JPH02275011A - Cooling system for internal combustion engine - Google Patents

Abstract

PURPOSE:To accelerate the extent of fuel carburetion by installing a means which selects a flow of cooling water to an exhaust port side cooling water duct at time of partial load driving and to an intake port side cooling water duct at time of the high load driving, respectively, out of two cooling water ducts leading to each cooling water passage at both these intake and exhaust port sides. CONSTITUTION:In a cylinder head 2 provided with each two of intake and exhaust ports 3, 7 at each combustion chamber, cooling water passages 5, 8 extending in the cylinder array direction are installed in each underside of these intake and exhaust ports 3, 7. In addition, there is provided a combustion chamber upper side cooling water passage 6 which traverses the upper part of the combustion chamber between these intake and exhaust ports 3, 7, surrounding a spark plug hole, and extending in the cylinder array direction, and a partition wall 26 with a partial connecting passage 25 is installed in this passage 6. These passages 5, 8 are connected to a cooling water passage at the discharge side of a pump 1 via cooling water ducts 27, 28 and a passage selector valve 34, and this passage selector valve 34 is selected so as to lead a flow of cooling water the exhaust port side cooling water duct 28 at time of partial load driving but to the intake port side cooling water duct 27 at time of the high load driving, respectively.

Description

[Detailed description of the invention] Application field of industry-1- The present invention relates to a cooling device for an internal combustion engine.

BACKGROUND OF THE INVENTION Conventional cooling systems for internal combustion engines include those shown in FIGS. 3 and 4, for example.
6126, JP-A-62-107220, etc.).

That is, in the conventional example shown in FIG. 3, the cooling water is
It is pressurized by the cooling water pump l and flows into the cylinder head 2 from the cooling water population 4 located below the intake port 3 of the cylinder head 2, passes through the intake port side cooling water passage 5, and the combustion chamber upper cooling water passage 6. , flows toward the exhaust port 7 side, and flows from the exhaust port side cooling water passageway 8 to the cooling water passageway in the cylinder block 9 l.

cooling the cylinder block 9.1. Outflow 17 from the cylinder block side cooling water outlet 11, radiator I2
The internal combustion engine is cooled by repeating a cycle in which the temperature of the cooling water is lowered through the cooling water pump 1, the cooling water is pressurized again by the cooling water pump 1, and the cooling water flows into the cylinder head through the cooling water pump 4.

Furthermore, a cooling system for an internal combustion engine as shown in FIG. 4 has been known (see Japanese Patent Laid-Open No. 62-107220), in which the lower part of the intake port 3 is cut (M) in the cylinder arrangement direction. The intake port-1 lower cooling water passage 13 extends 4 inches, the exhaust port lower cooling water passage 14 extends in the cylinder arrangement direction across the lower side of the exhaust port 7, and the intake port 3 side and the exhaust A combustion chamber upper cooling water passage 16 extending in the cylinder arrangement direction between the upper part of the combustion chamber and the port 7 side is divided into sections 12 and independent from each other, and the cooling water passage is provided in the cylinder head 2. Valve chambers 19 and 20 are provided at both ends of the head 2 and extend in the direction in which the three cooling water passages 13, 14j 6 are arranged, that is, in a direction perpendicular to the direction in which the cylinders are arranged. 20 are provided with cooling water flow path switching valves 21 and 22, respectively.

The cooling water flow path changes depending on the load or rotation speed of the internal combustion engine.
The order in which the cooling water flows through the intake port lower cooling water passage 13 and the exhaust port lower cooling water passage 14 is selectively changed. At partial load and at idle, cooling water flows through the intake port lower cooling water passage 1 due to the mechanical octane rating.
3 to the exhaust port lower cooling water passage 14, whereas during high load operation, cooling water flows from the exhaust port lower cooling water passage 14 to the intake port lower cooling water in order to lower the exhaust gas temperature during high load operation. The flow path is switched so that it flows to the path 13. In addition, J-17 is designed to improve the mechanical octane number during partial load and idle, and reduce the exhaust gas temperature during high load operation.

Problems to be Solved by the Invention However, in these conventional cooling systems for internal combustion engines, the intake port side region is cooled before the exhaust port side region during partial load and idling.
The area on the intake port side is cooled more strongly than other parts by the low-temperature cooling water, 1- Good, the vaporization of the fuel in the intake air-fuel mixture is worsened. 2. The amount of fuel adhering to the intake port wall increases. (2), the air-fuel mixture becomes lean and combustion worsens,
Fuel efficiency also worsens. Furthermore, in the conventional example shown in FIG. 4, during high-load operation, cooling water is flowed from the exhaust port side region to the intake port side region for cooling. However, when the internal combustion engine is operating under high load, the temperature inside the combustion chamber on the exhaust port side is higher than on the intake port side, so the flame propagation of the air-fuel mixture in the combustion chamber is less on the intake port side than on the exhaust port side. 17 The unburned part of the air-fuel mixture near the intake port self-ignites, causing a local temperature rise on the combustion chamber wall.
The possibility of knocking occurring is greatest. For this reason, it is not possible to prevent the occurrence of IJ knocking during high-load operation.

As mentioned above, conventional cooling systems for internal combustion engines have the problem of not being able to prevent the deterioration of vaporization of the fuel mixture during partial load operation and idling, and the occurrence of knocking during high load operation. There was a point.

The present invention focuses on such conventional problems as follows: 1. When the internal combustion engine is operating at partial load or idling, cooling water flows from the exhaust port side area to the intake port side area, and during high load operation, cooling water flows from the intake port side area to the exhaust port side area. The purpose is to solve the above problems by allowing water to flow.

Means for Solving the Problems Therefore, the present invention provides a cooling water passage on the intake port side, a cooling water passage on the exhaust port side, and an upper side of the combustion chamber, which communicate with each other in the cylinder head of an internal combustion engine and extend in the cylinder arrangement direction. In a cooling device for an internal combustion engine having a cooling water passage, a partition wall provided in the cooling water passage on the second side of the combustion chamber and restricting the flow of cooling water between the intake port side and the exhaust port side; A cooling water conduit connected to the cooling water passage and the exhaust port side cooling water passage, respectively, and a cooling water conduit of these two cooling water conduits connected to the exhaust port side cooling water passage when the internal combustion engine is operating at partial load or idle. Furthermore, a cooling water passage switching means is provided for switching the flow of cooling water to a cooling water conduit connected to the intake port side cooling water passage during high load operation.

When the operating engine is in a partial load state or in an idling state, the cooling water passage switching valve allows cooling water to flow into the exhaust port side cooling water conduit, cooling the exhaust port 1-1 before the intake port. The cooling water that cooled the exhaust port side is
It flows through the interconnection passage to the intake port side and cools the intake port side.

On the other hand, when the engine load is high, the cooling water flow path switching valve flows the cooling water to the intake port side cooling water conduit l11.
, cool the intake port side first. The cooling water that has cooled the intake port side flows to the exhaust port side through a partial communication path between the partition walls, and cools the exhaust port side.

EXAMPLES Hereinafter, the present invention will be explained based on the drawings. FIG. 1 and FIG. 2 are diagrams showing one embodiment of the present invention.

Fig. 1 shows an overview of the overall configuration, and Fig. 2 is a perspective view showing the main parts. Note that the arrows in FIG. 2 indicate the flow of cooling water.

First, the configuration will be explained. The same components as the conventional example include:
The same reference numerals are given]7, and the explanation will be omitted.

The cylinder head 2 has two intake ports 3 for each combustion chamber.
and two exhaust ports 7 are provided.

Below the intake port 3, there is an intake port side cooling water passage 5 extending in the cylinder arrangement direction, and below the exhaust port 7 there is an exhaust port side cooling water passage 8 extending in the cylinder arrangement direction. A combustion chamber between the port 3 side and the exhaust port 7 side (a combustion chamber extending in the cylinder arrangement direction surrounding the spark plug hole 15 across three sides) is in communication with the second side cooling water passage 6, respectively.
It is installed 3 times. The upper cooling water passage 6 of the combustion chamber has a connecting passage 25 in order to restrict the flow of cooling water from the intake port side cooling water passage 3 side to the exhaust port side cooling water passage 8 side or the opposite direction. A partition wall 2G is provided.

Here, the partition wall 2G takes into consideration the pressure gradient of the cooling water flow.
- In order to keep the amount of cooling water flowing to each cylinder through the interconnection passage 25 etc. constant, the cooling water volume is gradually decreased from the cooling water population 27° 28 toward the exit 29.

Further, at one end of the cylinder head 2 in the cylinder arrangement direction, an intake port side cooling water conduit 27 and an exhaust port side cooling water conduit 2 are provided.
8, and one cooling water outlet 29 is provided at the other end of the cylinder head 2. A cylinder block side cooling water inlet 30 is provided below the side end surface of the cylinder block 9 on the cooling water outlet 29 side. Further, on the upper surface of the other end of the cylinder block 9, there is a cooling 1. A communication hole 3 is provided through which cooling water flows into the cylinder head 2 side.

The cooling water passage flowing into the cylinder head 2 is connected to a cooling water flow path switching valve 34 in front of the cooling water inlet of the cylinder head 2.
It is divided into two via 11, and communicates with the intake port side cooling water population 27 and the exhaust port side cooling water population 28, respectively.

In addition, 32 is a temperature-sensitive valve that also functions as a flow path switching valve, which allows the cooling water to pass through the bypass passage 33 instead of the radiator 12 when the temperature of the cooling water is low; 31 is a temperature-sensitive valve that connects the cylinder block 9 and the cylinder head 2; It is a communicating hole.

Next, the action will be explained.

When the internal combustion engine is in a partial load state or in an idling state, the cooling water flow switching valve 34 causes cooling water to flow into the exhaust port side cooling water conduit 28, cooling the exhaust port 7 before the intake port 3, and cooling the exhaust port 7 side. The cooling water cools the intake port 3 side through a partial communication passage 27 in the cylinder head 2.

Furthermore, when the internal combustion engine is operating under a high load, the cooling water flow switching valve 34 causes the cooling water to flow into the intake port side cooling water conduit 27 to cool the intake port 3 first, and then to pass through the intercity passage 25. to cool the exhaust port 7.

The cooling water flow path switching valve 34 is operated as shown in FIG. It operates under the control of a separate control unit and switches the flow path.

When the internal combustion engine is in a partial load state or in an idling state, the cooling water is warmed by cooling the exhaust port 7 first, and this high-temperature cooling water flows to the intake port 3 side, so that the wall temperature of the intake port 3 decreases. This increases the vaporization of the fuel mixture and suppresses fuel adhesion to the intake port wall.

This provides good combustion conditions and improves fuel efficiency.

When the internal combustion engine is in a high Q load state, Δ is higher than the temperature in the combustion chamber on the exhaust port 7 side than on the intake port 1-3 side, so the air-fuel mixture in the combustion chamber is higher than that on the Flame propagation on the port 3 side becomes slower.

As a result, the unburned portion of the air-fuel mixture near the intake bow 1-3, where the combustion speed is slow, self-ignites.1. This causes the local temperature of the combustion chamber wall to rise, making knob king more likely to occur. Therefore,
If the intake port 3 side is sufficiently cooled with low-temperature cooling water first, the wall temperature of the intake port 3 will decrease, which will suppress the self-ignition of the unburned portion of the air-fuel mixture in the combustion chamber and suppress the occurrence of knocking. Engine output can be improved.

The partition wall 2G provided in the second side cooling water passage 6 of the combustion chamber restricts the mixed flow of cooling water between the intake port side cooling water passage 5 side and the exhaust port side cooling water passage 8 side, so cooling The effects of this will be further improved.

As described in detail, according to the internal combustion engine cooling device of the present invention, the exhaust port is first cooled during partial load or idling, and the coolant thus warmed can warm the intake port. , fuel vaporization is promoted, fuel adhesion to the intake port side is reduced, the air-fuel ratio of the air-fuel mixture in the combustion chamber is achieved as per the target, and combustion is improved.
Fuel efficiency improves.

During high-load operation, cooling the intake port side first with low-temperature cooling water prevents a local temperature rise on the combustion chamber wall near the intake port, suppressing the occurrence of knocking and reducing the internal combustion engine. 1'
can be done.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram showing an overview of an embodiment of the present invention, Fig. 2 is a perspective view showing the main parts of Fig. 1, Fig. 3 is a sectional view showing a conventional example, and Fig. 4 is a diagram showing another example. FIG. 2 is a plan view showing a conventional example. 2... Cylinder head, 3... Intake port, 5...
・Intake port side cooling water passage, 6...Combustion chamber'' second side cooling water passage, 7...Exhaust port, 8...Exhaust port side cooling water passage, 25...-Tokyo connection passage, 26.・・Bulkhead, 2
7...Intake port side cooling water conduit, 28...Exhaust port cooling water conduit, 29...Cooling water outlet.

Claims (1)

[Claims] (1) A cooling system for an internal combustion engine that includes an intake port side cooling water passage, an exhaust port side cooling water passage, and a combustion chamber upper cooling water passage that communicate with each other and extend in the cylinder arrangement direction in the cylinder head of the internal combustion engine. , a cooling water conduit connected to the intake port side cooling water passage and an exhaust port side cooling water passage, respectively, and one of these two cooling water conduits connected to the exhaust port side cooling water passage when the internal combustion engine is operating at partial load or when idling. A cooling device for an internal combustion engine, characterized in that a cooling water flow switching means is provided for switching the flow of cooling water to a cooling water pipe connected to a cooling water pipe connected to an intake port side cooling water passage during high-load operation.