engine

Abstract

To provide an engine making a flow rate of intake air and strength of flowing compatible.SOLUTION: An engine 1 is equipped with ports 11 and 12 that communicates into a combustion chamber 40 to intake or exhaust air, valves 110 and 210 that open and close the ports, and turbulent flow generation members 120 and 220 provided on the valves. The valve has a valve body portion 111, and a valve stem 112 projecting out from the valve body portion. The turbulent flow generation member 120 has a turbulent flow generation plate 121 provided oppositely to the valve body portion, and a shaft-shaped portion 122 that projects out from the turbulent flow generation plate and is inserted into an opening provided in the valve stem so as to relatively displace in a longitudinal direction of the valve stem. The engine further has a turbulent flow generation member driving portion 300 that drives the turbulent generation member so as to separate the turbulent generation plate from the valve body portion of the valve in a direction paying out into the combustion chamber, at least in a compression step.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an engine which is a four-stroke reciprocating internal combustion engine.

Background Art

[0002] As a technique related to an intake device of an engine, for example, in Patent Document 1, as a structure of an intake port of an internal combustion engine that efficiently generates a tumble flow without reducing the flow coefficient, at a curved portion between a guide hole of a valve stem of the intake port and a valve seat portion, a build-up portion that gently changes the curvature convexly inward is provided on a centrifugal side wall surface located far from the center of curvature of the curvature. In Patent Document 2, while promoting the generation of a tumble flow, in the compression stroke, the tumble flow is crushed and subdivided into a large number of turbulent flows. Therefore, a recess is formed on the pressure receiving surface of the exhaust valve, and a turbulence generating means (resistor) such as an annular protrusion is formed in the recess. In Patent Document 3, in order to perform more reliable scavenging near the exhaust top dead center in the high rotation range and expand the squish area, an intake valve is composed of an outer valve and an inner valve movably inserted into the outer valve, and an exhaust valve is composed of an outer valve and an inner valve movably inserted into the outer valve. An inner passage opened and closed by the inner valve is formed in the outer valve. By a first cam and a second cam that control the opening and closing of the outer valve and the inner valve, at least during scavenging, the outer valves of the intake and exhaust valves are simultaneously closed in a non-overlap state, and the inner valves of the intake and exhaust valves are simultaneously opened in an overlap state. In Patent Document 4, in order to achieve both improvement of flow dimension and homogeneous air-fuel charge, in a valve mechanism of an internal combustion engine provided with a circular head composed of an inner valve and an outer valve, the inner valve is provided with a stem having a smaller outer diameter than the outer valve, and the outer valve is provided with a stem having a hollow portion for receiving the inner valve and a seat for seating the inner valve at the center of the bottom surface. Patent Document 5 describes providing a disturbance member on the piston that disrupts the tumble flow and generates turbulence in order to prevent the adverse effects caused by excessive tumble flow remaining in the combustion chamber and to improve combustion efficiency. The disturbance member is connected to a connecting rod by a link mechanism or the like and is configured to protrude only within a certain range when the piston is located near top dead center. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-184424 [Patent Document 2] Japanese Patent Publication No. 2017-115627 [Patent Document 3] Japanese Patent Publication No. 2007-211664 [Patent Document 4] Japanese Unexamined Patent Publication No. 7-77018 [Patent Document 5] Japanese Patent Publication No. 2013-155689 [Overview of the project] [Problems that the invention aims to solve]

[0004] In engine intake systems, the flow generated at the intake port (tumble ratio and turbulence intensity) and the flow coefficient μF are generally inversely related. In other words, if the intake port is designed with an emphasis on airflow, it is possible to increase the intake airflow in the high-load range and improve engine output. However, as a trade-off, the flow becomes weaker, which reduces the combustion speed in the low-load range (fuel-efficient range), and the deterioration of the isovolumetric ratio leads to a decrease in thermal efficiency and torque. In view of the above-mentioned problems, the object of the present invention is to provide an engine that achieves both intake airflow rate and flow strength. [Means for solving the problem]

[0005] To solve the above-mentioned problems, an engine according to one aspect of the present invention is characterized in that it comprises a port communicating with a combustion chamber for intake or exhaust, a valve for opening and closing the port, and a turbulence generating member provided on the valve, wherein the valve has a disc-shaped valve body and a valve stem protruding from the valve body, the turbulence generating member has a turbulence generating plate provided opposite to the valve body of the valve, and an axial portion protruding from the turbulence generating plate and inserted into an opening provided in the valve stem so as to be relatively displaceable along the longitudinal direction of the valve stem, and the engine further comprises a turbulence generating member drive unit that drives the turbulence generating member so that the turbulence generating plate moves away from the valve body of the valve in a direction toward being discharged into the combustion chamber, at least during the compression stroke of the engine. According to this, by causing a turbulence generating plate to protrude into the combustion chamber during the compression stroke, the airflow in the combustion chamber can be stirred, thereby promoting the flow of combustion air inside the cylinder. Furthermore, since it does not affect the flow path formed between the intake port and the valve body, it is possible to ensure intake airflow even under high load and high output conditions.

[0006] In the present invention, the turbulence generating plate can be configured as a disc-shaped member that is positioned along the surface of the valve body on the combustion chamber side when it is in close proximity to the valve body. According to this, when the turbulence generating plate is not made to protrude into the combustion chamber, by positioning the turbulence generating plate along the combustion chamber side surface of the valve body, the presence of the turbulence generating plate in strokes other than the compression stroke will not adversely affect other performance aspects.

[0007] In the present invention, the turbulence generating plate can be configured to have a plurality of openings formed that penetrate along the longitudinal direction of the axial portion. According to this, during the compression stroke, the airflow inside the cylinder is agitated as it passes through the opening, further promoting the flow of combustion air.

[0008] In the present invention, the turbulence generating member drive unit may be configured to include a cam follower that contacts a cam that drives the valve, and an interlocking member that drives the turbulence generating member in conjunction with the cam follower. According to this, it becomes possible to drive the turbulence generating member using the same cam as the valve, thereby reducing the number of steps required for machining the cam profile and simplifying the manufacturing process.

[0009] In the present invention, the turbulence generating member drive unit may be configured to have another cam provided coaxially with the cam that drives the valve. According to this, by driving the turbulence generating member using a cam profile different from that of the valve, the turbulence-promoting effect of the combustion air can be further improved. [Effects of the Invention]

[0010] As described above, the present invention provides an engine that achieves both intake airflow rate and flow strength. [Brief explanation of the drawing]

[0011] [Figure 1] This figure schematically shows the area around the combustion chamber in a first embodiment of an engine to which the present invention is applied. [Figure 2] This is a schematic diagram showing the configuration of the valve and turbulence generating member of the engine according to the first embodiment. [Figure 3] This diagram schematically shows the configuration of the intake valve drive mechanism in the first embodiment. [Figure 4] This diagram schematically illustrates an example of the correlation between the engine's flow coefficient and tumble ratio. [Figure 5] This figure schematically shows the configuration of the intake valve drive mechanism in a second embodiment of an engine to which the present invention is applied. [Figure 6] This diagram schematically shows the state transitions of the intake valve and the intake-side turbulence generating member in the engine of the second embodiment.

Mode for Carrying Out the Invention

[0012] <First Embodiment> Hereinafter, a first embodiment of an engine to which the present invention is applied will be described. The engine of the embodiment is, for example, a four-stroke gasoline engine mounted as a driving power source for an automobile such as a passenger car or a power generation power source for an electric vehicle.

[0013] FIG. 1 is a diagram schematically showing a peripheral portion of a combustion chamber in the engine of the first embodiment. FIG. 1(a) shows the state of the intake stroke, and FIG. 1(b) shows the state of the compression stroke. The engine 1 includes a cylinder head 10, a cylinder 20, a piston 30, a combustion chamber 40, an intake valve 110, an intake-side turbulence generating member 120, an exhaust valve 210, an exhaust-side turbulence generating member 220, and the like.

[0014] The cylinder head 10 is provided at an end portion of the cylinder 20 opposite to the crankshaft side (not shown). The cylinder head 10 is provided with an intake port 11, an exhaust port 12, an injector (not shown), a spark plug, and the like.

[0015] The intake port 11 is a flow path for introducing fresh air (combustion air) into the combustion chamber 40. The upstream end of the intake port 11 is connected to an intake device (not shown) having an intake duct, an air flow meter, a throttle valve, an intake manifold, and the like. The downstream end of the intake port 11 communicates with the inside of the combustion chamber 40.

[0016] The exhaust port 12 is a flow path for discharging exhaust gas (combusted gas) from the inside of the combustion chamber 40. The upstream end of the exhaust port 12 communicates with the inside of the combustion chamber 40. The downstream end of the exhaust port 12 is connected to an exhaust system (not shown) which includes an exhaust manifold, exhaust pipe, three-way catalytic converter, NOx reduction and storage catalyst, silencer, etc.

[0017] The cylinder 20 is a component having a cylindrical sleeve portion into which the piston 30 is inserted. The cylinder 20 is constructed by press-fitting a sleeve portion into the inner diameter side of an opening formed in the cylinder block. At the end of the cylinder 20 opposite to the cylinder head 10, there is a crankcase that houses a crankshaft (not shown), which is the output shaft of the engine 1. The cylinder head 10 and cylinder 20 are formed, for example, by performing predetermined machining on a casting made of an aluminum alloy.

[0018] The piston 30 is a cylindrical member inserted into the inner diameter side of the cylinder 20. The piston 30 is capable of relative displacement to the cylinder 20 along its axial direction. The crown surface of the piston 30 is positioned opposite the cylinder head 10 and forms part of the wall surface of the combustion chamber 40. The portion of the piston 30 opposite to the crown side is connected to the crankshaft via a connecting rod (not shown).

[0019] The combustion chamber 40 is a space inside the engine 1 where the fuel-air mixture is ignited and burned. The combustion chamber 40 is a space defined by the crown surface of the piston 30, the portion of the cylinder head 10 facing the crown surface of the piston 30, and the inner circumferential surface of the cylinder 20 between these.

[0020] The intake valve 110 and exhaust valve 210 are umbrella-shaped valves that open and close the intake port 11 and exhaust port 12 at predetermined valve timings. The intake valve 110 and exhaust valve 210 are driven by intake cams and exhaust cams (not shown), respectively, which rotate at half the rotational speed of the crankshaft. The configuration of the valve train drive mechanism will be explained in detail later.

[0021] The intake-side turbulence generating member 120 and the exhaust-side turbulence generating member 220 are provided on the intake valve 110 and the exhaust valve 210, respectively, and are components that have the function of promoting airflow (turbulence) within the combustion chamber 40. Here, since the intake valve 110 and the exhaust valve 210, and the intake-side turbulence generating member 120 and the exhaust-side turbulence generating member 220 have substantially similar configurations, the configurations of the intake valve 110 and the intake-side turbulence generating member 120 will be described in more detail below as representative examples.

[0022] Figure 2 shows the configuration of the intake valve and intake-side turbulence generating member in the engine of the first embodiment. Figure 2(a) is a view of the valve stem from the radial direction. Figure 2(b) is a view of the area indicated by the arrow bb in Figure 2(a). Figure 2(c) is a view of the cc section in Figure 2(a).

[0023] The intake valve 110 has a valve body 111 and a valve stem 112. The valve body 111 is a disc-shaped portion that closes the downstream end of the intake port 11 when the intake valve 110 is in the closed state (zero lift). The valve stem 112 is an axial portion that protrudes from the central part of the valve body 111 toward the cylinder head 10. The valve stem 112 is inserted into a stem guide, which is an opening formed in the cylinder head 10, so as to be displaceable relative to it along the axial direction. The valve stem 112 has a central portion that extends axially and has holes that open at both ends of the valve stem 112.

[0024] The intake-side turbulence generating member 120 has a turbulence generating plate 121 and a stem portion 122. The turbulence generating plate 121 is a plate-shaped member positioned opposite the combustion chamber side (lower side in Figure 2(a)) of the valve body 111 of the intake valve 110. The turbulence generating plate 121 is formed in a disc shape that is concentric with the valve body 111, as viewed from the axial direction of the valve stem 112.

[0025] The turbulence generating plate 121 is provided with a plurality of openings 123. The opening 123 is, for example, a circular hole that penetrates the turbulence generating plate 121 in the thickness direction (the axial direction of the valve stem 112). The openings 123 are arranged, for example, eight of them, at equal intervals along the circumferential direction of the turbulence generating plate. The stem portion 122 is an axial portion (shaft-shaped part) that protrudes from the central part of the turbulence generating plate 121 toward the cylinder head 10. The stem portion 122 is inserted into the hole in the valve stem 112 of the intake valve 110. The stem portion 122 is capable of relative displacement with respect to the intake valve 110 along the axial direction of the valve stem 112.

[0026] Figure 3 is a schematic diagram showing the configuration of the intake valve drive mechanism in the first embodiment. Figure 3(a) shows the state during the intake stroke. Figure 3(b) shows the state near bottom dead center after the intake stroke. Figure 3(c) shows the state during the compression stroke. In Figure 3, the lower side indicates the side of the combustion chamber 40.

[0027] The drive mechanism 300 that drives the intake valve 110 and the intake-side turbulence generating member 120 includes a cam 310, a rocker arm 320, a push rod 330, a valve lifter 340, a turbulence generating member lifter 350, a first valve spring 360, a second valve spring 370, and the like.

[0028] The cam 310 is positioned parallel to the crankshaft and is mounted on the camshaft, which rotates at half the speed of the crankshaft. The cam 310 has cam lobes (cam peaks) that drive the intake valve 110 in the opening direction at a predetermined valve opening time. Note that the shape of the cam 310 shown in Figure 3 is schematic and does not reflect the actual cam profile. (The same applies to Figures 5 and 6.)

[0029] The rocker arm 320 is a component that transmits the movement of the cam 310 to the push rod 330. For example, the rocker arm 320 is located on the side opposite to the combustion chamber 40 relative to the cam 310. The rocker arm 320 is supported in its intermediate portion so as to be able to swing around an axis parallel to the cam 310. One end of the rocker arm 320 is a cam follower that contacts the cam 310. The other end of the rocker arm 320 is positioned opposite the end of the push rod 330 that is not on the valve lifter 340 side.

[0030] The push rod 330 is an axial member that transmits the movement of the rocker arm 320 to the valve lifter 340. The pushrod 330 is pushed toward the combustion chamber 40 by the end of the rocker arm 320 when the cam lobe of the cam 310 presses against the rocker arm 320 and the rocker arm 320 oscillates. At this time, the rocker arm 320 transmits the input from the rocker arm 320 to the valve lifter 340 as axial force.

[0031] The valve lifter 340 is located at the end of the valve stem 112 of the intake valve 110 that is opposite to the valve body 111 side. When the valve lifter 340 is pressed toward the combustion chamber 40 by the push rod 330, it is displaced relative to the cylinder head 10 toward the combustion chamber, together with the intake valve 110 and the intake-side turbulence generating member 120. This causes lift in the intake valve 110, opening the end of the intake port 11. At this time, the intake-side turbulence generating member 120 moves relative to the cylinder head 10 in accordance with the intake valve 110, with the turbulence generating plate 122 in contact with the valve body 111.

[0032] The turbulence generating member lifter 350 is provided at the end of the stem portion 122 of the intake-side turbulence generating member 120 that is opposite to the turbulence generating plate 121. The tip of the stem portion 122 protrudes toward the cam 310 side relative to the tip of the valve stem 112. The turbulence generating member lifter 350 is pressed against the cam lobe of the cam 310, thereby pressing the stem portion 122 toward the combustion chamber and causing it to be displaced relative to the cylinder head 10. The turbulence generating member lifter 350 is an interlocking member of the present invention, and the contact surface portion with the cam 310 functions as a cam follower of the present invention.

[0033] The first valve spring 360 is a spring element sandwiched between the combustion chamber 40-side surface of the valve lifter 340 and a spring seat (not shown) provided on the cylinder head 10. The first valve spring 360 can be configured, for example, as a compression coil spring.

[0034] The second valve spring 370 is a spring element sandwiched between the surface of the valve lifter 340 opposite to the combustion chamber 40 and the turbulence generating member lifter 350. The second valve spring 370 can be configured, for example, as a compression coil spring. The drive mechanism described above is also provided on the exhaust valve 210 and the exhaust-side turbulence generating member 220, except for the valve opening timing. The drive mechanism functions as a drive unit for the turbulence generating member of the present invention.

[0035] The operation of the engine in the first embodiment will be described below. First, as shown in Figure 3(a), during the intake stroke, the cam lobe of the cam 310 presses against the rocker arm 320, causing the intake valve 110 to open. At this time, the piston 30 moves away from the cylinder head 10 (towards the bottom dead center). This allows fresh air (combustion air) to be introduced from the intake port 11 into the combustion chamber 40 (inside the cylinder). (The flow of fresh air is shown by arrows in Figure 1(a).) At this time, the turbulence generating member lifter 350 is separated from the cam 310.

[0036] At this time, the intake-side turbulence generating member 120 is displaced in accordance with the intake valve 110. During the intake stroke, the turbulence generating plate 121 is in contact with the valve body 111 of the intake valve 110. Furthermore, the exhaust valve 210 is closed, and the turbulence generating plate 221 of the exhaust-side turbulence generating member 220 is in contact with the valve body 211 of the exhaust valve 210.

[0037] Next, as shown in Figure 3(b), near the bottom dead center at the end of the intake stroke, the intake valve 110 is closed, and the turbulence generating plate 121 of the intake-side turbulence generating member 120 is in contact with the valve body 111 of the intake valve 110. Furthermore, the exhaust valve 210 is closed, and the turbulence generating plate 221 of the exhaust-side turbulence generating member 220 is in contact with the valve body 211 of the exhaust valve 210. At this time, both the rocker arm 320 and the turbulence generating member lifter 350 are in contact with the base circular portion of the cam 310.

[0038] As shown in Figure 3(c), during the compression stroke, both the intake valve 110 and the exhaust valve 210 are closed. At this time, the piston 30 moves in a direction toward the cylinder head 10 (towards the compression top dead center). As a result, the fresh air in the combustion chamber 40 is compressed. At this time, the rocker arm 320 is in contact with the base circular portion of the cam 310, and the turbulence generating member lifter 350 is pressed by the cam lobe of the cam 310.

[0039] Furthermore, during the compression stroke, the intake-side turbulence generating member 120 and the exhaust-side turbulence generating member 220 are displaced (lifted) relative to the intake valve 110 and the exhaust valve 210 in a direction that protrudes into the combustion chamber 40. As a result, a portion of the fresh air compressed by the piston 30 collides with the intake-side turbulence generating member 120 and the exhaust-side turbulence generating member 220, and is stirred as it passes through the opening 123 and similar openings formed in the exhaust-side turbulence generating member 220, thereby promoting airflow (turbulence) within the combustion chamber 40. (In Figure 1(b), the flow of fresh air is indicated by arrows.)

[0040] Figure 4 schematically shows an example of the correlation between the engine's flow coefficient and tumble ratio. In Figure 4, the horizontal axis represents the tumble ratio (turbulence intensity) in the combustion chamber, and the vertical axis represents the flow coefficient (a coefficient proportional to the reciprocal of the airflow resistance). As shown in Figure 4, a larger tumble ratio improves the combustion speed at low loads and improves the isovolumetric ratio, resulting in improved thermal efficiency and a tendency towards lower fuel consumption for the engine. On the other hand, the larger the flow coefficient, the greater the intake airflow at high loads, and the more powerful the engine tends to be.

[0041] Generally, the tumble ratio and the flow coefficient are inversely related, as illustrated by the dashed line in Figure 4. For example, if the intake port is made into a straight shape with low airflow resistance in order to increase the flow coefficient and thus increase power output, the tumble ratio will decrease, resulting in poor fuel efficiency. The comparative example shown in the figure illustrates a typical engine that does not have a turbulence generating element like the one in the first embodiment. In contrast, in the first embodiment, the intake-side turbulence generating member 120 and the exhaust-side turbulence generating member 220 are projected into the combustion chamber 40 during the compression stroke, stirring the fresh air during compression. This promotes turbulence within the combustion chamber, enabling a balance between fuel efficiency and performance, even when the shape of the intake port is adjusted to favor a favorable flow coefficient.

[0042] According to the first embodiment described above, the following effects can be obtained. (1) By causing the turbulence generating plate 122 (and the turbulence generating plate of the exhaust-side turbulence generating member 220) to protrude into the combustion chamber 40 during the compression stroke, the airflow in the combustion chamber 40 can be stirred, thereby promoting the flow of fresh air in the cylinder 20. Furthermore, since it does not affect the flow path formed between the intake port 11 and the valve body 111 of the intake valve 110, it is possible to ensure intake airflow even under high load and high output conditions. (2) When the disc-shaped turbulence generating plate 122 (and the turbulence generating plate of the exhaust-side turbulence generating member 220) is not made to protrude into the combustion chamber 40 (except during the compression stroke), the turbulence generating plate 122 is positioned along the surface of the valve body 111 of the intake valve 110 that faces the combustion chamber 40, so that the presence of the turbulence generating plate 122 does not adversely affect other performance during strokes other than the compression stroke. (3) By providing openings in the turbulence generating plates of the turbulence generating members 120 and 220, the airflow inside the cylinder 20 is stirred as it passes through the openings during the compression stroke, further promoting the flow of fresh air. (4) By configuring the drive mechanism 300 to include a cam follower that contacts a cam 310 that drives the intake valve 110, and a turbulence generating member lifter 350 that drives the intake side turbulence generating member 120 in conjunction with the cam follower, it becomes possible to drive the intake side turbulence generating member 120 using the same cam 310 as the intake valve 110, thereby reducing the number of steps required for machining the cam profile and simplifying the manufacturing process.

[0043] <Second Embodiment> Next, a second embodiment of an engine to which the present invention is applied will be described. In the second embodiment, the same reference numerals are used for parts common to the first embodiment described above, and their descriptions are omitted. The differences will be explained in detail.

[0044] Figure 5 is a schematic diagram showing the configuration of the intake valve drive mechanism in the engine of the second embodiment. Figure 5(a) is a schematic cross-sectional view taken through a plane containing the central axis of the camshaft and valve stem. Figure 5(b) is a view of the section bb in Figure 5(a). Figure 5(c) is a view of the cc section in Figure 5(a). In the engine of the second embodiment, the intake valve 110 and the intake-side turbulence generating member 120 are each driven by independent cams arranged axially on the same camshaft. (The same applies to the exhaust valve 210 and the exhaust-side turbulence generating member 220.)

[0045] The drive mechanism 400 that drives the intake valve 110 and the intake-side turbulence generating member 120 includes a first cam 410, a second cam 420, a valve lifter 430, a turbulence generating member lifter 440, a first valve spring 450, a second valve spring 460, and the like.

[0046] The first cam 410 is positioned parallel to the crankshaft and is mounted on a camshaft S that rotates at half the speed of the crankshaft. The first cam 410 has a cam lobe that drives the intake valve 110 in the opening direction at a predetermined valve opening time. The first cam 410 can be installed in, for example, two locations per intake valve 110, sandwiching the second cam 420 in the axial direction of the camshaft S.

[0047] The second cam 420 is positioned coaxially with the first cam 410 on the camshaft S. The second cam 420 has a cam lobe that drives the intake-side turbulence generating member 120 in the opening direction at a predetermined time. The second cam 420 can be positioned, for example, between a pair of first cams 410.

[0048] The valve lifter 430 is located at the end of the valve stem 112 of the intake valve 110 that is opposite to the valve body 111 side. When the valve lifter 430 is pressed toward the combustion chamber 40 by the cam lobe of the first cam 410, it is displaced relative to the cylinder head 10 toward the combustion chamber, together with the intake valve 110 and the intake side turbulence generating member 120. This causes lift in the intake valve 110, opening the end of the intake port 11. At this time, the intake-side turbulence generating member 120 moves relative to the cylinder head 10 in accordance with the intake valve 110, with the turbulence generating plate 122 in contact with the valve body 111.

[0049] The turbulence generating member lifter 440 is provided at the end of the stem portion 122 of the turbulence generating member 120 that is opposite to the turbulence generating plate 121 side. The tip of the stem portion 122 protrudes toward the cam 310 side relative to the tip of the valve stem 112. The turbulence generating member lifter 440 is pressed by the cam lobe of the second cam 420, thereby pressing the stem portion 122 toward the combustion chamber and causing it to be displaced relative to the cylinder head 10.

[0050] The first valve spring 450 is a spring element sandwiched between the combustion chamber 40-side surface of the valve lifter 430 and a spring seat (not shown) provided on the cylinder head 10. The first valve spring 450 can be configured, for example, as a compression coil spring.

[0051] The second valve spring 460 is a spring element sandwiched between the surface of the valve lifter 430 opposite to the combustion chamber 40 and the turbulence generating member lifter 440. The second valve spring 460 can be configured, for example, as a compression coil spring. The drive mechanism described above is also provided on the exhaust valve 210 and the exhaust-side turbulence generating member 220, except for the valve opening timing.

[0052] Figure 6 is a schematic diagram showing the state transitions of the intake valve and intake-side turbulence generating member in the engine of the second embodiment. Figure 6(a) shows the state during the intake stroke. Figure 6(b) shows the state near bottom dead center after the intake stroke. Figure 6(c) shows the state during the compression stroke. In Figure 6, the lower side indicates the side of the combustion chamber 40.

[0053] In the second embodiment, the valve lifter 430 and the turbulence generating member lifter 440 are driven directly (so-called direct hit) by independent cams 410 and 420, respectively. However, when focusing on the operation of the intake valve 110 and the intake-side turbulence generating member 120, it can be seen that it is the same as in the first embodiment. In the second embodiment, by making the cams 410 and 420 independent, it is also possible to configure the cam profile of the cam 420 that drives the intake-side turbulence generating member 120 to be different from the cam profile of the cam 410 in order to optimize the turbulence generation effect.

[0054] According to the second embodiment described above, the same effects as those of the first embodiment (excluding the effects described in section (4)) can be obtained, and furthermore, by driving the turbulence generating member using a cam profile different from that of the valve, the turbulence promotion effect of the combustion air can be further improved.

[0055] (modified version) The present invention is not limited to the embodiments described above, and various modifications and changes are possible, all of which fall within the technical scope of the present invention. (1) The configuration of the engine, turbulence generating member, valve, drive mechanism, etc., is not limited to the embodiments described above and can be modified as appropriate. (2) In each embodiment, the turbulence generating member is kept lifted at all times regardless of the engine's operating range. However, the present invention is not limited to this, and the turbulence generating member may be lifted only in some operating ranges and stopped in other ranges. For example, during the catalyst warm-up period immediately after a cold start of the engine, the turbulence generating component may be deliberately stopped in order to slow down combustion and raise the exhaust gas temperature. Such operation can be easily achieved by someone skilled in the art, for example, by adapting the configuration of a cam switching mechanism, which is well known in variable valve timing mechanisms. (3) In each embodiment, the turbulence generating member is lifted only during the compression stroke, but the start time of the lift of the turbulence generating member may be near the end of the intake stroke. Also, the end time of the lift of the turbulence generating member may be near the start of the combustion stroke. (4) In each embodiment, the turbulence generating member is provided on both the intake valve and the exhaust valve, but it is also possible to configure the turbulence generating member to be provided on only one of the intake valve or the exhaust valve, or to configure the turbulence generating member to be provided on only some of the intake valves or some of the exhaust valves. [Explanation of Symbols]

[0056] 1 engine, 10 cylinder heads 11 Intake port 12 Exhaust port 20 cylinders, 30 pistons 40 Combustion chamber 110 Intake valve 111 Valve body 112 Valve stem 120 Intake side turbulence generating member 121 Turbulence generating plate 122 Stem section 123 Aperture 210 Exhaust valve 220 Exhaust-side turbulence generating member 300 Drive mechanism (first embodiment) 310 Cam 320 Rocker arm 330 Push rod 340 Valve Lifter 350 Turbulence Generating Member Lifter 360 First valve spring 370 Second valve spring 400 Drive mechanism (second embodiment) 410 First cam 420 Second cam 430 Valve lifter 440 Turbulence generating member lifter 450 First valve spring 460 2nd valve spring S camshaft

Claims

1. A port that communicates with the combustion chamber and performs intake or exhaust, A valve for opening and closing the aforementioned port, An engine comprising a turbulence generating member provided on the valve, The aforementioned valve is A disc-shaped valve body, It has a valve stem protruding from the valve body portion, The turbulence generating member is A turbulence generating plate is provided opposite the valve body of the valve, It has a shaft-like portion that protrudes from the turbulence generating plate and is inserted into an opening provided in the valve stem so as to be displaceable relative to the valve stem along the longitudinal direction, The aforementioned engine is The system further includes a turbulence generating member drive unit that drives the turbulence generating member so that the turbulence generating plate moves away from the valve body of the valve in a direction that is ejected into the combustion chamber, at least during the compression stroke of the engine. An engine characterized by the following.

2. The turbulence generating plate is a disc-shaped member that, when in close proximity to the valve body, is positioned along the surface of the valve body facing the combustion chamber. The engine according to claim 1, characterized by the following:

3. The turbulence generating plate has a plurality of openings formed that penetrate along the longitudinal direction of the axial portion. The engine according to claim 1 or claim 2, characterized by the following:

4. The turbulence generating member drive unit is A cam follower that contacts the cam that drives the valve, The cam follower has an interlocking member that drives the turbulence generating member in conjunction with the cam follower. The engine according to claim 1 or claim 2, characterized by the above.

5. The turbulence generating member drive unit is The valve has another cam that is coaxially mounted with the cam that drives the valve. The engine according to claim 1 or claim 2, characterized by the following:

Images