JPS6214338Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an air-cooled engine that cools the engine with low-temperature air by utilizing the temperature drop when air expands.

Generally, in medium to large-sized internal combustion engines, the cylinder liner and cylinder head of the engine are usually water cooled because the heat capacity of air is small.
Conventionally, in order to cool the cylinder liner of an internal combustion engine, it was necessary to keep the temperature of the cooling water flowing on the surface of the cylinder liner below 80°C in order to keep the temperature around the first piston ring inside to below 200°C. Due to the structure of the engine, water that has cooled the cylinder liner flows through the cylinder head cooling water passage, so it is difficult to cool only the cylinder head at a high temperature (90° to 100°C). There are parts of the engine where the temperature is below the dew point, where water droplets are generated and combine with exhaust gas to form sulfuric acid, often resulting in so-called acid corrosion. Furthermore, cavitation damage often occurs on the outer periphery of the cylinder liner due to vibration of cooling water. Therefore, by air cooling the cylinder liner, the above-mentioned drawbacks caused by water cooling can be eliminated. On the other hand, in order to effectively cool the cylinder liner and use the air as supply air for the engine, the optimum temperature for the supply air is 40℃ to 60℃.
Due to the restrictions of be. In addition, as the performance and output of engines increase, the supply air pressure becomes higher and higher, and the increase in the supply air pressure causes an increase in moisture after the supply air is cooled, and if this is not efficiently recovered, This can cause abnormal wear on the intake valves and damage such as cracks to the valves.

This idea was made in view of the above, and by taking advantage of the fact that the temperature decreases when air expands, this low-temperature air is used to cool the engine cylinder liner, and furthermore, this air is used as the engine supply air. It is an object of the present invention to provide an air-cooled engine that can be used as an air-cooled engine to solve the above-mentioned problems. An embodiment of this invention will be described below based on the drawings.

In the drawing, reference numeral 1 denotes an exhaust turbine supercharger that is driven by the exhaust gas of the internal combustion engine E and compresses intake air, and its turbine inlet is connected to the exhaust port of the cylinder head 3 of the internal combustion engine E through an exhaust pipe 2. ing. Reference numeral 4 denotes an air cooler that cools the air sent out from the supercharger 1 by heat exchange with cooling water from the piping 5, and includes first and second air ducts 6a,
It is connected to the blower outlet of the supercharger 1 via 6b. 7 reduces the cross-sectional area of the flow path of the air exiting the air cooler 4 to limit the flow rate of the air;
A throttle valve for discharging and expanding air into the trunk 8 of the internal combustion engine E via a third air duct 9 to the air cooler 4
The diameter of the aperture formed between the aperture plates is made variable by moving a pair of aperture plates, which are connected to the outlet of the aperture plate and whose inner ends face each other, toward and away from each other. The throttle valve 7 may be formed as an orifice with a variable throttle diameter using a throttle plate as described above, but it may also be formed as an orifice with a required fixed throttle diameter, or it may be in the form of a gate valve or the like. , the key is to reduce the cross-sectional area of the air flow path,
Various types can be adopted as long as the flow rate is restricted. Reference numeral 10 denotes a drain separator that recovers moisture contained in the air that expands after exiting the throttle valve 7 and whose temperature has decreased. One end is connected to the throttle valve 7, and the other end is connected to the air intake trunk 8 of the internal combustion engine E. installed at the entrance. This drain separator 1
The bottom of the tank 0 serves as a drain reservoir 10a, and a drain pipe 12 having a pot 11 is connected thereto. 13 is an intake branch pipe that connects the outlet of the air intake trunk 8 formed to surround the outer periphery of the engine cylinder liner 14 and the intake port of the engine cylinder head 3; 15 is an intake valve provided in the cylinder head 3; . Reference numeral 16 denotes a baffle plate provided on the inner wall of the air supply trunk 8 so that the air supplied into the air supply trunk 8 does not go directly to the intake branch pipe 13.

In the device configured as described above, the exhaust gas is compressed by the exhaust turbine supercharger 1 of the internal combustion engine to a pressure of approximately 2 kg/kg.
cm ² , the air with a temperature of 160° to 180°C is transferred to duct 6.
After being cooled to about 60°C by the air cooler 4 through the air filters a and 6b, the throttle valve 7 and the drain separator 10
As the air is discharged into the air supply trunk 8 and expanded, the pressure decreases to approximately 1 kg/cm ² and the temperature to 10° to 20° C. This low temperature air is transferred to the drain separator 10.
After the moisture in the air is collected in the air supply trunk 8
The air flows around the cylinder liner 14 and cools the cylinder liner 14, and the air itself is heated by heat radiation from the cylinder liner 14 and its temperature rises to 40° to 60°C.
The water that cannot be removed at 0 is re-vaporized. During the intake stroke of the engine E, this air reaches the intake port of the cylinder head 3 from the outlet of the intake trunk 8 through the intake branch pipe 13, and is sucked into the engine cylinder. Since the water collected by the drain separator 10 is stored in the drain reservoir 10a, the drain tank 11 is opened at any time to drain it. Note that the throttle valve 7 is adjusted so that the amount of air taken into the engine E and the amount of air flowing into the air supply trunk 8 through the throttle valve 7 are balanced.
Since the diameter of the throttle valve is set, the pressure inside the air supply trunk 8 will not increase and the pressure difference before and after the throttle valve will not disappear.

As mentioned above, this idea cools the air compressed by the supercharger through an air cooler, and then
The air passes through the throttle valve and is discharged into the engine's air supply trunk and expanded to lower the air temperature. This low-temperature air cools the cylinder liner, and the air whose temperature has risen due to cooling the cylinder liner is supplied to the engine cylinder. Since the air cooler can be cooled efficiently, the cylinder liner can be cooled efficiently, and the air cooler can be a normal water cooling type, and does not require a very large structure. In addition, due to an increase in the engine supply air pressure, the moisture in the supply air that increases after the supply air is cooled is the remainder that was not recovered by the drain separator. As a result of re-vaporization, the moisture recovery rate improves, and the air with moisture recovered in this way is at an appropriate temperature and can be used as air supply to the engine cylinders. damage can be prevented. Further, since there is no need to attach a special heating device to raise the temperature of the air and revaporize it as described above, the structure of the device is simple and its implementation is easy. In addition, since the cylinder liner is not cooled with water, the total amount of engine cooling water can be reduced and the cylinder head can be cooled at high temperatures, preventing acid corrosion of the cylinder head and preventing acid corrosion caused by vibration of the cooling water. This has the advantage that cavitation damage to the cylinder liner can be eliminated.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of an air-cooled engine according to the present invention, and FIG. 2 is a partially sectional plan view of the air-cooled engine. 1...supercharger, 3...engine cylinder head, 4
... Air cooler, 7 ... Throttle valve, 8 ... Air supply trunk, 13 ... Intake branch pipe, 14 ... Cylinder liner.

Claims (1)

[Scope of utility model registration request] An air intake trunk provided to surround the outer periphery of each cylinder liner of the internal combustion engine, a throttle valve provided in communication with an inlet of the air intake trunk, and a supercharger driven by the exhaust gas of the internal combustion engine. , an air cooler that cools the air compressed by the supercharger and sends it to the throttle valve, and an intake branch pipe that connects the outlet of the air supply trunk to the intake port of the engine cylinder head. Features an air-cooled engine.