DE2728903A1 - Piston and cylinder of IC engine - are shaped to produce turbulence and motion away from spark plug - Google Patents

Abstract

A piston (3) reciprocates in a cylinder (1) with a cylinder head (2). The inlet and exhaust valves and a sparking plug are contained in the cylinder head. The top of the piston has an upstanding projection (5) in its centre. The underside of the cylinder has a corresponding recess but the recess is wider than the upstand on the piston. The valves overlap the upstand and the sparking plug is at the side of the recess. As the piston rises the upstand pushes the mixt. out circumferentially into the part of the recess outside the upstand. This produces good mixing and sweeps the burning gases away from the sparking plug. This results in cleaner combustion in a high speed knock free engine.

Description

Process for improving the mixture formation and accelerating the combustion of the mixture Internal combustion engines and internal combustion engine for carrying out the method

The invention relates to a method for improving the mixture formation and accelerating the combustion of the mixture in internal combustion engines with a combustion chamber formed between a cylinder and a piston The invention relates to an internal combustion engine for performing this method.

The aim of the invention is to provide such a method and a:

to train such an internal combustion engine, which is both through '

very low levels of poisonous gases, especially CX , HC and4 * -. _f .;

NOx, with a very low Ver-f «J < H

fuel consumption is to be achieved. In particular, the method and the machine are intended to be used in an Otto engine Find. But it is also intended for diesel engines, i.e. engines for compression ignition.

An effective way to reduce fuel consumption and increase performance is to increase the compression ratio known. A knock-free engine with compression

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from 1:10 to 1:12, it is necessary to move the cylinder charge towards the end of the compression process bring to. There are various suggestions for this.

With the DT-PS 866 272 and the DT-OS 26 35 125 this is Mixture from the squeeze spaces that form between part of the piston and part of the cylinder head into one Firing chamber promoted to the candle.

In DT-OS 15 26 293, the mixture is before the end of the Compaction process rotating promoted past the candle.

In the first two cases, the mixture is conveyed to the candle in a combustion chamber with a candle. This creates a prevents and does not encourage rapid spread of the burning gases, as the flow goes to the candle. In the DT-OS 15 26 293, the mixture is probably conveyed in one direction rotating past the candle; However, it is there is no flow of the mixture in the width to the ends of the combustion chamber.

The object of the invention is therefore to propose a method and an internal combustion engine with which or with which very low levels of poison gas together with a very can achieve low consumption.

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To solve this problem, the method according to the invention is characterized in that the mixture is swirled through towards the end of the compression process and from its ignition point flows away.

Because the mixture is swirled well before and during its combustion and the flow of the mixture before the Top dead center is directed away from the ignition point, in deviation from the previous teaching, can be used in internal combustion engines burn with high compression without knocking. At the same time, these measures accelerate the combustion. With the good turbulence makes it possible to burn lean mixtures of lambda 1.2 to 1.4 properly, which is too much low CO, HC and NOx proportions in the exhaust gas. With the turbulence and the direction of flow away from the ignition point together with the combustion acceleration achieved as a result, it is possible to compress the internal combustion engine highly, which an increase in performance and very low consumption.

It is preferred if the flow of the mixture towards the end of the compression process away from the ignition point in at least runs in two directions. This supports the important basic idea of the invention, according to which the flame front is spread very quickly over the entire volume of the combustion chamber.

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The novel internal combustion engine for performing this method is characterized in that at least one Pinch gap is formed between the piston and the cylinder and that the combustion chamber has a cross section which expands from the area of the ignition location. The pinch gaps or the pinch gaps cause the desired very good swirling of the mixture - or the combustion air in the case of a diesel engine - before and during combustion of the mixture. At the same time, the cross-section of the combustion chamber is widened starting from the area of the ignition location that the area of the highest flow velocity is in the area of the ignition location, with the Direction of flow is directed away from the ignition point.

If the internal combustion engine is designed as a gasoline engine, i.e. with a spark plug reaching into the combustion chamber, the ignition location is the location of the electrodes of this spark plug. When the internal combustion engine is designed as a diesel engine, i. with self-ignition, the area of the mouth of the injection nozzle in the combustion chamber is referred to as the ignition location. At a Such training as a diesel engine, it is preferred if the injector injects the fuel in the direction of the Injection nozzle injects combustion air flowing away.

The combustion chamber can be formed in the cylinder head or in the piston head or in both components. Unless

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the combustion chamber is located in the piston, it is preferred if the lower surface of the cylinder head with valves essentially is flat.

To achieve the desired direction of flow away from It is preferred for the ignition location if an elevation is formed on the upper side of the piston which has a U / and which extends is located close to the ignition point, and which, starting from there, forms an enlarging flow cross-section with the cylinder jand laterally.

This increasing flow cross-section can both be formed in a plane perpendicular to the axis of the piston, u / ie also in a plane in the cylinder axis, and also in both planes, i.e. three-dimensional.

The invention is illustrated below with the aid of exemplary embodiments explained in more detail, from which further important lYl features result. It shows:

Fig. 1 is a section through a first embodiment of the essential components of a novel internal combustion engine along the line C-D of FIG. 2;

Fig. 2 is a section along the line A-B of Fig. 1;

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FIG. 3 shows a section corresponding to FIG. 2 in a different embodiment.

The figures show a cylinder 1 with a cylinder head. In the cylinder, a piston 3 runs in the direction of the arrow 4. On the An elevation 5 is formed on the top of the piston 3. In the cylinder head there is an inlet valve 6, an outlet valve 7 and an opening 8. When the internal combustion engine is designed as a gasoline engine, there is a spark plug in the opening 8 used. When training as a diesel engine, there is an injection nozzle there.

On the lower edge of the cylinder head surfaces 9 and 10 are formed, which form squeeze spaces with the piston 3 towards the end of the compression process. Then on the inside edges These surfaces 9, 10 adjoin surfaces 12, 13 which are inclined with respect to the cylinder axis 11. Arrows 14.15 indicate the direction of flow of the mixture (case of the Otto engine) at the time at the end of the compression process, i.e. when the piston 3 moves upwards Diesel engine, the arrows 14.15 indicate the direction of flow of the diesel oil injected there and the flowing fuel gases.

The mode of operation of the internal combustion engine described so far is as follows:

The fuel-air mixture is fed through the open inlet

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valve 6 sucked into the cylinder head 2. During the compression process, the mixture from the piston to the right and left of the combustion chamber is pressed into the combustion chamber by a squeezing effect below the surfaces 8 and 9 in the upper area of the piston path. In addition, the mixture above the elevation Jt is pressed into the combustion chamber on all sides. This is how a

: is very intense agitation of the mixture, as it is with the

Irri;,> ^: previously known combustion chambers is not the case. U

The elevation \ is designed so that it is close to the Opening B (spark plug) forms a narrow gap 17 in the combustion chamber, which becomes more and more to the right and left expanded (see Fig. 1). This creates a conveyance of the mixture in the direction of the upper part of the piston movement the arrows 14 and 15. The ignition and combustion begins about 20-30 before the top dead center of the piston. So will the mixture ignited by the candle in these directions of the arrows promoted. This means that the burning gas mixture moves away from the candle at high speed in two directions is conveyed into the not yet burning mixture. This shortens the burning time so that it ignites later can be, less pressure takes place against the upward going piston before the top dead center and also at higher compression no knocking combustion can occur. All of this leads to a considerable increase in efficiency the internal combustion engine in dor increase the

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Performance and reduced consumption.

With this good mixing and rapid combustion, perfect operation with mixtures of lambda 1.2 to 1.4 possible, which results in very small amounts of CO, HC and NOx in the exhaust gas.

Thus, the stricter emissions regulations from 1982 onwards without additional expensive measures, such as catalytic converter, afterburner or injection, are very inexpensive and very low Consumption are met.

While Figs. 1 and 2 show an embodiment at which the combustion chamber is located in the cylinder head 2, FIG. 3 shows an embodiment in which the combustion chamber 16 is in the piston.

A good vortex is achieved through the measures described achieved, combined with the fact that the flame front in a very short time with high compression the entire Has reached the volume of the mixture. This results in the task of the invention solved. In the area of arrows 14 and 15, there is little or no turbulence, because otherwise through Frictional losses and detachment the flow velocity would be reduced there, which is not the aim. Rather, the flow is quickly passed on to the

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other parts of the combustion chamber that are further away from the ignition point. The flow to the point of ignition therefore takes place in the period until the piston 3 has reached top dead center. The surfaces that limit the flow path in the area of these arrows 14, 15 are flow guide surfaces,
whose cross-section increases steadily in this direction of the arrow. Through the squishy gaps in the area of the surfaces
9, 10, 12 and 13 a good vortex is achieved. These surfaces also form flow guide surfaces.

Uieil an essential feature of the invention is, contrary to the previous teaching, the mixture towards the end of the compression process from its ignition location (spark plug)
to let it flow away, protection is desired for this measure alone, both for gasoline engines and

with
also diesel engines or internal combustion engines rotary pistons.

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Claims (7)

Claims .1.) Process for improving mixture formation and acceleration the combustion of the mixture in internal combustion engines with one between a cylinder and a Piston designed combustion chamber, characterized in that towards the end of the compression process, the mixture flows away from its ignition point. 2. The method according to claim 1, characterized in that the flow of the mixture towards the end of the compression process away from the ignition point in 809883/0153 -2- Telephone: Lindau (083 82) 6917 Telegraph: Office hours: Bank accounts: 05 4374 by arrangement Bayer. Vereinsbank Lindau (B) No. 120 8578 (BLZ 735 200 74) Hypo-Bank Lindau (B) No. 6670-278 920 (BLZ 735 206 42) Volksbank Lindau (B) No. 51720000 (BLZ 735 90120) Postal checking account: Munich 29525-809 ORIGINAL INSPECTED runs in at least two directions. 3. Internal combustion engine for performing the method according to claim 1 or 2, characterized in that that at least one nip (9,10) is formed between the piston (3) and the cylinder (1) and that the combustion chamber (16) has a cross section which widens from the area of the ignition location (8). 4. Internal combustion engine according to claim 3, characterized in that in their training as Internal combustion engine with compression ignition at the ignition point (8) an injection nozzle is provided, the fuel in the direction the combustion air flowing away from the injector injects. 5. Internal combustion engine according to claim 3 or 4, characterized in that the combustion chamber (16) located in the piston (3) and the lower surface of the cylinder head (2) formed with valves substantially flat is. 6. Internal combustion engine according to claim 3 to 5, characterized characterized in that an elevation (5) is formed on the top of the piston (3), which one Wall that is close to the ignition point (8) and which, starting from there, merges laterally with the cylinder wall 809883/0153 -3- forms an extremely large flow cross-section. 7. Internal combustion engine according to claim 3 to 6, characterized marked that the combustion chamber (16) located in the piston (3). 809883/0153