JPS63105229A - Four-cycle spark ignition type four-valve engine - Google Patents

Abstract

PURPOSE:To aim at improvement in the combustion efficiency by providing an intake port and an exhaust port by twos respectively, and then placing those alternately in the circumferential direction. CONSTITUTION:On the upper part of a combustion chamber 3 are provided an intake port 4 and an exhaust port 7 by twos respectively. The intake ports 4 and the exhaust ports 7 are placed alternately in the circumferential direction. One of the intake ports 4, which is at a relatively low temperature, and the other of the exhaust ports 7, which is at a high temperature, are adjacent to each other, and consequently, the area of heat exchange between the intake ports 4 and the exhaust ports 7 respectively becomes larger. Hereby, the combustion state is uniformed, and the combustion efficiency can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to a gasoline engine, etc.
This relates to a 4-cycle spark ignition 4-valve engine that uses a spark plug to emit an electric spark to ignite a mixed gas.

[Conventional technology]

Conventionally, there have been four-valve engines that have two intake ports and two exhaust ports in the upper part of the combustion chamber of the engine to reduce intake and exhaust resistance and improve combustion efficiency (for example, (Refer to Japanese Patent Publication No. 1983-50207).

[Problem that the invention seeks to solve]

However, in a conventional four-valve engine, as shown in FIG. 8, two intake ports 81 and two exhaust ports 82 are provided adjacent to each other.

For this reason, the flows of the intake air taken in from the two intake ports 81 overlap in the adjacent portion 88 where the intake ports 81 are adjacent to each other, so that they are mutually obstructed. However, this causes the output to decrease. On the other hand, in the adjacent portion 84 where the high-temperature exhaust ports 82 are adjacent to each other, the valve seat (not shown) is exposed to extremely high temperatures and is therefore severely worn.

In addition, the intake port side 86 and the exhaust port side 3 in the combustion chamber 86
7, there will be a large temperature difference, so spark plug 38
The propagation speed of combustion from For this reason, knocking occurs when the relatively low-temperature fuel on the intake port side 87 remains unburned or when the compression ratio is increased. Therefore, this also causes a decrease in output.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a four-cycle spark ignition four-valve engine that can increase engine output and reduce wear on the valve seat of the exhaust port.

[Means for solving problems]

In order to achieve the above object, the present invention arranges two intake ports and two exhaust ports alternately in the circumferential direction.

[Effect]

According to this invention, since the relatively low temperature intake port and the high temperature exhaust port are always adjacent to each other in the circumferential direction, the area for heat exchange between the intake port and the exhaust port is large. Therefore, the temperature distribution in the combustion chamber is more averaged than in the past, and the combustion state is made more even, so the difference in combustion propagation speed is reduced, and the risk of unburned remains and knocking is reduced.

Also, adjacent to the intake port is the exhaust port, which is closed when the intake port is open. Therefore, the flow of intake air from the two intake ports is less likely to be inhibited by each other, so that the output is increased.

Furthermore, since the relatively low-temperature intake port is adjacent to the high-temperature exhaust port, the temperature of the valve seat of the exhaust port is lower than that in the past, and wear of the valve seat is suppressed.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, 1 is a piston, 2 is a cylinder, 8 is a combustion chamber, 4 is an intake port, 6 is an intake valve, 6 is an intake passage, 7
8 is an exhaust port, 8 is an exhaust pulp, and 9 is an exhaust passage. The intake port 4 and the exhaust lower are each circular, and the combustion chamber 8
As shown in Fig. 2, they are arranged alternately in the circumferential direction. That is, the two intake ports 4 and the exhaust lower are each arranged symmetrically with the spark plug 10 at the center.

The intake passage 6 is provided, for example, in parallel and opposite directions when viewed from the plane so that the two swirls are generated in the direction of the arrow, that is, the swirls are generated in the same circumferential direction. ing.

The intake port 4 and exhaust lower on the left side of the figure are opened and closed by a valve mechanism 12 including a camshaft 11 on the left side of FIG. On the other hand, a valve mechanism 14 including a camshaft 13 on the right side of the figure opens and closes the intake port 4 and the exhaust lower on the right side of FIG.

In the above configuration, the comparatively low-temperature intake port 4 and the high-temperature exhaust lower are adjacent to each other at the four adjacent portions 15, so that the area where both 4 and 7 exchange heat is large. therefore,
Since the temperature distribution in the combustion chamber 8 is more averaged than before, combustion efficiency is improved due to uniform combustion, and there is less risk of knocking even when the compression ratio is increased.

By the way, the hot exhaust lower is cooled, for example, by cooling water, either directly or through the intake port 4. here,
In this invention, since the heat exchange area is large, the heat of the exhaust lower easily escapes to the cooling water through the intake port 4. Therefore, since the average temperature of the combustion chamber 8 becomes lower, the intake air weight increases. In other words, filling efficiency is improved.

Furthermore, since the relatively low-temperature intake port 4 is adjacent to the high-temperature exhaust lower, the temperature of the valve seat 8a of the exhaust lower in FIG. Decline.

In addition, the intake ports 4 in FIG. 2 are adjacent to each other.
is the exhaust lower that is closed when it is open. For this reason, the distance between the two intake ports 4 is larger than before, so there is no risk of the intake air flows overlapping.
There is no risk of interference with each other. Therefore, the intake resistance becomes smaller.

Furthermore, when swirl is generated in the same circumferential direction as in this embodiment, since the two intake ports 4°4 are separated in the circumferential direction, a uniform swirl is generated throughout the combustion chamber 3. Occur. Therefore, it is possible to increase the output in the medium and low speed range without impairing high speed performance.

By the way, the valve train mechanisms 12 and 14 in FIG.
Open and close one of the intake ports 4 and υ air lower in FIG. Here, since the intake port 4 and the exhaust lower do not open at the same time, one valve mechanism 12 or 14 (FIG. 1)
The driving torque of the camshaft 11, 13 in FIG. 1 is smaller than when opening and closing two intake ports 4 or exhaust lowers.

Therefore, the drive system (not shown) for the camshaft 11.18 can be downsized and the mechanical efficiency is improved.

〔Effect of the invention〕

As explained above, according to the present invention, by adding a simple improvement such as arranging two intake ports and two exhaust ports alternately in the circumferential direction of the combustion chamber, combustion efficiency is improved through uniform combustion. However, since it becomes possible to employ a high compression ratio, the filling efficiency of intake air is improved, and the intake resistance is reduced, it is possible to achieve a significant increase in output. In addition, the valve seat of the exhaust port is less likely to wear out.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an engine showing an example of the present invention, FIG. 2 is a schematic diagram showing a combustion chamber, and FIG. 3 is a schematic diagram of a conventional engine. 8... Combustion chamber, 4... Intake port, 7... Exhaust port, 1
2゜14...Valve mechanism. Patent applicant: Kawasaki Heavy Industries, Ltd. Agent: Patent attorney Kunihide Namba (1 other person) ・Figures 1, 2, and 3

Claims (2)

[Claims] (1) In a 4-cycle spark ignition 4-valve engine in which two intake ports and two exhaust ports are provided in the upper part of the combustion chamber of the engine, the intake ports and exhaust ports are arranged alternately in the circumferential direction. A 4-cycle spark ignition 4-valve engine. (2) The one intake port and the exhaust port are opened and closed by one valve mechanism, and the other intake port and exhaust port are opened and closed by the other valve mechanism. 4 cycle spark ignition 4 valve engine.