JP5227235B2 - engine - Google Patents

Description

  In the present invention, an intake stroke, a compression / ignition stroke, an expansion stroke, and an exhaust stroke are performed in this order, and apart from these four strokes, a rest stroke in which the piston is reciprocated without combustion is performed before the compression / ignition stroke. The present invention relates to an engine that performs an increased stroke cycle operation in which two or more are added.

  As a conventional engine, in one cycle including four strokes of an intake stroke, a compression / ignition stroke, an expansion stroke, and an exhaust stroke, apart from these four strokes, a rest stroke in which the piston is reciprocated without combustion is 1 One that performs an increased stroke cycle operation in which one or more are added is known (see, for example, Patent Document 1). In an engine that performs this increased stroke cycle operation, the intake valve is in the open state and the exhaust valve is in the closed state. Thus, a pause compression stroke in which the inside of the cylinder is compressed as the piston rises while the exhaust valve is closed, and a pause expansion in which the piston is pushed back from the top dead center by the pressure increase in the cylinder accompanying the compression of the air-fuel mixture in the pause compression stroke. When the intake valve is closed and the exhaust valve is closed, the compression / ignition stroke is performed to ignite the air-fuel mixture near the top dead center while compressing the inside of the cylinder as the piston rises. The expansion stroke (combustion stroke) in which the piston is pushed down by the expansion of the intake valve, the intake valve is closed, and the exhaust valve is opened. An exhaust stroke for exhausting to the outside through the exhaust passage with the combustion gases to increase the piston is performed in this order, one cycle is constituted with these six-stroke. And, the idle compression stroke and the idle expansion stroke performed between the intake stroke and the compression / ignition stroke function as a pause stroke in which the piston reciprocates without combustion, which is called such a pause stroke. If an increase stroke cycle operation with an added stroke is added, for example, a 6 stroke cycle operation as described above is performed, a normal operation (ie, a four stroke cycle operation in which one cycle is operated without adding a pause stroke) is performed. In comparison, the shaft output can be reduced by the addition of a pause process in which no shaft output is generated in one cycle, which is advantageous in a situation where there is a demand to reduce the output at the same rotational speed.

JP 2004-116305 A

  However, the above-described conventional engine has the following problems to be solved. First, in a conventional engine in an increased stroke cycle operation, a resting stroke is performed in a state where a sufficient air-fuel mixture is sucked into the cylinder (that is, both the exhaust valve and the intake valve are closed). Since the piston is reciprocated), there is a problem that the heat loss in the resting stroke (that is, the resting compression stroke and the resting expansion stroke) becomes large, and the operating efficiency of the engine is lowered.

  Second, the compression / ignition stroke is performed following the rest stroke, and the intake valve and the exhaust valve are held closed during these strokes, so that the flow of the air-fuel mixture in the cylinder during the compression ignition is performed. However, there is a problem that the combustion efficiency is deteriorated.

  An object of the present invention is to provide an engine capable of increasing the operation efficiency by suppressing heat loss in a resting stroke in an engine that performs an increased stroke cycle operation.

  Another object of the present invention is to provide an engine capable of improving combustion efficiency by increasing the flow of air in a cylinder during compression ignition.

An engine according to claim 1 of the present invention includes an intake valve disposed on an intake side for sucking an air-fuel mixture into a cylinder, an exhaust valve disposed on an exhaust side for discharging combustion gas in the cylinder , a piston which reciprocates between a top dead center and bottom dead center, the opening and closing of the intake valve and the exhaust valve caused by the reciprocating motion of the piston, in one cycle, the intake stroke, a compression-ignition stroke, performs expansion stroke and an exhaust stroke in this order, and add one or more between the resting stroke from these four-stroke reciprocating the piston is without separate combustion the intake stroke and the compression and ignition strokes An engine that performs an increased stroke cycle operation,
In the intake stroke, the intake valve that is open is closed in an angle range of a crank angle of 20 to 90 degrees on the near side of the bottom dead center of the intake stroke, and in the rest stroke, the intake valve and the exhaust valve are closed. The piston is reciprocated with the valve closed, and in the final resting stroke before the compression / ignition stroke, the piston moves from the top dead center to the bottom dead center, and then at the bottom dead center before the rest stroke. The intake valve and / or the exhaust valve is opened .

Further, in the engine according to claim 2 of the present invention, in the angle range of the crank angle of 20 to 90 degrees on the near side of the bottom dead center of the rear rest stroke in the last rest stroke before the compression / ignition stroke. The intake valve and / or the exhaust valve is opened.

According to the engine of the first aspect of the present invention, the intake valve is closed earlier than the bottom dead center before the bottom dead center of the intake stroke. Therefore, when the intake valve is closed, sufficient air-fuel mixture is sucked into the cylinder. In addition, the pressure of the air-fuel mixture generated in the cylinder in the pre-pause stroke (pause compression stroke) and the post-pause stroke (pause expansion stroke) of the pause stroke following the intake stroke is suppressed, thereby reducing heat loss in the pause stroke. Can be suppressed. Further, since the intake amount of the air-fuel mixture into the cylinder during the intake stroke is reduced, the engine output can be reduced. Further, since the intake valve is closed in an angle range of a crank angle of 20 to 90 degrees on the near side of the bottom dead center of the intake stroke, the intake amount of the air-fuel mixture sucked into the cylinder is reduced, and the intake air amount of this air-fuel mixture is reduced. It is possible to suppress the increase in the pressure of the air-fuel mixture in the cylinder during the resting process and to suppress heat loss during the resting process. Note that the intake amount of the air-fuel mixture sucked into the cylinder increases (or decreases) when the intake valve closes toward (or moves away from) the bottom dead center, and the intake stroke is adjusted by adjusting this time. The amount of inhalation can be adjusted. In addition, since the intake valve is opened before the bottom dead center in the post-pause stroke (pause expansion stroke) in the final pause stroke before the compression / ignition stroke, the air-fuel mixture is re-inhaled from the intake side, and this intake air-fuel mixture Thus, the flow of the air-fuel mixture in the cylinder is promoted, and the combustion efficiency can be increased by improving the fluidity. Instead of opening the intake valve or in addition to the intake valve, the exhaust valve may be opened. When the exhaust valve is opened, the flow of the air-fuel mixture in the cylinder is promoted by the exhaust gas flowing from the exhaust side. The

In the engine according to claim 2 of the present invention , the intake valve (and / or the exhaust valve) is within an angle range of a crank angle of 20 to 90 degrees before the bottom dead center of the post-stop stroke in the final stop stroke. ) Is opened, the air-fuel mixture (and / or exhaust gas) flows into the cylinder from the suction side (and / or exhaust side), and the flow of the air-fuel mixture in the cylinder by the inflowing air-fuel mixture (and / or exhaust gas) Is increased. Note that the opening timing of the intake valve (and / or the exhaust valve) is in an angle range from an angle equal to the crank angle of the valve closing timing closed near the bottom dead center of the intake stroke to 1.5 times this angle. The crank angle is desirable.

1 is a cross-sectional view schematically showing a part of a first embodiment of an engine according to the present invention. 2A is an operation diagram of the engine of FIG. 1, FIG. 2B is an opening / closing timing chart showing opening / closing timings of the intake valve and the exhaust valve, and FIG. 2C shows a relationship between the crank angle and the piston position. Illustration. 3A is an operation diagram of the engine of the second embodiment, FIG. 3B is an opening / closing timing chart showing opening / closing timings of the intake valve and the exhaust valve, and FIG. 3C is a graph showing the crank angle and the piston position. Explanatory drawing which shows a relationship. 4A is an operation diagram of the engine of the third embodiment, FIG. 4B is an open / close timing chart showing the open / close timing of the intake valve and the exhaust valve, and FIG. 4C is a graph showing the crank angle and the piston position. Explanatory drawing which shows a relationship. FIG. 5A is an operation diagram of the engine of the fourth embodiment, FIG. 5B is an opening / closing timing chart showing opening / closing timings of the intake valve and the exhaust valve, and FIG. 5C is a graph showing the crank angle and the piston position. Explanatory drawing which shows a relationship. 6A is an operation diagram of the engine of the fifth embodiment, FIG. 6B is an open / close timing chart showing the open / close timing of the intake valve and the exhaust valve, and FIG. 6C is a graph showing the crank angle and the piston position. Explanatory drawing which shows a relationship. 7A is an operation diagram of the engine of the sixth embodiment, FIG. 7B is an opening / closing timing chart showing opening / closing timings of the intake valve and the exhaust valve, and FIG. 7C is a graph showing the crank angle and the piston position. Explanatory drawing which shows a relationship.

  Hereinafter, an embodiment of an engine according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view schematically showing a part of a first embodiment of an engine according to the present invention, FIG. 2 (a) is an operation diagram of the engine of FIG. 1, and FIG. 1 (b) is an intake valve. 4 is an open / close timing chart showing the open / close timing of the exhaust valve, and (c) is an explanatory diagram showing the relationship between the crank angle and the piston position.

  In FIG. 1, the illustrated engine 1 includes an engine body 6 that defines a cylinder 2. A piston 6 is reciprocally mounted in the cylinder 2, and combustion is performed by the inner peripheral surface of the cylinder 2 and the top surface of the piston 6. Chamber 8 is defined. An intake passage 10 is provided on the intake side of the combustion chamber 10, and an intake valve 12 is disposed in the intake passage 10 so as to be freely opened and closed. Through this intake passage 10, an air-fuel mixture (fuel and air are mixed). Is supplied to the combustion chamber 8. Further, an exhaust passage 14 is provided on the exhaust side of the combustion chamber 10, and an exhaust valve 16 is disposed in the exhaust passage 14 so as to be freely opened and closed. The combustion exhaust gas in the combustion chamber 8 is exhausted through the exhaust passage 14. Is done.

  One end (front end) of a connecting rod 18 is swingably connected to the piston 6, and the other end (base end) of the connecting rod 18 is rotatably connected to the crankshaft 20. The reciprocating motion is transmitted to the crankshaft 20 through the connecting rod 18, and the crankshaft 20 is rotationally driven in a predetermined direction. Such a configuration is the same as that of an engine known per se.

  The engine 1 is provided with a valve mechanism 22 for opening and closing the intake valve 12 and the exhaust valve 16 as will be described later. The valve mechanism 22 is, for example, a cam mechanism, an electromagnetic actuator mechanism or a hydraulic actuator mechanism. The valve timing variable mechanism 24 may be provided in association with the valve operating mechanism 22. This variable valve timing mechanism 24 changes the rotation of the cam means when using the cam mechanism, changes the phase of the periodic operation of the actuator when using the electric actuator mechanism or the hydraulic actuator mechanism, and so on. The opening / closing timing of the intake valve 12 and the exhaust valve 16 is adjusted.

  In such an engine 1, for example, natural gas (for example, city gas) as a fuel gas is mixed with the air sucked in the intake passage 10 to form an air-fuel mixture, and the mixture thus formed Gas is supplied to the combustion chamber 8. For example, gasoline may be used as the fuel.

  Referring also to FIG. 2, in this engine 1, the intake valve 12 and the exhaust valve 16 are opened and closed as follows by the action of the valve mechanism 22. In this embodiment, an intake stroke is performed when the crank angle is 360 degrees (top dead center) to 540 degrees (bottom dead center). In this intake stroke, the intake valve 12 is opened and the exhaust valve is opened. The air-fuel mixture is supplied to the combustion chamber 8 through the intake passage 10 as the piston 6 descends.

  In this embodiment, a resting stroke is performed after the intake stroke, and a compression / ignition stroke is performed after the resting stroke. When the crank angle is from 540 degrees (bottom dead center) to 720 degrees (top dead center), a pause stroke before the pause stroke (pause compression stroke) is performed. Further, when the crank angle is from 720 degrees (top dead center) to 900 degrees, a resting stroke (resting expansion stroke) is performed after the resting stroke. In this resting stroke, the intake valve 12 and the exhaust valve 16 are kept closed, and the piston 6 is reciprocated without combustion of the air-fuel mixture sucked into the combustion chamber 8 (that is, in the previous resting stroke). The piston 6 is raised, and the piston 6 is lowered in the post-pause stroke).

  The compression / ignition stroke is performed after the rest stroke, and the compression / ignition stroke is performed when the crank angle is between 900 degrees (bottom dead center) and 1080 degrees (top dead center). In this compression / ignition stroke, the intake valve 12 and the exhaust valve 16 are kept closed, and the air-fuel mixture in the combustion chamber 8 is compressed by the rise of the piston 6, and at the time of compression, an ignition plug (not shown) is used. The mixture is sparked.

  Thereafter, an expansion stroke is performed when the crank angle is between 1080 degrees (top dead center) and 1260 degrees (bottom dead center). In this expansion stroke, the intake valve 12 and the exhaust valve 16 are kept closed, the piston 6 is pushed down by the combustion of the air-fuel mixture, the shaft output is obtained by pushing down the piston 6, and the pushing force from the piston 6 is reduced. Is transmitted to the crankshaft 20 through the connecting rod 18.

  An exhaust stroke is performed after the expansion stroke, and an exhaust stroke is performed when the crank angle is between 1260 degrees (bottom dead center) and 1420 degrees (top dead center). In this exhaust stroke, the intake valve 12 is kept closed, the exhaust valve 16 is kept open, and the combustion gas in the combustion chamber 8 is exhausted through the exhaust passage 14 as exhaust gas as the piston 6 moves upward (for example, In the atmosphere).

  In a normal engine, an intake stroke, a compression / ignition stroke, an expansion stroke, and an exhaust stroke are performed in this order, and these four strokes constitute one cycle of operation, and the cycles of the four strokes are repeated. Is called. On the other hand, in the engine 1 of this embodiment, in addition to the four strokes of a normal engine, that is, the intake stroke, the compression / ignition stroke, the expansion stroke, and the exhaust stroke, the intake stroke and the compression / ignition stroke are provided. Incremental process cycle operation in which a pause process (pre-stop process and post-stop process) is performed, and these six processes (the stop process is defined as two processes of a pre-stop process and a post-stop process) By performing the increase process operation in this way, the shaft output can be reduced by adding a pause process that does not generate shaft output within one cycle, and the output can be reduced at the same rotational speed. Can do.

  In the first embodiment, as shown in FIG. 2, the intake valve 12 is configured to close earlier than the bottom dead center near the bottom dead center (BDC) of the intake stroke. That is, the intake valve 12 is lowered from the top dead center (TDC) of the piston 6 to the bottom dead center (BDC) in the intake stroke, and is closed at, for example, a crank angle of 30 degrees before the bottom dead center of the intake stroke. The closed state is maintained until the end of the intake stroke, and is further maintained until the rest stroke, the compression / ignition stroke, the expansion stroke, and the exhaust stroke. The time when the intake valve 12 is closed (valve closing timing) is an angle range between 20 degrees and 90 degrees crank angle on the near side of the bottom dead center of the intake stroke (an angle between 450 degrees and 520 degrees in the timing chart of FIG. 2). Range) can be set to an appropriate angle.

  By setting the intake valve 12 to the closed state earlier than the bottom dead center of the intake stroke, the intake amount of the air-fuel mixture flowing into the cylinder 2 is reduced, and the rest stroke (pre-pause stroke and The pressure of the air-fuel mixture generated in the cylinder 2 in the post-pause stroke) is suppressed, and thereby heat loss in the pause stroke can be reduced.

  The timing at which the intake valve 12 is closed is related to the intake amount of the air-fuel mixture flowing into the combustion chamber 8. When the pressure is increased and the pressure suppression of the air-fuel mixture is increased and the closing timing is delayed (approaching the bottom dead center), the amount of reduction of the air-fuel mixture supplied to the combustion chamber 8 is reduced and the air-fuel mixture in the pause stroke is reduced. The pressure suppression becomes smaller.

  Next, a second embodiment of the engine according to the present invention will be described with reference to FIG. 3A is an operation diagram of the engine of the second embodiment, FIG. 3B is an opening / closing timing chart showing opening / closing timings of the intake valve and the exhaust valve, and FIG. 3C is a diagram illustrating the crank angle and the piston position. It is explanatory drawing which shows these relationships.

  In FIG. 3, in this embodiment, the configuration of the engine itself is substantially the same as that of the first embodiment described above, but the intake valve 12 is made slower than the bottom dead center near the bottom dead center (BDC) of the intake stroke. Configured to close. That is, the intake valve 12 descends from the top dead center (TDC) of the piston 6 to the bottom dead center (BDC) in the intake stroke and passes through the bottom dead center of the intake stroke. For example, the closed state is reached at a crank angle of 30 degrees, and this closed state is maintained until the end of the resting stroke, and further to the compression / ignition stroke, the expansion stroke, and the exhaust stroke. The time point when the intake valve 12 is closed (valve closing timing) is an angle range between the crank angle 20 degrees and 90 degrees of the pre-pause stroke on the rear side of the bottom dead center of the intake stroke (from 560 degrees in the timing chart of FIG. 3). The angle can be set to an appropriate angle of 630 degrees.

  By making the time when the intake valve 12 is closed to be later than the bottom dead center of the intake stroke, the air-fuel mixture flowing into the cylinder 2 is returned to the intake flow path 10 side by the rise of the piston 6, and the intake amount is reduced. Even in this way, the pressure of the air-fuel mixture generated in the cylinder 2 in the pause stroke (pre-pause stroke and post-pause stroke) is suppressed, and thereby heat loss in the pause stroke can be reduced.

  Even in this case, the closing timing of the intake valve 12 is related to the intake amount of the air-fuel mixture flowing into the combustion chamber 8, and the mixing supplied to the combustion chamber 8 is delayed when the closing timing is delayed (away from bottom dead center). When the amount of air decrease increases and the pressure suppression of the air-fuel mixture during the resting stroke increases and the closing timing is advanced (approaching bottom dead center), the amount of air-fuel mixture supplied to the combustion chamber 8 decreases. The pressure suppression of the air-fuel mixture in the rest process is reduced.

  In the first and second embodiments, one pause stroke is provided between the intake stroke and the compression / ignition stroke, but two or more pause strokes may be provided. In this case, when the closing timing of the intake valve 12 is advanced, the intake stroke comes before the bottom dead center of the intake stroke, but when the closing timing is delayed, it becomes the pre-pause stroke in the first pause stroke after the intake stroke. .

  Next, a third embodiment of the engine according to the present invention will be described with reference to FIG. 4A is an operation diagram of the engine of the third embodiment, FIG. 4B is an opening / closing timing chart showing opening / closing timings of the intake valve and the exhaust valve, and FIG. 4C is a crank angle and a piston position. It is explanatory drawing which shows the relationship.

  In FIG. 4, in this embodiment, the configuration of the engine itself is substantially the same as that of the first embodiment described above, but the intake valve 12 is moved earlier than the bottom dead center near the bottom dead center (BDC) of the intake stroke. The intake valve 12 is configured to close, and is configured to open the intake valve 12 near the bottom dead center of the post-pause stroke in the pause stroke.

  The intake valve 12 descends from the top dead center (TDC) of the piston 6 to the bottom dead center (BDC) during the intake stroke and closes at a crank angle of 30 degrees, for example, on the near side of the bottom dead center of the intake stroke. The closed state is maintained until the end of the intake stroke, and further maintained near the bottom dead center of the rest stroke after the rest stroke. When the intake valve 12 is closed, as in the first embodiment, an angle range between 20 degrees and 90 degrees on the front side of the bottom dead center of the intake stroke (from 450 degrees in the timing chart of FIG. 4). The angle can be set to an appropriate angle of 520 degrees.

  The intake valve 12 is also opened, for example, at a crank angle of 30 degrees before the bottom dead center (BDC) of the post-pause stroke in the pause stroke, and this open state is maintained until the end of the post-pause stroke. -It is kept closed in the ignition stroke, the expansion stroke, and the exhaust stroke.

  Thus, by making the closing timing of the intake valve 12 earlier than the bottom dead center of the intake stroke, the intake amount of the air-fuel mixture flowing into the cylinder 2 is reduced, and the inside of the cylinder 2 in the rest stroke following this intake stroke is reduced. The increase in the pressure of the air-fuel mixture can be suppressed, and thereby heat loss in the resting process can be suppressed to a small level. Further, by reducing the intake amount of the air-fuel mixture in this way, the air-fuel mixture can be re-inhaled through the intake passage 10 when the intake valve 12 is opened in the post-pause stroke, and the following effects are further achieved. can get.

  When the intake valve 12 is opened in the post-pause stroke, the air-fuel mixture is re-inhaled through the intake passage 10 as the piston 6 moves toward the bottom dead center, and the air-fuel mixture is re-inhaled and exists in the combustion chamber 8. The flow of the air-fuel mixture is promoted, the combustion improves the combustion of the air-fuel mixture, and the combustion efficiency can be increased. In particular, in the engine 1 that performs the compression / ignition stroke after the pause stroke, the piston 6 is reciprocated while the intake valve 12 and the exhaust valve 16 are closed during the pause stroke. However, when the intake valve 12 is temporarily opened and the air-fuel mixture is re-inhaled as described above, the air-fuel mixture in the combustion chamber 8 flows, and the combustion is caused by the flow. Efficiency can be improved.

  The time point at which the intake valve 12 is temporarily opened (valve opening timing) is an angle range between 20 degrees and 90 degrees before the bottom dead center of the post-pause stroke (from 810 degrees in the timing chart of FIG. 4). (The angle range of 880 degrees) can be set to an appropriate angle, and the opening timing of the intake valve 12 is equal to the crank angle of the closing timing close to the bottom dead center of the intake stroke. It is desirable to set an appropriate crank angle within an angle range of 1.5 times, and by setting the valve opening timing to such an angle, the amount of the air-fuel mixture that is reduced in the intake stroke is reduced. Can be replenished by releasing the intake valve 12.

  Next, a fourth embodiment of the engine according to the present invention will be described with reference to FIG. 5A is an operation diagram of the engine of the fourth embodiment, FIG. 5B is an opening / closing timing chart showing opening / closing timings of the intake valve and the exhaust valve, and FIG. 5C is a crank angle and a piston position. It is explanatory drawing which shows the relationship.

  In FIG. 5, in this embodiment, the configuration of the engine itself is substantially the same as that of the first embodiment described above, but the intake valve 12 is made slower than the bottom dead center near the bottom dead center (BDC) of the intake stroke. The intake valve 12 is configured to close, and is configured to open the intake valve 12 near the bottom dead center of the post-pause stroke in the pause stroke.

  As in the second embodiment, the intake valve 12 descends from the top dead center (TDC) of the piston 6 to the bottom dead center (BDC) during the intake stroke, and is suspended before the bottom dead center of the intake stroke. For example, the stroke is closed at a crank angle of 30 degrees in the stroke, and this closed state is maintained near the bottom dead center of the pressure pause stroke. The time point when the intake valve 12 is closed is an angle range between 20 degrees and 90 degrees crank angle (an angle range between 560 degrees and 630 degrees in the timing chart of FIG. 5) in the pre-pause stroke after the bottom dead center of the intake stroke. ) Can be set to an appropriate angle.

  Similarly to the third embodiment, the intake valve 12 is opened at, for example, a crank angle of 30 degrees before the bottom dead center (BDC) of the rear rest stroke, and this opened state is the end of the rear rest stroke. Until maintained. The time when the intake valve 12 is temporarily opened (valve opening timing) is an angle range between 20 degrees and 90 degrees before the bottom dead center of the post-pause stroke (from 810 degrees to 880 in the timing chart of FIG. 5). The angle range can be set to an appropriate angle, and, as described above, 1.5 times this angle from an angle equal to the crank angle of the valve closing timing closed late near the bottom dead center of the intake stroke. It is desirable to set an appropriate crank angle in the angle range of the angle.

  In such an engine, the closing timing of the intake valve 12 is made later than the bottom dead center of the intake stroke so that the intake amount of the air-fuel mixture flowing into the cylinder 2 is reduced, so that the second embodiment The same effect is achieved. In addition, by reducing the intake amount of the air-fuel mixture in this way, the air-fuel mixture can be re-inhaled through the intake passage 10 when the intake valve 12 is opened in the post-pause stroke. When the intake valve 12 is opened in the post-pause stroke, the air-fuel mixture is re-inhaled through the intake air passage 10 as the piston 6 moves toward the bottom dead center. The flow of the air-fuel mixture existing in the air-fuel mixture is promoted, and the same effect as the third embodiment is achieved with respect to the flow of the air-fuel mixture.

  Next, a fifth embodiment of the engine according to the present invention will be described with reference to FIG. 6A is an operation diagram of the engine of the fifth embodiment, FIG. 6B is an opening / closing timing chart showing opening / closing timings of the intake valve and the exhaust valve, and FIG. 6C is a crank angle and a piston position. It is explanatory drawing which shows the relationship.

  In FIG. 6, in this embodiment, the configuration of the engine itself is substantially the same as that of the first embodiment described above, but the intake valve 12 is moved earlier than the bottom dead center near the bottom dead center (BDC) of the intake stroke. The exhaust valve 16 is configured to be closed and opened near the bottom dead center of the post-pause stroke in the pause stroke.

  The intake valve 12 descends from the top dead center (TDC) of the piston 6 to the bottom dead center (BDC) during the intake stroke and closes at a crank angle of 30 degrees, for example, on the near side of the bottom dead center of the intake stroke. The valve closing timing of the intake valve 12 can be set in the same manner as in the first embodiment. Further, in this embodiment, instead of the intake valve 12 of the third embodiment, the exhaust valve 16 is opened at, for example, a crank angle of 30 degrees on the near side of the bottom dead center (BDC) of the post-pause stroke in the pause stroke, This open state is maintained until the end of the post-pause stroke, and the timing for temporarily opening the exhaust valve 16 can be set similarly to the timing for opening and closing the intake valve 12 of the third embodiment.

  In the fifth embodiment, by making the closing timing of the intake valve 12 earlier than the bottom dead center of the intake stroke, the intake amount of the air-fuel mixture flowing into the cylinder 2 is reduced, and the first embodiment is the same as the first embodiment. The effect is achieved in the same way. Further, by reducing the intake amount of the air-fuel mixture in this way, it becomes possible to allow the exhaust gas to flow through the exhaust passage 14 when the exhaust valve 16 is opened in the post-pause stroke. Then, when the exhaust valve 16 is opened in the post-pause stroke, the exhaust gas in the exhaust passage 14 flows into the combustion chamber 8 as the piston 6 moves toward the bottom dead center, and the exhaust chamber flows into the combustion chamber. The flow of the air-fuel mixture existing in 8 is promoted, and the combustion efficiency of the air-fuel mixture can be increased by the flow of the air-fuel mixture.

  The time when the exhaust valve 16 is temporarily opened (opening / closing timing) is an angle range between 20 degrees and 90 degrees before the bottom dead center of the post-pause stroke (from 810 degrees to 880 in the timing chart of FIG. 6). Of the angle range), and an angle range of 1.5 times this angle from an angle equal to the crank angle of the valve closing timing that closes early near the bottom dead center of the intake stroke. An appropriate crank angle is desirable, and by setting the opening / closing timing to such an angle, the shortage of the air-fuel mixture that has decreased in the intake stroke is released to the combustion chamber 8 by releasing the exhaust valve 16. Inflow.

  Next, a sixth embodiment of the engine according to the present invention will be described with reference to FIG. 7A is an operation diagram of the engine of the sixth embodiment, FIG. 7B is an opening / closing timing chart showing opening / closing timings of the intake valve and the exhaust valve, and FIG. 7C is a crank angle and a piston position. It is explanatory drawing which shows the relationship.

  In FIG. 7, in this embodiment, the configuration of the engine itself is substantially the same as that of the first embodiment described above, but the intake valve 12 is made slower than the bottom dead center near the bottom dead center (BDC) of the intake stroke. The exhaust valve 16 is configured to be closed and opened near the bottom dead center of the post-pause stroke in the pause stroke.

  As in the second embodiment, the intake valve 12 descends from the top dead center (TDC) of the piston 6 to the bottom dead center (BDC) during the intake stroke, and is suspended before the bottom dead center of the intake stroke. For example, when the intake valve 12 is closed at the crank angle of 30 degrees in the stroke (valve closing timing) can be set in the same manner as in the second embodiment. Further, the exhaust valve 16 is opened, for example, at a crank angle of 30 degrees before the bottom dead center (BDC) of the post-pause stroke in the pause stroke, and this open state is maintained until the end of the post-pause stroke. Can be set in the same manner as the opening / closing timing of the exhaust valve 16 of the fifth embodiment.

  In the sixth embodiment, by closing the closing timing of the intake valve 12 from the bottom dead center of the intake stroke, the intake amount of the air-fuel mixture flowing into the cylinder 2 is reduced, and the second embodiment and The effect is achieved in the same way. Further, by opening the exhaust valve 16 in the post-pause stroke, the exhaust gas in the exhaust passage 14 flows into the combustion chamber 8 with the movement toward the bottom dead center of the piston 6 and is combusted by the inflowing exhaust gas. The flow of the air-fuel mixture existing in the chamber 8 is promoted, and the same effect as in the fifth embodiment is achieved.

  In the third and fourth embodiments described above, the intake valve 12 is temporarily opened to increase the flow of the air-fuel mixture. In the fifth and sixth embodiments described above, the exhaust valve is used instead of the intake valve 12. 16 is temporarily opened, but instead of this configuration, both the intake valve 12 and the exhaust valve 16 may be temporarily opened.

  In the third to sixth embodiments described above, one pause stroke is provided between the intake stroke and the compression / ignition stroke, but two or more pause strokes may be provided. In this case, when the closing timing of the intake valve 12 is advanced, the intake stroke comes before the bottom dead center of the intake stroke, but when the closing timing is delayed, it becomes the pre-pause stroke in the first pause stroke after the intake stroke, The opening / closing timing for temporarily releasing the intake valve 12 and / or the exhaust valve 16 is a post-pause stroke in the final pause stroke.

  While various embodiments of the engine according to the present invention have been described above, the present invention is not limited to such embodiments, and various modifications and corrections can be made without departing from the scope of the present invention.

  For example, in the above-described embodiment, description has been made by applying to an engine in which an air-fuel mixture is burned by spark ignition using an ignition plug. However, an air-fuel mixture is compressed and ignited and burned without using an ignition plug. The compression / ignition stroke in the engine using the spark plug corresponds to the compression stroke in the engine not using the spark plug, and the term “compression / ignition stroke” in this specification is It is used in a concept including “compression stroke” in an engine that does not use a spark plug.

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder 4 Engine main body 6 Piston 8 Combustion chamber 10 Intake flow path 12 Intake valve 14 Exhaust flow path 16 Exhaust valve 22 Valve mechanism

Claims (2)

A reciprocating operation is performed between a top dead center and a bottom dead center, and an intake valve disposed on the suction side for sucking air-fuel mixture into the cylinder, an exhaust valve disposed on the exhaust side for discharging combustion gas in the cylinder, and the top dead center. A piston that moves, and by opening and closing the intake valve and the exhaust valve accompanying the reciprocating movement of the piston , an intake stroke, a compression / ignition stroke, an expansion stroke, and an exhaust stroke are performed in this order in one cycle. an engine that performs increased stroke cycle operation performed by adding one or more between the four strokes and is separate from the rest stroke reciprocating the piston is without combustion the intake stroke the compression and ignition strokes of ,
In the intake stroke, the intake valve that is open is closed in an angle range of a crank angle of 20 to 90 degrees on the near side of the bottom dead center of the intake stroke, and in the rest stroke, the intake valve and the exhaust valve are closed. The piston is reciprocated with the valve closed, and in the final resting stroke before the compression / ignition stroke, the piston moves from the top dead center to the bottom dead center, and then at the bottom dead center before the rest stroke. An engine characterized by opening the intake valve and / or the exhaust valve . The intake valve and / or the exhaust valve are opened in an angle range of a crank angle of 20 to 90 degrees on the near side of the bottom dead center of the rear rest stroke in the last rest stroke before the compression / ignition stroke. The engine according to claim 1 .

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