JPS6124528B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reciprocating piston internal combustion engine, in particular to such an engine with a built-in supercharger.

The trend in engine design has always been to achieve higher horsepower for a given engine displacement, size and weight. At the same time, fuel efficiency becomes an important consideration in many applications. As is well known to those skilled in the art, two-stroke engines produce significantly more horsepower per cubic ^inch of displacement at a given rpm than naturally aspirated four-stroke engines of any production method. However, two-stroke engines are substantially less efficient engines. A supercharged four-stroke engine is a compromise that produces more power per unit weight than a regular four-stroke engine and has better fuel economy than a two-stroke engine. However, superchargers are generally expensive and have only practical application in the racing car field. Therefore, the main object of the present invention is to
The object is to provide a relatively simple and effective supercharger for a four-stroke engine.

The internal combustion engine according to the invention uses a stepped piston with a first piston part that acts in the usual manner as a movable wall of the combustion chamber. The stepped or enlarged diameter portions operate within adjacent axially aligned bores of the cylinder. The stepped portion of the piston or the compressor piston is provided with ports and these ports allow the fuel-air mixture to be transferred from the engine crankcase to the engine with the stepped portion of the piston and the bore within which this piston acts. A check valve is provided within the compressor section to allow flow in one direction. This configuration results in two suction strokes and two compression strokes of the compressor per four combustion cycles. The air-fuel mixture entering the compressor on the downstroke of the piston is captured by these check valves, compressed on the upstroke, and delivered into a bypass accumulator manifold connected to the intake valve for the main cylinder. Thus, the compression system of the present invention effectively delivers two charges of air into the bypass manifold per combustion cycle to provide a simple, high performance two-stroke engine that produces high horsepower for a given weight or displacement. It acts as a supercharger.

Embodiments of the four-stroke internal combustion engine of the present invention will be described below with reference to the accompanying drawings.

A preferred embodiment of the engine of the invention having a single cylinder has an enlarged stepped section or compressor piston 12 at its lower end, as shown in FIGS. 1, 2, 3 and 4. The engine piston 10 is provided with an engine piston 10. The engine piston 10 is connected to the crankshaft 14
are all driven via a connecting rod 16 and piston pin 17 of conventional construction. The upper part of the engine piston 10 is located in the combustion chamber cylinder 1.
8 reciprocating within the upper and lower sealing piston rings 1
Grooves are formed to receive the holes 9 and 19a. The annular compression piston 12 of the engine piston 10 operates in a cylinder mounted on a portion of the engine piston 10, preferably formed integrally with this portion, and having an enlarged area bounded by walls 20. engine piston 1
The compression piston 12 of the engine 0 is provided with a passage 22 for conveying the fuel-air mixture from the crankcase 23 of the engine into the compressor chamber. This compressor chamber is formed by the cylinder wall 20, the compression piston 12 of the engine piston 10, and an annular shoulder 25 at the lower end of the cylinder stepped section or cylinder wall 18. Passage 2 formed through the annular shoulder 25
6 is closed by a one-way check valve 27. At least one set of passageways 26 and check valves 27 are provided;
A plurality of sets may be provided approximately equally spaced from one another around shoulder 25 depending on the size and performance characteristics of the engine.

Passage 26 provides communication between the combustion chamber and the manifold. This manifold consists of an annular collection chamber 28 that adjoins around the shoulder 25 and opens into and communicates with an accumulator manifold 29. One end of the Honifold 29 is connected to the intake valve 30 in the combustion chamber of this engine.
communicate periodically via the Valve 30 may be of any desired shape. In many cases, valve 30 may be configured as a rotary valve as shown to take advantage of the known advantages of such valves. Poppet and other types of valves may be used depending on the conditions of use and the designer's preference. The exhaust from the engine is also controlled by a rotary valve 30 shown in FIG. 4 during part of the exhaust cycle, as will be described in more detail below. A manifold 29 and a rotary valve 30 receive a charge of air from the compressor chamber during the exhaust and compression strokes and provide two charges of air to the combustion chamber during the intake stroke of each engine cycle. Two charging devices are constructed.

Combustion air, usually in the form of a fuel-air mixture, is passed through passage 32 via a carburetor or the like (not shown).
Send via . A check valve 34 is used where appropriate, but preferably to prevent backflow to the vaporizer. Alternatively, a fuel injector (not shown) may be used to inject fuel into the combustion chamber, as is well known for diesel engines, for example.

The preferred construction for the portion of the engine block forming collection chamber 28 is shown in detail in FIG. The combustion chamber cylinder is formed as part of the engine block and is supported by a shoulder 25 from its outer wall 36. In this way, an annular hollow cylinder portion 38 with an open top is formed. A plurality of passages 26 are formed in the shoulder portion 25 . The check valve 27 is an annular plate attached to the bottom of the hollow cylinder 28. Check valve 2
A particularly preferred shape of 7 comprises an upper disk 27a made of rubber or the like and a lower disk 17b made of a thin beryllium alloy spring material.

A check valve 27 consisting of a check valve 24, a shoulder 25, a passage 26, and an upper disk 27a and a lower disk 27b allows air to flow from the crankcase 23 into the compressor chamber during the intake stroke and the power stroke. A first charging device for charging air is configured.

The inner periphery of the check valve 27 is clamped to the shoulder 25 by a sleeve 40, and in particular by a reduced diameter cylindrical end 41 which slidably fits into its cylinder 18. The cylinder end 41 terminates at its upper end in a radial shoulder 42 spanning an enlarged diameter cylinder 43, which fits slidably within the outer wall 36 and extends towards an engine head 48 equipped with a valve. Cylinder head gasket 46
are associated with a sealing action.

Since the sleeve 40 is sealed at each end, the sleeve 40 divides the cavity 38 into two separate cavities, a collection chamber 28 and an annular cavity 50.
The cavity 50 is connected to a source of circulating cooling water.

FIG. 6 illustrates the operation of the engine over the entire combustion cycle. To illustrate the operation of the compressor, the timing diagram of this engine from top dead center to top dead center is shown at 180 degrees instead of the usual 360 degrees. That is, the combustion cycle consists of an engine intake stroke, a compression stroke (quarter), a power stroke (quarter), and an exhaust stroke (quarter), which generally occur in the first quarter of the diagram.

The preferred embodiment of the invention in combination with the diagram of FIG. 6 is a high performance engine with substantial valve overlap. In particular, the intake valve opens at 42 degrees before top dead center and closes at 70 degrees after bottom dead center, but the exhaust valve opens at 64 degrees before bottom dead center on the power stroke and does not close until 36 degrees after top dead center on the exhaust stroke. .

The operation of the compressor portion of the present invention is also shown in FIG. Check valves for compressors are controlled solely by gas forces, inertia, and piston motion on these valves. That is, these check valves open and close substantially at the top dead center and bottom dead center positions of the piston.

It is thus clear that the compressor section of the engine charges the combustion chamber twice with the combustion mixture for each combustion stroke. The fuel-gas mixture within crankcase 23 is pumped from a carburetor (not shown) at near atmospheric pressure (14.7 PSIA) through passage 32 and through check valve 34. However, as mentioned above, the fuel may be delivered separately to the combustion chamber.

If a fuel-air mixture at atmospheric pressure is to be sent to the crankcase, the compressor section is
Fill with 14.7PSIA combustion mixture. Two compressor charges are sent to the combustion chamber on each engine intake stroke. In other words, the theoretical charging pressure is given by the following equation, assuming that there is no overlap of valves.

P _E =2×VE/V×14.7PSIA In this equation, P _E is the engine combustion chamber pressure, V _E is the engine combustion chamber volume, and V _e is the compressor volume. It is clear that supercharging will occur for any engine geometry in which the compressor volume is greater than half the combustion chamber volume. The lower limit of the actual engine is approximately 3/3 of the combustion chamber volume.
The compressor volume is equal to 4.

In the illustrated preferred embodiment, the engine combustion chamber and compressor volumes are equal to provide a theoretical (assuming no valve overlap) charge pressure of approximately 29 PSIA. Although in practice a somewhat lower charge pressure than this could be expected with valve timing as shown in FIG. 5, the relatively high valve overlap chosen for this example (indicated by B for discharge in FIG. 6) However, a substantial amount of supercharging effect can be obtained.

7, 8 and 9 diagrammatically illustrate a preferred multi-cylinder embodiment of the present invention. To minimize the size and weight of such engines, a minimum spacing between adjacent combustion cylinders may be utilized.

For this purpose, as shown in FIG. 9, the compressor piston 12a is elongated and the engine piston 12a is
It has a width equal to the diameter of 0a and extends in the lateral direction of the engine. That is, as shown in FIG. 7, engine pistons 10a adjacent to each other can be moved in the direction along the row of cylinders without requiring any additional spacing to receive their stepped portions, compressor pistons 12a. can be adjacent to As shown in FIG.
It is preferable to provide it above 2a. A manifold is provided which can be adapted to the overall geometry of the engine in any conventional manner to provide communication between the collection chamber 28a and the combustion chamber. In some applications it may be advantageous to provide a relief in the cylindrical body of the main part of the engine piston directly above the compression piston 17a so that a single collection chamber 28a can be used.

FIG. 10 shows a preferred sealing structure for the piston 12 or piston 12a of the compressor. The piston 12 is formed with a circumferential groove 50 with a stepped section 51 of reduced radial depth. O consisting of any suitable rubber or rubber-like material
Ring 52 is fitted within groove 50 and resiliently biases seal 53, which is a continuous ribbon of rectangular cross section made of polytetrafluoroethylene or the like.

The operation of this engine will be described below.

The operating cycle of this engine will be reconsidered with reference to Figures 1 to 4. In Figure 1, the engine piston 10
is in its lowest position just before starting the compression stroke. During the previous 180° rotation of the crankshaft 14,
The engine piston 10 moves downward from the top dead center position and the check valve 24 opens to allow air or a fuel-air mixture to flow from the crankcase 23 into the compressor. During this same period of time, the inlet portion of the rotary valve 30 opens and the previously charged air that entered the manifold 29 is sucked into the cylinder 18. In FIG. 2, the crankshaft 14 has been rotated 90 degrees from the position of FIG. Fuel compressed during compression stroke 1
The air mixture is delivered to manifold 29 via valve 27, which is now open. In FIG. 3, the charge in the main cylinder is ignited and the engine piston 10 begins its downward power stroke, opening the check valve 24 to direct a new charge of air or fuel-air mixture into the compressor. Enter. FIG. 4 shows the engine piston 10 at the top dead center position at the end of the exhaust stroke of the cycle, which is also the end of the second compression stroke. That is, it is clear that there are two compression strokes of the compressor piston in each combustion cycle of this engine. It is not believed that there is a critical ratio between the compressor volume and the combustion chamber volume of this engine. The relative volume may be changed as necessary to produce the desired degree of supercharging. 1:1 of chamber volume
A volume ratio of , and thus a compression ratio of 2:1, is preferred.

Manifold volume primarily affects operation because it determines the time required for this volume to reach the same steady state operating pressure. That is, if the manifold volume is relatively small, the same operating pressure will be reached in fewer strokes than if, for example, the manifold volume was substantially larger than the volume of the compression cylinder. However, the end result is the same for any given engine since the same pressure is always reached regardless of manifold size or engine speed. The manifold volume should be similar in size to the compressor and combustion chamber.

As will be apparent to those skilled in the art, many modifications and variations of this invention are possible. For example, as briefly mentioned above, the supercharger of the present invention can be used in fuel-injected gasoline or diesel engines. Although a rotary valve arrangement is illustrated, it will be appreciated that other known valve structures may be used instead. Similarly, engine timing, supercharging, and many other features of the overall engine may vary from the above description of the preferred embodiment.

Although the present invention has been described above in detail with reference to its embodiments, it goes without saying that the present invention can be modified in various ways without departing from its spirit.

[Brief explanation of the drawing]

FIGS. 1, 2, 3, and 4 are axial sectional views partially showing the intake, compression, power, and exhaust strokes of a preferred embodiment of the engine of the present invention, respectively. FIG. 5 is a partial axial sectional view showing an enlarged preferred structure of the engine block of the engine shown in FIGS. 1 to 4, and FIG. 6 is a timing line showing the operation of the engine shown in FIGS. 1 to 4. It is a diagram. FIG. 7 is a partial front view showing a part of the piston cylinder structure suitable for a multi-cylinder engine according to another embodiment of the present invention in longitudinal section, and FIG. 8 is a partial cross section of the piston cylinder shown in FIG. 7. FIG. 9 is a perspective view of the piston of FIGS. 7 and 8, and FIG. 10 is a partial cross-sectional view of a preferred seal for the compressor of the engine of the invention. 10... Engine piston, 12... Piston stepped portion (compressor piston), 18... Cylinder wall, 20... Cylinder wall, 23... Crank case, 24... Check valve, 27... Check valve .

Claims (1)

[Scope of Claims] A combustion chamber formed by a cylinder and an engine piston mounted to reciprocate within the cylinder, and a crankcase, wherein the engine piston provides exhaust, intake, and compression for each engine cycle. and operates on separate and different strokes of power, the exhaust stroke and the compression stroke occurring at separate times in one direction of the engine piston, and the intake stroke and the power stroke occurring during the 4 caused to occur during separate strokes of the engine piston in the other direction.
In a cycle internal combustion engine, a compressor comprising: (a) a compression piston attached to the engine piston; and a compressor cylinder that receives the compression piston in a sealed state and forms a compressor chamber together with the compression piston, and (b) the engine. a first charging device for charging air from the crankcase into the compressor chamber during each of the intake strokes and power strokes of the piston; a second charge device for receiving a charge of air from the compressor chamber and providing two charges of air to the combustion chamber substantially during the intake stroke of each engine cycle; by providing the chamber with a volume greater than half the volume of the combustion chamber;
A four-stroke internal combustion engine, characterized in that the compressor forms a supercharger and delivers air to the combustion chamber at a higher pressure than the air delivered to the supercharger. 2. The four-stroke internal combustion engine according to claim 1, wherein the compressor chamber and the combustion chamber have substantially equal volumes. 3. The engine piston according to claim 1, wherein the engine piston has a circular cross section and the compressor piston has a width substantially equal to the diameter of the engine piston and a length greater than this width. 4-stroke internal combustion engine. 4. The engine piston according to claim 2, wherein the engine piston has a circular cross section and the compressor piston has a width substantially equal to the diameter of the engine piston and a length greater than this width. 4-stroke internal combustion engine. 5. A first charging device that charges air into the compressor chamber is provided on the compressor piston and connects between the crankcase and the compressor chamber, from the crankcase to the compressor chamber. A four-stroke internal combustion engine according to claim 1, further comprising a check valve that allows flow to flow in one direction. 6. A first charging device that charges air into the compressor chamber is provided on the compressor piston, and connects the crankcase and the compressor chamber between the crankcase and the compressor chamber. 3. The four-stroke internal combustion engine according to claim 2, further comprising a check valve that allows flow to flow in one direction. 7 A first charging device that charges air into the compressor chamber is provided on the compressor piston, and connects the crankcase and the compressor chamber between the crankcase and the compressor chamber. 4. The four-stroke internal combustion engine according to claim 3, further comprising a check valve that allows flow to flow in one direction. 8 A first charging device that charges air into the compressor chamber is provided on the compressor piston, and connects the crankcase and the compressor chamber between the crankcase and the compressor chamber. 5. The four-stroke internal combustion engine according to claim 4, further comprising a check valve that allows flow to flow in one direction.