JPH0143128B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a multi-cylinder internal combustion engine using rotary valves. [Prior Art] In a multi-cylinder internal combustion engine using rotary valves, ideal valve opening/closing timing can be obtained.
On the other hand, there were problems such as the complexity of the mechanism, the airtightness of the valve, and the durability of the sliding parts. For example, JP-A-50-125115 (Conventional Example 1) describes a rotary valve internal combustion engine equipped with a timing device, and the full text of Utility Model Application Laid-Open No. 55-180040 (Conventional Example 2) describes an internal combustion engine equipped with a timing device. The idea of installing a rotary valve in the intake port upstream of the intake valve was developed by Jikosho.
No. 37-17407 (Conventional Example 3) discloses a device that adjusts the opening area to the intake valve body according to the engine speed, as disclosed in Japanese Patent Application Laid-Open No. 55-57646 (Conventional Example 4).
The structure in which ceramic is arranged in the compression chamber of the combustion chamber is also disclosed in Utility Model Application Publication No. 56-45105 (conventional example 5).
Each of these describes an idea in which ceramic is protruded from the outer periphery of a rotary valve. [Problems to be Solved by the Invention] However, each of the conventional examples has the following points. In Conventional Example 1, there is no concept of using ceramic for the rotary valve due to its structure, and it is difficult to fully exhibit the characteristics of the rotary valve. Conventional Example 2 does not have a rotary valve in the exhaust port, and the shape of the rotary valve is not specified, so stable engine combustion cannot be achieved over the entire engine speed range and load range. . Conventional Example 3 focuses only on increasing or decreasing the air intake area of the engine's intake valve according to the engine rotational speed so that the air supply ratio is almost the maximum at each rotational speed, and there is no suggestion regarding the use of ceramics. It has not been. In Conventional Example 4, only a portion of the cylinder head and the valve body are made of ceramic, and the rotary valve is not included in the constituent elements. Therefore, it is impossible to make that part into ceramic. Conventional Example 5 is an idea related to improving heat resistance, and even if a rotary valve with such a structure is made of ceramic, the effect similar to that of the present invention cannot be obtained. The purpose of the present invention is to have a simple structure and be easily made of ceramic, to be able to adjust ideal valve opening/closing timing and valve opening time according to vehicle running conditions such as vehicle speed and throttle opening, and to maintain valve airtightness and durability of sliding parts. To provide a ceramic rotary valve type multi-cylinder internal combustion engine with a valve body displacement mechanism, which is excellent in performance. [Means for Solving the Problems] In order to achieve the above object, the ceramic rotary valve type multi-cylinder internal combustion engine with a valve body displacement mechanism of the present invention employs the following configuration. The first invention provides (a) an intake hole and an exhaust hole formed in the side wall, communicating with all of the intake hole, exhaust hole, and combustion chamber in the longitudinal direction, and forming one straight hole having a circular cross section. , (b) a ceramic cylinder head main body in which the connection surface between the straight hole and the intake/exhaust hole is formed in an elliptical shape with a radius that gradually changes along the central axis of the straight hole; Each curved hole is fitted into the straight hole rotatably and slidably in the axial direction, and the intake curved hole communicates the combustion chamber and the intake hole within a predetermined crank rotation angle range, and the exhaust (c) The curved hole for the ceramic rotary valve body connects the exhaust hole and the combustion chamber in a predetermined rotation angle range, and It consists of a valve body displacement mechanism that displaces the valve body in the axial direction so as to control the communication area of the hole to each curved hole and the valve opening timing. A second invention provides (a1) a first straight hole that is formed in the longitudinal direction of an intake hole and an exhaust hole formed in the side wall and communicates the intake hole and the combustion chamber, and that has a circular cross section; A second straight hole having a circular cross section is formed and communicates with the exhaust hole and the combustion chamber. (b1) A ceramic cylinder head body formed in an elliptical shape with a radius that gradually changes along the central axis of the straight hole; The curved hole for intake communicates the combustion chamber and the intake hole within a predetermined range of crank rotation angles, and the curved hole for exhaust connects within other predetermined rotation angle ranges. (c) A ceramic rotary valve body that connects the exhaust hole and the combustion chamber, and (c) the communication area of the intake hole and the exhaust hole to each curved hole, and the opening area depending on vehicle running conditions such as vehicle speed and throttle opening. and a valve body displacement mechanism that displaces the valve body in the axial direction so as to control the valve timing. [Operations and Effects of the Invention] The ceramic rotary valve type multi-cylinder internal combustion engine with a valve body displacement mechanism according to the present invention (according to claims 1 and 2) has the following operations and effects. (a) Since both the valve body and the cylinder head body are made of ceramic, the sealing performance of the sliding surfaces can be prevented from deteriorating due to differences in thermal expansion, resulting in excellent durability. (b) Since both sliding surfaces are ceramic surfaces, wear on one side can be prevented. In other words, if one of the straight hole in the cylinder head with the intake and exhaust holes and the valve body fitted into this straight hole are made of metal and the other is made of ceramic, the friction between the metal materials will be large and the durability will deteriorate. In contrast, in the present invention, since both parts are made of ceramic material, it has excellent wear resistance and can eliminate this problem.Therefore, there is no leakage at intake pressure or explosion pressure, and stable combustion of the engine is achieved. It is extremely effective in terms of airtightness. (c) Since the valve body only performs smooth rotational motion, impact force is less likely to be applied compared to a valve mechanism that performs reciprocating motion. The cylinder head and valve body have shapes that prevent stress concentration, resulting in the following effects. (d) When fired with ceramic material, manufacturing is easy and stress concentration can be prevented when thermal shock is applied. The following effects are produced by curving the intake and exhaust holes in the valve body. (E) The intake manifold and exhaust manifold can be placed on the side of the engine, reducing the vertical dimension of the engine, making it easy to mount on vehicles, small ships, etc., and the structure is simple and can be easily made of ceramic. A valve body displacement mechanism that displaces the valve body in the axial direction so as to control the communication area of the intake hole and exhaust hole to each curved hole and the valve opening timing according to vehicle running conditions such as vehicle speed and throttle opening degree. The following effects occur. (F) The ideal valve opening/closing timing and valve opening time can be adjusted according to the vehicle running conditions, thereby making it possible to increase output horsepower and output torque over the entire engine speed range, and to improve combustion savings. A ceramic cylinder head body in which one straight hole or a first and second straight hole is formed, and a cylinder head that is rotatable and slidable in the axial direction through the one straight hole or the first and second straight holes. By having a ceramic rotary valve body that fits into the valve body, the following effects are produced. (g) The communication area and valve opening timing between the straight hole and the curved holes for intake and exhaust can be controlled in a smooth manner. [Example] Next, the present invention will be described based on an example (corresponding to claim 1) shown in FIGS. 1 and 2. Figure 1 shows a 4-stroke, 4-cylinder engine.
1 to S4 are each cylinder, CS is the crankshaft, P
1 to P4 are pistons, and C1 to C4 are connecting rods. 1 is an engine cylinder head formed of a ceramic sintered body mainly made of silicon nitride ceramic having excellent thermal shock resistance such as silicon nitride; 21, 23, 2;
Reference numerals 5 and 27 indicate intake ports for each of the cylinders S1 to S4 provided in the cylinder head 1. 2 is an intake hole 21 in the cylinder head 1 parallel to the crankshaft CS;
23, 25, 27 and exhaust holes 22, 24, 2
6 and 28 are shown to intersect and communicate with each other. 3 is a cylindrical column made of ceramic sintered body mainly made of silicon nitride and fitted into the straight hole 2 so as to tightly fit with the inner circumferential wall of the straight hole 2 and to allow smooth rotation and axial sliding. This is the valve body. In this embodiment, each cylinder S1, S2, S3, S4 and each intake hole 21, 23, 25, 2 of the cylinder head.
7 and each exhaust hole 22, 24, 26, 28 are intake and exhaust holes 4 formed between the straight hole 2 and each cylinder.
1, 42, 43, and 44. The connecting surface between these air intake and exhaust holes 41, 42, 43, 44 and the straight hole 2 has an oval (ovoid) shape with a radius that gradually changes along the central axis, as shown in FIG. The axis is inclined with respect to the central axis of the straight hole 2, and each intake hole 21, 23, 25, 27 and each exhaust hole 2
The connecting surfaces of the holes 2, 24, 26, and 28 with the straight hole 2 are ellipses with the same radius. The valve body 3 has substantially perfect circular intake/exhaust holes 31, 33, which connect each intake port and each exhaust port of the cylinder head with each combustion chamber within a predetermined rotational angle range, respectively.
35 and 37 are provided. A timing gear 4 rotatably supported by the cylinder head is spline-fitted to one end of the valve body 3, and the timing gear 4 is a drive gear fixed to one end of the crankshaft CS via a timing belt 4A. 4B, and the other end is connected to a drive mechanism 8 that displaces the valve body 3 in the axial direction.
In this way, the holes 41, 42, 43, 44 for intake and exhaust
Since the shape of the connecting surface between the connecting surface and the straight hole 2 is inclined with respect to the central axis of the connecting surface, the opening timing of the valve can be adjusted, and the opening time of the valve can be adjusted by changing the radius along the central axis. increases or decreases. The drive mechanism 8 for the valve body 3 receives vehicle running conditions such as vehicle speed, throttle opening, and output shaft torque as input, and drives the valve body 3 in the axial direction via a connecting member rotatably supported by the valve body 3. It is composed of a hydraulic servo that displaces the valve body 3, a cam that comes into contact with the connecting member, rotates according to vehicle running conditions, and displaces the valve body 3, and the like. In this engine, ignition is performed in the order of S1 → S3 → S4 → S2, and the crank angle and intake, compression, explosion, and exhaust processes are performed as shown in the table.

[Table] The drive mechanism 8 for the valve body 3 displaces the valve body 3 according to the engine rotation speed, and when the rotation speed is large, the intake and exhaust holes 31, 32,
33 and 34 are intake and exhaust holes 41 and 4 of the cylinder head.
2, 43, and 44 are connected to the side that has a larger diameter and is inclined toward the faster ignition timing, and when the rotation speed is low, it is communicated to the side that is smaller in diameter and inclined toward the later ignition timing as shown in Fig. 4. let Thereby, the communication area between the intake curved hole and the intake curved hole and the valve opening timing of the valve body 3 are controlled according to vehicle running conditions such as vehicle speed and throttle opening. 5 and 6 show another embodiment (corresponding to claim 1). The engine of this embodiment has intake holes 21, 23, 25,
27 and exhaust holes 22, 24, 26, and 28 are provided on the same side of the cylinder head 1. The valve body 5 fitted so as to be slidable in the direction has an intake hole 5 that communicates with the intake holes 21, 23, 25, 27 or the exhaust holes 22, 24, 26, 28 at a predetermined rotation angle.
1, 53, 55, 57 and exhaust holes 52, 54,
56 and 58 are provided. Also in this embodiment, as shown in FIG. 6, connecting surfaces 21a, 23a, 25a, 27 are formed between the straight hole 2 and each cylinder S1 to S4 and connect with the intake hole and the exhaust hole.
a, and 22a, 24a, 26a, and 28a are formed in an elliptical shape with a radius that gradually changes along the central axis,
Furthermore, the connection surface 2 with the straight hole 2 of the intake holes 21, 23, 25, 27 and the exhaust holes 22, 24, 26, 28
1b, 23b, 25b, 27b, and 22b,
24b, 26b, and 28b are formed into oval shapes having the same radius along the central axis. 7 and 8 show still another embodiment (corresponding to claim 2). In this embodiment, the cylinder head 1 is provided with two straight holes 6 and 7 on the intake side and the exhaust side, and the intake side valve body 60 and the exhaust side valve body 70 are rotatably and slidably slidable in the axial direction into the respective straight holes. It is movably fitted to form a rotary valve. connection surfaces 21c, 23c, 25c, 27c of the intake and exhaust holes that communicate the respective straight holes and the combustion chamber;
8, 22c, 24c, 26c, and 28c are formed in an elliptical shape with a radius that gradually changes along the central axis, and the straight holes 6 and 7 and the intake holes 21, 23, 25, and 27. Exhaust holes 22, 24, 2
The connecting surfaces with 6 and 28 are formed in an elliptical shape with the same radius along the central axis. In this ceramic rotary valve type multi-cylinder internal combustion engine with a valve body displacement mechanism, the drive mechanism 80 can independently displace the intake side valve body 60 and the exhaust side valve body 70 in the axial direction, thereby opening the intake valve and the exhaust valve. The period and opening hours can be set freely, which is more advantageous in improving the output of the engine. Note that the position where the intake hole, exhaust hole, or connecting surface between the intake and exhaust hole and the straight hole provided in the cylinder head is formed into an oval shape with a radius that gradually changes along the central axis is located at a location other than the cylinder side, as shown in Figures 2 and 6. As shown by the two-dot chain line in FIG. 8, it may be on the intake pipe or exhaust pipe side, or furthermore, it may be on the intake hole, exhaust hole, or intake/exhaust hole side of the valve body.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a ceramic rotary valve type multi-cylinder internal combustion engine with a valve body displacement mechanism according to an embodiment of the present invention, FIG. 2 is a partially enlarged perspective view of a cylinder head, and FIGS. 3 and 4. is an explanatory diagram of the relationship between the displacement of the valve body in the axial direction and the opening timing and time of the valve, and FIG. 5 is a schematic perspective view of another embodiment.
FIG. 6 is a partially enlarged sectional perspective view of the cylinder head, FIG. 7 is a schematic perspective view of still another embodiment, and FIG. 8 is a partially enlarged sectional perspective view of the cylinder head. In the figure, 1... Cylinder head, 2, 6, 7... Straight hole, 3, 5, 60, 70... Cylindrical silicon nitride ceramic rotary valve disc, 8, 80... Valve disc drive mechanism, 21, 23 , 25, 27...Intake hole, 2
2, 24, 26, 28...exhaust hole, 31, 33, 3
5, 37... Intake and exhaust holes, 41, 42, 43... Intake and exhaust holes, 51, 53, 55, 57... Intake holes, 5
2, 54, 56, 58...Exhaust hole.

Claims (1)

[Claims] 1 (a) An intake hole and an exhaust hole are formed in the side wall,
One straight hole is formed that communicates with all of the intake hole, exhaust hole, and combustion chamber in the longitudinal direction and has a circular cross section, and the connection surface between the straight hole and the intake and exhaust hole is aligned along the central axis of the straight hole. (b) A ceramic cylinder head body formed into an elliptical shape with a radius that gradually changes; The curved hole for intake connects the combustion chamber and the intake hole within a predetermined crank rotation angle range, and the exhaust curved hole connects the exhaust hole and the combustion chamber within another predetermined rotation angle range. (c) A ceramic rotary valve disc that controls the communication area of the intake and exhaust holes to each curved hole and the valve opening timing according to vehicle running conditions such as vehicle speed and throttle opening. A ceramic rotary valve type multi-cylinder internal combustion engine with a valve body displacement mechanism that displaces the valve body in the axial direction. 2 (a1) An intake hole and an exhaust hole formed in the side wall, a first straight hole formed in the longitudinal direction that communicates the intake hole and the combustion chamber, and has a circular cross section; A second straight hole having a circular cross section communicating with the exhaust hole and the combustion chamber is formed, and the connecting surface between the first and second straight holes and the intake/exhaust hole is the center of the first and second straight hole. (b1) A ceramic cylinder head body formed in an elliptical shape with a radius that gradually changes along the axis; The curved hole for intake communicates with the combustion chamber and the intake hole within a predetermined crank rotation angle range, and the curved exhaust hole communicates with the exhaust hole within another predetermined rotation angle range. (c) A ceramic rotary valve body that communicates with the combustion chamber; (c) The communication area of the intake hole and the exhaust hole to each curved hole, and the valve opening timing are determined according to vehicle running conditions such as vehicle speed and throttle opening. A ceramic rotary valve type multi-cylinder internal combustion engine with a valve body displacement mechanism that displaces the valve body in the axial direction in a controlled manner.