JPH0584367B2 - - Google Patents

Description

Claim 1: (a) the suction, compression, combustion, expansion and exhaust steps are induced and moved within a variable volume working chamber;
(b) a movable piston disposed within a variable volume working chamber, the piston having a working surface defining a movable wall within the working chamber; (b) an air chamber within the piston proximate to the working surface; The air chamber communicates with the working chamber through a gap having a cross-sectional area, such that gas flow from the working chamber to the air chamber is reduced during at least part of the compression stroke during operation of the internal combustion engine above a selected speed. A variable compression type internal combustion engine, wherein the size of the gap cross-sectional area is determined to be approximately 65% of the maximum speed of the internal combustion engine.

2. The variable compression internal combustion engine according to claim 1, wherein the piston and the working chamber are cylindrical, and the working chamber is an annular chamber formed in an upper peripheral area of the piston. institution.

3. Gas is transferred into an air chamber and compressed during the compression and combustion steps, such that the gas flow from said air chamber to the working chamber is reduced during at least part of the expansion phase during operation of the internal combustion engine. 2. The variable compression internal combustion engine according to claim 1, wherein the size of the gap cross-sectional area is determined.

4. A variable volume working chamber and a closely fitted piston movable within the working chamber and changing its volume at maximum and minimum intervals to carry out the suction, compression, combustion, expansion and exhaust processes within the working chamber; The piston has an air chamber that communicates with the working chamber through the working chamber through a restricted orifice, and the normal compression ratio of an internal combustion engine is the working chamber for the sum of the minimum volumes of the working chamber and the air chamber. and the upper limit of the operating speed range of the internal combustion engine during at least part of the compression process, defined as the ratio of the sum of the maximum volumes of the air chambers.
selectively displacing air between the working chamber and the air chamber during at least a portion of the compression process by selectively allowing the compression ratio across the orifice to reach a critical value for only 35% of the time. A method for dynamically and passively varying the compression ratio of an internal combustion engine, characterized in that the selective flow is produced by changing the speed of a piston in a working chamber.

5. The method further comprises the step of selectively generating a flow of compressed air from the air chamber to the working chamber during at least a portion of each exhaust process based on the critical pressure difference between the air chamber and the working chamber. A method for dynamically and passively varying the compression ratio of an internal combustion engine as claimed in claim 6.

FIELD OF THE INVENTION This invention relates to internal combustion engines, particularly variable compression ratio internal combustion engines.

Cross-reference to related applications The content disclosed in this application is based on the following patent application filed by the applicant on the same date as this application, i.e. Application No. "Internal combustion piston engine using a resonant air chamber in a reciprocating piston", Application No. 535337 Title of invention "Piston for internal combustion engine", Application No. 535338 "Internal combustion piston engine using a resonant air chamber in a reciprocating piston ``Combustion Process for Internal Combustion Engines Inducing Closed Tube Resonance'' and Application No. 535340 ``Method of Increasing Combustion Efficiency in Internal Combustion Engines''.

BACKGROUND OF THE INVENTION Description of the Prior Art Devices for effectively varying the compression ratio of piston internal combustion engines are known in the prior art. For example, September 5, 1933
USP1925086 granted to Schneider on
There is. However, this device is itself mechanical and requires a physical adjustment to effectively change the compression ratio to the desired value.

The present invention solves the problem of varying the compression ratio of an internal combustion engine over its operating speed range in a passive and dynamic manner without the need for mechanically moving parts to be adjusted. be.

BRIEF DESCRIPTION OF THE INVENTION The invention pertains essentially to pistons for internal combustion engines. A piston for this internal combustion engine has a piston surface that communicates with the working chamber through an orifice of critical size that prevents sufficient pressure equalization between the gas chamber and the working chamber when the speed of the piston exceeds a certain speed. Contains adjacent gas chambers. For some internal combustion engines, a normal low-speed compression stroke does not result in a choke current through the orifice, during which time there is no flow from the working chamber to the gas chamber with sufficient pressure equalization until the compression stroke is complete. A sufficient flow of gas is generated in the opposite direction. On the other hand, if we consider the compression ratio of an internal combustion engine, at high piston speeds a critical compression ratio occurs at the orifice, resulting in a choke flow through the orifice, which causes a gap between the gas chamber and the working chamber at the completion of the compression stroke. The orifice is sized to prevent sufficient pressure equalization of the
A suitable geometric configuration is given.

In a preferred embodiment of the invention, the choke flow occurs at a speed that is between the upper 35% of the operating speed range of the internal combustion engine or, from another point of view, corresponds to 65% of the maximum operating speed range of the internal combustion engine. piston,
It consists of an operating chamber and an orifice. The compression ratio of an internal combustion engine is lower over a low speed range of the internal combustion engine compared to the compression ratio over a high speed range of the internal combustion engine. The variable range of the compression ratio essentially depends on the degree of compression equalization, which takes place at the end of the compression process between the gas chamber and the working chamber.

The preferred piston is the thermally balanced internal combustion engine developed at the Naval Academy, the Naval Academy Heat.
It has a configuration corresponding to the pistons used in internal combustion engine installations of the type described in the literature published in connection with the Balanced Engine (NAHBE).
For internal combustion engine devices of this type, e.g.
Naval Academy Report No. EW8-76, Name: “Naval Academy Thermal Balance Internal Combustion Engine (NABE)” Blaser, Pouring,
Keating and Rankin (June 1976). That is, the piston of an internal combustion engine is provided with a cap-shaped crown having a smaller diameter area than the main piston. Below the periphery of the cap, an open chamber is provided in the area of the piston with a small cross-sectional area. The release chamber defines an air chamber together with the cylinder hole. This air chamber communicates with a variable volume working chamber on the piston working surface via a gap limited around the cap and between the cylinder bores.

In internal combustion engines of the NAHBE type, this axially laminated charge is placed in the working chamber before it is lowered, so that during compression of the charge the air in the charge is transferred into the air chamber. be done. The communicating combustion that occurs between the combustion chamber and the air chamber causes wave interactions. This wave interaction results in the pumping of air from the air chamber to the working chamber during the combustion process.

The present invention is selectively arranged to create a choke flow condition between the gap and the working chamber and the air chamber during compression of the filling of the volume of the working chamber and air chamber, so that when in the choke flow condition, And when the flow is not choked, less air is transferred to the air chamber.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a piston for an internal combustion engine incorporating the present invention; FIG. 2 is a front view of the piston of FIG. 1 disposed within a cylindrical bore of the engine; 3 is a schematic diagram of a fuel-intake internal combustion engine incorporating the piston of FIG. 1 and having an air-fuel ratio control system, and FIG. 4 shows a direct injection of substances into the working chamber of the engine using a fuel injector; 5 is a schematic diagram of an internal combustion engine similar to FIG. 3, and FIG. 5 is a plan view showing an embodiment of a piston gap constructed according to the present invention, in which the air chamber in the piston and the engine working chamber are This gap between the air chamber and the working chamber is uniform around the top of the piston, and FIG. 6 is a plan view showing another embodiment of the gap;・It is formed by the gap being arranged concentrically within the cylinder bore, and the seventh
The figure shows yet another embodiment of the gap formed according to the present invention, in which the gap is non-uniform and divided and arranged around the piston. 2 shows a detailed cross-section of the piston of FIG. 1 having an alternative shape,
FIG. 9 is a front view of the cross section of the piston in FIG. 1 showing another structure of the piston cap, and FIG. 10 is a front view of a cross section of the piston shown in FIG. 1, showing another structure of the piston cap, and FIG. FIG. 11 is a schematic diagram showing the similarity to the chamber; FIG. 11 is a diagram schematically showing the closed sound tube resonance induced in the working chamber by a resonant piston chamber; FIG. 12 (a-b) 13 is a diagram depicting the operating cycle of an engine incorporating the present invention, and FIG. 13 is for illustrating the horsepower of an engine constructed according to the present invention.
A series of graphs of the air-to-fuel ratio of the injectate delivered to the working chamber of the same engine, including specific fuel consumption, unburned exhaust hydrocarbons, exhaust carbon monoxide (volume percent), and the engine's "run" ratio. Figure 14 shows the pressure and temperature of the combustion chamber, the spontaneous ignition region of the injected material in the combustion chamber, and the rapidly increased spontaneous ignition region of the injected material in the combustion chamber. It is a figure showing the correlation between.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION With reference to the drawings, and in particular to FIGS. 1-3, the present invention has a cylinder 12 and a piston 14 that reciprocates within the cylinder 12, and has a suction charge stroke, a compression stroke, a combustion/ It is intended to improve an internal combustion engine 10 that operates with an operating cycle consisting of an explosion stroke and an exhaust stroke. In internal combustion engines, naturally aspirated
It is supercharged (intake air is pressurized), mixed, and fuel injected, or a combination thereof, and what is inhaled is usually a mixture of a suitable hydrocarbon fuel and air. All of these things are well known in the field of internal combustion engines. The particular preferred embodiment illustrated is a reciprocating piston type internal combustion engine;
The inventive concepts disclosed and claimed herein are contemplated to be equally readily applicable to internal combustion engines of the rotary piston type.

As shown in FIGS. 1 and 2, a piston 14 constructed in accordance with the present invention is disposed within cylinder 12. As shown in FIGS. As the piston 14 reciprocates, the piston 14 defines a variable volume working chamber 16 (designated as a "combustion chamber") between the top of the piston 14 and the closed end of the cylinder 12. The piston 14 has a conventional guide or skirt 20, a seal ring groove 22 for a seal ring 24, and a piston pin bearing 26 at the connection point between the piston 14 and a connecting rod 28. A connecting rod 28 connects the piston 14 to an output crankshaft 30 of the internal combustion engine 10. Piston 14 is cylinder 1
2 with a clearance CL (Fig. 2), the piston 14 is fitted with a clearance CL (Fig.
and top dead center (TDC).

A piston 14 constructed according to the invention has a working end which is connected to a crown or cap 3.
It has 2. The cap 32 has a diameter dimension, the diameter of the cap 32 being smaller than the diameter of the skirt portion 20. The cap 32 usually has a symmetrical body, the diameter d of which is equal to the skirt portion 2.
The diameter is reduced compared to the main diameter D of 0 (see FIG. 1). If only the radius is considered, cap 3
2 is shown as having a reduced radius r compared to the major radius R of the skirt portion 20 (FIG. 1). As shown in FIG.
is placed in the cylinder 12, it is clear that the width of the gap g is given by the difference between R+CL and r. For example, as shown in FIG.
It can be defined by the lateral dimension between the imaginary cylindrical surface 34 spanning between 2 and r. The imaginary cylindrical surface 34 has a diameter substantially equal to the bore B of the cylinder 12 (or the diameter D of the skirt 20 of the piston 16 if the clearance CL can be ignored). The imaginary cylindrical surface 34 can be viewed as the locus of the bore of the cylinder 12 that receives the piston 14, or, if the above-mentioned clearance can be ignored, as the locus of the curved surface defining the upper part of the skirt portion 20. In the following description and claims, the clearance CL between the piston 14 and the bore will be referred to in the calculation of various mathematical relationships and geometries in order to avoid complicating the description of the invention. are largely ignored. If the clearance CL cannot be ignored, taking into account the dimensions of the clearance CL will be easily understood by those skilled in the art in making such calculations.

As shown in FIGS. 5, 6 and 7,
Cap 32 can be configured in different shapes. For example, the cap 32 shown in FIG. 5 is a protrusion extending concentrically from the piston 14, and there is a uniform gap around the entire circumference of the cap 32. The cap 32 shown in FIG. 6 is an eccentric but symmetrical projection, and the gap g around the cap 32 varies uniformly. Further, as another shape that satisfies the geometrical requirements of the present invention, there is, for example, the shape shown in FIG. The cap 32 in FIG. 7 is shaped to divide the gap into two regions, and the gap has a width that varies circumferentially around the piston 14 or bore. Various shapes of the gap and cap result from the application of the invention to various types of internal combustion engines and are necessary to match the desired operating cycle. However, as will be apparent from an understanding of the concept of the invention described below, the piston (including the cap) and combustion chamber embodying this invention all depend on the various parameters of the internal combustion engine to which this invention is applied. and related by certain mathematical relationships involving dimensions.

The piston 14 having the above-mentioned NAHBE type piston characteristics is provided with a reduced diameter portion 36 below the cap 32 and above the skirt portion 20, that is, the seal ring groove 22. This reduced diameter portion 36 forms an air chamber 38 below the cap 32 and above the seal ring 24.
communicates with the working chamber 16 only via the gap g. In other words, the air chamber 38 has a reduced diameter portion 36 which is the innermost portion in the radial direction, and a bore or imaginary cylindrical surface 34 of the cylinder 12 which is the outermost portion in the radial direction. upper and lower surfaces 40, 42 that converge;
It is completely defined by the gap length L and the length of the upper gap (LR) of the top seal ring.
In the preferred embodiment, the piston 1
4 intersects the periphery of the cap 32 of the piston 14 along a sharp edge 44 (FIG. 2).

The peripheral region of the cap 32 includes an axial surface 46, which axial surface 46 has an axial length L. This axial length L defines the length of the gap. In this preferred embodiment, the axial surface 46 intersects the working surface of the piston along an inclined surface 48. According to the invention, the axial length L of the gap g is an important dimension along with the width g of the gap, the volume V _B of the air chamber 38 and the geometric dimensions of the upper and lower surfaces 40, 42. The volume V _B is correctly calculated and contains _{the volume V g of} the gap g. This volume V _g is calculated by multiplying the area of the gap (obtained by integrating the circumferential length of the gap around the piston (see Figures 5 to 7) by the width of the gap) and the axial length L of the gap. This axial length L is obtained by multiplying the axial length L of the cap by
Measured along the circumference of 6. Such length and volume determinations are made by formal mathematical principles and require no effort. Further, as shown in FIG. 1, the volume V _B of the air chamber 38 is equal to the volume V B of the top seal ring groove 22 along the gap surface 50 between the piston 14 and the bore 12 (imaginary cylindrical surface 34).
It is calculated including the gap volume V _C extending to the upper periphery. However, the interstitial volume V _C will be largely ignored in the discussion and description of this invention, except in specific cases where its significance is particularly important.

In FIG. 2, the upper and lower surfaces 40, 42 of the air chamber 38 are shown to be smooth, but in the modification of FIG. 8, at least the upper surface 40 has radially and axially projecting fins. It is shown. These fins assist in heat exchange between the air circulating within air chamber 38 and the underside of cap 32 during operation of the internal combustion engine, as will be explained in more detail below.

Furthermore, the structure of the piston 14 in another embodiment is illustrated in FIG.
Reference numeral 2 designates a separation member 54 that is assembled to the main body of the piston via a suitable fixing member 56 or via other suitable fixing mechanisms including brazing or welding. The upper and lower surfaces 40, 42 are also coated with a suitable catalytic material 58 to promote radicals in the air chamber 38 or to assist in controlling the force of chemical reactions occurring within the air chamber 38. You can also.

Conventionally, for example, in an internal combustion engine 10 that uses a piston similar to piston 14, the determination of its compression ratio is determined by the ratio of the total volumes of the working chamber and air chambers 16 and 38, respectively, when the piston is at BDC and This can be easily done by comparing the volumes of the working chamber and air chamber at TDC. The volume of the working chamber when the piston is at TDC is conventionally designated as the "free" volume of the working chamber. For convenience,
The volume of the air chamber is often designated simply as "V _B ", and the ratio of V _a to V _B is customarily designated as "equilibrium" from the early theoretical "thermal equilibrium cycle" terminology. In this theoretical "thermal equilibrium cycle" terminology, heat is considered to be added to the theoretical air cycle at "equilibrium". If additional information is desired regarding the theoretical thermal equilibrium cycle that provides the background for this invention, reference may be readily made to the various publications containing the term theoretical "thermal equilibrium cycle" mentioned above.

A typical internal combustion engine system employing the present invention is shown in FIGS. 3 and 4. FIG. 3 schematically shows a typical fuel-breathing internal combustion engine, and FIG. 4 shows a typical fuel-injection internal combustion engine. Each internal combustion engine includes a piston 14 of the shape shown in FIGS. 1 and 2, and a suitable functional mechanism for connecting the piston 14 to an output shaft 30 having a flywheel 60 attached thereto. In Figure 3,
The intake type internal combustion engine has an intake manifold 62 through which a mixture of combustible air and fuel is passed under the main control of a throttle 66.
It is supplied to the intake port 64 of the internal combustion engine.

In a preferred embodiment of the invention, fuel is added to the first air stream 68 that is supplied to the intake manifold, and the second air stream 70 is provided with its own separate control system. This control system will be described below in connection with the description of FIG. The schematic implementation of FIG. 3 shows the first and second air streams connected to a common manifold. Separate manifolds, along with other devices, are utilized to provide separate supply and control of the first and second air streams supplied to the working chamber of the internal combustion engine. In all cases, the first and second air flows (along with the necessary fuel) are suitably regulated or controlled, so that during each intake stroke, only air or a very small proportion of fuel fills the working chamber. Air containing air (which is insufficient for fuel continuation) is first drawn into the working chamber and, after a delay, a rich mixture of fuel from the main side of the charging source. Therefore, when combustion begins, virtually only air is in the vicinity of the piston, and all of the fuel in the total charge (including all air and fuel in the working chamber when the intake port is closed) is It is included on the end side of the working chamber opposite to the piston. As the compression of the charge proceeds, the air containing very little fuel is transferred via the gap g to the air chamber 38 below the piston cap 32, where it is compressed together with the rest of the charge in the working chamber. and heated. The geometry of the air chamber 38, in particular the upper and lower sides 4
The geometry of 0,44 causes the air moved into the air chamber 38 to swirl rapidly on the underside of the cap 32 in an annular swirl pattern, which causes this air to flow into the upper and lower sides 40,42. It is circulated with direct heat exchange between the two. The heat exchange that takes place between the displaced air and the piston cap (particularly the upper side 40) is very important. This is believed to be the basis for improving the efficiency of the working cycle in the present invention compared to engine and diesel cycles with conventional piston geometries. Essentially, the heat exchange that takes place during the subsequent compression stroke between the cap heated by the previous compression/explosion stroke and the air moved below this cap creates a regenerative effect, and this The regenerative effect reduces the total waste heat during each cycle for a given amount of fuel compared to conventional engine or diesel cycles. Therefore, if necessary, the eighth
The use of fins and catalyst surfaces as illustrated in FIGS. It can be done.

Normally, a small amount of fuel is carried into the air chamber 38 with the air, so that some hydrocarbon radical generation occurs in the air chamber 38 as well as in the working chamber 16. Radical-generating reactions of hydrocarbon fuels under high pressure and high temperature conditions are described, for example, in U.S. Pat.
It is known from reference No. 4317432 and
The phenomenon is described here. The generation and treatment of radicals generated within the air chamber 38 and how they are used to contribute to the main reaction within the working chamber 16 is illustrated in FIGS. 12a to 12.
Discussed below in conjunction with the description of p-diagrams.

In FIG. 4, an internal combustion engine 72 uses a similar piston 14. However, for the fuel intake system illustrated in FIG. 3, fuel is injected using an injector 72. The injector 74 shown as supplying high pressure fuel directly to the working chamber of the internal combustion engine or an alternative fuel injection device is utilized, these provide axial stratification in the working chamber at the beginning of the compression stroke. Guarantee. Also, indirect fuel injection in the area of the intake port gives rise to the necessary layer control, but
The invention is not limited to a given injector system based approach; in FIG. 4 fuel is supplied via an injection controller 79 responsive to the position of throttle 79'. In both the internal combustion engine embodiments of FIGS. 3 and 4, the exhaust port 80
is connected to an exhaust manifold 82 for exhausting combustion products from the working chamber 16. In FIG. 3, a spark igniter 84 serves to initiate the combustion reaction within the working chamber 16 in the conventional manner, and this igniter 847 is supplied with a high energy electrical potential via a distributor 86. Ru. Thereby, sparks can be generated within the working chamber 16 at a timing related to the movement of the piston 14. In the embodiment of FIG. 4, ignition is either compression induced or spark driven.

According to the invention, it is desirable to use shock wave energy for ignition of the combustion chamber charge in order to operate the air chamber as a Helmholtz resonator. Helmholtz resonators are generally well known and widely described in the literature. The classic discussion of the Helmholtz resonator in the combustion chamber environment of an internal combustion engine began in 1951.
A. on October 30th. G. U.S. Patent Granted to ADBodine, Jr.
It can be seen in No. 2573536. This patent relates to a process for weakening or eliminating detonation waves in combustion processes.

In FIG. 10, the upper part of the figure shows a classical Helmholtz resonator comprising a chamber 90 containing gas at a predetermined temperature, the chamber 90 having a restricted aperture or neck 92.
have. This net 92 has a length Ln,
It has geometric orifices at both ends.
When the air in the network 92 is given an excitation frequency corresponding to the natural resonance frequency of the gas in the chamber 90, a resonance condition is generated in the chamber 90, and the gas in the chamber 90 is oscillated at the Helmholtz resonance frequency and , the transmitting state is maintained even with relatively small input energy. Diameter at net 92,
Although the cross-sectional area and length Ln and the volume of the chamber 90 are variable and determine the oscillation state of the chamber 90, the Helmholtz resonator theory is quite general with respect to the actual shape of the chamber 90 itself. . Accordingly, the invention provides that, when the piston is positioned within the bore, in response to periodic pressure wave energy applied from the working chamber to this air chamber via the gap g,
It is based on the assumption that the air chamber 38 of the piston structure shown in FIG. 1 or 2 can react exactly like a Helmholtz resonant chamber 90. When the members constituting the Helmholtz resonance chamber have a suitable shape, at the temperature of the chamber 38,
Input pressure wave energy whose frequency matches the Helmholtz resonant frequency of the gas in chamber 38 induces a resonant condition in air chamber 38 in a manner similar to the system depicted at the top of FIG. The similarity between the classical Helmholtz resonator chamber configuration and the Helmholtz resonator obtained by the shape of the piston 14 is
Illustrated at the top and bottom of the figure. In calculating the resonant frequency of the Helmholtz resonance chamber 90 (i.e. 38), the length Ln of the net is important, and the length Ln of the net is appropriate depending on the geometry of the entrance and exit ends of the net. must be adjusted by a dimensionless constant. For example, a flanged inlet provides the neck with one effective length, while the angled inlet shown at the bottom of FIG. 10 provides the neck with a different effective length. In practice,
For the slanted entrance shown in the lower chamber configuration of Figure 10. 6 and. A Helmholtz correction factor between .85 and .85 is provided to adjust the actual neck length to obtain the effective neck length "suggested" by the resonant system.

If optimum efficiency and operation of the piston and combustion chamber is to be achieved, an important aspect of the present invention is to provide the combustion chamber with a periodic impulse frequency transmitted at a velocity close to the speed of sound in the combustion chamber. To find a certain relationship that necessarily exists between the ignition of the charge and the expansion frequency of the explosion; the geometrical dimensions of the cylinder; the volume of the air chamber; the width of the gap; the length and cross-sectional area; and the combustion temperature. Furthermore, when applying this invention to different types of internal combustion engines, it is important to understand these relationships and to understand the relationship between pistons, combustion chambers,
It is important to set the shape and volume in the gap and air chamber. NAHBE utilizes an air chamber that responds to combustion wave interactions as described above.
Internal combustion engines are already in practical use, but "thermal equilibrium"
That is, optimization of an actual internal combustion engine to reach the theoretical efficiency limit indicated by the "regeneration" theory has not yet been easily achieved in a practical form. This invention is therefore based on more recent discoveries;
It is possible to mathematically define the shape, compression and its movement of the piston of an internal combustion engine using a given fuel and with a given cylinder bore, which ensures Helmholtz resonance conditions and creates an optimal internal combustion engine. operation can be obtained.

In particular, assuming that the ignition of the charge in the working chamber 16 creates a periodic vibrational shock wave of frequency _A that is transmitted within the working chamber at a speed close to the speed of sound.
During the combustion/explosion process of the cycle, the air chamber changes its natural frequency like a Helmholtz resonator due to _{the A} frequency.
Under FB, it is configured in a shape that is operated at Helmholtz resonance. On the other hand, the cylinder bore, the air chamber 38,
The geometric ratio of the gap g, the axial gap length, and the gap cross-sectional area is determined by the following equation.

V _B = SC ² / (L + K _g ) (2πF _B ) ² cm ³ where (all dimensions use metric units), V _B is the volume of the air chamber 38; S is the cross-sectional area of the gap g; C is the the sound velocity in the air chamber 38 at approximately the autoignition temperature of the compressed charge in the working chamber 16; L is the gap length; K is for adjusting the effective length of the gap based on the shape of the end regions of the gap; 6 and. 85; _B is equal to (K/B)Hz, where K is
is a number between 43000 and 51000, B is the bore diameter (or piston diameter if clearance is ignored); and g is g=. 01072B+. 1143, and its tolerance is +. From 050-. It is in the range of 025cm.

If the gap g varies around the piston, a uniform gap with the above-mentioned dimension g exhibits a cross-sectional area s. The actual gap area must satisfy the area value related to the gap shape. The maximum width of the non-symmetrical gap cannot exceed the dimension that occurs when a choke flow (critical pressure ratio) is obtained between the air chamber and the working chamber during at least some strokes of the working cycle of the internal combustion engine. Therefore, when the oscillation frequency _A is applied to the working chamber, the total gap area and volume must satisfy the requirements of a Helmholtz resonator.

Furthermore, the gap length L is initially selected to always cut off any flame propagation between the working chamber and the air chamber. (Assuming there is a pocket or region of combustible mixture in the air chamber, i.e. assuming that the air chamber is filled with fuel before the flame front travels through the combustion chamber) Assuming that this L is normally related to the absolute temperature of combustion in the working chamber and the pressure of the working chamber, it is conventionally determined by the flame propagation cutoff theory of the following equation.

L∝(K)(TA) ^1/2 /PA Here, K is a constant; TA is the combustion temperature of the fuel in the working chamber; PA is the pressure in the working chamber;

Also, in the above equation for V _B , the maximum linear dimension of the gap and air chamber in any direction is the resonant frequency within the air chamber 38 at the temperature of the air chamber 38 during the combustion/explosion stroke of the internal combustion engine's operating cycle. It is assumed to be smaller than 1/4 wavelength of _B.

It is desired to obtain a reasonably wide frequency response between _A and the resonant condition in the air chamber, or what is called the "Q" response, and the following equation is
Used to "adjust" dimensions that satisfy VB formulas.

[Chemical formula] When the dimensions of L, g, and S satisfy both equations V _B and Q, an appropriate dimensional relationship according to the present invention is established. Appropriate balance ratios, gap geometry, and air chamber volumes are provided for a given fuel, compression ratio, bore size, and stroke of the internal combustion engine.

Another aspect of the invention is that, with appropriate "adjustment" of the variables mentioned above, combustion of the working chamber at the end of the expansion stroke of the working cycle is achieved by "sound tube" oscillation of the working chamber on the working surface of the piston. This is the discovery that intense mixing occurs in the region. The principle of sound tube resonance in a closed tube is well known, and its fundamental resonant frequency depends only on the length of the tube and the speed of sound at the gas temperature within the tube. In this invention, a frequency of approximately _B (which is somewhat different from _A , since the working chamber is cooled below the original combustion temperature) is used to actuate the working chamber in sound tube resonance for at least a small period of time. When the piston reaches BDC by using the resonant gas in the original air chamber (natural frequency), it induces a fundamental or harmonic resonance in the cylinder bore above the piston. However, in theory, it should be possible to activate the working chamber at multiple points during the expansion stroke when the tube resonates. The principle of sound tube resonance is illustrated in FIG. 11A, where the piston 14 has reached BDC and the air chamber 38 _is
It resonates at or near this frequency. This air chamber 38 causes the working chamber to oscillate at a temperature TA and has a length LW at its fundamental tube frequency, as shown schematically by dashed line 94.

It is important to emphasize the significance of the heat exchange that occurs between the cap 32 and the air in the chamber 38 during the latter part of the compression stroke of each operating cycle. The previous cycle's heat storage in the cap contributes significantly to the overall efficiency of the cycle, so the temperature of the cap is important. The temperature of the cap is controlled by selecting suitable materials for the cap and by coupling the cap to the main piston body to achieve and maintain the desired cap temperature during operation of the internal combustion engine. I can do it. To ensure that _B matches _A , the temperature of the air chamber 38 must be controlled with the pressure at the time of fuel ignition to obtain the desired Helmholtz resonance, which is important for satisfying the operation of the system of this invention. Must be.

Furthermore, in a spark ignition internal combustion engine,
It is important to maintain the temperature of the air chamber 38 at its pressure below the detonation or "knock" temperature of the fuel in the working chamber, thereby avoiding engine knock under all operating conditions of the internal combustion engine. The air chamber 38 also includes an air chamber 38, as described in detail below in connection with FIGS. 12a-12p.
The temperature of must be controlled, so that
The generation of radicals in chamber 38 and the maintenance of radicals imported (or already in chamber 38)
This is ensured by maintaining the temperature of the chamber below such a temperature that the radicals within it do not react with the required compound, with a view to enhancing combustion.

In addition to obtaining suitable piston and combustion chamber geometries for a given internal combustion engine according to the above-described formulas, the present invention also provides methods for providing a working chamber of an internal combustion engine using the piston and chamber of the present invention. The present invention seeks to provide an internal combustion engine regulation system that is applied to control the air-fuel ratio of the charge. If spark ignition is used to start combustion,
In addition to the air-fuel ratio, the ignition timing advance setting is controlled.

As a starting point, the internal combustion engine 10 or 72 (FIG. 3 or 4) is completely "measured" on a suitable test stand (not shown) and the air/fuel ratio of the internal combustion engine; ignition timing; indicated horsepower; Fuel consumption; engine speed; load; fuel flow rate; emissions (especially non-combustible hydrocarbons and carbon monoxide) are determined.

As shown in Figure 13, a set of curves is obtained from the engine measurement procedure, which curves include carbon monoxide (CO), uncombustible hydrocarbons (UHC), indicated fuel consumption (ISFC) and its total operating The figure shows the indicated horsepower (IHP) for air and fuel efficiency of internal combustion engines over a range of ranges. Empirical experiments in the laboratory have shown that when the piston and combustion chamber geometries obtained by the above-mentioned formulas are utilized, the air/fuel efficiency at maximum power is approximately 16% for all internal combustion engines. :1, and the air/fuel efficiency in the most economical case is approximately 20:1. Therefore, 16:1 at maximum output,
Also, an air/fuel ratio variable range varying over a range of 20:1 in the most economical case is obtained, and an initial fuel and air distribution system for an internal combustion engine with a piston and combustion chamber of the invention is established. However, the problem of controlling air fuel consumption under other operating conditions of the internal combustion engine to obtain the maximum efficiency allowed for the internal combustion engine remains.

In order to achieve the maximum permissible efficiency, the invention provides that at various operating speeds of the internal combustion engine:
Recently developed characteristic curves for CO, UHC, ISFC and IHP for air/fuel efficiency are used.
“RunQuality Index”
The curve called “Index)” or ROI is calculated mathematically using the following formula.

RQI=(IHP)K/(ISFC)(UHC)(CO) The RQI curve is also illustrated as curve 106 with its ordinate on the right side of FIG. Therefore, in reality, a curve 106 with a sharp peak indicates the optimum air-fuel ratio for optimum running of the internal combustion engine.
To obtain the RQI curve, the RQI curve relates to what is supplied to the combustion chamber and exhausted to the exhaust stream. It is clear that at maximum RQI, the internal combustion engine actually operates at maximum efficiency at any speed and load condition. Of course, this efficiency need not be equal to the theoretical maximum efficiency under similar conditions. The maximum RQI curve is the target for achieving the charged air-fuel ratio as well as proper ignition timing during actual internal combustion engine operation. However, in all operating conditions of the internal combustion engine, the air-fuel ratio and ignition timing (assuming spark ignition) are controlled so that the composition of the charge can be adjusted in the direction of obtaining the maximum RQI of the internal combustion engine. It is necessary to obtain suitable control means that can do this.

It is assumed that during the internal combustion engine measurements described above, the optimal air-fuel ratio and ignition timing that yields the optimal RQI in the RPM test for each internal combustion engine is determined. Still further, in accordance with the present invention, the air-fuel ratio of the initial charge flow supplied to the intake manifold 62 of the fuel-breathing internal combustion engine shown, for example, in FIG.
The air-fuel ratio is adjusted to approximately twice the optimum economical air-fuel ratio at maximum power operation of the internal combustion engine, and the secondary air is adjusted to balance the overall air-fuel ratio. The secondary air (indicated at 70 in FIG. 3) is provided with a control mechanism which controls the control mechanism at various internal combustion engine load and speed conditions.
Constantly adjusting the amount of secondary air supplied to the internal combustion engine's intake manifold to provide an air-fuel ratio that operates the internal combustion engine at optimal RQI.

According to this invention, the secondary air is
By using a "lean limit control" system, such as that disclosed in U.S. Pat. No. 4,368,707, issued to
It is only controlled by modifying the system described above to seek a "lean limit" corresponding to the RQI. Of course, the patented system does not depend on RQI operation.
Determine the minimum misfire lean limit for an internal combustion engine. However, by appropriately adjusting its measurements, the system determines the optimal air/fuel ratio for internal combustion engine operation at optimal RQI, thereby eliminating any "misfire" on either side of maximum RQI. The situation can be seen. The system responds by adjusting the air/fuel ratio towards maximum RQI.

Thus, referring to FIG. 3, secondary airflow is controlled by a restrictor plate or valve 110 which is controlled by a servo motor 112. Referring to FIG. This servo motor 112 is
It is controlled by a central control unit of a lean limit control system similar to that described in No. 4,368,707. The lean limit control system described in the above patent instantaneously detects the output of the internal combustion engine by instantaneously magnetically detecting the angular velocity of the flywheel 60 using the pickup 116. The pick-up 116 instantaneously detects the passing speed of the teeth of the flywheel in the vicinity of the pick-up 116. After receiving the sensor signal via line 118, the speed signal is processed in central control unit 114 to generate an instantaneous acceleration (or deceleration) signal. Central control unit 114 "interprets" the instantaneous acceleration or deceleration signal as an instantaneous power reading of the internal combustion engine and commands servo motor 112 to go "lean" or "rich", thereby causing valve 110 to go lean or rich. It is opened or closed to obtain a rich state. The predetermined air/fuel ratio determined by control system 14 corresponds to the air/fuel ratio that produces the optimum RQI, as shown by curve 106 in FIG. In this respect, it is recognized that the internal combustion engine operates with an optimal balance between the fuel supplied to it and the power required, and that the internal combustion engine operates at the maximum efficiency it can obtain. But it works. Of course. Misfire is sensor 1
If detected by 16, this indicates to central control unit 14 that the air/fuel ratio is inappropriate and must be further adjusted to obtain the required power output of the internal combustion engine. However, if the sensor 116 recognizes that the misfire limit has been reached and the central control unit 114
Upon determining the secondary air controller 112 to be configured to produce an air/fuel ratio consistent with RQI;
It can be easily recognized that the internal combustion engine operates at maximum efficiency available.

Preferably, an ignition timing controller 120 is provided which controls the advance/retard settings of the test reviewer at the request of the central control unit 114, thereby ensuring that the appropriate timing determination as determined by the aforementioned internal combustion engine measurement tests is provided. According to the setting, each
Optimal ignition settings are established for RPM. Therefore, the central controller 114 receives internal combustion engine information from the flywheel sensor 116 in addition to the "lean limit control" system currently being discussed.
comprising a sensor that receives or derives an RPM signal;
This sensor generates a signal responsive to a speed signal that controls the distributor's spark advance mechanism 120 via line 22.

In an internal combustion engine in which combustion is initiated by self-ignition, such as the internal combustion engine shown in Figure 4, which uses a compression ratio of 5 to 9:1, the optimum
To maintain RQI operation, a lean limit controller 114 is provided that controls a fuel injection control system 79 that adjusts the air-fuel ratio. The timing and amount of fuel delivered to each cylinder of a fuel-injected internal combustion engine is carefully controlled by control system 114 to obtain the precise air-fuel ratio necessary for optimal RQI operation of the internal combustion engine. Additionally, of course, the control system 114 ensures that no fuel is supplied into the working chamber 16 during the compression stroke, which would adversely affect the transfer of fuel-free air into the air chamber 38.

In a preferred embodiment of the invention, in at least a portion of the high operating speed range of the internal combustion engine, during at least a portion of the compression stroke, the classical critical pressure ratio for producing a choke flow through the orifice is determined by the air thrust volume V _B A gap g is formed between the working chamber volume V A and the working chamber volume V _A . By starting the ignition timing of the filling, the operation and air chambers 16,
Assuming that the pressures between 32 and 32 are not equal, the invention provides an internal combustion engine with a dynamically variable compression ratio that depends only on the speed of the internal combustion engine. As the speed of an internal combustion engine increases, its effective compression ratio also increases to increase power output. At low speeds, when no flow is induced, the piston of the internal combustion engine
The volume of the working chamber and the piston when it is at BDC are
According to the ratio between the volume of the working chamber when at TDC, it actually operates at a lower compression ratio in volumetric terms. Preferably, the gap g is selected such that choke flow is present over the upper 35% of the speed range of the internal combustion engine. However, the above-mentioned speed ranges may be varied to suit specific requirements. It can be seen that if the gap g is constant, the maximum width of the gap does not exceed the value necessary to obtain a choke flow between the air and the working chamber above the threshold speed, where the air flow through the gap g Due to the lack of pressure in the working chamber causing it to flow into chamber 32, the effective compression ratio begins to increase.

Furthermore, it can be seen that when the pressure in the working chamber suddenly decreases, a choke flow between the air chamber and the working chamber is obtained at the moment the exhaust valve opens. By appropriately selecting the gap width that produces a critical pressure ratio across the gap when the exhaust valve is opened,
Expansion of the high pressure gas in the air chamber into the working chamber is momentarily delayed. Thereby, the delivery of high-pressure, high-temperature air containing radicals from the air chamber to the exhaust system is maintained and controlled. Of course, the degree of heated air and radical retention will depend on the degree of throttling and other factors. For example, by providing a sharp edge 44 at the edge of the gap adjacent to the air chamber 33, the choke flow can be ensured at a practically normal gap width.

12a-12p, the operation of the present invention is schematically illustrated in which a Helmholtz resonance condition is shown which causes periodic pumping of air from the air chamber 38 into the working chamber 16. Use; flow conditions between air and working chamber;
including acoustic tube resonance; coupled oscillators; and radical generation/management to improve and control the compression stroke of an internal combustion engine.

Starting from FIG. 12a, the piston 38 is
BDC, both valves (intake and exhaust) are closed,
Then, an axially layered filling is shown in the working chamber 16, with air and a very small amount of fuel on the side close to the piston, and a rich mixture near the closed end of the working chamber. It is represented. In all cases, at the beginning of the compression stroke, no or very little fuel-containing air is present in order to ensure that air is introduced into the air chamber 38 at least at the beginning of the compression stroke. Air must be present near the working end of the piston.
Such axial layers can be obtained using a variety of fill control devices, including, but not limited to, dual air supply intake manifolds containing air controls; This includes the intake valve mechanism, fuel injection control, intake manifold port mechanism, etc.

The compression stroke begins and progresses as shown in Figures 12b and 12c, and is indicated by arrow 1 in Figure 12b.
Air enters the air chamber from the working chamber as indicated by 23. As the compression stroke progresses, a roll vortex 124 forms in the air chamber under the cap 32 due to the geometry of the gap g and the walls of the air chamber, and the movement of the fluid within the chamber. This roll vortex is important. This is because this roll vortex creates an intimate heat exchange between the air entering the air chamber and the underside of the cap 32, and after several cycles the air chamber's Helmholtz resonance frequency _B
The cap will be heated to the desired temperature such that A corresponds to the natural frequency _A of the working chamber as described above. If the internal combustion engine is configured to have a dynamically variable compression ratio as described above,
Actuation and initiation of the choke flow between the air chambers 16, 32 occurs at some point during the compression stroke when the piston reaches maximum speed.

Then, when the piston reaches TDC, the air in the air chamber 16 has been heated to such a point that its temperature matches the desired Helmholtz resonance frequency _B , and ignition of the charge occurs (Figure 12d). The generation of radicals in the air chamber 38 is already underway before the ignition point of the fuel, which is determined by the pressure and temperature conditions of the air chamber and the nature of the fuel combusted by the internal combustion engine. However, since the fuel in the air chamber is very small, as will be explained repeatedly, the content of radicals generated from the small amount of fuel contained in the air is the same as that in the air chamber generated in the working chamber during the previous cycle. can be easily recognized to be smaller than the amount of radicals.

In Figure 12d, the ignition has started and the shock wave preceding the flame tip has not yet reached the gap between the actuation and air chambers, and the shock wave from the ignition has not yet reached the gap, as shown in Figure 12e. It passes through this gap and drives the heated gas in the air chamber resonantly at the Helmholtz resonant frequency of the air chamber. The interaction of compression and expansion waves between the working and air chambers now generates a periodic oscillatory movement of air from the air chamber to the working chamber to participate in the combustion reaction of the fuel.
Of course, all the air in the room is not introduced at once, as this would adversely affect the combustion process. Rather, the air is released in a controlled manner through the critical gap in order to react with the fuel for a certain period of time in a manner dependent on the proportions adapted to the combustion process itself. The transfer of air from the air chamber to the working chamber proceeds like a pumping action even when the pressure in the working chamber increases and the overall average pressure in the working chamber is higher than that average pressure in the air chamber. It should be noted that The essence of the interaction process is that the rebound of the shock wave from the gap region causes a temporary and localized pressure drop in the vicinity of the gap, which allows the expansion of the Helmholtz oscillation from the air chamber into the combustion zone. Therefore, the air movement continues throughout the combustion stroke and causes an appropriate working chamber pressure reduction so that after the piston has moved a sufficient distance from the closed end of the cylinder, the air movement will stop expanding. It is therefore not simply dependent on the air capacity of the air chamber to be discharged into the working chamber.

As shown in Figure 12f, the movement of air from the air chamber to the working chamber occurs when the working chamber expands due to the movement of the piston while the air chamber is still oscillating at the Helmholtz resonance frequency _B. Proceed to. As hot air from chamber 38 enters the combustion zone along the outer cylinder wall and expands centrally into the upper region of the working chamber of the cylinder, a reaction between the air and the fuel is observed. be done.

Therefore, from the moment ignition proceeds, air is constantly supplied to the combustion zone due to the Helmholtz resonance in the air chamber and the interaction of the shock/expansion waves in the vicinity of the gap. This improves the combustion stroke so that all of the charged fuel reacts, since the device of the invention allows a long combustion time for all of the fuel elements to react. As is well known, oxidation of fuel (combustion) is a chemical process that breaks the bonds between hydrocarbon components and produces intermediate compounds with different bond strengths. By providing additional time for combustion with additional highly activated oxygen in the combustion zone, unstable compounds that require additional time for reaction can react with available oxygen. can. Of course, the flame tip in the working chamber never actually penetrates the gap and enters the air chamber.
This is because the gap is constructed to prevent any flame front from reaching the air chamber.

If the internal combustion engine operates in self-ignition mode,
Ignition timing is determined by the pressure and temperature within the working chamber, as is well known. However, according to the invention, the autoignition process is activated due to the presence of radicals pre-seeded by the filling as well as additional radicals supplied from the air chamber by the Helmholtz resonance effect. It is thought that this occurs at many points indoors. Ignition timing is controlled by constructing the cap of a material with a temperature coefficient that facilitates self-ignition at low compression ratios and optimizes the temperature of the cap for the fuel being combusted and the compression ratio of the internal combustion engine. It is possible. Regarding this,
It will be discussed in more detail later when the process for controlling the timing of autoignition is described.

In FIG. 12g, the piston approaches the BDC position and a sound tube resonance is generated within the working chamber as described above. The reaction of the remaining fuel near the cap continues and further heating of the cap occurs due to radiant heat.

In FIG. 12h, the exhaust valve is opened and the combustion products immediately begin to be exhausted from the combustion chamber with a decrease in pressure in the working chamber. The oxygen and radicals remaining in the air chamber begin to expand across the gap (with a delay if the gap is configured to create a flow between the air chamber and the working chamber at this point); It is then capable of reacting with hydrocarbon compounds within the working chamber to combine with exhaust, react with remaining fuel, or provide a thermal reactor for exhaust exhaust.

During the exhaust stroke, degassing of non-combustible hydrocarbons and vaporized oil in the ring and clearance gaps occurs, and the presence of these compounds is likely to contribute significantly to the amount of non-combustible hydrocarbons in the exhaust gas in standard conventional internal combustion engines. Are known. In this invention, the degassing of hydrocarbons from the area of the gap and the ring is extended only into the air chamber adjacent to the gap. (As shown in FIG. 2, the length of the gap surface 50 between the bottom of the air chamber 38 and the top of the first ring seal is set as long as possible to minimize the volume of the gap area above the ring seal groove. On the other hand, the degassing of hydrocarbons and evaporated oil into the air chamber generates hydrocarbon radicals, which further contribute to the reaction between the oxygen obtained from the air chamber and the fuel in the working chamber. Some of the radicals generated by the venting of the interstitial region remain in the air chamber for later use. Therefore, the heated air chamber 38 on the underside of the cap 32
acts as a reactor area for the fuel molecules degassed from the piston clearance and ring gap, thereby reducing or eliminating the amount of UHC from the source in the exhaust stream. By the way,
It should be noted that the bulk of the interstitial area is dimensionally too small to allow the generation of radicals within it, which makes the availability of a larger and closer heated air chamber volume V _B provides significant benefits in reducing the emission UHC generated by the degassing process.

As the exhaust stroke progresses, the reactions occurring in the air chamber further cause expansion and agitation of the gas within this air chamber, and as the exhaust stroke progresses (see Figures 12i and 12j), the Produces an acceleration of the cylinder of gas towards the closed end of the cylinder over the gap region and a subsequent rebound of the cylinder of gas towards the piston, thereby creating significant turbulence and mixing within the working chamber. . As shown in Figure 12k, in the middle of the exhaust stroke, when the flow across the gap region is reversed, the acceleration of the piston causes an instantaneous inflow of combustion products into the air chamber. However, near the end of the exhaust stroke in FIG. 12l, the deceleration of the piston and the low pressure in the working chamber cause a final depressurization of the air chamber and complete venting of the interstitial region of the piston.

The final reaction of the interstitial steam in the air chamber then produces various hydrocarbon radicals, which can be characterized as "post-flame" radicals depending on the exhaust flow produced during the combustion process. is characterized as a "pre-flame" radical. Of course, the pre-flame radicals are clearly somewhat different in chemical composition from the post-flame radicals. This is because these radicals do not take part in the high-temperature and high-pressure combustion reactions of the charged fuel, but arise only from the cracks of the low-pressure and low-temperature fuel molecules present in the air chamber during the exhaust stroke. Therefore, the remainder of the post-flame radicals from the combustion products in the exhaust gas as well as the pre-flame radicals from the interstitial degassing are present in the chamber as a highly reactive mixture along with the air in the chamber 38.

Upon completion of the exhaust stroke, the exhaust valve is closed and the intake valve is opened (possibly with appropriate overlap to suit the requirements of a given internal combustion engine). The piston begins to move away from the closed end of the cylinder bore to begin the next intake of air into the working chamber. As the piston accelerates downward, as shown in Figure 12m, venting of air and radicals into the air chamber occurs due to rapid piston movement and reduced pressure within the working chamber. This generates a species of inhaled air containing highly reactive radical mixtures in the air chamber. Since the air in the working chamber is much cooler than the air in the air chamber, the hot radicals are "cooled" and diluted. Due to this. The reaction of the radicals within the air chamber is further substantially delayed until they are reactivated during the next compression and combustion stroke.

In Figure 12n, the piston is nearing the end of its intake stroke, but fuel has not yet been introduced into the working chamber. 12o and 12p, fuel is added to the intake port area of the working chamber (for a fuel-breathing internal combustion engine) and stratified in the desired axial direction before compression begins to begin the next cycle. Generate a filling that has formed. In order to avoid contaminating the air chamber with fuel except in very small quantities (sufficient for combustion), various procedures as described above are used to obtain an axially layered packing. can be used.

When the next compression stroke begins (FIG. 12a) and ignition begins (FIG. 12d), the charge is a mixture of fresh fuel and radicals. This radical is generated during heating and compression of fresh fuel.
Post-flame radicals and pre-flame radicals are seeded from the previous compression cycle and the degassing of the fuel and air gap at the end of the previous cycle. Ignition is therefore sharply increased, whereby the autoignition pressure/temperature range is reduced according to known principles, as illustrated in FIG. 14. In FIG. 14, a typical compression ignition autoignition region 128 is shown in relation to the pressure and temperature within the working chamber 16. The region 130 is a self-ignition region where radicals increase, and the seeding effect of radicals is a self-ignition region and the Russian physicist N. N. It shows how this affects the phenomenon extensively investigated by NNSeminov. The shape of radical enrichment region 130 is sometimes referred to as a "Seminov Peninsula" in nature. Region 132 to the lower left of region 130 requires a spark or high temperature source to initiate combustion in a typical internal combustion engine. This is because ignition of the charge does not occur spontaneously. Therefore, the pressure within the working chamber is at least in the radical increase autoignition region 130.
The temperature of the charge is determined only by whether ignition starts spontaneously or only by the induction of a spark, a high temperature source, generally above the horizontal leg of can recognize the 2
By controlling the temperature of the charge by adjusting the amount of secondary air and by maintaining the temperature of the cap 32 below the detonation temperature, the combustion cycle of the present invention is selective in its self-ignition or spark-ignition nature. It is controlled so that it is carried out. According to the invention, the temperature of the charge is close to the radical increase autoignition temperature with respect to the extreme pre-combustion temperature of the charge, which is varied by varying the air-fuel ratio through the control of the secondary air entering the working chamber. It is carried out at the temperature of the filling of the working chamber.
In this way, a slight increase or decrease in the charge temperature within the autoignition region (region 130 or region 132) or outside this region is achieved and the combustion cycle is selectively carried out in spark ignition or autoignition mode. be done.

Of course, in autoignition mode, the cycle is a low compression ratio (5-9:1) fuel intake cycle. Due to the controlled supply of Helmholtz resonant air from the air chamber to the combustion zone 16 throughout the combustion stroke and the long combustion time provided by the piston and combustion chamber geometry, violent detonations and knocks are avoided even with gasoline fuels. It is believed that the radical type (pre-flame) imparted to the working chamber also enhances the whole process and allows close control of ignition on both sides of the radical build-up region.

In the case of fuel injection, such as the compression ignition internal combustion engine shown in FIG.
Optimum ignition timing is believed to be ensured by selecting the cap 32 with the thermal coefficient and construction that produces the highest power for that cycle when implemented in the 1st cycle. That is, the material of the cap and the construction of the cap, depending on the fuel and compression ratio used in the internal combustion engine, create a cap temperature that produces self-ignition timing that takes full advantage of the maximum power output of the internal combustion engine. selected to have a thermal coefficient of

Only preferred embodiments of the invention have been described herein, and those skilled in the art may make various modifications to the described structure or process without departing from the concept of the invention as defined in the claims that follow. It is clear that this can be done.