DE3545440A1 - METHOD AND DEVICE FOR APPLYING A STRATIFIED CHARGE TO OTTO ENGINES - Google Patents

Abstract

Process for feeding a layered charge into spark ignition engines in which a rich gas mixture is used in the region of the ignition plug (5) and a linear mixture is used elsewhere. The rich mixture is fed at pressure to the ignition plug trough compression slots (16, 18). In one embodiment, at least one strongly accelerated eddy is formed in the middle of the combustion chamber (12) by the type and shape of the latter, as well as by the position of the compression slots. In this way a very low fuel consumption is achieved, with minimal CO, CH and NOx contents. The engine can be operated with a mixture having an overall composition of 1,5 Lambda and above, whereas in the region of the spark plug a good ignition mixture of 0,8 to 1 Lambda is available.

Description

The invention relates to a method and an apparatus for Introduction of a stratified charge in gasoline engines, in which a richer one Layer in the area of the spark plug and in the remaining area or below the lean mixture is there.

Stratified charge in gasoline engines enables operation with very lean mixtures. Consumption figures such as those of the diesel engine, combined with the low CO, CH and NO x proportions in the exhaust gas, are to be achieved.
The real problem with this stratified charge is that the ignition process takes place perfectly, although there is mainly a mixture larger than lambda 1.3 in the cylinder. The more lean the mixture, the lower the pollutant content.

The object of the invention is to provide a method for the ignition of this lean Mixture to provide that one with a relatively very lean mixture still achieved perfect combustion.

The solution to the problem according to the invention is that the fatter Mixture is supplied under pressure to the spark plug.

This process takes a completely new path. So far the lean mixture was only stored by the intake pressure reached. You needed a lot of fat mixture to achieve a perfect ignition process.

General protection is claimed in the present invention for that a richer mixture is fed under pressure to a spark plug regardless of the measures taken on the piston crown and this pressure is generated on the associated cylinder wall, the  is, of course, above the compression pressure that is present anyway.

The essence of the present invention is therefore that the fatter mixture targeted, like with a jet-like accelerated jet, the spark plug feeds and the lean mixture stored in the combustion chamber initially not in contact with this targeted jet of the richer mixture brings, but only initiates the ignition with the richer mixture and only with the resulting ignition jet a mixture and ignition achieved with the lean mixture.

In a first embodiment of the present invention it is provided that the richer mixture over at least one nip targeted to the spark plug, whereby it is essential that the fatter mixture accelerated like a nozzle over this pinch gap flows into the combustion chamber and on the opposite side the spark plug located in the combustion chamber hits while the lean Mixture via other valves, outside the pinch gap into the combustion chamber is introduced. This ensures that the spark plug first only the fatter mixture is hit, which is an extraordinary ensures good and safe ignition of this mixture. Which then the resulting ignition beam is used to ignite that in the combustion chamber stored lean mixture used, which due to the initial ignition then well ignited by the ignition jet and practically completely burns.

Another embodiment of the present invention provides that further improve the directivity of the richer mixture towards the spark plug is achieved by the fact that after the first embodiment already existing nip still in Direction towards the spark plug is extended by the fact that it extends so far extends into the existing combustion chamber that he in the space between the valves arranged above in the cylinder head wall protrudes. As a result, the pinch length in the direction of the spark plug becomes essential lengthened and thus a further acceleration of the richer mixture and an improvement in the directional effect on the spark plug is achieved.  

This exemplary embodiment therefore assumes that a relatively long, extending almost over the entire width of the combustion chamber There is a pinch gap in which the rich mixture from the inlet valve Accelerated towards the spark plug through the combustion chamber and aimed at the spark plug.

This longer pinch gap is now followed by a middle pinch gap, which extends as far as possible into the combustion chamber, whereby this maximum possible length is limited by the fact that it is otherwise the valves arranged above in the cylinder head wall would.

This downstream, middle pinch gap takes care of that Mixture that already accelerates from the first nip was and accelerates it further and thereby achieves an extraordinary favorable acceleration of the exiting from the mouth of this pinch gap Mixture towards the spark plug.

You can now change the direction of the middle nip from the direction of the longer, outer pinch gap.

A first embodiment accordingly provides that the longer squeezing gaps entering the combustion chamber about in the Middle of the combustion chamber (based on the height of the combustion chamber) and produces essentially no rotation during the middle nip is directed towards the upper cylinder head wall and in connection with deflection means in the combustion chamber then a strongly rotating one generated medium flow roller, which acts on the spark plug.

In the other modification of this principle, it is provided that the outer Nip has the same inclination as the middle nip and that both pinch slots obliquely against the upper cylinder head wall are directed.

The flow rollers generated by the longer nip then rotate as well as the middle flow roller, which is from the middle one Pinch gap is generated.  

Now the rich mixture of the spark plug is fed under pressure and at the same time a rotation in the combustion chamber is reached, then an guaranteed much better and more extensive ignition process.  

In a constructive embodiment of a device according to the Invention, it is preferred that the combustion chamber on one side of a formed in the piston crown, trough-shaped recess and associated rounded surfaces of the cylinder head is that at the other side of the combustion chamber, a pinch gap is formed, on the one hand from a surface of the piston crown and on the other hand from an associated one Area of the cylinder head is formed that the first nip opens into the combustion chamber and there depending on the direction this nip is either just a laminar, non-rotating Pinch flow or - if it is against the upper one Cylinder head wall directed nip acts - a first rotating Flow roller generated; being approximately in the middle of the first nip and in extension of the first nip the second nip formed between the piston crown and the associated surface of the cylinder head is and generates a second rotating flow roller, which on the Spark plug is directed.

Seen across the width of the combustion chamber is a first pinch column arranged, which ensures that the first inlet valve, which supplies fatter mixture, is introduced into the combustion chamber and a first rotating flow roller is generated there. In the middle of this first inlet valve is - also approximately in the center of the piston crown - a further pinch gap is arranged, which is the first pinch gap extended, this nip a second rotating flow roller generated that is aimed exactly at the spark plug.

One can look at the embodiment in which the first pinch column is directed against the cylinder head wall - seen across the width - About imagine that two slower rotating flow rollers on the outside are formed, which are generated by the first, wide nip were. These two outer flow rollers are through in the middle a faster rotating, central flow roller separated from each other. A faster rotation of this central flow roller therefore occurs because the central pinch gap is an extension of the wider one Pinch gap is arranged and therefore its pinch flow already already with a high initial speed in the mouth of this second nip occurs and is strongly accelerated again by this so that it becomes the central  faster rotating flow roller that comes exactly on the spark plug is directed. As a result, the spark plug is initially a relative rich mixture presented, resulting in an immediate and safe ignition leads in the form of an ignition beam, which is introduced into the combustion chamber in this way is that it is approximately parallel to the rotating flow rollers enters the combustion chamber and the rotation effect reinforced. The central, rapidly rotating flow roller, which now contains the ignition beam, quickly settles into the side outside rotating flow rollers, which are ignited extremely quickly and safely by the spreading ignition jet, so that overall safe ignition of the rotating in the combustion chamber Mixture is guaranteed.

It has been found that the combustion process can now be carried out perfectly with much lower NO x and CO contents, because the combustion is very intensive due to the richer mixture supplied under pressure.

Of course, all other options are also under pressure to supply a richer mixture to the spark plug, included in the invention. In a preferred embodiment, this usage appears a pinch column as the simplest solution.

Versions with a side chamber for the fat mixture did not bring the desired Success. As a result of the jagged combustion chambers, the CH high and consumption did not meet expectations.

Stratified charges in a combustion chamber with specially directed direct injection - e.g. B. Proco engine from Ford - brought in constantly changing Speed and load range for car engines despite a very long development time unsatisfactory results. Also are these systems are complex and expensive.

Further features of the invention are the subject of the remaining subclaims.  

The subject matter of the present invention is not only apparent from the subject of the individual claims, but also from the Combination of the individual claims.

All information and features disclosed in the documents, especially the spatial training shown in the drawings are considered claimed according to the invention insofar as they are used individually or in combination are new compared to the prior art.

In the following, the invention will be explained using only one embodiment illustrative drawings explained in more detail. Here go out the drawings and their description further essential to the invention Features and advantages of the invention.

Show it:

Fig. 1: plan view of the piston crown of a piston with a combustion chamber according to the invention and in dashed lines the position above the cylinder head valves and intake pipes disposed in a first embodiment, with a first, long nip,

Fig. 2: section along the line A - B in Fig. 1

Fig. 3: plan view of the piston crown of a piston with a combustion chamber according to the invention with in dashed lines the position above the cylinder head arranged valves and intake pipes, with a longer nip and a downstream middle nip,

Fig. 4: section along the line A - B in Fig. 3

FIG. 5 shows curves of the valve opening times of the three valves,

Fig. 6: Section along the line VI-VI in Fig. 2 through the combustion chamber.

A piston 1 runs in a cylinder 11 , which is shown in the top dead center position in the illustration according to FIGS. 2 and 4.

The cylinder 11 is covered at the top by a cylinder head 10 , in which, as shown in FIG. 1, three valves 2, 3, 4 are arranged, the valves 2, 3 being designed as intake valves and valve 4 as an exhaust valve. The inlet valve 3 receives its mixture via the intake pipe 7 , while the other inlet valve 2 receives its mixture via a further intake pipe 6 .

The outlet of the outlet valve 4 is not shown for the sake of clarity.

The combustion chamber 12 shown in FIGS. 1 and 4 is formed between the piston crown 27 of the piston 1 and the associated surfaces of the cylinder head 10 . The same parts are designated by the same reference numerals.

In the piston head 27 , a trough-like depression 28 is machined on one side, which, together with the associated, overlying surfaces of the cylinder head, looks roughly profiled, as shown in FIG. 2.

Corresponding deflection bends 26 are incorporated in the trough-like recess 28 and the same deflection bends are also located in the parts of the cylinder head located above.

Can be in Fig. 1 and 2 is now illustrated a first embodiment, as a richer mixture under pressure of the combustion chamber in the intake valve 2 disposed opposite the richer mixture spark plug 5 is fed.

The piston crown 27 here forms a pinch gap 16 which extends approximately over the width of the combustion chamber 12 . The pinch gap 16 is formed here by an essentially straight surface of the piston head 27 in connection with an opposite, straight surface in the cylinder head 10 . In the area of this pinch gap 16 , the inlet valve 2 is arranged for the inlet of the richer mixture.

In the position shown in FIG. 2, the inlet valve 2 has already closed again and the rich mixture was shot through the pinch 16 in the form of a pinch flow 29 almost straight into the combustion chamber 12 , where this pinch flow 29 hits the spark plug 5 and then the Ignition is initiated. The ignition jet 22 resulting in the rich mixture (see FIG. 4) then serves to promote the rotation in this area and to completely ignite the lean mixture stored in the combustion chamber.

It is within the scope of the exemplary embodiment described here that the pinch gap 16 is also arranged obliquely and, in the form of a wedge combustion chamber, directs its pinch column flow 19 precisely to the spark plug 5 arranged opposite.

The exemplary embodiment in FIGS. 3 and 4 differs from the first-mentioned exemplary embodiment in FIGS. 1 and 2 in that a further, middle pinch gap 18 is provided behind the first pinch gap 16 .

On the left side in Fig. 4, the first nip 16 is in the piston head 27 again formed, which consists firstly of a straight surface of the piston crown 27, which cooperates with an associated flat surface of the overlying wall of the cylinder head 10. The nip 16 again extends essentially according to FIG. 3 over the entire width of the combustion chamber, the nip flow 29 emerging from this nip being directed straight into the combustion chamber 12 in a first exemplary embodiment and then not producing any external, rotating flow rollers 39 . A middle, rotating flow roller 38 is then generated only through the middle nip. In a second embodiment, however, the nip 16 is also slanted against the underside of the valves 3, directed 4 and the flowing out of it Quetschspaltenströmung 29 is then the recess 28 is deflected to the associated arcuate surface of the wall of the cylinder head 10 and the associated deflection curve 26 in the piston crown , so that there is a flow roller 39 deflected in the direction of arrow 21 (see FIG. 6) of a mixture 23 .

As shown in FIGS. 4 and 6, the flow roller 39 is also deflected at the bottom of the depression 28 in the direction of the arrow 20 , so that a flow roller 39 extends across the entire width of the combustion chamber 12 through the wide nip 16 .

As shown in FIGS. 3 and 6, the nip width 16 is extended in the center by a further nip 19, this nip wobie into the gap between the arranged above the cylinder head 10 valves 3, 4 extends. The nip 19 is thus an extension of the wider nip 16 arranged behind it and receives its mixture from the latter nip 16 at a relatively high initial speed. It is here to a further acceleration in the direction of arrow 17 (see. Fig. 4) and the Quetschspaltenströmung generated from this nip 19, center 18 (see FIG. FIGS. 4 and Fig. 6) occurs at a higher speed in the combustion chamber 12 a than the nip flow 29 generated by the other nip 16 . In this way, a faster rotating flow roller 38 is thus generated approximately in the middle of the combustion chamber, which is directed precisely at the spark plug 5 arranged opposite in the cylinder head 10 . Characterized in that the middle pinch gap 19 extends far into the combustion chamber 12 , the chamber volume of the combustion chamber at this point and thus also the distance from the mouth of the pinch gap 19 to the spark plug 5 is advantageously reduced, which contributes to a further acceleration of the pinch gap flow 18 .

At the beginning of the intake stroke, the inlet valve 3 first opens, through which pure combustion air may be drawn in with the addition of exhaust gas or a very lean mixture. Only later does the inlet valve 2 open, through which richer mixture is drawn in via a carburetor or injection.

The engine receives pure combustion air or a very lean mixture in the lower part of the combustion chamber and later a mixture of combustion air or lean mixture with a richer mixture. In the upper part of the cylinder filling, the cylinder 11 receives only a richer mixture via the opened inlet valve 2 , while the inlet valve 3 is already closed. Fatter mixture over the first cross section 16 is then initially pre-accelerated via the opened inlet valve 2 in order to then obtain its high final acceleration through the second pinch gap 19 and then to enter the combustion chamber 12 in the form of a highly accelerated pinch flow 18 and to hit the opposite spark plug 5 .

After the central pinch gap 19 is in the extension of the approximately centrally arranged inlet valve 2 , the richer mixture is thus greatly accelerated by the two pinch gaps 16, 19 arranged one behind the other and, as stated, reaches the combustion chamber 12 in the form of a strongly accelerated pinch gap flow 18 , which this highly accelerated nip flow 18 safely ignites. In a preferred embodiment, the ignition jet 22 generated in this way is introduced approximately parallel to the flow rollers 38, 39 rotating in the combustion chamber 12 , so that there is a further strong acceleration of the flow rollers 38, 39 and at the same time the ignition jet via the flow roller rotating rapidly in the middle 38 is carried into the laterally flowing nip streams 29 or into the laterally rotating flow rollers 39 and thereby also leads to a reliable ignition of these nip streams 29 or flow rollers 39 .

It is preferred here if the spark plug 5 is arranged in an antechamber 24 set back from the combustion chamber 12 in the cylinder head 10 and the antechamber 24 has a chamfered edge 25 such that the ignition jet 22 - in the manner described above - parallel to the flow rollers 38 , 39 enters the combustion chamber 12 .

According to the embodiment of FIG. 4, the average squish 19 is formed as Quetschnase 30, the approximately wedge-shaped extends as shown in FIG. 3 and FIG. 6 in plan view, in the space between the overlying valves 3, 4. The pinch nose 30 has a front, approximately flat, end face 31 , which is adjoined by wedge-shaped rear faces 32 . It is important here that the middle pinch gap 19 is extended as far as possible in the direction of the spark plug 5 in order to direct a straight and directed short flow of the rich mixture to the spark plug 5 .

In order to simplify the formation of a leaner and richer mixture even more, the total mixture is generated via channels 6, 7 to valves 2, 3 only by a carburetor or an injection device and by adding combustion air upstream of valve 3 at point 9 this mixture became emaciated. This air additive can be inserted in an intermediate piece 8 between the intake manifold and the cylinder head. The control takes place via a throttle valve or other valve, which is connected with the control of the opening of the carburetor throttle valve. When the engine is idling, the throttle valve for the additional air is closed. Instead of pure combustion air, exhaust gas or a mixture of exhaust gas and combustion air can also be supplied.

Due to the not exactly separated stratified charge, in which the grease mixture and combustion air in the zone of contact during the intake and compression process undergo a transition mixing, a perfect burning of all fuel particles is guaranteed. With an excess of air that would not be ignitable without stratified charge, this results in very low consumption with very low CO, CH and NO x fractions. It can be run with a total mixture composition of lambda 1.5 and more, with a readily ignitable mixture of lambda 0.8-1 being located in the area of the spark plug.

The low consumption and the very low values of all toxic components in the Exhaust gases are only achieved when the combustion is in an un-jagged Combustion chamber takes place, which is the case with this invention.

The following changes are made to the known engine:

1. Both valves 2, 3 have separate intake pipes 6, 7 , one intake pipe 6 being supplied with a richer mixture and the other intake pipe 7 being supplied with a lean mixture or pure combustion air.

2. The opening times of both valves are not the same. The valve 3 is controlled as usual with normal opening and closing times, approximately 40 ° before top dead center to 50 ° after bottom dead center, or rather closes according to curve 14 . The control curve from the outlet valve 4 is indicated by curve 13 .

The inlet valve 2 opens later by approximately 20-40 ° and closes later than the other inlet valve 3 , see curve 15 .

All of the previously described exemplary embodiments are characterized by that one half of the combustion chamber in a trough-shaped recess in the piston crown and the other half of the combustion chamber in the cylinder head located. In the context of the present invention, moreover, is separate Protection claims that the combustion chamber is essentially located in the upper cylinder head. That means the tub-shaped There is no recess in the piston crown and the piston crown is in it Area formed flat and forms with the right pinch column in the essentially a continuous level.

• DRAWING LEGEND 1 piston
  2 inlet valve
  3 inlet valve
  4 outlet valve
  5 spark plug
  6 suction pipe
  7 suction pipe
  8 intermediate piece
  9 digit
  10 cylinder head
  11 cylinders
  12 combustion chamber
  13 curve (control curve outlet 4 )
  14 curve (control curve inlet 3 )
  15 curve (control curve inlet 2 )
  16 pinch gap (outside)
  17 arrow direction
  18 pinch flow (middle)
  19 pinch gap (middle)
  20 arrow direction
  21 arrow direction
  22 ignition beam
  23 Mix
  24 vestibule (spark plug 5 )
  25 edge (vestibule 24 )
  26 deflection bend
  27 piston crown
  28 deepening
  29 nip flow (outside)
  30 pinch nose
  31 end face (pinch nose 30 )
  32 side surface (pinch nose 30 )
  38 flow roller (middle)
  39 flow roller (outside)

Claims (18)

1. A method for introducing a stratified charge in gasoline engines in which a richer layer in the area of the spark plug and in the rest of the area or below is the lean mixture, characterized in that the richer mixture is supplied to the spark plug ( 5 ) under pressure. 2. The method according to claim 2, characterized in that the supply of the richer mixture to the spark plug ( 5 ) takes place by rotation of this mixture in the combustion chamber ( 12 ). 3. The method according to claim 1 and 2, characterized in that the richer mixture is supplied under pressure to the spark plug ( 5 ) and together with the ignition jet ( 22 ) a rotation of the mixture in the combustion chamber ( 12 ) is generated. 4. Apparatus for performing the method according to claim 1, characterized in that the inlet valve ( 2 ) for the richer mixture is located opposite the spark plug ( 5 ). 5. Apparatus for carrying out the method according to claim 1, characterized in that the combustion chamber ( 12 ) on one side of a in the piston crown ( 27 ) formed, trough-shaped recess ( 28 ) and associated rounded surfaces of the cylinder head ( 10 ), that the other side of the combustion chamber ( 12 ) a pinch gap ( 16 ) is formed, which is formed on the one hand from a surface of the piston head ( 27 ) and on the other hand from an assigned surface of the cylinder head ( 10 ) that the first pinch gap ( 16 ) into the combustion chamber ( 12 ) opens and there creates a first rotating flow roller ( 39 ) that approximately in the middle of the first nip ( 16 ) and in extension of the first nip ( 16 ) the second nip ( 19 ) between the piston crown ( 27 ) and the associated surface of the cylinder head ( 10 ) is formed and generates a second rotating flow roller ( 38 ) which is directed towards the spark plug ( 5 ). 6. The device according to claim 5, characterized in that the second pinch gap ( 19 ) consists of a in the plan view approximately wedge-shaped pinch nose ( 30 ) which is arranged in the piston crown ( 27 ), and which so far in the trough-shaped recess ( 28 ) extends in the piston crown ( 27 ) in such a way that it protrudes into the space defined by the two valves ( 3, 4 ) arranged next to one another at a distance in the cylinder head ( 10 ). 7. The device according to claim 5, characterized in that the nip flow ( 18 ) generated by the central pinch gaps ( 19 ) is directed obliquely against the underside of the cylinder head ( 10 ). 8. The device according to claim 5, characterized in that the spark plug ( 5 ) is directed at such an angle to the rotating in the combustion chamber ( 12 ) rotating flow rollers ( 38, 39 ) that the ignition jet ( 22 ) approximately parallel to the flow roller ( 38th , 39 ) enters the combustion chamber ( 12 ). 9. The device according to claim 8, characterized in that the spark plug ( 5 ) in a from the combustion chamber ( 12 ) recessed vestibule ( 24 ) is arranged in the cylinder head ( 10 ), and in that the vestibule ( 24 ) is oriented at an angle, that the ignition jet ( 22 ) emerging from the antechamber ( 24 ) enters the combustion chamber ( 12 ) approximately parallel to the flow roller ( 38, 39 ). 10. The device according to claim 5, characterized in that two inlet valves ( 2 ) and ( 3 ) are present, pure combustion air or lean mixture being sucked in via a first inlet valve ( 3 ) and richer mixture being sucked in via the second inlet valve ( 2 ). 11. A method for introducing a stratified charge in gasoline engines in which a richer and lean layer or pure combustion air is in the combustion chamber, characterized in that pure combustion air or lean mixture is sucked in and stored in the cylinder ( 11 ) during suction at the bottom of the piston surface , then a mixture of combustion air or lean mixture and fat mixture is introduced into the top of the cylinder head by the intake process and the richer mixture is stored. 12. The method according to claim 1, characterized in that a layered stratification is carried out with time separation of the start of intake of combustion air or lean mixture and richer mixture by suction via the two inlet valves ( 2 ) and ( 3 ), wherein an inlet valve ( 2 ) pure combustion air or lean mixture and a richer mixture is sucked in via the other inlet valve ( 2 ). 13. The method according to claim 1, characterized in that the two inlet valves ( 2 ) and ( 3 ) have separate intake pipes ( 6 and 7 ). 14. The device for carrying out the method according to claim 1, characterized in that for both inlet valves ( 2 and 3 ) of a carburetor or other mixture images, the mixture of air and fuel is formed, but before the inlet valve ( 3 ) additional air or exhaust gas or both is fed. 15. The method according to claim 1, characterized characterized in that the supply of air and / or exhaust gas via a throttle, which is in connection with the carburetor control is made and closed when the engine is idling is. 16. The method according to claim 1 and 15, characterized in that the supply of air and / or exhaust gas via an intermediate piece ( 8 ). 17. The apparatus for performing the method according to claim 1, characterized in that the one inlet valve ( 3 ) for combustion air or lean mixture, as is known, is controlled with the normal opening times, but the other inlet valve ( 2 ) opens later and at the same crank angle or an inlet valve ( 3 ) closes somewhat later than that. 18. The apparatus according to claim 1, characterized in that the one inlet valve ( 3 ) closes rather than usual and rather than the other inlet valve ( 2 ).