JPS62251416A - Cooling system for internal combustion engine - Google Patents

Abstract

PURPOSE:To promote the improvement of suction efficiency and to prevent the decrease of mechanical efficiency due to excessive cooling, by allowing cooling water to flow into a cylinder head from the upper part jacket of a cylinder liner and introducing the cooling water, after it is heated, to the bottom part jacket of the cylinder liner. CONSTITUTION:Cooling water, delivered from a cooling water pump 21, is allowed to flow into the bottom of an upper part jacket 30, constituted by a partition 16 provided between the intermediate part of a cylinder liner 12 and a crankcase 11, and into a cooling water reservoir in a cylinder head 13 from a communication hole 23 provided in the upper of the upper part jacket 30. The cooling water from the cylinder head 13 passes through an outlet pipe 41, and the cooling water, after it is heated in a cooling water passage 43 around an exhaust pipe 42, is introduced to a bottom part cooling water jacket 22. The cooling water from the bottom part cooling water jacket 22 returns again to the cooling water pump 21 through a thermostat 27 and a radiator 28.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improving the performance of water-cooled internal combustion engines.

[Conventional technology]

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In the figure, 11 is a crankcase, 12 is a cylinder liner, 13 is a cylinder head, 14 is a piston, and 15 is a cylinder liner.
is a combustion chamber, 21 is a cooling water pump, 22.30 is a cooling water lower and upper jacket, 23 is a communication hole, 24 is a cooling water reservoir, 25 is a cooling water outlet pipe, 27 is a thermostat, 28 is a radiator, 29.31 is Piping, 32 is an air supply pipe, 33 is an air supply passage, 34 is an exhaust pipe, and 35 is a crankshaft.

The crankcase 11 supports a cylinder liner 12, a cylinder head 13 is mounted on the upper part of the cylinder liner 12, and a piston 14 slides on the inner surface of the cylinder liner 12.

Further, the cooling water discharged from the cooling water pump 21 driven by the crankshaft 35 which forms the combustion chamber 15 with the cylinder head 13, the cylinder liner 12, and the piston 14 is composed of the crank case 11 and the cylinder liner 12. The cylinder liner 1 enters the lower part of the cooling water jacket 22.
The cooling water flows into the cooling water reservoir 24 of the cylinder head 13 through the communication hole 23 located at the top. Air is supplied to the combustion chamber 15 from an air supply pipe 32 through an air supply passage 33 in the shilling head 13 .

Further, exhaust gas from the combustion chamber 15 is discharged from an exhaust passage in the cylinder head 13 (not shown) through an exhaust pipe 34.

Here, the cooling water in the cylinder head cooling water reservoir 24 flows around the air supply passage 33 as shown in the figure, and then passes through the cooling water outlet pipe 25 to reach the thermostat 27. From the thermostat 27, it passes through the ranoator 28 and piping 29, and a part of it passes through the pipe and gas piping 31 and is directly connected to the cooling water pump 2.
This leads to the 1st suction port.

Next, the operation of the conventional example will be explained.

The cooling water discharged from the cooling water pump 21 first cools the cylinder liner 12 in the cooling water jacket 22, and after the temperature rises, it flows into the cooling water reservoir 24 of the cylinder head X3 through the communication hole 23. Here, the thermostat 27 sets the water temperature of the cylinder head to 80°C, and the cooling water temperature of the cooling water outlet pipe 25 is maintained at approximately 80"GK. Therefore, the air supply passage 33 in the cooling water reservoir 24 is set at approximately 80"GK. °C cooling water. However, the supply air flowing from the air supply pipe 32 into the air supply passage 33 is normally about 20 °C above atmospheric temperature.
It is C. Therefore, the supply air flowing through the supply air passage 33 is heated by the cooling water in the cooling water reservoir 24, and after the temperature rises, it is sent to the combustion chamber. This has the same effect as an increase in atmospheric temperature, resulting in a reduction in power output and deterioration in fuel efficiency. Incidentally, according to the output modification formula of JIS D I O05-1976, the output modification coefficient is expressed by the following formula.

Pa: Measured atmospheric pressure (Hg) Pw: Partial pressure of water vapor in the atmosphere (Hg) θ: Suction air temperature °C) Here, the supply air at a standard suction state of 20°C is approximately 2
The temperature rises by 0°C to 40°C, resulting in a 3.3% decrease in output and deterioration of fuel efficiency, which greatly affects engine performance.

[Problem that the invention seeks to solve]

As mentioned above, the cooling water that flows into the cylinder head has cooled the cylinder and raised its temperature considerably, and the intake air is heated by this raised cooling water, reducing the intake efficiency and causing the cylinder to become hotter than necessary. Since the engine is cooled by 100%, it has the disadvantage of reducing output and deteriorating fuel efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cooling system for an internal combustion engine that eliminates the drawbacks of the conventional devices, improves intake efficiency, prevents overcooling of the cylinder, increases output, and reduces fuel consumption.

[Means for solving problems]

The cooling system for an internal combustion engine according to the present invention divides the cooling water jacket of the cylinder liner into upper and lower parts, and allows the cooling water from the cooling water pump to first flow into the upper part of the jacket and then flow into the cylinder head. By doing so, the temperature of the upper part of the cylinder liner and the cylinder head is lowered, and the cooling water flowing out from the cylinder head is heated by exhaust or an oil cooler and then allowed to flow into the lower jacket of the cylinder liner.

[Effect]

The cylinder 2 iner jacket is divided into upper and lower parts to allow cooling water to flow from the upper jacket to the cylinder head, reducing the temperature of the cooling water flowing into the cylinder head and improving suction efficiency. Since cooling water heated by the oil cooler is allowed to flow in, overcooling of the cylinder liner can be prevented, improving engine output and reducing fuel consumption.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a structural diagram of a first embodiment of the present invention, and FIG. 2 is a diagram corresponding to FIG. 1 of the second embodiment.

In the figure, 11 is a crankcase, 12 is a cylinder liner, 13 is a cylinder head, 14 is a piston, 15 is a combustion chamber, 16 is a partition, 21 is a cooling water pump, 22 is a cooling water lower jacket, 30 is the same upper jacket, 23 is a communication hole, 24 is a cylinder head water reservoir, 27 is a thermostat l-, 28 is a lanoator, 29, 31, 41, 44.
45 is a chilled water pipe, 32 is an intake pipe, 33 is an intake passage, 4
2 is an exhaust pipe, and 43 is a cooling water passage.

In FIG. 1, the cooling water discharged from the cooling water pump 21 first flows from below the upper jacket 30 formed by the partition 16 provided between the middle part of the cylinder liner 12 and the crankcase 11. Communication hole 2 above it
3 into the cooling water reservoir 24 of the cylinder head 13. Further, a cooling water passage 43 is provided around the exhaust pipe 42. The cooling water from the cylinder glock 13 passes through the outlet pipe 41 and the cooling water passage 43 of the exhaust pipe 42, and then is introduced into the lower cooling water jacket 22 of the crankcase 11 through the piping 44. Thereafter, the cooling water flows out from above the lower cooling water jacket and reaches the thermostat 27 via the pipe 45.

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

The radiator 2 is controlled at a constant temperature by the thermostat 27.
The cooling water cooled at step 8 flows from below the upper jacket 30 of the cylinder liner 12 from the cooling water pump 21,
It flows into the cooling water reservoir 24 of the cylinder head 13 through the communication hole 23 . At this time, since the temperature of the cooling water flowing into the upper part of the cylinder liner 12 and the cylinder head part 13 is low,
The degree to which the supply air is heated is low, and the engine's suction efficiency is improved.

The relatively high-temperature cooling water that cools the cylinder head 13 and flows out from the cooling water reservoir 24 is further heated by exhaust gas in the cooling water passage 43 of the exhaust pipe 42 and then flows into the lower cooling water jacket 22 of the cylinder Glock 11. Since it flows in, overcooling of the lower part of the cylinder liner is prevented, and engine output and fuel efficiency can be improved.

FIG. 2 shows a second embodiment of the present invention, in which the cooling water flowing out from the cooling water reservoir 24 of the cylinder head flows into the oil cooler 51 to cool the oil, and at the same time is heated and the cooling water reaches a high temperature. Therefore, the same effect as in the first embodiment where heating is achieved by exhaust gas in the cooling passage 43 of the exhaust pipe 42 can be obtained.

〔Effect of the invention〕

The cooling system for two internal combustion engines according to the present invention allows the cooling water from the water pump cooled by the cooler to flow into the cylinder head from the upper part of the cylinder liner, which lowers the cooling water temperature, improves the intake efficiency, and improves the engine output. can be measured. In addition, since the cooling water flowing out from the cylinder head is heated by the exhaust gas or oil cooler and then flows into the lower jacket of the cylinder block, a decrease in mechanical efficiency due to overcooling of the cylinder is prevented, improving engine output and reducing fuel consumption. can be realized.

[Brief explanation of the drawings] Fig. 1 is a diagram of the cooling system of the first embodiment of the present invention, Fig. 2 is a diagram corresponding to Fig. 1 of the second embodiment, and Fig. 3 is a diagram of the cooling system of the conventional example. be. DESCRIPTION OF SYMBOLS 11... Crank case, 12... Cylinder liner, 13... Cylinder head, 21... Cooling water pump, 22... Lower cooling water jacket of crank case,
30... Upper cooling water jacket, (42, 43). 51... Cooling water heating means. 21: Cooling water pump

Claims (1)

[Claims] In a water-cooled engine where the cylinder head and cylinder liner are cooled with water, the cooling water jacket of the cylinder liner is divided into upper and lower parts, and the cooling water discharged from the cooling water pump flows into the upper jacket of the crankcase, and then communicates with the cylinder head. A means for heating the cooling water is provided between the cylinder head outlet and the cylinder jacket lower inlet, and the cooling water heated by the means is caused to flow into the lower jacket of the crankcase. Features a cooling system for internal combustion engines.