RU2546933C1 - Method of operation of rotary internal combustion engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: method of operation of rotary internal combustion engine with epitrochoidal working chamber and trihedral rotor is implemented out by supply into the working chamber of fresh fuel-air mix and hydrogen with the pre-set air excess coefficient. Hydrogen is supplied into the zone adjacent to back top of the rotor, at the moment coinciding with spark supply to the burning-up spark plug.

EFFECT: increase of completeness of combustion of fuel-air mix in the rotor and piston engine at a smaller consumption of utilized hydrogen.

7 dwg

Description

The invention relates to mechanical engineering, in particular to engine building, and is a method of operating a rotary piston internal combustion engine.

The main advantages of RPD over traditional reciprocating engines are smaller overall dimensions and better indicators of balance and metal consumption. However, RPDs still cannot compete with the latter, since they have a slightly higher specific fuel consumption and an increased content of unburned hydrocarbons in the exhaust gases.

The reason for these shortcomings is mainly incomplete combustion of the air-fuel mixture near the rear of the rotor top. The propagation of the flame front towards this part of the combustion chamber is prevented by the unidirectional movement of the air-fuel mixture due to the rotation of the rotor. An effective solution to this problem is the addition of hydrogen to the main air-fuel mixture. The increased concentration of hydrogen, which has high chemical activity and heat of combustion, allows you to increase the speed of flame propagation in the air-fuel mixture towards the rear of the rotor.

A known method of operation of an internal combustion engine, which consists in supplying hydrogen (copyright certificate SU No. 1206458, IPC F02B 43/08, published 01/23/1986) by connecting a hydrogen source to the inlet using a pipeline with a regulating shut-off element, according to which at the beginning start-up, the first portion of hydrogen is outside the ignition in concentration, while creating a rich hydrogen-air mixture (more than 74.2% of hydrogen by volume). This method is aimed at combating backflashes, however, when the engine is purged, a significant amount of hydrogen will be lost, and there is also no possibility of dosing small cyclic hydrogen supplies, which increases the consumption of used hydrogen.

There is a known method of powering an internal combustion engine, which consists in supplying hydrogen under a certain discharge through a check gas-dynamic valve into the inlet channel (patent RU No. 2006608, IPC F02B 43/08, published January 30, 1994). The disadvantage of this method is the difficulty of controlling the gas-dynamic valve, depending on the operating mode of the engine, which excludes the possibility of supplying the right amount of hydrogen, resulting in a significant increase in its consumption.

A known method of operation of an internal combustion engine (patent RU No. 2123121, IPC F02B 5/02, F02B 43/12, published 10.12.1998), comprising supplying a fuel-air mixture to the combustion chamber, compressing it, supplying hydrogen to the electrode area of the spark plug by a pulse by time with spark discharge, and ignition. In this case, for the effective ignition of the air-fuel charge, the ratio of the mass of hydrogen to the mass of fuel does not exceed 0.001 in the regime of no more than 2/3 of the maximum load. However, due to the specifics of the charge movement in a rotary piston engine, the addition of hydrogen to the area of the spark electrode does not solve the problem of burning the air-fuel mixture at the rear apex of the rotor. The disadvantage of the described method is the need to use non-standard spark plugs.

The closest (prototype) to the claimed invention is a method of operating a rotary piston internal combustion engine (copyright certificate SU No. 1097815, IPC F02B 55/10, published June 15, 1984) with an epitrochoid working chamber and a trihedral rotor by supplying a fresh air-fuel mixture into the working chamber with a given coefficient of excess air in two streams: the first stream delivers a hydrogen-air mixture and is directed parallel to the end surface of the rotor, and the second feeds a hydrocarbon-air mixture and is directed perpendicular this surface. As a result, the exhaust gas toxicity is reduced, however, the resulting air-fuel mixture with hydrogen additives is located mainly at the front apex of the rotor, which leads to an increased consumption of used hydrogen.

The technical result of the invention is to increase the completeness of combustion of the fuel-air mixture in the RPM at a lower consumption of hydrogen and, accordingly, to reduce the specific consumption of the main hydrocarbon fuel and the emission of toxic substances with exhaust gases.

The technical result is achieved by the fact that in the method of operation of a rotary piston internal combustion engine with an epitrochoid working chamber and a trihedral rotor by supplying a fresh air-fuel mixture and hydrogen with a given coefficient of excess air to the working chamber, hydrogen is supplied to a zone adjacent to the rear apex of the rotor, at the time coinciding with the supply of a spark to the afterburning spark plug.

When hydrogen is supplied in this way, a hydrogen-enriched air-fuel mixture enters precisely into the zone in which the flame front propagates against the directional movement of the air-fuel mixture due to the rotation of the rotor. Due to the higher flame propagation velocity in the hydrogen-enriched air-fuel mixture, the flame front has time to reach the rear apex of the rotor before opening the outlet window. As a result, the completeness of combustion of the fuel-air mixture increases, which, in turn, leads to a decrease in the consumption of hydrogen used and at the same time to a decrease in the specific consumption of the main hydrocarbon fuel.

The invention is illustrated by drawings, which depict:

figure 1 - diagram of a rotary piston engine at the beginning of the intake stroke;

figure 2 is a diagram of a rotary piston engine at the time of starting the supply of hydrogen at the intake stroke;

figure 3 is a diagram of a rotary piston engine at the end of the intake stroke;

figure 4 - diagram of a rotary piston engine at the beginning of the combustion process;

figure 5 is a picture of the propagation of flame fronts, depending on the amount of hydrogen addition;

Fig.6 is a comparison of the consumption of hydrogen as a percentage of the bulk of the fuel under various conditions of hydrogen supply;

figure 7 - dependence of the proportion of unburned fuel from the load mode of the engine without the addition of hydrogen.

The rotary piston engine operating according to the proposed method (Figs. 1-4) comprises a stator 1 with an epitrochoid working chamber 2 with a trihedral rotor 3 located therein. The rotor is connected to an epitrochoid working chamber of the stator of each of its three peaks 4, 5, 6 while creating three separate working chambers 7, 8, 9. Inlet covers are located in the side cover 10. An exhaust window 11 is made in the stator and two spark plugs are placed: the leading candle ″ L ″ 12 and the afterburning candle ″ T ″ 13.

The method of operation of a rotary piston engine is as follows.

When the rotor 3 moves from the top dead center at the intake stroke in the working chamber 7, the inlet windows 10 open and through them the flow of the mixture of air and the main hydrocarbon fuel begins (Fig. 1). With further movement of the rotor 3 in the working chamber 7 at the inlet stroke, hydrogen begins to add hydrogen to the mixture of air and the main hydrocarbon fuel at a point in time that coincides with the supply of a spark to the afterburning spark plug ″ T ″ 13 in the working chamber 8 next to the rotor (Fig. 2). Further along the rotor 3, the rear top of the rotor 5 of the working chamber 7 overlaps the inlet windows 10 (Fig.3), the supply of the main hydrocarbon fuel, air and hydrogen is stopped and the working mixture is compressed. At the end of the compression stroke near the dead center, high voltage pulses are supplied to the leading candle ″ L ″ 12 and the afterburning candle ″ G ″ 13 to ignite the mixture. In this case, the air-fuel mixture with hydrogen additives is located in the zone between the rear apex of the rotor 5 and the “T ″ 13 afterburner, i.e. in the area adjacent to the rear apex of the rotor (figure 4), which leads to complete combustion of the main hydrocarbon fuel. Then there is an expansion of the combustion products at the stroke of the working stroke, and with further movement of the rotor, the exhaust window 11 opens and the exhaust gases are released. Then the cycle repeats.

From figure 2 it is seen that in order for hydrogen to fall into the zone adjacent to the rear apex of the rotor (φ _T ), its supply must be started at a point in time that coincides with the supply of a spark to the afterburning spark plug. If you start supplying hydrogen to the main air-fuel mixture earlier than the time of supplying the spark to the “T” after-burner, this will lead to an increased hydrogen consumption, and if later, to incomplete combustion of the main air-fuel mixture at the rear top of the rotor due to the lack of hydrogen addition.

By simulating the combustion process of a rotary piston engine, it was found that the supply of hydrogen to the zone adjacent to the rear top of the rotor is an effective way to increase the completeness of combustion of the air-fuel mixture in the RPD. Figure 5 shows the pattern of propagation of flame fronts with different amounts of hydrogen addition towards the rear apex of the rotor. In this case, the resulting fuel-air mixture with hydrogen additives is a mixture of stoichiometric composition (α = 1), and the amount of hydrogen addition is indicated as a percentage of the total mass of the supplied fuel. So, with the addition of 9% hydrogen, a noticeable decrease in incomplete burning near the rear peak is observed, and with the addition of hydrogen 13% or more, the flame front reaches the rear peak before the completion of the combustion process.

The complete burn-out of the air-fuel mixture can be achieved not only on mixtures of stoichiometric composition, but also on lean mixtures. Figure 6 shows the dependence of the amount of hydrogen addition on the coefficient of excess air at full engine load under various conditions of hydrogen supply. In the case of supplying hydrogen to the zone adjacent to the rear apex of the rotor, at each engine operation mode, it is possible to reduce the hydrogen consumption by 10% compared with the supply of hydrogen to the entire area of the RPD working chamber. The supply of hydrogen at the end of the intake stroke allows, while maintaining a positive effect, to reduce the consumption of hydrogen, which is important due to the difficulty of generating and storing large amounts of hydrogen on board mobile vehicles.

Due to the complete combustion of the air-fuel mixture in the RPD, the content of unburned hydrocarbons in the exhaust gases sharply decreases. In support of the foregoing, Fig. 7 shows a graph of the proportion of unfinished fuel versus engine load without adding hydrogen (α = 1). From Fig.7 it is seen that the addition of hydrogen several times reduces emissions of unburned hydrocarbons in the entire range of the load mode of the engine. So, at maximum load, the proportion of unburned fuel in the RPD combustion chamber is reduced by 14%, which leads to a corresponding increase in engine power and a decrease in the specific consumption of main fuel.

The proposed method for supplying hydrogen avoids premature ignition of hydrogen in the intake manifold, since hydrogen does not come into contact with the hot elements of the combustion chamber and the residual combustion products contained in it at the initial moment of the intake process.

The achieved result is to increase the completeness of combustion of the fuel-air mixture in the RPM with a lower consumption of hydrogen and, accordingly, to reduce the specific consumption of the main hydrocarbon fuel and the emission of toxic substances with exhaust gases.

Claims (1)

The method of operation of a rotary piston internal combustion engine with an epitrochoid working chamber and a trihedral rotor by supplying to the working chamber a fresh air-fuel mixture and hydrogen with a given coefficient of excess air, characterized in that the hydrogen is supplied to the zone adjacent to the rear apex of the rotor at a time coinciding with the supply of a spark to the afterburning spark plug.

Images