DE2445147A1 - METHOD AND DEVICE FOR REDUCING POLLUTION IN THE EXHAUST GAS FROM HYDROCARBON COMBUSTION ENGINES - Google Patents

Description

9453-74

US note No. 399 498
from 09/21/1973
US note No. 449 391
from March 8, 1974

Cornell Research. Foundation 18 East Avenue
Ithaoa, New York

Method and device for reducing impurities in the exhaust gas of hydrocarbon internal combustion engines

The invention "relates to a method and an apparatus for Reduction of impurities, in particular nitrogen oxides, from the low-oxygen combustion products of an internal combustion engine with hydrocarbon fuel, the exhaust gas or the product of combustion normally being an undesirably high level Would contain excess oxides of nitrogen.

Numerous attempts have been made in recent years to provide efficient and relatively inexpensive exhaust gas cleaning devices to develop that when used with exhaust gases from a combustion of hydrocarbon fuel for a ensure the least possible environmental pollution. Motor vehicle pollution has been the subject of extensive Legislation, and the automotive industry is now trying to comply with the statutory provisions through appropriate bodies to meet the requirements of motor vehicles and finally to achieve the benchmarks for pollution control.

The background to this kind of pollution is as follows known. When an internal combustion engine operates on lean fuel, the concentrations of combustible hydrocarbon and carbon monoxide impurities in the exhaust gas are relatively low. When operating with a rich mixture

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the concentrations of these impurities are relatively high. On the other hand, the toxic oxides of nitrogen are in a maximum proportion present when the internal combustion engine is operating close to the correct fuel-air ratio will. If the machine is operated with either a rich mixture or a lean mixture, these are toxic Greatly reduced nitrogen oxides. An explanation of these pollution control problems is given in the How Clean a Car, "by John B. Jeywood, Technology Review, Volume 73, Number 8, June 1971," Alumni Association of the Massachusetts Institute of Technology.

In known solutions to the problem of undesirable impurities it was not possible to find a satisfactory solution to the system problem when operating with a lean mixture because the running properties of the machine are impaired if the machine starts and runs at all under these conditions. On the other hand, you have a lot to do with the company of internal combustion engines are concerned with a rich mixture in order to minimize these problems. For example the problem of the toxic oxides of nitrogen can be reduced to a minimum by using a fat Selects mixture that is close to 1.2 to 1.3 times the stoichiometric fuel-air ratio. Through this result in excessive concentrations of hydrocarbon and carbon monoxide impurities in the exhaust gas, which in turn can be removed from the exhaust gas by various devices, either as thermal reactors or as catalytic reactors can be used for this purpose. These processes lead to lower concentrations of impurities in the exhaust gas of automobiles and similar, .machine-driven devices, but this at the expense of fuel economy goes · Over time, professionals have for environmental protection and state legislative and control bodies even lower pollution levels in Exhaust systems prescribed ^ so that there is a need for even better exhaust gas cleaning devices

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Hydrocarbons and the carbon monoxides and NO are essentially eliminated from the exhaust gases of the engines. In particular the toxic oxides of nitrogen must be reduced considerably below the level of 1970 by 1977 (reduction of about 90 #).

The main difficulty now is finding a practical facility to reduce the inherent oxides of nitrogen that are present in the high-temperature gas atmosphere in the Working cylinders of the internal combustion engine are formed. from Research has proposed the use of catalytic reactors to solve this problem to the exhaust gas of an internal combustion engine post-treatment. Catalysis reduction reactors are used to reduce the oxides of nitrogen, and then the hydrocarbons and carbon monoxides are reduced by either a thermal reactor or a catalytic oxidation reactor. These procedures are in the following publications described:

¹ Search, by General Motors Research Laboratories, Volume 8, No. 4, July / August 1973

2. Article entitled "Exhaust System Passing Toughest Federal Tests, "Machine Design, Nov. 2, 1972, pp. 34-38

3. Article entitled "Calculation of Equilibrium Composition of Automotive Exhaust Gases" by Remo del Grosso, Ind. Eng. Chem. Process Des. Develop. " Volume 12, No. 3, 1973 »Pages to 394

From these publications, which are representative of the state of the art in the use of catalytic reactors, results that the catalytic reactor, which is used to control NO, from the continuous operation of the internal combustion engine at a fuel-air ratio that is continuously richer than the stoichiometric ratio, so that this Mixture is low in oxygen, as a result of which in turn an excess of CO and Hg is present in the exhaust gas, which is in the catalytic reactor must be processed. Furthermore, a is proportionate

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low NO content present, which must be further reduced by passing the exhaust gas into a chamber with a catalyst, usually made of metal of the group in which platinum is contained, or of basic metal, with for optimal interaction between the surface of the catalytic converter and the exhaust gas must be taken care of. This poses a significant number of mechanical and chemical problems when it comes to the reliability of this system. As can be seen from the articles mentioned, the catalyst serves to accelerate the chemical reactions in which the oxides of nitrogen are reduced to Np, etc. If the engine is not run with a mixture with a rich fuel-air ratio, the NO- Catalyst ineffective because the exhaust gas mixture is no longer reducing. It was also found that the types of fuel available here contain poisons which impair the various types of catalytic reactors known to date. Therefore, a standard gasoline was defined by government agencies in 1975 with regard to both lead and phosphorus content. Otherwise the catalytic reactor, as it is known heretofore, cannot provide a practical and reliable alternative solution to the problem of how the impurities in the exhaust gases of the internal combustion engine can be reduced to levels which are prescribed by government law. Furthermore, the catalytic reactor for reducing impurities in exhaust gases has a problem with the warm-up time. While the NO level in the exhaust gas is relatively low because the mixture used during warm-up is rich, the CO and hydrocarbon levels are at a very high level during this period, and the main control device for the hydrocarbons and CO ₁ Downstream of the engine and the NO reactor are shielded by the NO catalytic reactor (which has a large catalyst area) which initially cools the exhaust gases before they enter the primary control device (the second reactor or converter) before the content of hydrocarbons and CO can be controlled from the second reactor, the surfaces in the first reactor must therefore

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brought to the correct operating temperature, solutions this warm-up problem lead to complications in the system, which has a significant impact on the reliability of the catalytic reactor used in this troubleshooting.

It is therefore not certain that the catalytic reactor meets the reliability conditions Meets government regulations that require exhaust gas cleaning in automobiles during still complies with legal requirements for 5 years or 50,000 miles .

The invention is therefore based on the object of a new and improved method and a device for controlling the Report impurities contained in the exhaust gases from a combustion of hydrocarbon fuels. In particular the unwanted oxides of nitrogen, carbon monoxide and / or hydrocarbons are to be reduced are contained in the exhaust gas of an internal combustion engine.

According to one aspect of the invention, the reduction of the oxides of nitrogen in the exhaust gas of the internal combustion engine is thereby achieved accelerates that the exhaust gas is kept with a certain composition in a temperature range that this Reduction reaction is accelerated so that the reaction takes place in a short period of time, which depends on this temperature.

According to a further aspect, the reduction of the oxides of nitrogen is accelerated by the fact that unburned hydrocarbons burns off in a low-oxygen (fat) combustion product, which accelerates the reduction of NO, and is introduced at a sufficiently high temperature, the Acceleration to a practically acceptable, short response time leads. The

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associated response times for. Example approximately between 100 and 10 milliseconds.

The oxides of nitrogen in the combustion products of the internal combustion engine are reduced by the fact that the gases be subjected to a certain temperature for a sufficient time to remove the oxides of nitrogen without the presence of a catalytic converter and at the same time to reduce the exhaust gas at a temperature and a composition keep that when exposed to air in a thermoreactor leads to a temperature of the exhaust gas in this reactor which leads to a rapid conversion of the carbon monoxide in carbon dioxide and the hydrocarbon combustion products in water and carbon dioxide for a period of time which is too short for an undesired regeneration of Nitrogen oxides is effected.

It is advantageous ,, that the oxides of nitrogen are reduced in the products of combustion of an internal combustion engine by a device ₉ because it mostly the temperature-time response characteristic utilizing the gases, no restrictions on the reliability, neither mechanical nor chemical nature is subjected, which when using hot catalyst surfaces or walls. When reducing the impurities, the oxides of nitrogen, the carbon monoxides and hydrocarbons in the combustion products of an internal combustion engine, it is also advantageous according to the invention that this reduction does not depend critically on the specification of the fuel in terms of low phosphorus and / or lead content, so that no fuels other than those commercially available today do not have to be used. Another advantage is that the internal combustion engine does not have to be operated at a specific fuel-air ratio.

In another aspect of the invention there is a method and a device dispensed to remove the nitrogen oxides

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by introducing unburned hydrocarbons into the combustion products in each working cylinder, after the piston has passed through top dead center, that is, during the expansion stroke. This will make the Reduced nitrogen oxides while the exhaust gases are still in the working cylinder.

Another aspect of the invention is that the nitrogen oxides are reduced by the fact that an element in the working cylinder of an internal combustion engine in the space is introduced above the piston in the path of the products of combustion during the expansion stroke passed through the products of combustion is heated and together with the hydrocarbons released from the walls of the working cylinder during the Expansion stroke is stripped, which creates time-temperature conditions through which the toxic oxides of nitrogen be reduced.

In the invention, a heretofore unexploited one is essentially Characteristic of gaseous combustion products used, which have a high content of nitrogen oxide in the presence an excess of hydrocarbons contained in a relatively low-oxygen mixture, so that the reaction equilibrium of the nitrogen oxides is reached more quickly. The invention can be carried out in various ways.

The combustion products of the working cylinder are in a pail directed into the exhaust system and to an NO reduction chamber delivered in which the gaseous products contain at least the hydrogen that is not burned in the cylinder because they were near the cool cylinder walls. The gaseous hydrocarbons are used for Accelerating the breakdown of the oxides of nitrogen to the equilibrium state. At the same time the gas mixture is through a heat source is heated, which raises the temperature of the gaseous products, thus the equilibrium of nitrogen oxides is reached faster. The temperature of the gaseous

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Combustion products is raised so that the nitrogen oxides can be reduced to an acceptable level in response time and volume, in a reasonable context with the internal combustion engine. For example, a period of 10 to 100 milliseconds is sufficient to measure the NO content reduce when the reaction temperature is in the range of about 2600 ° to 2200 ° Rankine and a pressure of 1 atmosphere prevails. The temperature of the exhaust gas is high enough for a rapid thermal reaction when air is added is achieved by turning the unwanted carbon monoxide into carbon dioxide and unwanted hydrocarbons into water and Carbon dioxide can be reduced for a period of time which is too short for oxides of nitrogen to be regenerated.

In another pail is the working chamber of the cylinder, the the unwanted oxides of nitrogen generated during the expansion stroke of the piston, which is due to the passage through the top Dead center follows, used as a reduction chamber in that a preselected amount of hydrocarbons in gaseous form available to the combustion products at a time when the temperature in the gaseous exhaust gas products is already at a suitable reduction temperature, the the volume and the duration of the expansion stroke in the working cylinder is coordinated. When the products of combustion are on the time at which the hydrocarbons are added are not low in oxygen, in this case generate the first Hydrocarbons initially have such a state as an intermediate stage in which the remaining hydrocarbon gases then reduce the nitrogen oxides in the manner mentioned.

In another case, the working chamber of the cylinder that generates the undesired nitrogen oxides is used as the reduction chamber used during the exhaust stroke of the piston by removing the unburned Hydrocarbons stripped from the walls of the cylinder during the exhaust stroke are used, and the low-oxygen exhaust gas mixture is heated up as a result,

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that it is passed over a hot, uncooled surface in the exhaust path in the compression volume of the working chamber. The hot surface is heated up by the combustion products.

According to a special embodiment of the invention, the combustion device operated with hydrocarbon fuel is used initially operated so that a fuel-lean combustion product with. Nitrogen oxides and an excess of oxygen is produced. As a preparatory step, a certain Amount of unburned hydrocarbons supplied to at least part of the fuel-lean combustion product, the unburned hydrocarbons being sufficient to remove the excess oxygen and thereby the resulting combustion product 'to make oxygen deficient.

The invention can be specifically summarized as follows: The gaseous hydrogens in the combustion products v / ground at a sufficiently high temperature in a corresponding manner selected closed volume brought together, so that the reduction of nitrogen oxides accelerated to such an extent that the NO is reduced to an acceptable level in a preselected response time that is related to the volume stands. The reaction time, the volume and the temperature are matched to the parameters of the internal combustion engine.

Embodiments of the invention will now be based on the enclosed Drawings described. Show it:

1 shows a simplified, schematic representation of a cylinder of a spark ignited internal combustion engine to explain the invention;

Fig. 2 is a simplified graph showing the composition of the exhaust gases of the working cylinder of Figure 1 shows at different fuel-air ratios;

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FIG. 3 shows a block diagram of the components of the device according to the invention in a simple form as shown a source of combustion products of hydrocarbon off burning is connected openly;

Figure 4 is a more detailed block diagram showing the reducer for the control of nitrogen oxides in an internal combustion engine, followed by an oxidation device, shows the remaining hydrocarbons and remove carbon monoxide;

Fig. 5 a to 5 k alternative methods in the context of Invention in which the reduction of the toxic NO is carried out in the working chamber, wherein; Fig. 5a shows how liquid hydrocarbons are injected into the working chamber by conventional fuel injection are injected after the start of and during the expansion stroke of the working cylinder;

Fig. 5 b shows another device in which hydrocarbons in the working cylinder after initial explosion can be introduced during the expansion stroke that provided with openings Cavities are used in the top of the piston;

Fig. 5c shows an alternative method in which small cavities with communication openings in the upper Part of the working cylinder are arranged in the compression chamber in such a way that the distribution of unburned, gaseous hydrocarbons after the initial explosion during the expansion stroke will;

FIG. 5 d shows a further, alternative method similar to FIG. 5 c, in which a cavity with openings at the top of the cylinder is arranged in such a way as to reduce the distribution of unburned, gaseous To ease hydrocarbons after the initial explosion during the expansion stroke;

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Fig. 5e shows an alternative method in which a cavity for trapping unburned hydrocarbons is connected to the working chamber by a venturi tube;

FIG. 5f shows an arrangement similar to FIG. 5e, with the exception that hydrocarbons enter the cavity. Fuel fuel is added to deliver additional hydrocarbons to the gases that make up the cavity to leave the cylinder; 5g shows an arrangement that is similar in function as FIGS. 5e and 5f show, with excess fuel also being supplied; Fig. 5h shows an arrangement in which the working chamber is used as a reduction chamber for NO, as is the case with the arrangements according to FIGS. 5 a to 5 g, but with the reduction during of the exhaust stroke instead of during the expansion stroke is achieved in that the unburned hydrocarbons, which are stripped from the cylinder walls during the exhaust stroke, used and heated, Uncooled surfaces heated by the combustion gases in the path of the combustion gases to be used; and

6 to 12 different versions of spark plugs which are designed according to the invention.

As mentioned earlier, the generation of toxic oxides of nitrogen is in the products of combustion of hydrocarbons off burning the most difficult problem with the control the pollution from such an incineration. Figure shows that combustion is either with rich fuel or must be carried out on lean fuel in order to minimize the production of NO during combustion. Practical criteria seem to require that such internal combustion engines, such as internal combustion engines ignited by ignition sparks, work on rich fuel to increase the production of NO

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Reduce levels that meet the increasingly stringent requirements to suffice. In fact, the exhaust gas still has to undergo a further NO reduction after the hydrocarbon and carbon monoxide reduction, thereby giving rise to the above undesirable consequences. In this In context, the invention teaches that the reduction of NO in the exhaust gas to acceptable levels in the combustion products in a reasonable amount of time requires that the exhaust gas be subjected to a temperature higher than the temperature, those in the exhaust system outside the working chamber of the cylinder would occur in an internal combustion engine, and that it is also necessary (as is known per se) that the exhaust gas must be lean in oxygen and contain a substantial amount of hydrocarbons in gaseous form, wherein no catalyst has to be present which is known to be incompatible with such high temperatures.

The working cylinder of an internal combustion engine with spark ignition is shown in FIG. The engine operates on a rich fuel mixture, and its piston is close to bottom dead center (BDC) and begins its exhaust stroke (the exhaust valve is just opening). The gases expanded by the energy have a temperature of around 2600 ° Rankine. When the exhaust valve opens, the temperature of the gas in the cylinder drops sharply to about 2000 ° Rankine and moves into the exhaust system under a pressure of about 1 atmosphere into the chamber 15. Theoretically, the hydrocarbon in the working cylinder was in Gaseous form was present, burned during combustion. However, some of the hydrocarbon is cooled by the cooled walls during combustion and is not available for combustion during the expansion stroke. This hydrocarbon is stripped from the walls during the exhaust stroke and mixes with the hot exhaust gases and moves with the expanded gases into the exhaust system and chamber 15 along with HpO, CO ₂ and other combustion products including the undesirable major contaminants NO and

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CO. This hydrocarbon is shown as a dashed line in Figure 2 to indicate that it is in a different state than the combustion product. From a practical point of view, for example Y / economic efficiency (kilometers mileage per unit of fuel), and technical problems such as oil dilution and carbon formation it is not advisable to use such a rich mixture that the NO in the exhaust system is reduced to such an extent that the increasingly strict guidelines are met. Therefore, the chamber 15 can serve as a NO reduction chamber. This is followed by a second chamber (not shown) to reduce residual hydrocarbons and CO. According to the state of the art, this would be the chamber 15 has a catalytic converter which has many catalytic surfaces in order to accelerate the reduction of RO to N ", etc. It is known that the presence of gaseous hydrocarbons in chamber 15 is critical for catalytic reactors, to accelerate the NO reduction. However, it is also known that these hydrocarbons are sufficient without a catalyst, when the temperature of the gases in the chamber 15 is at a temperature is kept close to the temperature present in the working cylinder just before the exhaust valve is opened is. A heater is shown in FIG. 1 to illustrate this principle. This heater would (according to the teaching of the invention) the gases in the chamber 15 to a temperature range of Heat up from 2200 ° to 2600 ° Rankine, this temperature range taking into account the corresponding reaction time and the volume of the chamber 15 is determined. In practice, however, heating is not necessary if there is a loss of heat (and the associated temperature drop) in the passage between the working cylinder and the chamber 15 is prevented. Alternatively, the working cylinder itself can be used as a NO reduction chamber after the initial explosion and during the last part of the expansion stroke before the exhaust valve is opened, serve when gaseous hydrocarbons enter each of the working cylinders during the final stages of the expansion stroke be injected so that the NO contained therein is reduced. This solution is discussed below in connection with the

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Figures 5 a to 5 k described. It should be noted that the hydrocarbons which, as mentioned above, are present in the cylinder walls and the end face of the piston in a low temperature state are not available in the cylinder for the purpose of NO reduction during the expansion stroke. According to Figure 5, the hydrocarbons are, however, stripped away from the cylinder walls during the exhaust stroke and used at non-refrigerated, heated surfaces in Mege of exhaust gases for the reduction of NO in the working chamber during the exhaust stroke h ·

Heretofore it has been believed that a catalytic converter is required along with a reducing mixture of exhaust gases to reduce NO in a practically acceptable time. It has been recognized that the fuel to air ratio must be a richer than stoichiometric mixture to ensure that the mixture is oxygen deficient. It was generally believed that CO and Hg were required as reactants when a catalytic reactor was employed. However, it was not recognized that there is a clear alternative in that the NO reduction can be accelerated by adding hydrocarbons and increasing the temperature of the gases. For example, the temperature of the exhaust gas could be raised to the previously unexamined range of 2200 ° to 2600 ° Rankine during a relatively short period of time (100 to 10 milliseconds, respectively) and held there. This removes the NO, and at the same time one does not have to fall back on catalyst materials with all their disadvantages of mechanical and chemical stability in long-term operation. However, this long-term operation is essential for the successful use of such a system for exhaust gas purification. Considerable benefit is derived from this because the use of catalytic reactors brings with it many problems in connection with reliability and economy or cost. In essence, the invention is thus based on the fact that the return of NO to its equilibrium state of N ₂ etc. is thereby accelerated can ^ that the gases containing the NO with a suitable composition on a certain

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Temperature range are maintained. This process can be done in a short period of time available for processing the exhaust gases and determined by selecting the volume of the reduction chamber taking into account the amount of impurities will take place. The contaminants are those that come from a source of exhaust gas during combustion are emitted by hydrocarbons, for example from a conventional internal combustion engine.

This is shown in Figure 3, the exhaust gas being from an exhaust gas source unwanted nitrogen oxides, an excess of hydrocarbon contains compounds and CO. The excess of CO indicates that there is a low oxygen content in the subsequent reduction chamber 2 is present. In the presence of excess hydrocarbons, some of which are in the Reduction chamber 2 can be used when the temperature in the chamber is in the range of about 2200 ° to 2600 ° during Rankine is maintained for a suitably selected short period of time, the NO in the exhaust gas is reduced to an acceptable level. If the exhaust gas from the exhaust gas source is not in the desired temperature range, a device in the NO reduction chamber 2 can be provided to supply the thermal energy to deliver the exhaust gas that is necessary to reach this temperature range.

The pressure and the temperature of the exhaust gas in the reduction chamber 2 determines the average exhaust gas density in this chamber .. The Amount of exhaust gas per unit of time from exhaust gas source 1 (source of air pollution) divided by the mean density in the reduction chamber 2 multiplied by the selected reaction time determines the appropriate volume of the reduction chamber 2,

The temperature range is given above only approximately because several interrelated variables are involved are. The essential thing in the invention is the rapid return of the nitrogen oxides to the state of equilibrium, when the exhaust products have an excess of hydrocarbons

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and are low in oxygen and exposed to an elevated temperature in excess of the temperature heretofore recognized as useful by those of ordinary skill in the art. It is believed, however, that if there are enough hydrocarbons to produce a sufficient number of molecular collisions (between NO and hydrocarbon compounds), and if there is enough thermal energy to produce the threshold energy, the reduction reaction will proceed at such a rapid rate that as it has not been recognized before. It has been shown that with spark ignited internal combustion engines, the exhaust gas is approximately under the pressure of one atmosphere, and using a corresponding volume for the reduction chamber 2, a range of about 2200 ° to 2600 ° Rankine can be used and to a corresponding range of Response time (100 to 10 milliseconds). This applies to the application in automobiles.

Changes in the conditions of use even with spark-ignited Internal combustion engines can have other temperatures (which of course are higher than the temperatures when in use of a catalyst lie with the same volume) and therefore require or allow other time and pressure conditions than they are given here.

Although the NO reduction in the reduction chamber 2 (Figure 3) depends on an excess of hydrocarbons, after the Reduction of NO according to the invention many of these products remain discharged exhaust gas approximately in the same state as the exhaust gas that comes from the NO reduction catalytic reactor of known design except that the exhaust gas is at a much higher temperature. According to the teaching of the invention, this fact has a beneficial effect on the hydrocarbon and CO reduction chamber arrangement, which was not achievable with known methods. The reason is that one more or less conventional oxidation chamber with an addition of excess

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Air with a higher efficiency in the exhaust gas temperature ranges can work, in which the gas is released into the chamber 3 of FIG. While in the present example the exhaust gas entering chamber 3 from chamber 2 has a temperature of more than 2000 Rankine, and therefore the hydrocarbon and CO reduction can take place both in a reasonable volume and in a reasonable amount of time Compatible with the design of contemporary automobiles, it should be noted that this temperature never. Exceed 3300 ° Rankine should, because at this temperature there is a risk of nitrogen oxides being formed in the reduction chamber 2 have been effectively eliminated by the method of the invention.

While FIG. 3 illustrates the basic idea of the invention, when the invention is applied to a special machine, FIG In practice, further technical measures are required in order to meet practical conditions. Application of the invention to Internal combustion engines require that the exhaust gas flowing from the source 1 to the NO reduction chamber 2 in a temperature range from about 2200 ° to 2600 ° Rankine, an excess of hydrocarbons and at the same time a low content of Contains oxygen. An internal combustion engine that operated at a higher than stoichiometric mixing ratio can of course provide the excess hydrocarbons and the low oxygen content. In practice however, the engine may not be able to discharge the exhaust gas in the desired temperature range. In this In this case, it may be desirable for the reaction chamber 2 to have a pre-combustion stage includes, in which the temperature of the exhaust gas is raised to the desired temperature range.

In FIG. 4, the NO reduction chamber 21 is preceded by a combustion stage with a combustion chamber 22 in which the fuel is burned after a suitable amount of air has been mixed in (after passing through a carburetor 26). The air is supplied by an air pump. This measure increases the temperature of the exhaust gases

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elevated. A perforated plate 35 is shown as a gas catcher. During the start-up process, it is important that a spark source 38 in the combustion chamber 22 is in operation to control the flame ignite.

The amount of fuel consumed by the carburetor 26 changes depending on the amount that is required to raise the temperature of the unmodified exhaust gas from the internal combustion engine as it enters the NO reduction chamber 21 and the amount of fuel that is required maintain the emaciated oxygen mixture, and also depending on the presence of unburned hydrocarbons in the exhaust gas, which is subjected in the reduction chamber 21 of a NO reduction.

It should be noted that the volume of the reduction chamber 21 divided by the exhaust gas mass emitted per unit of time is determined by the mean density of the exhaust gas and multiplied by the selected reaction time, which is determined by the temperature and the level of NO reduction desired. The shape of the reduction chamber 21 can be varied within wide limits can be modified to take into account structural requirements of the exhaust gas source in a hydrocarbon combustion engine. Certain general restrictions must be observed, with (1) the warm-up time, (2) the external heat loss and (3) the uniformity of the flow and the generated back pressure, etc.

The approximate temperature range (FIG. 4) for the gases in chamber 21 is suitable for internal combustion engines. With others Applications of the invention may require other temperature ranges depending on the criteria can be used to select the volume of the reduction chamber.

After the NO reduction, the exhaust gas emerges from chamber 21 (FIG. 4) and can then contain an excess of liquid hydrogen. It also certainly contains undesirable CO and

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very likely to exceed the strict pollution standards. If this is the case, the polluting components can either pass through a catalytic reactor or a thermal reactor can be removed in a manner known per se.

The temperature of the exhaust gas from chamber 21 (FIG. 4) can be in the vicinity of the upper operating temperature limit for catalytic reactors (i.e. above 2000 ° Rankine). Such a high temperature is logically suitable for a thermoreactor. Consequently, as shown in FIG. 4, the exhaust gas is discharged from the chamber 21 into a thermal reactor, which is shown as the hydrocarbon and CO reduction chamber 30 and mixes the hydrocarbons and the CO with air from the air pump 24, so that these impurities are oxidized in FIG ^ 0 and CO _{2 are} implemented. The design of the oxidation chamber 30 can be carried out according to known principles. The relatively high temperature of the exhaust gas from the NO reduction karamer 21, however, promotes the oxidation process when this exhaust gas is brought into contact with air. However, the temperature in the chamber 30 should not be able to rise to above 3300 ° Rankine in order to prevent NO formation. As the temperature of the exhaust gas increases in the presence of oxygen, the time required for the NO to reach its new, extraordinarily high state of equilibrium becomes shorter.

The temperature range indicated on chamber 21 in Figure 4 is intended to indicate the approximate range within which a particular operating temperature can be selected based on the best economics of the system. With this temperature selected, it may be desirable to maintain the temperature of the exhaust gas in chamber 21 for a wide range of different operating conditions by an automatic control device. If there is no deterioration in the components or the system, the speed of the internal combustion engine is an indicator for <the exhaust gas temperature ¹ . This relationship provides the means to control the burners so that the desired setpoint temperature in chamber 21 is present. A conventional flow divider

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(e.g. a valve 37) is mechanically attached to the tachometer 32 connected so that the flow from the air pump 24 to the chamber 22 can be adjusted in a suitable manner to the heat supplied by the combustion chamber 22 steer. If direct control of the temperature is required, the temperature can be measured in a manner known per se to divide the flow path via valve 37 or other flow control device. As alternative the temperature in the chamber 21 can be allowed to fluctuate within an acceptable range, if only because of the restrictions of the NO are not violated. The spark source 38 can be a be conventional spark plugs, with periodically recurring high-voltage pulses being applied to it in a manner known per se will.

As mentioned above, it is proposed according to the invention that each Working cylinder of the internal combustion engine as an NO reduction chamber during the part of the expansion stroke, then the primary ignition of the "combustible mixture" with the associated ones high temperatures and high pressures follows, and before opening the exhaust valve acts, leaving the gaseous hydrocarbons can be effectively injected into the working chamber so that the NO generated therein is reduced.

In Figure 5 a is a working cylinder similar as shown in Figure 1 with the gutted © _p that durcli a conventional fuel Einspritsvorriclilrung are taken 50 measures (hydrocarbon compounds) is injected under sufficient Druek by at the right time fuel, so that the Hydrocarbons can be dispersed in the working chamber in order to accelerate the NO reduction according to the teaching of the invention. It should be noted that the gases in the working chamber during the last part of the expansion stroke are at a temperature slightly above 2600 ° Rankine, so that a continuous reduction of NO is effected during the expansion stroke. The timing of the fuel injection is of course based on the conventional fuel injection

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Techniques controlled as they are currently used for fuel injection can be used by internal combustion engines (for example by pulse control of a metering valve 51). The. use the working chamber of the working cylinder to reduce NO, as proposed according to the invention, can take place in many different designs. All exemplary embodiments What is common, however, is that unburned, gaseous hydrocarbons are mixed with the gaseous products of combustion must be, the mixture (for a corresponding period of time) must be kept at a temperature that is above the temperature normally present in exhaust gases after opening the exhaust valve.

Another embodiment is shown in FIG. There the end face of the working piston is provided with apertured cavities 55 so that gaseous hydrocarbons are trapped during the intake stroke, held therein during the compression stroke and released during the high pressure sections of the expansion stroke. At this point in time they are available as unburned hydrocarbons, which are required for NO reduction at the high temperatures above or around 2600 ° Rankine during the last part of the expansion stroke, so that the exhaust gas from the working chamber is kept to a minimum during the exhaust stroke of NO, but contains an undesirable amount of hydrocarbons, which are now stripped from the cylinder wall in gaseous form. The exhaust gas also contains an undesirably high amount of CO. Within the scope of the invention in this pipe is gas either a per se known catalytic-oxidation reactor or an oxidizing thermal reactor may be used to reduce the amounts of hydrocarbons and CO in the exhaust gas to the strict guidelines, which are required by the regulations.

The amount of unburned hydrocarbons required to mix with the combustion products in the working cylinder at the elevated temperature is proportional

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small. In the exemplary embodiments according to FIGS. 5 a to 5 h, however, the possibility must be taken into account that the Hydrocarbon compounds, which are intended to serve this purpose, are burned before they serve the purpose of reducing the Oxides of nitrogen have met because these compounds exist as a flammable mixture rather than in a non-flammable form. the Design of the cavities 56 provided with openings in FIG. 5b with regard to position, volume, number, shape, etc. is illustrated by the Determines the need to trap hydrocarbons during the intake and compression strokes and relieve them with the To mix combustion products during the expansion stroke, so that the hydrocarbons are in unburned form:;. In good Mixing with the combustion products are available. The products of combustion that are in the initial step of the expansion stroke can help prevent the trapped hydrocarbons from burning They will mix with these hydrocarbons early. In particular, the products of combustion in enter the cavity 56 to the composition of the enclosed Change gas so that a non-flammable mixture arises. As a result, unburned hydrocarbon compounds are retained for distribution in the remaining combustion products. It is believed that some of the included Hydrocarbons are still burned. It is important, however, that there are enough unburned hydrocarbons in the final oxygen-depleted mixture of combustion products remains, in this atmosphere the NO should be reduced. One of the ways to safely meet these conditions is through optimal magnification the volume of the cavities and / or, alternatively, the optimal increase in the fuel-air ratio in the direction of on a rich fuel mixture, which is then fed to the working cylinder.

Fig. 5 shows another embodiment to get unburned hydrocarbons into the working cylinder after the explosion introduce at a time when the expansion stroke

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begins. Small cavities 56 are arranged in the top of the working cylinder in the compression space (above top dead center) in such a way as to facilitate the distribution of the unburned gaseous hydrocarbons for the purpose of accelerating the reduction of the NO which is present in high temperature and high pressure -Combustion atmosphere of the initial explosion is created. The location, volume and shape of the cavities 56 must be selected to facilitate as close a mixing as possible of the unburned hydrocarbons with the products of the hydrocarbon combustion with rich fuel, this combustion taking place during the initial explosion. In addition, however, some hydrocarbons must be kept in a non-combustible state as described above. It should be noted that the combustion at the beginning of the explosion must produce an oxygen-lean mixture.

Another embodiment for practicing the invention is shown in Pig. 5d shown. There will be a facility with a Cavity 58 into an opening in the top of the working cylinder used in a manner not dissimilar to attaching a spark plug (e.g., by threading). A plurality of openings 60 are provided through the end wall closing the cavity 58 and form an open connection between the cavity 58 and the working cylinder. During the compression stroke, there is a pressure difference, the fuel mixture including unburned gaseous hydrocarbons pushes through the openings 60 into the cavity 58. In other words, the high pressure state becomes at the upper part of the Cylinder in the compression chamber is also generated in the cavity 58. During the beginning of the combustion explosion, the products of combustion are also passed through the openings 60 into the cavity 58 pressed in, so that a large part of the unburned hydrocarbons contained in it in an unburned State is maintained because a non-combustible mixture is created. After the initial explosion is the Pressure of the gases in the cavity 58 is greater than the pressure in the Working cylinder because the volume in the working cylinder

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~ ²⁴ ~. 2AA5H7

increased to an increasing extent during the expansion stroke. Through this the gases enriched in burned hydrocarbons are transferred to the oxygen-depleted mixture in the working cylinder sprayed through the openings 60, so that the nitrogen oxides in the working cylinder after the initial Stages of the expansion stroke are reduced because both the temperature and the gas composition in the working chamber favor such a reduction »After the expansion stroke, the exhaust gas, which contains an excess of undesired carbon monoxides and containing hydrocarbons, are passed through a special reduction chamber, known per se Procedures are applied.

The use of a cavity to collect unburned hydrocarbons for NO reduction can be done in a number of ways, and in many cases the cavity can remain in open communication with the working chamber. FIG. 5e is such an exemplary embodiment. The cavity 61 shown there has a recessed section on the side remote from the working chamber, the entrance to the cavity having a reduced cross section in order to achieve a Venturi effect through the openings 62, as is still the case is described. During the intake stroke, the fuel mixture fills the. Cavity 61 as well as the working chamber. During the compression stroke, additional fuel mixture including hydrocarbons is introduced into the cavity 61. After the initial combustion in the expansion phase, however, increases the volume of the working chamber, and unburned _f gaseous hydrocarbons from the cavity 61 pass through the Venturiöffniingen 62 in burnt form, whereby the mixing of the unburned hydrocarbons is facilitated in the mixture with the combustion products, the then exit the chamber and come into close contact with the NO in the combustion products in the working chamber.

509813/0372

- ° "2U5H7

The optimal volume and shape of the cavity 61 is determined by the need for optimal mixing of the combustion products with the fuel mixture during discharge determined from the cavity 61 during the expansion stroke.

Figure 5f shows a similar embodiment to Fig. 5e with the exception that hydrocarbon fuel in liquid The mold is inserted into the recessed part of the cavity, facing away from the working chamber, the liquid hydrocarbon off burns off is comparatively little volatile, like it is the case, for example, with oil. A check valve 65 between the cavity and the fuel source can prevent that gases from the cylinder enter the liquid hydrocarbon fuel. The venturi shaped fuel port 66 is also designed differently than the previous one Embodiment. During the intake and compression strokes, the fuel mixture, including the hydrocarbons compressed in the cavity 64. During the initial explosion of combustion on the expansion stroke will be Combustion products pressed into cavity 64. During the last part of the expansion stroke, in which the As the volume of the working chamber is increased, the products of combustion are followed by the fuel mixture contained in the Lumen 64 is contained, discharged through the venturi, allowing liquid fuel from the rear of the cavity is injected into the gases so that they mix with the products of combustion in the working chamber to the therein to reduce NO.

In the embodiment of Figure 5g, the cavity 71 » in which the unburned hydrocarbon compounds are stored, with the working chamber through a double-acting Ball check valve 72, a mixing tube 73 and mixing ports 78 in connection, with additional fuel metering ports 74 are provided. The ball check valve 73 closes the pipe 75 in a first, lower position, which during the Suction stroke of the piston connects with the working chamber

509813/0372

manufactures, and closes in its second position during the compression, expansion and exhaust stroke of the piston Pipe 76, which establishes the connection to a supply of liquid hydrocarbon st off burn off «, during the intake stroke Due to a pressure difference, fuel moves through the fuel metering openings 74 from the fuel supply 79 the open tube 76, evaporates and flows into the mixing tube 73 and into the cavity 71. During the compression stroke, the Fuel mixture in the working chamber through the open pipe 75 into the mixing pipe 73 and also into the cavity 7 "! mixing with additional vaporized hydrocarbons. During the initial combustion phase of the expan- sion stroke, the combustion products pass through the pipe 75 into the mixing pipe 73 and also into the cavity 71 via a plurality of mixing openings. 78 ®in, dealing with the unburned Mix hydrocarbons so that a substantial amount is rendered non-flammable, thereby reducing the remainder Part of the expansion stroke the unburned, gaseous hydrocarbons return to the working chamber to deal with to mix the remaining combustion products to reduce the NO content they contain. The cross-sectional area of the Tube 76 is determined by the required amount of additional, vaporized hydrocarbons that are in the working chamber should be present during the expansion stroke after the explosion.

It has already been mentioned that hydrocarbons are present on the walls of the working cylinders during the expansion stroke. These hydrocarbon compounds are not available for combustion during the expansion stroke because they are close to the cooled cylinder walls. For the same reason, these hydrocarbons are not always available to supply the gaseous hydrocarbons © for the IfO reduction _P which according to & φτ ssi ^ n ^ lioliea, Ystrb ^ & mmiig weto ^ M des Exp ^ isionsMibesö _o MiA @ Teym® itB Wiwl & ü, according to the invention di @ KoiÜj3BMQMBer®to £ fe. _r & i © ¥ oa den Zjlfm & @ ^ fan && ii during the puff! iii.ßee stripped usrd © ^ in the ü ^ MitssyiiMer nacl ?.

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used when opening the exhaust valve and during the exhaust stroke when the temperature of the combustion products in the working cylinder is high enough. When the exhaust valve opens, there is a considerable drop in pressure and temperature the products of combustion that remain in the cylinder during the exhaust stroke. According to the invention, however, the temperature on the route taken by the products of combustion, can be increased by having one or more heated surfaces 80 in the The compression chamber of the cylinder is arranged next to the exhaust valve (Fig. 5h). The heated surfaces 80 may, for example, be made of stainless steel in the form of one or more Rings be formed, which are attached to the top of the cylinder wall in a manner known per se with pins. The surfaces 80 are heated up by the combustion process and are used to heat the combustion products during the exhaust stroke, when the hydrocarbons (which were previously on the sides of the cylinder) are present for NO reduction are.

Figures 1, 3 and 4 show one way of carrying out the invention, while FIGS. 5a to 5g show another way of carrying out the invention. Figure 5h shows another further execution option. It is to be emphasized that the two first-mentioned embodiments or all three embodiments can be applied simultaneously to special Use cases to bring about the reduction of NO.

The invention has a number of advantages and can be used in many different ways Embodiments are implemented to reduce the NO pollutants in the products of hydrocarbon combustion to reduce. It should be noted that when using the embodiment of Figure 4, that is, a separate source for Hydrocarbons, used to raise the temperature of the exhaust gas from the working cylinder, are also used to do this can be that with certainty a sufficient amount of excess hydrocarbons is available to the Accelerate reduction of NO. In this way, the

509813/0372

Main source of contaminants (the internal combustion engine) would work at any fuel-air ratio may be desirable according to other design criteria. In the embodiment of the invention, in which the working chamber is used to reduce NO, the engine must run at a greater than stoichiometric ratio. However, this is fully consistent with the preferred mixing ratios for spark ignited internal combustion engines, what was already recognized before the legal provisions were introduced that reduce the amount of contamination Require strict guidelines for NO, hydrocarbons and CO.

The second or additional source of hydrocarbon fuel when used to practice the invention need not be the same high grade fuel as the fuel deliver, which provides for the drive of the internal combustion engine. All embodiments of the invention can be proportionate by simple changes to existing machines can be implemented. The second source of hydrocarbon means if needed to practice the invention, not a great compromise in terms of economy, if one compares this arrangement with known arrangements for solving the same problem. The use of appropriate insulation in connection with the exhaust system, which follows the combustion chamber, the post-heating costs for the exhaust products, which are necessary to achieve the appropriate reaction times, reduce to a minimum. If the exhaust fumes a NO reduction stage, followed by a hydrocarbon and CO reduction stage, there is only a small need for further separators in the exhaust system. The invention can be used on both two-stroke and four-stroke machines. Obviously, the invention can also be applied to various Machine types, for example the reciprocating internal combustion engine, the rotary piston engine, turbines and Wankel engines, be applied. In the case of turbines, the NO reduction chamber would be outside the "working chamber" while in the

509813/0372

Wankel engine either inside or inside the NO reduction chamber can lie outside the combustion chambers.

The invention can also be applied to internal combustion engines with fuel injection, for example diesel engines. While the diesel engine at a slightly richer than the stoichiometric Fuel mixture must be driven, which leads to a certain increase in fuel consumption, is that Fuel injection device, which supplies the gaseous hydrocarbon compounds, already part of the engine. The fuel injector only has to be changed in its timing so that the second smaller injection of hydrocarbons takes place after the initial explosion during the expansion stroke.

The invention is also for controlling the products of the hydrocarbon off combustion in heating systems and electrical generators applicable. Indeed, the second heater for the NO reduction outside of the primary combustion chamber can be kept very small, as an extensive heat exchanger can be developed since space requirements for the incinerator do not play a primary role. When applied According to the invention, the high-performance system can be relocated closer to the sites or customers, so that savings can be made Transfer costs.

The invention is equally applicable to movable and stationary ones Carbon fuel burners applicable for domestic use.

Further embodiments of the invention are described below. In Figure 5i an arrangement is shown in which a conventional spark plug is modified to have a cavity 82 around the base of the spark plug, with one or more access openings 83 being provided. This will created an arrangement which corresponds functionally to the arrangement shown in Figure 5d and a screw-in unit

509813/0372

to form the cavity. The location of cavity 82 and opening 83 immediately adjacent to the spark plug is in fact advantageous, since this is where the hottest point in the working chamber during the expansion stroke is from where this Reason usually more NO is produced. The cavity 82 and the openings 83 are designed differently from conventional ones Spark plugs. The volume and shape of the cavity 82 and the number and size of the openings 83 must be carefully selected that fuel mixing during the intake and compression strokes is pushed into cavity 82 in an amount such that sufficient hydrocarbon is in the cavity stored in order to deal with the combustion products of the working chamber during the initial explosion during combustion- mixed to ground. A considerable amount of the hydrocarbons stored in this manner should be non-ignitable are made and are available to be sprayed into the working chamber during the remainder of the expansion stroke so that the hydrocarbons Mix with the remaining combustion products as unburned, gaseous hydrocarbons. That way then will the NO in the oxygen-depleted atmosphere is reduced in the corresponding reaction time and the corresponding volume.

The arrangement of Figure 5j operates similarly to the spark plug arrangement of Figure 5 i with the exception that an additional fuel supply 85 by a preloaded check valve 86 is connected to via a fuel supply pipe 86 to deliver hydrocarbons to cavity 88 during the intake stroke of the piston. This will increase the presence Ensured of enough hydrocarbon by allowing unburned hydrocarbon to mix with the oxygen-poor Combustion products delivered during the expansion stroke following the initial combustion explosion. The reduction of the NO can then take place in the oxygen-poor environment in the appropriate reaction time and the assigned volume occur. The non-return valve preloaded by a spring

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valve 86 is only open during the intake stroke.

Figure 5k shows an embodiment similar to Figure 5g with the exception that the mixing tube is not present and one additional hydrocarbon fuel feed with the combustion products is mixed by the exhaust system. The combustion products poor in oxygen make a mixing tube through it superfluous that they use the stored hydrocarbons Make non-combustible so that they can be used later as unburned hydrocarbons during the expansion stroke are available after the initial combustion explosion. There are apparently several embodiments for the delivery of additional fuel, in which a cavity provided on the spark plug is used as in the embodiment of FIG. 5 i to provide the NO reduction of the present invention. Furthermore, the measure of the additional fuel supply can be used a general measure, which is described in connection with Figure 5h and in the utilization of the is composed of hydrocarbons stripped from the working cylinder.

To treat the exhaust gas from an incinerator, which is lean in fuel and contains unwanted NO, it is evidently necessary to get enough unburned hydrocarbons first and to accelerate the combustion so that the resulting products are like that Products delivered from a rich fuel incinerator. In a second step more unburned hydrocarbons are then added to effect the reduction of NO. In practice it turns out

that this two-step process actually occurs when the same total amount of unburned hydrocarbons is added to the exhaust products of combustion the first time and the combustion is accelerated.

In Figures 6 to 12 are different versions of Spark plugs shown, which are similar to those in Figures 5 i and 5 j

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are trained. In these embodiments, the hydrocarbon off-storage chamber designed as part of the spark plug assembly, so that they are threaded with a hole in the cylinder wall can be releasably connected. In this way it is possible to convert existing internal combustion engines.

In the embodiment of FIG and 102 are shown mounted coaxially on the porcelain insulator body 104 to be in the annulus between the insulator body and outer electrode 106 to form storage cavity 108. Ground during the compression stroke of the machine unburned hydrocarbons from the cylinder via the offset openings in plates 100 and 102 in FIG introduced the storage cavity. Because the storage cavity is isolated from the cylinder by the openings and because further If there is a lower temperature in the storage chamber because of its distance from the cylinder, unburned hydrocarbons become stored in cavity 108 until ignition of the fuel in the cylinder is complete. While of the engine's working stroke, the unburned hydrocarbons are then returned to the cylinder to reduce the To bring about reduction of the undesired nitrogen oxides (since the temperature, time and volume conditions in the cylinder is suitable for the effective reduction of nitrogen oxides). If necessary, by the fuel injector Fuel can be introduced directly into the storage cavity.

In the embodiment of Figure 7, the annular Storage cavity 116 between the insulator 118 and the outer Electrode 120 is formed in a part of the spark plug that is remote from the thread 118 a of the outer electrode 118. Through this the cavity is isolated from the cylinder of the engine and is at a desirably low temperature. As a result, the ignition of the hydrocarbons in the cavity 116 upon ignition of the fuel in the cylinder is avoided. Unburned hydrocarbons are released via an or

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several, through longitudinal bores 122 in the outer electrode 120 fed to and from the storage cavity 116 submitted. Optionally, a fuel injection device be provided in order to supply unburned hydrocarbons into the cavity 116.

In the embodiment of Figure 8, a groove 130 is on the The outer surface of the outer electrode 132 is formed between the threaded section 132 a and the enlarged section 132 b, which presses the sealing ring 134 onto the outer surface of the cylinder head. In this embodiment are essentially in Longitudinal grooves 136 are provided in the threaded portion 132 a, which connect the cylinder and the Produce memory cavity 131, the from the groove I30 and the Annular space is formed in the sealing ring 134. Possibly can fuel into the cavity through a conventional fuel injector be injected.

In the exemplary embodiment of FIG. 8, the groove I30 is in the Spark plug formed. It can be seen, however, that a similar groove is also found in the corresponding part of the threaded hole may be formed in the cylinder head either in conjunction with or as an alternative to the groove I30, so that the size of the storage cavity can be controlled in this way.

In the exemplary embodiment of FIG. 9, there is an annular bush 140 mounted concentrically on the outer electrode 142 between the threaded portion 142 a and the enlarged portion 142 b. Sealing rings 146 and 148 are placed between the bushing 140 and the enlarged electrode portion and the cylinder head are pressed together, respectively. This makes a ring-shaped Storage cavity 150 formed between the socket and the outer electrode part. Longitudinal grooves 152 in the threaded section I42 a form the connection between the storage cavity 150 and the cylinder of the internal combustion engine.

609 8.13 / 0372

As shown in Figure 10, the inner peripheral surface of the Bushing 160 may be provided with an annular groove 162 in order to increase the effective size of the cavity 164. The depth and breadth of the Grooves 162 are a means to control the size of the storage cavity. To the distribution and the efficiency of the coal water ^ - To increase substances in the storage chamber, the groove can be filled with a porous mass 166, for example sintered bronze as shown in Figure 11, so that a filter effect is achieved on the fuel.

In the embodiment of FIG. 12, the storage cavity 170 is formed by an annular groove or recess which is shown in FIG the end face of the enlarged section 172 a of the outer electrode 172 of the spark plug is formed. The outside diameter the groove 170 is smaller than the diameter of the sealing ring 174 »that between the enlarged electrode section 172 and the cylinder head is compressed. The connection between the storage cavity and the cylinder is made by longitudinal grooves 176 formed in the outer periphery of the threaded portion 172 b of the outer electrode are arranged.

In each of the spark plug embodiments, fuel injectors optionally be provided to a certain amount of fuel from a separate fuel supply to deliver the storage cavity.

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Claims (54)

Claims Methods for reducing the impurities, in particular the nitrogen oxides, from the low-oxygen combustion products of a combustion device for hydrocarbon fuels, wherein the combustion products contain an undesirable excess of nitrogen oxides, characterized in that that gaseous hydrocarbon compounds in the combustion products at a sufficiently high temperature in one Matched, selected, screened volumes are brought together, so that an acceleration of the reduction the nitrogen oxides and the NO to an acceptable one in a selected volume-based reaction time Level is reduced, the reaction time, volume and temperature being matched to the combustion device are. 2. The method according to claim 1, characterized in that the gaseous Hydrocarbon compounds in the combustion products are brought together at a sufficiently high temperature, that the products of combustion from the source of the products of combustion in a heated state in a selected, shielded Volume are introduced, and that the gaseous hydrocarbon is added in a sufficient amount, so that when the products of combustion and the gaseous hydrocarbons in the chamber with the selected volume a sufficiently high temperature are maintained, the appropriate reaction time to bring the level of NO to an acceptable level To reduce level, is matched to the requirements of the incinerator. 3. The method according to claim 2, characterized in that the Combustion products are heated as they enter the selected, shielded volume, so that the heat loss is compensated as the combustion products move away from the source of the combustion products, 509813/0372 - J _W - with the products of combustion at a sufficiently high level
Temperature are maintained. * 4. The method according to claim 1, characterized in that the gaseous hydrocarbons in the deoxygenated combustion products are brought together at a temperature sufficiently high that the unburned hydrocarbon compounds are provided in gaseous form in the shielded volume that serves as the source of the combustion products at a time after the NO has been generated by the combustion products is, where the
The relatively high temperature generated by the combustion is used to maintain the mixture at a temperature sufficiently high that the NO is reduced to an acceptable level in a reaction time which is matched to the shielded volume of the source of the combustion products. 5. The method according to claim 4 »characterized in that part of the fuel mixture, which is otherwise used for combustion, is stored in the shielded volume as unburned hydrocarbon compounds, and that the stored hydrocarbon compounds in
non-combustible form so that they can be used at a later time after the production of the combustion products. 6. The method according to claim 5 »characterized in that the stored hydrocarbon compounds are sprayed in non-combustible form into the combustion products after they have been generated in the selected volume
are. 7. The method according to claim 5, characterized in that the unburned hydrocarbon compounds sätzlichen from a supply source · is stored together with a portion which is otherwise used for the combustion of the fuel mixture in the shielded volume. 609613/0372 8. The method according to claim 4 »characterized in that.die Hydrocarbon compounds in gaseous form in the shielded. Volume injected from a separately timed source to make the hydrocarbon compounds therein available at a time after the Combustion products have been generated therein so that the NO therein is reduced. 9. Method according to claim 4 »characterized in that the hydrocarbon compounds are sprayed in gaseous form into the shielded volume at a point in time following the generation of the combustion products, the hydrocarbon compounds first being directed to a location with the K:> highest concentration of NO will, 10. The method according to claim 4, characterized in that a storage heat source in the path of the combustion products is arranged when these are expelled from the shielded volume to remove the products of combustion at a Maintain temperature that is high enough to keep the NO contained therein in the presence of the unburned hydrocarbons reduce off connections. 11. The method according to claim 10, characterized in that the storage heat source is supplied by the energy of the previous combustion. 12. The method according to claim 4, wherein the hydrocarbon fuel combustion device is initially to be operated in such a way that a fuel-lean combustion product with nitrogen oxides and an excess of oxygen is produced, characterized in that initially • at least one. Part of the fuel-lean combustion product is supplied with a certain amount of unburned hydrocarbon compounds which is sufficient to remove the excess oxygen and which thereby makes the resulting combustion product poor in oxygen. 509813/0372 13. Device for reducing impurities, in particular for reducing nitrogen oxides, from a low-oxygen one Combustion product of a hydrocarbon fuel incinerator, the combustion product having an excess of nitrogen oxides, characterized by means to a certain amount of unburned Mix hydrocarbon compounds with the low-oxygen combustion product and reduce the temperature of the To bring the mixture to a high enough value to bring the nitrogen oxides to their state of equilibrium in a To reduce reaction time and a volume that are matched to the combustion device. 14. Device for removing impurities, in particular nitrogen oxides, from low-oxygen combustion products a hydrocarbon fueled combustor, which in one mode of operation is an exceptional high concentration of nitrogen oxides generated at a given temperature, characterized by facilities, around the combustion products at a temperature of at least 2200 ° Rankine with a sufficient amount of hydrocarbons mixing for a time long enough to purify a reduction of some of the nitrogen oxides To effect nitrogen and thereby reduce the concentration of oxides to the equilibrium state. 15. Apparatus according to claim 13 or 14, characterized in that the temperature of the combustion products before mixing with the hydrocarbons is at least 2200 ° Rankine. 16. The apparatus of claim 13 or 14, wherein the temperature of the combustion products prior to mixing with the hydrocarbons is less than 2200 ° Rankine, characterized by facilities to bring the mixture to a temperature of to heat at least 2200 ° Rankine for a long enough time to convert at least some of the nitrogen oxides into reduce pure nitrogen. 509813/0372 17 · Device according to claim 16, wherein the heating device has a flame holder, characterized in that (a) the device for generating a flame on the flame holder a source of air (24), a source of fuel (27), a carburetor (26) to mix the air and fuel from these sources, and the mixture to be supplied to the flame holder in a desired state, and having an ignition device (38), to ignite the mixture to create the flame on the flame holder, (b) that means are provided for mixing the products of combustion with the gases generated by the flame is, causing the combustion products to an elevated temperature in the range of about 2200 ° to 2600 ° Rankine, and that (c) a container device (21) is connected to the heating device in order to store the heated combustion products record and hold them at an elevated temperature for a sufficiently long time so that the desired reduction in the concentration of nitrogen oxides takes place. 18. Apparatus according to claim 17 »characterized in that the container means (21) has an outlet at which an oxidation device (30) is connected to the carbon monoxide and unburned hydrocarbon components to oxidize in the gases discharged from the container device (21) via the outlet. Device according to claim 16, wherein the device operated by hydrocarbon fuel is an internal combustion engine, characterized in that the mixing device is the piston-cylinder arrangement of an engine, the piston wiping off part of the unburned hydrocarbon layer on the relatively cold cylinder walls during the exhaust stroke and the unburned hydrocarbons are mixed with the combustion products contained in the cylinder. 509813/037 2 20. The device according to claim 19, characterized in that the heating device has a heat storage element (80) in the
Cylinder (Figure 5h) in the path of the exhaust gas from the
Having cylinder, wherein the storage heating element (90)
are heated by the hot gases in the cylinder during the power stroke and the heat is given off to the combustion products during the exhaust stroke. 21. The apparatus of claim 15, wherein the hydrocarbon fuel operated device is an internal combustion engine, characterized in that a device which makes the combustion products in the cylinder of the engine oxygen deficient, is provided, and that the mixing device comprises a fuel injector to unburned hydrocarbon fuel in inject the cylinder of the machine at a time when the
the gases contained therein are low in oxygen. 22. The device according to claim 21, characterized in that the device which makes the combustion products in the cylinder low in oxygen has a carburetor which controls the fuel-air mixture supplied to the cylinder
controls. 23. Apparatus according to claim 21, characterized in that the means that the combustion products in the cylinder oxygen depletion, comprises a fuel injector that has an excess of fuel in the cylinder introduces. » 24. The apparatus of claim 15, wherein the hydrocarbon fuel operated device has an internal combustion engine, characterized in that the mixing device at least one chamber in the cylinder, either on the piston or on the cylinder of the engine is arranged to remove unburned hydrocarbon during the intake and compression strokes of the piston receives, and that the chamber for communication with the 509813/0372 Cylinder an opening with such, a size with respect to the Chamber has that when the fuel is burned in the cylinder, the combustion gases in the chamber without Ignition of the hydrocarbon contained therein are introduced, whereby the gases in the chamber are diluted and are made non-combustible, so that during the expansion stroke after combustion, the unburned hydrocarbons are released from the chamber and deal with the products of combustion to reduce the levels therein Mix nitrogen oxides. 25. The device according to claim 24, characterized in that the chamber (56) is arranged in the end face of the piston is. 26. The device according to claim 24, characterized in that the means forming the chamber in the cylinder the compression chamber are arranged above the top dead center (FIG. 5 c). 27. The device according to claim 24, characterized in that the devices forming the chamber on the cylinder are arranged outside of and in connection with the cooling chamber of the cylinder. (Figures 5d to 12) 28. Apparatus according to claim 24, characterized in that a venturi device (FIGS. 5 e and 5 f) is provided communicating at one end with the opening and extending coaxially from the opening into the chamber, to initially absorb the unburned hydrocarbon and then the products of combustion that produce the displace unburned hydrocarbons into the part of the chamber, surrounding the venturi device, and that the venturi device has a metering passage through which the unburned hydrocarbon is mixed with the combustion products as they occur during the expansion stroke exit the chamber. 509813/0372 24A5H7 29. The apparatus of claim 15, wherein the hydrocarbon fuel operated device is an internal combustion engine, characterized in that the mixing device at least one chamber on the piston or the cylinder that is in communication with the working chamber of the cylinder of the engine that.die chamber mixes the products of combustion after spark ignition of the fuel mixture in the working chamber of the cylinder that houses an unburned hydrocarbon source and device for mixing the unburned hydrocarbon with the combustion products in the chamber, wherein during the expansion stroke of the piston after combustion, the mixture of the combustion products with the hydrocarbons is introduced into the working chamber of the cylinder and raised to a temperature at which the reduction the nitrogen oxides turns into pure nitrogen. 30. The device according to claim 29, characterized in that the chamber device has an opening which with the Working chamber of the cylinder is in communication, and that a Venturi device is connected with one end to the opening and extends axially into the chamber, the venturi device having a lateral metering channel having one end connected to a supply for unburned hydrocarbon, with unburned hydrocarbon Hydrocarbon is mixed with the combustion products as they pass through the venturi step through (Figure 5 f). 31. The device according to claim 30, characterized by a one-way valve (65) between the hydrocarbon storage container and the venturi passage to remove the reservoir from the chamber during combustion of the gases in the working cylinder to isolate. 32. The apparatus of claim 29, wherein the machine is a four-stroke engine is, characterized in that the the chamber forming means has an opening which the 509813/0372 Connection between the chamber and the working chamber of the cylinder establishes that an inlet pipe with one end on the port is connected and extends axially therefrom into the chamber with the inlet tube between its Ends has a metering passage that an annular mixing wall means concentrically spaced around the inlet pipe is arranged to divide the chamber into two concentric sub-chambers that the mixing wall at least has an opening which establishes a connection between the sub-chambers, a valve normally the Hydrocarbon supply separates from the chamber, and that the valve device is connected during the intake stroke establishes between the hydrocarbon supply and the chamber and closes the free end of the inlet pipe so that , during the intake stroke hydrocarbon in the inner sub-chamber and during the time after the combustion Combustion products from the cylinder into the inner sub-chamber via the inlet pipe for mixing with the hydrocarbons are introduced, the mixture being stored in the outer sub-chamber and discharged into the cylinder via the inlet pipe during the expansion stroke of the piston so that the nitrogen oxides contained in the combustion products are reduced (FIGS. 5 f and 5 g). The apparatus of claim 24, wherein the machine is a four-stroke engine is, wherein a spark plug is mounted in an opening in the wall of the cylinder, characterized in, that the means forming the chamber has a wall which cooperates with the spark plug to form a chamber around the to form the isolated portion of the spark plug extending into the cylinder with the wall containing the opening (Figures 6 to 12). 34. Apparatus according to claim 33 »characterized by a Device for supplying unburned hydrocarbons to the chamber during the suction stroke of the piston (Figure 6 until 12). 609813/03 72 24A5H7 35. Apparatus according to claim 34, characterized in that the device for supplying hydrocarbons has a storage container for unburned hydrocarbons and a device with a one-way valve which normally separates the storage container from the chamber, the one-way valve at a predetermined time during the intake stroke of the Piston is actuated to allow the supply of hydrocarbon to the chamber. 36 · Device according to claim 24 with a storage container for unburned hydrocarbons, characterized by a carburetor for mixing the hydrocarbon with the exhaust gases of the cylinder, a line which introduces the hydrogen-exhaust gas mixture into the chamber, to measuring openings in the device forming the chamber , which establishes the communication between the chamber and the working chamber of the cylinder, and through a valve which normally separates the chamber from the carburetor, which valve is opened at a predetermined time during the intake stroke to supply hydrocarbons to the chamber. 37 · Device according to claim 13 with a combustion device for hydrocarbon fuel, characterized by a container in which the combustion products are considered to be low in oxygen Combustion products are generated. 38. Apparatus according to claim 37 with a fuel mixture supply means to supply combustible hydrocarbon mixture to the container for incineration. 39. Apparatus according to claim 33 »characterized by a Cavity in connection with the container for receiving a part of the combustible hydrocarbon mixture, which is to the Container has been dispensed to contain a sufficient amount of gaseous hydrocarbons in non-combustible form obtained to add them to the combustion products after the initial combustion explosion, thereby reducing the 509813/0372 2U5147 Reduction of nitrogen oxides is effected. 40. Apparatus according to claim 38, characterized by an additional Hydrocarbon fuel supply device to add hydrocarbon fuel to the combustion products in the container in non-combustible form after the initial one To feed combustion explosion. 41. Apparatus according to claim 38, characterized in that daiE the cavity communicating with the container is located immediately next to the ignition, so that the thereby to the Combustion products emitted, unburned hydrocarbon compounds in a mixture with the combustion products be released at the site of the highest concentration of NO. 42. Apparatus according to claim 38, characterized by a separate Hydrocarbon fuel supply device that adds the hydrocarbon to the combustion products in the container after the initial combustion explosion. 43. Apparatus according to claim 38, characterized in that a heating surface in the container in the path of the combustion products, which are ejected from the container, is arranged, wherein the heating surface is heated by the combustion explosion (Figure 5h). 44. Apparatus according to claim 13 _f, characterized in that a second container is provided to receive the combustion products from the first container in which the combustion products are generated, and by a heating device in this container to increase the temperature of the combustion . to raise products to at least the temperature in the container in which the combustion products are formed, before they are delivered to the second container. 509813/0372 45. Device for reducing nitrogen oxides in exhaust gases an internal combustion engine, in particular a spark plug, which at one end is in an opening in the cylinder head of an internal combustion engine is mountable, which generates combustion gases with a low nitrogen oxide content, the spark plug has an inner electrode and concentrically therewith a tubular insulator and a tubular outer electrode, wherein the outer electrode has an externally threaded portion that engages the spark plug in the cylinder head opening characterized by means defining a storage cavity defined by the cylinder is separated when the spark plug is screwed into the cylinder head opening, and by at least one passage, which establishes a connection between the cylinder and the storage cavity, so that during the compression stroke the internal combustion engine supplied a certain amount of unburned hydrocarbon material to the storage cavity this hydrocarbon material is supplied to the cylinder after ignition of the engine during the expansion stroke is used to reduce the nitrogen oxide content in the gases in the cylinder au (Figures 6 to 12). 46. Apparatus according to claim 45 »characterized in that the insulator has a shape such that it forms an annular cavity at one end of the spark plug which is concentric to the inner and outer electrodes next to the cylinder of the internal combustion engine (Figures 6 and 7). 47. Apparatus according to claim 46, characterized in that the device forming the storage cavity is at least has an annular plate concentric with the insulator and the outer one at one end of the spark plug Electrode is arranged, wherein the plate contains a plurality of openings forming passages so that the Spark plug chamber forms the storage cavity (Figure 6). 509813/0372 48. Apparatus according to claim 471 characterized by at least an additional ring plate, which is arranged concentrically around the insulator parallel to the first ring plate, wherein the additional ring plate has a plurality of openings opposite to the openings in the first ring plate are offset so that the plates separate the storage cavity from the cylinder. 49. Apparatus according to claim 45 »characterized in that the device forming the storage cavity on the spark plug above the threaded section and apart from that Spark plug end is arranged (Figures 7 to 12). 50. Apparatus according to claim 49 »characterized in that the storage cavity has a cavity between the insulator and the outer electrode, and that a passage is arranged as a longitudinal bore in the outer electrode and extends longitudinally from one end thereof to the storage cavity (Figure 7) 51. Apparatus according to claim 49 »characterized in that the outer electrode has an enlarged part, and that the spark plug has a sealing device which is concentric rests on the outer electrode to form a seal between the enlarged portion of the outer electrode and to manufacture the cylinder head when the spark plug is inserted into the cylinder head opening (Figures 8 to 12). 52. Apparatus according to claim 51 »characterized in that the storage cavity has an annular groove in the outer circumference of the outer electrode between the seal and the threaded section, and that the passage has at least one groove » which extends in the longitudinal direction over the length of the threaded section and is provided therein (Figures 8 to 12). 509813/0372 ~ ⁴⁸ ~ 2445H7 Device according to Claim 51, characterized in that an annular bushing is arranged concentrically at a distance from the outer electrode between the seal and the one spark plug end, that an auxiliary seal is placed concentrically around the outer electrode in order to create a seal between the bushing under pressure .e and the electrode head, the annular space between the socket and
the outer electrode forms the storage cavity, and that the passage has at least one groove which extends into
Extends longitudinally over the threaded portion and thereby establishes a connection between the cylinder and the storage cavity. 54. Apparatus according to claim 53 _f, characterized in that the socket has a recess on its inner circumference, whereby the size of the recess influences the volume of the storage cavity. 55 · Device according to claim 51 »characterized in that the surface of the enlarged section of the outer
Electrode, which is opposite to the cylinder head, has an annular groove, the diameter of which is smaller than the diameter of the seal, wotoei the annular groove forms the storage cavity, and that the passage has at least one groove which
extends in the longitudinal direction over the threaded portion and is incorporated therein, whereby the connection between the cylinder and the Singnut is made. 509813/0372 Blank page