DE2335101A1 - COMBUSTION ENGINE - Google Patents

Description

AFTER QERBCHTI

Patent attorneys

Dr. Ing.Walter Abitz
Dr. Dieter F. M ο rf
Dr. Hans-A. Browns

8 Munich 8b, Pifcnzenauarstr. 28

HONDA GIKEN KOGYO KABUSKIKI KAISHA

5,5-chome, Yaesu, Chuo-ku Tokyo, 104, Japan

Internal combustion engine

The invention relates to four-stroke internal combustion engines and, above all, to the reduction of nitrogen oxides (NO), the unburned ones Hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gases of such engines. The present Registration is an additional registration to the parent registration P 22 59 286.5.

A four-stroke internal combustion engine has been proposed which having at least one piston receiving cylinder, the or each such cylinder having one partially through the main combustion chamber bounded by the piston, one with a Ignition device equipped with the main combustion chamber Auxiliary combustion chamber connected by a flame channel and the auxiliary combustion chamber is essential is smaller than the main combustion chamber, as well as a device for supplying a relatively lean air-fuel mixture to the main combustion chamber, and a device for supplying a relatively rich air propellant

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having substance-Gemisehes to the auxiliary combustion chamber.

The present invention relates to a four-stroke internal combustion engine, the at least one piston receiving Has cylinder, the or each such cylinder having a main combustion chamber partially delimited by the piston, one equipped with an ignition device and connected to the main combustion chamber via a flame channel has standing auxiliary combustion chamber and the auxiliary combustion chamber is much smaller than the main combustion chamber and limited by a thin-walled metal sleeve is, in the wall of which an opening representing the flame channel is formed, as well as a device for supply a relatively lean air-fuel mixture to the main combustion chamber and means for supplying a relatively rich air-fuel mixture to the auxiliary combustion chamber having the main combustion chamber, the auxiliary combustion chamber and the flame channel in the manner are arranged to each other and have such dimensions that when the engine is operating during each intake stroke and the following compression stroke a massively rich air-fuel mixture in the main combustion chamber in the Proximity of the flame channel is formed, thereby causing the mixture in the main combustion chamber after ignition gradually and substantially throughout the entire stroke of the piston with a low peak combustion temperature burns.

The invention also relates to a method by which a four-stroke internal combustion engine operates, the at least one a piston receiving cylinder, the or each such cylinder being defined in part by the piston Main combustion chamber, one equipped with an ignition device and connected to the main combustion chamber auxiliary combustion chamber communicating with a flame channel with the auxiliary combustion chamber being essential

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klo.i ^ er..j-r.t as the main combustion chamber and through a thin-walled; Hetallhülse limited -is, in the VJand a the opening representing the plasma channel is formed and a device for supplying a relatively lean air-fuel mixture. in the Hauptverbreimungskanraer and one Einriehtm.g for supplying a relatively rich air-fuel mixture in the auxiliary combustion chamber, the method comprising producing a massively rich air-fuel mixture in the main combustion chamber at the height of the flame channel while working the Iiotor each intake stroke and subsequent compression stroke, which causes the mixture in the main combustion chamber gradually and essentially over the entire working stroke of the piston with a low Peak combustion temperature burns.

According to the invention, the three above-mentioned are undesirable Components of the exhaust gases through improvements in the underlying combustion process of the engine decreased. A reduction in the production of NO is achieved by reducing the peak temperature of the combustion is kept low. The combustion temperature, on the other hand, becomes kept high enough for a longer period to reduce the emission of HC. The CO emissions will be reduced by the fact that there is an excess of oxygen in the lean mixture supplied to the main combustion chamber consists.

To reduce the NO production, the peak temperature of the combustion under certain operating conditions in the Controlled in a manner that it does not exceed 1200 C in the main combustion chamber. In comparison, the Peak combustion temperature in conventional four-stroke gasoline engines exceed 2000 ° C at relatively high loads.

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ORIGlNAL BATHROOM

22.107-171

As for reducing HC knee emissions, it is common knowledge that the combustible mixture even when a conventional engine is under the best conditions operated near the relatively low-temperature Cylinder walls do not burn completely. Me oxidation of HC v; is favored when the combustion temperature is around Exceeds 800 ° C. The combustion temperature in a conventional four-stroke Bonsin engine is reached after ignition of the mixture quickly becomes high. Value and decreases rapidly with the expansion of the combustion gases. The temperature at which one Combustion of HC actually takes place, consequently exists in a conventional engine only for a very short period of time, which leads to the discharge of unburned HC originating from the area near the cylinder walls. To reduce of the HC emissions is therefore according to the invention Combustion temperature in the cylinder kept at a relatively high value as long as possible.

It is well known that CO emissions are reduced when the combustible mixture is leaner than the stoichiometric one Is air-fuel ratio. Such a lean one However, the mixture has a very poor ignitability, which causes unstable operation of the engine; in extreme cases, the mixture sucked into a cylinder is expelled without combustion. To reduce the CO emissions it is therefore necessary to improve the combustion process in such a way that the engine can with a very lean, flammable mixture can operate in a reliable manner.

The NO emissions are greatest when the engine is powered by a high load, and the HC emissions are greatest when idling or at low loads.

The specified time and temperature conditions to reduce NO, HC and CO emissions require an extremely long

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same combustion of the lean, combustible air-fuel mixture. There must also be a very strong ignition source in order to destroy the otherwise lean, combustible mixture burn. In addition, the speed of propagation regulated according to the load on the engine in order to obtain the desired combustion temperature.

Known engines have been proposed which attempt to reduce the production of unburned hydrocarbons in the exhaust gases of the engine by increasing the combustion temperature and pressure within the main combustion chamber and using an ignition source capable of completing combustion within 10 ° or 15 ° of the crank angle is designed after the top dead center of the piston. Such proposed engines can reduce HC production, but only at the expense of producing a greater amount of NO. Because of the mutually contradicting demands on the combustion temperature, such known engines were not able to reduce the generation of Ν0 _χ and at the same time of HC. By reducing the peak temperature responsible for the generation of NO while maintaining a relatively high temperature for a relatively long period of time during substantially the entire stroke of the piston, the present invention solves this conflict.

A preferred embodiment according to the invention contains consequently a four-stroke internal combustion piston engine with spark ignition, which has a main combustion chamber and an auxiliary combustion chamber for the or each cylinder, wherein the chambers are connected by a flame channel or a so-called torch nozzle. Facilities such as Legs first inlet opening of a carburetor convey a lean air-fuel mixture to a valve equipped with

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and inlet duct leading to the main combustion chamber and additional facilities such as B. a second inlet opening of a carburetor promote a rich air-fuel device to an intake port equipped with a valve and leading to the auxiliary combustion chamber. Separate throttles in the two carburetor inlet openings cause a change in the amount supplied to each of the chambers Amount of mixture. The with- valved and to the Channels leading to both chambers are opened and closed in a certain sequence in the manner that During the intake stroke of the piston, a lean mixture is drawn into the main combustion chamber and a rich one Mixture into the auxiliary combustion chamber and through the auxiliary combustion chamber and the torch nozzle is sucked into the main combustion chamber. This fat mixture that is inside the main combustion karamer penetrates the lean mixture, disperses to form a local zone that in the main chamber near the torch nozzle a massive contains rich mixture. The following compression stroke of the piston causes reverse movement of part of the Zone with the massively rich mixture from the main combustion chamber back through the torch nozzle and into the auxiliary combustion chamber. If the piston is at or near top dead center at the end of the compression stroke, is the air-fuel mixture in the auxiliary combustion chamber still fat, but its fatness is to some extent during the backward movement of part of the zone with the massively rich mixture in the auxiliary combustion chamber been weakened. At the same time, the remaining part of the zone with the massively rich mixture remains under compression the main combustion chamber and near the torch nozzle such a position and is richer than the relatively lean, compressed air-fuel mixture in the center of the main combustion chamber. The remainder of the zone remaining in the main combustion chamber during compression the massively rich mixture is referred to as a "mixture cloud".

BATH ORIGINAL

The ignition of the compressed air-fuel mixture in the Auxiliary vei-bx'erinungskammer is through. Igniting one. spark plug reached, the electrodes of which are located within the auxiliary combustion chamber are located. The relatively rich mixture ignites almost immediately and directs a flame through the torch nozzle, to ignite the mixture cloud in the Hauptverbrennuηgskearner su. The dimensions of the components and the greasiness of the mixture cloud cause a low peak temperature and a gradual, extending over at least 180 ° of the crank angle Burning of the lean mixture over the working stroke of the piston. Although the relatively high, longer time sustained temperature does not peak at a high level, it reduces the production of unburned hydrocarbons in the exhaust gases and oxidizes because of the excess oxygen in the main combustion chamber most of the carbon ion oxide to carbon dioxide.

In order to achieve the best results, the mixture cloud must have a suitable size, the volume ratio must of the two chambers are within certain limits and the cross-sectional area of the torch nozzle must be within certain Limits to the size of the auxiliary combustion chamber be proportional. In addition, the ratio

- Weight of the items sucked into the auxiliary combustion chamber

Weight of air drawn into the main combustion chamber

controlled by separate carburettors, each of which supplies one of the 'chambers. To control the positions of your throttle valves From idling to full load, the carburettors are coupled to one another via a control disc mechanism sinus. The ratio / v is made larger at idle and smaller at full load. As a result, when idling it becomes a large one Mixture cloud is required, since a large amount of residual gases compared to the fresh filling prevents the combustion.

difficult, what otherwise' too high HC emissions with low NO, emissions would result.

At full load, the cloud must be made small in order to reduce the peak temperature and thus the ITO _y emissions. Also to form a Gerni cloud with the required air-fuel ratio in the main combustion chamber, α (air-fuel ratio of the mixture conveyed to the auxiliary combustion chamber) and α (air-fuel ratio of the mixture conveyed to the main combustion chamber) must be in relation to the jFresh air flow rates of the auxiliary combustion chamber and the main combustion chamber can be regulated.

Other preferred but optional features of the present invention are as follows:

The rich air-fuel mixture that the auxiliary combustion chamber is to be supplied, is preferably heated beforehand by exchanging heat with the hot Exhaust gases emerging from the main combustion chamber is passed on, and in this way essentially the all of the fuel in the rich mixture is vaporized prior to its entry into the auxiliary combustion chamber.

To extend the duration of the combustion, the turbulence in the main combustion chamber is preferably increased as much as possible so that the cloud is not dispersed, and the state of minimal turbulence is thereby 'favored, that all "pinch" areas are reduced as much as possible. That is, the one formed over the cylinder The top part of the main combustion chamber has the same circular shape and without any significant irregularities Big as the cylinder.

A spark plug representing the ignition device is preferred

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wise arranged bo that their electrodes are not contaminated by the impact of the rich mixture when it is introduced into the auxiliary combustion chamber, and that the spark on the electrodes is not blown out by the gas flow from the main combustion chamber at the end of the compression stroke.

The cross-sectional area of the torch nozzle is preferably larger formed as the cross-sectional area of the venturi in the carburetor, which carries the rich mixture to the auxiliary combustion chamber promotes precise regulation of air flow at full throttle or at near full throttle throughout Ensure the service life of the motor.

The main combustion chamber formed between the cylinder head and the piston when it is at top dead center is preferably not symmetrical, but has a greater depth on one side of the center line and is near the area of greatest depth with the torch nozzle tied together.

The axis of the torch nozzle preferably intersects the axis of the cylinder, directly below the head of the cylinder in its position at the top dead center (TDG-top dead center) ·.

In conjunction with the drawings, an exemplary embodiment is described below of the invention described. Show it:

Fig. 1 in a diagram and partially in cross section Side elevation showing the important parts of the inventive Internal combustion engine represents

Figures 2, 3 and 4 are sectional views along lines 2-2, 3-3 and 4-4 of Fig. 1,

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Figure 5 is a partial sectional view taken along line 5-5 of Fig. 8,

6 shows a side elevation on an enlarged scale a part of Fig. 1, with a timing disc coupling for connecting the throttle nozzles of the two carburettors is shown,

7 shows the sequence of the combustion process in a diagram of the engine shown,

8 shows the underside of the cylinder head above the main combustion chamber, the position of the flame duct or the torch nozzle relative to the valves of the main combustion chamber is pictured,

9 to 17 in a schematic representation the workflow during the suction, compression. and work cycle, which generate the mixture cloud, showing how the mixture cloud promotes gradual combustion,

18 is a graph showing the relationship between the emission characteristics and the air-fuel ratio s se s,

19 shows a graph in a graph the cylinder gas temperature over the crank angle and

Fig. 20 shows in a diagram how the increasing load on the engine, the relative weights of the main chamber and influences the air supplied to the secondary chamber.

Reference is now made to FIGS. The internal combustion engine has one or more pistons 1, the or each piston being a movable wall of the corresponding one Main combustion chamber 2 represents. A flame channel or

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a so-called torch nozzle 3 extends between the Main combustion chamber 2 and an auxiliary combustion chamber 5, the latter with an ignition device in the form of a Spark plug 4 is equipped. One to the main combustion chamber 2 leading inlet port 6 is through an inlet valve 9 controlled and one to the auxiliary combustion chamber 5 The leading inlet channel 7 is controlled by an inlet valve 10. One leading away from the main combustion chamber 2 Outlet channel 8 is controlled by an outlet valve 11. The three valves 9> 10 and 11 are arranged in the cylinder head and are by known, including a camshaft Facilities operated.

The air supplied through an air filter 13 is mixed with the fuel in a main carburetor 14 and an auxiliary carburetor 15, and the separable mixtures thus produced flow through a main inlet pipe 16 and an auxiliary inlet pipe 17. A relatively rich mixture is supplied from the carburetor 15 to the Inlet pipe 17 out. The spark plug 4 ignites the relatively rich mixture in the auxiliary ^{combustion chamber 5 and} causes a flame to be directed through the torch nozzle 5 in order to ignite the relatively lean mixture in the main combustion chamber 2. The exhaust gases from the main combustion chamber 2 flow through the outlet duct 8 and an outlet insert pipe 18 and serve to heat the rich, combustible mixture in the pipe 17 in order to prevent fuel condensation on the walls of the duct 7 and the auxiliary combustion chamber 5. The exhaust gases from the insert pipe 18 flow out through an insert pipe 19 within an exhaust manifold 21.

The main combustion chamber 2, the torch nozzle 3 and the Parts forming the auxiliary combustion chamber 5 are shown in FIG. 1 in the form of a diagram, and an actual embodiment of these parts is shown in Fig. 5 (the Main inlet valve 9 has been made for the sake of clarity

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in, F-IiJ <·. ^r i ^ yrer ^ elo ssen).

The cylinder head 23 is by hcr): common, not shown Means attached to the Kotorblock 12, and the usual seal 24- is clamped in between. Between the head of the Piston 1 and a curved surface 26, which has a recess opposite the head piece of the piston in the :) cylinder head 23 represents the main combustion chamber Parts of this main combustion chamber 2 are formed by the heads of the inlet valve 9 and the outlet valve 11 are formed. The recess in the cylinder head is not symmetrical, but has its greatest depth in the area of the torch nozzle. The recess has a circular edge that with the Cylinder bore 25 essentially coincides.

The auxiliary combustion chamber 5 is through a thin-walled, Cup-like sleeve 29 and a spark plug recess 28 limited. The free space 48 between the cup 29 and the walls 27 of a cavity in the cylinder head 23 is so small that it influences the volume to a negligible extent. The head of the intake valve 10 forms a wall of the auxiliary combustion chamber 5 · The bowl 29 is covered by a heat-insulating Elements 31 and 32 clamped end flange 30 held in position. The bowl 29 has a first opening 3 »which delimits the above-mentioned torch nozzle, and a second opening J4- that is connected to the spark plug recess 28 is in connection. A comparatively large opening 3a is formed in the cylinder head in such a way that that part of the cup 29 is directly exposed to the main combustion chamber 2, which has the advantage that the bowl warms up quickly during a cold start.

As shown in FIGS. 9 to 11, the intake stroke sucks of the piston 1 a rich mixture into the auxiliary combustion chamber 5 and through the torch nozzle 3 into the main combustion chamber 2. This rich mixture 60 penetrates the lean, of

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BATH ORIGINAL

de: i inlet port 6 trains introduced mixture 63. This distribu-j of the rich mixture £. ") In the lean mixture 63 forms a local area 61 which contains a moderately rich mixture. Diesex ¹ Zerstreiuingavorgang the rich mixture in the lean mixture wets during the whole intake stroke continues. Fig. 11 This local area 61 containing a moderately rich mixture is richer than the lean mixture 63 but not as rich as the mixture 60 introduced into the auxiliary combustion chamber.

During the compression stroke shown in FIGS. 12 and 13 of the piston flows part of the massively rich mixture 61 in the vicinity of the torch nozzle 3 back through the torch nozzle 3 and into the auxiliary incineration chamber 5 · As a result the mixture in the auxiliary combustion chamber is compared leaner with its original fatness. If the piston 1 is immediately before ignition, as shown in Fig. 13, approaches top dead center, the following mixtures exist in the chambers:

(a) A relatively rich mixture in the auxiliary combustion chamber 5 near the spark plug electrodes.

(b) A lean mixture 63 in the greater part of the main verb r ening chamber 2.

(c) A local area 64 with a massively rich mixture, which is referred to as a mixture cloud.

Ignition caused by a spark between the spark plugs of the electrodes ignites the rich mixture 62 in the auxiliary combustion chamber 5 »when piston 1 is near top dead center. The flame passes through that Torch nozzle 3 in the main combustion chamber 2 as it is is shown in FIG. As shown in Fig. 15, the mixture cloud 64 continues to burn continuously while the piston 1 moves downwards during the work cycle

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we ^ t. The burning of the gene cloud 6 ^; ; - causes gradual burning of the lean mixture Gy. The gradual burning continues throughout the entire working cycle, as shown in FIGS. 16 and 17. The gradual combustion, which lasts throughout the working cycle, has two very important effects relatively high combustion temperature of more than about 800 ° C. during the entire working cycle and at least part of the exhaust cycle. The relatively low peak temperature reduces NO production as well as possible, and the relatively long duration of combustion at a sustained high temperature above about 800 ° C reduces HC production as much as possible.

The volume of the auxiliary combustion chamber 5 has an important relationship to the volume that the main combustion chamber has when the piston 1 is in the top dead center position. If the volume of the auxiliary combustion chamber 5 is large compared to the volume of the main combustion chamber 2, efficient combustion of the lean mixture in the main combustion chamber cannot be expected, since the size of the mixture cloud 64 formed at the end of the compression stroke must be small, to maintain the overall lean air-fuel ratio. The flare energy is also too great, which leads to rapid combustion, a high peak temperature and large NO emissions. On the other hand, the auxiliary combustion chamber 5 i ^m compared to the volume of the main combustion chamber 2 is too small, the performance of the directed through the torch nozzle 3 torch is so low that the lean mixture 63 is not completely burned in the main combustion chamber. The best results were

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achieved if .dos the volume of the auxiliary combustion chamber 5 between ^L j > a and 12% of the total volume of the combustion chamber 5 and the main combustion chamber 2 with the piston in the top dead center position.

Likewise, the flow rate of the through the Torch nozzle 3 passing mixture during the compression stroke is reduced when the cross-sectional area between the auxiliary combustion chamber 5 and the main combustion Skammer 2 extending torch nozzle is too big, whereby the distribution of the rich mixture becomes less, and although the mixture cloud 64 becomes relatively richer, is their size is too small to cause effective combustion of the lean mixture 63 in the main combustion chamber 2. On the other hand, if the cross-sectional area of the torch nozzle 3 is too small, the flow velocity becomes of the mixture passing through the torch nozzle so large that the extent of the dispersion of the mixture becomes excessively large and consequently no effective mixture cloud is formed which would lead to a suitable spread the combustion is sufficient. The best results have been obtained when the narrowest cross section is the

2 torch nozzle 3 between 0.04 to 0.16 cm per cubic centimeter of the volume of the auxiliary combustion chamber.

To reduce HC and CO emissions as much as possible there is essentially complete combustion of the lean air-fuel mixture in the exhaust gases necessary in the main combustion chamber and this feature of essentially complete combustion is obtained by properly aligning the central axis 35 of the bore forming the torch nozzle 3, i. H. through the Favored direction of the central axis of the flame passing through the torch nozzle during operation. Good results have been obtained when the axis 35 is through the center point the upper piston surface or through a point

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immediately below it, with the Kolbon is in its upper to dpun lit position.

The relationship

Weight of the air sucked into the auxiliary combustion chamber

is controlled by carburetors 15 and 14 working in the way are coupled together that the desired ratio of the air weights for each operating condition from idle to Full throttle is generated. This ratio changes significantly from the idle position to the full throttle position. According to 6 is the carburetor 15 with an arm 40 actuated Throttle valve. 39 equipped. Similarly, the carburetor 14 is equipped with a throttle valve 41, which is actuated by an arm 42 extending from a cable 4J. The arm 42 has a cam surface 44 on which engages the eccentric roller 45 attached to the arm 40. A spring 46 holds the roller 45 against the cam surface 44-, The ratio of the extent of the opening of the Auxiliary throttle valve 39 compared to the opening of the Main throttle valve 41 is determined by the shape of the cam surface 44. In the illustrated embodiment, the Angular movements of the main throttle valve 41 and the auxiliary throttle valve 39 during the initial opening stages. When the opening of the main throttle valve 41 however, as it increases, the extent to which the opening of the auxiliary throttle valve 39 increases (see FIG. 20) is decreased.

When the engine is working and especially during the intake stroke a lean mixture is sucked from the carburetor 14 through the inlet valve 9 into the main combustion chamber and at the same time is from the carburetor 15 through the auxiliary inlet valve 10 sucked a rich mixture into the auxiliary combustion chamber 5. As mentioned above, this is the air-to-fuel ratio of the combustible mixture in the auxiliary

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Combustion chamber 5 leaner than before at the point of ignition ratio generated by the carburetor 15. On the other hand it is Air-fuel ratio of the main combustion chamber remaining mixture cloud 64 at approx time of combustion richer than the ratio of the lean, from the main carburetor 14- supplied mixture 63 · The degree of change in the air-fuel ratio the main and auxiliary incineration chambers is determined by the quantities of lean and rich mixtures sucked into the two combustion chambers. To run the internal combustion engine with a mixture of overall ratio of air to fuel to operate, it is therefore necessary to adjust the value of the opening ratio between the main throttle valve 41 and the Auxiliary throttle valve 39 to change in order for different Throttle orifices to change the amount of the mixture introduced into the main and into the auxiliary combustion chamber.

The opening ratio between the main throttle valve 41 and the auxiliary throttle valve 39 can thus be kept substantially constant in the areas of partial opening, -um a large mixture cloud "in the main combustion chamber to produce, thereby achieving complete combustion of the difficult-to-ignite, lean mixture that contains residual gases in such opening areas. In the Areas with a further opening of the main and the auxiliary throttle valve is an enlargement of the opening of the auxiliary throttle valve 39 compared to that of the main throttle valve 41 reduced to substantially complete burn and a low peak temperature ensure that generates as little HC and NO as possible.

Ji.

The combustion in the main combustion chamber 2 is said to be extraordinary are slow and gradual and it is therefore necessary to prevent excessive turbulence, to avoid that the mixture cloud is dispersed. For this reason, the cavity delimited by the wall 26 has

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in the cylinder head a very large diameter, which with the diameter of the cylinder bore 25 almost coincides. When the piston reaches top dead center, there is consequently very little "pinch" area from which at the end of the compression stroke gas has to be expelled very violently. The main fame cam is .in the way is designed and sized to create very little turbulence and has the feature of a very small "squeeze" area is in this context important. Moreover, the torch nozzle 3 is in the way arranged that the fat, through it into the main combustion chamber sucked in mixture nxGht thoroughly with the lean mixture sucked in through the inlet valve 9 is mixed.

The thin-walled cup 29 has a U-shaped cross section and is preferably made of heat-resistant material, such as. B. made of stainless steel. He preferably has one Thickness of about 2 mm. With the exception of the spark plug recess 28, the thin-walled cup 29 constitutes the outer limit of the auxiliary combustion chamber 5. The cup 29 is constructed and fixed in such a way that it can be used during operation of the engine remains hot, since the cup covers the walls of the cylinder head 23 for most of its length not touched, which is cooled by water channels 47. Of the Room 48 between. the thin-walled cup 29 and the surrounding engine head walls 27 can optionally be heat insulating material to be filled. It was, however also achieved good results if this space was left empty. The thin-walled bowl has a low heat capacity and is thermally insulated from the engine walls in such a way that the bowl is immediately removed when the engine is started is heated and then kept at a relatively high temperature while the engine is running. The hot bowl prevents condensation of the fuel admitted into the auxiliary combustion chamber 5 through the valve 10

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and thereby contributes to the reduction of HC emissions KeItstart at.

The exhaust gases are usually at a higher temperature than a conventional engine and contain an excess of oxygen so that the oxidation reactions continue in the exhaust system. Likewise, the auxiliary inlet duct leading to the valve 10 to reach a more complete evaporation of the inlet mixture than in conventional engines is kept at a higher temperature. Immediately after starting the engine, the exhaust pipe heats up and this heat is used to improve the properties of that supplied to the auxiliary combustion chamber 5 Mixture used. To the temperature of the rich, flammable mixture at the time of reaching the Auxiliary combustion chamber 5 between 140 ° C and 350 ° C closed hold, the rich mixture will exchange heat with directed to the exhaust gases. To avoid pre-ignition, the temperature should not exceed 350 G. It is advantageous to combine the exhaust pipe and the inlet pipe for the auxiliary combustion chamber 5 as one unit build to make them as thin as possible for maximum heat transfer, especially under cold start conditions. In order to reduce the HC emissions as far as possible, it is also desirable to have the exhaust ducts open to all Keep times hot. However, since the exhaust line heats up to around 800 ° G while the engine is running, its strength is reduced and it can suffer mechanical damage. In addition, the radiant heat tends and the heat transferred to the carburetors tends to boil the fuel inside the carburetors, resulting in incorrect operation of the engine.

For these reasons, the auxiliary inlet pipe 17 and 17 have the outlet tube 18 has a common wall 50 which is made of a relatively thin metal to facilitate heat transfer

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is made as it γ.ώ "be et en in the; I ¹ Mo 1 to 4 shown XBt. According to! '' ig. 2 and 3 we rl the gerr.einsai'ia V / π η el by the amalgamation of Parts of the tubes 17 and 19. A relatively open housing 51 encloses the thin-walled heat transfer tubes 17 and 19 and is attached by conventional means to the portion of the cylinder head 23, where the inlet and outlet ducts are located. thin-walled heat transfer insert ears from the destructive vibrations of the riotor and the vehicle and reduces the heat transfer to the carburettor as much as possible.

The position of the spark plug 4 is chosen such that its electrodes 49 are located outside the hot cup 29 and outside of the flow path of the rich mixture between the valve 10 and its immovable seat penetrates into the interior of the cup 29. In this way, the electrodes 49 are removed from contact with any Fuel droplets protected from being in the rich mixture may be included. Also, the spark plug electrodes are arranged so that there is no direct "line of sight" path through the torch nozzle 3 and the bowl opening J4 to the Electrodes.

In this way, the strong flow, which during the compression stroke of the piston 1 from the main combustion chamber, calls 2 is directed to the auxiliary combustion chamber 5, does not produce such a strong gas surge that the spark between the electrodes 49 will misfire by blowing out the spark could be caused. The axis 35 of the torch nozzle 3 is directed towards the upper part of the auxiliary combustion chamber 5, while the one with the spark plug recess 28 in Connected opening 34 lies outside this axis. Accordingly, the spark plug 4 generates the spark without any substantial risk of blowout. The lower rounded part of the bowl 29 forms a collecting container 67 to collect all un-

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evaporate ben collecting fuel droplets in a basin. Such drops of liquid can be calibrated when starting, before the engine is v / poor, accumulate and the droplets are prevented in this way from entering the main combustion chamber 2 and to increase the HC emissions through incomplete combustion.

It is important that the smallest cross-sectional area of the torch nozzle 3 is larger than the smallest cross-sectional area the venturi inlet opening 37 in the carburetor 15 for the Auxiliary Combustion Chamber 5- When the engine is working at near full load, the amount of rich, combustible the Auxiliary combustion chamber 5 supplied mixture can be determined by the size of the Venturi inlet opening 37, and similarly, the amount of the lean combustible mixture supplied to the main combustion chamber 2 should be determined by the size of the Venturi inlet opening 38 be. After some operating time, impurities, including carbon, accumulate on the band of the torch nozzle 3. Discharge of the torch nozzle 3 due to the accumulation of impurities including carbon would reduce the risk Limit the amount of rich, combustible mixture that the auxiliary combustion chamber 5 can reach. This restriction would in turn the mutual coordination between the rich mixture supplied by the carburetor 15 and eliminate the lean mixture supplied by the carburetor 14. The smallest cross-sectional area of the Venturi orifice 37 in the carburetor 15 is therefore made smaller than the smallest cross-sectional area of the torch nozzle 3.

The overview of FIG. 7 shows details of the combustion process when operating a motor according to the invention. This overview shows for each position of the crank angle the pressure and temperature curves of the combustion gas in the main combustion chamber when the main and auxiliary combustion chambers appropriate air-fuel mixtures supplied

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will. The temperature values apply to the in l ^? ig. 5 ¹¹ G "designated point or its Ilachborbereich. The point A on the pressure curve represents? The starting point of propagation of the pressure in the main combustion chamber 2 dai", the sverbrennungskanimer in the auxiliary is produced 5 by the ignition and combustion of the rich mixture. This Pressure rise continues up to point B.

Point A ¹ on the temperature curve corresponds to point A on the pressure curve. The low temperature at point A 'means that up to this point the planmia front has not yet reached the main combustion chamber. Point B ¹ on the temperature curve corresponds to point B on the pressure curve at which the gas temperature in the main combustion chamber has increased after the flame has spread from the auxiliary combustion chamber to the main combustion chamber. In other words, the combustion in the auxiliary combustion chamber 5 is completed at point B or B ¹ and the plasma front has spread into the mixture cloud 64 in the main combustion chamber 2 in the vicinity of the torch nozzle 3. The combustion rate up to point C of maximum pressure is relatively high, which leads to a temperature rise between points B 'and C'. After the maximum point C, at which the piston has started its downward movement, the pressure also decreases. However, the temperature continues to rise after point C, which means that the combustible mixture in the main combustion chamber 2 has not yet completed combustion, and the remaining mixture continues to burn gradually during the downward movement of the piston.

The big difference in the burn rate immediately before point C compared to that after Point C comes from the other air-fuel ratio in the combustible mixture in the main combustion chamber

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<5

near the Faokeldüse j. The combustion in the main combustion chamber 2 continues during the downward movement dos ELo Ib en ε and leads to the Tempcrcturmayimun at point D ¹ that of a conventional internal combustion engine, in which the temperature maximum is generated no later than 20 to 30 after top dead center. The point D ¹ is about 90 after the top dead center.

Point E indicates the opening point of the exhaust valve. The point E ¹ shows the corresponding temperature, which is significantly higher than that of a conventional four-stroke internal combustion engine. Also noticeable is the very slow drop in temperature after point D ^J , which means that the residual mixture in the main combustion chamber 2 burns over during the exhaust stroke of the piston.

The temperature curve shows that a longer period of time to Oxidation of hydrocarbons is more available than it is possible in conventional engines, and that high temperature Exhaust gas is effective for preheating the intake mixture and for oxidizing the still unburned Hydrocarbons can be used in the exhaust pipe.

If the relative sizes of the auxiliary incinerators and the main combustion chamber and the size of the torch nozzle elected once with regard to the auxiliary combustion chamber the following factors determine the size and the air-fuel ratio the mixture cloud.

Weight of those sucked into the auxiliary combustion chamber

air

Weight of air drawn into the main combustion chamber

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22.107.171 ^ 233510

l) i * 6 iufii-Troiontoxf-supply of the mixture sucked into the auxiliary fuel tank - α

The air-fuel verb tr; is dec in the main burners sucked in mixture - α

When R equals the ratio

Weight of the air sucked into the auxiliary combustion chamber Total weight of the air sucked into the two at a time

is assumed, then R =

The size of the mixture cloud is largely determined by the ratio A or R and the air-fuel ratio of the mixture cloud immediately before ignition is mainly determined by α.

At low loads, the ratio H should decrease the HG emission can be made relatively large. At large Load should be the ratio R to optimal regulation. the NO emissions can be made small. In addition, the NO and HO emissions through a suitable choice of the air-fuel ratio the mixture cloud is reduced as much as possible with regard to R under different loads will. The air-fuel ratio of the mixture cloud is mainly determined by α. That is, the larger

α, the greater the air-fuel ratio a

Mixture cloud; the smaller oc_, the smaller the air-fuel ratio. Since a _{m is} much larger than α, the effect of a _m on the air-fuel ratio of the mixture cloud is much weaker than that of α.

When the load is high, the ratio R is made small in order to reduce the NO emissions as much as possible. if

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22,107,171 nc * 233510}

the ratio E is made very small, the air-fuel ratio is said to be be rich for the mixture cloud, so that the plasma spreads into the lean mixture, by acceleration is improved, resulting in large HC emissions been avoided. This is achieved by making α small is made. If the ratio E is made somewhat larger at high load, the flanim will spread excessively accelerated. To reduce NO emissions, it is therefore better to have a lean mixture cloud,

d. H. a large value of cc. In other words, that

Ratio E should be smaller at high loads than at low loads. However, there is a maximum limit for

T?

the ratio - regardless of the change in the ratio E. BeS a special series of tests resulted in the best emission values if, with the recognized test standard, based on a driving speed of 80.46 km / hour (50 miles / hour), the ratio - between 0.0055 and 0.016. At a driving speed of 80.46 kg / hour of the motor vehicle, hereinafter referred to as the standard test condition, exceeds the The peak temperature in the main combustion chamber does not exceed about 1200 ° C.

If you push the above considerations through the fuel flow into the auxiliary combustion chamber, one obtains:

^G fa - ^E ■ £ - ^E · Vrt- £
a a.

G ~ = weight of that supplied to the auxiliary combustion chamber Fuel

Weight of those sucked into the auxiliary combustion chamber

P _ air _:

Total weight of the air sucked into both chambers

G .. = total weight of the air sucked into both chambers α = the air-fuel ratio of the auxiliary combustion chamber supplied mixture

- 25 -

409846/0248

μ - volumetric efficiency

• γ = specific weight of the air (constant) V, = cylinder volume
Since ^ 7 is determined by the load, the following applies:

where E. = Ψ [. γ (this value is given below a

Constant load condition)

At a speed of 80.46 km / hour (standard test condition) the best results are obtained when the fuel flows into the auxiliary combustion chamber pro Unit of the cylinder volume and the value per cycle 5.5 x 10 "to 5.5 χ 10 (grams per cm ^ and per cycle) owns.

In order to reduce the HC emissions, it should be used at low loads the mixture cloud can be made larger than under heavy loads. If the ratio E is sufficiently large is made, the flame spread is good, and reducing of the ITO emissions, the mixture cloud should be relatively lean. Of course, if the mixture is too lean, it will burn not. However, since the ratio R is significantly greater at low loads than at high loads,

R.
the ratio ■ - greater than with a high load.

^a a

If a somewhat smaller ratio R is selected for a low load, the air-fuel ratio should be the mixture cloud can be made small (small α) in order to reduce the

R to support flame spread. For the relationship -

the optimal value was found at low load, and the best results were obtained at idle if that

Ratio - is between 0.013 and 0.030, a

- 26 409846/0248

22.107-171 ^ 233510}

Nevertheless, the power required at idle is different even for hotors with the same cylinder capacity according to the design of the moving parts and the number and type of accessories that are actuated by the engine »That is, the combustion temperature changes at idle for the different engines considerably. Under idle conditions it is therefore sometimes better to make the mixture cloud large even at the expense of a larger ITO emission, or to make the air-fuel ratio of the mixture cloud small (namely - make it large) in order to avoid large HC emissions. ^a If in this way the HC emission is reduced at the expense of the Ή0 emission, it is sometimes appropriate ^{to macnen} - = O »O35 ·

a R

taking this into account, the range for - im

Idle between 0.01J and 0.035. ^a

If the carburetor adjustment is carried out in the manner described above, then
2 and 6 can be selected.

is carried out, a suitable value for oc_ can be between

As long as the total air-fuel ratio is fixed, the ratio is - in a constant relationship to the ratio ^ -. ^a

Changes in the design and the cylinder capacity of the engines change the total air-fuel ratio α +, not very much under the various load conditions. The carburetor should be set in such a way that α ^ when idling comes close to the stoichiometric mixture ratio and is leaner at high load, when monitoring of the NO emissions is necessary, than when idling. For each load can therefore - represented by the expression fa

^G ft

will give. The desired clean combustion can be achieved by opening the auxiliary throttle valve in relation to the opening of the main throttle valve

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22.107.171 - ₃ o-jocmi

adjusted in such a way that under all conditions

cfrin ^ cibö silica agent an optimal value for fa recovered.

^G ft

Me optimal ranges for fa are the following:

^G ft

Idle 0.20-0.55

80.467 ion / hour (standard test

condition) 0.10 - 0.30

Full load 0.06 - 0.18

Compare the graphs shown in Figs the characteristics of conventional four-stroke internal combustion engines with spark ignition with motors according to the invention. Fig. 18 compares the NO ^, HC and CO production of conventional ones Engines with the engines according to the invention. Fig. 19 shows how conventional engines with conventional combustion characteristics have a high peak temperature in the cylinder existing gas, and as according to the invention motors cause a significantly lower peak temperature. It can also be seen that the HC reaction zone for a conventional engine is much shorter in time than that HC reaction zone of motors according to the invention.

In the case of a motor actually built and operated according to the invention as an example, the following dimensions and other data was used and the following temperatures were measured:

Number of cylinders 4

Cylinder diameter 84 mm

Piston stroke 88 mm

Cylinder volume in total 1950 * 7 cm ^

Volume cfer main combustion ^

chamber (V _m ) 62.5 cm /

Volume of auxiliary combustion

chamber (V) 4.2

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Cross-sectional area of the torch nozzle on the

narrow point (if any) 0.503

8.3: 1 compression ratio

Maximum peak temperature under standard test conditions approx. 1200 C

Maximum temperature of the exhaust gases

at full load '900 ° C

Total air-fuel ratio

Full load 18.5

. Air-Ti-pulp-total ratio in Idle 15> 5

Air-to-fuel ratio of the rich

Mixture at idle and at full load (<x _o ) 3.0 air-fuel ratio of the lean

Mixture at full load (a _m ) 20.6

Air-fuel ratio of the lean

Mixture at idle (cc) * 23i3

Physical investigations carried out on automobile engines according to the invention have shown that the NO, HC and CO emissions in the exhaust gases are significantly below the maximum values approved for 1975 by the United States Environmental Protection Agency in accordance with the Clean Air Act in 40 CFR Part 85 which contains the measurement of the exhaust emissions under the following conditions I The engine is started cold, gradually accelerated to a speed of 45 km / hour, held at this speed for 15 to 20 seconds, gradually decelerated to 25 km / hour, held at this speed for 10 to 15 seconds, gradually accelerating to a maximum speed of 60 km / hour, then gradually slowing down to idling and stopping, the entire process lasting 130 seconds. The engine is then run for a distance of 80,467 km before repeating the same test. The maximum values (g / 1.6094 km) for 1975 are:

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22.107.171

HG CO NC)

0.41

5.40 3.00

409846/0248

Claims (1)

22.107.171 3 / ^j0> P at ent an s ρ r ü c he Four-stroke internal combustion engine, in particular one. such according to the German patent application P 22 59 286, with at least one cylinder receiving a piston, characterized in that the or each cylinder has a main combustion chamber partially defined by the piston (2), one equipped with an ignition device (4) and with the main combustion chamber above a flame channel O) related auxiliary verb separation chamber (5), wherein the auxiliary combustion chamber is much smaller than the main combustion chamber and has a thin-walled metal sleeve (29) is limited, in the wall of which an opening representing the flame channel (3) is formed, and means for supplying a relatively lean air-fuel mixture to the main combustion chamber and a device for supplying a relatively rich air-fuel mixture having in the auxiliary combustion chamber, wherein the The main combustion chamber, the auxiliary combustion chamber and the flame channel are arranged in such a way as to one another are and have such dimensions that when the engine is working during each intake stroke and the following compression stroke a massively rich air-fuel mixture is formed in the main combustion chamber near the flame channel, thereby causing that the mixture in the main combustion chamber burns gradually after ignition, in the essentially over the entire working cycle of the piston and with a low peak combustion temperature. 2. Internal combustion engine according to claim 1, characterized in that the sleeve (29) from the surrounding wall (27) a cavity which is used to receive them in the cylinder - 31 409846/0248 22,107,171 ' head serves, has a distance. 3. Internal combustion engine according to claim 2, characterized in that that the sleeve (29) in. essentially cup-shaped and is clamped by a splash (JC)) extending around its edge. 4, internal combustion engine according to one of claims 1 to 3, characterized in that the sleeve has in its V / and a second opening (34) which is a connection between the ignition device (4) and the interior of the sleeve. 5 ·. Internal combustion engine according to claim 4, characterized in that that the ignition device (4) is a spark plug, that the second opening (34) does not coincide with the first Opening (3) is aligned, and that the electrodes (49) of the spark plug are outside the flow path of the air-fuel mixture are arranged in the auxiliary combustion chamber. 6. Internal combustion engine according to one of the preceding claims, characterized in that the main combustion chamber and the head piece of the piston (1) in the Wise designed that the turbulence in the main combustion chamber during the intake and Compression stroke is reduced as much as possible. 7 internal combustion engine according to one of the preceding claims, characterized in that the volume of the auxiliary combustion chamber (5) is between 5% and 12% of the total volume of this chamber and the main combustion chamber (2) when the piston is in the upper Dead center is located, and that the smallest Cross-sectional area of the flame channel (3) between 0.04 2
and 0.16 cm per cubic centimeter of the volume of the auxiliary combustion chamber. - 32 409846/0248 22.107.171 8. Internal combustion engine according to one of the preceding claims, characterized in that the peak temperature of the combustion under certain operating conditions of the engine is not more than 1200 ° G. 9 internal combustion engine according to one of the preceding claims, characterized in that the combustion temperature in the main combustion chamber under certain operating conditions does not drop below about 800 0 over the entire work cycle. 10. Internal combustion engine according to claim 8 or 9i, characterized in that ' that the specific operating conditions have the feature that the inventive Motor vehicle containing an internal combustion engine travels at a speed of 80.46 km / hour. 11. Internal combustion engine according to one of the preceding claims, characterized in that the devices for Feeding a relatively lean mixture into the main combustion chamber and one relatively rich mixture in the auxiliary combustion chamber a corresponding first (14) and second (15) Carburetors included, each of which has a venturi inlet port (37, 38) and a throttle valve (39, 41), the smallest cross-sectional area of the Flame channel (3) is larger than the smallest cross-sectional area of the venturi inlet opening of the carburetor (15) 12. Internal combustion engine according to claim 11, characterized by a control device (40, 42, 44, 45 and 46) which serves to control the opening and closing movements of both Throttle valves at the same time, but in different ways, to control relative extent between the idle and the full load position. - 33 409846/0248 22,207,171 15 internal combustion engine according to one of the preceding claims, characterized by means (18) for a diverting the exhaust gases from the main combustion chamber, this facility being in heat exchange relationship with the device (17) for the supply of the rich mixture is arranged. 14. Working method of a four-stroke combustion engine of the includes at least one piston receiving cylinder, the or each cylinder being a partial the main combustion chamber delimited by the piston, a equipped with an ignition device and connected to the main combustion chamber via a flame channel has standing auxiliary combustion chamber, wherein the auxiliary combustion chamber is significantly smaller than the main combustion chamber and through a thin-walled one Metal sleeve is limited, in the wall of which an opening representing the flame channel is formed, as well as a device for feeding a relatively lean air-fuel mixture into the main combustion chamber and a device for supplying a relatively rich air-fuel mixture in the auxiliary combustion chamber, characterized in that that when the engine is working during each intake stroke and the following compression stroke in the A massively rich air-fuel mixture is formed near the flame channel, which causes when igniting the mixture in the main combustion chamber burns in a gradual manner, essentially over the entire stroke of the piston every now and then with a low peak combustion temperature. 15 · The method according to claim 14, characterized in that in the main combustion skammei * during the intake and Compression stroke reduce the turbulence as much as possible - 34 - 409846/0248 22,107,171 55 " ringert vdrd, to the layered structure of the in the Combustion chamber introduced mixture to favor. 16. The method according to claim 14 or 151, characterized in that that is the ratio of the weight of the fuel supplied to the main combustion chamber during each intake stroke Air to the weight of the air supplied to the auxiliary combustion chamber during each intake stroke is increased as the load on the motor increases. 17 · The method according to any one of claims 14 to 16, characterized in that the ratio of the weight of the during each intake stroke of the fuel supplied to the main combustion chamber to the weight of the during each intake stroke of the auxiliary combustion chamber supplied Fuel increases when the load on the kotor increases. 18. 'The method according to any one of claims 14 to 17 j thereby characterized in that the ratio of the weight of the during each intake stroke of the auxiliary combustion chamber supplied fuel to the total weight of the two combustion chambers during each intake stroke supplied fuel changes for certain operating conditions in the following way: . Idle · 0.20-0.55 Full load 0.06 - 0.18. 19- The method according to any one of claims 14 to 18, characterized characterized in that the volume of the auxiliary combustion chamber between 5% and 12% of the total volume of this chamber and the main combustion chamber, if the Piston is in its top dead center position, and that the smallest cross-sectional area of the p Flame channel between 0.04 and 0.16 cm per cubic - 35 409846/0248 22.107.171 ^^ ** "Centit ^ cfnr" of the volume of the auxiliary broadening margins amounts to. 20. The method according to any one of claims 14 to 19, since you lined up marked that the peak temperature of combustion does not exceed a value of approximately 1200 ° G under certain engine operating conditions. 21. The method according to any one of claims 14 to 20, characterized in that the combustion temperature in the Main combustion chamber under certain operating conditions . conditions of the Kotor during the work cycle drops below about 800 ° C. 22. The method according to claim 20 or 21, characterized in that the specific operating conditions the Have feature that is the inventive Motor vehicle containing the engine is traveling at a speed of 80.46 km / hour. - 36 409846 / Ü248 3> Blank page