JPH0374507A - Valve arrangement for internal combustion engine - Google Patents

Abstract

PURPOSE:To simplify structure and reduce noise by constituting valves for opening and closing intake and exhaust ports as rotary valves attached rotatably around a shaft. CONSTITUTION:An intake passage 9 and an exhaust passage 10 are formed at each cylinder chamber 13 inside a cylinder head 7 of a multicylinder 4-cycle engine. Square groobve-shaped intake and exhaust ports 11, 12 are formed at one end side of the intake and exhaust passage 9, 10 to communicate with the cylinder chamber 13. A pair of parallel valve shafts 14a, 14b having a plural number of rotary valves 19a, 19b are supported for free rotation near the intake and exhaust ports 11, 12 and rotated via a timing belt 18 synchronously with a crankshaft 4. The rotary valves 19a, 19b are formed in a C-shape, a part of whose circumferential surface 20 opens as a valve port 21a, 21b. The opening length thereof is set nearly equal to the groove length of the intake and exhaust port 11, 12.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pulp device for intake and exhaust in internal combustion engines such as automobile engines (including diesel engines as well as gasoline engines).

(Prior Art) An example of this type of internal combustion engine is shown in FIG. FIG. 7 is an enlarged view of the vicinity of a valve in a type of engine called an OHC among four-cycle engines for automobiles. As shown in the figure, the cylinder head 50 has an intake valve 51ε for inhaling the air-fuel mixture.
, and an exhaust valve 52 for discharging exhaust gas, one for each cylinder chamber 53. As these valves 51 and 52, poppet valves have conventionally been used in most cases. This valve 51.5
Regarding the second driving method, various methods have been devised in the past. The one in FIG. 7 is an example in which the valves 51 and 52 are opened and closed by a so-called swing arm type.

Briefly, a camshaft 54 that rotates in conjunction with the crankshaft is arranged above the cylinder head 5o, and the cam 56 pushes down an arm 55 that is swingably supported, thereby opening the valve at a predetermined timing. 51.
52 is activated. -The swing arm type mentioned as an example has been often used to increase intake/exhaust efficiency because it is easy to increase the valve lift.

(Problem 8 to be solved by the invention) However, not only the above-mentioned swing arm type, but also other types of valves that operate by moving the poppet valve up and down have the following points to be improved. be.

■Driving force is transmitted to the camshaft 54 mentioned above from the crankshaft via a timing pulley, a timing belt, etc., but if the timing belt deteriorates over time and breaks, Depending on the timing of the ! ! The piston 57 collides with the valve 51 that does not move in the open state, and as a result of interference between the two, a situation arises in which the piston 57, the valves 51 and 52, or the surrounding members are damaged. In such a case, even if a damaged valve or the like is to be replaced, the cylinder head must be removed, and the repair work involves many steps and is extremely troublesome.

In order to avoid this problem, it is possible to avoid interference between the two by setting the piston's top dead center position lower or by forming a recess on the top surface of the piston head, but it is not possible to simply do this. There are problems such as the inability to set a high compression ratio.

■The mechanism for opening and closing the valve is the camshaft 54 and the cam 5.
6. There are many constituent members such as the arm 55 and the return spring 58, making the overall structure complicated.

For this reason, assembly is not easy and leads to an increase in cost.

■Since there are many components, there are many sources of noise, and the sound of the cam 56 or the vertical movement of the opening/closing system increases the noise of the valve device, which impairs the quietness of the engine. .

An object of the present invention is to provide a valve device that can solve these problems.

(Means for Solving the Problems) In order to achieve the above object, the valve device of the present invention is used in an internal combustion engine equipped with a valve that opens and closes an intake port or an exhaust port leading to a cylinder chamber at predetermined timings. We decided to use a rotary valve.

The valve is mounted outside the cylinder chamber and to the port portions so as to be rotatable around the valve shaft, and a portion of the valve is connected to the intake or exhaust port at a predetermined timing. These ports were designed with valve ports that could be opened.

(Operation) When the engine is driven and the valve rotates around the valve shaft, the valve port formed in a part of the valve communicates with the intake or exhaust port at a predetermined timing, and the air-fuel mixture is sucked or exhausted through these ports. Exhaust the exhaust gas.

(Example) Hereinafter, an example embodying the present invention will be described in detail with reference to the drawings.

The second diagram shows an outline of a four-stroke engine with four cylinders.
In the figure, 1 to 1 are pistons, which are built into each cylinder chamber 13 in the cylinder block 2 so as to be movable up and down. The connecting rod of each piston 1 is connected to a crank bin portion of a crankshaft 4, respectively. A flywheel 5 for preventing uneven rotation is fitted to the rear end of the crankshaft 4, and a crankshaft timing pulley 6 having teeth cut into its circumferential surface is fitted to the front end.

On the other hand, as shown in FIG. 1, spark plugs 8 are vertically mounted on the upper surface of a cylinder head 7 assembled to the upper surface of the cylinder block 2, corresponding to each cylinder chamber 13. Further, inside the cylinder head 7, an intake passage 9 and an exhaust passage 10 are defined for each cylinder chamber 13. As shown in FIG. 3, at one end of each intake passage 9 and exhaust passage 10, an intake port 11 and an exhaust port 12 each open in the shape of a substantially rectangular groove and communicate with each cylinder chamber 13. However, in this example, as shown in Fig. 3, the intake port 12 is formed wider for the purpose of increasing intake efficiency, and accordingly, as shown in Fig. 1, the rotary valve on the intake side is 19a is larger.

Now, the intake port 1 in the intake passage 9 and the exhaust passage 10
1. A pair of valve shafts 14a and 14b having rotary valves 19a to 19a and 19b to 19b, which will be described later, are provided in parallel near the exhaust port 12. That is, the two valve shafts 14a and 14b are provided in parallel, one for intake 14a and the other for exhaust 14b, so as to extend horizontally between the respective cylinders.

As shown in FIG. 4, both valve shafts 14a and 14b are rotatably supported within the cylinder head 7 by bearings 28 interposed between the respective cylinders. The front end sides of both valve shafts 14a, 14b each protrude from the cylinder head 7 to the outside, and timing pulleys 15a, 15b each having teeth carved on the circumferential surface are fitted to each shaft end.

A toothed timing belt 18 is passed between both timing pulleys 15a, 15b and the above-mentioned crankshaft timing pulley 6 via tension pulleys 16, 17. , 14b are driven in conjunction with the crankshaft 4. However, since this is a four-cycle engine, the number of teeth on both timing pulleys 15a and 15b is set to twice the number of teeth on the crankshaft timing pulley 6.

Further, on both the valve shafts 14a and 14b, there are rotary valves 19a to 19a for opening and closing each intake port 11 and exhaust port 12, respectively.
19b to 19b are attached respectively. Also,
Each rotary valve 19a.

19b, as shown in FIG.
It is supported by a support wall 25 formed inside, so that it can withstand impact during explosive combustion.

As shown in FIG. 3, each of the rotary valves 19a and 19b has a valve port 21a in a portion of its peripheral surface 20.

It has a C-shaped exterior with an opening as b, and its peripheral surface 2
The width of 0 is set approximately equal to the groove width of both ports 11 and 12, so that the intake port 11 and the exhaust port 12 can be sealed. In addition, the opening lengths of the valve ports 21a and 21b are set to be approximately equal to the groove lengths of the intake port 11 and exhaust port 12, and when aligned with the ports 11.12, these ports 11.12 can be fully opened. However, in the misaligned state, the ports 11.12 are connected to the peripheral surface 20.
It is sealed by fitting a part of it. Further, each of the rotary valves 19a, 19b is connected to the valve shaft 14a, 14b with the valve shaft 14a, 14b disposed approximately at the center thereof. That is, the seal surface 20 side and the shafts 14a, 14b
A connection surface 22 that connects the valve shaft 14a is formed to be slightly thinner than the seal surface 20, and a portion of the connection surface 22 near the valve port 21 is largely removed.

14b is exposed for approximately half its circumference. in this way,
By removing the thickness of the connection surface 22 to the maximum extent possible while maintaining a predetermined strength, intake/exhaust efficiency is improved.

However, the arrangement of the valve ports 21 in each rotary valve 19a, 19b depends on the ignition order of each cylinder chamber 13 and the intake/air intake.
It is determined according to the timing of exhaust. Furthermore, in this example, the rotation direction of the rotary valve 19b on the exhaust side is set clockwise in FIG. By opening from the second side, the heat of the exhaust gas can be effectively released.

Furthermore, as shown in FIG. 3, a water channel 27 communicating with the water jacket 26 is formed inside each of the above-mentioned supporting walls 25 to cool the valves 19a and 19b.

Since this embodiment has a groove bottom as described above, when the crankshaft 4 rotates, both valve shafts 14a are connected to each other via the timing belt 18.

14b rotates at a constant speed. Along with this, each rotary valve 19a, 19b rotates together, and the valve port 21 is connected to the intake or exhaust port 11.1 at a predetermined timing.
Connects with 2. Therefore, in the case of the inhalation stroke,
Since the valve port 21a of the intake side 6-crivalve 19a communicates with the intake port 11, the air-fuel mixture that has flowed into the intake passage 9 is sucked into the cylinder chamber 13 via the intake port 11. In this case, as mentioned above, the valve port 21
Since the area near a is largely removed, the air-fuel mixture flows smoothly.

Conversely, in the case of the exhaust stroke, the valve port 21b of the rotary valve 19b on the exhaust side communicates with the exhaust port 12, and exhaust gas is discharged through the reverse order of the intake stroke. Become.

The effects of this example are listed below.

■ Even if the timing belt 18 breaks due to deterioration over time, the piston 1 and valves 19a, 19
There is no interference between the parts and parts b, and damage to these parts and the surrounding parts can be avoided.

■Unlike before, the valves 19a and 19b do not move up and down, so the top dead center position of the piston can be set as high as possible, which increases the compression ratio and improves fuel efficiency. can.

■By using a rotary valve, the number of parts is reduced compared to the past, and the configuration can be simplified. Additionally, by reducing the number of parts, the weight of the engine can be reduced, and mechanical losses are also reduced, which is expected to reduce engine output loss.

(2) Furthermore, since the valves 19a and 19b are of a type that opens and closes by rotation, they are quieter than the conventional type that opens and closes by vertical movement. Furthermore, as mentioned in (2), since the valve mechanism is simple, the noise generated by the entire mechanism can be reduced.

■The conventional method involves assembling the parts that make up the valve mechanism in the height direction, which increases the overall height of the engine, but with this example, the height of the entire engine increases. Since no assembly is required, the height of the engine can be reduced, allowing the bonnet line to be lowered.

This increases the degree of freedom in design and also contributes to noise reduction by lowering the position of the noise source.

5 and 6 show a second embodiment of the present invention, and in the second embodiment, each rotary valve 23a, 23b
Valve shafts 24a and 24 (rotary valves)
By rotating the valves 23a and 23b around the valve shafts 24a and 24b, both the intake and exhaust ports 11 and 12 are opened and closed. That is, the valve shafts 24a, 24b of the respective valves 23a, 23b are arranged outside the cylinder head 7, and a portion of the valves 23a, 23b enters the cylinder head 7 with sealing performance ensured, thereby providing suction. - The exhaust passages 9 and 10 can be closed without any gaps. In addition, as shown in FIG. 5, each valve 23a, 23b is cut out over an angular range sufficient to fully open the intake/exhaust port 11.12.
, 25b, and both ports 11 at a predetermined timing.
, 12 are opened.

In the second embodiment configured in this way, the valves 23a, 2
Since a part of 3b is exposed outside the combustion chamber, there is an advantage that heat dissipation is excellent. The other configurations are the same as those of the first embodiment, and thus substantially the same effects as those of the first embodiment can be achieved.

Note that any of the embodiments can be applied to a diesel engine, and the type of valve mechanism is not limited to these. In addition, the intake
The exhaust side ports 11, 12 are not limited to a rectangular groove shape, but may be circular.

(Effect of the invention) The effects of the present invention are as follows.

Even if the timing belt breaks, interference between the valve and the piston can be avoided, and high compression is possible, so low fuel consumption can be achieved.

Furthermore, the number of members constituting the valve mechanism is small, simplifying the mechanism and reducing costs.

Furthermore, since the valve uses a rotary valve, it is quieter than before.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a state in which the valve device according to the first embodiment is installed, FIG. 2 is a perspective view schematically showing the valve drive mechanism, FIG. 3 is a perspective view of the valve, and FIG. The figure is a front sectional view schematically showing the valve part, FIG. 5 is a sectional view schematically showing the valve device according to the second embodiment, FIG. 6 is a plan sectional view of the same valve, and FIG. 7 is a conventional It is a sectional view showing a valve device. 11... Intake port 12... Exhaust port 13... Cylinder chamber 19 a, b, 23 a, b-...
Rotary valve 1...Intake port 2...Exhaust port 3...Cylinder chambers 9a, b, 23a. ...Rotary valve 19a (19b)

Claims (1)

[Scope of Claims] In an internal combustion engine equipped with a valve that opens and closes an intake port or an exhaust port communicating with a cylinder chamber at predetermined timing, each of the valves is rotatable around its valve shaft with respect to the corresponding port portion. 1. A valve device for an internal combustion engine, wherein the valve device is assembled and a part thereof is a rotary valve having a valve port that communicates with the intake or exhaust port and opens these ports at a predetermined timing.