JP4581552B2 - Reciprocating internal combustion engine - Google Patents

Description

  The present invention relates to a reciprocating internal combustion engine that converts a reciprocating linear motion of a piston into a rotational motion of a crankshaft and transmits it, and a vehicle equipped with the internal combustion engine.

  As is well known, a reciprocating internal combustion engine mounted on an automobile is a piston-crank that mechanically links a piston in a cylinder and a crankpin of a crankshaft and converts a reciprocating linear motion of the piston into a rotational motion of the crankshaft. It has a mechanism. As this piston-crank mechanism, in a general single link type in which a piston and a crank pin are connected by a single connecting rod, the rotation center of the crankshaft is generally on or near the cylinder center axis, that is, a cylinder. It is located just below.

Patent Document 1 discloses a multi-link type piston-crank mechanism in which a piston and a crank pin are linked by a plurality of links in order to make the piston stroke characteristics and the engine compression ratio variable. Also in this multi-link type configuration, as in the case of the single link type, the center of rotation of the crankshaft is located almost directly below the cylinder on or near the cylinder center axis.
JP 2001-227367 A

  In order to avoid interference between the crankshaft including the counterweight and the piston and the piston when the rotation center of the crankshaft is located almost directly below the cylinder as in the above-described conventional reciprocating internal combustion engine, the piston and the cylinder Needs to be arranged at a position deviating above the engine from the rotation locus of the crankshaft. For this reason, the size of the internal combustion engine in the vertical direction, that is, the overall height of the engine is increased, leading to an increase in the size of the internal combustion engine and a decrease in vehicle mountability. In particular, in an in-line multi-cylinder type internal combustion engine, the overall height of the engine tends to be high, and the position of the engine hood of the vehicle increases according to the overall height of the engine. It becomes difficult to ensure a sufficient clearance between the inner surface of the hood and the upper part of the internal combustion engine.

The present invention has been made paying attention to such a problem. The piston in the cylinder and the crank pin of the crankshaft are mechanically linked, and the reciprocating linear motion of the piston is changed to the rotational motion of the crankshaft. In a vehicle having a piston-crank mechanism for conversion and having a reciprocating internal combustion engine for taking out output as rotational motion of the crankshaft, the center of rotation of the crankshaft is disposed on the side of the cylinder, and the piston- The crank mechanism has a rocker arm swingable around a fulcrum, and an upper end connected to the piston by a piston pin so as to be relatively rotatable, and a lower end connected to an end of the rocker arm by a first connecting pin so as to be relatively rotatable. The first link and the upper end are connected to the crank pin so as to be relatively rotatable. And a second link which lower end is linked to the other end relative rotation of the rocker arm by a second connecting pin, and the reciprocating internal combustion engine, in an engine room of a vehicle front, the axial direction of the crankshaft A drive shaft that is mounted in a lateral orientation along the vehicle width direction and that has drive wheels connected to both ends passes between the first link and the second link and penetrates the reciprocating internal combustion engine. It is characterized by that.

  The “side” of the “side of the cylinder” means a side in the direction along the engine width direction. Therefore, in the present invention, the cylinder and the crankshaft (rotation center thereof) are arranged side by side along the engine width direction. The “engine width direction” is a direction perpendicular to the engine longitudinal direction along the axis of the crankshaft and perpendicular to the engine vertical direction, and generally corresponds to the thrust-anti-thrust direction of the piston. The above-mentioned “up-down direction of the engine” is a direction along the cylinder central axis in an in-line internal combustion engine in which a plurality of cylinders are arranged in a row, and a bank angle is defined in a V-type internal combustion engine in which two cylinder rows form a V shape. It is a direction along the bank center line that bisects.

  According to the present invention, the overall height of the reciprocating internal combustion engine can be suppressed low by disposing the rotation center of the crankshaft on the side of the cylinder. Therefore, in particular, in an in-line multi-cylinder reciprocating internal combustion engine in which the total engine height tends to be long, the internal combustion engine can be configured to be compact as a whole, and vehicle mountability can be improved.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the direction (vertical direction in FIG. 1) along the center axis of the cylinder 6 (reciprocating axis of the piston 3) is called the engine vertical direction Fh, and the rotation axis direction of the crankshaft 4, that is, the cylinder row direction ( 1 is called the engine longitudinal direction Fl, and the thrust-anti-thrust direction (left-right direction in FIG. 1) of the piston 3 perpendicular to both the engine vertical direction Fh and the engine longitudinal direction Fl is the engine width. Called the direction Fb.

  FIG. 1 is a cross-sectional view schematically showing a reciprocating internal combustion engine according to a first embodiment of the present invention. The reciprocating internal combustion engine E is an in-line multi-cylinder internal combustion engine in which a plurality of (for example, 4 or 6) cylinders 6 are arranged in a line along the cylinder row direction, and is similar to the second embodiment described later. An engine room ER disposed in front of the vehicle is mounted in a lateral orientation in which the engine vertical direction Fh is along the vehicle vertical direction and the engine width direction Fb is along the vehicle front-rear direction (see FIGS. 5 and 6).

  A plurality of cylinders 6 are formed in the cylinder block 21 along the cylinder row direction Fl, and the pistons 3 are slidably fitted in the cylinders 6. A cylinder head 8 is fixed to the upper surface of the cylinder block 21 so as to cover the upper surface of the cylinder 6, and a pent roof type defining a combustion chamber 22 between the lower surface of the cylinder head 8 and the upper surface of the piston 3. The combustion chamber 22 is formed. A head cover 23 that rotatably supports the intake camshaft 9I and the exhaust camshaft 9E together with the cylinder head 8 is fixed to the upper surface of the cylinder head 8. The cylinder head 8 is formed with an intake port 24I and an exhaust port 24E that are connected to the combustion chamber 22. An internal passage communicating with the exhaust port 24E is formed in the exhaust manifold 25E attached to the side surface of the cylinder head 8. An oil pan 26 that receives and stores the lubricating oil is attached to the lower surface of the cylinder block 21.

  The reciprocating internal combustion engine E is a piston that mechanically links the piston 3 and the crankpin 5 of the crankshaft 4 to convert the reciprocating linear motion of the piston 3 in the cylinder 6 into the rotational motion of the crankshaft 4. A crank mechanism 30 is provided; The piston-crank mechanism 30 has a multi-link configuration in which the piston 3 and the crank pin 5 are linked by a plurality of links. That is, the multi-link type piston-crank mechanism 30 includes a rocker arm 31 that can swing around the fulcrum 1, a first link 32 that connects one end of the rocker arm 31 and the piston 3, the other end of the rocker arm 31, and a crankshaft. And a second link 33 connecting the four crankpins 5 to each other. The piston 3 and the upper end of the first link 32 are connected by a piston pin 34 so as to be relatively rotatable. The lower end of the first link 32 and one end of the rocker arm 31 are connected to each other by a first connecting pin 35 so as to be relatively rotatable. The other end of the rocker arm 31 and the lower end of the second link 33 are connected by a second connecting pin 36 so as to be relatively rotatable.

  This multi-link type piston-crank mechanism 30 continuously changes the stroke characteristics and engine compression ratio of the piston 3 by displacing the rocking fulcrum 1 of the rocker arm 31 with respect to the engine stationary body such as the cylinder block 21. In other words, it is configured as a variable compression ratio mechanism that makes the engine compression ratio variable. The variable compression ratio means includes a control shaft 41 extending in the cylinder row direction Fl parallel to the crankshaft 4 and a plurality of control eccentric shaft portions 42 provided eccentrically to the control shaft 41 corresponding to each cylinder 6. Have. A central portion of the rocker arm 31 is swingably attached to the circular outer peripheral surface of each control eccentric shaft portion 42. Therefore, the rocker arm 31 can swing around the axis of the control eccentric shaft portion 42 as the fulcrum 1. By changing the rotational position of the control shaft 41, the position of the rocking fulcrum 1 of the rocker arm 31 is displaced, and the engine compression ratio is changed. The rotational position of the control shaft 41 is changed and held by a variable compression ratio actuator 43 such as an electric type or a hydraulic type. The operation of the variable compression ratio actuator 43 is controlled by a control signal output from the engine control unit 44 according to engine operating conditions such as engine load and engine speed.

  FIG. 2 schematically shows the link row of the multi-link type piston-crank mechanism 30 described above, in particular, the posture of the link center line and the link connection point every 90 ° CA. The point position, (4), corresponds to the piston bottom dead center position. In the piston lowering process shown in (2)-(3)-(4) of FIG. 2, as the piston 3 is lowered, the first link 32 linked to the piston 3 is lowered, and one end of the rocker arm 31 is moved. The second link 33 linked to the other end of the rocker arm 31 is raised, and the crank pin 5 linked to the second link 33 is raised while revolving clockwise around the rotation center of the crankshaft 4. . On the contrary, in the piston ascending stroke shown in (4)-(1)-(2) of FIG. 2, the crankpin 5 descends while revolving clockwise, and the second link 33 descends, via the rocker arm 31. Thus, the first link 32 rises and the piston 3 rises. Thus, in this multi-link type piston-crank mechanism 30, the vertical component of the vertical movement of the piston 3 and the revolution movement of the crank pin 5 is opposite to the general single-link type piston-crank mechanism. Are in a relationship corresponding to the opposite direction.

  FIG. 3 (A) shows a comparative example using a single link type piston-crank mechanism in which the piston 3 and the crank pin 5 are linked by a single connecting rod 12, and FIG. The present embodiment using the link type piston-crank mechanism 30 is shown. With reference to this FIG. 3 etc., the characteristic structure and effect of this embodiment will be described with reference to a comparative example.

  The first link 32, the rocker arm 31, and the second link 33 connected in series are arranged in a substantially U shape, a channel shape, and a U shape each having one side. That is, the first link 32 and the second link 33 face each other substantially in parallel with the cylinder wall 7 interposed therebetween so as to surround the lower part of the cylinder wall 7 located between the cylinder 6 and the crankshaft 4 from three sides. In addition, a rocker arm 31 that connects both the links 31 and 32 is disposed so as to cross the lower side of the cylinder wall 7.

  A rotation center 4 </ b> A of the crankshaft 4 is positioned on the side of a cylinder 6 in which the piston 3 reciprocates linearly and a cylinder cylindrical portion 7 that defines the cylinder 6. That is, the crankshaft 4 and its rotation center 4A are arranged in parallel to the cylinder 6 in the engine width direction Fb. More specifically, the crank center 4A is disposed within the existence range 6D of the cylinder 6 and further within the reciprocation range of the piston 3 in the piston reciprocation direction Fh.

  The control shaft 41 is between the center line 6A of the cylinder 6 and the center line 4A of the crankshaft 4 including the control eccentric shaft portion 42 having the swing fulcrum 1 as the center. It is arranged diagonally below the shaft. The cylinder wall portion 7 located between the cylinder 6 and the crankshaft 4 defines a part of the cylinder 6 whose inner peripheral surface 7A holds the piston 3 so as to be slidable, and its outer periphery. The surface 7B defines a part of the crankcase 27 that houses the crankshaft 4. That is, the cylinder wall portion 7 has both the function of forming the cylinder 6 and the function of forming the crankcase 27.

  The cylinder head 8 is integrally formed with a head extension 8 </ b> A that projects from the portion located above the cylinder 6 toward the engine side. The upper wall surface of the crankcase 27 is defined by the lower surface of the head extension 8A. In other words, the cylinder head 8 is formed with a head extension 8A that protrudes toward the crankshaft side so as to define a part of the crankcase 27.

  As described above, the crankshaft 4 and the rotation center 4A thereof are located on the engine side of the cylinder cylindrical portion 7. Therefore, as shown in FIG. 3, the overall height of the internal combustion engine can be greatly reduced as shown by the arrow Y1, as compared with the comparative example in which the crankshaft 4 is located directly below the cylinder 6. As a result, effects such as downsizing the internal combustion engine and improving vehicle mountability can be obtained.

  In this embodiment, the first link 32 is disposed substantially along the cylinder center axis 6A, and the piston 3 is in the middle of the reciprocating movement range as shown in FIGS. In this state, the link connection point 35 (the axial center position of the first connecting pin 35) 35 between the first link 32 and the rocker arm 31 is disposed at substantially the same height as the rocking fulcrum 1 of the rocker arm 31. ing. Accordingly, as shown in FIG. 1, the movement locus 35A of the link connection point 35 between the first link 32 and the rocker arm 31 has a fan shape that swings up and down substantially along the cylinder center axis Fh. Hardly moves in the direction Fb perpendicular to the reciprocating direction Fh of the piston 3 (that is, the horizontal direction of the internal combustion engine). For this reason, the first link 32 hardly tilts with respect to the center line 6A of the cylinder 6 as the piston 3 reciprocates, and the load that the piston 3 receives from the cylindrical inner surface of the cylinder 6 (that is, piston thrust-antithrust load). ) Is significantly reduced as compared with the comparative example. In the comparative example, when viewed from the piston 3, the center of the crank pin 5 that is the swing fulcrum of the connecting rod 12 swings greatly in the engine width direction Fb along with its own revolution, and the piston thrust when subjected to a combustion load The anti-thrust load becomes very large as compared with the present embodiment.

  As described above, in this embodiment, since the load in the thrust-anti-thrust direction of the piston can be remarkably suppressed as compared with the comparative example, it is required to ensure the expected durability and reliability for the cylinder cylindrical portion 7. Therefore, not only can the piston 3 and the cylinder cylindrical portion 7 be reduced in weight and size, but also the behavior of the piston 3 in the sliding clearance in the cylinder 6 can be greatly reduced. Because of the stability, the striking sound of the piston 3 into the cylinder 6 can be reduced, and the piston length (vertical dimension) considered necessary for stabilizing the behavior of the piston in the sliding clearance can be effectively reduced. Further, since the followability of the well-known piston ring incorporated in the outer periphery of the piston 3 to the cylindrical inner surface of the cylinder 6 is improved, undesirable oil rising from the crankcase 27 and the oil pan 26 to the combustion chamber 22, and the combustion chamber Undesirable oil drop from 22 to the oil pan 26 is less likely to occur, and tension on the inner surface of the cylinder cylindrical portion 7 of the piston ring, that is, mechanical friction generated between the cylinder inner surface and the piston ring can be reduced. There is an advantage that the engine efficiency of the engine can be improved. In particular, in the low / medium speed region that is frequently used in an internal combustion engine for automobiles, the friction generated from the piston ring is very large compared to the friction generated from the cylindrical bearing surface at the connection point. is there.

  In this embodiment, since the crankshaft 4 is not positioned below (directly below) the cylinder 6, the piston 3 and the counterweight 4B between the crankshaft 4 and the crankshaft 4 are in a situation where the piston 3 is at the bottom dead center position as in the comparative example. There is no need to worry about interference. Further, as described above, the first link 32 connected to the piston 3 moves substantially along the cylinder center axis 6A without swinging left and right. Therefore, the bottom dead center position of the piston 3 can be made sufficiently close to the lower end of the cylinder 6, that is, the reciprocating range of the piston 3 can be set by making the maximum use of the vertical dimension of the cylinder 6. It is possible to achieve both suppression of the vertical dimension of the cylinder 6 and expansion of the reciprocating range of the piston 3. Specifically, according to the present embodiment, compared to the comparative example, the cylinder length can be reduced with the same piston stroke amount, and the piston stroke amount can be increased with the same cylinder length. Due to the synergistic effect with the effect of reducing the piston length as described above, a longer piston stroke can be secured with a more compact cylinder.

  In this embodiment, the rotation shaft 4A of the crankshaft 4 is pulled up to the side of the cylinder 6 as compared with the comparative example, and therefore, the suction shaft positioned above the rotation shaft 4A of the crankshaft 4 and the cylinder 6 is used. The distance between the exhaust camshafts 9I and 9E (particularly, the distance in the engine vertical direction) can be reduced. For this reason, the length of a known chain or belt for transmitting the rotation of the crankshaft 4 to the camshafts 9I and 9E can be shortened, the reliability and durability of the chain or belt can be improved, and the crankshaft 4 It becomes easy to suppress flapping of the chain or belt during high-speed operation that rotates at high speed.

  Further, since the distance between the crankcase 27 accommodating the crankshaft 4 and the cylinder head 8 is close, a part 8A of the cylinder head 8 is extended to above the crankshaft 4, and the crankcase 27 is connected to the head extension 8A. By combining the upper surface of the cylinder head 8, the weight and cost can be reduced as compared with the case where the upper wall portion of the crankcase 27 is provided separately from the cylinder head 8. Further, a halved portion 28A of the intake collector portion 28 where the plurality of intake ports 24I merge is formed in the head extension portion 8A that defines the upper surface of the crankcase 27 in this way, and the head extension portion 8A By providing the function as an intake manifold, the number of parts can be reduced compared to the case where the intake manifold 29 is provided separately from the cylinder head 8 as in the comparative example, and the downsizing, weight reduction, and cost reduction can be achieved. An effect can be obtained. In this embodiment, the intake collector portion 28 is defined by a collector cap 28B fixed to the upper surface of the head extension portion 8A and the above-described half portion 28A.

  Since the cylinder wall 7 also has a function of defining a part of the crankcase 27, less material is required compared to the case where the side wall of the crankcase 27 is provided separately from the cylinder wall 7. It is possible to reduce weight, size and cost.

  The control shaft 41 includes a main shaft portion that is rotatably supported by the cylinder block 21 that is an engine stationary body, and a control eccentric shaft portion 42 that is eccentric with respect to the center of the main shaft portion. The rocker arm 31 is swingably supported by the control eccentric shaft portion 42, and the rocker arm 31 can swing with the axis of the control eccentric shaft portion 42 as the swing fulcrum 1. The position of the rocking fulcrum 1 of the rocker arm 31 is changed by controlling the operation of the variable compression ratio actuator 43 according to the operating conditions of the internal combustion engine by the engine control unit 44 and changing the rotational position of the control shaft 41. Displacement with respect to the engine stationary body such as the cylinder block 21 changes the stroke characteristics of the piston 3, that is, the top dead center position and the bottom dead center position of the piston 3. Accordingly, the compression ratio of the internal combustion engine is continuously increased. Can be changed.

  (1) and (2) on the left side of FIG. 4 show the link trains when the rotational position of the control shaft 41 is set to a high compression ratio and the piston 3 is at the top dead center TDC and the bottom dead center BDC, respectively. The arrangement is shown. Also, (3) and (4) on the right side of FIG. 4 are links when the rotational position of the control shaft 41 is set to a low compression ratio and the piston 3 is at the top dead center TDC and the bottom dead center BDC, respectively. The arrangement of the columns is shown. As shown in the figure, when the rocking fulcrum 1 of the rocker arm 31 moves downward, the top dead center position and the bottom dead center position of the piston 3 are moved downward, thereby reducing the compression ratio of the internal combustion engine. You can see that it has been lowered.

  In the present embodiment, the link row composed of the minimum three link elements 31 to 33 for making the compression ratio variable is effectively used, that is, the link elements 31 to 33 arranged in a substantially U-shape are used. By utilizing this, a layout in which the center 4A of the crankshaft 4 is located on the side of the cylinder 6 is easily realized. That is, the link element is not added only for realizing such a layout, but the minimum link rows 31 to 33 necessary for making the compression ratio variable are effectively used, The layout is realized.

  5 and 6 show a reciprocating internal combustion engine according to a second embodiment of the present invention. The basic structure and operational effects of the second embodiment are the same as those of the first embodiment, and the differences from the first embodiment will be mainly described here.

  In the engine room ER in front of the driver's seat of the vehicle, the reciprocating internal combustion engine E according to the present embodiment is mounted in a horizontal position, and auxiliary machines 14 such as an air conditioner compressor, a water pump, a power steering and an alternator, A fan 15, a transmission 16, and the like are mounted. As is well known, the driving force generated by the internal combustion engine E is transmitted to the drive shaft 10 extending in the vehicle width direction via the crankshaft 4 and the transmission 16, and a pair of drive wheels connected to both ends of the drive shaft 10. To T. When the internal combustion engine E is placed horizontally as described above, the vehicle width direction and the engine longitudinal direction Fl coincide with each other, and the drive shaft 10, the crankshaft 4, and the control shaft 41 are arranged along the vehicle width direction. . Reference numeral 17 denotes a side member.

  In this embodiment, the drive shaft 10 is located between the first link 32 and the second link 33 and between the cylinder wall 7 and the crankshaft 4 with respect to the vehicle longitudinal direction (engine width direction) Fb. In addition, it is disposed almost directly above the control shaft 41. That is, a space 10 </ b> A through which the drive shaft 10 passes is secured in the cylinder block 21 between the cylinder wall 7 and the crankshaft 4. Thus, since the drive shaft 10 passes between the cylinder wall 7 and the crankshaft 4 and penetrates the internal combustion engine E, the internal combustion engine E and its accessories 14 are concentrated around the drive shaft 10. It can be arranged compactly. For this reason, in this embodiment, as shown in FIG. 5, a compact layout is realized in which the internal combustion engine E is accommodated in the existence range of the drive wheels T as viewed in the axial direction of the drive shaft 10.

  5 and 6, solid lines 11 and 18 indicate the positions of the engine hood and the engine room front wall according to the second embodiment, and broken lines 11A and 18A indicate the above-described single link type piston-crank mechanism. The positions of the engine hood and the engine room front wall according to the comparative example used are shown. According to the second embodiment, as compared with the comparative example, not only can the overall height of the internal combustion engine be lowered and the height of the engine hood 11 can be significantly reduced as in the first embodiment, as indicated by the arrow Y1, As indicated by the arrow Y2, the front overhang in front of the drive shaft 10 can be greatly reduced, and the engine room ER can be further downsized. In addition, in this embodiment, the position of the center of gravity of the internal combustion engine E having a large mass component in the vehicle can be made coincident with or very close to the center of the axle 10, so that the behavior when the vehicle turns head is further stabilized. Can do.

  The technical ideas that can be grasped from the above explanation are listed. However, the present invention is not limited to the configuration of the embodiment illustrated and described using reference numerals, and includes various modifications and changes without departing from the spirit of the present invention. The following (1) to (9) correspond to both the first and second embodiments, (10) corresponds to the first embodiment, and (11) corresponds to the second embodiment. ing.

  (1) A piston-crank mechanism 30 that mechanically links the piston 3 in the cylinder 6 and the crankpin 5 of the crankshaft 4 and converts the reciprocating linear motion of the piston 3 into rotational motion of the crankshaft 4 is provided. In the reciprocating internal combustion engine E, the rotation center 4 </ b> A of the crankshaft 4 is disposed on the side of the cylinder 6.

  (2) More specifically, the rotation center 4A of the crankshaft 4 is disposed within the existence range 6D of the cylinder 6 with respect to the engine vertical direction Fh.

  (3) Preferably, the piston-crank mechanism 30 is a rocker arm 31 that can swing around the fulcrum 1, a first link 32 that connects one end of the rocker arm 31 and the piston 3, and the other end of the rocker arm 31. And a second link 33 that connects the crankpin 5 of the crankshaft 4.

  (4) The link row composed of the first link 32, the rocker arm 31 and the second link 33 preferably has a substantially U-shape with the first link 32, the rocker arm 31 and the second link 33 as three sides. Yes.

  (5) Preferably, the position of the fulcrum 1 of the rocker arm 31 is changed to have a compression ratio variable means for changing the engine compression ratio. That is, a layout in which the crank center 4A is arranged on the side of the cylinder 6 described above is easily realized by using the multi-link type piston-crank mechanism 30 that can change the compression ratio.

  (6) The compression ratio variable means includes, for example, a control shaft 41, an actuator 43 that changes the rotational position of the control shaft 41, and a control eccentric shaft portion 42 that is provided eccentric to the control shaft 41. The rocker arm 31 is swingably attached to the control eccentric shaft portion 42.

  (7) Preferably, a head extension 8 </ b> A that defines a part of the crankcase 27 that houses the crankshaft 4 is integrally formed on the cylinder head 8 that covers the upper surface of the cylinder 6. As described above, by providing the cylinder head 8 with a function of forming a part of the crankcase 27, the configuration can be simplified and the cost can be reduced.

  (8) The effect of reducing the overall height of the engine according to the present invention is particularly useful for a series internal combustion engine in which a plurality of cylinders 6 are arranged in a line along the axial direction of the crankshaft 4 and the overall height of the engine is likely to be a problem. is there.

  (9) In the reciprocating internal combustion engine E in which the axial direction of the crankshaft 4 is mounted in a transverse posture along the vehicle width direction Fb in the engine room ER in front of the vehicle, the engine hood 11 is lowered by reducing the overall height of the engine. Since new effects such as improving the visibility by lowering the height position can be obtained, the present invention is particularly effective.

  (10) The cylinder wall 7 that defines the inner periphery of the cylinder 6 is provided, and a part of the cylinder wall 7 defines a part of the crankcase 27 that houses the crankshaft 4. Also good.

  (11) In the horizontal type internal combustion engine E described above, preferably, the drive shaft 10 to which the drive wheels T are connected at both ends passes between the first link 32 and the second link 33 and the reciprocating type. The internal combustion engine E is penetrated. In this case, the internal combustion engine E can be centrally arranged around the drive shaft 10, and effects such as a compact engine room ER can be obtained.

1 is a cross-sectional view schematically showing a reciprocating internal combustion engine according to a first embodiment of the present invention. Explanatory drawing which shows the link arrangement | positioning for every 90 degrees CA in the multiple link type piston-crank mechanism applied to the said reciprocating type internal combustion engine. FIG. 3 is a cross-sectional view schematically showing the reciprocating internal combustion engine according to the comparative example (A) and the first embodiment (B). Explanatory drawing which shows the link arrangement | positioning in a piston top dead center position and a piston bottom dead center position about each of the high compression ratio setting state and low compression ratio setting state of the said multiple link type piston-crank mechanism. The block diagram which shows simply the engine room carrying the reciprocating type internal combustion engine which concerns on 2nd Example of this invention. The block diagram which shows simply the engine room carrying the reciprocating type internal combustion engine which concerns on 2nd Example similarly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Piston 4 ... Crankshaft 5 ... Crankpin 6 ... Cylinder 7 ... Cylinder wall part 8 ... Cylinder head 10 ... Drive shaft 30 ... Piston-crank mechanism 31 ... Rocker arm 32 ... 1st link 33 ... 2nd link 41 ... Control shaft (Variable compression ratio means)
42 ... Control eccentric shaft (variable compression ratio means)
43 ... Actuator (variable compression ratio means)

Claims (8)

A piston-crank mechanism is provided that mechanically links the piston in the cylinder and the crankpin of the crankshaft and converts the reciprocating linear motion of the piston into the rotational motion of the crankshaft, and the output is taken out as the rotational motion of the crankshaft. In a vehicle equipped with a reciprocating internal combustion engine,
The center of rotation of the crankshaft is arranged on the side of the cylinder,
The piston-crank mechanism has a rocker arm that can swing around a fulcrum, an upper end that is connected to the piston by a piston pin so as to be relatively rotatable, and a lower end that is relatively rotatable to one end of the rocker arm by a first connecting pin. A first link to be connected, and a second link having an upper end connected to the crank pin in a relatively rotatable manner and a lower end connected to the other end of the rocker arm in a relatively rotatable manner by a second connecting pin ,
The reciprocating internal combustion engine is mounted in an engine room in front of the vehicle in a lateral orientation in which the axial direction of the crankshaft is along the vehicle width direction,
And a reciprocating internal combustion engine characterized in that a drive shaft having drive wheels connected to both ends passes between the first link and the second link and penetrates the reciprocating internal combustion engine . Vehicle . 2. A vehicle equipped with a reciprocating internal combustion engine according to claim 1, wherein the center of rotation of the crankshaft is disposed within a cylinder existing range in the engine vertical direction. The link row composed of the first link, the rocker arm, and the second link has a substantially U-shape having three sides of the first link, the rocker arm, and the second link. A vehicle comprising the reciprocating internal combustion engine according to 2. The reciprocating internal combustion engine according to any one of claims 1 to 3, further comprising compression ratio variable means for changing an engine compression ratio by changing a position of a fulcrum of the rocker arm. Vehicle . The compression ratio variable means includes a control shaft, an actuator that changes the rotational position of the control shaft, and a control eccentric shaft portion that is provided eccentric to the control shaft,
5. A vehicle equipped with a reciprocating internal combustion engine according to claim 4, wherein the rocker arm is swingably attached to the control eccentric shaft portion. 6. The cylinder head according to claim 1, further comprising: a cylinder head that covers an upper surface of the cylinder, the cylinder head having a head extension that defines a part of a crankcase that houses the crankshaft. A vehicle comprising the reciprocating internal combustion engine according to any one of the above. The vehicle having a reciprocating internal combustion engine according to any one of claims 1 to 6, wherein the plurality of cylinders are in-line internal combustion engines arranged in a line along the axial direction of the crankshaft. 2. A cylinder wall portion defining an inner periphery of the cylinder, and a part of the cylinder wall portion defines a part of a crankcase for accommodating the crankshaft. A vehicle including the reciprocating internal combustion engine according to any one of to 7 .

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