JP4085923B2 - V type engine - Google Patents

Description

  The present invention relates to a V-type engine that takes into account the layout of precision functional components with limited vibration resistance.

  In many passenger cars (vehicles), a V-type engine is mounted in order to be easy to mount although it is a multi-cylinder engine.

  Many V-type engines use a structure in which a cylinder block having a V-shaped deck cylinder, a cylinder head, and a head cover are combined. And, as the piston reciprocates in the cylinder formed in each deck cylinder part, a combustion cycle that repeats intake, compression, explosion, and exhaust is formed, and the obtained power is output from the crankshaft. is there.

  Many of these V-type engines have an electronic throttle valve and electronic EGR that are assembled to the intake system near the top of the bank protruding in a V shape due to the relationship with surrounding parts and layout. Precise functional parts such as valves are arranged. Since such precision functional parts are configured using precision parts and electronic parts, vibration resistance is limited. For this reason, it is susceptible to large vibrations and shocks input from the outside.

  However, when the engine is operated, roll vibration occurs. In the case of a V-type engine, roll vibration is generated in the roll direction around a roll vibration center existing in the vicinity between the bank bases. The amplitude and acceleration of roll vibration are generally proportional to the distance from the roll vibration center. For this reason, if a precision functional component is simply arranged near the top of the bank that is far away from the center of roll vibration, durability of the precision functional component may be reduced by roll vibration.

  Therefore, it is conceivable to move the precision functional component downward from the current installation point. However, precision functional parts are installed near the current bank head for reasons such as engine size reduction, layout restrictions, interaction with equipment around the engine, and avoiding interference with other equipment. It is difficult to change the installation location.

On the other hand, for a V-type engine, a technique has been proposed in which the entire engine is made compact by using a structure in which the cylinder axis is offset from the center of the crankshaft. This is because the cylinder axis of each deck cylinder is offset from the center of the crankshaft to the direction of rotation of the crankshaft, and each deck cylinder is moved along the cylinder axis to the center of the crankshaft to move from the center of the crankshaft to the bottom end surface of the cylinder. This is a technique for shortening the length (cylinder surface height) (see, for example, Patent Document 1).
JP-A-3-281901

  By applying this technique, it is conceivable to bring the position near the top of the bank where the precision functional parts are arranged closer to the roll vibration center. However, this structure requires a large change in many parts of the engine in order to bring each deck cylinder to the center of the crankshaft along the cylinder axis. Moreover, when each deck cylinder is moved along the cylinder axis to the center of the crankshaft, the bottom surface of one deck cylinder enters the inside of the other deck cylinder and interferes with the connecting rod. A considerable burden is imposed both in terms of structure and cost.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a V-type engine that has a simple and low cost burden and can improve the durability and reliability of precision functional parts.

In order to achieve the above object, the cylinder main body is configured such that each bank is offset in the same direction as the rotation direction of the crankshaft, and a surge is formed above the open portion between the plurality of banks. A tank is disposed, and a plurality of branch-like intake manifolds are formed in the lower part of the surge tank, and each of the intake manifolds is connected to an intake port of each cylinder head on the inner side of each bank, and the offset lower with air inlet of the bank offset to the side is located lower than the inlet of the bank shifted to the higher side, the throttle valve is disposed in overhead near the bank shifted to the low side, the throttle valve by A configuration is adopted in which the lower end of each is disposed at a position lower than the upper end of the bank shifted to the higher side .

The invention according to claim 2 is configured such that each bank is offset in the same direction as the rotation direction of the crankshaft, a surge tank is disposed above the bank raised by the offset, and a lower part of the surge tank includes: A plurality of branch-like intake manifolds are formed,
Each of the intake manifolds is connected to an intake port of each cylinder head on the inner side of each bank, and the intake port of the bank shifted to the lower side due to the offset is more than the intake port of the bank shifted to the higher side In addition to being arranged low, the inlet pipe portion of the surge tank is arranged above the bank lowered by the offset from the direction intersecting the cylinder row direction,
A throttle valve is connected to the end of the inlet pipe portion arranged above the head, and the lower end of the throttle valve is arranged at a position lower than the upper end of the bank shifted to the higher side .

  According to the present invention, a precision functional component with a limited vibration resistance is provided near the center of the engine body with a simple and low-cost structure in which each bank is offset in the same direction as the rotation direction of the crankshaft. It can be arranged at a point near the existing roll vibration center.

  As a result, the amplitude and vibration acceleration of roll vibration input to the precision functional component can be reduced, and the durability reliability of the precision functional component can be improved. It is particularly suitable for precision functional parts assembled in the intake system, such as throttle valves and EGR valves that require durability and reliability.

[First Embodiment]
Hereinafter, the present invention will be described based on a first embodiment shown in FIGS.

  FIG. 1 is a front sectional view of a multi-cylinder V-type engine, for example, a 6-cylinder V-type engine 5 to which the present invention is applied, for example, for vehicle travel, and FIG. 2 is a plan view of the engine 5 (in FIG. FIG. 3 is a side view of the engine 5 (a view taken along line III-III in FIG. 1).

  In these drawings, reference numeral 5 a denotes the engine body of the V-type engine 5. As shown in FIG. 4, the engine main body 5a has, for example, a V-shaped cylinder block, specifically, a common crankcase portion 6 at the lower portion, and six cylinders 7 at the upper portion, for example, three each. Cylinder block 9 having a V-shaped deck cylinder portion 8 distributed to a line of cylinders, a cylinder head 10 mounted on the head for each deck cylinder portion 8, and a head for each cylinder head 10 A rocker cover 11 (cover member) mounted so as to close the opening, an oil pan 12 mounted so as to cover the lower opening of the crankcase portion 6 and the like are combined. And the bank 13a, 13b which protrudes in V shape from the combination of each deck cylinder part 8, the cylinder head 10, and the rocker cover 11 is comprised.

  A crankshaft 15 extending along the engine full length direction is rotatably supported in the crankcase portion 6. Pistons 18 housed in the cylinders 7 are rotatably connected to the respective parts of the crankshaft 15 via connecting rods 16. Each cylinder head 10 includes, for each cylinder 7, for example, a suction / exhaust valve, a valve mechanism for a suction / exhaust valve, a spark plug, and an injector (none of which are shown). By operating the valve and the spark plug at a predetermined timing, a combustion cycle that repeats an intake stroke, a compression stroke, an explosion stroke, and an exhaust stroke is performed. Arrow A indicates the direction of rotation of the crankshaft 15 during this operation.

  The banks 13a and 13b of the V-type engine 5 are offset in the same direction as the rotation direction of the crankshaft 15 (arrow A direction).

  Explaining this point, as shown in FIG. 4, in the normal engine (V-type engine in which each bank is not offset), the axis L1 of the cylinder 7 in each deck cylinder portion 8 (bank 13a, 13b) It is in a position that passes through the axial center O of the shaft 15. The two-dot chain line in FIG. 4 shows the outer shape of the banks 13a and 13b of this normal engine. The offset V-type engine 5 maintains the deck height H represented by the length from the axial center O of the crankshaft 15 to the deck surface of the cylinder block 9, while maintaining the deck height 8 of each deck cylinder portion 8 (banks 13 a, 13 b). Each deck is translated by moving the axis L1 in the same direction as the rotation direction of the crankshaft 15 (the direction of arrow A) with respect to the axis O of the crankshaft 15 to the position of the axis L as an offset point as indicated by the arrow B. The cylinder part 8 (banks 13a and 13b) is shifted in the same direction as the rotation direction of the crankshaft 15 (while maintaining the bank angle) (offset). δ represents the offset amount at that time. In the present embodiment, each axis L of the plurality of cylinders 7 constituting the bank 13 a exists in a plane parallel to the crankshaft 1. The same applies to the bank 13b. The deck heights H of both banks 13a and 13b are set equal.

  Due to this offset, the front deck cylinder portion 8 (bank 13b side) in the crank rotation direction A has a lower vertical dimension by C1 than the normal engine, and the rear deck cylinder portion 8 (bank 13a side). The height in the vertical direction is higher by C2 than in the case of a normal engine, and the height of the cylinder heads 6 of both decks is greatly different in the degree of C (= C1 + C2). C1 and C2 can be obtained by using SIN (θ / 2) × δ, respectively. However, (theta) shows a bank angle. Specifically, for example, when the bank angle θ is 60 °, the vertical height of the deck cylinder portion 4 changes roughly at a value equal to the offset amount δ.

  By using the offset banks 13a and 13b, an intake system 20 is assembled as shown in FIGS.

  Here, for example, a type in which a surge tank 22 is disposed so as to cover the upper side of the opening 14 between the banks 13a and 13b is used for the intake system 20. Explaining the same type, a plurality of branch-like intake manifolds 21 are formed below the surge tank 22. Further, as shown in FIGS. 2 and 3, an inlet pipe portion 22a is formed in a part of the surge tank 22, for example, in the center of the side portion of the surge tank 22 on the bank 13b side. Each intake manifold 21 is connected to an intake port (not shown) of each cylinder head 10 on the inner side (facing side) of each bank 13a, 13b. As shown in FIGS. 2 and 3, the inlet pipe portion 22a extends above the bank 13b (directly above) to the rear of the engine along the cylinder row direction (direction in which the cylinders are arranged). The end portion of the inlet pipe portion 22a slightly protrudes from the rear end of the bank 13b, as in the case of a normal engine (V-type engine in which each bank is not offset). At the end (inlet) of the inlet pipe portion 22a, a throttle valve (corresponding to the precision functional part of the present application), for example, an electronic throttle valve, is provided in the same manner as a normal engine (V-type engine in which each bank is not offset). 23 is connected. That is, the electronic throttle valve 23 is arranged near the overhead of the bank 13b with the same layout as that of the normal engine. With this connection, air necessary for combustion is sucked into the combustion chamber through the throttle valve 23, the surge tank 22, and the intake manifold 21. It is also conceivable that only the throttle valve 23 is moved in the vertical direction with respect to the inlet pipe portion 22a to bring the throttle valve 23 closer to a roll vibration center G described later. However, it is necessary to abruptly bend the vicinity of the connection point of the throttle valve 23 of the inlet pipe portion 22a, which is not preferable because the intake resistance increases.

  Further, as shown in FIGS. 2 and 3, an EGR system 24 for returning the exhaust gas discharged from the V-type engine 5 to the intake side is connected to the downstream side of the electronic throttle valve 23, for example, the inlet pipe portion 22a. Has been. The EGR system 24 includes an EGR passage 25 that bypasses between an exhaust system (not shown) of the engine body 5a and the inlet pipe portion 22a, as in a normal engine (a V-type engine in which each bank is not offset). Combined with an electronic EGR valve 26 (equivalent to the precision functional part of the present application) using, for example, a solenoid connected to an outlet of the EGR passage 25, for example, an outlet port (not shown) formed on the peripheral wall of the inlet pipe portion 22a The structure is used. That is, the exhaust gas can be returned to the intake system through the EGR passage 25 and the EGR valve 26.

  As a result, the throttle valve 23 and the EGR valve 26 (both precision functional parts), which have limited vibration resistance, both have the same layout as that of the normal engine, that is, the layout that protrudes from the upper end of the bank 13b. The center of the roll vibration of the engine main body 5a generated by the engine operation, that is, the roll vibration center G existing in the vicinity of the engine center when the engine main body 5a is viewed from the front using the bank 13b which is lowered by the offset. Placed as close as possible. As a result, the distance R from the throttle valve 23 to the roll vibration center G is shortened as compared with the normal engine as shown in FIG. 1 without forcing the change of the throttle valve position and the EGR valve position, which are considered difficult. be able to. Of course, the distance R from the EGR valve 26 to the roll vibration center G is also shorter than that of the normal engine.

  Therefore, with a simple structure using offset, the amplitude of roll vibration and the vibration acceleration of roll vibration centered on the roll vibration center G input to the throttle valve 23 and the FGR valve 26 can be reduced. The durability reliability of the valve 26 can be improved. This is particularly effective for the electronic throttle valve 23 and the electronic EGR valve 26 with limited vibration resistance. Further, since the axis L of the cylinder 7 is offset in the same direction as the rotation direction of the crankshaft 15 (the direction of arrow A), a known effect that the thrust force that the piston 18 receives in the explosion stroke is reduced.

[Second Embodiment]
FIG. 5 shows a second embodiment of the present invention.

  This embodiment shows an example using an intake system 30 having a layout different from that of the first embodiment. In the intake system 30, the surge tank 22 is disposed above the bank 13a which is raised by the offset, and the inlet pipe portion 22a of the surge tank 22 is lowered by the offset from the direction intersecting the cylinder row direction. The electronic throttle valve 23 is connected to the end of the inlet pipe disposed above the head 13b.

  Even in the intake system 30 in which the throttle valve 23 is arranged above the bank 13b, as in the first embodiment, the same layout as that of the normal engine is maintained and the bank 13b having a lower offset is used. The distance R from the throttle valve 23 to the roll vibration center G can be made shorter than that of a normal engine.

  However, in the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[ Reference example ]
FIG. 6 shows a reference example of the present invention.

This reference example shows an example using an intake system 31 having a layout different from those of the first and second embodiments. In this intake system 31, the surge tank 22 is disposed above the bank 13b lowered by the offset, and an electronic throttle valve 23 is connected to an inlet port (not shown) formed on the side of the surge tank 22. This is the structure.

  In the intake system 31 in which the throttle valve 23 is arranged so as to protrude from the upper side of the bank 13b, as in the first embodiment, the layout remains the same as that of the normal engine, and the offset becomes low. Using the bank 13b, the distance R from the throttle valve 23 to the roll vibration center G can be made shorter than that of a normal engine.

However, in the reference example , the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

The present invention is not limited to the first and second embodiments described above, and various modifications may be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the left and right banks are offset by the same offset amount. However, both offset amounts may be different within a range that does not affect the engine performance.

1 is a front sectional view showing a V-type engine according to a first embodiment of the present invention. FIG. 2 is a plan view of a V-type engine taken along line II to II in FIG. 1. The side view of the V type engine which follows the III-III line in FIG. Sectional drawing for demonstrating the offset in each bank of the V type engine. Sectional drawing which shows the principal part of the 2nd Embodiment of this invention. Sectional drawing which shows the principal part of the reference example of this invention.

Explanation of symbols

  5 ... V-type engine, 5a ... engine body, 13a, 13b ... bank, 15 ... crankshaft, 21 ... intake manifold, 22 ... surge tank, 23, 26 ... electronic throttle valve, electronic EGR valve (precision function) Parts), L ... axis of the cylinder, O ... center of the crankshaft.

Claims (2)

A V-type engine having an engine main body formed with a plurality of banks protruding in a V shape by sorting cylinders,
The engine body is configured by offsetting each bank in the same direction as the rotation direction of the crankshaft,
A surge tank is disposed above the opening between the plurality of banks;
A plurality of branch-like intake manifolds are formed at the bottom of the surge tank,
Each intake manifold is connected to an intake port of each cylinder head on the inner side of each bank,
The inlet of the bank shifted to the lower side due to the offset is disposed lower than the inlet of the bank shifted to the higher side,
A V-type engine, characterized in that a throttle valve is disposed near the overhead of the bank shifted to the lower side, and a lower end of the throttle valve is positioned lower than an upper end of the bank shifted to the higher side . A V-type engine having an engine body formed with a plurality of banks protruding in a V shape by sorting cylinders,
The engine body is configured by offsetting each bank in the same direction as the rotation direction of the crankshaft,
A surge tank is placed above the bank raised by the offset,
A plurality of branch-like intake manifolds are formed at the bottom of the surge tank,
Each intake manifold is connected to an intake port of each cylinder head on the inner side of each bank,
The inlet of the bank shifted to the lower side due to the offset is disposed lower than the inlet of the bank shifted to the higher side,
The inlet pipe portion of the surge tank is arranged above the bank lowered by the offset from the direction intersecting the cylinder row direction,
A V-type engine characterized in that a throttle valve is connected to an end of the inlet pipe portion arranged above the head, and a lower end of the throttle valve is arranged at a position lower than an upper end of the bank shifted to the high side. .

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