DE1112670B - Air-compressing, self-igniting injection internal combustion engine with a combustion chamber arranged in the piston - Google Patents

Description

Air-compressing, self-igniting internal combustion engine with a Combustion chamber arranged in the piston The invention relates to an air-compressing, Self-igniting injection internal combustion engine with a rotational body-shaped one arranged in the piston and the combustion chamber constricted at its opening, the one in the area of its opening Has pocket-like bulge, and with an injection nozzle, which the fuel either through the constricted opening of the combustion chamber or through the pocket-like one Bulge through against the combustion chamber wall, where the fuel is thinner Film applied and through a primarily assigned air rotation, which for example can be generated by an umbrella valve or a swirl channel, gradually in vapor form is detached, mixed with the air and then burned.

The purpose of the invention is the combustion chamber for after the above To train operating internal combustion engines so that by independent Adaptation of the mixture formation to the respective operating conditions special cold start auxiliary devices or corresponding external control measures become superfluous.

In the above-mentioned, known internal combustion engines is a Improvement of the cold start achieved by the fact that when starting up the cold machine, where the evaporation of the fuel on the combustion chamber wall is not yet sufficient or can not be done quickly enough, a larger proportion of the fuel immediately is injected into the combustion air to accelerate auto-ignition. The means for this are either changing the jet position of the nozzle by rotating it the same or changing the direction of rotation of the primary air rotation by adjustment for example an umbrella valve. However, these measures either require additional constructive designs of existing facilities or provision additional mechanical aids that can also be used with every starting process are. However, this makes the machine structurally and operationally more complicated and also more expensive to manufacture.

The invention takes a different approach while avoiding these deficiencies to improve the cold start conditions in the machines mentioned at the beginning, use is also made of the known basic idea mentioned, that you can improve the cold start that in the starting phase of the air-distributed Share of injected fuel is increased. The novelty of the invention is based, however, on the fact that no longer special mechanical aids and from the outside regular measures to be taken to achieve this effect are necessary, but that this effect is achieved through the appropriate design of the combustion chamber itself and the resulting special air flow in the combustion chamber is achieved. the Invention is based on the knowledge that when starting or starting the Machine due to the low speed in this operating phase and thus lower Air velocity for the primarily generated air rotation, the inflow conditions and the air density in the combustion chamber is different than in normal operation. The primary generated Air rotation has namely in the starting phase as a result of the lower at this point in time Air speed has an inflow tendency, which in its vortex formation around the The combustion chamber axis is relatively flatter, d. H. with a flatter one inclined to the axis of rotation Spiral vortex goes on as in full load or normal mode, where the primary air rotation at higher air speeds it takes the form of a very steep vortex spiral around the axis of the combustion chamber. According to this different course of the primary air rotation in the form of spiral vortices in the combustion chamber also takes place in each case the spread of the fuel film on the combustion chamber wall varies, d. H., At high speeds, the fuel is also in a steep spiral drawn more towards the bottom of the combustion chamber, while at lower speeds the Fuel film spreads along almost the entire wall of the combustion chamber or is pulled around on her. Thorough tests have confirmed this fact.

Further experiments have now shown that it is possible to use the different Vortex formation of the primary Air rotation in the combustion chamber at lower or high air speed to take advantage of a much larger one during a cold start Mix the fuel proportion directly with the air than in normal operation for the initiation of compression ignition is just allowed when the combustion chamber is designed so that it automatically influences the primary air rotation Secondary air flow is generated. Depending on the primary vortex formation during a cold start or full load, this secondary air flow will be different to the primary air rotation Have influence. .

The invention consists in that in the internal combustion engine mentioned at the beginning the pocket-like bulge arranged in the area of the combustion chamber opening takes the form one inclined towards the combustion chamber floor and approximately radially to the axis of rotation of the combustion chamber having extending channel, the projection of this channel onto the piston crown has a length that is greater than the radius of the combustion chamber, and the width of the Channel at the transition into the combustion chamber opening at least a quarter of this radius is, so that one with his through the bulge at the end of the compression stroke The axis of rotation is essentially perpendicular to the axis of rotation of the primary air rotation standing secondary air vortex arises, which is correspondingly weaker in the start-up state overcomes primary air rotation and thereby part of the rotating air mass out of the combustion chamber together with fuel held back by the combustion chamber wall displaced into the cylinder space above, on the other hand in normal or full load operation of the engine, the stronger primary air rotation that forms in the combustion chamber only marginally affected.

In this way, as tests have confirmed, it is possible to use im Cold start immediately a larger proportion of fuel without special aids to distribute in the hot combustion air and thereby the ignition during a cold start to accelerate. By allowing the secondary air vortex to a greater or lesser extent it is possible to increase or decrease the proportion of fuel distributed by air enlarge. The secondary air vortex is created through appropriate measures on the combustion chamber only allowed to the extent that fuel is carried up over the edge of the combustion chamber opening addition only occurs in the range of the starting speeds, then remains for the entire The desired wall distribution of the fuel is obtained in the remaining high speed range and thus also the resulting quiet running of the machine with low fuel consumption and at the same time high performance.

The arrangement of a pocket-like extension in the area of an im Engine piston arranged combustion chamber is known per se. It gets here, however aimed only at the applied injection and mixture formation process as to improve such, over the entire operating range of the engine. to this purpose is according to an older proposal that is not part of the state of the art the extension is designed so that the amount of air flowing into the combustion chamber at the extension point is larger than it is at a circular opening of the The combustion chamber would be the case at this point. The result of the expansion in the combustion chamber Excess air is then on the areas of the combustion chamber wall that are wetted with fuel directed. In this way, the fuel film on the combustion chamber wall becomes larger Amount of fresh air added than before, so that faster evaporation and mixing of the vaporized fuel is achieved with the combustion air.

The influence of the secondary air vortex can be according to a further feature the invention can still be controlled in that the combustion chamber floor has a flattening having. In the case of a combustion chamber designed as a sphere or an ellipsoid of revolution then the bottom of the same at a greater or lesser distance from the combustion chamber inwards Vertex of the floor curvature that is otherwise present in these combustion chamber shapes as flat surface formed. The measures mentioned will result from previous or later redirection of the secondary vortex by this the primary air rotation in their Overall vortex course more or less pushed upwards, so that with a cold start depending on the pre-setting using the specified measure, more or less fuel is displaced out of the combustion chamber.

In the drawing, the invention is based on a preferred embodiment shown. Here, Fig. 1 shows an injection engine with an im Rotational body-shaped combustion chamber arranged in the piston crown, FIG. 2 is a top view on the piston of a machine according to FIG. 1, FIG. 3 shows the schematic representation of the Generation of a primary air rotation in the cylinder of an internal combustion engine an umbrella valve, FIG. 4 is a diagram of the primary air rotation in the combustion chamber during start-up of the machine in the event that no secondary vortex is provided, FIG. 5 is a diagram the primary air rotation in the combustion chamber at full load in the event that no Secondary vortex is provided, Fig. 6 is a diagram of the secondary air vortex generated according to the invention in the combustion chamber alone, d. H. without considering the primary air rotation, Fig. 7 shows a diagram of the resulting air vortex in the combustion chamber during a cold start Pushing up the primary air rotation through the secondary vortex along with the resulting conditional displacement of fuel from the combustion chamber is also indicated.

In Fig. 1, 1 is the piston, just in the area of its top dead center position, of an internal combustion engine, indicated only by the inner cylinder jacket 2 and the cylinder head boundary line 3, in which the fuel is sprayed onto the combustion chamber wall in a known manner and in vapor form from the combustion chamber wall by an associated air rotation is replaced. The combustion chamber provided in the piston crown, which is shaped like a body of revolution and constricted at its opening 5 , is denoted by 4. The combustion chamber 4 has a pocket-like bulge 6 in the region of the combustion chamber opening 5 , into which the opening 7 a of the injection nozzle 7 also engages in the position shown. From the nozzle orifice 7a, a fuel jet 8 or more such fuel jets are sprayed onto the combustion chamber wall 9 in a known manner in such a way that the fuel spreads as a thin film on the combustion chamber wall. A screen valve 110 is arranged in the cylinder head, by means of which a primary air rotation is generated in the cylinder, which is indicated in FIGS. 2 and 3 by the arrow lines 11. If only the umbrella valve 10 were solely responsible for its formation, this primary air rotation would continue towards the combustion chamber 4 in a vortex, the course of which for the start-up phase in FIG. 4 with 12 and for normal or full load operation in FIG 5 is indicated schematically at 13.

As can be seen from FIG. 4, when the machine is started or started, the angle of inclination α, β of the primary air rotation relative to the axis of rotation A -A is large for the air vortex 12 and the rotary vortex 12 therefore has a flat spiral. 5, however, shows the vortex formation in full load operation, where due to the high air speed in this work phase, the air twisting vortex113 runs spirally to the axis of rotation AA towards the piston head and therefore the inflow vortices a1, ßl are correspondingly much smaller.

In the area of the combustion chamber opening 5, the pocket-like bulge has the shape of a channel 6 inclined towards the combustion chamber floor and running approximately radially to the combustion chamber axis of rotation AA. Here, the projection of this channel onto the piston head is of a length that is greater than the radius r of the combustion chamber and the width b of the channel at the transition into the combustion chamber opening is at least a quarter of this radius. When the piston approaches its top dead center position, a secondary air vortex 14 is generated, the flow course of which in the combustion chamber 4 is indicated schematically in FIG. 6 by the curve S. As can be seen from this figure, the axis of rotation B of the secondary air vortex 14 is perpendicular to the axis of rotation A-A of the primary air rotation 12 and 13 shown in FIGS. 4 and 5 , always appear simultaneously and will therefore always overlap. By suitable dimensioning and direction of the pocket-like bulge 6, care is now taken that the secondary air vortex 14 can only occur so strongly that it only overcomes the weaker primary air vortex 12 in the start-up or start-up phase and pushes it upwards, as shown in FIG 7 is shown at 12a. As a result, a larger proportion of fuel is inevitably kept from contact with the combustion chamber wall and displaced into the cylinder chamber 15 above the combustion chamber opening 5, as is indicated in FIG. 7 by the dots 16. Since, on the other hand, the pocket-like bulge 6 is dimensioned in such a way that only the weaker and flatter air vortex 12 of the start-up phase is overcome by the secondary air vortex 14, the result is inevitably without further aids or external intervention that the much stronger and steeper rotating vortex 13 (Fig. 5) is no longer overcome by the secondary vortex 14, so that the latter only has an effect in the combustion chamber 4 itself. At full load, the full wall distribution of the fuel for the best possible implementation of the injection and mixture formation process on which the invention is based is thus established automatically. According to further features of the invention, the influence of the secondary vortex 14 can be controlled by keeping the distance h of the combustion chamber floor from the combustion chamber opening 5 larger or smaller. In the case of a combustion chamber configured as a sphere or ellipsoid of revolution, as shown in the example, the combustion chamber floor is advantageously configured as a flat surface 17 at a greater or lesser distance from the apex of the otherwise existing floor curvature.

The invention thus achieves the advantage in an internal combustion engine of the type assumed at the beginning for cold start and full load operation without any external intervention to automatically bring about the desired mixture formation, whereby the transition from cold start to full load operation is also automatic Adaptation to the required air or wall distribution of the fuel he follows.

Claims (3)

PATENT CLAIMS: 1. Air-compressing, self-igniting internal combustion engine with a combustion chamber in the shape of a rotary body and constricted at its opening, which is arranged in the piston and has a pocket-like bulge in the area of its opening, and with an injection nozzle that feeds the fuel either through the constricted opening of the combustion chamber or through the pocket-like Bulge splashes through against the combustion chamber wall, where the fuel is applied as a thin film and gradually detached in vapor form by a primarily associated air rotation, mixed with the air and then burned, characterized in that the bulge has the shape of an inclined towards the combustion chamber floor and approximately having a channel (6) extending radially to the combustion chamber axis of rotation (AA), the projection of this channel onto the piston head having a length which is greater than the radius (r) of the combustion chamber. and the width (b) of the channel at the transition into the combustion chamber opening is at least a quarter of this radius (r), so that through the bulge at the end of the compression stroke, one with its axis of rotation (B) to the axis of rotation (AA) of the primary air rotation (12, 13) essentially vertical secondary air vortex (14) arises, which overcomes the weaker primary air rotation (12) in the start-up state and thereby displaces part of the rotating air mass together with fuel held by the combustion chamber wall out of the combustion chamber into the cylinder chamber above Normal or full load operation of the machine only insignificantly influences the stronger primary air rotation (13) that forms in the combustion chamber. 2. Injection internal combustion engine according to claim 1, characterized in that the Combustion chamber bottom has a flattening. 3. Injection internal combustion engine according to claims 1 and 2 with a combustion chamber designed as a sphere or ellipsoid of revolution, characterized in that the flattening is designed as a flat surface (17) .