JPS6256324B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine and a method of operating the same.

In recent years, modern internal combustion engines have come under increasing demands to meet the environmental and economic considerations of modern society. Although some improvements have been made, the combined objectives of improved fuel consumption and lower emissions form a complex problem because the many factors involved are mostly Paradoxically, the methods used to reduce emissions generally increase the engine's fuel consumption, which is totally unacceptable in view of the urgent need to conserve and use our energy resources wisely. This is because they have a tendency.

Any form of liquid or gaseous fuel releases a certain amount of heat for a given weight when completely combusted. Today's well-developed engines have combustion efficiencies that leave little room for improvement in indicated fuel efficiency. However, a considerable improvement is that after the thermal energy of the fuel is released early during expansion with proper consideration of the mechanical aspects of the conversion, it always has a large expansion ratio regardless of the engine load, and thus , by ensuring that a large portion of the expansion energy can be converted into usable rotational torque. This method also uses a lean air-fuel ratio, as it stimulates complete combustion, as well as improving thermal efficiency when the fuel ratio is reduced, as lower flame temperatures reduce direct heat losses. This lean operation is also important in achieving a reduction in undesirable exhaust emissions.

In conventional gasoline engines operated on a normal oil cycle, these requirements mentioned above are not met. This is because the engine relies on combustion under all load conditions at an air-fuel ratio that is easily ignitable with the use of a spark plug. If the ratio of air to fuel is close to that of a chemically correct mixture, the air-fuel mixture will only be ignited by a spark, so a device that ensures that this mixture ratio is maintained regardless of engine load must be provided. To achieve this, the amounts of both air and fuel must be adjusted according to the desired engine load with the use of throttles.

Several disadvantages arise when the amount of air drawn by the engine is limited. First, automobile engines run under partial load (light load) for most of their operating time.
Since the throttle valve is throttled at part load, an efficient expansion ratio cannot be used. In a spark ignition engine, the output greatly increases depending on the degree of compression ratio, so the loss due to not being able to use an efficient expansion ratio is large. Second, when the load is light, the throttle valve is throttled, so the engine acts as a vacuum pump, which applies the force or load required for suction. Third
The fuel-air mixture is always close to the stoichiometric air-fuel ratio and burns at almost the highest temperature, resulting in reduced direct heat losses, an advantage gained when burning at lower temperatures. I can't. Thus, direct heat losses are considerable, while efficiency is further reduced by specific heat effects and dissociation of combustion products. In the normal way spark ignition engines operate, operating conditions in which sufficient air is supplied immediately after fuel is consumed are rare, and combustion of the air-fuel mixture is delayed during part-load conditions in normal operation. , it is almost never completely baked. Therefore, some of the carbon components of the fuel are emitted as carbon monoxide.

Given the diesel engine and the way it is used, why is the thermal efficiency of the engine higher than that of a gasoline engine? It is easy to understand why it costs about 50% less when used in automobiles. Diesels achieve this significant improvement primarily by eliminating the need for throttling. The load is controlled simply by increasing or decreasing fuel consumption. This fuel burns quickly and completely under light loads, and the heat thus created constantly expands with a large and efficient expansion ratio. Also, it is
It is possible to have all the benefits of lower cycle temperatures, the efficiency of which decreases only slightly when the engine load is reduced, while the exhaust products contain little, if any, carbon monoxide. Contains at all times.

Based on these factors, diesel engines offer a better chance of meeting current requirements for lower emissions and fuel consumption than any other current type of engine. however,
These advantages mean that the diesel engine can be configured to meet the stringent requirements of automotive use.
Much of that is sacrificed when we have to adapt to the performance standards set by gasoline engines that we are accustomed to and expect from our vehicles.

The main drawback of diesel engines lies in the high working pressures involved to make the cycle practical. The engine is subject to pressure loads that cannot be exploited without great attention to the materials used in its construction, tolerances, and strength, and generally reduces the cost of manufacturing a gasoline engine for a given power output. It costs twice as much. Even with the best selection of alloys, engine components weigh more and require more bearing area. Therefore, when vehicle engine speeds are approximated, the additional friction and dynamic forces significantly increase mechanical losses, and as high-speed, low-load engine operation is the norm in vehicle use, its thermal Most of the cost savings potential is lost.

Also, the high peak pressures that occur in diesel engines form shock waves that are transmitted through the engine castings, which generate noise that must be eliminated and torsional vibrations that are difficult to control;
Therefore, the power flow is not as smooth as in a comparable gasoline engine. To approach the speeds of gasoline engines, diesel engines utilize some form of turbulent swirl chamber to increase the air velocity to a level where mixing and combustion of the fuel can be completed in the short time available. Must be. this is,
Although it works well and relatively high engine speeds are obtained, its use further reduces the diesel fuel consumption potential, air disturbance takes place during the compression process, and this compression is caused by the injection The fuel must reach a high enough temperature to immediately ignite. When air is forced into the vortex chamber, it loses most of its heat of compression, so a very high compression ratio must be used to compensate for this loss. This procedure correspondingly further increases the pressure of the cycle, and this higher level of compression also increases the density of the working fluid during combustion, since the density of the gas is a major factor in heat exchange, Direct heat loss presents a problem.

Combustion that is forced to use such high compression to ensure combustion is unfortunately not accompanied by such a corresponding increase in efficiency as would be expected. As the compression level is increased, a point is reached where further increases are not worth it from a practical standpoint. Efficiency gains up to about 12:1 are very valuable. After this, they taper off rapidly and are impractical to obtain using normal engine methods. High-speed automotive diesels are forced to use very high levels of compression only to obtain heat for ignition, a level that is about twice the practical ideal of about 12:1. It requires that.

It is an object of the present invention that these relatively small construction and changes to the combustion method result in impractical compression levels to obtain ignition and a correspondingly high The objective is to show how the performance of any suitable engine can be manipulated to create useful engine characteristics of a diesel engine without depending on the cycle pressure. In this manner, split stage combustion provides a solution that eliminates the undesirable aspects of diesel and engine cycles while fully utilizing the useful features of each cycle.

According to the present invention, a cylinder head, a cylinder, a piston that is reciprocated within the cylinder to periodically change the volume of a space between the cylinder head and the cylinder head, and a main combustion engine that continuously communicates with the space. a chamber, an inlet device for periodically introducing an air-fuel component of an ignitable working fluid into the space, a sub-combustion chamber having a smaller volume than the main combustion chamber, and a passage between the main and sub-combustion chambers. wherein the secondary combustion chamber is in communication with the main combustion chamber only through the passage, and wherein no air enters the secondary combustion chamber without passing through the passage. an internal combustion engine, wherein the inlet device is adapted to introduce a fuel component of a working fluid into both the main and auxiliary combustion chambers, the inlet device including the main through the auxiliary combustion chamber; An internal combustion engine is provided, characterized in that it is provided with a valving system that operates periodically to control communication between the secondary combustion chambers.

Further, according to the present invention, at least an air component of the working fluid is introduced into the space to generate the air flow from the space to the main and auxiliary combustion chambers, and the piston is moved toward the cylinder head. compressing at least the air component in the space and the main and auxiliary combustion chambers by moving, and supplying the fuel component of the working fluid into each of the main and auxiliary combustion chambers to compress the air component of the working fluid. A method of operating an internal combustion engine in which the working fluid in the secondary combustion chamber is ignited,
cyclically controlling the fluid between the main and auxiliary combustion chambers by a valve arrangement, in which case the fluid between the main and auxiliary combustion chambers is controlled by the valve arrangement before the compression of at least the air component in the space and in the main combustion chamber is completed; closing the passageway, thereby compressing at least the air component in the secondary combustion chamber to a lower degree than the air component in the space and the main combustion chamber, and igniting the working fluid in the secondary combustion chamber; The passage is kept closed by the valve arrangement during the period of time, and when the pressure in the sub-combustion chamber increases to a predetermined level as a result of ignition, the passage is opened and the working fluid in the sub-combustion chamber is discharged. While still incandescent, the passageway is kept open, causing a sudden discharge of the ignited working fluid through the open valve arrangement and passageway into the main combustion chamber, and the secondary combustion chamber. Igniting the working fluid in the main combustion chamber by contacting it with incandescent working fluid from the combustion chamber, thereby increasing the pressure in the main combustion chamber and the space to cause the piston to move. A method of operating an internal combustion engine is provided.

The invention will be described below with reference to the accompanying drawings.

The illustrated engine is a partially modified conventional internal combustion engine. The engine consists of an almost conventional cylinder block 1 with several identical cylinders.
Only one of the cylinders, designated 12, is shown with its reciprocating piston 14. Piston 14 has a generally flat top. The stroke of the engine is arranged so that there is only a small gap at top dead center between the underside of the engine's cylinder head 16 and the piston.

The cylinder head 16 is equipped with a conventional valve transmission having intake and exhaust valves 18 and 20 for controlling intake and exhaust air to the engine through an exhaust passage 22 and an intake passage 23.

The valves 18, 20 are actuated by an overhead camshaft 24;
The camshaft 24 has a projection acting against a cap 26 on the upper end of the valve, and the valves 18, 20 are springed into the closed position by a spring 28 between a collector 30 on the upper end thereof and the head 16. Forced.

The timing of action of valves 18, 20 is normal for a four-stroke engine.

The surface of the head 16 closing the cylinder 12 is generally flat except for a slightly concave portion 32 (FIG. 2). This part has three protrusions, one extending around the exhaust valve opening, one surrounding the intake valve opening, and a third extending around the head 16.
leading to an inclined passageway 34. The passage 34 leads to the main chamber or vortex chamber 36 of the head 16. The chamber 36 is generally cylindrical with an axis transverse to the axial direction of the cylinder 12, but the outer peripheral surface has a slight helical shape.

Another passageway 38 extends through the chamber 36 within the head 16.
and extends downwardly from another subchamber 40 within the head.
lead to. Chamber 40 likewise has a generally cylindrical shape and its axis is transverse to the axis of cylinder 12 .

Communication between chambers 36, 40 along passageway 38 is controlled by a reciprocating valve 42. valve 42
has an axis parallel to the length of the cylinder 12, and its lower end 42a is received within a cylindrical valve sleeve 46 which is received in the bore 17 in the underside of the head 16. Sleeve 46 is positioned to extend across passageway 38 and has opposed side openings 38 providing communication between passageway 38 and the interior of the valve sleeve.
a, 38b. The valve sleeve is held within the head 16 by a finned cylindrical valve housing 44 at its upper end, with the housing 44 extending over a bore 54 of the head 16 so as to abut the upper end of the valve sleeve to hold the valve sleeve in place. The lower end of the umbilicus (concentric to bore 17) is screwed. A crushable Teflon seal ring 52 is attached to the housing 4.
4 and a lateral lower surface of the threaded bore 54 into which the housing fits.

To precisely position the sleeve with openings 38a, 38b aligned with passageway 38, spacer 56 is located within bore 17 between the upper surface of cylinder block 10 and the lower lateral surface of sleeve 46. Thus, when the housing 44 is screwed into the bore 17, the sleeve 46 is firmly held and aligned between the spacer 56 and the housing 44. The housing 44 then passes through the liquid cooling cavity 48 of the head 16 and upwardly through the upper wall portion 16a of the head that bounds the cavity 48. The upper end of the housing 44 is sealed by an o-ring 50 where it passes through the upper wall portion 16a.

The valve 42 extends from its lower end 42a to a sleeve 46.
and extends upwardly within the internal bore 44 of the housing 44.
a, seal pack 44b and insert 44
c and protrudes from the head 16. Insert 44c is in the form of a threaded annular member that is screwed into an enlarged bore 45 at the upper end of housing 44, and pack 44b is at the lower end of bore 45 and held in place by insert 44c. valve 4
2 has a conventional collet 58 at its upper end forming an outwardly projecting flange and a helical valve spring 60.
is located between the flange and wall portion 16a,
The valve is constantly biased upward so that the lower portion 42a is located above the openings 38a, 38b to maintain the passageway 38 open.

The valve 42 is operated via a rocker arm 62 which is pivotally mounted on a shaft 64 extending parallel to the shaft 24. The rocker arm 62 is connected to the camshaft 24
a first portion 62a that comes into contact with the cam protrusion 24a;
The second portion 62b has a downwardly extending tappet 68 threaded into the threaded opening thereof and positioned against the upper end of the valve 42.

The lower end 42a of the valve 42 is in a tight sliding fit within the sleeve 46 and the upper end 42c is connected to the housing 44.
There is a tight sliding fit inside. Between portions 42a, 42c there is a reduced portion 44b having a cross-section significantly smaller than the bore of the sleeve. valve 42
The movement is such that the valve moves between the upper limit shown and the lower limit (not shown). At the upper limit, portion 42a opens into opening 38 such that passageway 38 opens.
a, above 38b. At the lower limit, part 42a
is below the openings 38a, 38b such that a passageway is likewise open and gas can pass around the valve portion 42b and between the openings 38a, 38b. In a position between these two limits, the portion 42a has openings 38a, 3
8b and the passage 38 are closed. This blockage occurs twice per revolution of the camshaft 24, and therefore twice during each drive cycle. As explained below,
Only one of the blockages, which occurs during upward movement of the valve from the lower limit of valve movement, is important for the basic operation of the engine. This blockage is timed to occur on the engine's compression stroke. However, other occlusions serve secondary functions, as also explained below.

The chamber 40 includes a fuel injector 70 and a spark plug 72. Chamber 36 includes only fuel injector 74. As clearly shown in FIG.
The coolant fluid within is confined within the interior wall 16b of the cylinder head 16 so that it can freely circulate therearound.

Next, the operation of the engine will be generally explained. The engine is operated in a conventional manner in a four-stroke cycle, as described above, except that only air is drawn into the engine during the intake phase. This occurs as valve 18 opens and piston 14 moves down within cylinder 12. During the subsequent upward movement of the piston, the air is compressed, valves 18, 20 are all closed, and valve 42 is opened as the piston moves from bottom dead center. Also,
Injector 70 acts to inject fuel into chamber 40 immediately prior to or in the early stages of compression. Therefore, the air/fuel mixture is compressed within the chamber 40. Although the fuel injected into chamber 40 does not enter chamber 36 to any significant degree, compression of air occurs within chamber 36 . When the compression propagating before reaching top dead center is suitable for ignition combustion, the lower part 42a of the valve 42 is connected to the ports 38, 38.
b is closed by the action of the camshaft 24 via the rocker arm 62 so as to cause its upward movement to close. Compression then continues no further within chamber 40, but continues within chamber 36 until piston 14 reaches top dead center. At this stage, as mentioned above, there is still a small gap volume between the cylinder and the piston, but most of the air in the cylinder is forced into the chamber 36. At approximately top dead center, additional fuel is injected from injector 74 into chamber 36. The air/fuel mixture trapped within the chamber 40 is ignited by the spark plug 72, with the valve 42 opening the openings 38a, 38b.
It opens by upward movement of the portion 42a. Expanding combustion products from chamber 40 enter chamber 36 along passage 38 and the air/fuel mixture within chamber 36 is combusted with the combustion mixture from chamber 40 . Combustion within chamber 36 causes downward movement of piston 14 within cylinder 12, causing the engine to proceed to an expansion stroke to bottom dead center, and valve 20 then causes the piston to move upwardly within the cylinder. Opens on the next exhaust stroke.

The action of valve 42 is to isolate chamber 40 for a short period of time toward the end of the compression stroke, so that the air/fuel mixture within chamber 40 remains stable throughout the compression stroke when it is ignited. It will be appreciated that it is at a lower compression ratio than the air in chamber 36 being compressed.

The timing of injection into the chamber 36 may be such that injection begins approximately simultaneously with the opening of the valve (low speed operation), continues after opening, or may begin just before opening for high speed operation. It's good.

The combustion products emitted from chamber 40 passing through valve 42 are so rich that partially burned carbon particles appear in the moving gas, which can reduce valve friction. However, steps are taken to ensure that these fine particles do not accumulate in the lower part of the valve sleeve. To prevent this, the spacer 56 is provided with a small orifice 56a, the lower part of which communicates with the chamber 40 via a passage (not visible) in the head 16. In operation, as the bottom of the valve portion 42a passes below the openings 38a, 38b, some gas is trapped within the spacer 56, and as the valve 42 moves further downward, this gas is trapped in the spacer. It is pushed into the chamber 40 through the orifice. Chamber 40 then becomes in communication with chamber 36 again when valve portion 42a is lowered below the opening. At this stage, the engine has just completed intake, so there is no pressure to counteract the action. The interior of the spacer 56 is connected to the chamber 40, thus ensuring that when the charge air in the chamber 40 is ignited and its pressure increases, the pressure inside the spacer and below the valve head will increase as well. be done. Upon subsequent opening of the valve 42,
Any particles of carbon are blown out from the bottom of the sleeve 46 along with the volume being transferred. Constant redirection of the gas flow through the spacer orifice ensures that the orifice remains unobstructed with carbon deposits.

Fuel injector 70 may be timed and directed to spray fuel into passageway 38 . This injection occurs when the air flow into the pilot chamber is not strong or as early as possible before compression begins. This allows fuel injected at high pressure to travel an additional distance into passageway 38. Most of the injected fuel is finely divided and evaporates almost immediately, thus rapidly losing weight and velocity and being carried away by the air entering the pilot chamber. . Due to this action, the remaining droplets moving against the incoming heated air stream experience very high relative velocities, further improving the evaporation properties. However, the largest droplets impinge on the walls of the transfer passage 38 and the underside of the valve 42, where they evaporate.

This method of fuel injection to the pilot chamber is advantageous for several reasons.

(a) The remaining liquid fuel is distributed over the area through which the incoming air must pass as well, and thus:
Equal distribution within the air/fuel charge is ensured.

(b) This effect occurs when the engine is started from a cold state.
When the heat of vaporization is only from the heat of compression, its confinement in the passageway ensures maximum benefit. Also, if some liquid fuel remains attached to the passageway walls of passageways 38 during these cold periods, the continued combustion and release of the pilot charge air within chamber 40 will cause the fuel to evaporate. is swept into the main chamber 36 and burned.

(c) This effect is caused by the cold start caused by plug insulation being lost due to the adverse effects of wetting as the spark plug 72, which is misaligned in the passageway 38 as shown, begins to receive unevaporated fuel. ensure that conditions do not arise that could lead to difficulties.

(d) Under normal operating conditions, rapid evaporation of the fuel is ensured when a small amount of the combustion products of chamber 40 are discharged through this transfer passage at high temperatures and velocities. be done.

These walls exposed in this way are probably 10%
(the passages are therefore arranged in such a way as to ensure adequate cooling).
This heat thus retained from the previous cycle is
Since the fuel is injected into this section to ensure rapid evaporation of the fuel, all the heat absorption during fuel evaporation is absorbed by this section, which would otherwise flow directly into the passage cooling medium. Aided by heat absorption.

Chamber 40 operates on fairly rich mixtures. However, under widely spread load conditions, it is advantageous to arrange the variation of the fuel injection quantity over the entire spark-ignition air-thermal range, which has all the compression stages to vaporize and thus , forming a homogeneous air/fuel mixture. By forming a fuel-rich mixture, the mixture can be easily ignited by a spark plug device even when the engine is cold. It has also been demonstrated that rich mixtures burn at lower flame temperatures, thus reducing the tendency to form nitrogen oxides. Other benefits of this configuration are:
This is because some exhaust products are restricted for recirculation. In addition, the existence of these substances is related to the combustion temperature and NOx
An additional exhaust gas recirculation device forming part of a low-fouling device is advantageous in reducing the formation of
Currently used in automobiles to reduce this difficult form of emissions. The compression level at which valve 42 closes is selected to provide ideal combustion without detonation or uncontrolled pressure build-up using a standard grade of moderate octane gasoline without thiethyl lead additives.

By using the moderate compression ratios described above for chamber 40, problems generally associated with current high compression engines can be reduced. At moderate compression levels, this spark ignition method is not dominated by factors that promote uncontrolled combustion, and therefore the combustion behavior is predictable and easily controlled, especially regardless of engine load. As in the pilot chamber during compression, where the amount of air/fuel remains relatively constant, key factors remain approximately constant. The amount of fuel and air contained in the pilot chamber is selected based on the fuel that needs to be combusted to maintain engine idling speed and to ensure sufficient heat production for the functioning of the main combustion chamber. . This amount is clearly very small, 20-10% of the total cycle charge.

The use of valve 42 to interrupt the compression of the pilot chamber at an ideal level to match the detonation characteristics of the fuel not only facilitates the use of significantly higher ratios to the main chamber, but also allows for slower closure. High pilot chamber compression can be used to promote effective spark ignition of low grade fuels such as a wide range of fuels expected in the future to optimize refining efficiency for negative rock oils or coal liquefied oils. It is.

The rapid closing of the relief valve and the separation of the pilot charge only when it reaches the appropriate compression ratio prevents the pilot charge from creating a pressure increase for ideal spark-ignited quantitative combustion. On the other hand, the displacement device of the engine is independent of the fuel,
The compression can be continued to much higher levels than is possible using 100 octane gasoline, and the compression level is only limited to obtaining an efficient expansion ratio without over-pressuring the cycle. A consideration has been made to maintain the working gas density at a relatively low level compared to automotive diesels, further reducing direct heat losses to engine components.

Combustion within chamber 40 is conducted in such a way that controlled air flow is obtained to ensure reliable spark ignition during use. The chamber 40, with its small geometric dimensions, has a very short flame path and the delay involved from ignition to maximum pressure is correspondingly short compared to conventional combustion chambers.
There is no need for the chamber 40 to be able to rise to a maximum pressure during combustion of the pilot quantity. Ideally, once combustion is established, pressure should be released to chamber 36 and about half the pressure rise is reached. This is also considered to be the ideal pressure that the engine's pistons reach when passing through top dead center in normal ot-cycle function.

Since the variables are minimal, release of pilot air supply at the appropriate time can simply consist of spark timing, as described above. Thus, the ignition delay is predictable and coordinated, while the opening of the release valve is configurable to occur in a coordinated manner at the ideal time during the cycle. With suitable spark timing,
The pilot mass can be released to expand to a lower pressure in the main chamber, and this pressure imbalance is such that the combustion products in the pilot chamber have sufficient velocity and incandescence to promote complete combustion characteristics in the main combustion chamber. and entry into the main combustion chamber. Also, when this imbalance occurs, combustion is still in progress, thus ensuring a strong flame reaction as the products of partial combustion are transferred. Therefore,
The majority of the fuel in the pilot quantity does not release its energy until it enters the main chamber, and this action ensures that the use of this heat and flame function ensures complete combustion and therefore fewer emissions. This is advantageous because it has been found to be very effective. Also, the pilot chamber and transfer passages are not subjected to high thermal loads, thereby reducing direct heat losses in these areas.

two chambers 36 in part of the cycle,
The mechanical separation of 40 provides significant flexibility in the main combustion process. For example, in normal diesel or engine cycle operation, ignition must occur well before the piston reaches top dead center, and the combustion pressures created before top dead center are significant and add to the engine losses. It will be done. However, in the above operating method, the delay time and initial pressure rise are
Displacement components and normal considerations including crank angle effects are derived separately. For example, the configuration may be such that a highly efficient compression ratio of 12:1 is selected as the point at which the thermal energy of the entire fuel charge is to be released. With a suitable balance of combustion chamber volumes, it is possible to carry out compression to even higher levels after separation of the pilot volume, e.g. overcompression to 16:1 at top dead center and elasticity to a level of 12:1 during the normal expansion stroke. make it possible to return. At this point, established combustion from chamber 40 can be introduced along with additional fuel from main injector 74. Since ignition delay is no longer involved, combustion pressure is under direct control of the fuel injection discharge rate.

The above method of operation loses some possible expansion ratio, but is chosen as a compromise. Obviously, the expansion may be increased to 16:1 if desired, but this procedure is detrimental to the purpose of maintaining a light and inexpensively manufactured engine, and eliminates other benefits in other areas. lose. One major purpose of using this overcompression method is to almost eliminate the normal high pressure and temperature combustion within the chamber that cannot immediately expand due to the butt matching involved in the crank action. be. Using this method, the crank is able to pass through its back-and-forth movement action to obtain a significant lever arm, and the volume of the chamber increases about four times faster than normal. However, in a normal cycle, attempting to initiate combustion at this stage is completely unsatisfactory and inefficient. However, with the invention it is possible to obtain a very fast combustion action and therefore an efficient release of the thermal energy of the fuel, which is not related to this expansion.

In conventional practice, the highest cycle temperatures and pressures are obtained if the fuel heating values are released quickly. Although this action is thermally efficient, it is difficult to exploit mechanically in practice. By providing a chamber that rapidly increases in volume over time, rapid release is obtained without incurring the high pressure build-up common to metered combustion. Since the purpose of any heat engine is to convert as much of the thermal energy of the fuel into useful work as possible, the presence of these few places that impose unnecessary mechanical constraints on expansion It only increases fuel losses and heat loads on the engine components.

The engine described above ensures rapid expansion, which is useful in reducing the production of nitrogen oxides. Nitrogen is normally inert during combustion, and its generation is a product of modern engine construction. Nitrogen oxides are produced only in high compression engines with relatively compact and thermally efficient thermal combustion chambers operating under load. Some of the nitrogen present in the air supply is
Conversion to oxides is possible if the temperature and pressure are kept high enough for a period of time, and reducing the time to formation is very useful. Also, combustion of a mixture that is only slightly leaner than chemically correct will produce the maximum amount, but the high compression pressure and therefore density of the gas will ensure the intimate contact required for oxidation. This method of rapidly releasing heat to excess air at moderate pressures and densities, followed by rapid cooling through expansion, typically reduces emissions when considering these factors that influence NOx production. This provides an extremely valuable solution to preventing this difficult-to-control formation, while the characteristic of complete combustion with excess oxygen in the main combustion chamber ensures that the fuel is completely free from harmless water vapor and carbon gases. guarantee that it will change. The primary reason for using the swirl chamber 36 in place of the conventional combustion chamber formed in a recess in the top of the head and/or piston is to reduce emissions. Future regulations aimed at reducing emissions will be so stringent that it is difficult to see how regulations can be complied with in conventional chambers formed by displacement components, and these components , due to practical mechanical reasons, cannot be created without gaps between moving and stationary components, while the position of the valve and spark plug also requires consideration. Because of these factors, the combustion chamber cannot be constructed without a restricted area into which the fuel and air charge is forced, so that it is not completely consumed during combustion; Therefore, it ultimately appears in the exhaust products. The swirl chamber 36 eliminates these problems by burning any fuel before it reaches the piston gap region. Use of this method provides excellent air utilization. However, in order to maintain low emissions, the entire air volume must not be given to combustion, but must be configured such that under full load some air passes through the engine unburned. No. It is for this reason that it is important to have an engine construction capable of high speed operation while its power and bulk remain largely unchanged. This applies in particular to reciprocating engine problem solving methods.

Although these methods are not sensitive to the octane rating of gasoline and can use a wide range of gaseous and liquid fuels, gasoline has been the primary fuel used for motor vehicle transport for many years and its regular form It is ideal for splitting step methods. Gasoline is highly volatile and vaporizes even at standard temperatures, and this volatility is advantageous for combustion because the liquid fuel does not burn until it evaporates. however,
Volatility must not be mixed with the ignitability or heat required to form an instantaneous ignition. Light distillates of diesel oil used in automobile engines have good ignitability and are indicated by high cetane numbers. Heavy diesel oils used in large diesel engines have correspondingly low cetane numbers. Although extremely volatile, gasoline has an equally low cetane number and requires special effort and equipment to burn it in diesel engines.

It has been demonstrated that large diesel engines can be operated at compression ratios as low as 12:1, yielding the best specific fuel consumption available with diesel processes. The use of small pistons is preferred for high speed automotive applications, where much higher compression ratios must be used to offset the loss of compression heat due to the increased surface to volume ratio, and the vortex chamber is , used to achieve high speed operation. These factors indicate that the heat of compression is similarly reduced when using a swirl chamber (chamber 36) as in the method described above. Furthermore, the main chamber 36 is
A suitable water jacket may be provided for cooling, and the construction is compatible with conventional pre-ignition stimulators, i.e.
Unhindered by spark plug electrodes and hot exhaust valves. At high speed, low load conditions, fuel injection may be advanced in injection timing and conditioned to fully mix with the compressed air in the main chamber just before the release of white hot pilot charge air. . This pre-introduction of fuel into the chamber 36 under light load and high speed operation ensures that this fuel and air charge burns quickly as it is preconditioned, or in other words , the molecules of fuel and air are
The evenly distributed, completely vaporized and therefore incandescent pilot charge, when released, gains additional heat as it passes through this homogeneous mixture. This form of combustion is obviously very rapid, but it can be used to ensure the transmission of opposing shock waves, i.e. at high speeds, making it difficult to obtain high speed combustion with very lean mixtures. This feature is extremely important as it is not subject to differential pressures within.

Apart from the low cetane number of gasoline, it is only possible to inject a portion of the total fuel early if a reasonable peak combustion pressure is maintained.
At the compression temperatures considered, the fuel hardly ignites upon injection, and some delay time is included due to the significant air turbulence in the chamber and the volatility of the fuel; is rapidly formed into a rich mixture and is therefore taken out of the range of combustible mixtures. This feature is another reason why diesel engines are so difficult to run on gasoline.

Over the entire load and speed range used in automotive applications, the method of the present invention is ideal.
Under idle or deceleration, the injection of heating material into the chamber 36 can be omitted, and the expansion power of the pilot air charge is completely consumed in excess air, creating a large expansion. A comparison with the Ot cycle under these conditions can be shown, in which the Ot cycle has to burn an overly rich mixture under low compression and its efficiency is very low. The emissions of unburned fuel and partially burned fuel are proportionally much higher. On the other hand, with high compression,
A similar diesel using an air/fuel ratio close to 100:1 can idle so efficiently that its fuel consumption is 15 times lower than that of a gasoline engine.
It is only %.

The method of the present invention allows similar drag or low speed torque at low speeds but under high load conditions as obtained with diesel engines. This is based on the ability to control combustion by using a direct injection method in conjunction with a speed-responsive gahana. It is easy to delay multiple injections at low engine speeds and then progressively advance them as engine speed increases. This method allows fuel energy to be released in a more controlled manner,
The pressure rise is reduced and a more constant pressure expansion is obtained, thus providing smooth high torque in the low speed range. Use of the method under low speed conditions
Not very thermally efficient. However, it is still advantageous from the point of view of the flexibility obtained and the aspects involved in the use of conventional automobile engines.

The configuration described above ensures that the main combustion and highest heat stage of the cycle takes place in a chamber (chamber 36) with ideal equipment and minimal surface area; these characteristics are: Desirable to reduce contaminant production cooling area and direct heat loss. Although these factors are important, inexpensive engines often form the main chamber as a suitably formed recess in the cylinder head or top of the piston and release valve 42.
A controlled transfer passage 38 can be constructed in a conventional manner to place it in direct association with the main combustion chamber thus formed, eliminating the need for a swirl chamber 36.

Also, if the chamber and method described above are used in engines that utilize different displacement components, such as orbiting pistons or rotating pistons,
The positioning of the various components may be arranged in slightly different positions relative to each other due to practical reasons of the modified basic engine geometry, for example, the main communication passage 34 is located in the chamber 36 can be located at different angles from.

Although the engine described above is a four-stroke engine, the principles of the invention are applicable to either four-stroke or two-stroke modes of operation and, as described, are applicable to any type of positive displacement engine. be.

Chambers 36, 40 are formed between the face of the cylinder head and a suitable insert 29 which is held in place by collapse of the cylinder head joint. This insert, made of nimonic steel or a suitable high nickel alloy with high oxidation resistance, is used to reduce direct head losses contained in the chamber by maintaining a high surface temperature, which , is particularly important in reducing heat flow as combustion products are exhausted through main passage 34. Chamba 36
are passages 3 located at opposite ends of the cylindrical chamber.
4, 38 to ensure that the combustion products exiting the chamber 40 through the passage 38 must travel at least once around the diameter of the main chamber, thus reducing the content of the main chamber. Complete mixing and combustion is ensured.

Because the chamber 36 is formed as such a swirl chamber, the majority of the combustion takes place in a compact and well-shaped region with predictable turbulence in relation to the engine speed and, moreover, with a displacement configuration. The advantage is that limited cooling areas, which are difficult to eliminate with conventional chambers formed in part by elements, can be eliminated. Maximum flame temperature and radiation are limited to a relatively small wall area, the largest portion having heat retention liner properties and therefore high residual temperatures, and wall cooling and consequent formation of unburned hydrocarbons. , is considerably reduced. This also gives maximum ease to the requirements demanded of the fuel injector, such factors as the directional characteristics of the fuel spray, the penetration of the spray, and the size of the droplets. is less important when the high air velocity of the chamber is compensated.

The compact nature and high compression ratio of the main chamber that can be used in the split stage method described above
Normal flame propagation is replaced by an ideal form of collective flame transfer when the product of the pilot chamber is released, and when fuel is introduced into the main chamber via the main fuel injector, the release valve The timing of the injection is such that a portion of the injection quantity is introduced just before the opening of the fuel mixture, making complete sintering of lean mixtures to very low levels of fuel content practical. This part of the injection quantity therefore has time to be dispersed and mixed in the turbulent air. As the pilot flame enters the main chamber, this fuel is consumed at the rate of movement of the flame.
With suitable spark timing, the flame speed can be adjusted to obtain the desired combustion rate, while the residual injection volume for well-established combustion is
It can be used to control pressure rise.

When using a swirl chamber such as chamber 36, the cylinder head and piston are flat;
It is important that the clearance between the piston and the head is kept to a minimum at top dead center to ensure that the maximum amount of air at top dead center is available for combustion in the main chamber. be. However, a small portion of the air left in the volumetric chamber can be removed by removing the partially combusted products that are discharged into it.
Still plays an important role under high load conditions.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of one cylinder of the internal combustion engine of the present invention, and FIG. 2 is a sectional view taken along the line A--A of the same. 12...Cylinder, 14...Piston, 16...
... Cylinder head, 18 ... Intake valve, 24 ... Overhead camshaft, 34 ... Passage between cylinder and main chamber, 36 ... Main chamber, 38 ... Passage between main and sub-chamber, 40 ... Sub-chamber , 42...valve,
70, 74...Fuel injector.

Claims (1)

[Claims] 1. A cylinder head 16, a cylinder 12, and a piston 14 that is reciprocated within the cylinder 12 to periodically change the volume of the space between the cylinder head 16 and the cylinder head 16. , a main combustion chamber 36 in continuous communication with said space, an inlet device 22, 70, 74 for periodically introducing an air-fuel component of an ignitable working fluid into said space, and from said main combustion chamber 36. There is also a sub-combustion chamber 40 with a small volume, and these main and sub-combustion chambers 36, 4.
a passage 38 between the auxiliary combustion chambers 4 and 4;
0 is adapted to communicate with the main combustion chamber 36 only through the passage 38, and air can flow into the secondary combustion chamber 4 without passing through the passage 38.
The inlet devices 22, 70, 74 direct the fuel component of the working fluid into both the primary and secondary combustion chambers 36, 4.
In an internal combustion engine adapted to be introduced into an internal combustion engine, the passageway 38 is periodically actuated to control communication between the main and auxiliary combustion chambers 36, 40 through the passageway 38. An internal combustion engine characterized in that it is equipped with a valve device 42. 2. The inlet device comprises fuel injectors 70, 74 for injecting fuel components of the working fluid into both the main and auxiliary combustion chambers.
Internal combustion engine as described in section. 3. An internal combustion engine according to claim 1, wherein said main combustion chamber comprises a chamber formed in said cylinder head 16 so as to communicate with said space via a passage 34. 4. The internal combustion engine according to claim 1, wherein the valve device is movable in a reciprocating manner. 5 The valve device is connected to the overhead camshaft 24 of the internal combustion engine.
5. An internal combustion engine according to claim 4, wherein the internal combustion engine is adapted to be operated from 6. The internal combustion engine of claim 1, wherein said space forms a third combustion chamber in continuous communication with said main combustion chamber. 7. Internal combustion engine according to claim 1, characterized in that an ignition device (72) is provided for igniting the working fluid in the secondary combustion chamber. 8 The inlet device 70 for introducing fuel into the secondary combustion chamber is connected to the passageway 38 in the secondary combustion chamber.
2. The internal combustion engine according to claim 1, wherein the internal combustion engine is disposed opposite to the position where the opening of the internal combustion engine. 9. An internal combustion engine according to claim 4, wherein said valve arrangement includes a valve element (42) adapted for linear reciprocating movement across said passageway (38) to close and open said passageway (38). 10 The valve element 42 is disposed in the middle of the passage and reciprocates so that when the valve arrangement is closed, fluid impinges on a side 42a of the valve element 42, preventing fluid flow through the valve element. Claim 9, wherein the valve arrangement is opened to permit fluid flow over the valve element, the fluid flow being in a direction substantially perpendicular to the direction of the linear reciprocating motion. internal combustion engine. 11 The main combustion chamber has a substantially cylindrical shape with its axis perpendicular to the axis of the cylinder, and the secondary combustion chamber has a substantially cylindrical shape with its axis perpendicular to the axis of the cylinder. 2. The internal combustion engine according to claim 1, wherein both the main combustion chamber and the auxiliary combustion chamber are formed as swirl chambers in which the air-fuel mixture ignited therein undergoes a swirling motion. 12. The internal combustion engine according to claim 1, wherein the piston has a flat top. 13 cylinder head 16, cylinder 12,
a piston 14 adapted to be reciprocated within the cylinder 12 to periodically change the volume of the space between it and the cylinder head 16; a main combustion chamber 36 in continuous communication with the space; an inlet device 22, 70, 74 for periodically introducing an air-fuel component of an ignitable working fluid into the space; a secondary combustion chamber 40 having a smaller volume than the main combustion chamber 36; 36,
40 and a passageway 38 between the secondary combustion chambers 38 and 40 such that the secondary combustion chamber 40 is in communication with the main combustion chamber 36 only through the passageway 38, and the secondary combustion chamber 40 is configured to communicate with the primary combustion chamber 36 only through the passageway 38; 40, wherein at least an air component of the working fluid is introduced into the space from the main and auxiliary combustion chambers 36, 40
Compressing at least the air component within the space and the primary and secondary combustion chambers 36, 40 by creating a flow of air into the cylinder head 16 and moving the piston 14 toward the cylinder head 16. , a method of operation in which a fuel component of the working fluid is supplied into each of the secondary combustion chambers 36, 40, mixed with an air component of the working fluid, and the working fluid in the secondary combustion chamber 40 is ignited. The communication between the two combustion chambers 36, 40 is periodically controlled by a valve arrangement 42, in which case the communication between the two combustion chambers 36, 40 is controlled periodically before the compression of at least the air component in said space and in said main combustion chamber 36 is completed. closes said passage 38 by closing said passage 38 so that at least the air component in said secondary combustion chamber 40 is compressed to a lower degree than the air component in said space and said main combustion chamber 36; The passage 38 is kept closed by the valve arrangement while the working fluid of
8 and while the working fluid in the secondary combustion chamber 40 is still incandescent, the passage 38
remains open, causing a sudden discharge of the ignited working fluid into the main combustion chamber 36 through the opened valve arrangement 42 and the passage 38, and from the secondary combustion chamber 40. The working fluid in the main combustion chamber 36 is ignited by contacting the working fluid in an incandescent state, thereby increasing the pressure in the main combustion chamber 36 and the space to cause the piston 14 to ignite.
A method of operating an internal combustion engine characterized by driving an internal combustion engine. 14. An internal combustion engine according to claim 13, wherein the fuel component of the working fluid is introduced into the secondary combustion chamber after at least partial compression of the air component of the working fluid in the secondary combustion chamber has taken place. How to drive. 15. The method of operating an internal combustion engine according to claim 14, wherein the fuel component of the working fluid is introduced into the secondary combustion chamber after the valve arrangement is closed. 16. The internal combustion engine of claim 14, wherein the working fluid in the secondary combustion chamber is formed by introducing a fuel component into an air component in the secondary combustion chamber before the valve arrangement closes. How to drive. 17. A patent in which the fuel component supplied to the secondary combustion chamber is introduced before the valve arrangement is closed and a part of it flows out of the secondary combustion chamber such that it mixes with the main combustion chamber and the air in the space. A method of operating an internal combustion engine according to claim 16. 18. The method of claim 17, wherein further fuel is introduced into the main combustion chamber after the valve arrangement is closed and before the working fluid in the main combustion chamber is ignited. . 19. The internal combustion engine according to claim 13, wherein the air-fuel ratio of the working fluid in the main combustion chamber before being ignited is lower than the air-fuel ratio of the working fluid in the auxiliary combustion chamber before being ignited. how to drive. 20. The method of operating an internal combustion engine according to claim 13, wherein the combusted working fluid is discharged from the internal combustion engine through the space. 21. The method of claim 13, wherein the ignition of the working fluid in the main combustion chamber takes place after the piston has reached its top dead center position at the end of compression. 22. The internal combustion engine according to claim 13, wherein the piston has a stroke that leaves a small gap between the piston and the cylinder head when it is closest to the cylinder head at a top dead center position. how to drive. 23. The method of operating an internal combustion engine according to claim 13, wherein the final compression ratio of the air-fuel mixture in the main combustion chamber is in the range of 12:1 to 15:1. 24. The method of operating an internal combustion engine according to claim 13, wherein the final compression ratio of the air-fuel mixture in the auxiliary combustion chamber is in the range of 6:1 to 8:1. 25. The method of operating an internal combustion engine according to claim 13, wherein the fuel component is gasoline.