DE3047939A1 - Six-stroke IC engine cycle - has water or steam injected after second compression stroke, with closed exhaust valve and enlarged cylinder volume - Google Patents

Abstract

The i.c. engine operating cycle includes the introduction of heated and pressurised water or water vapour into the combustion chamber, which is superheated by heat generated in the combustion. It operates a six-stroke cycle consisting of inlet of fuel-air mixture, compression and ignition, a first working stroke (expansion), second compression stroke whilst the exhaust valve is closed, water or vapour injected and combustion chamber volume increased, second working stroke and finally exhaust of combustion products and expanded steam. A water or steam injector is arranged in the cylinder and a further injector may be arranged in the chamber. A similar process is possible for a rotary piston engine.

Description

The invention relates to a method for operating an internal combustion engine, with the addition of preheated or pretensioned material introduced into the thermal cycle under excess pressure Water or steam, the overheating of which takes place by utilizing the heat generated during the combustion process, as well as an internal combustion engine for performing this method.

The measures for internal combustion engines, the combustion air, the fuel or the fuel-air mixture non-combustible substances, in particular water or steam, have the main purpose of increasing the efficiency of the known internal combustion engines to improve, but also that contained in the combustion air

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to reduce harmful substances and counteract the tendency of the machine to knock. The most common and most important aim of the known measures, however, is to improve the energy balance by increasing the efficiency. Because with internal combustion engines in the conventional design go - regardless of whether they work according to the four-stroke or the two-stroke process. - About 70 % of the energy supplied with the fuel is lost in the form of hot exhaust gases and unused due to the cooling.

Numerous solutions have already been proposed to make the high temperatures generated during the combustion process, e.g. maximum combustion temperatures of 1500 to 2500 ⁰ C, exhaust gas temperatures between 500 and 1250 ⁰ C, depending on the working principle for the conversion of thermal energy into mechanical energy, by supplying water or steam in the combustion chamber of the machine to draw on and utilize the steam generated by heating to generate additional work. It is known to inject a predetermined amount of water into the cylinder of a piston engine at a certain point in the working cycle of the machine, for example in the initial phase of the compression stroke following bottom dead center (DE-PS 27 27 979), or, as in the DE-OS 19 58 732 and 26 29 783 described performing the injection together or at the same time with the fuel, the supply either taking place in the intake line of the fuel-air mixture or by prior mixing with the fuel, or by direct injection in the combustion chamber at the same time as or shortly after the fuel is injected. According to other proposals, the addition of water or DQmpf is related to the ignition point and the injection either shortly before ignition, at the same time as ignition, i.e. shortly before reaching top dead center (DE-OS 24 29 579) or shortly after ignition carried out or at the time of the highest combustion pressure and the highest temperature in order not to affect the combustion process (DE-OS 25 12 859, DE-AS 25 50 722).

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It has also been proposed (DE-PS 877 683), the addition of the water just before the end of the working stroke (expansion stroke), or during the discharge process, 'as in the DE-OS 28 26 834 described.

These engine designs include a water reservoir and facilities for preheating the water to be supplied, such as a heat exchanger that is attached to the exhaust manifold and the water or the supplied water mist is heated and converted into dry superheated steam. But it is also known to be preheated Subsequently feed water to a high pressure evaporator and there, utilizing the hot exhaust gases, to an over the steam pressure lying at the maximum combustion pressure, before the steam generated in this way in the saturated steam range enters the combustion chamber is fed (DE-OS 27 IJ 831).

All engines just described have in common that the individual Phases of the work cycles run basically unchanged, for example by the four strokes of a four-stroke engine in the usual Successive manner and only additionally, at the respectively defined point in time, water is injected or steam is supplied is to achieve a greater specific heat content of the combustion gas-steam mixture and to increase the power converted into mechanical energy. In contrast to this, the DE-OS 29 05 899 a combined combustion / steam engine known, in which there is a constant alternation of combustion and evaporation in the cylinder. As soon as the cylinder head, cylinder wall and If the piston crown has been heated sufficiently by the combustion processes of the fuel mixture, water is replaced in the compressed air injected by fuel mixture, and the engine now runs using the stored heat as a steam engine, and until a certain temperature of the previously listed Component is not reached. There is thus a constant change between, controlled by thermocouples, in an irregular sequence Combustion and steam operation take place.

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Another method for increasing the efficiency, which is described in DE-OS 2k 02 826, works according to a six-stroke process: Here the first four strokes run in the usual way according to the four-stroke process, with the hot combustion gases being expelled in the fourth stroke. This is followed by an additional work cycle with the injection of hot and pressurized water, whereby the steam that is now formed absorbs further heat from the combustion chamber and is overheated and thus does work. In the subsequent sixth stroke, the expanded steam is expelled, and then the six-stroke cycle begins again.

This working principle enables an improved utilization of the heat previously dissipated by the cooling water by part of the Combustion heat stored in the combustion chamber, the cylinder wall and in the piston can be used for the additional steam cycle is made and contributes to increasing the output. This method has the advantage that during a six-stroke cycle two work cycles run off. The disadvantage of this mode of operation, however, is that this motor during the first four strokes works in the same way as conventional piston engines, so the hot combustion gases are emitted as before, without the thermal energy contained therein being used.

The invention is based on the object of improving this method, with the aim of using the heat content of the combustion gases for the direct generation of mechanical energy close. According to the invention, this object has been achieved by the method specified in claim 1. At a The internal combustion engine operating according to the proposed method is a large part of the fuel mixture combustion generated heat made usable in the subsequent steam cycle after the combustion gases have been compressed again and the water vapor is injected. Another significant advantage of the invention is that the exhaust bang that occurs with conventional

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Motors at the moment of opening the exhaust valves or the exhaust ports arises, disappears, but the exhaust gases only become much more relaxed after the subsequent steam work cycle are emitted and no afterburning takes place. The exhaust noise is therefore significantly reduced, and so is the effort for the exhaust system can be significantly reduced. At the same time, the proportion of harmful substances emitted by the engine is also increased in the known manner by adding water vapor decreased.

The invention can be used in reciprocating piston engines and in rotary piston engines can be used in the same way and is illustrated below with reference to the drawings using examples of one and the other Engine design explained. Show it:

Pign. IA to IP the individual phases of a six-step process working reciprocating engine,

Figs. 2A to 2F show the individual phases of a six-stroke process working rotary piston engine.

The one in FIGS. IA to IP in the individual steps of a work cycle The illustrated cylinder of a reciprocating piston engine differs from the usual structure of the cylinders of four-stroke engines in the essential only in that between the inlet valve E and the outlet valve A a third valve, here referred to as a steam cycle valve D, is arranged and behind the valve plate of the steam cycle valve D, so above the same, an additional Compression chamber K is located. The steam cycle valve D and the Compression chambers K are arranged in the center of the cylinder head in the drawing, but they can also be located elsewhere Place to be provided. The spark plug, the injection nozzle with pump and other details are not in the drawing shown. The steam cycle valve D is controlled in a known manner Way, roughly through the camshaft.

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ORIGINAL INSPECTED

It should be noted that in the drawing only a single Cylinder is shown, however it is for what is described below Method for operating a valve-controlled reciprocating piston engine regardless of whether it is a single-cylinder engine or is a multi-cylinder M ~ -tcr; the working methods of each The cylinders are identical to one another and are controlled in the usual way with a corresponding phase shift. For The phase shift must be taken into account that the crankshaft, since the machine works according to the six-stroke process, in one work cycle makes three revolutions.

The operation of the cylinder according to the Pign. IA to IP is that the following:

Fig. IA shows the cycle "suction", the inlet valve E is for The supply of the fuel-air mixture is open, valves D and A are closed.

Fig. IB shows the "Compression" cycle, the fuel-air mixture is compressed, all valves are closed.

Fig. IC shows the first stroke "work" which is fuel ignited, all valves are closed.

Fig. ID shows the taxt "recompress" which are fuel gases compressed, the inlet valve E and the outlet valve A are closed, the steam cycle valve D is open, whereby the volume the combustion chamber is enlarged by that of the compression chamber K.

Fig. IE shows the second. "Work" cycle, preheated water or biased steam is injected and expanded, the Valve position is unchanged.

Fig. 15 'shows the "exhaust" cycle, the combustion gases and the

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Relaxed steam is expelled, the inlet valve E and the steam cycle valve D are closed, the outlet valve A is open.

The supply of water or steam through a nozzle or several nozzles takes place under a pressure which is higher than the compression pressure in the cylinder at the time of injection. This injection time is towards the end of the recompression cycle or at the beginning of the second work cycle selected so that the most effective relaxation of the now under the influence of the recorded Heat of superheated steam is achieved.

The representations in FIGS. 2A to 2F show in the corresponding Phases the mode of operation of a rotary piston engine operated in the six-stroke process, in which the rotary piston Is elliptically shaped and revolves in a trochoid-shaped combustion chamber. The connection between the rotary piston and As the figures show, the crankshaft takes place via an eccentric Pin in such a way that the crankshaft rotates in the opposite direction to that of the rotary piston. The piston forms on its piston sides A and B with the housing two periodically volume-variable working chambers, which thus convert offset a crankshaft angle of 180 °, so that the characteristics of a two-cylinder reciprocating engine are achieved.

The individual measures are shown in the following table:

Piston side A piston side B

Figure 2A - Suction Recompression

Fig. 2B ■ Compaction work (2nd cycle)

Fig. 2C Working (1st stroke) ejecting

Fig. 2D recompression suction

Fig. 2E work (2nd cycle) compression

Fig. 2F Ejection work (1st cycle)

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ORIGINAL INSPECTED

The inlet valve E ¹ and the outlet valve A 'as well as the steam cycle valve D ^{1 are} effective here in succession for each piston side. So the inlet valve E ^f opens for the duration of the work cycle "suction" of the piston side A according to Pig. 2A and opens again after a piston rotation of 18o for the intake day of the piston side B according to FIG A according to Fig. 2F. The steam cycle valve D 'opens during the recompression and the subsequent second working cycle, that is, for the piston side A in the piston position according to FIGS. 2D and 2E and for the piston side B in the piston position according to FIGS. ? A and 2B.

The spark plug, the injection nozzle with the associated pump and others structural details are not shown in this drawing either, since they are essential for the understanding of the six-stroke process described are dispensable.

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Claims (6)

Claims 1. J method for operating an internal combustion engine, with an addition of preheated or pretensioned water or steam introduced into the thermal cycle under excess pressure, which is overheated by utilizing the heat generated during the combustion process, characterized, that the internal combustion engine is operated in a six-stroke process, in which the following strokes run through will: 1.) Sucking in the fuel-air mixture 2.) Compression and ignition of the fuel-air mixture. 3.) Working (1st bar) 4.) Recompression of the combustion gases (with the outlet valve closed) with injection of water or steam, with a simultaneous enlargement of the combustion chamber 5.) Working (2nd bar) 6.) Ejection of the combustion gases and the expanded steam. 2. Internal combustion engine with a water / steam injection pump for performing the method according to claim 1, characterized ORIGINAL INSPECTED gekennzeichriet that the valve control takes place at sea in the sequence suction-compression-work-recompression-work-ejection and that an additional compression chamber (K) is arranged, which is in connection with the combustion chamber and increases its volume, as long as for the duration of the is WiederverdichtungstaK-th (4th)) and the second operating clock (5 x)) ^e i ⁿ between the combustion chamber and the compression chamber (K) befindliches clock steam valve (D) is opened. 3. Internal combustion engine according to claim 2, characterized in that the steam cycle valve (D) and the injection nozzle of the common control of the inlet valve (E, E ') and the outlet valve (A; A ¹ ) are controlled in synchronism. K. Internal combustion engine according to claims 2 and ~ $, characterized in that the preheated water or the pretensioned steam is injected simultaneously into the compression chamber (K) and into the combustion chamber by means of several injection nozzles.