulation. The combustion chamber 5 * for the purpose of optimizing the Combustion sequence in a so-called hot combustion chamber part a and a so-called cold part or less

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hot part b, has in the area of the parting plane of these parts or in the area of an annular zone 6 a shield 7 which is designed as a so-called tear-off edge for a fuel jet 8 to be injected into the combustion chamber 5. The fuel jet 8, which is injected into the combustion chamber from a nozzle 9, can run along the shell side of the insert facing the center of the combustion chamber or the axis X of the combustion chamber, so that it only starts from the shield 7 or the tear-off edge is directed into the middle of the combustion chamber around the axis X of the combustion chamber. This deflection of the fuel 8 at the tear-off edge or on the shield 7 prevents fuel constituents from reaching the viand 10 of the part of the combustion chamber forming the cold annular zone b. The deflection of the fuel jet 8 can be done in such a way that the fuel constituents are directed into the area of the combustion chamber axis, where they are captured by an air flow rotating around the combustion chamber axis X, made to evaporate and, after mixing with the air constituents, can be burned. The shield 7 provided in the area of the ring zone 6 can, in addition to the intended puncture of the tear-off of the fuel jet 8, also take over the fastening of the insert, for which purpose a channel on the jacket 4 of the piston 1 can preferably be provided behind the shield, into which a Insert the ring flange 12 located on the insert and have it fastened there. For the sake of simplicity, the attachment of the insert 6 via its annular flange 12 can take place in that the shield 7 is designed as a rolling point, so that when the shield is rolled in radially against the jacket k of the piston 1, the latter takes on the task of attaching the insert 6. In cases where the insert 6 due to its material constellation

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The required thermal insulation alone can also be used between this insert and the jacket 4 of the piston 1 a further thermal insulation can be provided, which in the subject of this embodiment in Form of an air gap 15 is executed. The air gap 15 can extend from the attachment point of the insert 6 to the Y plane of the piston head and it can have a gap width necessary for the required thermal insulation. What the breadth of stakes 6 from the combustion chamber opening 14 to the ring zone 6, it has been found that this is particularly it is advantageous if it is inversely proportional to the compression ratio of the internal combustion engine. Analogous to this width of the insert 6, the position of the ring zone 6 results more or less deep in the combustion chamber, whereby the proportions of the hot and so-called cold combustion chamber surfaces also change accordingly, as it does e.g. for the different compression ratios chosen is necessary. For example, if the corapression ratio is high, e.g. 1:24, the ring zone and thus also the rolling point or the tear-off edge will be higher than at a compression ratio of 1: 17 * because at a high compression temperature there is not so much hotter Combustion chamber wall, but more colder combustion chamber walls are required for optimal mixture formation.

In this configuration of the rolling point and thus the shield 7, it is possible that the insert 6 during the Rolling-in process is not stretched, so that very brittle materials such as cast metal, sintered metals, Ceramic and similar, heat-resistant materials can be used as inserts. This is achieved A measure of attachment also in that an external pressure in the direction of arrow P on the jacket 4 of the piston

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is chosen so that the insert 6 and thus also its ^ ing flange 12 when pressed into the channel 11 is just like that a lot of compressive stress receives as the piston skirt is stretched by the actual rolling. Through this training of the insert 6 is achieved that in addition to the different temperature control of the combustion chamber 5, the heat of combustion hardly passed over the jacket 4 to the piston head 2 and hardly passed over this to the sealing rings 15 is, so that these sealing rings do their actual sealing task of the without any particular thermal load Piston head against a cylinder jacket 16 can perceive.

The heat generated when the fuel is burned with the Air constituents can occur in this * version of the combustion chamber mainly via the piston foot J to the Bolt bearing and from here via a Pührungskörper not shown in the drawing to the wall 17 of the Cylinder 16 are delivered. The combustion of the fuel-air components can mainly in the area around the Brennraumaehse X take place, so that this combustion largely without the known pollutant emissions as well Blue smoke, soot and others can occur.

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Claims (1)

Applicant: Mr. Ludwig Eisbett, Ing-grad. Günter ice bed Hilpoltstein Representative and Fritz M e r t e η Authorized Service, Patent and Civil Engineer more powerful: 85OI Schwarzenbruck Brüokkanalstr. 25th Schwarzenbruck, July 9, 1975 Claims (1.! Pistons for internal combustion engines, especially diesel engines, with a combustion chamber arranged in the head of the piston, which at least in the area of the combustion chamber opening has a heat-insulating insert located between itself and a sealing jacket of the piston, characterized in that the Insert (6) only with its end (12) facing away from the combustion chamber opening (] Λ) on one of the combustion chamber (5) into a hot part (a) adjacent to the combustion chamber opening and a less hot part (b) adjacent to the bottom of the combustion chamber , separating annular zone (6) is attached, and that a tear-off edge (7) which repels the injected fuel (8) from the wall (10) of the combustion chamber and / or the insert is provided on this annular zone. E 39
me / sw 709815/0634 2. Piston according to claim 1, characterized in that the ^{annular zone (6 ') has an annular groove (11) open towards the combustion chamber opening (I 1} I-) with a shield (7) directed towards the axis (X) of the combustion chamber (5) ), and that the end (12) of the insert (6) facing away from the combustion chamber opening can be fixed in this channel by means of the shield (7). 3. Piston according to claim 1, characterized in that the insert (6) attached to the ring zone (6 ¹ ) cantilevered and from the ring zone to the plane (Y) of the combustion chamber opening (14) between itself and the sealing jacket (2) has a known air gap (13) as thermal insulation. ^. Piston according to Claim 3 *, characterized in that the depth of the air gap (13) is greater than the radial expansion path of the insert (6) when the internal combustion engine is at full load is. 5. Piston according to claims 1 to 4, characterized in that the immersion depth of the insert (6) and thus also the depth of the annular zone (6 ¹ ) in the combustion chamber (5) are inversely proportional to the compression ratio of the internal combustion engine. 6. Piston according to claims 1 to 3 * characterized in that the attachment of the insert (6) to the Ring zone (6 ') is designed as a rolling point. 7. Piston according to claim 1, characterized in that the rolling point (7) designed as an annular tear-off edge is. . 709815/0634