RU2343296C1 - Combustion chamber in internal combustion engine (versions) - Google Patents

Abstract

FIELD: motors and pumps.

SUBSTANCE: invention relates to piston-type internal combustion engines. Combustion chamber of internal combustion engines is limited with cylinder wall, lid and piston and provided with additional air storage chamber, which is connected with combustion chamber by the nozzle. The additional air storage chamber is located in piston. The nozzle axis is directed through the combustion chamber centre. Besides, the volume of additional air storage chamber is 20-30% of combustion chamber. The air storage chamber is made of low heat-conducting materials, e.g. nickel steel or ceramic materials. The invention provides for consideration the versions, when additional air storage chamber is located in cylinder lid and nozzle axis is directed to the piston centre through combustion chamber centre. The other version assumes that additional air storage chamber is detached from cylinder lid and nozzle axis is directed across the cylinder and combustion chamber.

EFFECT: intensification of fuel mixing up with air during fuel burning, completeness of fuel burning, improvement of engine economic feasibility and service life, reduction of exhaust gas toxicity and opacity at all engine operation modes.

3 cl, 4 dwg

Description

The invention relates to piston internal combustion engines, and in particular to engines with a combustion chamber, divided into two parts, and can find application in carburetor and diesel internal combustion engines.

It is almost impossible to obtain a high-quality mixture of fuel with air with existing mixing devices. At best, the fuel enters the combustion chamber in the form of droplets the size of one micron, and in this drop are millions of molecules of carbon and hydrogen. These drops must be evaporated, thermally decomposed into individual atoms and mixed with air. A drop of fuel at this time is a sphere with increased pressure inside a sphere consisting of gaseous hydrogen and atomic non-gaseous carbon. At the same time, ideal conditions are created inside the sphere for the formation of carbon black and possibly very small diamonds, which partially adhere to the oil film on the cylinder wall and gradually turn the oil in the engine crankcase into a dark wiping paste based on graphite and very small diamonds. With good mixing and some excess air, all this at the last stage of fuel combustion can burn out and the engine will show high efficiency. However, fuel in the volume of the combustion chamber of a diesel engine is distributed with great unevenness, therefore, for a high-quality combustion process, it is necessary to use high coefficients of excess air equal to 4.70-2.20 (Lebedev O.N., Somov V.A., Kalashnikov S.A. Internal combustion engines of river vessels. M.: Transport, 1990, p. 108).

For diesel engines with a piston diameter of less than 150 mm, semi-separated and divided combustion chambers are used, which provide good mixing of fuel with air with an air excess ratio of 1.5-1.7 for semi-separated combustion chambers and 1.25-1.35 for divided combustion chambers ( Lebedev, O.N., Sotov, V.A., and Kalashnikov, S.A., Internal Combustion Engines of River Ships, Moscow: Transport, 1990, pp. 114, 116, 117). However, engines with these combustion chambers have increased fuel consumption due to additional heat and aerodynamic losses (when air and gases flow from one cavity to another), as well as increased heat loss due to the large heat transfer surface.

The closest analogue is a combustion chamber with precamera mixture formation (Lebedev ON, Somov VA, Kalashnikov SA Internal combustion engines of river ships. M: Transport, 1990, p. 117), in which the volume compression is divided into the main chamber and the chamber, which is placed in the cylinder cover. The cameras are interconnected by several channels. The pre-chamber has a relatively small volume of 25-40% of the combustion chamber. The working process of pre-chamber diesel proceeds as follows. In the process of compression, air from the over-piston space through the connecting channels enters the pre-chamber. This overflow occurs at significant pressure drops (300-600 kPa) and at high speeds, as a result of which an intense disordered movement of the air charge occurs in the prechamber. Fuel is injected towards the air flow, while the fuel mixes well with air, ignites and partially burns. The pressure in the pre-chamber rises sharply and the mixture of fuel, combustion products and air begins to be ejected into the main chamber, while the pressure in the pre-chamber drops sharply. In the main chamber at this time, intense jet mixing of the medium flowing from the prechamber with air occurs and the main part of the fuel is burned.

The disadvantages of engines with separated combustion chambers are as follows:

- low starting properties;

- increased fuel consumption;

- the design of the cylinder cover is complicated, which is associated with the placement of an additional chamber in it.

For this reason, mixture formation in divided combustion chambers has found application in small-sized, high-speed 4-stroke diesel engines. In 2-stroke diesel engines, these methods of mixture formation are not used due to the difficulty of cleaning additional chambers from exhaust gases.

The task is to increase the intensity of mixing fuel with air during combustion in order to ensure complete combustion of fuel and, accordingly, increase fuel efficiency and engine life, increase the average indicator pressure of the cycle, and reduce exhaust smoke at maximum power.

This problem is solved as follows.

In accordance with the prototype, the combustion chamber of the internal combustion engine, limited by the cylinder wall, the cylinder cover and the piston, has an additional air storage chamber.

According to the invention:

- according to the first embodiment, the air storage chamber is located in the engine piston and connected to the combustion chamber by the nozzle, the nozzle axis being directed through the center of the combustion chamber, and the volume of the air storage chamber is 20-30% of the volume of the combustion chamber, while the air storage chamber made of a material with low thermal conductivity, for example, nickel-plated steel or ceramic materials;

- according to the second embodiment, the chamber-accumulator is located in the cylinder cover and is connected by a nozzle to the combustion chamber, the nozzle axis being directed through the center of the combustion chamber, and the volume of the air-accumulator chamber is 20-30% of the volume of the combustion chamber, while the air-chamber chamber is made from a material with low thermal conductivity, for example, from nickel-plated steel or ceramic materials;

- according to the third embodiment, the air storage chamber is located separately from the cylinder cover and is connected by the nozzle to the combustion chamber, the nozzle axis being directed across the cylinder and the combustion chamber, and the volume of the air storage chamber is 20-30% of the volume of the combustion chamber, while the battery chamber air is made of a material with low thermal conductivity, for example, nickel-plated steel or ceramic materials.

Further, the invention is illustrated by drawings, which depict:

- figure 1 - combustion chamber with a piston at top dead center with an additional camera-accumulator of air placed in the piston;

- figure 2 explains how the additional air storage chamber according to the first embodiment creates a vortex that mixes the fuel with air at the beginning of the working stroke;

- figure 3 - placement of an additional camera-air accumulator in the cylinder cover of a 2-stroke engine with loop blowing;

- figure 4 - placement of an additional camera-air accumulator separately from the cylinder cover of a 4-stroke engine.

The device and operation of the combustion chamber

In the cylinder 1, the over-piston space is connected to the additional chamber-air accumulator 2 by a nozzle 3. The combustion chamber 4 is located in the cylinder cover 5. The additional chamber-air accumulator is placed in the piston 6 (Figs. 1, 2).

The combustion chamber operates as follows:

when the piston 6 is at bottom dead center and in the cylinder 1 the cycle of purging the cylinder 1 with a fresh charge of air ends, the air pressure in the above-piston space and in the additional air storage chamber are equal.

In the process of compression, air from the over-piston space through the nozzle 3 flows into the additional chamber 2, where it accumulates. At the end of compression, fuel is injected into the combustion chamber 4, where it ignites and the pressure and temperature of the gases increase sharply in the combustion chamber 4, while the burnt fuel products will flow into the additional chamber 2. Under the action of high gas pressure, the piston 6 will go down and the stroke of the stroke will begin. The combustion chamber 4 will increase in volume, the pressure in the combustion chamber will decrease and the moment will come when the gas pressures in the combustion chamber 4 and the air pressure in the additional air storage chamber are equal. Soon, the pressure in the additional chamber 2 will be higher and the air accumulated in the additional chamber 2, through the nozzle 3, will go through the center of the combustion chamber 4, rest against the center of the cylinder cover 5, and diverge along the edges of the combustion chamber 4 and the free part of cylinder 1. This creates a vortex torus (Figure 2) from gases heated in the combustion chamber 4, and air from the additional chamber 2. The mixing of the gases will be very intense and will contribute to complete combustion of the fuel with a small excess of air. The air supply from the additional chamber-accumulator of air 2 will begin when the combustion process has not yet been completed, and will continue throughout the entire stroke. However, the main part of the air leaves the additional chamber 2 before the piston comes to the middle position, while ensuring complete combustion of the fuel.

The operation of the combustion chamber of FIG. 3 differs from the above-described operation of the chamber of FIG. 1 in that the air from the additional chamber 7 located in the cylinder cover 8, through the nozzle 9 will go to the center of the piston 10, then to the wall of the cylinder 11 and into the combustion chamber 12 creating a vortex of gases in the form of a torus with the direction of rotation indicated by arrows.

The operation of the combustion chamber of FIG. 4 differs from the above-described operations of the combustion chambers of FIG. 1 and FIG. 3 in that the additional air storage chamber 13 is located separately from the cylinder cover 14 as an independent part. The nozzle 16 enters the combustion chamber 15, which even during the beginning of the working stroke creates a stream of air across the cylinder 17, forming two vortices in the combustion chamber 15. These two vortices rotate from the air stream: one to the left and the other to the right, providing fuel mixing and air during the combustion process.

Placing an additional chamber in the piston causes an increase in thermal stress in the piston; therefore, it can be assumed that the additional chamber should be made of nickel steel having low thermal conductivity, or of ceramic materials. Some firms have experience using ceramics in internal combustion engines.

The technical result of the invention:

- increase the intensity of mixing fuel with air during combustion;

- ensuring the completeness of fuel combustion;

- increase engine efficiency;

- increase engine life;

- reduction of toxicity and smoke of exhaust gases in all operating modes of the internal combustion engine.

Claims (3)

1. The combustion chamber of the internal combustion engine, limited by the cylinder wall, cylinder cover and piston, having an additional air storage chamber connected by a nozzle to the combustion chamber, characterized in that the additional air storage chamber is located in the piston, and the axis of the nozzle is directed through the center of the chamber combustion, while the volume of the additional air-storage chamber is 20-30% of the volume of the combustion chamber, moreover, it is made of a material with low thermal conductivity, for example, nickel steel or ceramic materials. 2. The combustion chamber of the internal combustion engine, limited by the cylinder wall, cylinder cover and piston, having an additional air storage chamber connected by a nozzle to the combustion chamber, characterized in that the additional air storage chamber is located in the cylinder cover, and the axis of the nozzle is directed through the center the combustion chamber to the center of the piston, the volume of the air storage chamber being equal to 20-30% of the volume of the combustion chamber, moreover, it is made of a material with low thermal conductivity, for example, nickel steel or ceramic FIR materials. 3. The combustion chamber of the internal combustion engine, limited by the cylinder wall, cylinder cover and piston, having an additional air storage chamber connected by a nozzle to the combustion chamber, characterized in that the additional air storage chamber is made separately from the cylinder cover, and the axis of the nozzle is directed across a cylinder and a combustion chamber, the volume of the air storage chamber being equal to 20-30% of the volume of the combustion chamber, moreover, it is made of high-strength material with low thermal conductivity, for example, nickel with Ali, or ceramic materials.

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