JP2013174215A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a configuration, and to increase the recovery efficiency of energy in an internal combustion engine including an auxiliary cylinder for recovering the energy of combustion gas other than a combustion cylinder.SOLUTION: A combustion cylinder 4 is formed to have a posture orthogonal to an axis of a crankshaft 9; and a main piston 7 and the crankshaft 9 are connected by a first connecting rod 12. An auxiliary cylinder 6 has a larger diameter than the combustion cylinder 4 and is formed at an offset position from the combustion cylinder 4. An auxiliary piston 8 and the crankshaft 9 are connected by a second connecting rod 18. The main piston 7 and the auxiliary piston 8 are connected to the single crankshaft 9, thus simplifying a configuration, and the auxiliary piston 8 can function as a balancer to the main piston 7. As the second connecting rod 18 is inclined with respect to the axis of the auxiliary cylinder 6, the energy of the descending motion of the auxiliary piston 8 can be efficiently converted into the rotational energy of the crankshaft 9.

Description

The present invention relates to a four-cycle internal combustion engine having an auxiliary cylinder for energy recovery in addition to a combustion cylinder.

  In a reciprocating internal combustion engine, the piston moves in the direction of the crankshaft by the combustion gas, but the combustion gas maintains a positive pressure even when the piston has moved all the way to the bottom dead center, so energy is wasted. It has been. Therefore, an auxiliary cylinder for energy recovery is provided in addition to the combustion cylinder, and the combustion gas is moved to the auxiliary cylinder when the combustion cylinder is in the exhaust stroke, and the auxiliary piston fitted in the auxiliary cylinder is driven by the combustion gas. It has been proposed to do.

  As an example, Patent Document 1 discloses a configuration in which a combustion cylinder and an auxiliary cylinder are arranged in series, and the main piston of the combustion cylinder and the auxiliary piston of the auxiliary cylinder are connected to the crankshaft via connecting rods, respectively. Is disclosed. On the other hand, Patent Document 2 discloses a mechanism in which the auxiliary piston of the auxiliary cylinder is connected to a dedicated auxiliary crankshaft, and the rotation of the auxiliary crankshaft is transmitted to the crankshaft (main crankshaft) of the combustion cylinder through a chain. Has been.

  In any of the patent documents, the inner diameter (volume) of the auxiliary cylinder is larger than the inner diameter (volume) of the combustion cylinder, and the combustion gas flows into the auxiliary cylinder by depressurizing the combustion gas. (Ie, the combustion gas does the work).

Japanese Utility Model Publication No. 17-809 Japanese Utility Model No. 4-17117 microfilm

  In Patent Document 1, since the combustion cylinder and the auxiliary cylinder share the crankshaft, there is an advantage that the power take-out mechanism is simplified. However, when the main piston of the combustion cylinder is at the bottom dead center, the auxiliary cylinder assists. Since the piston is at top dead center, there is a problem that it is difficult to efficiently transmit the descending energy of the auxiliary piston to the crankshaft.

  In other words, in a state where the auxiliary piston descends from the top dead center during the expansion stroke, the connecting rod is inclined in the rotational direction with respect to the axis of the auxiliary cylinder so that a large moment can be transmitted to the crankshaft. Although the transmission efficiency is good, in Patent Document 1, since the auxiliary piston is pushed down with the connecting rod almost parallel to the axis of the auxiliary cylinder, the efficiency of transmitting the force acting on the auxiliary piston as a moment to the crankshaft is poor. .

  On the other hand, in Patent Document 2, when the main piston of the combustion cylinder is at the bottom dead center, the auxiliary piston of the auxiliary cylinder is slightly lowered from the top dead center. Has the advantage of being able to communicate efficiently. However, in Patent Document 2, when the exhaust gas flows in from the combustion cylinder, there is a considerably large space between the auxiliary piston and the cylinder head. Therefore, the expansion rate of the combustion gas sent from the combustion cylinder As a result, the energy recovery efficiency may not be good. That is, the patent document has a problem that a large kinetic energy cannot be applied to the auxiliary piston.

  Further, in Patent Document 2, since the rotation of the auxiliary crankshaft is transmitted to the main crankshaft by a chain, not only the structure becomes complicated and the engine becomes large, but also the energy recovery efficiency by the resistance between the chain and the sprocket. There is a problem that will decrease. Further, in Patent Document 1, since the auxiliary piston moves in the opposite direction to the main piston, the inertial force of the main piston can be canceled to contribute to suppression of engine vibration. However, as in Patent Document 2, the main piston and the auxiliary piston Are connected to different crankshafts, there is a problem that the auxiliary piston cannot be effectively used for vibration suppression of the main piston.

  The present invention has been made in view of such a current situation, and intends to provide a further improved internal combustion engine, such as being excellent in energy recovery efficiency while simplifying the structure as much as possible.

  The present invention of claim 1 is a four-cycle combustion cylinder in which a main piston reciprocating by combustion of fuel is slidably fitted, a crankshaft in which the main piston is connected via a connecting rod, The present invention is intended for an internal combustion engine having an energy recovery auxiliary cylinder in which an auxiliary piston driven by exhaust gas discharged from the combustion cylinder is slidably fitted.

  According to a first aspect of the present invention, in the above configuration, the combustion cylinder is disposed in a posture substantially orthogonal to an axis of the crankshaft, while the auxiliary cylinder is viewed from the axial direction of the crankshaft. The auxiliary piston is connected to the crankshaft via a connecting rod and is shifted to the right or left of the combustion cylinder, and the phase between the reciprocating motion of the main piston and the reciprocating motion of the auxiliary piston Is varied by approximately 180 degrees depending on the rotation angle of the crankshaft.

  The invention of claim 2 is a four-cycle combustion cylinder in which a main piston that reciprocates by combustion of fuel is slidably fitted, a crankshaft in which the main piston is connected via a connecting rod, And an auxiliary cylinder fitted with an auxiliary piston connected to a crankshaft via a connecting rod, and the combustion cylinder and the auxiliary cylinder communicate with a sealed crank chamber, and the main piston It is intended for an internal combustion engine having a configuration in which the internal pressure of the crank chamber varies due to reciprocation.

  In the above configuration, the crank chamber is provided with a blow-by gas recirculation control valve that discharges internal gas, and the blow-by gas recirculation control valve is closed when the auxiliary cylinder is in the up stroke, and is opened when the auxiliary cylinder is in the down stroke. To be controlled.

  According to the present invention of claim 1, since the main piston and the auxiliary piston are connected to a common crankshaft, the power take-off mechanism can be simplified and the enlargement of the engine can be suppressed, and the auxiliary piston can be used as a balancer with respect to the main piston. Therefore, it can contribute to suppression of engine vibration and high speed rotation.

  In addition, the combustion cylinder and the auxiliary cylinder are not arranged in series, but are shifted to the left or right (offset) when viewed from the axial direction of the crankshaft, so that the auxiliary piston is at the top dead center. In addition, the connecting rod connected to the auxiliary piston is inclined with respect to the axis of the auxiliary cylinder. Therefore, the descending movement of the auxiliary piston when the auxiliary cylinder is in the expansion stroke is efficiently converted into the rotation of the crankshaft. can do. Further, since the expansion stroke of the auxiliary cylinder can be started from the state where the auxiliary piston is at the top dead center, the expansion rate of the combustion gas sent from the combustion cylinder can be increased.

  As described above, the energy recovery efficiency can be improved by combining the ability to efficiently convert the kinetic energy of the auxiliary piston into the rotational energy of the crankshaft and the improvement of the expansion rate of the combustion gas sent from the combustion cylinder. it can. In particular, when the combustion cylinder is an in-line two-cylinder engine having a 360 ° CA phase arrangement, the strokes of the two cylinders are shifted by 360 degrees, and therefore, the reciprocating motion of the auxiliary piston can be effectively used.

  Now, in the combustion cylinder, a phenomenon is seen in which combustion gas blows through the piston into the crank chamber. Therefore, a blow-by gas recirculation passage for recirculating the blow-by gas blown into the crank chamber to the intake system is provided, and the recirculation control is performed by the blow-by gas recirculation control valve. Since the crank chamber is maintained in a positive pressure state during the expansion stroke, the auxiliary piston can be pushed up in the direction of the top dead center by the combustion gas (blow-by gas) flowing into the crank chamber.

  As a result, energy that has been discarded in the past can be recovered and contribute to improvement in fuel consumption. Further, since the auxiliary piston can function as a balancer for the main piston, vibration can be suppressed and high-speed rotation can be supported. In the case of claim 2 as well, when the combustion cylinder is an in-line two-cylinder engine having a 360 ° CA phase arrangement, the ascending stroke of the auxiliary piston can always be used for energy recovery, and the efficiency is high. Needless to say, the invention of claim 1 can be combined with the invention of claim 2.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment, (A) is a top view of the cylinder block in the state which also displayed some cylinder heads, (B) is BB sectional drawing of (A). It is the II-II sectional view taken on the line of FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is a schematic diagram for demonstrating the motion of 1st Embodiment. It is a typical sectional side view which shows 2nd Embodiment. It is a figure which shows 3rd Embodiment.

(1) Structure of First Embodiment Next, an embodiment of the present invention will be described with reference to the drawings. First, a first embodiment shown in FIGS. 1 to 4 will be described. The internal combustion engine includes an engine body 1 having a cylinder block 2 and a cylinder head 3 as main elements. The cylinder block 2 includes two combustion cylinders (main cylinders) 4 arranged in series, and a combustion cylinder. The auxiliary cylinder 6 is formed on one side of the line 5 connecting the centers of the four. The combustion cylinder 4 and the auxiliary cylinder 6 are arranged in parallel. The cylinder block 2 is formed with a water jacket surrounding at least the combustion cylinder 4, but is omitted in the drawing.

  A main piston 7 is slidably fitted in the combustion cylinder 4, and an auxiliary piston 8 is slidably fitted in the auxiliary cylinder 6. Further, a crankshaft 9 is rotatably held on the cylinder block 2. The auxiliary piston 8 is lighter and simpler than the main piston 7.

  The crankshaft 9 is disposed so as to substantially overlap the line 5 of the combustion cylinders 4 when viewed from the axial direction of the combustion cylinders 4. Therefore, as shown in FIG. 2, when viewed from the axial direction of the crankshaft 9, the axis of the combustion cylinder 4 is substantially orthogonal to the axial line of the crankshaft 9 (actually, reverse rotation of the crankshaft 9 is prevented). 2 for increasing the inclination of the connecting rod and obtaining a large rotational moment in the vicinity of the maximum combustion pressure value, the center of the crankshaft 9 is moved relative to the center of the combustion cylinder 4 in the state of FIG. Often slightly to the right.)

  The crankshaft 9 has two first crankpins 10 corresponding to the combustion cylinders 4. The first crankpin 10 and the main piston 7 are relative to each other by the first piston pin 11 and the first connecting rod 12. It is connected freely. The first crank pin 10 is provided integrally with the first crank arm 13.

  The crankshaft 9 is provided with a pair of second crank arms 15 corresponding to the auxiliary cylinders 6, and a second crank pin 16 and an auxiliary piston 8 provided on the second crank arm 15 are connected to the second piston pin 17 and the second piston 8. The connecting rods 18 are connected so as to be relatively movable. In the present embodiment, the second piston pin 17 is provided on the foot 19 projecting downward from the auxiliary piston 8, but the second piston pin 17 can also be disposed in the cavity of the auxiliary piston 8.

  As shown in FIG. 1A, both ends of the crankshaft 9 are main journals 9a and are rotatably held by the cylinder block 2 via bearings (not shown). Further, a portion of the crankshaft 9 between the adjacent crank arms 13 and 15 is an intermediate journal 9b, and is rotatably held by the cylinder block 2 via a bearing (not shown).

  In this embodiment, the reciprocating stroke of the auxiliary piston 8 (rotating diameter of the second crankpin 16) is set larger than the reciprocating stroke of the main piston 7 (rotating diameter of the first crankpin 10). Therefore, the reciprocating speed of the auxiliary piston 8 is larger than the reciprocating speed of the main piston 7. Further, the first crankpin 10 and the second crankpin 16 are located on the opposite sides of the rotation axis of the crankshaft 9. That is, the first crankpin 10 and the second crankpin 16 are out of phase with each other by 180 ° in the rotation direction of the crankshaft 9.

  Two intake ports 20 and two exhaust ports 21 are formed in the cylinder head 3 for each combustion cylinder 4. The exhaust port 21 is formed at a portion close to the auxiliary cylinder 6 across the line 5 of the combustion cylinders 4. The intake port 20 is opened and closed by an intake valve 22, and the exhaust port 21 is opened and closed by an exhaust valve 23. The intake valve 22 is opened and closed by an intake camshaft 24, and the exhaust valve 23 is opened and closed by an exhaust camshaft 25.

  As shown in FIG. 1 (A), two suction ports 26 and two discharge ports 27 are formed in a portion corresponding to the auxiliary cylinder 6 in the cylinder head 3. The two suction ports 26 are formed side by side in the direction of the crankshaft 9, and the two discharge ports 27 are also formed side by side in the direction of the crankshaft 9. The two suction ports 26 are gathered in one collecting port 28, and the four exhaust ports 21 of the two combustion cylinders 4 communicate with the collecting port 28. Accordingly, the exhaust port 21 discharged from the combustion cylinder 4 flows into the auxiliary cylinder 6 from the suction port 26 via the collecting port 28.

  As shown in FIG. 3, the suction port 26 of the auxiliary cylinder 6 is opened and closed by a suction valve 29, and the discharge port 27 is opened and closed by a discharge valve 30. The suction valve 29 is driven by the suction camshaft 31 and the discharge valve 30 is driven by the discharge camshaft 32. As shown by the one-dot chain line in FIG. 2, both the suction valve 29 and the discharge valve 30 are exhaust cams. It can also be driven by rocker arms 33 and 34 that rotate on the shaft 25.

(2) Action As shown in FIG. 4, when one main piston 7 of the two combustion cylinders 4 changes from the expansion stroke to the exhaust stroke, the suction of the exhaust valve 23 and the auxiliary cylinder 6 of the combustion cylinder 4 is performed. Valve 29 opens. Then, the auxiliary cylinder 6 has a positive pressure on the auxiliary cylinder 6 because the volume (inner diameter) of the auxiliary cylinder 6 is larger than the volume (inner diameter) of the combustion cylinder 4 and the reverse speed of the auxiliary piston 8 is larger than the ascent speed of the main piston 7. Exhaust gas flows into the auxiliary cylinder 6 from the combustion cylinder 4 while expanding. Thereby, the pressure of the combustion gas after the work of pushing down the main piston 7 can be effectively utilized and taken out as the rotational power of the crankshaft 9.

  In this case, since the auxiliary cylinder 6 is disposed at a position offset with respect to the combustion cylinder 4, the second connecting rod 18 is located with respect to the axis of the auxiliary cylinder 6 while the auxiliary piston 8 is at the top dead center. (The second connecting rod 18 is in a state perpendicular to the line orthogonal to the line connecting the axis of the crankshaft 9 and the second crankpin 16 in a state where the auxiliary piston 8 is at the top dead center. And is inclined by an angle of θ).

  For this reason, the second crankpin 16 is pushed from the lateral direction by the downward movement of the auxiliary piston 8, and as a result, the force of the auxiliary piston 8 can be efficiently transmitted to the crankshaft 9 as a moment. When the auxiliary cylinder 6 is shifted to the left when viewed from the axial direction of the crankshaft 9 as in this embodiment, the lower end of the second connecting rod 18 is shifted to the right, so that the crankshaft 19 is rotated clockwise. Rotate. When it is shifted to the right as viewed from the axial direction (when FIGS. 2, 3 and 4 are viewed from the side opposite to the paper surface), it rotates counterclockwise.

  In addition, since the main piston 7 and the auxiliary piston 6 share one crankshaft 9, the structure can be simplified, and the auxiliary piston 8 can function as a balancer for the main piston 7. Vibration can be suppressed and high-speed rotation can be supported.

  It is preferable to make the reciprocating stroke of the auxiliary piston 8 larger than the reciprocating stroke of the main piston 7 as in the present embodiment, because the expansion of the exhaust gas in the auxiliary cylinder 6 can be promoted. If the descending speed of the auxiliary piston 8 is higher than the ascending speed of the main piston 7, even if the combustion cylinder 4 and the auxiliary cylinder 6 have the same inner diameter, the exhaust gas flowing from the combustion cylinder 4 is used as the auxiliary cylinder. 6 can be inflated. Therefore, the inner diameter of the auxiliary cylinder 6 is not necessarily larger than the inner diameter of the combustion cylinder 4.

(2). Other Embodiments FIG. 5 shows a second embodiment. This embodiment is basically the same as the first embodiment. However, as a unique configuration, a blow-by gas recirculation control valve 36 is provided at an appropriate part of the cylinder block 2 and the combustion blown through from the combustion chamber to the crank chamber 37 is performed. The gas can be recirculated to the intake system. Although the oil pan 38 is fixed to the cylinder block 2, the inside of the cylinder block 2 and the oil pan 38 is sealed, and the gas accumulated inside can escape only from the blow-by gas recirculation control valve 36.

  Further, the volume of one auxiliary cylinder 6 is larger than the total volume of the two combustion cylinders 4, and the ascending speed of the auxiliary piston 8 is larger than the descending speed of the main piston 7.

  The combustion cylinders 4 are two cylinders. Therefore, the main pistons 7 of the two combustion cylinders 4 are reciprocating at the same time with the stroke phases being different by 360 degrees. On the other hand, the auxiliary piston 8 is 180 degrees out of phase with respect to the two main pistons 7. Therefore, the auxiliary piston 8 functions as a balancer with respect to the main piston 7.

  In this embodiment, every time the crankshaft 9 rotates 360, explosion strokes occur alternately in the two combustion cylinders 4, but when the main piston 7 is in the downward stroke, the blow-by gas recirculation control valve 36 is closed. Thus, the pressure of the combustion gas blown into the crank chamber 37 is effectively used for raising the auxiliary piston, and thereby auxiliary power is applied to the crankshaft 9. For this reason, fuel consumption can be improved. When the auxiliary piston 8 is in the downward stroke (expansion stroke), the blow-by gas recirculation control valve 36 is opened. The blow-by gas recirculation control valve is electrically opened and closed by a motor, electromagnetic solenoid or the like.

  The auxiliary cylinder 6 can be used only for the pressure recovery and balancer function of the blow-by gas, but in combination with the first embodiment, the residual pressure of the combustion gas discharged from the combustion cylinder 4 is reduced in the downward stroke. It is preferable to recover and to recover the pressure of blow-by gas in the ascending stroke.

  In the above two embodiments, the combustion cylinder 4 and the auxiliary cylinder 6 are formed in parallel. However, as shown in FIG. 6 as the third embodiment, the axis of the auxiliary cylinder 6 is the center of the combustion cylinder 4. It is also possible to incline with respect to the axis. Thereby, the crankshaft 9 can be rotated without difficulty by the auxiliary piston 8.

  The present invention can be embodied in a vehicle internal combustion engine. Therefore, it can be used industrially.

2 Cylinder Block 3 Cylinder Head 4 Combustion Cylinder 5 Combustion Cylinder Line 6 Auxiliary Cylinder 7 Main Piston 8 Auxiliary Piston 9 Crankshaft 12 First Connecting Rod 18 Second Connecting Rod 20 Intake Port 21 Intake Port 22 Intake Valve 23 Exhaust Valve 36 Blow-by gas recirculation control valve 37 Crank chamber

Claims (2)

A four-stroke combustion cylinder in which a main piston that reciprocates by combustion of fuel is slidably fitted, a crankshaft to which the main piston is connected via a connecting rod, and exhausted from the combustion cylinder An energy recovery auxiliary cylinder in which an auxiliary piston driven by exhaust gas is slidably fitted,
The combustion cylinder is arranged in a posture substantially orthogonal to the axis of the crankshaft, while the auxiliary cylinder is arranged to be shifted to the right or left of the combustion cylinder when viewed from the axial direction of the crankshaft. The auxiliary piston is connected to the crankshaft via a connecting rod, and the phase of the reciprocating motion of the main piston and the reciprocating motion of the auxiliary piston is made to differ by approximately 180 degrees depending on the rotation angle of the crankshaft. Yes,
Internal combustion engine. A four-stroke combustion cylinder in which a main piston that reciprocates by combustion of fuel is slidably fitted, a crankshaft connected to the main piston via a connecting rod, and a connecting rod connected to the crankshaft And the auxiliary cylinder connected with the auxiliary piston, the combustion cylinder and the auxiliary cylinder communicate with a closed crank chamber, and the internal pressure of the crank chamber is reciprocated by the main piston. Is a configuration that fluctuates,
The crank chamber is provided with a blow-by gas recirculation control valve that discharges internal gas, and the blow-by gas recirculation control valve is controlled to be closed when the auxiliary cylinder is in the up stroke and open when the auxiliary cylinder is in the down stroke.
Internal combustion engine.

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