JPH03281909A - Head integrated block for internal combustion engine - Google Patents

Abstract

PURPOSE:To simplify adjustment of a compression ratio and make precise machining/finishing of a valve seat unnecessary by providing a machining margin for adjusting the compression ratio at the surface of a rotary valve exposed to a combustion chamber at the time of ignition. CONSTITUTION:In a cylinder head portion 7, there are provided an air suction rotary valve 3 having a vent hole 4 for sucking air and a machining margin 2 for adjusting a compression ratio, and an exhaust rotary valve 5 having another vent hole 4 for exhausting air, in such a manner as to be always exposed (i.e., to face) at a part on each circumferential surface thereof to a combustion chamber 6. The cylinder head portion 7 is formed integrally with a cylinder portion 9 provided with a cylinder 8, on the inner surface of which a piston slides, and a bulk head portion 15, thus constituting a cylinder block 1 as a mono-block. Accordingly, the machining margin 2 portion can be machined independently as a single component so that the compression ratio can be adjusted. Therefore, it is unnecessary to perform predetermined machining of the combustion chamber 6 in the lower portion of the cylinder block 1 for the adjustment of the compression ratio.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to an internal combustion engine that integrally comprises a cylinder head and a cylinder block provided with rotary I-lubes for intake and exhaust. It is.

(Prior art) As a conventional head/block integrated internal combustion engine in which a cylinder head and a cylinder block are cast as one body,
For example, there is one shown in FIG. In this example,
The piston liner wall (cylinder head) 62 on which the piston 61 slides is divided into an upper liner part 63 and a lower liner part 64 in the middle of the cylinder, and the joint ends of both litchi parts are fitted into a spigot shape 65. In addition, the surface pressure at the time of fastening is set to be higher on the inner circumferential surface of the bore than on the outer circumferential side of the bore of the piston liner wall. In addition, in the figure, 66 is a combustion chamber (
(Refer to Public Utility Model Publication 1986-38459).

Furthermore, in the example shown in FIG. 7, an internal combustion engine is an integrated head/block type in which a cylinder part 72 on which a piston 71 slides and a head part 73 in which intake and exhaust valves are provided are integrally formed. The joint portion 74 is provided in the crankcase portion 76, and the opening portions of the intake and exhaust valve seats in the head portion are positioned below the piston oil ring at the piston bottom dead center to avoid interference with processing tools. It has a structure in which a notch 75 is formed. Note that 77 is a piston liner wall (see Public Utility Model Publication No. 62-69046).

(Issue 1i to be solved by the invention) However, in such a conventional head/block integrated internal combustion engine, it is difficult to process the compression ratio of the cylinder head and to close the valve seat parts of the intake and exhaust valves. Because processing is performed from the bottom of the cylinder block, the bottom part of the cylinder block is divided into parts, so there is a difference in level at the mating part, cooling water, etc.
This causes problems in processing methods such as engine oil sealing, and if the method of dividing the piston liner at the wall is discontinued and the tool is inserted from the bottom of the cylinder bore to machine the cylinder head and valve seat, the processing tool will be removed. An unstable cantilevered state or vibration may occur, making it impossible to improve machining accuracy.Furthermore, if the relative positions of the intake and exhaust valves change and the angle widens, machining of the valve seat becomes impossible. There was a problem. The present invention aims to solve the above-mentioned problems by providing a head-integrated stop block that allows adjustment of the compression ratio without using a splitting method or reducing processing accuracy. .

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention includes a cylinder provided with an intake rotary valve and an exhaust rotary valve, and a cylinder block on which a piston slides. In an integrated head/block internal combustion engine,
At least one of the rotary valves has a mechanism in which a machining allowance (machined part) for adjusting the compression ratio is provided on the surface of the rotary valve that is exposed in the combustion chamber at the time of ignition.

(Function) By using a rotary valve, the machining allowance provided in advance at a predetermined position of the valve can be machined by itself, thereby making it possible to adjust the compression ratio. Therefore, there is no need to carry out predetermined machining of the combustion chamber for compression ratio adjustment from the lower part of the cylinder block, there is no need to divide the block, and machining accuracy is improved.

(Example) Hereinafter, an example of the present invention will be described based on the drawings of FIGS. 1 to 5.

FIGS. 1 to 5 are diagrams showing an embodiment of the present invention,
It is a 4-cylinder engine. First, to explain the configuration, there is a ventilation hole 4 for intake air, a rotary valve 3 for intake having a machining allowance for compression ratio adjustment (a shallow dish-shaped recess gB corner part for adjusting the compression ratio) 2, and a ventilation hole 4 for exhaust air. A part of the circumferential surface of each of the exhaust rotary valves 5 having a rotary exhaust valve 5 is positioned in the cylinder head part 7 so that a part of the circumferential surface thereof is always exposed to (contacts) the combustion chamber 6. This cylinder head part 7 is formed integrally with a cylinder part 9 and a bulkhead part 15, which are provided with a cylinder 8 on which a piston (along with other parts such as a spark plug, is omitted to simplify the drawing description) slides on the inner surface. The cylinder block l is a monoblock.

The bulkhead portion 15 of the cylinder block 1 has a cap 1
1 integrally with the bearing lower cap 1.
2 are fastened with cap bolts 13 to support the main journal 14 of the crankshaft. Cylinder block≠
A notch for boring the cylinder 8 is provided in the bulkhead portion 15 of the cylinder 1 . Moreover, an example of the structure of the intake rotary valve 3 is shown in FIG. 2(a). This intake rotary valve 3 is provided with a vent hole 4 that is bored according to the number of four cylinders of the internal combustion engine, and a machining allowance 2 for compression ratio adjustment is provided at a predetermined position in relation to the vent hole 4. ing. Furthermore, FIG. 2(b) is a sectional view taken along the line AA' of the vent hole 4 of the intake rotary valve 3 shown in FIG. 2(a), and shows the compression ratio with respect to the center 0 of the vent hole 4. The adjustment machining allowance 2.2 is provided at a symmetrical position. As will be described later, the machining allowances 2 are provided in such a manner that they alternately occupy positions exposed within the combustion chamber 6 during ignition and combustion.

Next, the operation of the above embodiment will be explained.

FIG. 3 shows an example of the operation of the intake rotary valve 3. Here, the rotation speed of the intake rotary valve 3 is 1/4 of the rotation speed of the internal combustion engine, and the rotation direction of the rotary valve is 2.
0 is clockwise (rotation direction of the clock hands). The positional relationship between the vent hole 4 and the opening position 17 on the combustion chamber side is such that when the rotary valve rotates, the vent hole 4 opens as shown in FIG.
begins to open, passes through the intake period (period) 16, and reaches the closing timing shown in FIG.

In addition, in the figure, TDC is located at every 90° at the top dead center position. The fuel mixture taken in during the intake period 16 is sealed in the combustion chamber 6 by the rotation of the intake rotary valve 4, and is compressed by the movement of the piston. After that, the intake rotary valve 3 rotates further, and the third hardening) ignition timing 18
At the point when the fuel-air mixture reaches this point, it ignites and burns explosively.

At this time, the machining allowance 2 on the surface of the intake rotary valve 3 exposed to the combustion chamber 6 occupies position 19 in FIG. 3(C).

Since the two machining allowances 2 are provided symmetrically, the other machining allowance 2 will be exposed to the combustion chamber 6 at the next ignition timing, and will thus be exposed to the combustion chamber 6 alternately.

The machining allowance 2 for adjusting the compression ratio is easily machined by the valve 3 alone in order to form a shallow dish-like concave shape so as to obtain a predetermined compression ratio in relation to the volume of the combustion chamber 6. In that case, it is desirable to process the shape so that it connects smoothly with the shape of the combustion chamber 6. Further, the machining allowance 2 for adjusting the compression ratio may be provided on the intake rotary valve 3 as in this embodiment, but it may also be provided on either one or both of the exhaust rotary valves 5. The rotary valve 3 and the exhaust rotary valve 5 must be provided on a surface exposed to the combustion chamber 6 when the ignition timing is reached. Note that, after the combustion stroke, the exhaust rotary valve 5 similarly rotates 111 to discharge the exhaust gas from the combustion chamber 6, and then returns to the original intake stroke, as in the normal case.

FIGS. 4 and 5 show other embodiments.

This embodiment has a structure in which both the intake rotary valve 3 and the exhaust rotary valve 5 are provided with a compression ratio adjustment machining allowance 2 in the shape of a narrow recess in the circumferential direction of the rotary valve at a predetermined position. It is made up of things. In FIG. 4, the rotation speed of the intake rotary valve 3 and the exhaust rotary valve 5 is 1/1/1 of the rotation speed of the internal combustion engine, as in the previous embodiment.
4, the rotation direction 2o of the rotary valve is clockwise, and this figure shows the positions of the intake rotary valve 3 and the exhaust rotary valve 5 when the ignition timing has just been reached at the end of the compression stroke. . The machining allowance 2 for compression ratio adjustment is machined into a narrow shape relative to the circumferential distance of the rotary valve.
Areas where knocking may occur after ignition, i.e.
If the valves 3 and 5 rotate in the state shown in this figure, they will come out of the combustion chamber 6. In this way, the machining allowance 2 has deviated from the combustion chamber 6 in rotation by the time the expansion stroke starts, so the cylinder internal pressure during the expansion stroke will change as shown in Fig. 5 due to the volume reduction of the recess. The pressure is higher than the conventional pressure line shown by the solid line in the P-v diagram, and the pressure line shown by the dotted line is obtained.As a result, the (shaded area) of the internal combustion engine
output is improved.

Furthermore, by providing this machining allowance 2 for compression ratio adjustment on both the intake rotary valve 3 and the exhaust rotary valve 5, and by making the depth of the compression ratio adjustment machining allowance 2 shallow, combustion It also improves efficiency.

[Effects of the Invention] As described above, according to the present invention, the head/block unit is constructed by integrally comprising a cylinder head provided with intake and exhaust rotary valves and a cylinder block on which a piston slides. In an internal combustion engine, at least one of the rotary valves has a structure in which a machining allowance for compression ratio adjustment is provided on the surface of the rotary valve that is exposed in the combustion chamber at the time of ignition, making it easy to adjust the compression ratio. At the same time, there is an effect that precision processing and finishing of the valve seat, which conventionally required precision processing and finishing, becomes unnecessary.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an example of an integrated head/block internal combustion engine according to the present invention, FIG. 2 is a perspective view for explaining an example of an intake rotary valve according to the present invention, and FIG.
is a sectional view taken along the line A-A' of the second image), FIG. 3 is an action explanatory diagram using a sectional view of the intake rotary valve, and the fourth factor is
A sectional view of another embodiment of the present invention in which intake and exhaust rotary valves are provided with machining allowance for compression ratio adjustment, FIG. 5 is a p-v diagram for explaining the effect of the one in FIG. 4, FIGS. 6 and 7 are cross-sectional views of an example of a conventional head/block integrated internal combustion engine. 1...Cylinder block, 2...Machining allowance for compression ratio adjustment, 3...Rotary valve for intake, 4...Vent hole,
5... Rotary valve for exhaust, 6... Combustion chamber, 7.
・Cylinder head part, 8...Cylinder, 9...Cylinder part, 10...Connecting rod, 11...Bearing・
Upper cap, 12... Bearing lower cap, 13... Cap bolt, 14... Main journal, 15... Bulkhead section, 16... Intake timing, 17... Combustion chamber side opening position , 18...Ignition timing,
19...Compression ratio adjustment position, 20...Rotary valve rotation direction.

Claims (1)

[Claims] In a head/block integrated internal combustion engine that is configured integrally with a cylinder provided with an intake rotary valve and an exhaust rotary valve, and a cylinder block on which a piston slides, at least one of the rotary valves is used for ignition. An integrated head block for an internal combustion engine, characterized in that a machining allowance for compression ratio adjustment is provided on the surface of a rotary valve that is sometimes exposed inside a combustion chamber.