JPH0477134B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a method for preheating intake air in a so-called slant-type internal combustion engine in which the axis of the cylinder bore is inclined (slanted) with respect to the horizontal line when viewed from the direction of the crankshaft. This invention relates to a cooling device equipped with a mechanism.

[Conventional technology and its problems]

Utility Model Publication No. 61-37818 as prior art,
In a slant-type internal combustion engine, the intake manifold connected to the longitudinal side of the cylinder head communicates with the cooling water chamber of the cylinder head at the location of each cylinder, and the cooling water from the cooling water chamber of the cylinder head to the radiator. A cooling device with an intake air preheating mechanism has been proposed in which an intake air preheating passage communicating with an outlet is provided, and a thermo valve is provided at the cooling water outlet to open when the temperature of the cooling water becomes high.

However, due to the slanted internal combustion engine, the intake preheating passage in this cooling system is located at the highest point in the cooling water circulation path, and air accumulates in this part. Nevertheless, the air accumulated in this intake preheating passage,
Since the cooling water will not leak out unless the thermo-valve is opened, it is difficult to fully inject cooling water into the cooling water circulation path, which requires a great deal of effort. The circulation of the cooling water flowing out from the cooling water chamber to the intake preheating passage and then returning to the cooling water chamber of the cylinder head is obstructed by the air accumulated in the intake air preheating passage. Sufficient intake air preheating could not be achieved.

Moreover, the cooling device with an intake air preheating mechanism of the prior art does not supply cooling water to the internal combustion engine, even though the intake air preheating passage is located at the highest point in the cooling water circulation path due to the internal combustion engine being slanted. During normal operation after the temperature has risen to a predetermined temperature, the flow of cooling water to the intake air preheating passage is stopped. High-temperature flowing cooling water accumulates due to convection. In other words, high-temperature cooling water collects in the intake preheating passage located at the highest point, so preheating of the intake air is not excessive. As a result, a problem arises in that the efficiency with which intake air is filled into the internal combustion engine is reduced.

An object of the present invention is to provide a slant type internal combustion engine cooling device that eliminates these problems.

[Means for solving problems]

For this reason, the present invention has an arrangement in which the axis of the cylinder bore when viewed from the direction of the crankshaft is inclined with respect to the horizontal line, and the intake manifold connected to the longitudinal side of the cylinder head is connected to the cooling water chamber of the cylinder head. In a slant-type internal combustion engine that is provided with an intake preheating passage that communicates with each cylinder, the intake preheating passage is connected to a cooling water outflow passage from the cooling water outlet of the cylinder head to the radiator, or to a cooling water filler provided in the radiator with a small diameter. On the other hand, the cooling water return passage from the radiator to the cooling water chamber of the cylinder block via the cooling water pump,
A thermo-valve case is provided on the suction side of the cooling water pump, and a small-diameter first bypass passage from the intake air preheating passage is connected to the thermo-valve case. When the temperature of the cooling water is low, the communication of the cooling water return passage to the cooling water pump is cut off and the first bypass passage is communicated with the cooling water pump, and when the temperature of the cooling water is high, the cooling water return passage is communicated with the cooling water pump. Additionally, a thermo valve configured to close the first bypass passage is provided, and the intake preheating passage or the air vent passage and the cooling water return passage are connected via a second bypass passage having a small diameter. It is.

[Effect]

In this configuration, when the temperature of the cooling water is low, the thermo-valve cuts off the communication of the cooling water return passage to the cooling water pump and also communicates the first bypass passage with the cooling water pump, so that the cooling water of the cylinder head is The cooling water in the cylinder flows out from each cylinder into the intake preheating passage, and returns from the intake preheating passage to the cooling water chamber of the cylinder head via the first bypass passage, the cooling water pump, and the cooling water chamber of the cylinder block. Since it circulates, intake air can be preheated.

When the temperature of the cooling water increases, the thermo-valve connects the cooling water return passage to the cooling water pump and operates to close the first bypass passage, so that the cooling water in the cooling water chamber of the cylinder head is cooled. At the same time, a portion of the cooling water in the cylinder head cooling water chamber is circulated from the water outlet through the radiator, cooling water pump, and cylinder block cooling water chamber, and back to the cylinder head cooling water chamber. Preheating passage and second
The cooling water is circulated through the bypass passage and sucked into the cooling water pump.

That is, during normal operation after the cooling water has risen to a predetermined temperature, a portion of the cooling water circulating between the internal combustion engine and the radiator is stored in the intake preheating passage located at the highest point. Since the cooling water circulates through the two bypass passages, high-temperature cooling water circulating between the internal combustion engine and the radiator accumulates in the intake preheating passage due to convection. It is possible to reliably prevent high temperature cooling water from collecting in the intake air preheating passage.

In addition, by connecting the intake preheating passage located at the highest point in the cooling water circulation path to the cooling water filler via a small-diameter air vent passage, when injecting cooling water from the cooling water filler, the intake preheating passage All the air accumulated in the cooling water filler can be removed from the cooling water filler through the air vent passage.
By connecting the cooling water return passage from the radiator and the intake preheating passage or the air vent passage through the second bypass passage, the thermovalve in the thermovalve case communicates from the cooling water return passage to the cooling water pump. Even in a state where the
Since the air in the cooling water return passage from the radiator can be removed from the cooling water filler through the second bypass passage, it is extremely easy to fill the cooling water circulation passage to its full capacity, and Ensure that the circulation in which a portion of the cooling water in the cylinder head cooling water chamber flows out into the intake air preheating passage and then returns to the cylinder head cooling water chamber is obstructed by air accumulated in the intake air preheating passage. It can be prevented.

〔Effect of the invention〕

Therefore, according to the present invention, in a slant-type internal combustion engine, it is possible to reduce the labor required for injecting cooling water into the cooling water circulation path, and also to prevent the cooling water from preheating the intake air during warm-up operation when the temperature of the cooling water is low. This effect can be achieved reliably and accurately without causing a decrease in intake air filling efficiency during normal operation after warming up to a temperature of .

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a slant-type internal combustion engine in which the axis 2 of the cylinder bore is inclined by an appropriate angle θ with respect to the horizontal line 3 when viewed from the direction of the crankshaft. A cylinder head 5 on the upper surface of a cylinder block 4 of the internal combustion engine 1 is shown.
An intake manifold 7 that distributes intake air from the carburetor 6 to each cylinder is connected to the longitudinal side of the engine.

An intake preheating passage 9 is integrally formed on the lower surface of the intake manifold 7 and communicates with the cooling water chamber 8 of the cylinder head 5 at the location of each cylinder. A water outlet 10 is provided, and a cooling water outflow passage 12 that connects the cooling water outlet 10 and a top tank (not shown) of the radiator 11 is used to inject cooling water into the cooling water circulation path. A cooling water filler 13 with a cap is provided for the cooling water filler 13, and a small diameter air vent passage 14 from the intake preheating passage 9 is provided in the cooling water filler 13.
Connect.

A thermovalve case 15 is formed on the longitudinal side of the cylinder block 4, and a cooling water return passage 16 from a lower tank (not shown) of the radiator 11 is connected to the thermovalve case 15. A first cylinder is formed in the cylinder block 4 so as to communicate with the intake air preheating passage 9.
Bypass passage 17 is open. The thermovalve case 15 also communicates with the suction side of the cooling water pump 18 attached to the cylinder block 4 via a passage 21, and the cooling water discharged from the cooling water pump 18 is connected to the suction side of the cooling water pump 18 attached to the cylinder block 4. It is configured to return to the cooling water chamber 8 of the cylinder head 5 via a cooling water chamber (not shown).

In the thermovalve case 15, when the temperature of the cooling water is low, communication of the cooling water return passage 16 to the cooling water pump 18 is cut off, and the first bypass passage 17 is connected to the cooling water pump 18, so that the cooling water is cooled. When the water temperature is high, the cooling water return passage 16 is communicated with the cooling water pump 18 and the first bypass passage 17 is connected.
A thermovalve 19 configured to close the cooling water return passage 16 and the air vent passage 14 are connected via a second bypass passage 20 having a small diameter.

In this configuration, when cooling water is injected from the cooling water filler 13, air accumulated in the intake preheating passage 9 located at the highest point in the cooling water circulation path can be removed from the cooling water filler 13 via the air vent passage 14. On the other hand, even when the thermo-valve 19 in the thermo-valve case 15 blocks the communication from the cooling water return passage 16 to the cooling water pump 18, the air in the cooling water return passage 16 from the radiator 11 is Since the cooling water can be drawn out from the cooling water filler 13 through the two bypass passages 20, the cooling water circulation path can be fully filled with cooling water.

During operation of the internal combustion engine, when the temperature of the cooling water is low, the thermovalve 19 cuts off communication of the cooling water return passage 16 to the cooling water pump 18 and connects the first bypass passage 17 to the cooling water pump 18.
Since the cooling water in the cooling water chamber 8 of the cylinder head 5 flows out from each cylinder to the intake preheating passage 9, the cooling water flows from the intake preheating passage 9 to the first
Since the intake air is circulated through the bypass passage 17, through the cooling water pump 18 and the cooling water chamber of the cylinder block 4, and back to the cooling water chamber 8 of the cylinder head 5, the intake air can be preheated. Then, thermo valve 1
9 operates to connect the cooling water return passage 16 to the cooling water pump 18 and close the first bypass passage 17, so that the cooling water in the cooling water chamber 8 of the cylinder head 5 is transferred from the cooling water outlet 10 to the radiator 11. , the cylinder head 5 via the cooling water pump 18 and the cooling water chamber of the cylinder block 4.
At the same time, part of the cooling water in the cooling water chamber 8 of the cylinder head 5 flows out from each cylinder to the intake preheating passage 9, and then flows through the air vent passage 14 and the second bypass passage. 2
The cooling water is circulated through 0 and sucked into the cooling water pump 18.

That is, during normal operation after the cooling water has risen to a predetermined temperature, a portion of the cooling water circulating between the internal combustion engine 1 and the radiator 11 is stored in the intake preheating passage 9 located at the highest point. Since the cooling water is circulated through the second bypass passage 20, high-temperature cooling water circulating between the internal combustion engine 1 and the radiator 11 is transferred into the intake preheating passage 9 by convection. In other words, it is possible to reliably prevent high-temperature cooling water from gathering in the intake air preheating passage 9.

Note that the air vent passage 14 may be connected to a cooling water filler (not shown) provided in the radiator 11 instead of being connected to the cooling water filler 13 provided in the cooling water outflow passage 12. Furthermore, the second bypass passage 20 may be directly connected to the intake air preheating passage 9 instead of being connected to the air vent passage 14.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a plan view of an internal combustion engine, FIG. 2 is a cross-sectional view taken from the side of FIG. 1,
FIG. 3 is a cross-sectional view taken from the side in FIG. 1. 1... Internal combustion engine, 2... Axis of cylinder bore,
3...Horizontal line, 4...Cylinder block, 5...
Cylinder head, 7... Intake manifold, 8...
...Cylinder head cooling water chamber, 9...Intake preheating passage, 10...Cooling water outlet, 11...Radiator, 12...Cooling water outflow passage, 13...Cooling water filler, 14...Air vent passage, 15... ...Thermo valve case, 16...Cooling water return passage, 17...
...First bypass passage, 18...Cooling water pump, 1
9... Thermo valve, 20... Second bypass passage.

Claims (1)

[Claims] 1 The axis of the cylinder bore when viewed from the direction of the crankshaft is inclined with respect to the horizontal line, and
In a slant type internal combustion engine, the intake manifold connected to the longitudinal side of the cylinder head is provided with an intake preheating passage communicating with the cooling water chamber of the cylinder head at a location of each cylinder,
The intake preheating passage is connected to the cooling water outflow passage from the cooling water outlet of the cylinder head to the radiator or to the cooling water filler provided in the radiator via a small-diameter air vent passage, while the air intake preheating passage is connected to the cooling water outflow passage from the cooling water outlet of the cylinder head to the radiator or to the cooling water filler provided in the radiator through a small diameter air vent passage, In the cooling water return passage leading to the cooling water chamber, a thermovalve case is provided on the suction side to the cooling water pump, and a small diameter first bypass passage from the intake preheating passage is connected to the thermovalve case, Moreover, a first valve is provided in the thermovalve case to cut off communication of the cooling water return passage to the cooling water pump when the temperature of the cooling water is low.
A thermo valve configured to communicate the bypass passage with the cooling water pump and communicate the cooling water return passage with the cooling water pump and close the first bypass passage when the temperature of the cooling water is high is provided; Alternatively, a cooling device for a slant-type internal combustion engine, wherein the air vent passage and the cooling water return passage are connected via a second bypass passage having a small diameter.