DD155259A1 - PISTON-CONTROLLED TWO-STROKE INJECTION MOLDING MACHINE - Google Patents

Abstract

The invention relates to a two-stroke engine with a combustion chamber in the cylinder head, which is arranged transversely to the spool and in which a Einspritzduese and a Zuendquelle muenden and with inlet and Auslasskanaelen and with a transverse to the cylinder axis rotating swirl flow. The aim is to improve the mixture formation in all load ranges, in order to constantly ensure a safe ignition and burning of the charge, the task is to adapt the combustion chamber shape and position, Zuendquellen- and Stahlandrrdnung the charge movement. According to the invention, this is achieved by means of a combustion chamber trough arranged transversely to the purging flow in the center of the cylinder head or arranged transversely to it, which consists of three combustion chamber parts and, in its projection on the piston head, has a shape adapted to the contour of the injection jet.

Description

Title of the invention:

Piston-controlled two-star injection internal combustion engine

Field of application of the invention:

The invention relates to a piston-controlled two-stroke injection internal combustion engine with a combustion chamber located in the cylinder head, which is arranged transversely to the purge flow and into which an injection nozzle and an ignition source opens and with overflow and exhaust ports and with a transverse to Zylinderacb.se rotating swirl flow, wherein the fuel accumulated in the Brennraunimulde largest and by, the rotating swirl flow is removed ·

Characteristic of the known technical solutions:

Previously known from DE-P3 713-618 is a self-igniting, air-compressing four-stroke internal combustion engine, in which the combustion chamber is arranged predominantly sum in the piston, wherein the opening to the combustion chamber part in the cylinder head has no significant throttle effect * The fuel is towards the end of the compression stroke the injected into the cylinder head inclined to the piston head injector distributed in the entire combustion chamber. Towards the end of the compression stroke 'is the combustion air in the larger piston combustion chamber part and the smaller conical Bremrautateil the cylinder head. Both

Parts together result in a pear-shaped cavity adapted to the shape of the fuel jet. In this solution, without intentional Wandanlagerung of the fuel, a homogeneous fuel-air mixture aspired facilities for generating.bzw. Exploitation of charge flows are not mentioned «has a disadvantage that the pear-shaped cavity ge only in the vicinity of the piston position of top dead center '^; Idet is what late injection is necessary because otherwise the jet of fuel partly impinges on the piston crown over the piston recess. This disadvantage arises in particular when using the aforementioned combustion chamber arrangement in two-stroke internal combustion engines, in which the injection must generally be very early · Previously known by DE-PS 966 044, a method for operating a two-stroke internal combustion engine with disk-shaped combustion chamber, wherein the Fuel z. T. is injected into the circular swirling fresh air and ignited at the nearby ignition device forming a flame front, wherein the vortex is further injected gradually to maintain the combustion continuously and spread. The main concern of this combustion process is a significant reduction in the tendency to knock of the fuels used.

The disadvantage is that due to the relatively late injection, the mixture preparation time is very short and so at full load, the combustion of the fuel takes place only incomplete

Furthermore, previously known is an injection internal combustion engine with a cylindrical, transverse to the cylinder axis combustion chamber according to DE-PS 894 338, in which the fuel is injected in the direction of the longitudinal axis. At the piston head and cylinder cover is in each case a gradation, which cover both gradations «In the range of this gradation, the combustion chamber from the piston crown

or cylinder cover bottom limited tangentially. The squeezing effect of the gradation produces a swirling motion in the combustion chamber, which results in a good mixture of fuel and air in principle.

In this solution, a homogeneous fuel-air mixture is sought without intentional Wandanlagerung of the fuel. The disadvantage is that the crushing effect due to the low in height gradation begins shortly before top dead center and thus the time for the mixture formation is very short. Furthermore, the DS-AS 1 900 404 discloses a piston-controlled, mixture-compressing two-stroke internal combustion engine with direct fuel injection against the air flow and with a cylinder head combustion chamber receiving an injection nozzle and a spark plug. This combustion chamber consists of a cylinder head projection which covers the edge region of the piston and has a recess adjacent thereto. The fuel injection takes place in an edge layer of the air flow deflected on the cylinder head projection in the direction of the combustion chamber wall opposite the injection nozzle. The in the depression through. Deflection Retained fuel is blown by the inflowing air as a layer in the direction of the ignition and ignited the resulting fuel-air mixture »The depth of the combustion bowl increases in the direction of the eddy current. The fuel injected into it is deflected towards the cylinder head wall and the lowest point of the combustion chamber is assigned to the incoming mixture vortex. · The width of the combustion bowl is greater than its depth, and opposite the cylinder head projection, a sharp terminal edge of the burner trough is in the range of the mixture vortex. With this solution, a rich fuel-air mixture is to be formed in the region of the spark plug, while in the remaining cylinder chamber a relatively lean mixture is present; The disadvantage is that on a relatively small

Brennraumfläche a relatively large amount of fuel is deposited. This is particularly unfavorable for large injection quantities to achieve high energy densities.

Previously known by DD-PS 129 352 arranged in the cylinder head combustion chamber for two-stroke internal combustion engine with fuel injection. The combustion chamber consists of a transversely to the purge stream above the outlet channel arranged, trough-shaped recess into which the fuel is injected »It should be achieved by means of improved design and arrangement of the combustion chamber and the injector combustion during each working cycle with high efficiency and minimal emission of pollutants. The combustion chamber is arranged above the outlet channel and has a semicircular cross-section which is rectilinear to the pinch surface and forms a sharp edge at the transition, the injection nozzle is arranged at an angle to the axis of the combustion chamber, so that the beam cone occurring on the wall portion of the scavenging air is directed ·

A disadvantage of this arrangement is a slight swirling motion in the combustion chamber, whereby in certain speed ranges, the fuel is removed only insufficient and thus does not participate in the combustion. This increases the proportion of unburned hydrocarbons in the exhaust gas of the internal combustion engine

Aim of the invention;

The mentioned disadvantages of the previously known two-stroke injection internal combustion engines and mixture-compressing internal combustion engines are to be eliminated, whereby by means of qualitatively improved mixture formation the ignition conditions of the mixture are to be optimized in order to reduce the emission of unburned hydrocarbons in the exhaust gas.

Explanation of the essence of the invention:

The object of the invention is to find an appropriate combustion chamber shape and location in the cylinder head of a charge stratification engine for an internal combustion engine of the type described above, which ensures reliable ignition and perfect combustion of a lean fuel-air mixture through improved mixture formation.

According to the invention, this object is achieved by the combination of the following known features:

- Arrangement of the combustion bowl in the middle of the cylinder head or slightly offset in the direction of the rising purge stream;

- A in their projection on the piston head substantially the contour of the injection jet adapted shape of the combustion chamber trough, which has a quarter-spherical combustion chamber part as the end part.

This achieves an improved removal of the sprayed on the most part of the quarter-spherical combustion chamber part fuel using a rotating swirl flow, which is formed in the transverse to the indicated purge flow combustion bowl due to the Spülstromverlaufes and the compression. At partial load, the presence of an ignitable mixture at the ignition source is ensured. This is mainly a reduction of the hydrocarbon emission and fuel consumption and an improvement of the running behavior over the entire speed range achieved. Advantageously, the combustion bowl from three different in volume combustion chamber parts, while the viortelkugelförmige and the Kegelsturapfabachnittfcrmige combustion chamber part together two to four times the volume of the cylinder from se Imittförmigen Brennrauinteiles on. This ensures a favorable charge distribution for the combustion process.

Advantageously, it also has an effect if the ignition source is arranged in the truncated cone-shaped part or in its transition to the quarter-spherical part of the combustion chamber recess. In the abovementioned region, the formation of air is preferably carried out by ablating the fuel sprayed in the direction of the swirl axis, whereby in each operating state Internal combustion engine an ignitable mixture is ensured at the ignition source. In particular, with a slight offset of the brake chamber recess away from the cylinder head center in the direction of the ascending purge flow, a continuous widening of the distance from the piston crown to the cylinder head at top dead center of the piston in the direction of the combustion chamber recess is expedient. Both serve to generate the combustion chamber The axis of the injection nozzle can be inclined by 90 ° to the axis of the cylinder. The vortex undertakes the removal of the fuel sprayed on the quarter-spherical or conical-frustum portion-shaped combustion chamber part in the axial direction of the vortex · An attachment of the injection nozzle inclined by less than 90 degrees to the cylinder axis reduces the proportion of fuel to be applied to the two rear combustion chamber parts.

Embodiment of the invention:

Exemplary embodiments of the invention will be described with reference to drawings.

Fig. 1 arranged in the cylinder head combustion chamber of the piston-controlled two-stroke injection internal combustion engine transverse to the rising purge flow with an ignition head located in the cylinder head at piston position in the bottom dead center

Fig. 2 as Figure 1 shows the combustion bowl when piston position outlet channel closed. A swirling flow, which rotates ac- celerately across the cylinder, is formed, which causes a vortex in the combustion bowl when it is compressed, the axis of which coincides with the combustion chamber longitudinal axis;

1 shows the combustion chamber trough composed of 3 parts and the slightly inclined injection nozzle with the injection jet contour in the piston position at bottom dead center;

4 shows the shape of the combustion chamber recess from below with central position of the combustion bowl and the ignition source, including the injection jet contour, which is clearly adapted to the contour of the frusto-conical and Viertelkugelförraigen combustion chamber part.

FIG. 5 shows a variant of FIG. 1 and FIG. 3 shows the off-center arrangement of the ignition source in the transition from the truncated-cone-shaped section to the quarter-spherical combustion chamber section and the arrangement of the injection nozzle inclined by 90 ° relative to the cylinder axis;

FIG. 6 shows a variant of FIG. 4 according to section A-A in FIG. 5; FIG.

FIG. 7 shows a variant of FIG. 4 with the scavenging flow away from the cylinder axis in the direction away from the focal point.

In the piston-controlled two-stroke Sinspritzbrennkraftmaschine shown in FIG. 1 to 7 with a combustion chamber 2 located in the cylinder head 3, which is arranged transversely to the purge flow 4 and into which an injection nozzle 15 and an ignition source 1 opens and with overflow and exhaust ports 6, 7th and with a swirling flow 10 rotating transversely to the cylinder axis, the fuel is conveyed to the most part in the quarter-spherical combustion-chamber part 11, to a small extent in the truncated-cone-shaped combustion chamber.

Part 12, attached as a thin film. The arrangement of the combustion chamber trough 2 substantially adapted in its shape to the projection of the injection nozzle onto the piston head takes place in the center of the cylinder head 3. The bottom of the piston 8 has the usual curved shape. The swirl flow 10 produced in the case of two-stroke engines from the scavenging flow path 4 remains approximately the same during compression. The rotating swirl flow 10 leads to the formation of the vortex 9 in the combustion chamber trough 2. This has the task of gradually dissolving the fuel, which is sprayed onto the combustion chamber parts 11 and 12, from the walls and fed to the combustion hearth. The arrangement of the ignition source 1, in particular in its variant 1a, ensures that at low and medium loads, where the fuel is injected just before the ignition and in small quantities, an ignitable mixture is present at the ignition source 1.

The shape of the individual combustion chamber parts 11; 12 and 13 and the proportion of the two to four times larger volume of the combustion chamber parts 11 and 12 with respect to the cylinder portion-shaped combustion chamber part 13 ensures, in conjunction with the position of the ignition source 1 and 1a and the position of the injection nozzle 15 and 15a, an economical combustion of a lot lean mixtures in the partial load range and a good transition in the performance of the internal combustion engine to the full load range with a small proportion of unburned hydrocarbons in the exhaust gas.

The transition from the combustion chamber walls to the cylinder head surface is made sharp-edged to support the vortex formation in the combustion bowl. In the combustion chamber trough displaced slightly away from the cylinder head center in the direction of the rising purge flow, a continuous increase in the distance from the piston crown in its upper dead center position to the cylinder head bottom surface in the direction of the combustion chamber trough is provided.

Claims (6)

Invention claim: 1. Piston-controlled Zweitalct injection internal combustion engine with a combustion chamber located in the cylinder head, which is arranged transversely to the purge flow and into which an injection nozzle and an ignition source and with overflow and exhaust ports and with a transverse to the cylinder axis rotating swirl flow, characterized by the following per se known features : - Arrangement of the combustion bowl (2; 16) in the middle of the cylinder head (3) or slightly offset in the direction of the rising purge stream (4 ·); a shape of the combustion chamber trough (2; 16) adapted in its projection onto the piston bottom substantially in the contour of the injection jet (17), the latter having a quarter-spherical combustion chamber part (11) as the final part. 2. Piston-controlled two-stroke injection internal combustion engine according to item 1, characterized in that the combustion chamber trough (2) consists of three different in their volume combustion chamber parts (11; 12; 13), thereby, the quarter-spherical (11) and truncated cone abschnittf örmige Brenntaumteil (12) together two to four times the volume of the cylinder-section-shaped combustion chamber part (13). 3. Piston-controlled two-stroke Einspritzbrernikraftmaschine according to item 1, characterized in that the ignition source (1) in the truncated cone-shaped combustion chamber part (12) or in its transition region to the quarter-spherical combustion chamber part (11) is arranged (1 a). 4- · Piston-controlled two-stroke injection internal combustion engine according to item 1, characterized in that the injection nozzle (15) is arranged inclined to the cylinder axis by 90 ° or less (15a). 5 · piston-controlled two-stroke injection internal combustion engine according to. Item 1, characterized in that the transition from the combustion chamber walls to the cylinder head bottom surface is sharp-edged. 6 · piston-controlled two-stroke injection internal combustion engine according to item 1, characterized in that the distance between the piston head and the cylinder head bottom surface at a piston position at top dead center in the direction of the combustion chamber trough (2) steadily increases _β For this 4 pages drawings